CN101331278A - Safety equipment for hydraulic coupling assemblies - Google Patents

Abstract

A safety device for use with a hydraulic hitch assembly operable between engaged and disengaged positions, the safety device comprising: a body portion movable between engaged and disengaged positions, whereby when the body portion is in the engaged position, the safety device prevents the hydraulic hitch assembly from moving to the disengaged position; a biasing device biasing the body portion towards an engaged position; and a hydraulic piston which, when operated, acts on the biasing means and moves the body portion to the disengaged position.

Description

Safety equipment for hydraulic coupling assemblies

technical field

The present invention relates to a safety device for a hydraulic coupling assembly, in particular to a safety device operable remotely from the coupling assembly.

Background technique

Large mobile machines such as excavators are usually equipped with various additional devices to improve the versatility of the machine. Examples of such attachments include buckets or rock hammers. Typically, these attachments are mounted on the articulated arm of the excavator by means of a quick change device, such as a hitch assembly or quick coupler, usually hydraulically actuated.

In Australian Patent No. 586124 a hydraulic coupling assembly is described which includes a pair of opposing jaws which are remotely operable and adapted to move between engaged and disengaged positions. In the disengaged position, said pawl can fit between the internal transverse hinge pins of the attachment. Then, using hydraulic pistons or cylinders, the jaws are moved away from each other into an engaged position where they grip the transverse hinge pin of the attachment and hold it in place for use.

Due to the risk of a hydraulic failure in which the hydraulic coupling assembly may almost immediately retract to the disengaged position, hydraulic coupling assemblies are required to be fitted with safety limiting devices which will prevent the coupling assembly from being released from the attachment. These safety limiting devices are typically mechanical devices that require a machine operator to engage and disengage the safety device at the location of the coupling assembly. As such, this means that every time the attachment is changed, the operator must step down from the cab operating the machine to disengage the safety equipment. The operator then needs to go back up into the cab to operate the hydraulically actuated hitch assembly to change the attachment of the hitch assembly, after which the operator has to come down out of the cab again to re-engage the safety limiting device.

Accordingly, the present invention seeks to provide a safety device for use in a hydraulic coupling assembly, and in particular seeks to provide a safety device operable from the operator compartment of the machine comprising the coupling assembly.

Contents of the invention

According to one aspect, the present invention provides a safety device for a hydraulic coupling assembly operable between engaged and disengaged positions, said safety device comprising:

a body portion movable between an engaged position and a disengaged position whereby a safety device prevents the hydraulic coupling assembly from moving to the disengaged position when the body portion is in the engaged position;

biasing means that biases the body portion toward the engaged position; and,

A hydraulic piston which, in operation, acts on the biasing means and moves the body part to the disengaged position.

Preferably, the body portion moves between an engaged position and a disengaged position about a pivot point.

Preferably, said biasing means is provided as a mechanical means such as a spring.

The hydraulic coupling assembly is operable between a disengaged position and an engaged position by a hydraulic cylinder or piston. In this form, a hydraulic cylinder or piston is operated by a hydraulic circuit wherein, to move the coupling assembly into the engaged position, hydraulic fluid is drawn under pressure into one side of the cylinder or piston to effectuate the movement. Once in the engaged position, a valve assembly contained in the hydraulic circuit prevents the hydraulic cylinder or piston from moving the coupling assembly to the disengaged position. Preferably, the valve assembly is in the form of a non-return valve. The valve assembly prevents movement of the cylinder or piston until positive hydraulic pressure is applied to the valve assembly, whereby the cylinder or piston releases, allowing the coupling assembly to return to the disengaged position.

Preferably, said hydraulic piston of said safety device is also connected to said hydraulic circuit of said coupling assembly. More preferably, said positive pressure applied to said valve assembly to release said hydraulic piston and/or cylinder to allow said coupling assembly to return to said disengaged position is initially applied to said on the hydraulic piston, thereby moving the body portion of the safety device to the disengaged position before the coupling assembly returns to the disengaged position.

According to another aspect, the present invention provides a method of disengaging a hydraulic coupling assembly including a safety device from an engaged position, wherein the method comprises the steps of:

(i) providing positive pressure to said hydraulic piston of said safety device sufficient to overcome said biasing means and move said safety device from an engaged position to a disengaged position; and

(ii) moving the hydraulic coupling assembly to a disengaged position.

Description of drawings

The invention will be better understood from the following detailed description of preferred but non-limiting embodiments described in conjunction with the accompanying drawings, in which:

Figure 1 is a schematic diagram of a security device according to an aspect of the present invention,

Figure 2 is a schematic diagram of a hydraulic coupling assembly,

Figure 3 is a schematic illustration of a hydraulic coupling assembly incorporating a safety device in an engaged position according to an aspect of the present invention, and,

Figure 4 is a schematic illustration of a hydraulic coupling assembly incorporating a safety device in a disengaged position according to an aspect of the present invention.

Detailed ways

The term "hydraulic coupling assembly" as used throughout this specification is intended to include quick couplings as well as any type of hydraulic assembly used to connect and disconnect various attachments to and from large machinery.

Referring to Figure 1, a safety device that may be connected to a hydraulic coupling assembly is shown. The safety device 10 includes a generally elongated body portion 12 and includes an engagement end 85 and a pivot point 15 . The safety device 10 also includes a spring 20 which in this illustration is biased against a retaining block 45 which is fixed relative to the main body of the hydraulic coupling assembly (not shown in FIG. 1 ). The safety device 10 also includes a hydraulic piston 35 having a hydraulic fluid space 25 for receiving hydraulic fluid under pressure to operate the hydraulic piston 35 . The hydraulic piston 35 is shown resting on a retaining block 40 which is also connected and fixed relative to the body portion of the hitch assembly and is not connected to the body portion 12 of the safety device 10 . In an alternative embodiment, the retaining block may be connected to the body portion of the hydraulic cylinder 70 associated with the hydraulic coupling assembly.

Referring now to Figure 2, there is generally shown a hydraulic coupling assembly indicated generally at 51 for coupling an attachment, such as a bucket or rock hammer, to a heavy machine, such as an excavator, for example. The coupling assembly 51 includes two remotely operable opposing jaws 60, 65 that are movable between an engaged position (as shown in FIG. 2) and a disengaged position. In the disengaged position, the counter pawls 60 and 65 are able to fit between the transverse hinge pins 50 and 55 of a particular attachment, thereby releasing the attachment. Once engaged with the attachment, the jaws 60 and 65 are pushed away by a hydraulic cylinder 70 operable from the machine compartment, which pushes the jaws 60 and 65 away until the attachment is firmly secured to the coupling assembly 51 .

Although not shown in FIG. 2, hydraulic cylinder 70 is operated by a hydraulic circuit, the operation of which hydraulic fluid is drawn into hydraulic cylinder 70, which in turn moves jaw 65 away from jaw 60 to engage the attachment, at This position check valve shuts off hydraulic fluid from the main hydraulic circuit, thereby keeping the dogs 65 and 60 engaged. To open the check valve and thereby disengage the hydraulic coupling assembly 51, positive pressure must be applied to the check valve to release the hydraulic cylinder 70, thereby allowing the jaws 65 to return to the disengaged state.

Referring now to Figure 3, there is shown a safety device 10 installed in conjunction with a hydraulic coupling assembly. The safety device 10 and hydraulic hitch assembly are shown in an engaged position whereby the attachment is securely secured to the hitch assembly. In the event of a hydraulic failure, hydraulic cylinder 70 will release, thereby allowing jaw 65 to retract toward jaw 60 . In this case, the engagement point 85 of the safety device will engage the engagement notch 80 of the hitch assembly 51, thereby preventing the pawls 60 and 65 from moving together beyond a distance that would allow the attachment to be disengaged from the hitch assembly.

The safety device 10 is hinged relative to the linkage assembly 51 at a fixed point 15, where the safety device can be rotated about point 15 between an engaged position and a disengaged position. When the hydraulic coupling assembly 51 is in the engaged position, the spring 20 of the safety device 10 presses the safety device into the engaged position by pushing against the retaining block 45 connected and fixed relative to the coupling assembly 51 .

In order to disengage the safety device from this position, it is necessary to supply pressurized hydraulic fluid to the cavity 25 of the hydraulic piston 35 located in the safety device 10 . Once sufficient pressure is applied to the fluid, the hydraulic piston 35 pushes down onto the retaining block 40 which is also connected and fixed relative to the body portion of the hitch assembly, thereby pushing the safety device against the biasing force of the mechanical spring 20 . As soon as the hydraulic piston 35 pushes against the retaining block 40 with a force greater than the spring force of the spring 20, this causes the safety device to rise and move around the hinge point 15 so that the device moves to the disengaged position.

Referring now to Figure 4, the safety device 10 is shown in the disengaged position whereby the hydraulic piston 35 of the safety device 10 has pushed against the retaining block 40 connected to the hitch assembly thereby moving the safety device 10 to the disengaged position. It can be seen that, in the disengaged position, the engagement point 85 of the safety device 10 is no longer aligned with the corresponding engagement notch 80 of the coupling assembly, so that once the hydraulic coupling assembly's hydraulic cylinder is allowed to release and move the hydraulic coupling assembly 51 to the disengaged position, This allows the jaws 60 and 65 to retract.

A definite advantage of the safety device 10 is that, in order to release the device and allow the jaws 60 and 65 of the hitch assembly 51 to retract to the disengaged position, it can be accessed from a point remote from the hitch assembly, such as the operator compartment of the heavy machine. The hydraulic piston 35 of the safety device 10 is operated.

As a further advantage of this arrangement, the hydraulic fluid that operates hydraulic piston 35 may be part of the hydraulic circuit associated with hydraulic coupling assembly 51 . In this form, the back pressure applied to the hydraulic cylinder 70 of the check valve for releasing the coupling assembly 51 is initially directed towards the hydraulic piston of the safety device 10, causing the safety device to move just before the hydraulic cylinder 70 of the coupling assembly 51 is released. to the disengaged position. In this way, the safety device 10 can be manipulated from the operator's compartment of the shovel or the like, thereby eliminating the need for an operator to step down from the operator's compartment in order to disengage the safety device for removal and connection of various attachments to the hydraulic coupling assembly.

Furthermore, this arrangement provides the added safety advantage that if there is indeed a hydraulic failure causing the hydraulic coupling assembly to retract, the safety device cannot be moved to the disengaged position as such movement would require hydraulic pressure to do so. Thus, in the event of a hydraulic failure, the safety device remains engaged.

To help the operator of an excavator or the like equipped with the safety device of the present invention determine whether the safety device 10 is in the engaged or disengaged position, the safety device may also be provided with a display device (not shown in the drawings). In one form, the display means may be in the form of two flanges, one extending from the engaging end of the security device 10 and the other extending from the end adjacent the pivot point 15 . When the safety device is in the engaged position, the flange is arranged such that the flange has a specific configuration when viewed from the operator's cab of the excavator such that the operator can be assured that the safety device is in the engaged position. Once the safety device is moved to the disengaged position, the flanges are no longer aligned with the specified configuration, indicating that the safety device is no longer in the engaged position. In an alternative embodiment, the display means may be located in the actual operating compartment of the excavator or the like and take the form of, for example, lights which, when operated, provide an indication to the operator whether the safety device is engaged or disengaged.

Examples of embodiments of the invention are as follows:

The check valves associated with the hydraulic cylinders of a typical hydraulic coupling assembly operate at a 3:1 ratio, ie the check valves are capable of providing 3000 PSI of restrained pressure which will hold the hydraulic coupling assembly in the engaged position. Since the check valve operates at a 3:1 ratio, it requires 1000 PSI of back pressure to unclamp, after which the hydraulic coupling assembly will retract to the disengaged position. In this example, a backpressure of 1000 PSI is provided to the hydraulic piston of the safety device prior to being applied to the check valve and is sufficient to operate the hydraulic piston to overcome the force of the biasing device, thereby moving the safety device to the disengaged state and allowing The coupling assembly is moved to the disengaged position.

For various reasons, such as the presence of hydraulic pressure bypasses, compromised seals of the hydraulic cylinders, or contamination in the hydraulic fluid, the conditioned pressure of the hydraulic cylinders holding the coupling assembly may drop. In this case, the pressure required to unclamp the check valve will also drop in a 3:1 ratio, whereby the pressure required to unclamp the check valve will not be sufficient for the hydraulic piston of the safety device to overcome the bias The force of a device such as a spring. This means that the safety device cannot be moved into the disengaged position, requiring constant monitoring of the safe working condition of the hydraulic coupling assembly.

Finally, it is to be understood that the inventive concept of the present invention in any of its aspects can be incorporated into many different configurations, so that the generality of the foregoing description is not superseded by the specificity of the accompanying drawings. Various alterations, modifications and/or additions may be incorporated into various configurations and arrangements of components without departing from the spirit or scope of the invention.

Claims (10)

CLAIMS 1. A safety device for use with a hydraulic coupling assembly operable between engaged and disengaged positions, said safety device comprising: a body portion movable between an engaged position and a disengaged position whereby a safety device prevents the hydraulic coupling assembly from moving to the disengaged position when the body portion is in the engaged position; biasing means that biases the body portion toward the engaged position; and, A hydraulic piston which, in operation, acts on the biasing means and moves the body part to the disengaged position. 2. The safety device of claim 1, wherein the body portion moves between an engaged position and a disengaged position about a pivot point. 3. The safety device of claim 2, wherein the pivot point is fixed relative to the hydraulic coupling assembly. 4. A safety device as claimed in claim 2 or 3, wherein the pivot point is located at one end of the body portion. 5. A safety device as claimed in any one of claims 1 to 4, wherein the biasing means is a spring. 6. A safety device as claimed in any one of claims 1 to 5, wherein said hydraulic coupling assembly is operable between a disengaged position and an engaged position via a hydraulic cylinder, said hydraulic cylinder being operable via a hydraulic circuit contained hydraulic fluid to operate. 7. A safety device as claimed in claim 6, wherein the hydraulic piston of the safety device is operated by hydraulic fluid contained within the hydraulic circuit of the hydraulic coupling assembly. 8. The safety device of claim 7, wherein a hydraulic piston of the safety device is provided with hydraulic fluid at a positive pressure just prior to operating the hydraulic cylinder to move the hydraulic coupling assembly to the disengaged position, the positive pressure sufficient pressure to move the safety device to the disengaged position. 9. A safety device as claimed in any one of claims 1 to 8, wherein the safety device includes display means for providing an indication to an operator whether the safety device is in an engaged position or disengaged open position. 10. A method of disengaging a hydraulic coupling assembly comprising a safety device as claimed in any one of claims 1 to 9 from an engaged position, the method comprising the steps of: (iii) providing a positive pressure to the hydraulic piston of the safety device sufficient to overcome the biasing means and move the safety device from the engaged position to the disengaged position; and (iv) moving the hydraulic coupling assembly to a disengaged position.

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