Collapsible sawhorse

Abstract

A support structure has a first leg, a second leg, eg, a second leg, a third leg and a fourth leg. Each of these legs has a top portion, a center portion, and a bottom portion. The first leg includes a first hinge and a first stop. The first hinge connects the first leg center portion and the second leg center portion. The first hinge allows rotation of the second leg with respect to the first leg. The first leg center portion includes the first stop for limiting the rotation of the second leg with respect to the first leg.

Description

RELATED APPLICATIONS

This patent application claims the benefit of Provisional Patent Application 60/880,128, filed Jan. 12, 2007 and entitled “Collapsible Sawhorse,” incorporated herein by reference.

FIELD

This patent application generally relates to a structure for supporting a work piece. More particularly it relates to a sawhorse that is easily adjustable in height and that collapses for storage and transportation.

BACKGROUND

A traditional sawhorse is used for supporting a work piece either by itself or in conjunction with another sawhorse. The traditional sawhorse usually takes on an A-frame structure and is generally rigid with a fixed height. The rigidness of the sawhorse means it takes up substantial space and is hard to transport and move compactly. The fixed height of the sawhorse makes it less accommodating to people of varying height. The fixed height also does not allow for ease of use in jobs where being able to vary the work height maybe of benefit. Some sawhorse designs have had legs that could be disassembled or folded. Others have had extendable legs. Although past designs offer some degree of improvement over the traditional rigid sawhorse, there exists a need for a stable sawhorse that is fully collapsible, has adjustable height, is easy to set up and take down, and is very sturdy when in use. Thus, improved saw horse designs are needed, and embodiments of such designs are provided in the present patent application.

SUMMARY

One aspect of the present patent application is a support structure, comprising a first leg, a second leg, a third leg and a fourth leg. Each of these legs has a top portion, a center portion, and a bottom portion. The first leg includes a first hinge and a first stop. The first hinge connects the first leg center portion and the second leg center portion. The first hinge allows rotation of the second leg with respect to the first leg. The first leg center portion includes the first stop for limiting the rotation of the second leg with respect to the first leg.

Another aspect of the present patent application is a support structure, comprising a first leg, a second leg, a third leg and a fourth leg. Each of these legs has a top portion, a center portion, and a bottom portion. The first leg center portion overlaps the second leg center portion. The third leg center portion overlaps the fourth leg center portion. The first leg has a first width in the first leg center portion. The first leg has a second width outside the first leg center portion. The first width is greater than the second width.

Another aspect of the present patent application is a support structure, comprising a first leg, a second leg, a third leg and a fourth leg. Each of these legs has a top portion, a center portion, and a bottom portion. The support structure also includes a first hinge and a second hinge. The first hinge connects the first leg center portion and the second leg center portion while the second hinge connects the third leg center portion and the fourth leg center portion. The first hinge allows rotation of the second leg with respect to the first leg while the second hinge allows rotation of the forth leg with respect to the third leg. The first leg center portion and the second leg center portion are mortised and the third leg center portion and the fourth leg center portion are mortised.

Another aspect of the present patent application is a support structure, comprising a first leg, a second leg, a third leg and a fourth leg. Each of these legs has a top portion, a center portion, and a bottom portion. The support structure also includes a bar and a hinge. The hinge extends between the first leg and the second leg. The hinge extends through the bar. The hinge includes a device having a variable length.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following detailed description as illustrated in the accompanying drawings, for clarity not drawn to scale, in which:

FIG. 1a is a front three dimensional view of a structure according to one embodiment of the present patent application illustrating two scissor sides and a horizontal top member for supporting a piece of work;

FIG. 1b is a side three dimensional view of the structure in FIG. 1a;

FIG. 2a is a right side view of the structure in FIG. 1a fully collapsed;

FIG. 2b is a front view of the structure in FIG. 1a fully collapsed;

FIG. 2c is a left side view of the structure in FIG. 1a fully collapsed;

FIG. 3a is a cut away, three dimensional view of one embodiment of part of an elongate structure hinge assembly that includes a pin and a spring used to connect components of the collapsible sawhorse;

FIG. 3b is a side view of the hinge assembly of FIG. 3a connecting components of the collapsible sawhorse;

FIG. 3c is a side view of the saw horse in open position looking toward the end with the elongate structure hinge assembly of FIG. 3a;

FIG. 3c is a side view of the saw horse in closed position looking toward the end with the elongate structure hinge assembly of FIG. 3a;

FIG. 4a is another front view of the structure of FIG. 1a in the fully collapsed state;

FIG. 4b is a front view of the structure in FIG. 4a with the scissor sides open and the horizontal top member rotated out of its locked position;

FIG. 4c is a front three dimensional view of the structure in FIG. 4b with the scissor sides extended and the horizontal top member locked into place;

FIG. 4d is a front view of the structure in FIG. 4c showing details of the locking of the horizontal top member to one of the hinges of the saw horse;

FIG. 5a is a front three dimensional view of the structure for supporting a piece of work set to a first height;

FIG. 5b is a front three dimensional view of the structure in FIG. 5a set to a second height;

FIG. 6 is a three dimensional view of the structure in FIG. 5a showing various ways of using the structure to support a piece of work;

FIG. 7a is an exploded three dimensional view of two legs of one scissor side of the structure of FIG. 1 showing details of their hinged connection; and

FIG. 7b is a three dimensional view of the legs of FIG. 7a when connected to each other at the hinge connection.

DETAILED DESCRIPTION

One embodiment of sawhorse 10 includes first scissor side 12, second scissor side 14 and horizontal top member 16, as shown in FIGS. 1a and 1b. First scissor side 12 includes a pair of crossed leg members 18 and 20. Crossed leg members 18 and 20 include top portions 18t, 20t, center portions 18c, 20c, and bottom portions 18b, 20b. Crossed leg members 18 and 20 are joined together by hinge 22 in center portions 18c, 20c, which is near the midpoint of each leg member 18, 20.

Similarly, second scissor side 14 includes a pair of crossed leg members 24 and 26 with the crossed leg members joined together in region 27 by hinge 28, which is near the midpoint of each leg member 24, 26.

Top ends 18t and 20t of first scissor side 12 are connected to top ends 26t and 24t of second scissor side 14 at first hinge 30 and second hinge 32, respectively. Hinges 30 and 32 allow bottom ends 18b, 20b, 24b and 26b of cross legged members 18, 20, 24 and 26 to be spread apart to generate a stable support structure.

Spreading apart of bottom ends 18b, 20b, 24b and 26b is limited to an angle at which top ends 18t, 20t, 24t, 26t press against horizontal top member 16. Cable 33 connects between hinge 22 and hinge 28 to also limit the amount of spreading between each scissor side 12, 14.

In this embodiment, hinge 30 includes elongated structure 31, as shown in FIGS. 3a, 3c, and 3d, that passes through horizontal top member 16 at end 16a. Horizontal top member 16 can rotate around elongated structure 31, as shown in FIGS. 4b, 4c. End 16b of horizontal top member 16 is fitted with notch 34 that rests on hinge 32. Several notches 34 can be provided, allowing sawhorse 10 to have a variable height.

Traction bumps 36 may be provided on the angled portions 37 of bottom ends 18b, 20b, 24b and 26b of crossed legs 18, 20, 24, 26, as shown in FIGS. 1a, 2b. A stable structure for supporting a piece of work is created when crossed legs 18, 20 and crossed legs 24 and 26 are spread apart parallel to horizontal top member 16 and when bottom ends 18b, 20b of scissor sides 12 and bottom ends 24b and 26b of scissor sides 14 are also spread apart perpendicular to horizontal top member 16.

Crossed leg members 18, 20, 24 and 26 may be fabricated from a laminated wood material, plastic, steel or any other rigid material such as fiberglass, aluminum, titanium, and carbon composite materials. They may be fabricated with elongated holes 38 or similar cut away structures to help reduce the weight of sawhorse 10, still providing it with strength and rigidity. Elongated holes 38 or similar grooved structures also act to aid the user in grasping or carrying sawhorse 10.

Hinges 22 and 28 may be bolts. Hinges 22 and 28 may be made of the same material as the crossed leg members. Hinges 22 and 28 can also be made of a different one of these materials that provides lower friction for pivoting. Hinges 22 and 28 can also be molded integrated in a single piece with crossed leg members 18, 20, and 24, 26, and one or more materials can be used for the leg and hinge portions of this molded integrated component. Hinges 22 and 28 may also include a nylon washer where center portion 18c of leg member 18 makes contact with center portion 20c of leg member 20 and where center portion 24c of leg member 24 makes contact with center portion 26c of leg member 26 to reduce friction.

Horizontal member 16 may also be fabricated from wood, plastic, steel or any other rigid material. Horizontal member 16 may also be fitted with a surface that is replaceable if it is cut or worn.

In one embodiment horizontal member 16 is a 2×4 piece of lumber that rests on both hinges and is not connected to sawhorse 10 with hinge 30. To be used in this embodiment hinge 30 is not needed and a hinge like hinge 32 may be used instead. In this embodiment the sawhorse may open to a height defined by a stop integrated in hinges 22 and 28, as shown in FIG. 7 and described herein below. The 2×4 serves to limit the spreading of scissor sides 12 and 14 perpendicular to the 2×4. The 2×4 can be removed and stored separately before collapsing the sawhorse.

In one embodiment, sawhorse 10 includes male spacer 27 and female spacer 29 located on the inner sides of hinges 28 and 22, as shown in FIGS. 1a, 1b and 2a. Female spacer 29 is located and designed to receive male spacer 27. In one embodiment, in the collapsed state of sawhorse 10, male spacer 27 fits within female spacer 29. Spacers 27, 29 stop top member 16 from swinging back and forth past hinges 22, 28 during the process of collapsing sawhorse 10. Also when engaged, spacers 27, 29 limit the amount of twist that can occur in sawhorse 10 in the collapsed state.

When crossed leg members 18, 20, 24, 26 are rotated to provide zero angle between legs 18 and 20 and between legs 24 and 26 and when bottom ends 18b, 20b of scissor sides 12 and bottom ends 24b and 26b of scissor sides 14 are pushed together, sawhorse 10 will be in a closed or fully collapsed state, as shown in FIGS. 2a-2c. Here each pair of crossed legged members 18, 20 and 24, 26 are collapsed parallel to each other. Hinge 30 still passes through first end 16a of top member 16. Horizontal top member 16 can be rotated clockwise around hinge 30 to also lie parallel to crossed leg members 18, 20 and 24, 26 between two collapsed scissor legs 12, 14. Spacers 27, 29 prevent horizontal top member 16 from swinging through, and hinges 30, 32 provide for enough width to allow horizontal top member 16 to fit between collapsed scissor sides 12 and 14. In this collapsed state, hinge 30 and hinge 32 are adjacent each other.

Leg members 18, 20, 24 and 26 have tapered angles 40 at top ends 18t, 20t, 24t and 26t, as shown in FIGS. 2a, 2c, to accommodate the desired amount of spreading that will occur when bottom ends 18b, 20b of scissor sides 12 and bottom ends 24b and 26b of scissor sides 14 are spread apart. The taper of angles 40 is typically around 20 degrees. When bottom ends 18b, 20b, 24b, and 26b of scissor sides 12, 14 are spread apart, tapered top ends 18t, 20t, 24t and 26t press against horizontal top member 16 preventing further spreading of bottom ends 18b, 20b, 24b, and 26b.

Multiple notches 34a-c are provided in the bottom of horizontal member 16 to allow for multiple height adjustments, as shown in FIGS. 1a, 2b, and 4b. Retaining strap 42 is used to hold all pieces of sawhorse 10 tightly together when in the collapsed state, as shown in FIGS. 2a-2c. Horizontal member 16 may also have a hanging hole 44 to allow for hanging of sawhorse 10 on a wall when in the collapsed state, as shown in FIG. 2b.

Sawhorse 10 folds to a fraction of its open or in-use size when it is in its closed or collapsed state. For example, when open the rectilinear volume may be 23.5 inches wide by 30.5 inches long by 29.5 inches high, or a volume of 21,144 cubic inches. In the collapsed state, the same sawhorse 10 has dimensions of 4 inches wide by 5.5 inches long by 46 inches high, or 1,012 cubic inches. This is a 21-to-1 volume reduction.

Hinge 30 flexibly connects top ends 20t and 26t of leg members 20 and 26 together while allowing bottom ends 20b, 26b to be spread apart, as shown in FIGS. 3c, 3d. Hinge 30 extends through end 16a of horizontal top member 16, supporting end 16a of horizontal top member 16 and allowing horizontal top member 16 to rotate around axis 45 of hinge 30. Hinge 30 has a variable length L sufficient to provide spacing between top ends 20t and 26t of leg members 20 and 26 for horizontal top member 16 to fit between scissor sides 12 and 14 when sawhorse 10 is collapsed.

Elongated structure 31 of hinge 30 includes pin 46a, large coiled spring 46b, small springs 46c, and washer 46d, as shown in FIG. 3a. Large coiled spring 46b makes length of elongated support structure 31 adjustable to accommodate variations in the angular spacing between scissor sides 12 and 14 when saw horse 10 is set for different heights or is collapsed for storage.

Both ends of coiled spring 46b have looped ends 48 that extend beyond pin 46a all the way through holes 47 in top ends 20t and 26t of leg members 20 and 26 respectively and through the hole of washer 46d. Winged locking pins or S hooks 50 extend though looped ends 48 of coiled spring 46b and hold coiled spring 46b in place through top ends 20t and 26t of leg members 20 and 26, as shown in FIGS. 3a, 3b.

Top ends 20t and 26t of leg members 20 and 26 can have slots 54 where looped ends 48 of coiled spring 46b reside, as shown in FIG. 3b. Slots 54 allow for hinge 30 to adjust for optimal positioning when crossed legs 18, 20, 24, 26 are in either the open or collapsed state. Slot 54 allows coiled spring 46b to move up and down, providing give so sawhorse 10 can be set on a surface having up to ¾ inch of unevenness. Slot 54 also provides so extra space facilitating opening and closing of leg members 20, 26.

Pin 46a lies within coiled spring 46b and provides support for horizontal top member 16 on top ends of legs 20t and 26t when saw horse 10 is in use in its open position, as shown in FIG. 3c. AS saw horse 10 is closed, pin 46a pulls out of holes 47 in top ends 20t, 26t of leg members 20, 26 allowing legs 20, 26 to rotate, as shown in FIG. 3d. Coiled spring 46b expands and continues to extend through holes 47 retaining pin 46a in position for later reopening saw horse 10. Pin 46a is also held in position by small springs 46c that fit inside coiled spring 46b and keep pin 46a centered within top member 16. Small springs 46c are in compression mode between pin 46a and washer 46d.

Flex provided by coiled spring 46b allows for cross legs 20, 26 to adjust for any uneven ground. Coiled spring 46b is always under tension so it is always pulling top ends 20t, 26t of legs members 20, 26 together and toward top member 16. Spring tension in coiled spring 46b adds to pressure provided by top ends 20t, 26t pinching horizontal top member 16 when bottom ends 18b, 20b, 24b, 26b of crossed legs 18, 20, 24, 26 are spread apart. The stiffness of spring 46b of hinge 30 sets the amount of this contributor to pinching.

Sawhorse 10 is set up from the collapsed state as shown in FIGS. 4a-c. First, retaining strap 42 is opened, as shown in FIG. 4a. Top ends 18t and 20t of scissor legs 12 and top ends 24t and 26t of scissor legs 14 are then pushed apart parallel to horizontal top member 16 to expand saw horse 10, as shown in FIG. 4b. During this process, horizontal top member 16 is rotated counterclockwise around hinge 30, as also shown in FIGS. 4b, 4c until one of notches 34a-34c engages with hinge 32, as shown in more detail in FIG. 4d. Bottoms of scissor legs 12 and 14 are then spread apart perpendicular to horizontal top member 16 until stopped by pressure of top ends 18t, 20t, 24t, 26t against horizontal top member 16. Retaining cable 33 may also restrain spreading apart of scissor legs. Height of sawhorse 10 is adjusted by adjusting which notch 34a-34c engages with hinge 32. Sawhorse 10 is now fully assembled and ready to be used to support a work piece. To collapse sawhorse 10, these steps are carried out in reverse.

Sawhorse 10 can be set to different working heights, as shown in FIGS. 5a, 5b. To adjust the height of sawhorse 10, the user first assembles the sawhorse as described in the preceding paragraph to height H1. Then to raise sawhorse 10 to height H2, the user disengages notch 34a of horizontal top member 16 from hinge 32 by lifting horizontal top member 16 and pivoting it slightly upward around hinge 30. Top ends 18t and 20t of cross legs 18 and 20 are brought a small amount closer together parallel to horizontal top member 16, as are top ends 24t and 26t of cross legs 24 and 26. This action increases the height of the “X” structure. Horizontal top member 16 is then pivoted back in place to engage one of the alternative notches 34b or 34c with hinge 32. The height of sawhorse 10 may now be lowered by lifting horizontal top member 16 off of notch 34b or 34c, spreading the cross leg structure parallel to horizontal top member 16 to lower the height of the “X” structure and engaging, for example, notch 34a with hinge 32.

A board, pipe or similar piece of work may be directly placed on top of horizontal top member 16, as shown in FIG. 6. Two sawhorses 10 may be used to support long work pieces. Recess 56 may be fabricated into horizontal top member 16 to securely hold two-by-four 58 in a particular place. Working material, such as board 60 may be stored below horizontal top member within the “X” structure created by crossed leg members 18, 20, 24 and 26.

Hinge 22 includes overlapping regions 70, 70′ of central parts 18c, 20c of legs 18, 20, as shown in FIG. 7. Hole 72, 72′ extends through the center of regions 70, 70′ and hinge 22 extends through hole 72 to provide a pivot around which leg 18 can rotate with respect to leg 20. Hinge 22 can be integral with region 70′ of leg 18 or it can be a separate piece, such as a bolt, that extends through holes 72, 72′ in overlapping regions 70, 70′.

Stops 74a, 74b are located on two sides of region 70 of leg 20 and identical stops 74a′, 74b′ are located on corresponding sides of region 70′ of leg 18. Thus, legs 18, 20 can rotate around hinge 22 until these stops 74a, 74b, 74a′, 74b′ meet, preventing further rotation, as shown in FIG. 7b. Mortising overlapping regions 70, 70′ of legs 18, 20 facilitates forming stops 74a, 74b, 74a′, 74b′. Mortising can be provided by sizing legs 18, 20 in overlapping region 23 to be half the thickness of legs 18, 20 in other regions.

In one embodiment a nylon bushing having an area about equal to that of region 70 is placed between regions 70, 70′ to reduce friction there between. Leg 18 is thus free to rotate with respect to leg 20 from an angle in which top and bottom parts of leg 18 are parallel to leg 20 and side portions of legs 18 and 20 are touching each other, as shown in FIGS. 3a-3c, to an angle determined by the location of stops 74a, 74b on leg 20 and complementary stops 74a′, 74b′ on leg 18. A similar arrangement provides hinge 28 on central parts 24c, 26c of legs 24, 26.

Leg 20 has a significantly larger width Wc in region 70 of hinge 22 than the width Wb it has outside region 70, for example toward bottom end 20b of leg 20, as shown in FIG. 7a. Typically, Wc is about two times Wb. While leg 20 is free to rotate through a substantial angle with respect to leg 18 overlap region 70,70′ does not much change in area as angle changes.

In addition to construction materials, such as lumber and pipes, the workpiece supported by sawhorse 10 can, for example, be a table top, an appliance, or a display counter.

While the disclosed methods and systems have been shown and described in connection with illustrated embodiments, various changes may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A support structure, comprising:

a first leg, a second leg, a third leg and a fourth leg, wherein each said leg has a top portion, a center portion, and a bottom portion; and

a first hinge and a first stop, said first hinge connecting said first leg center portion and said second leg center portion, wherein said first hinge allows rotation of said second leg with respect to said first leg, wherein said first leg center portion includes said first stop for limiting said rotation of said second leg with respect to said first leg.

2. A support structure, as recited in claim 1, further comprising a second hinge connecting said third leg center portion and said fourth leg center portion, said second hinge allowing rotation of said fourth leg with respect to said third leg.

3. A support structure, as recited in claim 2, wherein said third leg center portion includes a third stop for limiting said rotation of said fourth leg with respect to said third leg.

4. A support structure, as recited in claim 2, further comprising a third hinge located between said top portion of said first leg and said top portion of said third leg.

5. A support structure, as recited in claim 4, further comprising a fourth hinge located between said top portion of said second leg and said top portion of said fourth leg.

6. A support structure, as recited in claim 5, further comprising a bar extending between said top portions of said first and second legs, wherein pressure of said top portions of said first leg and said second leg pressing against said bar limits rotation of said first leg and said second leg around said third hinge.

7. A support structure, as recited in claim 6, wherein said first leg, said second leg, said third leg, and said fourth leg provide a stable structure when said first leg and said second leg have rotated to said first stop and when said top portions of said first leg and said second leg have rotated toward top portions of said third leg and said fourth leg to provide said pressure.

8. A support structure, as recited in claim 6, wherein said fourth hinge extends through said bar, wherein said fourth hinge includes a variable spacing device.

9. A support structure, as recited in claim 8, wherein said variable spacing device includes a spring and a pin hinge.

10. A support structure, as recited in claim 2, wherein said first hinge includes a structure that extends toward said second hinge.

11. A support structure, as recited in claim 10, wherein said second hinge includes a structure that extends toward said first hinge.

12. A support structure, as recited in claim 1, further comprising a second stop, wherein said second leg center portion includes said second stop for limiting said rotation of said first leg with respect to said second leg.

13. A support structure, as recited in claim 12, wherein said first stop limits rotation of said second leg with respect to said first leg at about the same rotational angle that said second stop limits rotation of said first leg with respect to said second leg.

14. A support structure, as recited in claim 1, wherein said first leg has a first width in said first leg center portion and wherein said first leg has a second width outside said first leg center portion, wherein said first width is greater than said second width.

15. A support structure, as recited in claim 14, wherein said second leg has a third width in said second leg center portion and wherein said second leg has a fourth width outside said second leg center portion, wherein said first width is identical to said third width and wherein said second width is identical to said fourth width.

16. A support structure, as recited in claim 1, wherein said first leg, said second leg, said third leg, and said fourth leg are identical.

17. A support structure, as recited in claim 1, further comprising a bushing, wherein said bushing is located between said first leg center portion and said second leg center portion for reducing friction there between when said second leg rotates with respect to said first leg.

18. A support structure, as recited in claim 1, wherein said first leg center portion includes a first mortis and wherein said second leg center portion includes a second mortis, wherein said first mortis connects with said second mortis, wherein said first mortis includes a first edge, wherein said first edge provides said first stop.

19. A support structure, comprising a first leg, a second leg, a third leg and a fourth leg, wherein each said leg has a top portion, a center portion, and a bottom portion, wherein said first leg center portion overlaps said second leg center portion and wherein said third leg center portion overlaps said fourth leg center portion, wherein said first leg has a first width in said first leg center portion, and wherein said first leg has a second width outside said first leg center portion, wherein said first width is greater than said second width.

20. A support structure, comprising:

a first leg, a second leg, a third leg and a fourth leg, wherein each said leg has a top portion, a center portion, and a bottom portion; and

a first hinge and a second hinge, said first hinge connecting said first leg center portion and said second leg center portion, said second hinge connecting said third leg center portion and said fourth leg center portion, wherein said first hinge allows rotation of said second leg with respect to said first leg, wherein said second hinge allows rotation of said forth leg with respect to said third leg, wherein said first leg center portion and said second leg center portion are mortised and wherein said third leg center portion and said fourth leg center portion are mortised.

21. A support structure, comprising:

a first leg, a second leg, a third leg and a fourth leg, wherein each said leg has a top portion, a center portion, and a bottom portion;

a bar and a hinge, wherein said hinge extends between said first leg and said second leg, wherein said hinge extends through said bar, wherein said hinge includes a device having a variable length.

22. A support structure, as recited in claim 21, wherein said variable spacing device includes a spring and a pin, wherein said spring is longer than said pin.

23. A support structure, as recited in claim 21, further comprising a slot in said first leg and in said second leg, wherein said variable length device extends through said slot.