Quick changer The invention relates to a quick changer according to the preamble of claim 1.
Such quick changers are used for easy and convenient changing of different attach- ments on construction machines.
With such a quick changer, e.g. swing buckets, grabs, shears, compactors, magnets, hydraulic hammers or other attachments can be coupled or uncoupled, e.g. on a boom of an excavator, from an operator's cab in a few seconds and with high safety standards.
A generic quick changer is known from CH 700 307 A1. This known quick changer is provided with, on one side of a support, a fixed first gripper with an insertion opening for receiving a first retaining pin and, on the other side of the support, a second gripper with an insertion opening for receiving a second retaining pin, the — second gripper being movable by means of an actuator between a release position and a locking position.
A mechanical locking member in the form of two rods ex- tending parallel to the piston rod in the direction of the insertion openings is at- tached to the second gripper, which is connected to a piston rod of the actuator.
First ends of the rods are screwed to the movable second gripper, while second — ends of the rods arranged in the area of the insertion opening of the fixed first gripper have a bend.
By displacing the gripper, the rods are movable between an extended pick-up position and a retracted closing position.
In the retracted locking position, the curvatures at the end of the rods align with the retaining pin so that, even if the grippers break, the retaining pin will wedge between the insertion open- ing and the rods, thus preventing the quick changer and attachment from separation due to material failure.
However, the locking device formed by the two rods must be activated by an operator through respective actuation of the actuator.
A quick changer disclosed in WO 2004/038110 A1 comprises a support having on one side a C-shaped first receiver for receiving a first bolt-shaped coupling ele- ment, and on the other side a second receiver with a hook-shaped locking element displaceable by means of a cylinder for receiving a second bolt-shaped coupling element.
A locking pin is inserted into a bore in a horizontal lower part of the C- shaped first receiver designed as a bent part.
However, such a locking pin does not constitute a catch hook and does not serve to catch an attachment part in motion, but only serves to securely hold the first bolt-shaped coupling element within the C-shaped first receiver.
Moreover, the locking pin must manually be inserted by the operator after proper coupling and be secured by an additional spring locking splint pin.
Here too, an active intervention by the operator is required to activate the securing device.
A quick changer known from US 2012/0093572 A1 comprises, on one side of a support, first claw-shaped receivers for receiving a first coupling element and, on the other side of the support, second claw-shaped receivers with a hook-shaped locking element that can be pivoted about a transverse axis.
An additional hook- — shaped locking element is provided on the first claw-shaped receivers.
The two hook-shaped locking elements are coupled to each other via a leverage in such a way that they are actuated together via a piston drive.
Here too, an active interven- tion of the operator with an actuation of the piston drive is required to activate the locking elements.
If the first locking element is inadvertently moved into the open — position, the second locking element is also forcibly moved into the open position.
Also in a quick changer known from EP 2 119 834 A2, on one side of a support, first claw-shaped receivers for receiving a first coupling element are provided and, on the other side of the support, second claw-shaped receivers for receiving a sec- — ond coupling element are provided.
A hook-shaped first locking element that can be pivoted about a transverse axis and that can be moved between an open position and a closed position by means of a piston drive is arranged on the first receivers.
A cam-shaped second locking element is provided on the second receivers.
The cam-shaped second locking element is coupled with the first locking element in — such a way that they are actuated simultaneously by respective actuation of the piston drive.
Another quick changer is known from US 6 154 989 A.
This contains a support which has, on one side, first receivers for holding a first coupling element provided on an attachment and, on the other side, second receivers with a locking element movable between a release position and a locking position for releasably holding a second coupling element.
In order to prevent the attachments from falling and thus from possibly endangering persons in the event of an unintentional movement of the locking element into a release position, a catch device with a hook arrange- ment for holding a transverse bar cooperating with counter hooks on the attachment is provided on the support.
Since the hook arrangement provided for securing is made in one piece with the support, damage to the hook arrangement caused by improper use will always also affect the entire support.
Thus, a repair or replace- ment is associated with considerable expense.
It is an object of the invention to obtain a quick changer of the type mentioned at — the beginning, which contains a safety device that is easy to mount and, if neces- sary, easy to replace.
This object is solved by a guick changer with the features of claim 1. Practical embodiments and advantageous further developments of the invention are indi- cated in the subclaims.
In the quick changer according to the invention, the catch device has at least one catch hook which is connected to the support via a non-destructively releasable connection in a firmly and non-pivotably manner and which is designed for catch- ing an attachment for additional safety independently of the operator.
A catch hook damaged by improper use thus can be easily replaced without having to replace the entire support.
There is no need to dismantle or replace the entire support.
The cut point or separation point between the support and the catch hook can also ensure that damage to the support in the event of improper loads on the catch hook assem- bly is avoided.
For example, if a catch hook is used in an unauthorised manner to support an excavator for turning or repositioning on the ground, this is more likely to cause the connection between the support and the catch hook to become loose or to damage the easily replaceable catch hook, whereas the support is affected as little as possible. The at least one catch hook is designed to catch an attachment coupled to the quick changer even in the event of an unintended release movement of a locking device, thus preventing unwanted disconnection of the attachment from the quick changer. The catch hook is completely independent of the quick changer's locking device, which is controlled by the operator, and thus offers in- creased safety even in the event of improper operation. The catch device may comprise one or more separate or interconnected catch hooks. In a particularly practical embodiment, the catch device can be formed by two catch hooks arranged on the first receivers of the support. In a robust and constructively advantageous embodiment, the non-destructively releasable connection can be formed by at least one connecting element and asso- ciated receivers in the support and the catch hook. For example, the connecting elements can be designed as connecting bolts and the receivers can be designed as bores. The connecting bolt can be designed as a screw or pin. The non-destructible connection can also be designed as a tongue and groove joint or in another suitable way. In a particularly advantageous design for the introduction of force, the bores for the at least one connecting pin can be arranged in a connecting bar projecting from the support and on a connecting groove on the catch hook corresponding to the connecting bar. A particularly practical interface between the support and the catch hook can be obtained due to the connecting bar on the support having a trapezoidal cross-section with oppositely inclined outer contact surfaces and the connecting groove on the catch hook containing a corresponding trapezoidal cross-section with oppositely inclined inner contact surfaces. — A particularly good protection of the support in case of inadmissible loads on the catch hook can be obtained by the distance between a front edge of the catch hook and the bore in the catch hook being smaller than the distance from a front edge of the connecting bar to the bore in the connecting bar.
In this way, the loads are more likely to be transferred to the catch hook.
However, the connecting bar on the support can also protrude between two limbs 5 of a catch hook being spaced apart from each other.
According to a further advantageous design, the catch hook can be made of a softer or more flexible material than the support.
This can additionally ensure that, in the event of improper loading, the catch hook is deformed or damaged even before the — support is.
For example, the support can be made of a tougher or more wear-re- sistant material than the catch hook.
In a structurally simple embodiment, the catch hook is designed for gripping around a coupling element that engages with the first receivers.
Further features and advantages of the invention will be apparent from the follow- ing description of a preferred example of an embodiment based on the drawing.
It is shown: Figure 1 a perspective view of a quick changer with a catch hook arrange- ment; Figure 2 an enlarged detailed view A of figure 1; Figure 3 a perspective view of the quick changer of figure 1 without the catch hook arrangement; Figure 4 an enlarged detailed view B of figure 3; Figure 5 a side view of the quick changer of figure 1; Figure 6 an enlarged detailed view C of figure 5;
Figure 7 a cross-section of the separation point between a catch hook and the support when loaded from below; Figure 8 a cross-section of the separation point between a catch hook and the support when loaded from above; Figure 9 a quick changer with a second embodiment of a catch hook arrange- ment in a disassembled state;
Figure 10 a catch hook of the embodiment of figure 9, and Figure 11 the quick changer of figure 9 with the second embodiment of a catch hook arrangement in the assembled state.
Figure 1 shows a quick changer 1 for easy and convenient changing of different attachments on construction machines, especially excavators.
With such a quick changer, e.g. buckets, grabs, shears, magnets, compactors, hydraulic hammers or other mechanical or hydraulic attachments can be easily and conveniently coupled or uncoupled to or from a boom or another attachment part of an excavator or of another construction vehicle from the driver's cab.
The quick changer 1 shown contains a support 2 designed as a welded or cast part, which contains, on one side, first receivers 3 open towards the front for receiving and holding a first bolt-shaped coupling element and, on the other side, second receivers 4 open towards the bottom for receiving a second bolt-shaped coupling element.
The first receivers 3 open towards the front are designed in the shape of a claw or fork.
The receivers 4 open towards the bottom have a curved lower con- tact surface 5 for contact with the second bolt-shaped coupling element.
The sup- — port 2 contains guide bores 6, shown in Figure 1, in which a piston-shaped locking element 7, shown in Figure 5, is slidably guided and arranged so that it can be moved hydraulically between a retracted release position and an extended locking position shown in Figure 5. In the extended locking position, the second receivers 3 open towards the bottom are closed at the bottom by the locking element 7 ar- ranged in the guide bores 6, so that the second bolt-shaped coupling element is engaged underneath by the locking element 7. Thus, a locking device for releasably holding an attachment on the quick changer 1 is obtained.
In the embodiment shown, the support 2 contains, on one side, two claw-shaped first receivers 3 for a first coupling element and, on the other side, two receivers 4 for a second coupling element.
Moreover, on two parallel side parts 8 arranged on the upper side of the support 2, continuous receiving openings 9 for fastening bolts, not shown, for fastening the quick changer 1 to a boom of an excavator or to a connecting part of another construction vehicle are provided.
In order to couple an attachment with the aid of the quick changer 1, the quick changer 1, which is usually arranged on a boom of an excavator, initially is moved in such a way that a first coupling element 5 arranged, for example, on an adapter or on the attachment is retracted into the claw-shaped receivers 3 on the one side of the quick changer 1. Then, with the locking elements 7 still retracted, the quick changer 1 is pivoted around the first bolt-shaped coupling element 5 in such a way that a second coupling element on the adapter or attachment comes into contact with the contact surfaces 5 of the downwardly open receivers 4 on the other side of the quick changer 1. Subsequently, the bolt-shaped locking elements 7, which are displaceably arranged in the guide bores 6 in the support 2 of the quick changer 1, can be extended hydraulically so that the second bolt-shaped coupling element is engaged underneath by the two locking elements on the quick changer 2 and thus the attachment is held on the quick changer 1. In order to prevent an attachment coupled to the quick changer 1 from unintention- ally disengaging from the quick changer in the event of an unintentional disengag- ing movement of the locking element 7 due to incorrect operation or malfunctions and then from possibly falling down in a raised position of the quick changer, an additional catch device 10 shown in Figure 1 is provided on the support 2. The catch device 10 is designed to grip around the coupling element which is arranged on an adapter or attachment and which is engaging with the first receivers 3. The catch device 10 is designed in such a way that an attachment is caught in a catch position by engagement of the coupling element on the catch hook arrangement in the event of unintentional release from the coupling position and is thereby held on the quick changer.
In the embodiment shown, the catch device 10 comprises two separate catch hooks 11 which are connected to the support 2 by means of a non-destructively releasable screw or pin connection.
For this purpose, the support 2 as shown in Figure 2 has forwardly projecting connecting bars 12 for engagement in corresponding connect- ing grooves 13 of the catch hooks 11. As can be seen from Figures 3 and 4, the connecting bar 12 has a trapezoidal cross-section with oppositely inclined outer contact surfaces 14. The connecting groove 13 in the catch hooks 11 is designed as a keyway with a trapezoidal cross-section.
Figure 6 shows that the connecting groove 13 contains two oppositely inclined inner contact surfaces 15. On the catch hooks 11 and in the connecting bars 12, receivers 16 and 17, respectively, are pro- vided in the form of bores for receiving bolt-shaped connecting elements 18. In the embodiment shown, the bolt-shaped connecting elements 18 are designed as threaded bolts.
However, the connecting bolts 18 can also be designed as pins.
Figures 7 and 8 show cross-sections of the separation point between the connecting bar 12 of the support 2 and a catch hook 11 without the bolt-shaped connecting element 18 when the catch hook 11 is loaded from below and above.
It can be seen from these illustrations that the catch hook 11 is "rotated out" from the connecting bar 12 in both loading cases, thereby stressing the bolt-shaped con- necting element 18, which is not shown, to shear.
For example, if an excavator supports itself on the ground via the catch hook 11 and the catch hook 11 is thereby subjected to a force in the direction of arrow U of Figure 7, the main loads are in area A on the underside of the catch hook 11 and in area B of the connecting bar 12. To ensure that area A of the catch hook 11 is more likely to be damaged by said load, the distance X from a front edge 19 of the catch hook 11 to the receiver 16 in the catch hook, which is in the form of a bore, is smaller than the distance Y from a front edge 20 of the connecting bar 12 to the receiver 17 in the connecting bar 12, which is in the form of a bore.
On the other hand, if, due to an incorrect load from above, the catch hook 11 is subjected to a force in the direction of the arrow O in Figure 8, the areas B of the connecting bar 12 and the area C on the upper side of the catch hook 11 are sub- jected to a greater load.
Since the distance W between the front edge 19 of the catch hook 11 and the receiver 16 in the catch hook 11, which is in the form of a bore, is smaller than the distance Y from the front edge 20 of the connecting bar 12 to the receiver 17 in the connecting bar 12, which is in the form of a bore, any damage is more likely to occur on the catch hook 11 than on the connecting bar 12 of the support 2. Furthermore, the catch hook 11 is designed in such a way that the area C of the catch hook 11 lying above the connecting groove 13 between the front edge 19 and the receiver 16, which is in the form of a bore, has a larger cross-section than the area A lying below the connecting groove 13 between the front edge 19 and the receiver 16, which is in the form of a bore.
Figures 9 to 11 show another quick changer 1 with a catch device 10 according to a second embodiment.
In this embodiment, too, the catch device 10 comprises two — separate catch hooks 11, which are connected firmly to the support 2 via a non- destructively releasable pin connection.
As shown in Figure 9, the support 2 has projecting connecting bars 12 below the receivers 3 for engagement in correspond- ing connecting grooves 13 of the catch hooks 11. The connecting bars 12 contain a transverse bore 21 for receiving a transverse pin 22 shown in Figure 10.
As can be seen in Figure 10, the catch hook 11 contains two limbs 23 which are spaced apart from each other and between which the connecting groove 13 is formed to receive the connecting bar 12. In the two limbs 23 there are bores 24 in alignment with each other for receiving the transverse pin 22. The transverse pin
22 is fixed to the support 2 via two circlips 25. The catch hook 11 is designed in such a way that it can be removed via the transverse pin 22 but is fixed to the support 2 and cannot be pivoted about the transverse pin 22. In the previous em-
bodiment, the catch hooks 11 are also fixed to the support 2 and cannot be pivoted,
but can be easily dismantled if necessary.
List of reference signs 1 Quick changer 2 Support 3 First receiver 4 Second receiver Contact surface 6 Guide bore 7 Locking element 8 Side part 9 Receiver opening Catch device 11 Catch hook 12 Connecting bar 13 Connecting groove 14 — Outer contact surface — Inner contact surface 16 Receiver 17 Receiver 18 Connecting element 19 Front edge of the catch hook Front edge of the connecting bar 21 Cross bore 22 Cross pin 23 Limb 24 Bore Circlip