WO2014098618A1

WO2014098618A1 - A control system

Info

Publication number: WO2014098618A1
Application number: PCT/NZ2013/000234
Authority: WO
Inventors: Andre Richard ANDERSON; Ashley Craig GIBSON; Andrew James Phillip RIDER
Original assignee: Wedgelock Equipment Limited
Priority date: 2012-12-18
Filing date: 2013-12-17
Publication date: 2014-06-26

Abstract

A control system for a quick coupler C the control system including a control valve 17 which in use feeds two hydraulic supply lines 11 and 14 to supply hydraulic pressure to a wedge actuator 20 and a locking device actuator 21 of the quick coupler C. The control valve 17 has solenoids S1 and S2 which are operable to pressurise both supply lines 11 and 14 at the same time to actuate the locking device actuator 21 without actuation of the wedge cylinder 20.

Description

Title of the Invention

A Control System

Backgrou nd to the Invention

This invention relates to a control system and more particularly a control system for a quick coupler.

Quick couplers for mounting an attachment, e.g. a bucket, to an earth working machine such as an excavator are known. It is known to hydraulically operate the quick coupler. A potential danger with an hydraulically operable quick coupler is that in the event of hydraulic failure the quick coupler can fail to retain the attachment in a working position. The consequences of this can be injury to or death of someone in the vicinity of the attachment when the coupler fails.

As is known the coupler body can have a hook shaped part into which one of the mounting pins (the front pin) of an attachment engages. Another mounting pin (the rear pin) of the attachment locates in the recess. A wedge element in the form of a wedge tongue is extendible by an hydraulically powered actuator to capture the attachment mounting pin in the recess whereby the attachment is coupled to the coupler in its working position.

Should any loss of engagement force occur (e.g. hydraulic power failure) the wedge tongue of the coupler can fail to retain the rear mounting pin in the recess. If the front pin in the hook shaped part is not retained in position the attachment can fall completely from the excavator arm. If, however, the front pin in the hook shaped part is retained by a safety lock (by say our I Lock device as described and claimed in New Zealand patent specification 552294/546893) then the attachment will not fall completely off the coupler but will swing down on the front pin retained in the hook shaped part.

Typically quick couplers have a control valve which is supplied hydraulic pressure and which is fed by two hydraulic lines running along the boom and dipper arm of the excavator, where one feed line is pressurised and the other feed line is vented to tank. In this situation the control valve will allow these lines to be switched from pressurised to vented, such that if one line is pressurised the other must be vented. This allows for extension and retraction of a double acting actuator (i.e. two states)

Most earth working machines will normally be supplied with the two hydraulic lines for operation of the coupler. However, to operate a safety locking device independently a further hydraulic feed line line has been required. Thus it can be an inconvenience especially from a cost point of view to run a third feed line to the coupler.

Summary of the Invention

An object of the present invention is thus to provide a control system for a quick coupler whereby an additional hydraulic line is not required for operation of a safety locking device of the coupler or to at least provide the public with a useful choice.

Broadly according to one aspect of the invention there is provided a control system for a quick coupler the control system includes a control valve which in use feeds two hydraulic supply lines to supply hydraulic pressure to a wedge actuator and a locking device actuator of the quick coupler characterised in that the control valve is arranged to pressurise both supply lines at the same time to actuate the locking device actuator without actuation of the wedge cylinder.

Broadly in a second aspect of the invention there is provided a quick coupler that includes a control system as defined in the first broad aspect.

Broadly according to a third broad aspect of the invention there is provided a method of controlling a quick coupler that has a wedge actuator and a locking device actuator by first and second hydraulic feed lines including the steps of (a) pressurising the first feed line and venting the second feed line to cause the wedge actuator to operate and couple an attachment to the coupler, (b) venting the first feed line and pressurising the second feed line to operate the wedge cylinder and partly release the attachment and (c) pressurise both feed lines to cause the locking device actuator to operate to fully release the attachment from the coupler.

In a preferred embodiment the wedge actuator is a double acting actuator.

In a preferred form the locking device actuator is a single acting actuator that is biased into a locking state by a mechanical biasing mechanism or element.

In a preferred form of the invention the mechanical biasing element is a spring.

Preferably in one form of the invention the control valve includes first and second solenoids.

In the preferred form the first and second solenoids are controlled by an electrical control circuit.

Preferably the control circuit includes a micro-controller and at least one switch accessible to a person operating the control system. Preferably the control valve includes pressure relief or pressure reducing valves to adjust the pressures applied to the wedge actuator when pressure is applied to both feed lines.

In one preferred form the control valve is arranged to be operable to achieve three pressurised states being :- a. A first of the two pressurised lines pressurised and a second of the two pressurised lines vented.

b. First line 1 1 vented and second line 1 4 pressurised .

c. First line 1 1 pressurised and second line 1 4 pressurised

There can be a fourth state d, which follows state c, and is achieved by the control valve wherein nothing is pressurised and the first and second lines are vented.

In another form of the invention one or more additional actuators are coupled to an hydraulic line that supplies the locking device actuator with hydraulic pressure.

In one form of the invention the control system includes a manifold that is situated with the coupler.

In the preferred form the two supply lines extend between the control valve and the manifold.

Preferably the solenoids are controlled whereby in step (a) they are both in an off state, in step (b) they are both in an on state and in step (c) one is in an off state and the other is in an on state.

In a preferred form there is a step (d) where the state of the solenoids in step (c) are reversed.

Brief Descri ption of the Drawi ng s

In the following more detailed description of one embod iment of the invention and its application to a quick coupler reference will be made to the drawings which form part of this specification and in which:-

Fig . 1 is a diagrammatic side elevation view of an excavator with an hyd raulic quick coupler mounting an attachment in the form of a bucket the excavator incorporating a control system in accordance with the present invention,

Fig . 2 is an hydraulic circuit for a two line coupler control system according to the invention,

Fig . 3 is an electrical control circuit of the control system of the invention, Fig . 4 is the circuit diagram as shown in Fig. 2 but showing modifications to form a further embodiment of the invention, and

Fig . 5 is a circuit diagram as shown in Fig. 2 but showing other modifications to form a further embodiment of the invention.

Detai led Descri ption of Preferred Em bod i me nts of the Inve ntion

According to the invention (for which a number of embodiments will herein be described) the control system for a quick coupler enables not only operation of the operating actuator for the moving element (e.g. wedge tongue) but also the actuator for a safety locking system yet only require two hydraulic lines to achieve the functionality. This is achieved by arranging for the hydraulic lines to be able to both be pressurised at the same time.

Referring firstly to Figure 1 one preferred form of the invention is shown in conjunction with an excavator machine A with a bucket B attachment coupled by a known form of quick coupler C made by our company. The quick coupler is, as known, attached to the distal end of the dipper arm D. The quick coupler C is operated hydraulically by the hydraulics of the machine A, via two hydraulic lines 1 1 and 1 4.

As is known the coupler body has a hook shaped part into which one of the mounting pins (front pin) of an attachment B engages. Another mounting pin (rear pin) of the attachment B locates in the recess. An hyd raulically powered wedge element in the form of a wedge tongue is extend ible to capture the rear mounting pin in the recess whereby the attachment is coupled to the coupler C in its working position as illustrated in Figure 1 .

Typically an excavator A will be supplied with two hydraulic control lines for hydraulic quick coupler control. One line 1 1 will extend from the pressurised hydraulic supply 1 2 while the other line 1 4 will convey hydraulic fluid, that is vented from the control rams (actuators), back to an hydraulic tank 1 5. These two lines 1 1 and 1 4 can, accord ing to the present invention, be used to operate a safety locking device of the coupler C so that a front pin of the attachment remains connected to the coupler in the event of loss of wedge engagement force due to lack of engagement force e.g. caused by hydraulic failure.

The front pin can be retained in position in the hook shaped part by a safety locking device such as our "I Lock" locking device as described and claimed in New Zealand patent specification 546893 / 552294.

A safety locking device is thus a desirable part of a coupler, however, to operate the locking device hydraulically a further hyd raulic feed line is required. The present invention, preferred embodiments of which will now be described, provides a control system whereby a further or third feed line is not required.

For the purposes of description the present invention will be described as includ ing a safety locking device in the form of the I Lock device as manufactured and sold by our company. In Figure 2 the I Lock device is indicated by reference numeral 1 6. The control system of the invention supplies hydraulic fluid under pressure to the locking device 1 6 so that it can operate as described in patent specification 546893 / 552294 (the content of which is incorporated herein by way of specific reference).

The control system consists of three parts namely a control valve 1 7, a control manifold 1 8 and an electrical system 1 9 (Figure 3).

The control valve 1 7 is connectible to hydraulic pressure supply 1 2 and feeds the two lines 1 1 and 1 4 connected thereto. These lines 1 1 and 1 4 run along the boom and dipper to the coupler C. The control valve 1 7 has two solenoid valves S I and S2 the individual states of which are controlled by the electrical system 1 9 (Figure 3). The control valve 1 7 is thus able to achieve three distinct pressurised states as will be described below.

The control manifold 1 8 is, in the preferred form, located in the quick coupler C and depending on which of the three states of the control valve 1 7 will pressurise/vent one double acting actuator 20 (the cylinder controlling extension and retraction of the coupler wedge) and one single acting actuator 21 (the safety locking device cylinder).

The electrical system 1 9 d ictates when each of the three distinct states are required based on operator input, by supplying electrical signals to the two solenoid valves SI and S2.

As can be readily appreciated from the hydraulic circuit of Figure 2 control of the solenoids SI and S2 can be achieved to create connection configurations of actuators 20 and 21 with the lines 1 1 and 1 4 to the respective pressurised hydraulic supply 1 2 and tank 1 5.

As shown the valve 1 7 is connectible via an inlet connection to supply 1 2. The inlet connection connects via line 26 to solenoid SI and line 27 to solenoid S2. A line 28 interconnects solenoid S2 to a line 29 from solenoid SI to an outlet (vent) connection which is connectible to tank 1 5.

Line 1 4 from solenoid S2 is connected to one side of the double acting cylinder 20 while line 1 1 is connected to the other end of cylinder 20. A branch 1 l a connects line 1 4 to the single acting lock actuator 21 . The following three distinct pressurised states can thus be achieved (referring to Figure 2):- a. Line 1 1 pressurised and line 1 4 vented.

b. Line 1 1 vented and line 1 4 pressurised.

c. Line 1 1 pressurised and line 1 4 pressurised.

The novelty in this invention lies in the fact that lines 1 1 and 1 4 can both be pressurised at the same time and thereby three states are achievable even though two feed lines are employed.

The electrical circuit 1 9 incorporates a micro-controller 23 for control of the solenoids SI and S2 via respective wiring 24 and 25. The micro-controller 23 thus permits the excavator operator to change the states of the solenoids SI and S2 (by way of activating inputs of two switches Al and A2) such that three different states a, b and c of connection of lines 1 1 and 1 4 to the pressurised supply 1 2 and tank 1 5 is achieved.

Accordingly when an attachment B is to be engaged manipulation of the input switch Al by the operator of the excavator can establish state "a". Thus the actuator cylinder 20 will be vented via line 1 4 by the solenoid SI connecting line 1 4 to the tank 1 5. In this state solenoid S2 connects the supply 1 2 to line 1 1 to thereby actuate cylinder 20. This state "a" is illustrated in Figure 2.

In this state "a" the action of the biasing mechanism/element 22 of the safety locking device enables the front pin to engage in the hook portion and then retain the front pin of the attachment locked in place. The pressurised line 1 1 will result in the actuation of the cylinder 20 so that the wedge element extends and captures the rear pin of the attachment located in the recess of the coupler.

A pilot check valve 30 in line 1 1 a prevents pressure supply to the lock cylinder 21 .

In the event of low or no hydraulic pressure, lack or loss of engagement force by the wedge can result in the rear pin becoming disengaged from the recess. However, the locking device will continue to retain the front pin due to the biasing mechanism/element 22 ensuring the locking effect is maintained.

When it is desired to release the attachment from the coupler the input switch Al is operated to select state "b". Thus solenoid SI is put in a state to connect line 1 1 to tank 1 5 (i.e. vent) and solenoid S2 to connect the supply 1 2 to line 1 4.

The venting by line 1 1 and pressure applied by line 1 4 causes the wedge cylinder 20 to retract the wedge. However, pressure may not enter line 1 1 a due to the pilot check valve 30 so the front pin remains locked in the hook shape portion. To finally release the attachment fully from the coupler the input switch A2 is moved to a position where state "c" is achieved. Thus solenoids SI and S2 both connect lines 1 1 and 1 4 to supply 1 2 so that both lines are pressurised.

This pressurisation of lines 1 1 and 1 4 will cause the lock cylinder 21 to operate to release the safety lock acting on the rear pin so that the attachment can be fully disconnected from the quick coupler. Because lines 1 1 and 1 4 are both pressurised the wedge cylinder 20 is effectively prevented from operation because the pressure reducing valves 31 and 32 will have been adjusted so that the load acting on opposite sides of the piston in cylinder 20 will be substantially the same.

The micro-controller 23 part of the system takes the operator controlled inputs from switches Al and A2, and decides when to turn on and off solenoids SI and S2. A switching sequence is required to achieve the states a, b and c discussed above, as detailed below:

State a: Because state a is achieved after state c (in a looping manner for attachment/detachment), solenoid S2 must be turned off before SI . If this is not done, back pressure from line LI will cause temporary activation of actuator 21 .

State b: SI must be turned on first, followed by S2. Again to avoid false activation.

State c: When leaving state c to state b, S2 must be turned off and SI on simultaneously, followed by turning S2 on again.

Figure 4 shows a different embodiment of the invention where two additional components have been added (compare with Figure 2). The addition of these components enables the system to be controlled in a simpler manner. It also allows supply flow rates to be increased (meaning actuators/cylinders can be extended/retracted at a higher speed), without the risk of false actuation of line 1 l a due to back pressure (generated by the high speed movements) in lines 1 1 or 1 4.

As shown in Figure 4 the two additional components are a check valve 31 and a pressure relief valve 32.

In this embodiment the line which supplies the pilot check valve 30 is the extend line 1 1 , which has the pressure relief valve 32 in its supply path. This pressure relief valve 32 acts as a buffer because a threshold pressure required to allow fluid to pass must be exceeded before it can supply the pilot check valve 30. This means that back pressure in the extend line 1 1 (generated by retracting the wedge cylinder 20), cannot supply the check valve 30 and activate the safety lock cylinder 21 . The check valve 31 between the lock cylinder 21 and retract line 1 4 allows fluid to drain to this line (as drainage is not possible back through the relief valve 32). In this

embodiment the pilot check valve 30 is piloted by the retract line 1 4. Activation of the modified circuit, according to the embodiment of Figure 4, may now be achieved as below:

• State a: Wedge cylinder 20 extended/pressurised

o Line 1 1 pressurised, line 14 vented,

o Solenoids SI and S2 both off.

• State b: Wedge cylinder 20 retracted

o Line 1 1 vented, line 1 4 pressurised,

o Solenoids SI and S2 both on.

• State c: Lock cylinder 21 pressurised

o Lines 1 1 and 1 4 both pressurised,

o Solenoid SI off and solenoid S2 on.

• State d: Nothing pressurised - used to transition between states a, b, and c.

o Lines 1 1 and 1 4 both vented.

o Solenoid SI on and solenoid S2 off.

It is possible for multiple single acting actuators/cylinders 21 a and 21 b to be attached to the branch or safety line 1 l a, thus giving more than one function (as shown in Figure 5). Such actuators/cylinders 21 a, 21 b etc might be used for example to move locking components used in a locking system such as, for example, described and claimed in New Zealand patent specification 6041 1 0. Such actuators 21 a, 21 b ... would be sprung to return to their original position when hydraulic pressure is not present.

Although in the first embodiment described herein there is reference to the use of two switches Al and A2 (see Figure 3) to control when the system is put into state c, other embodiments would not be so restricted. For example, the safety input A2 could be activated by some other means, such as a sensor input. Furthermore, the safety input could be removed completely such that the internal program of the micro-controller 23 dictates that events should take place after a designated time period. The relevant consideration is that two solenoid coils SI and S2 are energised on and off by an electrical system in order to dictate if they are both pressurised at the same time, which controls the state of the hydraulic system between states a, b, c, and d.

The present invention thus provides a control system that is operable such that control of the coupler wedge and the safety locking device is achievable using two rather than three lines. Thus the control system enables three states to be achieved yet only using two feed lines. As described above this is achieved by having both feed lines pressurised at the same time.

The present invention has been described and illustrated by way of specific embodiments, and the embodiments have been described in detail in relation to a known quick coupler and safety lock device. It is not the intention of the Applicant to restrict or in any way limit the scope of the invention to such detail. Additional advantages and modifications will be readily apparent to those skilled in the art.

Therefore, the invention in its broader aspects is not limited to the specific details, representative means of manufacture and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of the Applicant's general inventive concept.

Claims

CLAIMS:-

1 . A control system for a quick coupler the control system includes a control valve which in use feeds two hydraulic supply lines to supply hyd raulic pressure to a wedge actuator and a locking device actuator of the quick coupler characterised in that the control valve is arranged to pressurise both supply lines at the same time to actuate the locking device actuator without actuation of the wedge cylinder.

2. A control system as claimed in claim 1 wherei n the wedge actuator is a double acting actuator.

3. A control system as claimed in claim 1 or 2 wherein the locking device actuator is a single acting actuator that is biased into a locking state by a mechanical biasing mechanism or element.

4. A control system as claimed in claim 1 , 2 or 3 wherein the mechanical biasing element is a spring.

5. A control system as claimed in any one of the preceding claims wherein the control valve includes first and second solenoids.

6. A control system as claimed in claim 5 wherein the first and second solenoids are controlled by an electrical control circuit.

7. A control system as claimed in claim 6 wherein the control circuit includes a micro-controller and at least one switch accessible to a person operating the control system.

8. A control system as claimed in any one of claims 5 , 6 or 7 wherein the control valve includes pressure relief or pressure reducing valves to adjust the pressures applied to the wedge actuator when pressure is applied to both feed lines.

9. A control system as claimed in any one of claims 5 , 6 or 7 wherein the control valve is arranged to be operable the achieve three pressurised states being:- a. A first of the two pressurised lines pressurised and a second of the two pressurised lines vented.

b. First line 1 1 vented and second line 1 4 pressurised.

c. First line 1 1 pressurised and second line 1 4 pressurised

1 0. A control system as claimed in claim 1 0 wherein a fourth state d which follows state c is achieved by the control valve wherein nothing is pressurised and the first and second lines are vented.

1 1 . A control system as claimed in any one of the preceding claims further including one or more additional actuators coupled to an hydraulic line that supplies the locking device actuator with hyd raulic pressure.

1 2. A quick coupler that includes a control system as claimed in any one of the preceding claims.

1 3. A quick coupler as claimed in claim 1 2 wherein the control system includes a manifold that is situated with the coupler.

1 4. A quick coupler as claimed in claim 1 3 wherein the two supply lines extend between the control valve and the manifold.

1 5. A method of controlling a quick coupler that has a wedge actuator and a locking device actuator by first and second hydraulic feed lines including the steps of (a) pressurising the first feed line and venting the second feed line to cause the wedge actuator to operate and couple an attachment to the coupler, (b) venting the first feed line and pressurising the second feed line to operate the wedge cylinder and partly release the attachment and (c) pressurise both feed lines to cause the locking device actuator to operate to fully release the attachment from the coupler.

1 6. The method as claimed in claim 1 5 wherein following step (c) there is a fourth step (d) when nothing is pressurised and the first and second feed lines are vented.

1 7. The method as claimed in claim 1 5 or 1 6 wherein the solenoids are controlled whereby in step (a) they are both in an off state, in step (b) they are both in an on state and in step (c) one is in an off state and the other is in an on state.

1 8. The method as claimed in claim 1 7 wherein in step (d) the state of the solenoids in step (c) are reversed.

1 9. A control system for a quick coupler substantially as herein described with reference to the accompanying drawings.

20. A quick coupler substantially as herein described with reference to the accompanying drawings.

21 . A method of controlling a quick coupler that has a wedge actuator and a locking device actuator as claimed in claim 1 5 and as substantially herein described.