IE84392B1 - An excavator tool quick attachment device - Google Patents

Abstract

ABSTRACT An excavator tool quick attachment device (10) comprises a body with a hook (12,14) at or about each end for engagement with one of a pair of connecting pins disposed on a tool. The first hook (12) is of open construction and the second hook (14) has a spring loaded locking means (30) movable to lock against the pin engaged in the second hook. The locking means (30) is spring loaded into the locked position. A retainer (34) is biased into a position to maintain the locking means (30) in the open position. A release element (42) at one end of the retainer is adapted to be activated by the pin on the required tool engaging in the second hook (14). Accordingly when the pin comes in contact with the release element (42), the retainer (34) is moved into a release position and the locking means (30) moves into its locked position about the pin.

Description

AN EXCAVATOR TOOL QUICK ATTACHMENT DEVICE The present invention relates to an excavator tool quick attachment device and more particularly to a mechanically operated safety mechanism for an excavator tool quick attachment device.

Pneumatic/hydraulic latches on quick attachment devices are well known and are generally mounted on a tool engaging portion which has two hooks, one of which is on each end of the device. The excavator operator locates one of the hooks around the first pin of the tool and raises a dipper arm of the excavator. The rams of the dipper arm are manipulated until the second hook is located adjacent the second pin of the tool and a pneumatic/hydraulic latch comprising a hydraulic/pneumatic piston connected between the attachment device and the latch is actuated to lock the second pin of the tool onto the quick attachment device.

The problem with this latch is that failure of the hydraulic/pneumatic cylinder could result in the latch opening and allowing the tool such as a bucket to become separated from the quick attachment device with potentially disastrous consequences for anyone in the vicinity. A number of safety pins and other safety mechanisms have been developed but most of these require to be inserted manually. Further secondary safety systems utilising hydraulic systems have also been developed which add extra system maintenance and expense.

Also for smaller sized excavators or diggers, it is not feasible to provide a hydraulically operated device. Such excavators or diggers utilise mechanically operated attachment devices. Such a device must be manually opened and manually closed and a safety pin is required to be manually inserted into the device. These operations can be quite time consuming and the manual insertion of the safety pin causes a major safety problem as typically an operator will more often than not forget or neglect to re-insert the safety pin after the attachment of the device to the required tool such as a digging bucket.

It is an object of the present invention to overcome the need for manually operable safety pins or complex hydraulic systems, both of which are used to prevent unintended release of the tool from the quick attachment device.

An excavator tool quick attachment device of the type comprising a body with a hook at or about each end for engagement with one of a pair of connecting pins disposed on a tool, the first hook being of open construction and the second hook having a spring loaded locking means movable to lock against the pin engaged in the second hook, the locking means being spring loaded into the locked position, a retainer biased into a position to maintain the locking means in the open position, a release element at one end of the retainer adapted to be activated by the pin on the required tool engaging in the second hook, whereby when the pin comes in contact with the release element, the retainer is moved into a release position and the locking means moves into its locked position about the pin and in which a spring loaded safety means is provided which is operable to be maintained in the open position by the retainer when biased into the position to maintain the locking means in the open position, and is operable to be moved into the locked position on movement of the retainer into the position to maintain the locking means in the closed position, the safety means only being releasable from its locked position by the user pulling the safety means back into the open position against the force of its spring.

Preferably, the locking means is moveable back into the release position by a manually operable lever.

Conveniently, the lever includes a removable handle and a stub or bush on which the handle is removably mounted.

Ideally, the locking means includes an adjustable coil spring, so that the spring loading of the locking means can be adjusted over time to compensate for wear and the like.

Preferably, the coil spring is mounted about a central bar so as to help to prevent material from clogging the spring.

Advantageously, the first hook is provided with an extended lower lip to enhance the engagement with the said supporting pin disposed on the tool.

Preferably, the extended lower lip is provided with a curved end.

The invention will hereinafter be more particularly described with reference to the accompanying drawings which show, by way of example only, two embodiments of an excavator tool quick attachment device according to the invention. In the drawings: — Figure 1 is a cross-sectional side view of a first embodiment of the device in its normal fully locked mode; Figure 2 is a cross-sectional side view of the first embodiment of the device in a partially released mode; Figure 3 is a cross-sectional side view of the first embodiment of the device in its fully released and unlatched mode; and Figure 4 is a cross-sectional side view of a second embodiment of the device in its normal fully locked mode.

Referring to the drawings, the first embodiment of the excavator tool quick attachment device 10 comprises an open hook 12 directed rearwardly of the device and a closable hook 14 directed downwardly of the device. The hooks 12 and 14 are used to engage with pins 20 (only one of which is shown) of a tool, such as a bucket, to which the device is connected to. The device 10 is fixed to the dipper arm of an excavator (not shown) by means of retaining orifices 22 and 24.

The hook 14 is closed by a latching plate 30 which moves to engage about the pin 20.

The latching plate 30 is moved under the force of spring 32 which is a compression spring. As shown in Figure 3 the latching plate 30 is maintained in an open position by a retainer 34 seated in a pin 36 on the latching plate 30 which is kept engaged by tension spring 38. Safety pin 40 is kept in an open position by the retainer plate 34. The retainer plate 34 has a heel 42 at its end remote from its pivot position 35.

Referring now to Figure 2, it will be appreciated that on engagement of the device 10 with the desired tool, the heel 42 is brought into contact with the pin thus causing the retainer plate 34 to pivot about the pivot point 35 thereby lifting the retainer plate from engagement with the pin 36. On the release of the pin 36, the latching plate moves forward under force from the spring 32 and engages the pin 20. At the same time the safety pin 40 is released and moves under the force of its own spring (not shown) to behind the latching plate 30 thereby preventing the latching plate 30 from disengaging from the pin 20.

When it is desired to release the latching plate 30, the safety pin 40 must first be pulled laterally so that the latching plate 30 can then be moved back by means of the manually operated lever 50 against the force of the spring 32 until the retaining plate 34 engages with the pin 36. The lever 50 comprises a removable handle 51 and a stub 52 formed on the latching plate 30. The pressure in spring 32 can be maintained by periodically adjusting lock nuts 60 so as to compensate for wear. The spring 32 is provided around a central adjustment bar 62. This arrangement helps to prevent build up of material such as clay and the like from building up within the coils of the spring and which otherwise could interfere with the proper functioning of the spring 32.

The excavation tool quick attachment device of the invention provides a safe and easily operated means of speedily changing tools and implements on an excavator. Even if the hook 12 becomes disengaged from its pin, the hook 14 provides a positive lock on the pin.

Also, the safety pin 40 is always engaged in use and can only be released by pulling it out while at the same time pulling on the lever 50 to open the hook 14.

The second embodiment 110 of the device is shown in Figure 4 and is similar to the first embodiment in that it has all of the main features, except that the open hook 112 has an extended lower lip 113 which terminates in a slightly curved end 115. The provision of the lower lip 113 and curved end 115 helps to prevent the attachment or tool from sliding off the hook 112 when that hook is the only hook supporting the attachment as will happen when the attachment is being attached to and removed from the device and is an important safety feature. A removable handle (not shown in Figure 4) is also used by an operator to open the latching hook 130. The handle is removably mounted over release bush 152. any suitable solid length of steel bar or rod into the bush 152.

In the event that the hollow handle becomes mislaid, the operator can insert It will of course be understood that the invention is not limited to the specific details herein described, which are given by way of example only, and that various modifications and alterations are possible with the scope of the invention as defined in the appended claims.

Claims (8)

CLAIMS:

1. An excavator tool quick attachment device of the type comprising a body with a hook at or about each end for engagement with one of a pair of connecting pins disposed on a tool, the first hook being of open construction and the second hook having a spring loaded locking means movable to lock against the pin engaged in the second hook, the locking means being spring loaded into the locked position, a retainer biased into a position to maintain the locking means in the open position, a release element at one end of the retainer adapted to be activated by the pin on the required tool engaging in the second hook, whereby when the pin comes in contact with the release element, the retainer is moved into a release position and the locking means moves into its locked position about the pin and in which a spring loaded safety means is provided which is operable to be maintained in the open position by the retainer when biased into the position to maintain the locking means in the open position, and is operable to be moved into the locked position on movement of the retainer into the position to maintain the locking means in the closed position, the safety means only being releasable from its locked position by the user pulling the safety means back into the open position against the force of its spring.

2. An excavator tool quick attachment device as claimed in Claim 1, in which the locking means is moveable back into the release position by a manually operable lever.

3. An excavator tool quick attachment device as claimed in Claim 2, in which the lever includes a removable handle and a stub or bush on which the handle is removably mounted.

4. An excavation tool quick attachment device as claimed in any one of the preceding claims, in which the locking means includes an adjustable coil spring so that the spring loading of the locking means can be adjusted over time to compensate for wear and the like. V

5. An excavation tool quick attachment device as claimed in Claim 4, in which the coil spring is mounted about a central bar so as to help to prevent material clogging the spring. 6

6. An excavator tool quick attachment device as claimed in any one of the preceding claims, in which the first hook is provided with an extended lower lip to enhance the engagement with the said supporting pin disposed on the tool.

7. An excavator tool quick attachment device as claimed in Claim 6, in which the extended lower lip is provided with a curved end.

8. An excavator tool quick attachment device substantially as herein described with reference to and as shown in the accompanying drawings. MACLACHLAN & DONALDSON Applicants’ Agents