WO2003078285A1

WO2003078285A1 - A gripping device for bottles and similar

Info

Publication number: WO2003078285A1
Application number: PCT/EP2003/002779
Authority: WO
Inventors: Matteo Zoppas; Andrea Saran; Alberto Armellin
Original assignee: S.I.P.A. Societa' Industrializzazione Progettazione E Automazione S.P.A.
Priority date: 2002-03-18
Filing date: 2003-03-18
Publication date: 2003-09-25
Also published as: ITRM20020147A1; ITRM20020147A0; AU2003223966A1

Abstract

A gripping device for containers (50), such as bottles or similar, suitable to be used on machines conveying containers for processing. This device comprises two levers (3, 4) ending in jaws (32, 32’) and including a toothed arc each; when reciprocally engaged, the two toothed-wheel arcs from a gear that imposes on each lever a mirror rotary movement of the other, causing the jaws (32, 32’) to open and close. The assembly of the device and the construction of the parts are simple and economical.

Description

A GRIPPING DEVICE FOR BOTTLES AND SIMILAR Technical field

This invention relates to a gripping device for containers such as bottles and similar. More particularly, it relates to a jaw-type gripping device for holding bottles, more particularly plastic bottles, by the neck; the device is suitable for use on a bottle, or similar, conveying plant for processing. Background art

During the production of plastic bottles, bottles normally undergo different operations (for example, blow moulding, painting, drying, and hardening of the paint with specific equipment), making it necessary to transport the bottles with different types of conveyors such as, for example, chain conveyors. These chain conveyors comprise several supports, the so-called chucks; substantially, these resemble pins and can be put inside the opening of the bottles, or grip the bottle around the neck or threading. A type of chuck has means for holding the bottle from the inside, such as moving parts that expand inside the bottle in the neck area or just below it, or, more simply, elastic parts (for example, a rubber ring) with an external diameter such that the bottle can be inserted in and removed from the support by force. Other types of chucks include means for gripping the neck or the end of the bottle from the outside. In order to load and unload the bottles onto/from the chucks, specific moving machinery is required, which generally includes several gripping devices able to engage a suitable outer part of the bottles. Sometimes, due to process requirements, the area available for gripping is limited to the threaded area at the end of the neck of the bottle or to the area just beneath: for example, when the body of the bottles is covered with fresh paint. The gripping devices are a part of moving mechanisms synchronized with chain or belt conveyors, with star wheels, etc.

Known gripping devices open and close upon receiving a command from suitable mechanisms operated at the right time. For example, they can include levers, or similar items, that open the jaw if operated by appropriate components belonging to the conveying machine. These mechanisms can include cams appropriately connected. Sometimes, in the production process of bottles, or more in general of containers, there is the problem of transferring the bottles directly from one gripping device to another: for example, when unloading from a conveyor of the type discussed above -to loading onto another of type of conveyor. These transfers are sometimes accomplished through an exchange wheel or a group of wheels that feature a set of gripping elements that remove the bottles from the grippers of the unloading mechanism and hand them over to a loading mechanism placed after the former, which grips the bottles again. Some of the gripping devices include specific mechanisms that command opening every time it is necessary, and, furthermore, must ensure the solidity and precision of the grip, which becomes crucial during high-speed transfers typical of high output plants.

Gripping devices are generally found in large numbers on a bottle-processing plant, and must be very reliable even at high conveying speeds. Toggle-action grippers are known for opening and closing the included jaws.

Document EP 854 102 shows a gripping device for bottles with two pivoted jaws on a single element; the jaws are closed through the action of a compressed spring. The action of the spring is transmitted through two connecting rods, each pivoted on the end of one of the jaws, opposite to the bottle-gripping area. A lever, integral with one of the connecting rods, determines the opening of the jaws when it is pushed by a cam. The opening and closing mechanism of the jaws described in the document in question, makes the gripper rather bulky. Furthermore, making and assembling the device is quite complex. For applications where the devices move at high speeds, another drawback is that the maximum possible aperture of the jaws may be inadequate without getting into each other's way. This is the case, when loading and unloading the bottles onto conveyors, or when transferring bottles between two gripping devices. Currently, this aperture problem can only be resolved by increasing further the size of some of the mechanical parts, making the device even more bulky. Given the large number of gripping devices found in general on a bottle- processing plant, it is highly desirable to have a gripping device that is both simple to manufacture and assemble, has a good maximum aperture of the jaws without this involving size problems of some of the parts, and can be used also with larger bottle necks or larger containers. Objects of the invention

One object of the invention is to provide a gripping device that overcomes the problems set forth above, in particular making an easy-to-make and easy-to- assemble device that is reliable during operation, and guarantees great bottle or container-gripping security and stability.

These objects, as well as others that will be better explained below, are achieved by means of a gripping device for bottles and similar containers comprising two levers positioned basically on the same plane. Each lever is able to rotate around its respective hinge fastened to a supporting element of said device and is integral with a respective toothed-wheel arc. Said two levers are able to open and close the gripping device by engaging the gear formed by said toothed-wheel arcs. Thanks to these characteristics, the gripping device for bottles has a simplified structure comprising two levers able to rotate on a same plane; furthermore, each lever is integral with a toothed-wheel arc that engages with the toothed-wheel arc of the other lever to form a moving gear. The two levers are preferably hinged to a same element, and the toothed-wheel arcs are preferably machined on the body of the levers. The gear enables the jaws to rotate in a mirrored manner to the other, and the centre of the toothed-wheel arc is on the axis of rotation of the lever; this makes it possible to obtain a symmetric movement.

Preferably, each lever has a jaw at an end, and the jaw device formed by both levers grips the bottle or similar container. The jaws can have some appropriate inserts, preferably interchangeable, in order to adapt to the different sizes of the different types of containers or to the different parts of the container to be gripped. In accordance with another aspect of the invention, a mechanism is included for closing or opening the jaws, where closing means bringing the jaws of the two levers closer together and opening means the opposite movement. In accordance with another preferred aspect of the invention, elastic means can be included, preferably capable of acting directly on both levers, to close the jaws; to open the jaws, the elastic means can act on at least one of said levers, overcoming the resistance of said elastic means. Said elastic means can be a spring, preferably generally compressed.

In accordance with a particular aspect of the invention, said elastic means are connected to.the ends of said levers, opposite to the. ends having the jaws. In accordance with a further aspect of the invention, said elastic means are a spring, placed with its axis perpendicular to the plane of symmetry of the rotary movements of the two levers. Brief description of the drawings Figure 1 shows a schematic, axonometric view of a device in accordance with this invention, with the jaws closed gripping a bottle.

Figure 2 shows a schematic view from above of a device in accordance with this invention, with the jaws closed gripping a bottle.

Figure 3 shows a schematic, expanded view of a device in accordance with this invention. Description of an embodiment of the invention

Figure 1 shows a view of a jaw-type gripping device in accordance with this invention in the gripping position. The jaws 32, 32' are closed gripping the neck of a bottle 50. The levers 3 and 4 are visible and are free to rotate around the axes 37, 37' of the screws 31 and 31'. The gear formed by the two toothed-wheel arcs 36, 36^* is hidden from view by the plate 33. By turning the arm 34, which is integral with the lever 4, the lever 4 turns around the axis 37; consequently, also the lever 3 turns, since it is tied kinetically to the lever 4 through said gear. This causes the opening of the jaws 32 and 32', and the compression of the spring 11. Once the action on said arm 34 ceases, the spring 11 will close said jaws. According to a possible use of a device in accordance with this invention, the arm 34 can be operated by a cam belonging to the system in which the device is used; it can also be operated by another equivalent command system not shown in the figures. With reference to Figure 1 , the roll 5 is fastened to said arm 34 as shown in the figure. This can serve as a body assigned to follow the contour of the cam, or to interact functionally with another similar body having the function of causing the device to open, meaning the opening of the jaws. The insets 8 and 15 fastened to the jaws serve to adapt the device to the bottle 50 to be gripped, preferably in the area of the neck, and to guarantee the stability during movements caused by knocks or by inertia during the operations. In this way, it is possible to do away with other supporting or gripping elements in other areas of the body of the bottle, which could cause damage or defects if the bottle still has paint that has not yet reticulated or dried.

According to process requirements, there can also be an insert 14 fitted on the plate 1 , in order to improve the positioning and the fastening of the bottle during gripping. Figure 2, where the plate 33 has been omitted to display the mechanism better, shows the two-toothed arcs 36 and 36' that are preferably, but not necessarily, machined directly on the levers 3 and 4 and engage reciprocally to form a gear. The pins 37 and 37' form the pivots of the levers 3 and 4. It is also possible to see how the spring 11 is positioned: it is arranged in a compressed position between the ends of the levers 3 and 4 opposite to the ones of the jaws and is held in place by teeth or pins 38 and 38', machined on said ends of the levers. An action on the arm 34 in the direction of the arrow A causes the clockwise rotation of the lever 4 and the counterclockwise rotation of the lever 3. The action of the spring 11 resists elastically to the movement and causes the inverse movement when the pressure on the arm 34 ceases. If necessary, there can be limit stops to block the closure of the jaws in a specific position. For example, the two limit stop pins 9 and 9' prevent the levers 3 and 4 to rotate further and close the jaws as shown in figure 2. Figure 3 shows the expanded view of the device in accordance with this invention where the already described parts are shown, among other things. In particular, note the configuration of the levers 3 and 4. It is also possible to see how the toothed section 36' is directly machined on the lever 3, forming one piece. This solution simplifies the production process of the levers 3 and 4 and of the respective gear. The levers 3 and 4 have holes 40 and 40' through which the pins 41 and 41' pass. Said pins are integral with or fixed to the plate 1. These pins 41 , 41' have a threaded hole for the screws 31 and 31' that fasten the plate 33 that, in turn, holds the levers 3 and 4 in position. If necessary, there can be bushes 6 and 6', preferably self-lubricating, made of appropriate antifriction material in order to reduce the friction between the reciprocally moving parts. The pins 9 and 9' are held in place at the ends, in the corresponding holes found in the plates 1 and 33. Also note the spacer plate 2 that can be interposed between the plate 1 and the levers 3 and 4 in order to position them correctly; if present, this can be preferably made of antifriction material.

The inserts 8, 14, 15 to be fastened to the jaws 32' and 32 of the levers 3 and 4 and to the plate 1 can also be seen. In this case, the inserts are arranged so that they can grip the bottles from the neck, gripping the threaded part and the immediate area included between the threaded part and the ring if present. The "ring" is a ring-like projecting part, essentially in the shape of a flange, that is usually found around the neck of many types of plastic bottles. The inserts can be changed to adapt the gripping device to different types of bottles or to different gripping points. This makes it possible to use a same model of gripper on different systems, or in different parts of the same system. In fact, it may be necessary to change the gripping point: for example, it may be necessary to transfer the bottle directly from a jaw-type gripping device to another. In this case, one of the gripping devices can grip the bottle in the threading area, leaving free the area included between the threading and the ring, which is gripped by the other gripping device. The inserts are made of an appropriate material for example, polymeric material or metal, which is able to dampen vibrations and features an appropriate friction coefficient.

The dimensions of the inserts are equal to the height of the threaded area if the bottle is gripped there, or equal to the height of the area found between the seal breaker and the ring, or even equal to the height of the cylindrical area immediately under the ring.

In accordance with a possible alternative of the invention, the jaws can be structured with the dimensions necessary to adapt to the gripping point without the need to apply inserts. The person skilled in the art can easily select the materials for making the different parts of the device. For example, the levers and the different plates can be made of stainless steel, while the other parts, such as the bushes and the inserts, can be made of polymeric material. The choice should consider the particular operating conditions, especially if the device is used to convey the container through particular processing phases involving chemical and physical treatments to the bottles. From the description and from the figures, it is apparent that the parts that make up the device in accordance with this invention can be obtained through simple machining. For example, the levers comprising the toothed arcs can be obtained through laser cutting, which enables economical and precise machining. This is also true for the other metal parts, differently from what occurs for devices including toggle-action mechanisms, such as those of the known technology.

Another advantage is the possibility of obtaining a large maximum aperture of the jaws, without complicating or bulking up the mechanism. The aperture achieved during a cycle can easily be adjusted through the rotation of the lever on which the specific bodies of the machinery act; for example, this can be carried out by appropriately choosing the section of a cam. The available large maximum aperture confers, thus, great versatility to the device.

Furthermore, in accordance with this invention, it is possible to remove a container gripped by a device simply by pulling it away from the jaws, without having to act on the opening mechanism. Normally, this is not possible with devices having a toggle-action mechanism, such as the ones of the background art; in fact, if this is attempted, the container breaks. Being able to remove the containers is desirable, since it makes it possible to eliminate any badly positioned containers, possibly with appropriate position determining and extraction mechanisms, avoiding problems in the following processing steps. The described device can be fastened, preferably using the plate 1 , with appropriate means such as screws, to specific bodies of a bottle-conveying plants, such as a wheel equipped with a series of devices of this kind along the circumference or moving plates or trolleys. As we have seen, the device in accordance with this invention is suitable for moving bottles, or even parisons, but can also be used for other types of containers, after making appropriate changes.

Claims

1. A jaw-type gripping device for bottles, or similar containers, comprising two levers (3, 4) arranged substantially on the same plane and adapted to rotate around respective hinges (37, 37'), which are fastened to a supporting element

(1) of said device, each of said levers (3, 4) being integral with a respective toothed-wheel arc (36', 36), and wherein said two levers are suitable to open and close the gripping device by reciprocally engaging the gear formed by said toothed-wheel arcs.

2. A device as claimed in claim 1 wherein said levers (3, 4) are provided with respective jaws (32, 32') fixed at one end for gripping the bottles.

3. A device as claimed in one of the previous claims wherein said toothed-wheel arcs (36, 36') are machined on the body of the levers (3, 4).

4. A device as claimed in one of the previous claims wherein said levers (3, 4) can rotate specularly to each other on the same plane.

5. A device as claimed in claim 3 or 4 wherein elastic means (11 ) act on said two levers (3, 4) to close the jaws (32, 32').

6. A device as claimed in claim 5 wherein said elastic means consist of a spring (11).

7. A device as claimed in claim 6 wherein at least one of said levers (4) is integral with a specific command body, suitable to make the jaws (32, 32') open and/or close.

8. A device as claimed in one of the previous claims where the inserts (8, 14, 15) fastened to said jaws (32, 32') and to the plate (1) have a thickness essentially equal to the gripping area on said bottles.