Material-saving container cap and associated container neck

A material savings container cap comprising a circular flat top having a perimeter, an annular segmented container cap wall, each separated segment of container wall descending from a different portion of the perimeter of the top, the container cap wall having an internal screw thread for interlocking with a container wall of the container neck wherein an angle of threading to the container cap wall is between approximately thirty degrees and approximately forty-five degrees. The container neck wall has an external screw thread having an angle to the container neck wall of approximately thirty degrees. The internal screw thread always points towards an inner surface of the top of the cap and towards an axis of rotation of the cap. In the container neck wall the external screw thread always points away from an opening of the container and away from an axis of rotation of the container neck.

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Description
TECHNICAL FIELD

This invention relates to container caps and their associated container necks, and more particularly such container caps and associated container necks wherein the container caps achieve a significant material saving.

BACKGROUND OF THE INVENTION

In the manufacturing process, the cost of raw materials is a basic and significant cost. Processes or methods that can eliminate portions of the cost of raw materials are valuable and much sought after. In the manufacturing of containers having screw-on container caps, the material constituting the actual container cap is a raw material that is usually thought of as a fixed cost that cannot be reduced other than by a change in material.

In the manufacturing process, the manufacturer is expected to meet certain achievement specifications. For example, in the case of a container cap that screws on to a container neck, the manufacturer is expected to achieve a certain degree of tightening force with a certain amount of reliability. The manufacturer is also expected to achieve these results within a specified cost parameter.

Thus the threading on the cap and container neck must achieve a certain tightness needed to securely enclose the container and to do so within cost parameters defined by a third party.

It would be very advantageous to be able to achieve the same degree of torque from the container cap without having to spend the same amount of money for the raw material associated with the container cap itself and its associated container neck.

A container cap that does not contain the interlocking screw thread design form of the present invention will use superfluous material.

Known container caps are complete cylinders in that they have material forming the cap wall running continuously around the wall of the container cap without interruption. Prior art container caps also contain a threading having a cross-section that is “V” shaped.

Normally, it would be assumed that interrupting the wall of the container cap by having segments separated by spaces would undermine the force generated by the threading on the container cap and would make the threading slip apart of a mating relationship with the threading on the neck. It is also assumed that were there to be separate segments of a container cap wall these segments would be forced to be spread open by the force of the tightening.

It would be advantageous to have a container cap with reduced material in which the segments of materials would not spread apart from the force of the tightening and which would not cause the threading thereon to slip from its mating relationship.

The present invention achieves this and many other advantages.

SUMMARY OF THE PRESENT INVENTION

A material savings container cap and associated container neck is presented wherein the material savings container cap is comprised a circular flat top having a perimeter, an annular segmented container cap wall, each separated segment of container wall descending from a different portion of the perimeter of the top, the container cap wall having an internal screw thread design for interlocking with a container wall of the container neck wherein an angle of a threading to the container cap wall is between approximately thirty and forty five degrees. The container neck has a container neck wall having an external screw thread design for interlocking in mating relationship with the internal screw thread design of the container cap wall and having an angle of an external threading to the container neck wall that is between approximately thirty degrees and approximately forty-five degrees. The thread form of the material savings container cap is also unique and is described as the interlocking screw thread design from. The internal screw thread always points towards an inner surface of the flat top of the container cap and towards an axis of rotation of the container cap. The associated container neck has a container neck wall that has an external screw thread design for interlocking in mating relationship with the internal screw thread design of the container cap wall and wherein an external screw thread always points away from an opening of the container and away from an axis of rotation of the container neck.

IMPORTANT OBJECTS AND ADVANTAGES

The following important objects and advantages of the present invention are

    • (1) to provide a container cap and associated container neck that is economical;
    • (2) to provide material saving in the container cap
    • (3) to provide a container cap having segments
    • (4) to provide such a cap that does not have a complete cylinder of material that contains the internal threading
    • (5) to provide such a cap that is of the interlocking screw thread design form
    • (6) to provide such a cap that has spaces between segments of material on the container wall such that the spaces plus the segments form the complete cylinder of material that is characteristic of caps that are not of the material saving cap design.
    • (7) To provide such a cap which results in the saving of between 5% and 40% material savings compared to caps that are not of the material saving design.
    • (8) To provide a container cap and container neck container combination wherein the container cap has spaces in its container wall and has a unique threading
    • (9) To provide a container cap having an internal screw thread having an angle in the range of between approximately thirty degrees and approximately forty-five degrees between the thread and the cap wall
    • (10) To provide such a cap wherein the internal threading of the cap and the external threading of the container neck are such as to create a ratchet type locking effect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the container cap of the present invention screwed on to its associated container neck showing three segments.

FIG. 2 is a cross-sectional view of the preferred embodiment of the external (container neck) interlocking screw thread design

FIG. 3 is a cross-sectional view of the preferred embodiment of the internal (container cap) interlocking screw thread design

FIG. 4 is a cross-sectional view of an alternative embodiment of the external (container neck) interlocking screw thread design

FIG. 5 is a cross-sectional view of an alternative embodiment of the internal (container cap) interlocking screw thread design

FIG. 6 is a cross-sectional view of the alternative embodiment of the combined internal and external interlocking screw thread design shown separately in FIGS. 4 and 5 wherein the combined container cap and associated container neck is depicted

FIG. 7 is an enlarged fragmentary cross-sectional view of the alternative embodiment of the combined internal and external interlocking screw thread design showing the mating threads.

FIG. 8 is a horizontal cross-section of the container cap of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings the material savings container cap comprises a circular flat top which is a flat disk of variable thickness and consists of an exposed upper surface 1 and an enclosed inner surface 2. The area of physical contact between the enclosed inner surface and the rim of the associated container neck 14 forms the seal. The segments 3,9,10,46,50 are perpendicular extensions of the inner surface area of the material savings container cap and point away from it. The unique segments are separated by spaces. An example of a space, is the area bounded by the dashed lines 48,49 and the segments 46,50. The segments and spaces together form a complete cylinder in cross-section as shown in FIG. 8. The wall thickness of this cylinder is equal to the thickness of any segment. This cylinder consists of real and imaginary parts. The real parts are the segments. The imaginary parts are the spaces. Caps not of the material savings design do not have spaces but instead consist of a complete hollow cylinder of material. The wall of this hollow cylinder is located in the region that contains thread or threads and is used to support these thread or threads. The complete cylinder of the material savings cap has an axis of rotation that passes through the center of the circular flat top of the material savings container cap. The unique segments form an incomplete cylinder of material. The outer surface area of the segments merges into the circular flat top. The radius of the circular flat top and the radius from the center of rotation of any segment to the outer surface of its wall is equal. The presence of raised or recessed surfaces on the surface of the material savings cap are allowed. This is mainly for the purpose of product identification and aesthetics.

There are two different segment arrangements. The first is the simple segment arrangement. Here all the segments are of equal size and thickness and are arranged so that any reference point taken on any of the segments, makes the exact angle between that chosen point, the center of rotation of the segments and the same reference point on an adjacent segment. This all occurs in a plane parallel to that of the circular flat top of the material savings container cap as shown in FIG. 8. This angle is equal for every segment chosen for material savings container caps that comply with the single segment arrangement. The simple segment arrangement provides for generally equal load sharing between all the segments. The angle between the segments is determined by dividing 360 degrees by the required number of segments. The number of segments for the simple segment arrangement is a range. This range is the set of whole numbers from two to one hundred and are inclusive of these boundary values.

The second segment arrangement shall be known as the random segment arrangement where there can be any variation in shape and size between segments for the purposes of product identification and aesthetic reasons. Every point in space occupied by a segment is part of the standing walls of a cylinder. The wall thickness of this cylinder is equal to the thickness of any segment, since all the segments of any material savings cap are of equal thickness. The axis of rotation of this cylinder passes through the center of the circular flat top of the material savings container cap. The axis of rotation is perpendicular to the circular flat top. Each segment of the random segment arrangement is attached to and merges into the circular flat top. A variation in size and or shape of segments results in a change in surface area between segments that are different. The maximum holding force is directly proportional to the inner surface area of the segments. The inner surface area of a segment is that surface that is nearest to the axis of rotation.

The segment range of any material savings container cap will vary according to size of the cap, material used and the forces involved. The number of segments for the random segment arrangement is a range. This range is the set of whole numbers from two to one hundred and are inclusive of these boundary values.

The thread/threads of the material savings container cap go on the inner surface of the segments 3,10 and point up towards the material savings container cap's top. The thread/threads of the material savings container cap also point towards the axis of rotation of the material savings container cap. The thread/threads merge into the inner surface of the segments as shown in segments 3,10. The diameter of the imaginary cylinder bound by the inner surface of the segments and minus the thread/threads, is the major diameter of the material savings container cap. This is the same as twice the perpendicular distance between the axis of rotation 15 and the root of the thread 16. The thread/threads run along the imaginary cylinder whose inner surface diameter is the major diameter of the material savings container cap. The thread/threads occur only on those sections of the imaginary cylinder that coincide with the segments on the material savings container cap. Therefore the thread/threads occur only in those areas where the segments form real sections of the imaginary cylinder. The thread/threads of the material savings container cap is/are of the internal interlocking screw thread design forms whereas the thread/threads of the associated container neck is/are of the external interlocking screw thread design forms. There must be the same number of threads on the material savings container cap and its associated container neck 8. The associated container neck is cylindrical in form with its rim perpendicular to the axis of rotation of the associated container neck. It has a specific wall thickness throughout which is dependant upon customer requirements and materials used to manufacture it. The thread/threads on the material savings container cap start on any of the segments below the inner surface of the material savings container cap's top.

These thread/threads have the same axis of rotation as that described previously for the segments of the material savings container cap. The major diameter of the material savings container cap contains the root of the thread/threads. This therefore implies that the root of each thread for the material savings container cap of the basic internal interlocking screw thread design form is the inner segment surface only. Each thread of the material savings container cap is comprised of both imaginary and real sections. The real sections of the thread/threads are those sections that exist in segments. The imaginary sections of a thread are those regions of that thread that join the real sections of that thread together forming the characteristic helical curve of a thread. The position of the thread/threads for each segment is exactly the same as the position of the thread/threads section on that part of the imaginary cylinder which represents that particular segment.

The thread/threads of the associated container neck go on its external surface. These thread/threads are located below the rim of the associated container neck. The external interlocking screw thread design forms of the associated container neck of the material savings container cap always points away from the rim of the associated container neck. In addition the thread/threads also point away from the axis of rotation of the associated container neck. The cylinder wall of the associated container neck ends at the top in a plane perpendicular to the axis of rotation of the associated container neck.

The diameter of the external surface of the associated container neck minus the thread/threads is known as the minor diameter of the associated container neck. This diameter is taken in any plane perpendicular to the axis of rotation of the associated container neck. The minor diameter of the associated container neck is equal to twice the perpendicular distance between the axis of rotation 19 and the root of the thread 21. The thread/threads is/are continuous unlike the thread/threads on the material savings container cap which are intermittent.

The thread/threads of the associated container neck have corresponding thread/threads on the complimentary material savings container cap that mate with these thread/threads. The thread/threads of the material savings container cap and associated container neck fit together creating a unique interlocking effect. This interlocking between threads prevents movement or bending of the segments away from the axis of rotation when tightened onto its corresponding associated container neck.

The minor diameter of the associated container neck and the major diameter of the corresponding material savings container cap are dimensioned so as to allow for the required amount of clearance after the thread size is chosen. The fit between internal and external mating threads is dependant on the allowance given between these threads on assembly. The fit of the mating parts is dependant on customer requirements.

The interlocking screw thread design form is a unique thread form in form and function. The first unique feature of the interlocking screw thread design form is the orientation of the mating threads of the material savings container cap and the associated container neck. The thread/threads on the material savings container cap always point to the circular flat top whereas the thread/threads on the associated container neck always point away from the rim of the associated container neck. The thread/threads on the associated container neck always point away from the axis of rotation whereas the thread/threads on the material savings cap always point towards the axis of rotation. The assembly of the material savings container cap and associated container neck in cross section emphasize the importance of orientation of these threads in providing this locking force.

The second unique feature is the type of interlocking that occurs. This can be most clearly described by stating the maximum number of thread surfaces cut by a line 45 perpendicular to the axis of rotation 19 of mating threads of the rounded external and internal interlocking screw thread design forms 43,44. The surfaces cut by this line 45 are as follows:

    • The real rounded root of the rounded internal interlocking screw thread
    • The real crest of the rounded external interlocking screw thread
    • The real primary flank of the rounded external interlocking screw thread
    • The real primary flank of the rounded internal interlocking screw thread
    • The real crest of the rounded internal interlocking screw thread
    • The real rounded root of the rounded external interlocking screw thread

The maximum total number of surfaces cut by a line perpendicular to the axis of rotation and midway along the mating threads of any of the external and internal interlocking screw thread design forms are six surfaces. The maximum total number of surfaces cut by a line perpendicular to the axis of rotation and midway along the mating threads of any thread forms other than that of the external and internal interlocking screw thread design forms are two surfaces.

The Interlocking Screw Thread Design Form

The interlocking screw thread design form is divided into the external and internal interlocking screw thread design forms. The external and internal interlocking screw thread design forms are each further divided into two sub categories. The first is the basic external interlocking screw thread design form and the rounded external interlocking screw thread design form. The second is the basic internal interlocking screw thread design form and the rounded internal interlocking screw thread design form.

These thread design forms are best explained by examination of cross-sectional views of a material savings cap and its complimentary associated container neck. Each view is taken in a plane along the diameter of the material savings cap or associated container neck. FIGS. 2 to 6 show only half of that view since it contains all the relevant parts required for the description of a thread. A developmental approach shall be taken in the description of these thread forms.

The basic external interlocking screw thread design form is outlined in FIG. 2. A line is constructed parallel to the axis of rotation 19. The perpendicular distance between this construction line and the axis of rotation is half of the minor diameter of the associated container neck. The construction line contains the distance x which is the width of the thread and is measured in a direction parallel to the axis of rotation. The variable x is a measure of length and can be either metric or English units provided the chosen unit of length is maintained throughout. The width x is proportional to the holding force of the thread since it is directly related to thread size, however there are other determining factors. These factors are first physical data on the material type chosen in the manufacture of the associated container neck. Second is the maximum closing forces placed on the material savings cap and associated container neck assembly.

All threads of the basic external interlocking screw thread design form must adhere to the following constraints.

The flanks begin on either side of the distance x and extend away from it and the axis of rotation 19. The secondary flank 55 is that side of the thread that is closest to the opening of the associated container neck. The smallest angle the secondary flank makes with the distance x must be between 30 and 45 degrees and includes these boundary values. This angle is measured in a counter-clockwise direction from the axis of rotation. The angle shall be denoted by the variable α. The primary flank 52 is the side of each thread that is furthest away from the opening of the associated container neck. The primary flank is equal in length and parallel to the secondary flank. The flank length is measured parallel to the flank. The flank length shall be denoted by the variable F. The greatest length a flank of the basic external interlocking screw thread design form can have is 3x. The least length a flank of the basic external interlocking screw thread design form can have is 0.3x.

The crest of a thread is flat and parallel to the axis of rotation. The width of the thread of the basic external interlocking screw thread design form is uniform throughout therefore the crest width is equal to x.

The height of a thread is measured in a direction perpendicular to the axis of rotation of that thread. The height of a thread is the distance between the crest and the root of that thread. The height shall be denoted by the variable H. The height is given by the formula H=F(sin α). The greatest height is directly proportional to the greatest flank length 3x and is shown in FIG. 2 by the perpendicular distance between the crest 20 and the root 21. The least height is directly proportional to the least flank length 0.3x and is shown by the perpendicular distance between the dashed line 22 and the root 21. The dashed line 22 depicts a region in space and is not the crest of the thread in FIG. 2.

The root 21 is the space between adjacent crests. The root width is a measure of that distance between threads at their base and is parallel to the axis of rotation. The root is also part of the construction line referred to in the description of x. The root shall be denoted by the variable R. The root is given by the formula R=x+y where y is the set of positive real numbers from 0 to 5x and is inclusive of these boundary values. The variable y provides for clearance between mating threads.

The description above for the basic external interlocking screw thread design form, with reference to FIG. 2 provides for an area within which the thread can exist. This area cannot exist for a thread height that falls outside this boundary area. This boundary area is enclosed by the secondary flank 55, the primary flank 52, the least crest height of a thread 22, the greatest crest height of a thread 20.

The basic internal interlocking screw thread design form is outlined in FIG. 3. All threads of the basic internal interlocking screw thread design form must adhere to the following constraints.

A line is constructed parallel to the axis of rotation of the material savings cap 15. The perpendicular distance between this construction line and the axis of rotation 15 is the major radius or half of the major diameter of the material savings cap. This distance is determined by the formula ½D1=(D+γ)½ where D1 is the major diameter of the material savings cap, D is the minor diameter of the associated container neck and γ is a real positive number that is no greater than ½H. The value γ provides for clearance between the mating threads when the material savings cap is screwed onto its associated container neck.

The variable x remains the same for the thread width of the basic external and internal interlocking screw thread design forms and lies on the construction line mentioned previously for the basic internal interlocking screw thread design form.

The flanks of the thread begin on either side of the distance x. The flanks extend away from x and towards the axis of rotation 15. The primary and secondary flanks of the basic internal interlocking screw thread design form are parallel to each other. The angle the flanks of the thread make relative to the axis of rotation shall be known as β. This angle is measured in a counter-clockwise direction relative to the axis of rotation 15. The formula for this new angle is β=180+α. The length of the flanks F is the same as that chosen for the basic external interlocking screw thread design form. Therefore the same limits of flank length apply. The flank length therefore falls within the range 0.3x to 3x and is inclusive of these boundary values. The primary flank 53 is the side of the thread that is closest to the inner surface of the circular flat top of the material savings cap. The secondary flank 54 is that side of the thread that is furthest away from inner surface of the circular flat top of the material savings cap. The arrow on the axis of rotation 15 points to the circular flat top of the material savings cap.

The thread height of the basic internal interlocking screw thread design form is a measure of the perpendicular distance between the crest and the root of the thread. This height is equal to H the height of the basic external interlocking screw thread design form. The crest is parallel to the axis of rotation 15 and is equal to x when measured in a direction parallel to the axis of rotation. The root 16 is the space between adjacent primary and secondary flanks. The root width is parallel to the axis of rotation 15. The root width is the same as that for the basic external interlocking screw thread design form and is equal to R.

The dashed line 18 represents the crest position that has the least height allowed by the basic internal interlocking screw thread design form. The crest 17 represents the crest position that has the greatest height allowed by the basic internal interlocking screw thread design form. The description above for the basic internal interlocking screw thread design form, with reference to FIG. 3 provides for an area within which the thread can exist. The thread cannot exist if the height of the thread causes it to fall outside this boundary area. The boundary area of FIG. 3 is the secondary flank 54, the primary flank 53, the least crest height 18, and the greatest crest height 17.

The internal interlocking screw thread design form can also be looked at as two reflections of the external interlocking screw thread design form. The first reflection occurs with the mirror line as the axis of rotation. This is followed by a second reflection along a mirror line that is perpendicular to the axis of rotation 19. This mirror line does not cut any of the thread surfaces. The axis of rotation changes and is located by the formula ½D1=(D+γ)½ to the new position 15.

The pitch of the basic internal and external interlocking screw thread design forms are equal. The pitch shall be denoted by the symbol p. The formula for the pitch is p=2x+y.

The rounded external and internal interlocking screw thread design forms are a further development on the basic external and internal interlocking screw thread design forms.

The rounded external interlocking screw thread design form is outlined in figure 4. The rounded external interlocking screw thread design form is made up of real and imaginary parts. The imaginary parts are construction lines which are used to determine where the real parts of the thread lie. The profile of the basic external interlocking screw thread design form is shown in FIG. 4 by the crest 20, the secondary flank, the primary flank 6, 29,26 and the root 37,38. The secondary flank 55 (of the basic external interlocking screw thread design form) is not numbered in FIG. 4 since the difference between this and the real secondary flank 7 (of the rounded external interlocking screw thread design form) is very small and not visible in FIG. 4. The basic external interlocking screw thread design form is the framework upon which the rounded external interlocking screw thread design form is built around.

All threads of the rounded external interlocking screw thread design form must adhere to the following constraints. The determination of the thread width x and its position relative to the axis of rotation 19 are the same as that for the basic external interlocking screw thread design form.

The flanks go on either side of the distance x as shown by the secondary flank and the primary flank 26,6,29. The real primary flank 6 and real secondary flank 7 of the rounded external interlocking screw thread design form are always parallel to each other but are not equal in length. The greatest real secondary flank 7 is not equal to the greatest secondary flank 55 of the basic external interlocking screw thread design form. The angle the flanks make with the distance x measured in a counter clockwise direction is α. This angular constraint is the same as that for the basic external interlocking screw thread design form.

The height H of the real crest 24 is the perpendicular distance between the imaginary part 20 (of the crest) and real flat root 38 of the rounded external interlocking screw thread design form. The height of the rounded external interlocking screw thread design form is measured in the same way as that for the basic external interlocking screw thread design form H. The crest of the rounded external interlocking screw thread design form consists of a real and imaginary part. The real crest 24 of the rounded external interlocking screw thread design form is shown. The imaginary part is shown as 20 and is the crest for the basic external interlocking screw thread design form. The real crest 24 of the rounded external interlocking screw thread design form, in FIG. 4 is the maximum crest height that can exist for the rounded external interlocking screw thread design form.

The real crest 24 of the rounded external interlocking screw thread design form is different to that of the basic external interlocking screw thread design form and is derived as follows. A construction line 25 is drawn so that it divides the angle between the lines 20 and 26 in half. A construction line 23 is then drawn that connects the construction line 25 with the junction where the secondary flank (of the basic external interlocking screw thread design form) meets the construction line 20. This connection is such that the angle formed between the construction lines 23 and 25 is 90 degrees. The junction where the construction line 23 and 25 meet is the center point of the arc 24. The diameter of the arc 24 is equal to the perpendicular distance between the real primary flank 6 and real secondary flank 7. This distance is taken perpendicular to either flank since they are parallel to each other. This also implies that the center of the arc 24 lies along a line. This line is parallel to either flank and midway between the flanks. The arc 24 merges into the secondary flank 7 and primary flank 6.

The real rounded root 39 of the rounded external interlocking screw thread design form is dependent on the real crest 31 of the rounded internal interlocking screw thread design form. The dashed lines in FIG. 5 indicate construction lines.

The basic internal interlocking screw thread design form is shown in FIG. 5 by the primary flank 33,4,36 ,the secondary flank, the crest 17 and the root 41,40. The secondary flank 54 (of the basic internal interlocking screw thread design form) is not numbered in FIG. 5 since the difference between this and the real secondary flank 5 (of the rounded internal interlocking screw thread design form) is very small and not visible in FIG. 5.

The thread width of the rounded external and internal interlocking screw thread design forms are equal. The primary and secondary flanks begin on either side of the distance x. The distance x is parallel to the axis of rotation of the material savings cap. The perpendicular distance between the axis of rotation 15 and the distance x is given by the formula ½D1=(D+γ)½ where D1 is the major diameter of the material savings cap, D is the minor diameter of the complimentary associated container neck and γ is a real positive number that is no greater than ½H. This is the same condition as that for the basic internal interlocking screw thread design form.

The primary flank lengths of the rounded external and internal interlocking screw thread design forms are equal. The secondary flank lengths of the rounded external and internal interlocking screw thread design forms are also equal. The primary and secondary flanks of the rounded internal interlocking screw thread design form are parallel to each other. The primary flank 4,33,36 consists of real and imaginary parts. The real primary flank 4 and the real secondary flank 5 of the rounded internal interlocking screw thread design form are shown in FIG. 5. The angle the flanks of the thread make relative to the axis of rotation shall be known as β. This angle is measured in a counter-clockwise direction relative to the axis of rotation 15. The formula for this new angle is β=180+α. This angle is the same as that for the basic internal interlocking screw thread design form. The height of the thread of the rounded internal interlocking screw thread design form is equal to H. H is measured in the same way as that for the rounded external interlocking screw thread design form. The height H of the thread is the same as that height for the complimentary thread of the rounded external interlocking screw thread design form.

The crest of the rounded internal interlocking screw thread design form consist of real and imaginary parts. The real part shall be known as the real crest 31 of the rounded internal interlocking screw thread design form. The imaginary part 17 of the rounded external interlocking screw thread design form is the crest of the basic internal interlocking screw thread design form. The real crest 31 of the rounded internal interlocking screw thread design form is different to that of the basic internal interlocking screw thread design form and is derived as follows. A construction line 32 is drawn so that it divides the angle between the lines 17 and 33 in half. A construction line 30 is then drawn that connects the construction line 32 with the junction where the secondary flank (of the basic internal interlocking screw thread design form) meets the construction line 17. This connection is such that the angle formed between the construction lines 30 and 32 is 90 degrees. The junction where the construction lines 30 and 32 meet is the center point of the arc 31. The diameter of the arc 31 is equal to the perpendicular distance between the real primary flank 4 and real secondary flank 5 of the rounded internal interlocking screw thread design form. This distance is taken perpendicular to either flank since they are parallel to each other. This also implies that the center of the arc 31 lies along a line. This line is parallel to either flank and midway between the flanks. The arc 31 merges into the real secondary flank 5 and real primary flank 4 of the rounded internal interlocking screw thread design form.

The conditions are now set to determine the structure of the root of the rounded external interlocking screw thread design form shown in FIG. 4. The following construction lines 33,32,17,30,31 of FIG. 4 shows the mating of this region of the rounded internal interlocking screw thread design form with the rounded external interlocking screw thread design form. The perpendicular distance between the construction lines 17 and 37 is equal to ½γ. The perpendicular distance between construction lines 29 and 33 is also equal to ½γ. This means that the perpendicular offset distance for the mating primary flanks of the rounded internal and external interlocking screw thread design forms are equal to ½γ. This also means that the perpendicular offset distance for the mating crests of the rounded internal and external interlocking screw thread design forms are equal to ½γ. The axis of rotation 19 shown in FIG. 4 is the same axis of rotation for the rounded internal interlocking screw thread design form parts shown in this figure. The root of the rounded external interlocking screw thread design form is made up of real and imaginary parts. The real parts are the real rounded root 39 of the rounded external interlocking screw thread design form and the real flat root 38 of the rounded external interlocking screw thread design form. The imaginary part of the root of the rounded external interlocking screw thread design form 37 is part of the root of the basic external interlocking screw thread design form. The real rounded root of the rounded external interlocking screw thread design form is formed as follows. The center of rotation of the arc 39 is located at the center of rotation of the arc 31 in FIG. 4. The arc 39 merges into the real flat root 38 and the real primary flank 6. The root length of the rounded external interlocking screw thread design form is equivalent to that of the basic external interlocking screw thread design form. This is given by the formula R=x+y where in this case y must always be greater than ½γ. The new range of y is from ½γ to 5x and does not include the lower boundary value.

The arc 27 shown in FIG. 4 depicts the minimum real crest height of the thread of the rounded external interlocking screw thread design form. The center of this arc 27 is located along a line. This line is parallel to the real secondary flank 7 and midway between the real primary flank 6 and real secondary flank 7 of the thread. The diameter of this arc is the perpendicular distance between the real primary and real secondary flanks of the rounded external interlocking screw thread design form. The location of the arc is determined by the construction of a line perpendicular to the axis of rotation that originates from the center of the arc 39 and extends away from the axis of rotation 19. This construction line is 28 in FIG. 4. The arc is tangential to the construction line 28, the real secondary flank 7 and the real primary flank 6 and merges into these surfaces.

The rounded external interlocking screw thread design form shown in FIG. 4 shows the boundary area where the thread can exists. This area is bounded by the arc 24 (or real crest), the arc 27, the real secondary flank 7 and the real primary flank 6.

The root of the rounded internal interlocking screw thread design form is made up of real and imaginary parts. The real parts are the real rounded root 42 and the real flat root 41 of the rounded internal interlocking screw thread design form.

The imaginary part of the root of the rounded internal interlocking screw thread design form 40 forms part of the root of the basic internal interlocking screw thread design form. The real rounded root of the rounded internal interlocking screw thread design form is formed as follows. The center of rotation of the arc 42 is located at the center of rotation of the arc 24 in FIG. 5. The arc 42 merges into the real flat root 41 and the real primary flank 4. The root length of the rounded internal interlocking screw thread design form is equivalent to that of the basic internal interlocking screw thread design. This is given by the formula R=x+y where in this case y must always be greater than ½γ. The new range of y is from ½γ to 5x and does not include the lower boundary value.

The arc 35 shown in FIG. 5 depicts the minimum real crest height of the thread of the rounded internal interlocking screw thread design form. The center of this arc 35 is located along a line. This line is parallel to the real secondary flank 5 and midway between the real primary flank 4 and real secondary flank 5 of the thread. The diameter of this arc is the perpendicular distance between the real primary and real secondary flanks of the rounded internal interlocking screw thread design form. The location of the arc 35 is determined by the construction of a line 34 (see FIG. 5) perpendicular to the axis of rotation that originates from the center of the arc 42 and extends toward the axis of rotation 15. The arc 35 is tangential to the construction line 34, the real secondary flank 5 and the real primary flank 4 and arc 35 merges into these surfaces. The perpendicular distance between the construction lines 20 and 40 is equal to ½γ. The perpendicular distance between construction lines 26 and 36 is also equal to ½γ. This means that the perpendicular offset distance for the mating primary flanks of the rounded internal and external interlocking screw thread design forms are equal to ½γ. This also means that the perpendicular offset distance for the mating crests of the rounded internal and external interlocking screw thread design forms are equal to ½γ. The location of the arc is determined by the construction of a line perpendicular to the axis of rotation that originates from the center of the arc 42 and extends towards the axis of rotation 15. This construction line is 34 in FIG. 5. The arc is tangential to the construction line 34, the real secondary flank 5 and the real primary flank 4 and merges into these surfaces. The rounded internal interlocking screw thread design form shown in FIG. 5 shows the boundary area where the thread can exists. This area is bounded by the arc 31 (or real crest), the arc 35, the real secondary flank 5 and the real primary flank 4.

The mating of the threads of the rounded external and internal interlocking screw thread design forms is shown in FIG. 6. FIG. 6 shows the relevance of the respective construction lines in the development of the rounded external and internal interlocking screw thread design forms. In addition it also shows the mating of the basic external and internal interlocking screw thread design forms when the outline of these thread design forms is deciphered from the solid and dashed lines.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the material savings cap screwed onto its associated container neck. This view is a side view looking along a line that enters perpendicularly into the page and center of segment 9. Segment 9 is perpendicular to this line of view and is in a direction parallel to the axis of rotation of the material savings cap. The dashed lines in the figure represent details that are hidden from view. The material savings cap is of the simple segment arrangement and is comprised of four segment. Only three segments 3, 9, 10 are shown in the drawing. The fourth is hidden from view and located on the opposite side of segment 9. The threads on the material savings cap are of the rounded internal interlocking screw thread design form. The angle α chosen for the flanks of the rounded external interlocking screw thread design form is 45 degrees, the width of the thread is x, the root R=1¼x, the pitch=2¼x, ½γ=0.05x.

The associated container neck is shown by 8. The threads of the associated container neck are of the rounded external interlocking screw thread design form. The real primary flank 4 and the real secondary flank 5 of the rounded internal interlocking screw thread design form are shown. The real primary flank 6 and the real secondary flank 7 of the rounded external interlocking screw thread design form are shown. The lines 11, 12 and 13 were introduced to provide a better perspective of the cylindrical shape of the associated container neck. These lines represent boundary regions or junctions of the thread. The line 11 represents the junction where the real crest of the rounded external interlocking screw thread design form becomes hidden from view. The line 13 represents the junction between the real crest and the real secondary flank of the rounded external interlocking screw thread design form meet. The line 12 represents the boundary between the real secondary flank of the rounded external interlocking screw thread design form and the external surface of the associated container neck meet. The rim of the associated container neck 14 is shown. The upper surface 1 and the enclosed inner surface 2 of the circular flat top are shown.

FIGS. 2 and 3 complement one another in the sense that FIG. 2 shows the external thread on the neck whereas FIG. 3 shows the internal thread on the cap.

FIG. 2 shows a cross-sectional view of the basic external interlocking screw thread design form. The view is taken by cutting along a plane that contains and is parallel to a diameter of the associated container neck. This plane also contains the axis of rotation 19 and is parallel to it and the plane is also perpendicular to the enclosed surface of flat top 2. FIG. 2 thus represents the view one sees when facing the plane of that cut. The view of FIG. 2 shows only half of the actual cross-section. In addition the view shows only a little more than two pitch lengths of thread. The half shown in FIG. 2 is that half above the axis of rotation 19 of the associated container neck. The angle α not shown in FIG. 2 is equal to 30 degrees. This is the angle a flank makes with the axis of rotation when measured in a counter clockwise direction. The arrow at the end of the axis of rotation points in the direction of the rim of the associated container neck. The secondary flank 55 and the primary flank 52 are equal to 3x in length. These flanks are parallel to each other. The maximum crest 20 and the minimum crest 22 are shown and are equal in length. The minimum crest 22 is shown by a dashed line ,and only indicates the position where the minimum crest would occur. The crests are parallel to the axis of rotation and each has a length denoted by the variable x. The root 21 is parallel to the axis of rotation 19 and has a length denoted by the formula R=x+y. The value for y in FIG. 2 was chosen as x. Therefore in this case R=2x.

FIG. 3 shows a cross-sectional view of the basic internal interlocking screw thread design form. The view is taken by cutting along a plane that contains and is parallel to a diameter of the material savings cap. This plane contains the axis of rotation 15 and is parallel to it. FIG. 3 thus represents the view one sees when facing the plane of that cut. The view of FIG. 3 shows only half of the actual cross-section. The half shown is that half above the axis of rotation 15 of the material savings cap. The view shows only a little more than two pitch lengths of thread. The diagram of FIG. 3 is dependent on dimension and angles chosen for FIG. 2 since it complements the latter. The angle β not shown in FIG. 2 is equal to 210 degrees and is derived from the formula β=α+180, where α for the complimentary associated container neck in FIG. 2 was chosen as 30 degrees. This is the angle a flank makes with the axis of rotation 15 when measured in a counter clockwise direction. The arrow at the end of the axis of rotation points in the direction of the circular flat top of the material savings cap. The secondary flank 54 and the primary flank 53 are equal to 3x in length. This length is equal to the length chosen for a flank in FIG. 2 which is the complimentary associated container neck. The primary flank 53 is parallel to the secondary flank 54. The maximum crest height of FIG. 2 is equal to the maximum crest height in FIG. 3. The minimum crest height of FIG. 2 is equal to the minimum crest height of FIG. 3. The maximum crest 17 and the minimum crest 18 are shown and are equal in length. The minimum crest 18 is shown by a dashed line and only indicates the position where the minimum crest would occur. The crests are parallel to the axis of rotation and each has a length of x. The root 16 is parallel to the axis of rotation 15 and has a length denoted R=2x which is derived from its complimentary associated container neck in FIG. 2.

FIG. 4 shows a cross-sectional view of the rounded external interlocking screw thread design form. The view is taken by cutting along a plane along a diameter of the associated container neck. This plane contains the axis of rotation 19 and is parallel to it. FIG. 4 thus represents the view one sees when facing the plane of that cut. The view of FIG. 4 shows only half of the actual cross-section In addition the view of FIG. 4 shows only a little more than two pitch lengths of thread. The half shown is that half above the axis of rotation 19 of the associated container neck.

The basic external interlocking screw thread design form of FIG. 2 is shown in FIG. 4. The crest 20, the primary flank 26,6,29, the secondary flank and the root 37, 38 of the basic external interlocking screw thread design form of FIG. 2 are shown. The secondary flank 55 of FIG. 2 is not numbered in FIG. 4. This is because the difference between the secondary flank 55 and the real secondary flank 7 of the (rounded external interlocking screw thread design form) is so small that it is not visible in FIG. 4. The following information can be inferred from FIG. 2. The angle α not shown in FIG. 4 is equal to 30 degrees. This is the angle a flank makes with the axis of rotation when measured in a counter clockwise direction. The arrow at the end of the axis of rotation points in the direction of the rim of the associated container neck. The crest 20 is parallel to the axis of rotation and has a length denoted by the variable x. The root is parallel to the axis of rotation 19 and has a length of 2x.

The rounded external interlocking screw thread design form is composed of real and imaginary parts. The imaginary parts are construction lines which are used to determine where the real parts of the thread lie. The construction lines are shown by dashed lines in FIG. 4. The primary flank 26,6,29 is divided into the real primary flank 6 and the imaginary part 26,29 of the rounded external interlocking screw thread design form. The real secondary flank 7 of the rounded external interlocking screw thread design form is shown. The crest is divided into the real crest 24 and the imaginary part 20 of the rounded external interlocking screw thread design form. The root is divided into the real rounded root 39, the real flat root 38 and the imaginary part 37 of the rounded external interlocking screw thread design form. The construction lines 33,32,17,31,30,28 are derived from the rounded internal interlocking screw thread design form of FIG. 5 and are positioned where the threads would mate. The axis of rotation of these construction lines is also the axis of rotation 19. The construction line 28 originates from the center of the arc 31 and is perpendicular to the axis of rotation 19. The minimum real crest height 27 is located tangential and merges into the real secondary flank 7, the real primary flank 6 and the construction line 28.

The construction line 25 is drawn so that it divides the angle between the construction lines 26 and 20 in half. A construction line 23 is then drawn that connects the construction line 25 with the junction where the secondary flank (of the basic external interlocking screw thread design form) meets the construction line 20. The angle formed between the construction lines 23 and 25 is 90 degrees.

FIG. 5 shows a cross-sectional view of the rounded internal interlocking screw thread design form. The view is taken by cutting along a plane along a diameter of the material savings cap. This plane contains the axis of rotation 15 and is parallel to it. FIG. 5 thus represents the view one sees when facing the plane of that cut The view of FIG. 5 shows only half of the actual cross-section. In addition the view shows only a little more than two pitch lengths of thread. The half shown is that half above the axis of rotation 15 of the material savings cap. The basic internal interlocking screw thread design form of FIG. 3 is shown in FIG. 5. The crest 17, the primary flank 33,4,36, the secondary flank and the root 40,41 of the basic internal interlocking screw thread design form of FIG. 3 are shown. The secondary flank 54 of FIG. 3 is not numbered in FIG. 5. This is because the difference between the secondary flank 54 and the real secondary flank 5 of the (rounded internal interlocking screw thread design form) is so small that it is not visible in FIG. 5. The following information can be inferred from FIG. 3.The angle β not shown in FIG. 5 is equal to 210 degrees. This is the angle a flank makes with the axis of rotation when measured in a counter clockwise direction. The arrow at the end of the axis of rotation points in the direction of the circular flat top. The crest 17 is parallel to the axis of rotation and has a length denoted by the variable x. The root is parallel to the axis of rotation 15 and has a length of 2x.

The rounded internal interlocking screw thread design form is composed of real and imaginary parts. The imaginary parts are construction lines which are used to determine where the real parts of the thread lie. The dashed lines are construction lines in FIG. 5. The primary flank 33,4,36 is divided into the real primary flank 4 and the imaginary parts 33,36 of the rounded internal interlocking screw thread design form. The real secondary flank 5 of the rounded internal interlocking screw thread design form is shown. The crest is divided into the real crest 31 and the imaginary part 17 of the rounded internal interlocking screw thread design form. The root is divided into the real rounded root 42, the real flat root 41 and the imaginary part 40 of the rounded internal interlocking screw thread design form. The construction lines 20,26,25,23,24,34 are derived from the rounded external interlocking screw thread design form of FIG. 4 and are positioned where the threads would mate. The axis of rotation of these construction lines is also the axis of rotation 15. The construction line 34 originates from the center of the arc 24 and is perpendicular to the axis of rotation 15. The minimum real crest height 35 is located tangential and merges into the real secondary flank 5, the real primary flank 4 and the construction line 34.

The construction line 32 is drawn so that it divides the angle between the construction lines 17 and 33 in half. A construction line 30 is then drawn that connects the construction line 32 with the junction where the secondary flank (of the basic internal interlocking screw thread design form) meets the construction line 17. The angle formed between the construction lines 30 and 32 is 90 degrees.

FIG. 6 shows a cross-sectional view of the mating threads of the rounded internal and external interlocking screw thread design forms. The view is taken in a plane along a diameter of the material savings cap and associated container neck. This plane contains the axis of rotation 19 and is parallel to it. The view of FIG. 6 shows only half of the actual cross-section. The half shown is that half above the axis of rotation 19 of the material savings cap and complimentary associated container neck. This view shows only a little more than two pitch lengths of thread. This view is used to show the numbered items and the relevance of these items when compared to FIGS. 4 and 5. The dashed lines are construction lines in FIG. 6. The thread width is x. The flank length is 2.4x. The angle α=30 degrees for the rounded external interlocking screw thread. The angle β=210 degrees for the rounded internal interlocking screw thread. The root width R=2x. The pitch=3x and ½γ=0.05x.

FIG. 6 is used to emphasize the importance of the construction lines in the determination of where the real rounded crests and real rounded roots of the rounded external and internal interlocking screw threads lie. The thread parts are the same as that detailed in FIGS. 4 and 5.

FIG. 7 shows a cross-sectional view of the mating threads of the rounded internal and external interlocking screw thread design forms. The view is taken in a plane along a diameter of the material savings cap and associated container neck. This view contains the axis of rotation 19 and is parallel to it. The view of FIG. 7 shows only half of the actual cross-section. The half shown is that half above the axis of rotation 19 of the material savings cap and complimentary associated container neck. The rounded external interlocking screw thread 44 and the rounded internal interlocking screw thread 43 are shown without the construction lines used to derive them. The dashed line 45 is drawn perpendicular to the axis of rotation and passes through the center of rotation of arcs that form the real crests of the rounded external and internal interlocking screw threads. The total number of surfaces cut by line 45 are six. These surfaces are the following:

    • (i) The real rounded root of the rounded internal interlocking screw thread;
    • (ii) The real crest of the rounded external interlocking screw thread;
    • (iii) The real primary flank of the rounded external interlocking screw thread;
    • (iv) The real primary flank of the rounded internal interlocking screw thread;
    • (v) The real crest of the rounded internal interlocking screw thread; and
    • (vi) The real rounded root of the rounded external interlocking screw thread.

FIG. 8 shows a cross-section of the material savings cap. This cross-section is taken perpendicular to the axis of rotation and along the segments. There are four segments of the simple segment arrangement two of which are numbered 46, 50. The view of FIG. 8 shown is taken looking into the page along the axis of rotation 15 of the material savings cap, the axis of rotation 15 being a point located at the intersection of lines 47 and 51 (and the axis of rotation 15 being perpendicular to the page on which FIG. 8 appears). The axis of rotation 15 extends perpendicularly out of the page. The internal interlocking screw thread cannot be visibly distinguished from the view of FIG. 8. The dashed lines 47 and 51 all connect the same sides of all the segments. The angle between the dashed line 51 the axis of rotation 15 and the dashed line 47 is 90 degrees. All angles between the center of rotation and enclosed between the dashed lines 47 and 51 are equal to 90 degrees. The dashed lines 48 and 49 represent the spaces between the segments.

Thus the present invention can be described as a material savings container cap comprising a circular flat top having a perimeter, an annular segmented container cap wall, each separated segment of container cap wall descending from a different portion of the perimeter of the top, the container cap wall having an internal screw thread design for interlocking in mating relationship with a container wall of a container neck wherein the angle of the internal threading to the container cap wall is between approximately thirty degrees and approximately forty-five degrees and wherein the internal screw thread always points towards the inner surface of the flat top of the container cap and towards an axis of rotation of the container cap.

The present invention also encompasses a combination of a material savings container cap and a container neck, the container cap being as described and the container neck having a container neck wall having an external screw thread design for interlocking in mating relationship with the internal screw thread design of the container cap wall and having an angle of the external threading to the container neck wall that is between approximately thirty degrees and approximately forty-five degrees and wherein the external screw thread always points away from the opening of the container and away from the axis of rotation of the container neck.

The above characteristics of the threading creates a ratchet type locking effect. Accordingly, the effective locking force of the material savings cap is just as great as the locking force of a cap having a continuous cylindrical container wall with no segments separated by spaces. The unique segment sizes and arrangements follow pre-determined patterns that conform to the mechanical demand of strength and aesthetics.

It is to be understood that while the apparatus of this invention have been described and illustrated in detail, the above-described embodiments are simply illustrative of the principles of the invention. It is to be understood also that various other modifications and changes may be devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof. It is not desired to limit the invention to the exact construction and operation shown and described. The spirit and scope of this invention are limited only by the spirit and scope of the following claims.

Claims

1. A material savings container cap comprising

a circular flat top having a perimeter,
an annular segmented container cap wall, each separated segment of container wall descending from a different portion of the perimeter of the top,
the container cap wall having an internal screw thread design for interlocking in mating relationship with a container wall of a container neck wherein an angle of an internal threading to the container cap wall is between approximately thirty degrees and approximately forty-five degrees.

2. The combination of a material savings container cap and a container neck,

the container cap having a circular flat top having a perimeter, an annular segmented container cap wall, each separated segment of container wall descending from a different portion of the perimeter of the top, the container cap wall having an internal screw thread design for interlocking with a container wall of the container neck wherein an angle of a threading to the container cap wall is between approximately thirty degrees and approximately forty-five degrees,
the container neck having a container neck wall having an external screw thread design for interlocking in mating relationship with the internal screw thread design of the container cap wall and having an angle of an external threading to the container neck wall that is between approximately thirty degrees and approximately forty-five degrees.

3. A material savings container cap comprising

a circular flat top having a perimeter,
an annular segmented container cap wall, each separated segment of container cap wall descending from a different portion of the perimeter of the top,
the container cap wall having an internal screw thread design for interlocking in mating relationship with a container wall of a container neck wherein an internal screw thread always points towards an inner surface of the flat top of the container cap and towards an axis of rotation of the container cap.

4. The combination of a material savings container cap and a container neck,

the container cap having
a circular flat top having a perimeter,
an annular segmented container cap wall, each separated segment of container cap wall descending from a different portion of the perimeter of the top,
the container cap wall having an internal screw thread design for interlocking in mating relationship with a container wall of a container neck wherein an internal screw thread always points towards an inner surface of the flat top of the container cap and towards an axis of rotation of the container cap,
the container neck having a container neck wall that has an external screw thread design for interlocking in mating relationship with the internal screw thread design of the container cap wall and wherein an external screw thread always points away from an opening of the container and away from an axis of rotation of the container neck.
Patent History
Publication number: 20060086688
Type: Application
Filed: Oct 21, 2004
Publication Date: Apr 27, 2006
Inventor: Nikolaus Tang-Lee (Gasparillo)
Application Number: 10/970,506
Classifications
Current U.S. Class: 215/44.000; 215/329.000; 215/321.000; 220/288.000
International Classification: B65B 7/28 (20060101); B65D 41/16 (20060101); B65D 41/04 (20060101);