GB1600598A

GB1600598A - Mechanism for producing in sequence a rotational and translational movement of a member

Info

Publication number: GB1600598A
Application number: GB998277A
Authority: GB
Original assignee: Alcan Ekco Ltd
Current assignee: Alcan Ekco Ltd
Priority date: 1977-03-09
Filing date: 1977-03-09
Publication date: 1981-10-21
Also published as: JPS53131191A

Description

(54) MECHANISM FOR PRODUCING IN SEQUENCE MML A ROTATIONAL AND TRANSLATIONAL MOVEMENT OF A MEMBER (71) We, ALCAN EKCO LIMITED, a British Company, of 90 Asheridge Road, Chesham, Buckinghamshire HP5 2QE, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a mechanism for producing in sequence a rotational and a translational movement of a member and has a par.

ticularly useful but not exclusive application in a mechanism for taking a lid from the bottom of a stack of lids and placing it on a container.

According to this invention there is provided a mechanism comprising a rack mounted for guided movement lengthwise of itself, a gear element in mesh with the rack and rotatably mounted on a support, a driven member connected to the gear element for rotational and translational movement therewith, means for moving the support of the gear element lengthwise of the rack, a first abutment for limiting movement of the gear element relative to the rack in one direction along the rack, a second abutment for limiting said guided movement of the rack in said one direction, and means biasing the rack into a predetermined position spaced from the second abutment.

In a preferred construction according to the invention, the mechanism comprises a third abutment for limiting movement of the gear element relative to the rack in the opposite direction to said one direction, a fourth abutment for limiting said guided movement of the rack in said opposite direction, and means biasing the rack into said predetermined position away from said fourth abutment, said predetermined position of the rack being between the second and fourth abutments.

In a particular application of the invention the driven member comprises a frame having suction cups mounted thereon and the length of the rack traversed by the gear element between the first and third abutments is selected so as to rotate the frame through 180 . At each end of such rotation, continued movement of the gear element by said means for moving the support causes the gear element and rack to move together, without rotation of the gear element and hence of said frame, until the movement of the rack is limited by the second or fourth abutment according to the direction of the movement by the jack means.

One embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a diagrammatic elevation of a mechanism according to the invention, Figure 2 is a side elevation of the member operated by the mechanism, and Figure 3 is an elevation of the member illustrating its operation.

Referring first to Figure 3 of the drawings, the mechanism is designed to actuate operation of a member 10 for taking a lid 11 from the bottom of a stack 12 of lids, turning the lid upside down and depositing it in a rebate 13 round the upper edge of a container 14. In this case the container is made from aluminium foil.

The lids, which are made from stiff card with a layer of aluminium foil on their side which is to be presented to the container, are rectangular with rounded corners and are disposed with their foil side uppermost in the stack 12, which is bounded by vertical rods 15. The stack is supported by several strips 16 which are secured to the frame supporting the rods 15 and which have their inner edges underlying the edges of the sides of the lids.

The member 10 comprises a support arm 20 fixed to a shaft 21 and having two laterallyprojecting hinge elements 22 pivoted thereto about a pivot pin 23. Each hinge element has a laterally projecting portion 22a which carries a suction cup 24. The portions 22a of the hinge elements are interconnected by a double-acting pneumatic piston-and-cylinder motor 25 connected between brackets 22b on the portions 22a. Motor 25 when contracted, causes the portions 22a to take up a first position in which the cups are disposed in a common plane as shown in the upper part of Figure 3 and, when extended, pivots the portions 22a relative to the arms 20 to cause the cups to incline towards each other as shown in the lower part of Figure 3.Whilst the cups are in the first position the member 10 is moved towards the bottom lid 11 in the stack and the interior of each cup is automatically placed by a valve (not shown) in communication with a vacuum source by way of a connection 24a, so that the bottom lid becomes attached to the cups. The member is then first drawn straight downward, and then rotated through 1800, and is then moved straight down again to its second position close to the container. The vacuum in the cups is then automatically released by the valve, so that the lid is released in the recess. The pivotal movement of the portions 22a which has occurred during the downward movement bends the lid resiliently into the form shown.In effect the lid is shortened by this bending and this facilitates placing the lid in its recess on the container and enables the lid to be placed even when, as is commonplace, the edge flanges of the container have become slightly damaged.

Additionally the bending causes the rounded corners of the lid to form a lead-in for them into the rebate 13.

Referring now to Figure 1, the mechanism is shown by which the upward and downward movements and 1800 rotations of the member 10 are actuated automatically. The shaft 21 on one end of which the support arm 20 is fixed has fixed on its other end a toothed pulley 30, and the shaft is carried in bearings on a rod 31 which constitutes the support for the pulley and which is guided for vertical sliding movement in a sleeve 32 mounted on a fixed part 33 of the mechanism. The lower end of rod 31 has an eye 35 for pivotal connection to a lifting and lowering arm (not shown). The toothed pulley 30 meshes with a rack 36 fixedly mounted on an elongate backing member 37 which is in turn secured to a carriage 38 slidable along a vertical fixed pillar 39.The carriage comprises a pair of stiff abutment plates 40, 41 each carrying a bush 42 extending about the pillar, and a vertical post 43 to opposite ends of which the abutment plates 40 41 are secured by screws. The backing member 37 is fastened to the post 43 by screws 37a. A collar 45 is fixed between the two bushes 42 by a set-screw 46 enabling the position of the collar lengthwise of the pillar to be adjusted, and two compression springs 47, 48 are disposed about the pillar between the two bushes respectively and the collar. In this instance the springs 47, 48 are of equal strength and serve to bias the carriage 38 into a position in which the two abutment plates 40, 41 are equidistant from the collar. The two ends of the fixed pillar 39 are respectively fixed to top and bottom fixed stops 49, 50.

The carriage 38, toothed pulley 30 and rod 31 are shown in their upper limiting position in Figure 1 and in this position the vacuum cups 24 on the member 10 have engaged and are holding the bottom lid 11 in the stack. The pulley is at the upper end of the rack and abuts the abutment plate 40 which in turn abuts the top fixed stop 49. Downward movement of the pulley 30 is now actuated by the arm connected to rod 31. Initially the pulley does not move down the rack because the lower centering spring 48 is urging the whole carriage 38 downward away from the upper fixed stop 49, and the pulley 30 and its shaft 21, together with the member 10 in Figure 3 carry out a translatory downward movement without rotating.

When the carriage reaches a central position relative to the collar 45, the carriage stops and continued downward movement of the rod 31 causes the pulley to roll down the rack, rotating the shaft 21 and member 10. When the pulley reaches the lower end of the rack it comes into abutment with the bottom abutment plate 41, and continued downward movement of the rod 31 causes the pulley to push the carriage bodily downward, compressing the upper centering spring 47 between the collar 45 and the upper abutment plate 40, until the lower abutment plate 41 strikes the bottom fixed stop 50. In this last part of the movement, no rotation of the pulley, shaft 21 and member 10 occurs and the member carries out a downward translatory movement.The spacing of the abutment plates is such in relation to the toothed pulley and rack that the pulley is rotated through exactly 1800 by its movement along the rack. Thus, after its initial translatory downward movement the member's continued downward movement is first accompanied by a rotation of 1800 rotating the lid so that its foil side faces downward, and concludes as a simple translatory movement to place the ends of the bent lid in the recess in the container prior to release of the vacuum in the cups which release causes them to release the lid.

It will be understood that downward adjustment of the position of the collar 45 on the pillar 39 will lengthen the top and shorten the bottom translational non-rotational movement of the pulley, shaft 21 and member 10 and conversely.

In an alternative arrangement the rack 36 is in the form of an endless toothed belt extending about and clamped against post 43 by backing member 37. As the original length of the belt becomes worn, a fresh length of the belt can be brought into use by releasing the screws 37a, moving the belt about the backing member 37 and tightening the screws to clamp the belt in its new position.

WHAT WE CLAIM IS: 1. A mechanism for actuating in sequence a rotational and a translational drive movement of a member, which mechanism comprises a rack mounted for guided movement lengthwise of itself, a gear element in mesh with the rack and rotatably mounted on a support, a driven member connected to the gear element for rotational and translational movement therewith, means for moving the support of the gear element lengthwise of the rack, a first abutment for limiting movement of the gear element relative to the rack in one direction along the rack, a second abutment for limiting

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. communication with a vacuum source by way of a connection 24a, so that the bottom lid becomes attached to the cups. The member is then first drawn straight downward, and then rotated through 1800, and is then moved straight down again to its second position close to the container. The vacuum in the cups is then automatically released by the valve, so that the lid is released in the recess. The pivotal movement of the portions 22a which has occurred during the downward movement bends the lid resiliently into the form shown. In effect the lid is shortened by this bending and this facilitates placing the lid in its recess on the container and enables the lid to be placed even when, as is commonplace, the edge flanges of the container have become slightly damaged. Additionally the bending causes the rounded corners of the lid to form a lead-in for them into the rebate 13. Referring now to Figure 1, the mechanism is shown by which the upward and downward movements and 1800 rotations of the member 10 are actuated automatically. The shaft 21 on one end of which the support arm 20 is fixed has fixed on its other end a toothed pulley 30, and the shaft is carried in bearings on a rod 31 which constitutes the support for the pulley and which is guided for vertical sliding movement in a sleeve 32 mounted on a fixed part 33 of the mechanism. The lower end of rod 31 has an eye 35 for pivotal connection to a lifting and lowering arm (not shown). The toothed pulley 30 meshes with a rack 36 fixedly mounted on an elongate backing member 37 which is in turn secured to a carriage 38 slidable along a vertical fixed pillar 39.The carriage comprises a pair of stiff abutment plates 40, 41 each carrying a bush 42 extending about the pillar, and a vertical post 43 to opposite ends of which the abutment plates 40 41 are secured by screws. The backing member 37 is fastened to the post 43 by screws 37a. A collar 45 is fixed between the two bushes 42 by a set-screw 46 enabling the position of the collar lengthwise of the pillar to be adjusted, and two compression springs 47, 48 are disposed about the pillar between the two bushes respectively and the collar. In this instance the springs 47, 48 are of equal strength and serve to bias the carriage 38 into a position in which the two abutment plates 40, 41 are equidistant from the collar. The two ends of the fixed pillar 39 are respectively fixed to top and bottom fixed stops 49, 50. The carriage 38, toothed pulley 30 and rod 31 are shown in their upper limiting position in Figure 1 and in this position the vacuum cups 24 on the member 10 have engaged and are holding the bottom lid 11 in the stack. The pulley is at the upper end of the rack and abuts the abutment plate 40 which in turn abuts the top fixed stop 49. Downward movement of the pulley 30 is now actuated by the arm connected to rod 31. Initially the pulley does not move down the rack because the lower centering spring 48 is urging the whole carriage 38 downward away from the upper fixed stop 49, and the pulley 30 and its shaft 21, together with the member 10 in Figure 3 carry out a translatory downward movement without rotating. When the carriage reaches a central position relative to the collar 45, the carriage stops and continued downward movement of the rod 31 causes the pulley to roll down the rack, rotating the shaft 21 and member 10. When the pulley reaches the lower end of the rack it comes into abutment with the bottom abutment plate 41, and continued downward movement of the rod 31 causes the pulley to push the carriage bodily downward, compressing the upper centering spring 47 between the collar 45 and the upper abutment plate 40, until the lower abutment plate 41 strikes the bottom fixed stop 50. In this last part of the movement, no rotation of the pulley, shaft 21 and member 10 occurs and the member carries out a downward translatory movement.The spacing of the abutment plates is such in relation to the toothed pulley and rack that the pulley is rotated through exactly 1800 by its movement along the rack. Thus, after its initial translatory downward movement the member's continued downward movement is first accompanied by a rotation of 1800 rotating the lid so that its foil side faces downward, and concludes as a simple translatory movement to place the ends of the bent lid in the recess in the container prior to release of the vacuum in the cups which release causes them to release the lid. It will be understood that downward adjustment of the position of the collar 45 on the pillar 39 will lengthen the top and shorten the bottom translational non-rotational movement of the pulley, shaft 21 and member 10 and conversely. In an alternative arrangement the rack 36 is in the form of an endless toothed belt extending about and clamped against post 43 by backing member 37. As the original length of the belt becomes worn, a fresh length of the belt can be brought into use by releasing the screws 37a, moving the belt about the backing member 37 and tightening the screws to clamp the belt in its new position. WHAT WE CLAIM IS:

1. A mechanism for actuating in sequence a rotational and a translational drive movement of a member, which mechanism comprises a rack mounted for guided movement lengthwise of itself, a gear element in mesh with the rack and rotatably mounted on a support, a driven member connected to the gear element for rotational and translational movement therewith, means for moving the support of the gear element lengthwise of the rack, a first abutment for limiting movement of the gear element relative to the rack in one direction along the rack, a second abutment for limiting

said guided movement of the rack in said one direction, and means biasing the rack into a predetermined position spaced from the second abutment.

2. A mechanism as claimed in claim 1, further comprising a third abutment for limiting movement of the gear element relative to the rack in the opposite direction to said one direction, a fourth abutment for limiting said guided movement of the rack in said opposite direction, and means biasing the rack into said predetermined position away from said fourth abutment, said predetermined position of the rack being between the second and fourth abutments.

3. A mechanism as claimed in claim 2, wherein the rack is a straight rack and is secured to a carrier which is guided for rectilinear movement parallel to the lengthwise dimensions of the rack.

4. A mechanism as claimed in claim 3, wherein the carrier comprises a pillar to which the rack is secured and along which the rack extends, and two abutment members respectively secured to opposite ends of the pillar and projecting at right angles to the rack for abutment with the gear element.

5. A mechanism as claimed in claim 4, wherein a fixed rectilinear guide extends through guide apertures in the abutment members such that the abutment members can slide along the guide, said second and fourth abutments being secured to the rectilinear guide at locations spaced from each other along the guide.

6. A mechanism as claimed in any one of claims 3 to 5, wherein said rack is constituted by a run of an endless belt which is releasably mounted on the carrier for enabling a fresh length of the belt to be brought into operation to constitute said run.

7. A mechanism as claimed in any one of claims 1 to 6, wherein the driven member comprises a frame having suction cups mounted thereon and the length of the rack traversed by the gear element between the first and third abutments is selected so as to rotate the frame through 1800.

8. A mechanism for actuating in sequence a rotational and a translational movement of a member, which member is substantially as hereinbefore described with reference to and as illustrated in Figure 1 of the accompanying drawings.