Abstract:
The invention concerns a coupler comprising a cam ( 211 ) for locking a tool ( 100 ) with the coupler ( 200 ), characterized in that the cam ( 211 ) comprises for bringing the cam into a locking position, an articulation ( 213 ) with a connecting rod ( 209 ) itself connected through a bearing ( 206 ) to a piston ( 209 ) mobile in a bore ( 203 ) of the coupler body ( 200 ), said piston being subjected to the action of a spring ( 208 ), a chamber ( 220 ), opening on to a conduit ( 223 ), being formed by the piston ( 205 ) and the base of the bore ( 203 ), and means ( 215 ) for being connected to an unlocking object for applying an unlocking torque on the cam.

Description:
FIELD OF THE INVENTION 
       [0001]    The field of the invention relates to a coupler or coupling device allowing the rapid attachment of an implement, bucket or similar implement, at the end of the articulated arm of an excavation machine or hydraulic shovel or similar construction machine. The invention relates more particularly to the method of unlocking the coupler with the implement. 
       BACKGROUND OF THE INVENTION 
       [0002]    Heavy construction machines like excavation machines or hydraulic shovels comprise at the end of an arm a deformable parallelogram, moved by a cylinder, which allows the rotation and movement of an implement, for example a shovel. This implement is advantageously attached removably by means of a coupler, also called a “quick-attach” coupler. 
         [0003]    Known via patent number FR 2 657 596 granted to Morin Frères is a device for the quick attachment of a bucket on a hydraulic shovel. The device disclosed is a coupler which allows the attachment of a bucket to the end of the articulated arm of the construction machine without the intervention of anyone other than the driver of the machine, and without the latter having to leave his cabin. The coupler is attached to the articulated arm and consists of two hooks docking with a cylindrical beam secured to the bucket. The position of the bucket in the hooks is maintained by an automatic locking system. The system for locking the coupler on the bucket comprises at least one cam mounted rotatably on the coupler and driven by a spring to come into contact with a bearing face of the bucket. Unlocking is achieved manually by the driver of the machine, with the aid of a key forming a lever arm. Such a coupler is reliable and efficient but patent FR 2 657 596 discloses a manual locking without giving the possibility of adapting a hydraulic unlocking device. 
         [0004]    Known through patent EP 0 671 513 granted to Morin Frères is a coupler of the same type as that of patent FR 2 657 596. This coupler comprises in addition a hydraulic unlocking device, unlocking therefore being achieved from the cabin by the driver of the machine. This coupler is notable in that it allows locking and unlocking of the implement remotely by the driver of the machine but patent EP 0 671 513 proposes a complex device capable of hydraulic unlocking and very far by its principle from a strictly manual unlocking device. 
         [0005]    The technical problem for the manufacturer of couplers of one of the two above types is that manufacturing parts for a hydraulic unlocking coupler or for a manual unlocking coupler is specific to the method of unlocking the coupler. Furthermore, the existing devices require the user to choose his unlocking device on first principles. These disadvantages penalize the manufacturer in terms of logistics and cost of the unlocking function. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0006]    The object of the present invention is to propose a coupling device whose unlocking, in order to separate the implement from the coupler, is carried out by a manual device or by a hydraulic device in a mixed manner thanks to structures comprising a maximum of identical components in order to allow optimization of industrial manufacture and to be able to adapt the coupler device for hydraulic or mechanical operation. 
         [0007]    This objective is achieved by a coupler comprising:
       means for attachment to an arm of a heavy construction machine,   hooks for supporting a beam of an implement,   a cam rotatably mounted on a coupler body and arranged to come into contact with a bearing face of the implement in at least one position for locking the implement with the coupler,
 
characterized in that:
   the cam is driven toward its locked position by means of a spring in compression between a stop device mounted in a bore of the coupler body and a first face of a piston that can move in said bore, the spring pushing the piston connected, via a first articulation, to a connecting rod also linked to the cam via a second articulation,   a chamber is formed by the piston and a bottom of the bore opened by a supply duct, the piston comprising a peripheral groove,   the cam comprises means of connection with an unlocking object which makes it possible to apply an unlocking torque to the cam.       
 
         [0014]    One object is to propose a hydraulic unlocking of the coupler. 
         [0015]    According to this object, a seal being placed in the peripheral groove of the piston, means for delivering pressurized liquid into the chamber are connected via a connector to the supply duct in order to act on a second face of the piston opposite to the first face subjected to the action of the spring and to push the connecting rod driving the cam from the locked position to an unlocked position, in order to achieve a hydraulic unlocking of the coupler. 
         [0016]    Another object is to propose a manual unlocking of the coupler. 
         [0017]    According to this object, the unlocking object is a key interacting with the cam and comprising a lever to which an unlocking force is applied in order to apply the unlocking torque and rotate the cam toward an unlocked position, compressing the spring pressing between the piston and the stop by means of the force transmitted via the connecting rod in order to manually unlock the coupler. 
         [0018]    According to another feature, a plug closes the supply duct, the piston being mounted without seal in the bore and comprising a drill hole or a longitudinal groove leading into the peripheral groove and placing the chamber in communication with a portion of the bore containing the spring. 
         [0019]    According to another feature, the cam comprises on the one hand a surface of revolution along its axis of rotation, placed about a shaft held in bearings of the coupler body, the cam comprising on the other hand a contact surface designed to interact with the bearing face of the implement, the contact surface of the cam having an eccentric profile, on a plane perpendicular to its axis of rotation, whose radius substantially increases in the opposite direction from locking. 
         [0020]    Another object relates to innovations for the two methods of operation in hydraulic or manual unlocking. 
         [0021]    According to another feature, the hooks and the coupler body are made from one and the same machined cast part. 
         [0022]    According to this object, the articulations between the connecting rod and the piston, between the connecting rod and the cam and between the cam and the coupler are achieved by means of materials lubricated for life. 
         [0023]    According to another feature, a cover resting on the coupler and on a flat lateral face of the cam, perpendicular to the axis of rotation of the cam, closes off in a sealed manner a space comprising the connecting rod, the spring, and a portion in which the articulation between the connecting rod and the cam takes place. 
         [0024]    According to another feature, the coupler comprises at least a second bore, a second piston, a second spring, a second supply duct and a second connecting rod in order to achieve a dual control of the cam. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0025]    The invention, with its features and advantages, will emerge more clearly on reading the description given with reference to the appended drawings in which: 
           [0026]      FIG. 1  represents a view in perspective of an example of a mixed unlocking coupler according to the invention; 
           [0027]      FIG. 2  represents a view in section of an example of a mixed unlocking coupler according to the invention; 
           [0028]      FIG. 3  represents a side view of an example of a coupler according to the invention used by an excavation machine; 
           [0029]      FIG. 4  represents a side view of an example of a coupler according to the invention placed on an arm and connected to a bucket; 
           [0030]      FIG. 5  represents a view in perspective of an example of a coupler according to the invention connected to a bucket; 
           [0031]      FIGS. 6 to 8  represent side views of an example of a coupler during automatic coupling, with three successive positions of the cam; 
           [0032]      FIG. 9  represents a view in section of an example of a device for controlling a coupler according to the invention, in hydraulic unlocking mode; 
           [0033]      FIG. 10  represents a side view of an example of a manual unlocking key; 
           [0034]      FIG. 11  represents a view in section of an example of a device for controlling a coupler according to the invention, in manual unlocking mode via the key represented in  FIG. 10 ; 
           [0035]      FIG. 12  represents a view in section passing through the axis of rotation of the cam of an example of a coupler according to the invention; 
           [0036]      FIG. 13  is a view in perspective of the piston of an example of a coupler according to the invention; 
           [0037]      FIG. 14  is a partial view in section of the piston placed in the bore of an example of a coupler according to the invention; 
           [0038]      FIG. 15  is a view in perspective of an example of a coupler with two pistons and two connecting rods according to the invention; 
           [0039]      FIG. 16  is a view in perspective of an example of a coupler fitted with a manual unlocking key. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0040]    The invention will now be described with reference to the aforementioned figures. As shown in  FIGS. 3 and 4 , the coupler ( 200 ) is attached to an arm ( 3 ) which is connected to a boom ( 2 ) of a hydraulic shovel ( 1 ) or a similar machine. The coupler ( 200 ) according to the invention makes it possible to hold a bucket ( 100 ) fixedly. After the coupler ( 200 ) and the bucket have been locked together, the arm ( 3 ) can carry out a rotary movement of the assembly consisting of the bucket and the coupler, by acting on two axes ( 31 ) parallel with one another, held in bearings in lateral sides ( 225 ) of the coupler. 
         [0041]    As shown in  FIGS. 1 and 2 , a lower portion forms a jaw ( 211 ,  201 ), provided for connecting a bucket ( 100 ) or another implement. The jaw is formed by two semi-circular grasping hooks ( 201 ) and by at least one locking cam ( 211 ) pivoting on an axis ( 202 ), about a shaft ( 221 ). The hooks ( 201 ) are connected together by at least one transverse bridging element ( 224 ) of the coupler body, and two bosses ( 226 ) are provided, in the coupler body, opposite to the hooks ( 201 ) in order to be traversed by two drill holes ( 212 ) and in order to serve as a support for the shaft ( 221 ) for rotation of the cam ( 211 ). The hooks ( 201 ) of the semi-circular type are coaxial and accommodate a coupling beam ( 112 ) belonging to the implement, such as for example the bucket ( 100 ). The locking cam ( 211 ) is designed to come into contact on a bearing face ( 110 ) to achieve the locking action. 
         [0042]    The automatic coupling of the bucket to the coupler according to the invention is achieved thanks to the cam ( 211 ) pushed to its locked position under the action of a spring ( 208 ). The arm ( 3 ) of the machine is operated so as to place the grasping hooks ( 201 ) beneath the coupling beam ( 112 ) of the bucket ( 100 ). 
         [0043]    The arm ( 3 ) is then controlled in a vertical translation, in order to lift the implement ( 100 ) that is then oriented relative to the coupler ( 200 ) but free in rotation. Then the arm ( 3 ) is operated so as to cause the coupler ( 200 ) to pivot which places the cam in a position pressing on the snout ( 111 ) connected to the implement, as shown in  FIG. 6 . The snout ( 111 ) is particularly represented on its own with the cam ( 211 ) pressing on the snout ( 111 ). The cam ( 211 ) pushed by the snout ( 111 ) pivots on the shaft ( 221 ) and relatively to the coupler body, in the opposite direction (D 1 ) from locking, until the tip of the cam ( 211 ) is in contact with the tip of the snout ( 111 ) as shown in  FIG. 7 . The snout is also represented on its own with the cam ( 211 ), the tip of the snout encountering the tip of the cam ( 211 ). The contact between the tips is followed by a pivoting in the direction (D 2 ) of locking of the cam ( 211 ) under the action of the spring ( 208 ), a surface, with an eccentric profile, belonging to the cam ( 211 ) pressing on the surface ( 110 ) situated at the end of the snout ( 111 ). The bucket ( 100 ) is then locked with the coupler ( 200 ) as shown in  FIG. 8  in which the cam ( 211 ) and the snout ( 111 ) are also represented on their own in their relative position. 
         [0044]    The hooks ( 201 ) retain the bucket left free to rotate, being oriented under the action of its weight, until locked. After locking, the bucket is held in the hooks and presses both on the eccentric surface ( 214 ) of the cam and against the shaft ( 221 ) of the cam held in the bearings ( 212 ) of the coupler body. The cam ( 211 ) is mounted in rotation relative to the coupler body, the shaft ( 221 ) of the cam ( 211 ) being placed on the side of the opening of the hooks ( 201 ) receiving the beam ( 112 ) of the bucket. In the working position, when a force tending to lock the bucket is applied to the teeth of the bucket, the contact forces are transmitted on the one hand by the surfaces of contact between the beam ( 112 ) and the hooks ( 201 ) and, on the other hand, by the surfaces of contact between the shaft ( 221 ) of the cam and a cradle ( 113 ) of the bucket. The cam is not put under strain and is subjected only to the return torque of the spring constantly taking up the clearance between the surface of contact ( 214 ) of the cam ( 211 ) and the bearing surface ( 110 ) of the snout ( 111 ). 
         [0045]    On the other hand, when a force tending to unlock the bucket relative to the coupler is applied at the end of a tooth, the contact forces are then transmitted via the surfaces of contact between the beam ( 112 ) and the hooks ( 201 ) and by means of the cam ( 211 ) pressing via its contact surface ( 214 ) on the bearing surface ( 110 ) of the bucket. 
         [0046]    The present invention is first of all novel by its structure. The cam ( 211 ) whose locking is automatic is specifically actuated by a connecting rod ( 209 ) connected to the cam via an articulation ( 213 ) with an axis parallel to the axis ( 202 ) of rotation of the cam ( 211 ). Furthermore, the connecting rod ( 209 ) is connected to a control piston ( 205 ), via an articulation ( 206 ), the piston ( 205 ) being able to move in translation in a bore ( 203 ,  FIG. 1 ) made in the body of the coupler ( 200 ). The control piston ( 205 ) is actuated by a spring ( 208 ) which pushes the piston toward the bottom of the bore ( 203 ), the spring ( 208 ), at its other end, pressing against a stop segment ( 210 ). The diameter of the spring ( 208 ) is close to the diameter of the bore ( 203 ) so that the spring ( 208 ) is traversed by the connecting rod ( 209 ) articulated on the cam ( 211 ). Under the action of the spring ( 208 ), the piston ( 205 ) tends to pull the connecting rod ( 209 ) toward the bottom of the bore, causing the cam ( 211 ) to rotate about its axis ( 202 ) to its locked position, in the direction indicated by the arrow D 2 . 
         [0047]    In other embodiments, the spring ( 208 ) presses against a ring screwed into the bore ( 203 ) or against two rods traversing the bore ( 203 ) of the coupler ( 200 ) on each side of the connecting rod ( 209 ). 
         [0048]    In the various locking phases, the spring will be more or less compressed. The contact of the cam ( 211 ) on the snout ( 111 ) will progressively compress the spring as shown in  FIG. 6  up to a value close to the maximum in the position of contact between the tip of the snout and the tip of the cam ( 211 ), represented in  FIG. 7 . The spring then expands to place the cam in a locked position represented in  FIG. 8 . In this position, the piston ( 205 ) is at a non-zero distance from the bottom of its bore ( 203 ), which corresponds to a reserve of travel making it possible to take up the clearance that may occur between the surface of contact ( 214 ) of the cam ( 211 ) and the bearing face ( 110 ) of the snout ( 111 ). 
         [0049]    For the unlocking, a direct action on the cam is possible in the direction (D 1 ) of compression of the spring by means of a manual key ( 400 ) comprising means ( 401 ,  403 ) of attachment to the cam ( 211 ) and a lever ( 402 ) for applying an unlocking force. Specifically, the key is attached to the cam ( 211 ) and presses on the latter, the lever ( 402 ) allowing the user to exert an unlocking torque on the cam about its axis of rotation. This manual unlocking with the aid of the removable key ( 400 ) pressing on the cam ( 211 ) therefore makes it possible to separate the surface ( 214 ) of contact of the cam ( 211 ) from the bearing face ( 110 ) on the implement. A key ( 400 ) mounted on the cam ( 211 ) is, for example, represented in  FIG. 16 . The lever arm ( 402 ) makes it possible for the user to apply an unlocking force ( 4021 ). In a nonlimiting manner, the means for attaching the key to the cam comprise a cylindrical hole ( 401 ) coming around a matching cylindrical nipple ( 215 ) of the cam, a bearing surface ( 403 ) of the key coming into contact with the body of the cam ( 211 ). The key ( 400 ) is then pivoted about the nipple ( 215 ) until its bearing surface ( 403 ) encounters the body of the cam ( 211 ). In a nonlimiting manner, the bearing surface ( 403 ) of the key and the interacting surface of the body of the cam ( 211 ) both have a circular arcuate profile. The key, held around the nipple ( 215 ) and pressing on the body of the cam ( 211 ), is then secured to the cam. The lever arm ( 402 ) on which the user exerts his force ( 4021 ) then makes it possible to exert a torque allowing the cam to rotate about its axis in the unlocking direction (D 1 ). The implement ( 100 ) then separates by its own weight by pivoting in the hooks ( 201 ) of the coupler in order subsequently to be placed on the ground and moved away from the hooks ( 201 ) by control of the arm ( 3 ). 
         [0050]    In another exemplary embodiment, the attachment nipple belongs to the key and is engaged in a hole belonging to the cam. In another exemplary embodiment, the key comprises a gripping finger coming to press against the leading edge of the surface of contact ( 214 ) of the cam ( 211 ) and the body of said cam, in order to exert an unlocking torque. 
         [0051]    In addition, the piston ( 205 ) forms a chamber ( 220 ) with the bore ( 203 ), rendered sealed by a seal ( 207 ,  FIG. 9 ). This expandable chamber ( 220 ) supplied with hydraulic fluid makes it possible to push the piston ( 205 ) compressing the spring ( 208 ). Hydraulic unlocking demands the addition of a control block on the hydraulic shovel making it possible to divert the hydraulic power of the machine to the chamber ( 220 ) of the actuator consisting of the piston ( 205 ) furnished with its seal ( 207 ) sliding in the bore ( 203 ). 
         [0052]    With reference to  FIG. 9 , the oil is brought, via a pipe ( 223 ), through the hydraulic connector ( 204 ), into the bore ( 203 ) in order to move the piston ( 205 ) forward while compressing the spring ( 208 ) toward the stop ring ( 210 ). The piston ( 205 ) in translation pushes the connecting rod ( 209 ) which converts the translation movement of the piston ( 205 ) into a rotary movement of the cam ( 211 ), in the unlocking direction (D 1 ). Hydraulic unlocking is thereby achieved remotely by the operator of the machine. 
         [0053]    The present invention therefore allows two unlocking methods. The transition from the manual unlocking method ( FIG. 11 ) to the hydraulic unlocking method ( FIG. 9 ) is restricted to the addition to the system in manual mode of the seal ( 207 ) and the connector ( 204 ) to the hydraulic circuit. 
         [0054]    The coupler ( 200 ) is for example made by a cast part comprising, in a nonlimiting manner, in its rear portion, the locking device according to the invention. Said device may then be fully integrated into the casting making it possible in particular to protect the cam ( 211 ) and the whole locking system against possible impacts caused by protruding rocks. 
         [0055]    In another exemplary embodiment, the coupler is mechanically welded and machined to produce the same functional surfaces. 
         [0056]    The piston ( 205 ) according to the invention, represented in  FIGS. 13 and 14 , comprises guide surfaces ( 229 ) in the bore ( 203 ) in which the piston ( 205 ) is placed. A cylindrical hole ( 228 ) is made in the piston ( 205 ) and is designed to receive the spindle around which the connecting rod ( 209 ) articulates. The piston ( 205 ) slides in the bore ( 203 ) between an unlocked position in which the spring ( 208 ) is compressed and a locked position in which the piston ( 205 ) is in a position nearer to the bottom of the bore ( 203 ). 
         [0057]    In a method of operation of manual unlocking, the groove ( 227 ) housing the seal ( 207 ) on the periphery of the piston is, for example, empty. The peripheral groove ( 227 ) is similar to a recess around the piston. The piston comprises a channel for the circulation of air connecting the chamber ( 220 ) situated at the bottom of the bore ( 203 ) with the portion of the bore ( 203 ) receiving the spring ( 208 ). This channel is intersected by the groove ( 227 ) for housing the seal ( 207 ). In a nonlimiting manner, the air circulation channel is made by a longitudinal drill hole ( 217 ) or by a longitudinal groove ( 216 ). This channel traverses the piston from one side to the other and emerges in the groove ( 227 ) for housing the seal. In the example of a longitudinal groove ( 216 ) made on the outer face of the piston ( 205 ), the depth of the longitudinal groove does not exceed that of the groove ( 227 ) for housing the seal ( 207 ). Therefore, for the operation in manual mode, the circulation channel allows air to pass from one side of the piston to the other so as not to hamper operation. In this form of execution, the supply duct ( 223 ) may be totally closed in order to protect the piston from external damage. 
         [0058]    In a hydraulic unlocking method, the chamber ( 220 ) forming the actuator is sealed by placing a seal ( 207 ) in the groove ( 227 ) as shown in  FIG. 14 . The longitudinal hole ( 217 ) or groove ( 216 ) are therefore closed by the seal ( 207 ). The supply duct ( 223 ) leads to the outside of the coupler ( 200 ) at a hydraulic connector ( 204 ) designed to be connected to a hydraulic control device. 
         [0059]    A closure cover ( 218 ) is shown to be transparent in  FIG. 1 , in order to show the articulation ( 213 ) of the connecting rod ( 209 ) on the cam ( 211 ). Specifically, to operate maintenance-free, the device must be correctly protected by a fitted closure cover ( 218 ) which provides the seal between the cam ( 211 ) and the body of the coupler ( 200 ) and protects the articulations ( 213 ,  206 ), the piston ( 205 ), the spring ( 208 ) and the connecting rod ( 209 ) from external damage. 
         [0060]    The cover ( 218 ) is for example placed above the articulation ( 213 ) resting against the body of the coupler ( 200 ) and against a face ( 230 ) concentric with the axis ( 202 ) of the cam ( 211 ). 
         [0061]    In another exemplary embodiment, as shown in  FIG. 12 , the cover ( 218 ) is not resting on the cylindrical face ( 230 ) of the cam ( 211 ), but comprises a flat surface ( 219 ) in abutment on the cam, perpendicular to the axis of rotation ( 202 ), producing both a seal and a translation limit of the cam. 
         [0062]    Other technical choices for achieving the seal may be produced and left to the appreciation of those skilled in the art. The present invention has the advantage of not requiring greasing and avoids the addition of greasers which it would be difficult to install in the space provided. The locking and unlocking device comprises, for the articulations of the connecting rod and those of the cam, materials that operate without external greasing or lubrication. The choice of these materials is left to those skilled in the art who will advantageously use filled composite or plastic materials in order to provide this property. 
         [0063]    In a nonlimiting manner, the translation of the cam on its axis is restricted laterally by flat surfaces ( 219 ,  FIG. 12 ) placed close to the shaft ( 221 ) and perpendicular to the latter. These translation limitation surfaces form part, in a nonlimiting manner, of the cover, of the coupler ( 200 ), of the cam ( 211 ) or of additional parts such as seals. 
         [0064]    In a nonlimiting manner, for large-dimension couplers, one and the same cam ( 211 ) may be controlled by two devices according to the invention, the assembly formed by the coupler with its cam being produced symmetrically relative to a longitudinal plane (S), perpendicular to the axis of rotation of the cam, as shown in  FIG. 15 . Therefore the two devices each comprising a bore ( 203 ) associated with a piston ( 205 ) actuated by a spring ( 208 ) and connected in rotation to a connecting rod ( 209 ), are placed on each side of the coupler ( 200 ). An unlocking implement is fitted, for example, in the same manner to a nipple ( 215 ) of the cam in order to apply an unlocking torque to the cam ( 211 ). 
         [0065]    It should be evident for persons conversant with the art that the present invention allows embodiments in numerous other specific forms without departing from the field of application of the invention as claimed. Consequently, the present embodiments must be considered as an illustration, but may be modified in the field defined by the scope of the attached claims, and the invention should not be limited to the details given above.