HIGH SPEED NECKING CONFIGURATION
A horizontal can necking machine assembly includes a plural of main turrets and a plural of transfer starwheels. Each main turret includes a main turret shaft, a main gear mounted on the main turret shaft, a pusher assembly, and a die capable of necking a can body upon actuation of the turret shaft. Each transfer starwheel includes a transfer shaft and a transfer gear mounted on the transfer shaft. The main gears are engaged with the transfer gears such that lines through the main gear center and the centers of opposing transfer gears form an included angle of less than 170 degrees, thereby increasing the angular range available for necking the can body. The main turrets and transfer starwheels may operate to neck and move at least 2800 cans per minute, and each pusher assembly may have a stroke length relative to the die that is at least 1.5 inches.
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This application is a continuation of application Ser. No. 15/928,984, filed Mar. 22, 2018, which is a continuation of application Ser. No. 15/088,691, filed Apr. 1, 2016, which is a continuation of application Ser. No. 14/070,954, filed Nov. 4, 2013, now U.S. Pat. No. 9,308,570, which is a continuation of application Ser. No. 12/109,176, filed Apr. 24, 2008, now U.S. Pat. No. 8,601,843, and is related by subject matter to the inventions disclosed in the following commonly assigned applications: U.S. patent application Ser. No. 12/109,031, filed on Apr. 24, 2008 and entitled “Apparatus For Rotating A Container Body”, now issued U.S. Pat. No. 7,997,111, U.S. patent application Ser. No. 12/108,950 filed on Apr. 24, 2008 and entitled “Adjustable Transfer Assembly For Container Manufacturing Process”, now U.S. Pat. No. 8,245,551, U.S. patent application Ser. No. 12/109,058, filed on Apr. 24, 2008 and entitled “Distributed Drives for A Multi-Stage Can Necking Machine”, now U.S. Pat. No. 8,464,567, U.S. patent application Ser. No. 12/108,926, filed on Apr. 24, 2008 and entitled “Container Manufacturing Process Having Front-End Winder Assembly”, now U.S. Pat. No. 7,770,425, and U.S. patent application Ser. No. 12/109,131, filed on Apr. 24, 2008 and entitled “Systems And Methods For Monitoring And Controlling A Can Necking Process,” now U.S. Pat. No. 7,784,319. The disclosure of each application is incorporated by reference herein in its entirety.
FIELD OF THE TECHNOLOGYThe present technology relates to a multi-stage can necking machine. More particularly, the present technology relates to a horizontal multi-stage can necking machine configured for high speed operations.
BACKGROUNDMetal beverage cans are designed and manufactured to withstand high internal pressure—typically 90 or 100 psi. Can bodies are commonly formed from a metal blank that is first drawn into a cup. The bottom of the cup is formed into a dome and a standing ring, and the sides of the cup are ironed to a desired can wall thickness and height. After the can is filled, a can end is placed onto the open can end and affixed with a seaming process.
It has been conventional practice to reduce the diameter at the top of the can to reduce the weight of the can end in a process referred to as necking. Cans may be necked in a “spin necking” process in which cans are rotated with rollers that reduce the diameter of the neck. Most cans are necked in a “die necking” process in which cans are longitudinally pushed into dies to gently reduce the neck diameter over several stages. For example, reducing the diameter of a can neck from a conventional body diameter of 2-11/16th inches to 2-6/16th inches (that is, from a 211 to a 206 size) often requires multiple stages, often 14.
Each of the necking stages typically includes a main turret shaft that carries a starwheel for holding the can bodies, a die assembly that includes the tooling for reducing the diameter of the open end of the can, and a pusher ram to push the can into the die tooling. Each necking stage also typically includes a transfer starwheel shaft that carries a starwheel to transfer cans between turret starwheels.
Multi-stage can necking machines are limited in speed. Typically, commercial machines run at a rate of 1200-2500 cans per minute. While this is a high rate, there is a constant need to produce more and more cans per minute.
Also, concentricity of cans is important. A small misalignment at the beginning of the necking stages may result in concentricity problems between the can body and neck. For illustration, a difference in the centers of 0.020 inches (twenty thousandths) could result in a weak seam or even result in an insufficiently seamed can.
SUMMARYA horizontal can necking machine assembly may include a plural of main turrets and a plural of transfer starwheels. Each main turret may include a main turret shaft, a main gear mounted proximate to an end of the main turret shaft, a pusher assembly, and a die capable of necking a can body upon actuation of the turret shaft. Each transfer starwheel may include a transfer shaft and a transfer gear mounted proximate to an end of the transfer shaft. The transfer starwheels may be located in an alternating relationship with the main turrets, and the main gears may be engaged with the transfer gears such that lines through the main gear center and the centers of opposing transfer gears form an included angle of less than 170 degrees, thereby increasing the angular range available for necking the can body. The saw tooth configuration of turret and transfer shafts that provides this included angle yields, compared with configurations defining a 180 degree included angle, increased can residence time in the operational zone for a given rotational speed, which increased time enables longer or slower spindle stroke, and/or higher can throughput for a given residence time, or a combination thereof. In this regard, the main turrets and transfer starwheels may be operative to neck and move at least 2800 cans per minute, and each pusher assembly may have a stroke length relative to the die that is at least 1.5 inches, and preferably 3400 cans per minute at a stroke length of 1.75 inches.
A die for necking a can body may include a neck portion, a body portion, and a transition portion. The necking portion may have an inner wall that defines a cylinder having a first diameter. The body portion may have an inner wall that defines a cylinder having a second diameter. The transition portion may have an inner wall that smoothly transitions from the inner wall of the neck portion to the inner wall of the body portion. The first diameter is larger than the second diameter, and the neck portion is at least 0.125 inches long, and preferably 0.375 inches long.
A preferred configuration for driving a multi-stage can necking machine is provided. The multi-stage can necking machine incorporates technology that overcomes the many shortcomings of known multi-stage can necking machines. The present invention is not limited to the disclosed configuration, but rather encompasses use of the technology disclosed, in any manufacturing application according to the language of the claims.
As shown in
Die 34, in transverse cross section, is typically designed to have a lower cylindrical surface with a dimension capable of receiving the can body, a curved or angled transition zone, and a reduced diameter (relative to the lower cylindrical surface) upper cylindrical surface above the transition zone. During the necking operation, the can body is moved up into die 34 such that the open end of the can body is placed into touching contact with the transition zone of die 34. As the can body is moved further upward into die 34, the upper region of the can body is forced past the transition zone into a snug position between the inner reduced diameter surface of die 34 and a form control member or sleeve located at the lower portion of pusher ram 30. The diameter of the upper region of the can is thereby given a reduced dimension by die 34. A curvature is formed in the can wall corresponding to the surface configuration of the transition zone of die 34. The can is then ejected out of die 34 and transferred to an adjacent transfer starwheel. U.S. Pat. No. 6,094,961, which is incorporated herein by reference, discloses an example necking die used in can necking operations.
As best shown in
As shown in
As shown, a gear 62 (shown schematically in
As also shown in
Machine 10 may be configured with any number of necking stations 18, depending on the original and final neck diameters, material and thickness of can 72, and like parameters, as understood by persons familiar with can necking technology. For example, multi-stage can necking machine 10 illustrated in the figures includes eight stages 14, and each stage incrementally reduces the diameter of the open end of the can body 72 as described above.
As shown in
In this regard, for a given rotational speed, the longer residence time of a can in the operative zone enables a longer stroke length for a given longitudinal speed of the pusher ram. For example, with the above identified configuration, the pusher ram 30 may have a stroke length relative to the die 34 of at least 1.5 inches. Preferably, the pusher ram 30 will have a stroke length relative to the die 34 of at least 1.625 inches and even more preferably the stroke length is at least 1.75 inches. For the embodiment shown in the figures, the stroke length is approximately 1.75 inches.
The angular range available for necking of greater than 180 degrees enables the die used to reduce the diameter of the end of the can body to be designed to improve the concentricity of the can end. As shown in
To help improve the concentricity of the can end the throat portion preferably has a length of at least 0.125 inches, more preferably a length of at least 0.25 inches and even more preferably a length of at least 0.375 inches. The embodiment illustrated in the figures has a throat length of approximately 0.375 inches. Furthermore, an inlet 102 of the throat portion 78 may be rounded.
During operation of conventional stroke machines, the first part of the can that touches the die is the neck or necked rim. Any error in the neck portion often becomes worse, throughout the necking stages. In the long stroke machine illustrated herein, when the can goes into the die, it first locates itself in the die before it touches the transition portion. Therefore, by having a longer throat portion 78 compared with the prior art, the die 34 is able to center the can body prior to necking. Additionally, by having a longer throat portion 78, the die 34 is able to seal the compressed air sooner. Until the can is sealed, the compresses air blows into the ambient atmosphere, which can be costly.
Referring back to
Each motor 106 is driven by a separate inverter which supplies the motors 106 with current. To achieve a desired motor speed, the frequency of the inverter output is altered, typically between zero to 50 (or 60 hertz). For example, if the motors 106 are to be driven at half speed (that is, half the rotational speed corresponding to half the maximum or rated throughput) they would be supplied with 25 Hz (or 30 Hz).
In the case of the distributed drive configuration shown herein, each motor inverter is set at a different frequency. Referring to
The downstream motors preferably are preferably controlled to operate at a slightly higher speed to maintain contact between the driving gear teeth and the driven gear teeth throughout the gear train. Even a small freewheeling effect in which a driven gear loses contact with its driving gear could introduce a variation in rotational speed in the gear or misalignment as the gear during operation would not be in its designed position during its rotation. Because the operating turrets are attached to the gear train, variations in rotational speed could produce misalignment as a can 72 is passed between starwheel and main turret pockets and variability in the necking process. The actual result of controlling the downstream gears to operate a slightly higher speed is that the motors 120, 124, and 128 all run at the same speed, with motors 120 and 128 “slipping,” which should not have any detrimental effect on the life of the motors. Essentially, motors 120 and 128 are applying more torque, which causes the gear train to be “pulled along” from the direction of motor 128. Such an arrangement eliminates variation in backlash in the gears, as they are always contacting on the same side of the tooth, as shown in
In the case of a machine using one motor, reductions in speed may cause the gears to drive on the opposite side of the teeth. It is possible that this may create small changes in the relationship between the timing of the pockets passing cans from one turret to the next, and if this happens, the can bodies may be dented.
The present invention has been described by illustrating preferred embodiments. The present invention is not limited to an configuration or dimensions provided in the specification, but rather should be entitled to the full scope as defined in the claims.
Claims
1. (canceled)
2. A horizontal beverage can necking machine assembly for forming necked beverage can bodies suitable for forming a seam with a beverage can end, the assembly comprising:
- multiple horizontal necking stages adapted for necking at least 3000 beverage can bodies per minute, each necking stage being configured to rotate about a respective axis that is substantially parallel to a surface on which the necking machine is supported;
- longitudinal centers of adjacent necking stages forming an included angle with the longitudinal center of a transfer starwheel, measured with the longitudinal center of the transfer starwheel at the vertex, of no more than 170 degrees;
- each one of the necking stages including a main turret that includes: a main turret shaft, a main turret starwheel having plural pockets adapted for carrying can bodies, and a main gear in mesh communication with a transfer starwheel gear;
- each one of the pockets having a necking die at one end thereof and a pad on an opposing end;
- each necking die of each one of the necking stages comprising: a throat portion that is at least 0.125 inches long; a body portion having an inner dimension that is smaller than an inner dimension of the throat portion; and a transition portion having an inner surface that smoothly transitions from an inner surface of the throat portion to an inner surface of the body portion; and
- each one of the pockets of each one of the necking stages having a first configuration in which the can body is spaced apart from the necking die and a second configuration in which the can body is engaged with the necking die;
- in the first configuration the pad is spaced apart from the necking die by a first distance, in the second configuration the pad is spaced apart from the necking die by a second distance that is at least 1.5 inches less than the first distance.
3. The necking machine assembly of claim 2 wherein the throat portion inner surface defines a cylinder having a diameter that is the throat portion inner dimension, the body portion inner surface defines a cylinder having a diameter that is the body portion inner dimension.
4. The necking machine assembly of claim 2 wherein the second distance is at least 1.625 inches less than the first distance.
5. The necking machine assembly of claim 2 wherein the second distance is at least 1.75 inches less than the first distance.
6. The necking machine assembly of claim 2 wherein the necking stages are adapted for necking at least 3200 beverage can bodies per minute.
7. The necking machine assembly of claim 2 wherein the necking stages are adapted for necking at least 3400 can bodies per minute.
8. The necking machine assembly of claim 2 wherein the throat portion of each necking die is at least 0.25 inches long.
9. The necking machine assembly of claim 2 wherein the throat portion of each necking die is at least 0.375 inches long.
10. The necking machine assembly of claim 2 wherein the pad is part of a pusher assembly adapted for moving the pad toward the necking die.
11. The necking machine assembly of claim 2 wherein the included angle is no more than 120 degrees.
12. A horizontal beverage can necking machine for forming necked beverage can bodies suitable for forming a seam with a beverage can end, the horizontal necking machine including multiple operation stages, at least some of the operation stages comprising:
- multiple horizontal necking stages adapted for necking at least 3000 beverage can bodies per minute, each necking stage being configured to rotate about a respective axis that is substantially parallel to a surface on which the necking machine is supported;
- longitudinal centers of adjacent necking stages forming an included angle with the longitudinal center of a transfer starwheel, measured with the longitudinal center of the transfer starwheel at the vertex, of no more than 170 degrees;
- each one of the necking stages including a main turret that includes: a main turret shaft, a main turret starwheel having plural pockets adapted for carrying can bodies, and a main gear adapted for receiving torque to rotate the main turret shaft; each one of the pockets having a necking die at one end thereof and a pad on an opposing end;
- each necking die comprising: a throat portion having an inner surface that defines a cylinder having a throat portion diameter; a body portion having an inner surface that defines a cylinder having a body portion diameter; and a transition portion having an inner surface that smoothly transitions from the inner surface of the throat portion to the inner surface of the body portion, wherein the throat portion diameter is larger than the body portion diameter; and
- each one of the pockets of each one of the necking stages having a first configuration in which the can body is spaced apart from the necking die and a second configuration in which the can body is engaged with the necking die; in the first configuration the pad is spaced apart from the necking die by a first distance, in the second configuration the pad is spaced apart from the necking die by a second distance that is at least 1.75 inches less than the first distance;
- whereby the throat portion inner surface is adapted for enhancing concentricity of the can body relative to the die.
13. The horizontal beverage can necking machine of claim 12 wherein the longitudinal centers of the adjacent necking stages form the included angle with the longitudinal center of the transfer starwheel of no more than 120 degrees.
14. The horizontal beverage can necking machine of claim 12 wherein the pad is part of a pusher assembly adapted for moving the pad toward the necking die.
15. The horizontal beverage can necking machine of claim 12, wherein the throat portion is at least 0.25 inches long.
16. The horizontal beverage can necking machine of claim 15 wherein the included angle of no more than 120 degrees thereby increases the angular range available for necking the can body.
17. The horizontal beverage can necking machine of claim 16 wherein the necking stages are adapted for necking at least 3200 beverage can bodies per minute.
18. The horizontal beverage can necking machine of claim 16 wherein the necking stages are adapted for necking at least 3400 beverage can bodies per minute.
19. The horizontal beverage can necking machine of claim 12, wherein the throat portion is approximately 0.375 inches long.
20. The horizontal beverage can necking machine of claim 19 wherein the included angle of no more than 120 degrees thereby increases the angular range available for necking the can body.
21. The horizontal beverage can necking machine of claim 20 wherein the necking stages are adapted for necking at least 3200 beverage can bodies per minute.
22. The horizontal beverage can necking machine of claim 20 wherein the necking stages are adapted for necking at least 3400 beverage can bodies per minute.
23. The horizontal can necking machine of claim 12 wherein the pad is adapted for being moved toward the necking die.
24. The horizontal beverage can necking machine of claim 12 wherein the necking stages are adapted for necking at least 3200 beverage can bodies per minute.
25. The horizontal beverage can necking machine of claim 12 wherein the necking stages are adapted for necking at least 3400 beverage can bodies per minute.
26. The horizontal beverage can necking machine of claim 12 wherein for each necking stage the main gear is mounted on the main turret shaft.
27. The horizontal beverage can necking machine of claim 12, wherein the throat portion is rounded proximate to an inlet of the throat portion.
28. The horizontal beverage can necking machine of claim 12, wherein the operation stages further include an input station.
29. The horizontal beverage can necking machine of claim 12, wherein the operation stages further include a bottom reforming station.
30. The horizontal beverage can necking machine of claim 12, wherein the operation stages further include a flanging station.
31. The horizontal beverage can necking machine of claim 12, wherein the operation stages further include a light-testing station.
32. The horizontal beverage can necking machine of claim 12, wherein the operation stages further include at least one of an input station, a bottom reforming station, a flanging station and a light-testing station.
Type: Application
Filed: Oct 6, 2023
Publication Date: Feb 29, 2024
Applicant: Crown Packaging Technology, Inc. (Tinley Park, IL)
Inventors: Paul Robert Dunwoody (Oxfordshire), Ian K. Scholey (Tankersley)
Application Number: 18/377,470