GB2318779A

GB2318779A - Gripping device

Info

Publication number: GB2318779A
Application number: GB9622825A
Authority: GB
Inventors: David William Heap; Robert Porter
Original assignee: BWI DAWSON
Current assignee: BWI DAWSON
Priority date: 1996-11-01
Filing date: 1996-11-01
Publication date: 1998-05-06
Anticipated expiration: 2016-11-01
Also published as: GB9622825D0; GB2318779B

Abstract

The invention relates to a device (10) for gripping an object such as a bottle, and also to a bottle-handling machine (40, Fig.4) incorporating the device. The device includes a body portion (13) which is for mounting in a bottle-handling machine and has extending therefrom first (22) and second (23) arms for gripping the object. The first and second arms are rotatable about respective first and second axes, and have respective first (20) and second (21) cooperating surfaces. One of the first and second arms also has a first cam follower (25). Contact of the first cam follower (25) with a cam causes its respective arm to rotate about its axis of rotation. The first and second cooperating surfaces cause the rotation of that arm to be transmitted to the other arm, thereby to rotate the first and second arms towards or away from each other to grip or release an object.

Description

GRIPPING DEVICE This invention relates to a gripping device.

The device of the invention may be used in a bottle-handling machine to grip a bottle so that the bottle can be manoeuvred to allow certain operations to be performed on the bottle, and is described hereinafter with reference to this use. However, the device of invention is not limited to this use and can be used to grip any object.

In the prior art, bottle gripping devices typically have a pair of generally arcuate arms which are movable relative to each other so that they can grip a bottle therebetween. In some conventional bottle gripping devices, one of the arms is fixed and the other of the arms is arranged to move relative thereto. However, bottle gripping devices of this type have problems with the feed and discharge of bottles.

In particular, devices of this type cannot be used to grip bottles having a large diameter neck because the trailing fixed arm thereof interferes with the bottle neck at the feed and discharge points of a bottlehandling machine.

Accordingly, bottle gripping devices have been developed in which both arms move to grip and release the battles. Although these bottle gripping devices generally overcome the above-mentioned problem, they require many complicated moving parts involving springs and levers, and consequently are expensive and prone to mechanical failure.

According to a first aspect of the present invention, there is provided a device for gripping an object, comprising: a body portion for mounting in a machine for handling said objects, and having extending therefrom first and second arms for gripping the object, the first and second arms being rotatable about respective first and second axes, and having respective first and second cooperating surfaces, one of the first and second arms also having a first cam follower, the arrangement being such that contact of the first cam follower with a cam causes said one of the first and second arms to rotate about its axis of rotation, the first and second cooperating surfaces causing the rotation of said one of the first and second arms to be transmitted to the other of said one of the first and second arms, thereby to rotate the first and second arms towards or away from each another to grip or release an object.

The device of the present invention is of a simple construction with few moving parts and, accordingly, is reliable and can be produced more cheaply than conventional bottle gripping devices in which both arms of the bottle gripping device move to grip a bottle.

The first and second cooperating surfaces may be any which cause the rotation of one of the first and second arms to be transmitted to the other of the first and second arms, e.g. gear tooth profiles. However, it is currently preferred if the first and second cooperating surfaces are a male cam portion and a corresponding female cam portion1 because such portions are strong and easy to manufacture.

In a preferred embodiment, the-body portion is for being rotatably mounted in a machine for handling said objects and has mounted thereon a second cam follower, the arrangement being such that contact of the second cam follower with a cam causes the body portion to be rotated through a predetermined angle. The predetermined angle may be 1800 such that an object carried by the device is inverted. The device of this embodiment may typically, but not exclusively, be used in a bottle-cleaning machine in which bottles are gripped and inverted so that a cleaning liquid can be sprayed into the bottle from below. Cleaning may also be carried out by blowing sterile air into the bottles or by applying a vacuum thereto.

Preferably, each of the arms of the device has a spindle extending therefrom into the body, the spindles including the first and second cooperating surfaces.

With this arrangement, the cooperating surfaces are located within the body, which means that the device has a compact configuration with a minimum of exposed moving parts, and that the cooperating surfaces can be surrounded with a lubricant, e.g. grease, within the body.

The first and second arms may be resiliently biased towards each other by spring means, contact of the first cam follower with a cam causing the first and second arms to rotate away from each another so that an object can be received therebetween. Although the spring means can be any type of spring arrangement, e.g. a leaf spring, etc, it is preferred if it is a spring located around the body portion. In this embodiment, the arms are biased together, i.e. into the closed position, and are opened by contact of the first cam follower with a cam so that an object can be received between the arms and gripped when the first cam follower no longer contacts the cam.

Furthermore, the first and second arms may extend from the lower end of the body, the spring being located between the upper of the arms and a collar around the body portion. Alternatively, the first and second arms may extend from the upper end of the body, the spring being located between the lower of the arms and a collar around the body portion. The position of the collar on the body portion may be adjustable so as to adjust the torsion applied by the spring to the upper (or lower) of the arms. This allows the device to grip objects of varying sizes and weights.

According to a second aspect of the present invention, there is provided a machine for handling objects including a device in accordance with the first aspect of the present invention. Such a machine may be any type of machine in which it is required that objects be gripped in order that certain operations can be carried out on the objects. It is preferred that the device in accordance with the first aspect of the invention includes the second cam follower in order that it can invert the object that it is gripping.

When the object to be gripped is a bottle, inversion of the bottle allows various operations to be carried out on the bottle, e.g. emptying of the contents thereof, drying by spraying hot air from below, etc. It is currently most preferred that the device be used in a bottle-cleaning device in which cleaning fluid or the like is sprayed into the bottles from below when they are inverted.

According to a third aspect of the present invention, there is provided a machine for handling objects, comprising: at least one device in accordance with the first aspect of the present invention, arranged to travel around a continuous drive path; a first location at which objects are presented to the drive path, a first cam means being located adjacent the drive path at the first location and arranged to contact the first cam follower of the device as the device passes the first location, such that the arms of the device are rotated away from each other to receive therebetween an object presented at the first location and are then rotated towards each other to grip the object; and a second location at which objects are discharged from the drive path, a second cam means being located adjacent the drive path at the second location and arranged to contact the first cam follower of the device as the device passes the second location, such that the arms of the device are rotated away from each other to release an object gripped therebetween.

Preferably, the machine further comprises a third cam means located adjacent the drive path at the first location and arranged to contact the second cam follower of the device as the device leaves the first location and invert the device and the object gripped by the device, and a fourth cam means located adjacent the drive path at the second location and arranged to contact the second cam follower of the device as the device arrives at the second location and invert the device and the object gripped by the device.

The drive path may be generally circular, the first and second cam means being formed by a single first cam, and the third and fourth cam means being formed by a single second cam, the arrangement being such that, as a device approaches the second location, the second cam inverts a device and an object gripped by the device and the first cam causes the device to release the object at the second location, the device then contacting another object at the first location and the first cam causing the device to grip said another object and then the second cam inverting the device and said another object as the device leaves the first location. In this aspect of the invention, the machine is preferably a bottle-handling machine.

Preferably, the machine further comprises bottlecleaning means arranged between the first and second locations.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which: Figure 1 is a side view of a gripping device in accordance with the present invention; Figure 2 is a sectional view along the line A-A in Figure 1; Figure 3 is a sectional view along the line B-B in Figure 2; Figure 4 is a partial and simplified side view of a rotary bottle cleaning machine incorporating the gripping device of Figure 1; and Figure 5 is a plan view of the rotary bottle cleaning machine of Figure 4.

Referring to Figure 1, a gripping device 10 in accordance with the invention comprises a pivot bar 11 which is for rotatably mounting on a pivot shaft 12. A gripper post 13 is grub-screwed and welded into pivot bar 11 at one end and, at the other end, is received within a sleeve 14. Gripper post 13 and sleeve 14 are secured together by means of a pin 15 which extends therethrough.

Referring to Figure 2, a bush 16 of, for example, Nylatron (Trademark) material (although any suitable material could be used) is located within sleeve 14 and is secured against rotation by a pair of opposed recesses in the periphery thereof engaging a corresponding pair of downwardly-extending tangs 17 of sleeve 14 (see Figure 1). Two grub screws (not shown) extend through sleeve 14 into bush 16 further to secure bush 16 therein. Bush 16 has two bores therein which receive spindles 18, 19, respectively, and is formed in two parts so as to fit around spindles 18, 19.

The upper ends of spindles 18, 19 extend beyond bush 16 in sleeve 14 and, at this point, spindle 18 has a larger diameter head portion which includes a male cam portion or projection 20 which is received in a female cam portion or recess 21 in a corresponding larger diameter head portion of spindle 19 (see Figure 3). Engagement of the respective cam portions 20, 21 means that rotation of spindle 18 by a predetermined angle in one direction causes spindle 19 to rotate by the same angle in the opposite direction.

The lower end of spindle 18 is connected to an upper arm 22 and the lower end of spindle 19 passes through an elongate aperture 22a in upper arm 22 and is connected to a lower arm 23. Aperture 22a is elongate to allow rotation of the lower arm 23 relative to the upper arm 22.

Upper arm 22 and lower arm 23 are both generally arcuate in configuration so that they define between them an area in which a bottle is received (see Figure 3). Secured to the respective upper surfaces of arms 22, 23 by means of screws is an arcuate tapered section 23a. These sections are for having secured thereto an insert of a resilient material shaped to grip snugly the neck of a bottle. The resilient inserts increase the friction between the arms 22, 23 and the bottle, and thereby improve the grip therebetween. Upper arm 22 also includes an extended portion 22b from which a post 24 extends upwardly. A first cam follower roller 25 is rotatably mounted on post 24.

A torsion spring 26 is located around sleeve 14 between upper arm 22 and a retainer collar 27. One end of torsion spring 26 is received in a bore in upper arm 22 and the other end is received in-a bore in retainer collar 27 so that upper arm 22 is biased inwardly towards lower arm 23, i.e. into the closed position.

Retainer collar 27 is releasably secured to sleeve 14 by means of a grub screw 28 (see Figure 2) so that it can be moved around sleeve 14, thereby to increase or decrease the torsion that spring 26 applies to upper arm 22. This adjustment allows bottles of varying sizes and weights to be gripped by the bottle gripping device 10.

Referring again to Figure 1, pivot bar 11 also has secured thereto one end of a roller post 29, the other end thereof having a second cam follower roller 30 rotatably mounted thereon. It can be seen from Figure 1 that roller post extends downwardly and away from pivot bar 11.

Gripping device 10 functions to grip an object in the following manner. In use, a gripping device 10 is attached to a suitable support and is driven around a drive path - which is typically continuous - relative to an object-transporting path. immediately before the point at which objects are to be picked up by the gripping device, the drive path includes a first cam which is arranged to engage the first cam follower roller 25 of a gripping device 10 as it passes.

Referring to Figure 3, the first cam causes first cam follower roller 25 to move in the direction of the arrow A, thereby causing the spindle 18 to rotate in the clockwise direction and move upper arm 22 in the direction of the arrow B. The rotation of spindle 18 is simultaneously transmitted to spindle 19 by means of the male cam portion 20 and female cam portion 21 so that spindle 19 rotates in the anticlockwise direction and moves the lower arm 23 in the direction of arrow C.

Thus, the arms 22, 23 are moved apart, typically by about 100, so that an object can be received therebetween.

As the gripping device 10 continues around the drive path, the first cam is shaped such that first cam follower roller 25 disengages the cam so that the arms 22, 23 are moved together under the action of torsion spring 26, thereby to grip the object.

At the point at which the objects are to be released by the gripping device 10, a second cam of the drive path engages the first cam follower roller 25, causing it to move in the direction of arrow A. This has the effect that the arms 22, 23 are moved apart in the manner described above and the object is released by the gripping device 10.

Turning now to Figures 4 and 5, one example of the use of the gripping device 10 will be described with reference to a rotary bottle-cleaning machine 40. In this case, a bottle 41 is passed along a first conveyor 42 to a first, infeed star wheel 43 from where it is picked up by a gripping device 10 and passed around a generally circular drive path before being released onto a second, discharge star wheel 44 and thence onto a second conveyor 45. Whilst on the circular drive path, the bottle is inverted through 1800 and a cleaning operation takes place (for example, by spraying detergent or disinfectant into the upturned bottle).

In more detail, first conveyor 42 extends into machine 40 from another bottle-handling apparatus. As bottles 41 approach the end thereof, a feed worm or scroll 42a spaces the bottles 41 so that they match the spacing of rotating infeed star wheel 43. Bottles 41 enter the pockets of infeed star wheel 43 and are moved from the first conveyor 42 to below the outer periphery of a disc 46 having a vertical axis of rotation. At the periphery of disc 46, each of a plurality of gripping devices 10 is rotatably mounted on a pivot shaft 12 extending between a pair of brackets 47.

As disc 46 rotates, gripping devices 10 are moved around a generally circular drive path in the direction of arrow D in Figure 5. However, between the centre line of the discharge star wheel 44 and the centre line of the infeed star wheel 43 (about 40 of the circle), gripping devices 10 are moved out of the circular path by a cam 48. This cam 48 contacts the first cam follower roller 25 of a gripping device as it passes the centre line of discharge star wheel 44 and causes the arms 22, 23 of the gripping device to be moved apart in the above-described manner so that the neck of a bottle 41 carried by the device 10 is released into one of the pockets of rotating discharge star wheel 44.

Cam 48 ensures that the device 10 remains in the "open" configuration until it passes the centre line of the infeed star wheel 43. Here, the neck of a bottle carried by the infeed star wheel 43 is received between the arms 22, 23 of the device. However, as the device 10 continues along the drive path, first cam follower roller 25 no longer contacts cam 48 and the arms 22, 23 close around the neck of the bottle 41.

Throughout the travel around the drive path, second cam follower roller 30 is received between a second cam comprising two round bars (not shown) which straddle the roller 30. These bars twist in such a manner that the gripping device 10 is caused to rotate 1800 about pivot shaft 12 so that the bottle 41 is inverted as it leaves infeed star wheel 43 and travels further around the drive path.

When the gripping device 10 and bottle 41 approach the discharge star wheel 44, the bars of the second cam twist again in such a manner that the gripping device 10 rotates back through 1800 so that the bottle 41 is no longer inverted. In addition, as mentioned above, first cam follower roller 25 contacts the cam 48, opening arms 22, 23 and releasing bottle 41 onto discharge star wheel 44. Discharge-star wheel 44 rotates to move the bottle 41 onto second conveyor 45 for conveying onto a further process, e.g. filling.

Claims

CLAIMS:

1. A device for gripping an object, comprising: a body portion for mounting in a machine for handling said objects and having extending therefrom first and second arms for gripping the object, the first and second arms being rotatable about respective first and second axes, and having respective first and second cooperating surfaces, one of the first and second arms also having a first cam follower, the arrangement being such that contact of the first cam follower with a cam causes said one of the first and second arms to rotate about its axis of rotation, the first and second cooperating surfaces causing the rotation of said one of the first and second arms to be transmitted to the other of said one of the first and second arms, thereby to rotate the first and second arms towards or away from each another to grip or release an object.

2. A device as claimed in claim 1, wherein the first and second cooperating surfaces are a male cam portion and a female cam portion.

3. A device as claimed in claim 1, wherein the first and second cooperating surfaces are gear tooth profiles.

4. A device as claimed in claim 1, 2 or 3, wherein the body portion is for being rotatably mounted in a machine for handling said objects and has mounted thereon a second cam follower, the arrangement being such that contact of the second cam follower with a cam causes the body portion to be rotated through a predetermined angle.

5. A device as claimed in claim 4, wherein the predetermined angle is 1800 such that an object carried by the device is inverted.

6. A device as claimed in any preceding claim, wherein each of the arms has a spindle extending therefrom into the body, the spindles including the first and second cooperating surfaces.

7. A device as claimed in any preceding claim, wherein the first and second arms are resiliently biased towards each other by spring means, contact of the first cam follower with a cam causing the first and second arms to rotate away from each another so that an object can be received or released from between the arms.

8. A device as claimed in claim 7, wherein the spring means is a spring located around the body.

9. A device as claimed in claim 8, wherein the first and second arms extend from the lower end of the body, the spring being located between the upper of the arms and a collar around the body.

10. A device as claimed in claim 9, wherein the position of the collar on the body portion is adjustable so as to adjust the torsion applied by the spring to the upper of the arms.

11. A device as claimed in any preceding claim, wherein the first and second arms are arranged to carry a resilient material for gripping the object.

12. A device for gripping an object substantially as hereinbefore described with reference to and as shown in Figures 1 to 3 of the accompanying drawings.

13. A device as claimed in any preceding claim, wherein the object is a bottle.

14. A machine for handling objects including a device as claimed in any preceding claim.

14. A machine for handling objects, comprising: at least one device as claimed in any one of claims 1 to 13, arranged to travel around a continuous drive path; a first location at which objects are presented to the drive path, a first cam means being located adjacent the drive path at the first location and arranged to contact the first cam follower of the device as the device passes the first location, such that the arms of the device are rotated away from each other to receive therebetween an object presented at the first location and are then rotated towards each other to grip the object; and a second location at which objects are discharged from the drive path, a second cam means being located adjacent the drive path at the second location and arranged to contact the first cam follower of the device as the device passes the second location, such that the arms of the device are rotated away from each other to release an object gripped therebetween.

16. A machine as claimed in claim 15, further comprising a third cam means located adjacent the drive path at the first location and arranged to contact the second cam follower of the device as the device leaves the first location and invert the device and the object gripped by the device, and a fourth cam means located adjacent the drive path at the second location and arranged to contact the second cam follower of the device as the device arrives at the second location and invert the device and the object gripped by the device.

17. A machine as claimed in claim 16, wherein the drive path is generally circular, the first and second cam means being formed by a single first cam, and the third and fourth cam means being formed by a single second cam, the arrangement being such that, as a device approaches the second location, the second cam inverts a device and an object gripped by the device and the first cam causes the device to release the object at the second location, the device then contacting another object at the first location and the first cam causing the device to grip said another object and then the second cam inverting the device and said another object as the device leaves the first location.

18. A machine as claimed in claim 15, 16 or 17, further comprising bottle-cleaning means arranged between the first and second locations.

19. A bottle-handling machine substantially as hereinbefore described with reference to and as shown in Figures 4 and 5 of the accompanying drawings.