GB1594923A

GB1594923A - Automatic quick-coupling device

Info

Publication number: GB1594923A
Application number: GB145778A
Authority: GB
Original assignee: Renholmens Mekaniska Verkstad AB
Current assignee: Renholmens Mekaniska Verkstad AB
Priority date: 1978-01-13
Filing date: 1978-01-13
Publication date: 1981-08-05

Description

(54) AUTOMATIC QUICK-COUPLING DEVICE (71) We, RENHOLMENS MEKANISKA VERKSTAD AB, a Swedish joint-stock Company of Fack S-930 47 Byske, Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a coupling between a tool attachment carried by a tractor or other tool carrier, and a tool, and particularly to a coupling between an attachment and a tool of the kind which can be hydraulically manipulated from the tool carrier.

Known coupling of this kind have been found to provide only the facility of mechanically locking the tool attachment to the tool.

For tools having hydraulic functioning abilities it has heretofore been necessary to carry out the coupling of the hydraulic control system by manually connecting a number of hoses together. This to some extent takes away the advantage of the mechanical locking, because the driver still has to leave the cab or tractor to couple, the hydraulic control system.

It is therefore an object of the present invention to solve this problem and to provide a coupling in which the hydraulic control system of a tool can be automatically coupled to that of a tool attachment at effectively the same time as the tool attachment mechanically is being locked to the tool.

In accordance with this invention there is provided a coupling between a tool attachment adapted to be supported on a carrier and a tool mounting means adapted to carry a hydraulically operable tool, the coupling comprising mechanical locking means and hydraulic connecting means, the mechanical locking means comprising a fixed latch member attached to the tool mounting means, a movable latch member supported on the tool attachement and means for moving the movable latch member into engagement with the fixed latch member when the tool attachment and tool mounting means are in a coupling position, and the hydraulic connecting means comprising a pair of twopart hose couplings, one part of each pair being fixed on said tool mounting means and the other part of each pair being movably supported on said tool attachment, and means for moving said other part of each pair into hydraulic coupling with said one part, means being provided to allow coupling of the hydraulic connecting means only after coupling of mechanical locking means has been effected and to allow decoupling of the mechanical locking means only after decoupling of the hydraulic connecting means has been effected.

The invention is further described hereinafter, by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a lateral view of a tool attachment of a tractor and of a tool having mounting means for effecting attachment of the tool to the tractor by means of a coupling in accordance with the invention; Fig. 2 is an end view of the mounting means of the tool looking in the direction of the arrow 11 in figure 1.

Fig. 3 is an end view, partially in section and in the direction of the arrow III in figure 1. of the tool attachment illustrating in part a first embodiment of the coupling; Fig. 4 is an end view similar to that shown in Fig. 3, but of a modified coupling; Figs. 5 and 6 show certain parts of another coupling in accordance with the invention, in disengaged and coupled position, respectively; Fig. 7 is a schematic diagram of the hydraulic circuit employed in coupling according to the invention; Fig. 8 is another schematic diagram of the hydraulic circuit particularly employed with the coupling illustrated in Figs. 5 and 6 and Figs. 9, 10 and 11 are further hydraulic circuit diagrams for alternative embodiments of the invention.

In the drawings Fig. 1 illustrates the position just prior to the coupling of a tool attachment 1 disposed on a tractor (not shown) and a tool 6 which in the present example is a timber grapple. The tool attachment 1 is pivoted about a hinge 2 disposed in the end of a lifting arm 3 of the tractor.

Pivotal movement of the tool attachment is effected by means of hydraulic rams (not shown) connected to a tilt arm 5 which is pivotally connected to the attachment tool 1 at some distance from the hinge 2. On the tool 6 is disposed mounting means 7 comprising a hook 8 which is adapted to engage with a lifting boom 11 (see Figs 3 and 4) of the tool attachment 1 when, in the position shown in fig. 1, the tractor is moved toward the tool and the tool attachment is lifted.

On further lifting of the tool attachment 1, the opposing, correspondingly shaped, surfaces 10 of the tool attachment 1 and mounting means 7 come together in a butting juxtaposition. At this point eyes 9 on the mounting means become aligned with locking pins 12 (see fig. 3) which are guided in sleeves 14 disposed in struts 13 of the tool attachment 1. In figs. 3 and 4 the eyes 9 of the mounting means 7 are not shown but the locking pins are shown in their locking and open positions respectively. Thus when the tool and tool attachment are initially coupled the locking pins would be in the position shown in figure 4. Each of the two locking pins 12 is connected to respective pistons 15 disposed in each end of a double-acting hydraulic cylinder 16.

Connections (not shown) exist for supplyhydraulic oil either between the two pistons 15 or at each end of the cylinder between each endwall thereof and each piston 15.

Thus when hydraulic oil under pressure is fed into the cylinder 16 between the two pistons 15, the pistons are moved away from each other. If the eyes 9 of the mounting means 7 have previously been positioned between the guide sleeves 14, then the two locking pins 12 then lock the holding eyes 9 However, if hydraulic oil is supplied under pressure to the two ends of the cylinders 16, the two pistons 15 are moved towards one another and the mechanical locking is released, so that the tool attachment 1 can then be removed from the tool 6. In the embodiment shown in Figure 3 the locking pins 12 cooperate with coaxial guide pins 20, which are axially movably supported at either side of the tool attachment 1 in slide bushings 21. The slide bushings 21 are attached to the struts 13 which also carry a second set of slide bushings 19 in which axially movable drawing bars 22, 23 are supported. Each drawing bar is attached to their respective guide pins 20 by intermediate pieces 24 and each is urged in a direction of parallel to the movement of the respective guide pin 20 by a spring 25 or equivalent which is disposed between the intermediate piece 24 and a plate 26 attached to the struts 13. A projection 27 on the plate 26 holds the spring 25 in position. The drawing bars 22, 23 are connected to coupling pieces 28 having male portions 30a and 29a (the latter being visible in Fig. 4) which are adapted to mate with female portions 30b and 29b respectively (see fig. 2) attached to the mounting means 7. The male and female portions 30a, 30b and 29a, 29b are hydraulic hose couplings of the quick-coupling type and need only be pressed towards one another to form a hydraulic connection. In the present embodiment the drawing bar 22 is connected to the coupling piece 28 carrying the male portion 29a, while the drawing bar 23, which, over some of its length, runs beside the drawing bar 22, is connected to the coupling piece 28 carrying the male portions 30a.

When the tool attachment is to be coupled with the tool mounting means the following procedure is adopted.

In Figure 1 the tractor carrying the tool attachment 1 is positioned so as to engage the carrying boom 11 with the hooks 8 on the mounting means 7 and the tractor further positioned so that the surfaces 10 align side by side. At which point the eyes 9 on the tool mounting means 7 also align with the slide bushings 14, the locking pins 12 at this stage being withdrawn towards one another from the position shown in Figure 3. When alignment has been achieved the operator of the tractor causes by means not shown hydraulic fluid to enter the centre of the cylinder 16 and force the pistons 15 apart. Thus the locking pins 12 are caused to engage with the eyes 9 and hence the tool mounting means 7 becomes locked onto the tool attachment. On further movement of the locking pins 12 the guide pins 20 are urged against the action of the spring 25 away from the centre of the tool attachment. This movement is transferred via the intermediate pieces 24 and drawing bars 22, 23 to the coupling pieces 28 which thereby move towards one another. The tool attachment and mounting means being locked together has also caused the female portions 29b and 30b shown in figure 2 to be aligned with the male portions 29a and 30a respectively. The female portions 29b and 30b are mounted on a guide block 36 which has hydraulic hose couplings (not shown) connected to hydraulic hoses leading to the tool itself. The guide block 36 is resiliently suspended by means not shown in a holder 37 attached to the mounting means 7. Thus when the tool attachment and tool mounting means were first coupled, the guide block 36, which has a beveled end portion, engaged with a corresponding guide slot 38 in the tool attachment and the female portions located in grooves 39 in the guide slot 38.

The two coupling pieces 28 moving towards one another therefore causes the male and female portions 29a and b and 30a and b mate together to form hydraulic couplings. The couplings are protected in shrouds 31 and hydraulic hoses, depending from the coupling pieces 28, pass through holes 34 in a cover plate 35 and connect to the hydraulic system (not shown) of the tractor. Thus an automatic coupling of the hydraulic control system for the hydraulic cylinder or cylinders of the tool can be effected. The embodiment of the inven tidn shown in Figure 4 differs from the embodiment shown in figure 3 only in that in this embodiment each of the two intermediate pieces 24 are directly connected to a locking pin 12. Each intermediate piece is axially slidably connected to respective drawing bars 22, 23, which are actuated by compression springs 51. The springs 51 are disposed in sleeves 54 in the struts 13 and damped between a detachable plate 52 and a support portion 53 connected to the end of each drawing bar. Thus when the locking pins 12 are moved apart and into the guide sleeves 14 for locking the holding eyes 9 on the mounting means 7 of the tool, the intermediate pieces 24 slide along their associated drawing bar 22 or 23 until they abut the respective support portions 53.

Thereafter the drawing bars are actuated and effect the coupling of the male and female portions as in the embodiment described with reference to figure 3. In both embodiments, when coupling is achieved the springs 25 and 51 are tightened so that when the coupling is to be released these springs ensure that the male and female portions become disengaged. From the drawings it is quite clear that, on disconnection, the hose couplings are disengaged before the locking pins are withdrawn from the sleeves 14.

In Figure 7 a hydraulic circuit diagram, applicable to the above described the embodiments is shown.

In Figure 7, a hydraulic cylinder 40 of the tool is shown and this is connected via conduits 41 and 42 when the male portions 29a and 30a are to the female portions 29b and 20b, respectively. When the male portions 29a and 30a are coupled with their respective female portions, hose connections 29 and 30 are formed which allow the flow of hydraulic oil in either direction once the relief valves dispose in each male and female portion are opened on coupling thereof.

conduits 43 and 44 lead from the male portions 29a and 30a respectively to a control valve 45 provided in the tractor or tool carrier. The control valve 45 has two operational positions A and B and a neutral position 0 and is connected via a conduit P to an oil pump and via a return conduit T to an oil tank. A connecting conduit 46 leads to the two ends of the hydraulic cylinudder 15 from the conduit 44. The conduit 43 is connected to the hydraulic cylinder 16 between its two pistons 15 via a pilot-con trolled check valve 47. For the control of the check valve A7 a control valve 48 is provided, which is coupled between the conduits 43 and 44 and electrically operated by a remote control means 48a provided in the tractor.

The control valve 48 has two positions I and II, and is connected to the check valve 47 via a pilot conduit 49. In the connection between the control valve 48 and the conduit 43 a check valve 50 is provided which prevents fluid pressure in the conduit 43 from relieving pilot pressure possibly remaining in the check valve 47 when the control valve 48 is in position 1. Thus the valve 47 is held safely closed.

When coupling is to effected the control valve 45 is set in position A so that hydraulic oil under pressure is pumped via the conduit P and conduit 43 into the hydraulic cylinder 16 between its pistons 15. The pistons 15 are thereby moved apart and bring about the mechanical locking of the tool mounting means to the tool attachment, and the coupling of the male and female portions of the two hose couplings, in the aforedescribed way. Prior to coupling together of the hose couplings flow of the hydraulic oil in the conduit 43 is prevented by the check valve provided in the male portion 29a of the hose coupling 29.

As already mentioned the female portions of the two hydraulic hose couplings also provided are with check valves which prevent hydraulic oil in the hydraulic system of the tool leaking out when the tool is not engaged.

Once coupling of the two hose couplings 29 and 30 has been effected, oil under pressure in conduit 43 enters the hydraulic cylinder 40 to move the tool in one direction. By switching the control valve 45 to position B, oil is then fed via the conduit 44 to the other side of the piston in the cylinder 40 which is thereby forced to move in the opposed direction. The control valve 48 is in the position 1.

When in position B the control valve 45 directs oil under pressure via the conduits 44 and 46 into the ends of the pistons 15 in the cylinder 16. However the pistons do not move because the oil in the centre of the cylinder 16 cannot be evacuated owing to the interference of the check valve 47. When the tool is to be detached from the tool attachment, the control valve 45 is placed in the position B and the control means 48a is switched to move the control valve 48 to its position II. In this position oil under pressure is fed via pilot conduit 49 to the check valve 47 which is thereby opened. Thus the hydraulic oil in the centre of the cylinder 16 can be evacuated via conduit 43 and the oil under pressure in conduits 44 and 46 can now succeed in moving the two pistons 15 towards one another. When the pistons 15 move toward each other, the locking pins 12 dis- iengage-from their respective guide pins 20, thereby rendering it possible for the springs 25 to move the drawing bars 22 and 23 so as to uncouple the male and female portions of the hose connections 29 and 30. On further movement of the pistons 15 the locking pins 12 release the holding eyes 9 on the mounting means 7 of the tool and the tool is mechanically disengaged from the tractor.

Figs. 5 and 6 show a modification of the embodiments so far described. In this embodiment, on each piston 15 of the hydraulic cylinder 16 a guide roller 55 is supported between the cylinder proper and the locking pin 12. The guide roller 55 abuts a guide surface 56 on an arm 58 which is pivotal about an axle 57 and which by means of a pressure roller 59, abuts a stop portion 60 on the coupling piece 28.

The coupling portion 28 with its male portion 29a is slidably mounted in a bushing 61 in the strut 13, and between the bushing 61 and a washer 62 on the coupling piece 28 a spring 63 is clamped, which tends to press the coupling piece 28 against the pressure roller 59, and therewith the arm 58 against the guide roller 55. Directly in front of the male portion 29a the female portion 29b is shown to be disposed. When hydraulic oil under pressure is supplied between the pistons 15 of the hydraulic cylinder 16, the locking pins are moved into their respective holding eyes and at the same time the guide rollers 55 move along the guide surface 56.

The arms 58 are thereby forced to pivot about their axles 57 and urge the coupling pieces 28, against the action of the compression spring 53 which are thus stressed, and to make the male portions 29a and 30a with their respective female portions 29b and 30b. This coupled position of the hose connections is illustrated in Fig. 6. Upon movement of the guide rollers 55 in the other direction the compressive springs 63 can disengage the respective hose coupling and thereby the hydraulic connection to the hydraulic cylinders of the tool is broken.

In fig. 8 a hydraulic circuit diagram is shown which is especially intended for the embodiment shown in Figs. 5 and 6. A twoposition six-way valve 65 is used in this case to which the conduits 43 and 44 leading to the hose couplings 29 and 30 are connected.

Via conduits 66 and 67 the valve 65 is also coupled to the control valve 45 disposed and controlled in the tractor. The hydraulic cylinder 16 is directly connected to the valve 65 via conduits 68 and 69. In the position shown in Fig. 8 in which the hose connections 29 and 30 are shown coupled, hydraulic oil under pressure can flow from the valve 65 via the outlet 1, conduit 43 hose coupling 29 and conduit 41 into the hydraulic cylinder 40 of the tool. The return oil from the cylinder flows via the conduit 42, hose coupling 30 and conduit 44 to the inlet 2 in the valve 65. When the opposite direction of movement for the piston of the hydraulic cylinder 40 is desired, the control valve 45 is moved from the position B shown to the position A.

Coupling of the tool attachment 1 to the tool mounting means is effected by setting in the position in which the ports line up with conduits 69 and 68 and by setting the control valve 45 in position A. For disconnecting said attachment, the control valve 45 is simply moved to position B while the valve 65 is in position 3-PGiic circuit diagram 3.

In fig. 9 a hydraulic circuit diagram for another modified embodiment is shown which differs from the previous embodiments in the location of the hose couplings 29, 30.

As appears from Fig. 9, one part of each hose connection, for example the male portions 29a, 30a is attached to the end of each locking pin 12. The second part of each hose coupling, the female portions 29b 30b, is attached to the tool mounting means adjacent the eyes 9 and in line with the respective locking pins when coupling is effected. The male portions 29a 30a are moved into the coupling positions shown in Fig. 9 after the locking pins 12 have passed through the eyes 9 and thus after mechanical coupling of the tool has been effected. The conduits 43, 44 from the valve 65 are each connected to a locking pin 12, of more precisely, to a passageway 70 formed inside each locking pin.

Thus in Fig. 9 in which the hose coupling 29 and 30 are connected, hydraulic oil under pressure can flow from the valve 65 via the outlet 1, conduit 43, passageway 70, hose coupling 29 and the conduit 41 connected to the female portion 29b of said coupling portion 29 into the hydraulic cylinder 40, from which the return oil from the other side of the piston flows to the inlet 2 of the valve 65 via the conduit 42, hose coupling 30, passageway 70 in the locking pin 12 and the conduit 44. The conduits 43 and 44 should be of flexible type for being able to accommodate the movement of the locking pins.

Coupling and uncoupling is effected in the same was as for the embodiment descibed with reference to figure 8. In figure 10 an embodiment is shown in which the tool is provided with two working cylinders 100 and 100a. The hydraulic cylinder 100 is connected via conduits 102, 103 to a pair of hose couplings 104, 105, which are connected and disconnected each by means of a control device 106, which are controlled electrically via a control valve 107 from a control panel 108. The hydraulic cylinder 100a is connected in a similar way to a pair of hose couplings 104a 105a, which are connected and disconnected each by mearis of a control device 106a, which are controlled electrically via a control valve 107a from the control panel 108-. -From the panel 108 a control valve 109 is also controlled or actuated electrically and this valve corresponds to the valve 65 in the preceding embodiments and is intended for mechanically coupling together the tool carrier with the tool by means of the locking pins 12 movable to engage with the holding eyes 9 of the doubleacting hydraulic cylinder 16.

The operator actuates the control valve 109 from the control panel 108 to permit hydraulic oil to flow into the hydraulic cylinder 16 between its pistons. The pistons move the locking pins 12 to the locking position shown in figure 10 and bring about the mechanic coupling effect between the tool attachment and the tool. When the locking pins 12 have assumed this position, a transducer 110 connected to one locking pin is actuated and caused to emit a signal to the control panel 108, thereby notifying the operator that the mechanic coupling operation has taken place. It is thereafter possible for the operator to connect the hose couplings 104, 104a 105, 105a, by operating the control panel 108 and switching the control valves 107, 107a so as to allow the passage of hydraulic oil to the control devices 106, 106a respectively. Said devices thereby move together the respective hose couplings 104, 104a, 105, 105a. Hydraulic oil can flow to the working cylinders 100, 100a, from the hydraulic system 111 of the tool carrier via a control valve 112 in the tool carrier, the conduit 113, hose couplings 105, 105a and conduits 103, 103a and back to the hydraulic system 111 via the conduits 102, 102a, hose couplings 104, 104a a conduit 114 and the control valve 112.

For separating the tool from the tool carrier a fail-safe device should be provided and in such a manner, that the separation of the tool form the tractor, that is, the removal of the locking pins 12 from their locking positions can only take place once the hose couplings have been separated by the control devices 106, 106a.

In this embodiment, therefore the operator can decide when and which couplings are to be connected and which one or ones of the working cylinders are to be employed.

In figure 11 a further embodiment is shown, in which the connection of hose couplings 120, 121 is controlled by a control cam 122 on one of the piston rods 15 of the doubleacting hydraulic cylinder 16. When this piston rod is in its outer end position, the control cam 122 causes a check valve 123, to open so that hydraulic oil can flow to an overflow valve 124 provided with a check valve 125. The overflow valve then opens and permits hydraulic oil to pass to control devices 126 of the hose couplings 120, 121 and cause said devices to move together to effect hose coupling. In a return conduit 127 depending from the control devices 126 another valve 128 is provided which is similar to the valve 124 and is used when the hose couplings are to be disconnected.

WHAT WE CLAIM IS: 1. A coupling between a tool attachment adapted to be supported on a carrier and a tool mounting means adapted to carry a hydraulically operable tool, the coupling comprising mechanical locking means and hydraulic connecting means, the mechanical locking means comprising a fixed latch member attached to the tool mounting means, a movable latch member supported on the tool attachment and means for moving the movable latch member into engagement with the fixed latch member when the tool attachment and tool mounting means are in a coupling position, and the hydraulic connecting means comprising a pair of twopart hose couplings, one part of each pair being fixed on said tool mounting means and the other part of each pair being movably supported on said tool attachment, and means for moving said other part of each pair into hydraulic coupling with said one part, means being provided to allow coupling of the hydraulic connecting means only after coupling of mechanical locking means has been effected and to allow decoupling of the mechanical locking means only after decoupling of the hydraulic connecting means has been effected.

2. A coupling as claimed in claim 1 in which the movable latch member comprises a locking pin, the fixed latch member comprises an eye and said means for moving the movable latch member comprises a hydraulic cylinder and piston unit.

3. A coupling as claimed in claim 1 or 2 in which the means for moving said other part of the two-part hose couplings comprises an actuating member which is actuated against a returning force by said movable latch member once coupling of the mechanical locking means has been effected.

4. A coupling as claimed in claims 2 and 3 in which said actuating member comprises a guide pin which is disposed in axial alignment with said locking pin, which is actuated by said locking pin after said locking pin has engaged with said eye, and which is connected to said other part of each pair of the two-part hose couplings to move said other part into coupling engagement with said one part of each pair of the two-part hose couplings on further movement of the locking pin.

5. A coupling as claimed in claim 4 in which the actuating member further comprises a drawing bar attached at one end to said other part and at its other end, by way of an intermediate piece, to said guide pin, and in which said returning force is provided by a spring which engages with said drawing

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

control valve 109 is also controlled or actuated electrically and this valve corresponds to the valve 65 in the preceding embodiments and is intended for mechanically coupling together the tool carrier with the tool by means of the locking pins 12 movable to engage with the holding eyes 9 of the doubleacting hydraulic cylinder 16.

The operator actuates the control valve 109 from the control panel 108 to permit hydraulic oil to flow into the hydraulic cylinder 16 between its pistons. The pistons move the locking pins 12 to the locking position shown in figure 10 and bring about the mechanic coupling effect between the tool attachment and the tool. When the locking pins 12 have assumed this position, a transducer 110 connected to one locking pin is actuated and caused to emit a signal to the control panel 108, thereby notifying the operator that the mechanic coupling operation has taken place. It is thereafter possible for the operator to connect the hose couplings 104, 104a 105, 105a, by operating the control panel 108 and switching the control valves 107, 107a so as to allow the passage of hydraulic oil to the control devices 106, 106a respectively. Said devices thereby move together the respective hose couplings 104, 104a, 105, 105a. Hydraulic oil can flow to the working cylinders 100, 100a, from the hydraulic system 111 of the tool carrier via a control valve 112 in the tool carrier, the conduit 113, hose couplings 105, 105a and conduits 103, 103a and back to the hydraulic system 111 via the conduits 102, 102a, hose couplings 104, 104a a conduit 114 and the control valve 112.

For separating the tool from the tool carrier a fail-safe device should be provided and in such a manner, that the separation of the tool form the tractor, that is, the removal of the locking pins 12 from their locking positions can only take place once the hose couplings have been separated by the control devices 106, 106a.

In this embodiment, therefore the operator can decide when and which couplings are to be connected and which one or ones of the working cylinders are to be employed.

In figure 11 a further embodiment is shown, in which the connection of hose couplings 120, 121 is controlled by a control cam 122 on one of the piston rods 15 of the doubleacting hydraulic cylinder 16. When this piston rod is in its outer end position, the control cam 122 causes a check valve 123, to open so that hydraulic oil can flow to an overflow valve 124 provided with a check valve 125. The overflow valve then opens and permits hydraulic oil to pass to control devices 126 of the hose couplings 120, 121 and cause said devices to move together to effect hose coupling. In a return conduit

127 depending from the control devices 126 another valve 128 is provided which is similar to the valve 124 and is used when the hose couplings are to be disconnected.

WHAT WE CLAIM IS: 1. A coupling between a tool attachment adapted to be supported on a carrier and a tool mounting means adapted to carry a hydraulically operable tool, the coupling comprising mechanical locking means and hydraulic connecting means, the mechanical locking means comprising a fixed latch member attached to the tool mounting means, a movable latch member supported on the tool attachment and means for moving the movable latch member into engagement with the fixed latch member when the tool attachment and tool mounting means are in a coupling position, and the hydraulic connecting means comprising a pair of twopart hose couplings, one part of each pair being fixed on said tool mounting means and the other part of each pair being movably supported on said tool attachment, and means for moving said other part of each pair into hydraulic coupling with said one part, means being provided to allow coupling of the hydraulic connecting means only after coupling of mechanical locking means has been effected and to allow decoupling of the mechanical locking means only after decoupling of the hydraulic connecting means has been effected.
2. A coupling as claimed in claim 1 in which the movable latch member comprises a locking pin, the fixed latch member comprises an eye and said means for moving the movable latch member comprises a hydraulic cylinder and piston unit.
3. A coupling as claimed in claim 1 or 2 in which the means for moving said other part of the two-part hose couplings comprises an actuating member which is actuated against a returning force by said movable latch member once coupling of the mechanical locking means has been effected.
4. A coupling as claimed in claims 2 and 3 in which said actuating member comprises a guide pin which is disposed in axial alignment with said locking pin, which is actuated by said locking pin after said locking pin has engaged with said eye, and which is connected to said other part of each pair of the two-part hose couplings to move said other part into coupling engagement with said one part of each pair of the two-part hose couplings on further movement of the locking pin.
5. A coupling as claimed in claim 4 in which the actuating member further comprises a drawing bar attached at one end to said other part and at its other end, by way of an intermediate piece, to said guide pin, and in which said returning force is provided by a spring which engages with said drawing

bar and urges same in an uncoupling direction of said other part.
6. A coupling as claimed in claim 3 in which said actuating member comprises a pivotable arm which pivots in response to movement of said movable latch member and which actuates said other part of each pair of the two-part hose couplings on movement of said movable latch member.
7. A coupling as claimed in claim 6 in which said returning force in a spring which engages with said other part and urges same in an uncoupling direction of said other part.
8. A coupling as claimed in claim 1 in which said other part of each pair of the two-part hose couplings and said movable latch member comprise a single element.
9. A coupling as claimed in claim 8 in which said means for moving the movable latch member and the means for moving said other part comprise a hydraulic cylinder and piston unit.
10. A coupling as claimed in claims 8 and 9 in which said single element comprises a locking pin which is adapted to pass through an eye disposed on the tool mounting means to effect coupling of said mechanical locking means before engaging with said one part of each pair of the two-part hose couplings to effect coupling of said hydraulic connecting means.
11. A coupling as claimed in claim 10 in which the locking pin has a passage defined therethrough which leads to said other part disposed at the end of the locking pin and which opens at the other end of the locking pin at a flexible hose connection.
12. A coupling as claimed in claim 2 in which the piston, after moving the locking pin into locking engagement with the eye, actuates an overflow valve disposed in a hydraulic circuit to allow flow of hydraulic fluid into a cylinder and piston unit forming the means for moving said other part of each pair of the two-part hose couplings.
13. A coupling as claimed in claim 1 substantially as herein described with reference to figures 1 to 3 fig 4, figs 5 and 6 fig 7, fig 8, Fig 9, fig 10 or fig 11 of the accompanying drawings.