EP2690223B1 - Rapid action coupling for a works machine - Google Patents

Description

The present invention relates to a quick coupler for coupling a tool such as excavator buckets, claw grippers or demolition tongs to a tool guide such as excavator handle or the like, with a Ankuppelaufnahme for receiving a first locking member and a locking receptacle for receiving a second locking member, wherein the Ankuppelaufnahme a preferably self-locking securing element for Catching and / or securing the first locking part is assigned in the Ankuppelaufnahme and the locking receptacle is associated with a pressure-medium-actuated locking element for locking the second locking part in the locking receptacle.

A quick coupler according to the preamble of claim 1 shows the document EP 2 161 378 A1 This document proposes to provide a gravity-actuated latch that can block actuation of the second latch member. Other quick couplers are from the writings JP 2011/099239 A and US 2004/244575 A known.

On construction machines such as hydraulic excavators or articulated grapples such as wood handling machines or demolition equipment or similar material handling machines, quick couplers are often used to couple various tools such as tedding spoons, claw grabs or demolition tongs to a digger handle or similar tool guides such as articulated arm jibs to use various tools without long changeover times. Such quick couplers can in particular as locking elements two spaced apart locking axes on a coupling part, while the other coupling part, in particular the handlebar side coupling part may have a preferably hook-shaped coupling receptacle for hooking on a first of the two locking axes and a locking receptacle for locking on the second locking axis. After hooking the first locking axis in the Ankuppelaufnahme the two coupling parts can be pivoted to each other, wherein the seated in the Ankuppelaufnahme locking axis forms the axis of rotation, so that the second locking axis retracts into the locking receptacle or is pivoted into, where said second locking axis then by a locking element such as an extendable wedge can be locked, so that at the same time it is no longer possible to move the first locking axle from the Ankuppelaufnahme. The said locking axes on the one coupling part can thereby be formed by locking bolts, which may extend in particular parallel to each other on the corresponding coupling part, but instead of such bolts but possibly other structural parts of the coupling part such as projecting lugs, stub axles, engagement stumps in the form of projections or Recesses, for example in the form of pockets can serve as a locking part, which are adapted to the Ankuppelaufnahme or the locking receptacle of the other coupling part.

In order to prevent after hooking the said first locking axis in the Ankuppelaufnahme that the first locking axis dissolves again from the Ankuppelaufnahme in said pivoting action, has already been proposed to associate the Ankuppelaufnahme a securing element, for example in the form of a spring-loaded snap wedge, the hooking the locking axis in the hitch catch captures the locking axle and secures it in the hitch. When retracting the locking axle into the coupling seat, the safety catch is pushed back until the fully engaged position is reached, so that the safety catch can snap back again and block the extension path from the coupling seat. Around When dismantling a tool after unlocking the locking receptacle and the first locking axle from the Ankuppelaufnahme drive out or unhook, this fuse element must be released or spent in its releasing position. This can be done with fluid pressure, for example, by a single-acting pressure cylinder, which can drive the fuse element against its spring bias in the locking or blocking position back to the releasing position. As a result, a dismount of the machine operator or a manual actuation can be avoided.

In order to make the actual operating force transmitting locking mechanism by which the second locking element is fixed or locked in the locking receptacle, for example in the form of a locking axis, independent of the actuation of the securing element associated with the coupling receptacle, the unlocking or releasing of said Secured element on the Ankuppelaufnahme accomplished by a separate pressure medium circuit, which is independent of the pressure medium circuit for actuating the locking mechanism controllable or separately formed thereof. This decoupling is done to prevent interference on the fuse element can not affect the actual locking mechanism and can cause unintentional release of the coupler lock during operation. Such disturbances could be, for example, pressure losses on, for example, sealing elements which are provided in pressure circuit sections leading to the securing element of the coupling receptacle. Such a quick coupler with decoupled separate pressure circuits for the actuation of the locking mechanism and the unlocking of the securing element on the Ankuppelaufnahme shows, for example, the Scriptures EP 1852555 A2 ,

Since in practice in the past many times sold and still in use quick coupler of the type mentioned were not provided with such an additional securing element on Ankuppelaufnahme /, it would be desirable to provide such additional assurance on Ankuppelaufnahme not only for new equipment, ie to provide new quick couplers, but also to be able to retrofit to old quick couplers. The in the mentioned document EP 1852555 A2 Although shown solution is in principle also suitable for retrofitting already existing quick coupler, but requires three hydraulic connections, namely two connections for actuating the actual locking mechanism and a further pressure connection for unlocking the securing element of Ankuppelaufnahme due to the separate pressure circuit for actuating the securing element Ankuppelaufnahme. In many cases, however, only two hydraulic pressure connections are present on existing devices, so that the retrofitting with such additional assurance on Ankuppelaufnahme is often not possible.

On this basis, the present invention has the object to provide an improved quick coupler of the type mentioned, which avoids the disadvantages of the prior art and further develops the latter in an advantageous manner. In particular, an easy-to-operate additional assurance to Ankuppelaufnahme to be created, which does not require an increased number of pressure medium connections.

According to the invention, the stated object is achieved by a quick coupler according to claim 1. Preferred embodiments of the invention are the subject of the dependent claims.

It is therefore proposed to actuate the actual operating force transmitting locking device on the locking receptacle of the quick coupler and the additional assurance on Ankuppelaufnahme by a common pressure circuit and the common pressure circuit in such a way that the operation of the additional assurance of Ankuppelaufnahme and the operation of the locking mechanism takes place at the locking receptacle at different pressure levels, in particular such that the additional assurance of Ankuppelaufnahme can only be actuated and / or connected to the rest of the pressure circuit, if one for the actuation of the actual locking device sufficient or intended pressure is exceeded or such an excessive pressure is given to the leading to the additional assurance pressure circuit section. According to the invention the securing element of the Ankuppelaufnahme is also actuated by the pressure circuit which is provided for actuating the locking element of the locking receptacle, wherein said securing element via a pressure switching valve, which opens upon reaching / exceeding a predetermined first pressure, with the unlocking pressure port of Compression circuit is connected and the valve means of the pressure circuit comprises a pressure control means for controlling the voltage applied to the Entriegelungs-pressure port optionally to a second pressure greater than said first pressure and a third pressure less than said first pressure. By said pressure switching valve can be achieved that the additional assurance is connected to the coupling dome only to the pressure circuit for actuating the locking mechanism when the pressure circuit at the unlocking pressure port, the increased second pressure, which is above the switching pressure of the pressure switching valve provides. Meanwhile, the pressure circuit operates in its locking / unlocking mode for the locking element on the locking receptacle and provides at the unlocking pressure port and preferably also at the locking pressure port, a pressure level which is below the switching pressure of said pressure switching valve, the additional assurance on Ankuppelaufnahme remains uninvolved cut off by said pressure switching valve. Due to the connection of additional securing the Ankuppelaufnahme and locking mechanism of the locking receptacle to the common pressure circuit of the quick coupler comes out of spite despite additional assurance on Ankuppelaufnahme with only two pressure ports. Nevertheless, it is ensured by the intended operation at different pressure levels that the additional assurance on Ankuppelaufnahme not inadvertently opens before locking on the locking receptacle or damage to the additional assurance could lead to malfunction of the locking mechanism in working mode.

In a further development of the invention, the different levels of pressure for actuation of the securing element Ankuppelaufnahme on the one hand and the locking element of the locking receptacle on the other hand can be achieved by at least one pressure reducing valve, which can be bypassed by an upstream directional or switching valve either selectively or switched into the flow path, so that either a pressure reduced by the pressure reducing valve or a pressure not reduced by the pressure reducing valve can be given to the unlocking pressure port. As an alternative to such a bypass solution with a switching valve, it would also be possible to use a pressure-reducing valve that is variable or controllable with regard to pressure reduction, so that in this case a limit switching valve provided upstream of the pressure-reducing valve could possibly be dispensed with. However, said bypass solution with an upstream switching-off valve allows a reliable setting of two defined, sufficiently widely spaced pressure levels, by means of which in conjunction with the aforementioned pressure switching valve defined switching on or switching off the securing element of Ankuppelaufnahme can be achieved. In particular, the aforesaid pressure control means may comprise a pressure reducing valve which reduces the second pressure, which is above the switching pressure of the pressure switching valve and is provided for actuating the coupling member retaining element, to the third pressure smaller than the switching pressure of the pressure switching valve and for actuating the pressure switching valve Locking element of the locking receptacle is provided. The switching valve provided upstream of the pressure reducing valve may, in a first switching position, have an inlet pressure which may correspond to said second pressure and / or be provided from a pressure source to the pressure reducing valve and in a second switching position said inlet pressure past the pressure reducing valve to the unlocking Pressure connection gives. By "upstream" is meant that said switching valve is disposed between a pressure source or a pressure source port and the pressure reducing valve so that pressure coming from the pressure source or pressure fluid coming from the pressure source first flows through the switching valve before reaching the pressure reducing valve becomes.

In order to give the pressure reduced by the pressure reducing valve selectively to the unlocking pressure port or the locking pressure port, in the invention, the valve means on the output side of said pressure reducing valve comprise a directional or switching valve, in a first switching position from the Pressure Reducing Valve conducts reduced pressure to the interlocking pressure port and, in a second switching position, directs the pressure reduced by the pressure reducing valve to the unlocking pressure port. By switching over this switching valve optionally the unlocking or the locking side of the locking element of the locking receptacle associated Stellaktor can be pressurized, so that either the lock can be solved or closed.

In a further development of the invention, a further pressure reducing valve can be assigned to the locking pressure connection so that the pressure already reduced by the aforementioned first pressure reducing valve is reduced again and locking of the locking element of the locking receptacle takes place at a lower pressure than the unlocking. The pressure circuit can thus advantageously be designed such that the locking element is operated at locking on a different pressure level than when unlocking, advantageously the unlocking is accomplished with a higher pressure than the lock.

In order to prevent that when unlocking the locking element of the locking receptacle of the pressure reduction valve and the downstream switching valve on the unlocking pressure port given pressure on the pressure reduction valve upstream switching valve can flow unhindered back into the tank, in the invention between the switching valve, the the pressure reduction valve is connected upstream, and the unlocking pressure port to be provided a check valve, which may preferably be arranged between the two switching valves, which are arranged upstream of said pressure reduction valve and downstream. Alternatively or in addition to such a check valve and the pressure reducing valve upstream switching valve could be equipped with additional switching positions, for example, such that when switching the input pressure to the pressure reducing valve, the channel is locked to the unlocking pressure port.

In order to prevent further, when the full system pressure is applied to the unlocking line via the pressure reducing valve upstream switching valve to actuate the Stellaktors the fuse element, the pressure on the then open to the tank other switching valve, which is connected downstream of the pressure reducing valve to the tank escapes, in further development of the invention, a further check valve between the two switching valves - upstream or downstream of the pressure reducing valve - may be provided in the connected in this switching configuration with the tank line, which blocks the check valve to the tank.

In order to enable the securing element of Ankuppelaufnahme a provision in particular in the locking position and / or to allow a return flow of the pressurized fluid from the securing element of Ankuppelaufnahme after successful actuation, at least one relief line may be provided in the development of the invention past the pressure switching valve above, which preferably connects the Stellaktor said securing element on the pressure switching valve over with the locking pressure port and / or the unlocking pressure port of the pressure circuit. In order to prevent a too rapid outflow of the pressurized fluid and to ensure the actuation of the securing element with the pressure switching valve open, a flow obstructer may preferably be provided in the said recirculation or relief line in the form of an orifice. By the relatively high pressure level in the operation of the fuse element is thereby ensured that the securing element driving actuator is actually actuated, while on the other hand with closed pressure switching valve, if perhaps slow, backflow or pressure relief over said aperture is possible away.

Conversely, to prevent accidental actuation of the fuse element via the said discharge or return line, the Stellaktor of the fuse element can be connected via two discharge lines with both the locking pressure port and with the unlocking pressure port respectively connected to said pressure switching valve in the invention be, in which case each of the discharge lines can be traversed by a check valve only in relief direction. By the parallel connection of the two check valves and the corresponding discharge lines not only the return of the pressure fluid can be accomplished by the Stellaktor of the fuse element, but it prevents the same time that comes with a defective check valve pressure from the locking or unlocking line forth on the Stellaktor of the fuse element, Since such a pressure can pass though the defective check valve, but can be derived directly via the second check valve connected in parallel, since in this case the said second check valve is connected to the tank via the then pressure-relieved unlocking or locking line.

Fig. 1:

eine schematische Seitenansicht eines Schnellkupplers nach einer vorteilhaften Ausführung der Erfindung, der an einen Auslegerstiel eines Baggers angebaut ist und als Anbauwerkzeug einen Grablöffel ankuppelt,

Fig. 2:

eine perspektivische Darstellung des Schnellkupplers aus Fig. 1 in einer abgekuppelten Stellung, in der die beiden miteinander kuppelbaren Kupplungsteile kurz vor dem Einhaken am Hakenabschnitt gezeigt sind,

Fig. 3:

eine Schnittansicht durch den Kupplungsteil des Schnellkupplers aus den vorhergehenden Figuren, der die Ankuppelaufnahme und die Verriegelungsaufnahme sowie die zugehörigen Sicherungs- und Verriegelungselemente und deren Stellaktoren zeigt, und

Fig. 4:

einen Schaltplan des gemeinsamen Druckkreises zur Betätigung des der Ankuppelaufnahme zugeordneten Sicherungselements und des der Verriegelungsaufnahme zugeordneten Verriegelungselements.

The invention will be explained in more detail below with reference to a preferred embodiment and associated drawings. In the drawings show:

Fig. 1:

a schematic side view of a quick coupler according to an advantageous embodiment of the invention, which is grown on a boom arm of an excavator and attaches a grapple as an attachment tool,

Fig. 2:

a perspective view of the quick coupler Fig. 1 in a decoupled position, in which the two coupling parts which can be coupled with one another are shown shortly before hooking on the hook section,

3:

a sectional view through the coupling part of the quick coupler from the preceding figures, the Ankuppelaufnahme and the locking receptacle and the associated securing and locking elements and their Stellaktoren shows, and

4:

a circuit diagram of the common pressure circuit for actuating the Ankuppelaufnahme associated securing element and the locking receptacle associated locking element.

As Fig. 1 shows, the quick coupler 1 between the free end of the boom 5 of an excavator 30 and the tool to be mounted on it 4 are mounted, said attachment tool 4 in Fig. 1 is designed as a grave spoon, but in a conventional manner, of course, other corresponding construction, handling or demolition tools, for example in the form of clamshell, demolition tongs, scissors or the like may include. Said quick coupler 1 is in this case on the one hand by means of a handle-side coupler part 2 pivotally mounted to a lying, aligned transversely to the longitudinal axis of the boom stem 5 pivot axis of said boom arm 5, so that the quick coupler 1 together with the attached tool 4, for example by means of a pressure medium cylinder 36 and an intermediate swivel piece 7 can be pivoted relative to the boom stem 5.

By means of a tool-side coupler part 3 - see. Fig. 2 On the other hand, said quick coupler can be mounted on the attachment tool 4 and / or an intermediate rotary drive.

As the FIGS. 2 and 3 show, one of the two coupler parts 2 and 3, preferably the handle-side coupler part 2 on the one hand a Ankuppelaufnahme 6 and on the other hand comprise a locking receptacle 10 which hooks with two locking parts, for example in the form of locking axes 13 and 14 on the other, preferably tool-side coupler part 3 can be brought into engagement. Contrary to the illustration of the drawing, it would also be possible in principle, on a coupler part a locking axis and a receptacle and the other coupler part in turn a locking axis and a However, the embodiment shown with two receptacles, ie locking receptacle and Ankuppelaufnahme on one coupler part and two corresponding locking axes on the other coupler part is preferred because the associated locking and locking elements and their operation can then be summarized on a coupler part.

As Fig. 2 shows the Ankuppelaufnahme 6 and the locking receptacle 10 each have a mouth-shaped, open to one side receptacle into which the locking axles 13 and 14 can retract, which may be formed by transverse bolts or locking bolts, see. Fig. 2 , The Ankuppelaufnahme 6 and the locking receptacle 10 are advantageously arranged and configured such that when a first locking axle 13 of a coupler part 3 is retracted or hooked into the preferably hook-shaped Ankuppelaufnahme 6 of the other coupler part 2, the two coupler parts can be pivoted to each other in such a way that the Ankuppelaufnahme 6 and the locking shaft 13 received therein form the axis of rotation and can retract the second locking shaft 14 in the locking receptacle 10 by the corresponding pivoting movement, so that the two coupler parts 2 and 3 are coupled together in a two-stage coupling process can. First, the Ankuppelaufnahme 6 is hooked to the first locking shaft 13 to then by pivoting the two coupler parts 2 and 3 relative to each other - which can be done for example by actuation of the aforementioned pivoting cylinder 36 - the locking receptacle 10 can be brought into engagement with the second locking axis 14.

If the second locking axle 14 is retracted into the locking receptacle 10, said second locking axle 14 is locked in the locking receptacle 10 or the locking receptacle 10 is closed, so that the second locking axle 14 can not come out. For this purpose, a locking element 11 is provided, for example in the form of a locking wedge, which can be moved on the opening side of the locking receptacle 10 in front of the locking shaft 14 received therein, cf. Fig. 3 , For the operation of said Locking element 11 is hereby advantageously a hydraulically actuated Stellaktor 12 is provided which is directly or indirectly connected to said locking element 11 and advantageously double-acting, so that it can be moved back and forth.

By locking the locking element 11 not only the second locking shaft 14 is held in the locking receptacle 10, but also the two coupler parts 2 and 3 locked together because the Ankuppelaufnahme 6 is formed so that the first locking axle 13 received therein not from the Ankuppelaufnahme. 6 out, when the second locking shaft 14 is caught in the locking receptacle 10.

Nevertheless, the said Ankuppelaufnahme 6 is associated with a securing element 7, by means of which the first locking shaft 13 and a suitable locking part can be caught in the Ankuppelaufnahme 6 or can be secured or blocked, so that the first locking shaft 13 is not from the Ankuppelaufnahme 6 accidentally slip out. This fuse element 7 is mainly used during the aforementioned pivotal movement during the coupling process to prevent accidental slipping out of the first locking shaft 13 from the Ankuppelaufnahme 6, as long as the two coupler parts 2 and 3 are not yet locked together by closing said locking element 11.

Said securing element 7 can likewise be a wedge-shaped slide or else Fig. 3 shows, be a pivotally mounted locking lever, which tapers in its locking position, the opening of the Ankuppelaufnahme 6 so far or blocked that the first locking shaft 13 can not slip out, see. Fig. 3 , Said securing element 7 is in this case advantageously designed as a self-locking snapper, which is biased by a biasing device, in particular in the form of a spring 9 in the locking position, however, can be automatically pushed back when retracting the first locking shaft 13 in the Ankuppelaufnahme 6. If the locking axis 13 is complete or retracted sufficiently far into the Ankuppelaufnahme 6, the fuse element 7 driven by the spring 9 can snap back into the locking position, so that the locking shaft 13 is caught.

To release the securing element 7 for the purpose of uncoupling the said securing element 7 is associated with a Stellaktor 8 in the form of a single-acting hydraulic cylinder, by means of which the securing element 7 can be moved or pivoted into its releasing position.

The control of the two mentioned locking and locking elements 7 and 11 by a common pressure circuit 15 shows Fig. 4 , The pressure circuit 15 is in this case on the one hand connected to a pressure source P, for example in the form of a pump, by means of which the pressure circuit 15 is supplied with pressure fluid, in particular hydraulic pressure, and on the other hand connected to a tank T, can flow back into the pressurized fluid. On the other hand, the pressure circuit 15 comprises two pressure ports, namely on the one hand a locking pressure port 17 and on the other hand, an unlocking pressure port 16 to which the double-acting actuator 12 of the locking element 11 is connected to release the lock of the quick coupler 1 and close, ie the Lock second locking axle 14 in the locking receptacle 10 and unlock. In order to be able to control this main locking process or unlocking process, the pressure circuit 15 comprises a valve device 18, by means of which either the unlocking pressure connection 16 or the locking pressure connection 17 can be connected to the pressure source P.

As Fig. 4 shows, the valve means 18 for this purpose comprises a primary switching valve 23 which switches in a switching position coming from the pressure source P forth pressure line on the locking pressure port 17 and the unlocking pressure port 16 to the tank and reversed in another switching position reversed from the Pressure source P forth coming line with the unlocking pressure port 16 and the locking pressure port 17 connects to the tank. In the leading to the locking pressure port 17 line is doing a pressure reducing valve 28 is provided so that the pressure used for locking is lower than the pressure used for unlocking. As Fig. 4 shows, the said pressure reducing valve 28 is advantageously provided with a bypass 31 which is connected to a check valve 32 in order to avoid the resistance of the pressure reducing valve 28 when unlocking.

The provided for actuating the securing element 7 Stellaktor 8 is connected via a pressure switching valve 19 to the unlocking pressure port 16, said pressure switching valve 19 is designed such that the securing element 7 is shut off at the intended for unlocking the locking element 11 pressure from the rest of the pressure circuit , ie the pressure switching valve 19 opens only at a pressure p1, which is above the normal unlocking pressure for unlocking the locking element 11. In order to adjust the different pressure levels for the actuation of the locking element 11 on the one hand and the actuation of the securing element 7 on the other hand, the valve device 18 comprises a corresponding pressure control device 20, according to the drawn embodiment according to Fig. 4 a pressure reducing valve 21 and a pressure reducing valve 21 upstream of the switching or switching valve or secondary switching valve 22 may include. Said pressure reducing valve 21 and the secondary switching valve 22 upstream therefrom are advantageously preceded by the primary switching valve 23 described above, so that pressure coming from the pressure source P first reaches the secondary switching valve 22 and then the pressure reducing valve 21 before the first from the pressure reducing valve 21 reduced pressure then passes to the primary switching valve 23.

At the in Fig. 4 shown switching position of the secondary switching valve 22, the coming of the pressure source P forth input pressure p2 is switched to said pressure reducing valve 21 to be reduced and then used by the primary switching valve 23 either for unlocking or locking the locking element 11. The reduced by said pressure reducing valve 21 pressure p3 is smaller than the switching pressure of the pressure switching valve 19, so that the fuse element 7 from the pressure circuit 15 and its pressure leading Section remains locked. If, however, the secondary switching valve 22 is moved to its other switching position, the pressure reducing valve 21 is bypassed and given the full inlet pressure p2 from the pressure source P forth on the unlocking pressure port 16. The pressure switching valve 19 is designed and adjusted such that the switching pressure is smaller than said input pressure p2, so that in this case, the pressure switching valve 19 opens and the pressure on the fuse element 7 and its Stellaktor 8 is given, whereby the Ankuppelaufnahme. 6 is unlocked.

As Fig. 4 shows, in the main control block of the valve device 18, a check valve 24 is provided, which is provided between the secondary switching valve 22 and the unlocking pressure port 16 in the bypass line to the pressure reducing valve 21 around. This check valve 24 prevents upon actuation of the primary switching valve 23 for unlocking the locking receptacle 10 an unwanted pressure loss on the still un-actuated secondary switching valve 22 toward the tank T.

Another check valve is provided in the other connection line between the secondary switching valve 22 and the primary switching valve 23 to prevent the switching state for unlocking the securing element 7, ie for actuating the actuator 8, the pressure given to the unlocking pressure port 16 unintentionally flows back over the then open to the tank primary switching valve 23. In this configuration, the full system pressure p2 is passed over the then switched on switching valve 22 on the pressure reducing valve 21 on said unlocking pressure port 16, while on the other hand, the primary switching valve 23 is switched to the unlocked position, so that the fully switched system pressure p2, so to speak backwards over the primary switching valve 23 and the pressure reducing valve 21 could flow to the tank, but this is prevented by the check valve 40. Said check valve 40 may in this case be provided upstream or downstream of said pressure reducing valve 21 between the two switching valves 23 and 22.

As Fig. 4 further shows, further check valves 25 and 26 are provided in relief lines that connect the Stellaktor 8 of the fuse element 7, bypassing the aforementioned pressure switching valve 19 with the unlocking pressure port 16 and the locking pressure port 17 and thus depending on the switching position of the main valve block with the tank, to allow a reflux of the pressed into the Stellaktor 8 fluid. As Fig. 4 shows, the said relief lines 33 and 34 are connected to a respective check valve 25 and 26, which check valves allow only a backflow of hydraulic fluid, but no actuation of the Stellaktors 8 forth from the pressurized pressure ports ago.

In principle, instead of the two relief lines 33 and 34, only such a relief line could be provided in order to allow a reflux of the fluid pressed into the adjusting actuator 8. However, the use of two such relief lines 33 and 34 together with the non-return valves 25 and 26 provided therein, in particular with parallel arrangement of the two check valves, but increases the security against accidental opening of the fuse element 7 in case of failure of one of the two check valves 25 and 26 Should one of Check valves 25 or 26 have a malfunction and let fluid pressure toward the Stellaktor 8 of the fuse element 7, so this pressure is always reduced immediately via the second check valve, since the other line to which said other, second check valve is connected, ie the Line or port 16 or 17 is necessarily connected to the tank T. If pressure is applied to one non-return valve from one of the ports 16 or 17, the respective other port 17 or 16 is depressurized and connected to the tank, so that the in Fig. 4 shown parallel connection of two check valves on the return flow side of the Stellaktors 8 significantly increased the security against its incorrect operation.

In order to prevent too fast backflow of the pressurized fluid through said discharge lines 33 and 34, in particular when the pressure switching valve 19 is open, said relief lines 33 and 34 are provided with a flow obstruction 27 in the form of a diaphragm, see. Fig. 4 ,

The leading to the lock line relief line 33 here allows the relaxation of the hydraulic pressure in Stellaktor 8 of the fuse element 7, as soon as the secondary switching valve 22 is brought back into the starting position and thus the safety device of Ankuppelaufnahme 6 should be activated again, i. should be reset by the spring 9 again. This will, so to speak, lock in the pressure at that location, i. prevents the area of Stellaktors 8 when the pressure switching valve 19 closes due to falling below the switching pressure in the unlocking again. In addition, in this case, the switching pressure in the unlocking line or the unlocking pressure connection 16 is still initially present, so that it would not be possible to relieve this pressure without closing the pressure switching valve 19 in this way. In this case, however, the pressure above the lock-pressure port 17 and the still-actuated primary switching valve 23 can be reduced to the tank T.

The other discharge line 34, which goes from said aperture to the unlocking line or the unlocking pressure port 16, allows a pressure reduction when the primary switching valve 23 against a scheduled normal operation at the same time or very shortly after the secondary switching valve 22 back into the in Fig. 4 shown initial position is brought, for example, by incorrect operation or power failure. The pressure on the Stellaktor 8 of the securing element 7 can then be reduced to the tank T via the then open unlocking line or the still open unlocking pressure port 16 and the primary switching valve, cf. Fig. 4 ,

Claims (12)

1. A quick coupler for coupling a tool (4) to an excavator arm (5) or the like, comprising a coupling receptacle (6) for receiving a first locking part (13) and a locking receptacle (10) for receiving a second locking part (14), wherein to the coupling receptacle (6) a preferably self-locking securing element (7) is associated for catching and/or securing the first locking part (13) in the coupling receptacle (6), and to the locking receptacle (10) a pressure-medium-actuatable locking element (11) is associated for locking the second locking part (14) in the locking receptacle (10), wherein the locking element (11) is actuatable by a pressure circuit (15) which includes an unlocking pressure port (16) and a locking pressure port (17), which via a valve means (18) are selectively connectable with a pressure source (P) or a return line (T), wherein the securing element (7) of the coupling receptacle (6) likewise is actuatable by said pressure circuit (15), characterized in that the securing element (7) is connected with the unlocking pressure port (16) via a pressure switching valve (19), which opens upon reaching/exceeding a predetermined first pressure (p1), and the valve means (18) of the pressure circuit (15) includes a pressure control means (20) for selectively controlling the pressure applied at the unlocking pressure port (16) to a second pressure (p2) greater than the first pressure (p1) and to a third pressure (p3) smaller than said first pressure (p1), wherein the pressure control means (20) is formed such, that the actuation of the securing element (7) of the coupling receptacle (6) is effected at a higher pressure level than the actuation of the locking element (11) of the locking receptacle (10).
2. Quick coupler according to the preceding claim, wherein the portion of the pressure circuit (15) leading to the securing element (7) is shut off from the rest of the pressure circuit (15) upon actuation of the locking element (11) with the intended lower pressure level.
3. The quick coupler according to the preceding claim, wherein said pressure control means (20) includes a pressure reducing valve (21) for reducing the second pressure (p2) to the third pressure (p3) and a switching valve (22) provided upstream of the pressure reducing valve (21), which switching valve (22) in a first switching position applies an input pressure (p2) to the pressure reducing valve (21) and in a second switching position applies said input pressure (p2) past the pressure reducing valve (21) to the unlocking pressure port (16).
4. The quick coupler according to the preceding claim, wherein the valve means (18) downstream of the pressure reducing valve (21) includes a further switching valve (23), which switching valve (23) in a first switching position passes the pressure (p3) reduced by the pressure reducing valve (21) to the locking pressure port (17) and in a second switching position passes the pressure reduced by the pressure reducing valve (21) to the unlocking pressure port (16).
5. The quick coupler according to the preceding claim, wherein the switching valve (22) provided upstream of the pressure reducing valve (21) is connected with the unlocking pressure port (16) via a check valve (24) which prevents a back flow from the unlocking pressure port (16), wherein said check valve (24) preferably is provided in the bypass line around the pressure reducing valve (21) between the switching valve (22) provided upstream of the pressure reducing valve (21) and the switching valve (23) provided downstream of said pressure reducing valve (21).
6. The quick coupler according to any of the two preceding claims, wherein between the two switching valves (22, 23) which are provided upstream and downstream of the pressure reducing valve (21) a check valve (40) is provided in the line pressurized for locking and unlocking the locking element (11), which prevents a back flow towards the switching valve (22).
7. The quick coupler according to any of the preceding claims, wherein the securing element (7) is connected with the unlocking pressure port (16) and/or the locking pressure port (17) past the pressure switching valve (19) via at least one check valve (25, 26), wherein the at least one check valve (25, 26) prevents a fluid flow from the unlocking pressure port (16) and/or the locking pressure port (17) towards the securing element (7) and/or permits only a back flow from the securing element (7) towards the unlocking pressure port (16) and/or the locking pressure port (17).
8. The quick coupler according to the preceding claim, wherein between the at least one check valve (25, 26) and the securing element (7) a flow impeder preferably in the form of an orifice plate (27) is provided.
9. The quick coupler according to any of the two preceding claims, wherein past the pressure switching valve (19) two return lines (33, 34) connected in parallel with one check valve (25, 26) each are provided, of which return lines one (33) is connected with the locking pressure port (17) and the other one (34) is connected with the unlocking pressure port (16).
10. The quick coupler according to any of the preceding claims, wherein the valve means (18) includes a pressure reducing valve (28) associated to the locking pressure port (17) for reducing the pressure provided for locking the locking element (11) to a pressure (p4) smaller than the pressure (p3) provided for unlocking the locking element (11).
11. The quick coupler according to any of the preceding claims, wherein between the locking pressure port (17) and the locking element (11) a check valve (29) preventing the back flow from the locking element (11) to the locking pressure port (17) is provided, which can be unlocked by the pressure (p3) provided at the unlocking pressure port (16) for unlocking the locking element (11).
12. The quick coupler according to any of the preceding claims, wherein the securing element (7) of the coupling receptacle (6) is biased into a locking position by a biasing device, in particular a spring means (9), and can be unlocked against the bias by a single-acting pressure medium cylinder (8), which is connected with the unlocking pressure port (16), and/or wherein a double-acting pressure medium cylinder (12) is associated to the locking element (11), which on the one hand is connected with the unlocking pressure port (16) and on the other hand with the locking pressure port (17).

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