Quick-release fastener for construction machinery

The present invention relates to a construction machine, for example a mechanical shovel, to which a tool, such as a bucket, is attached in a movable manner, by means of a device forming a quick coupler consisting of a coupler, also known as a quick-release fastener, attached to the machine, particularly to an arm of the machine, and a connection device attached to the tool to engage with the coupler. The present invention also relates to a device forming a quick coupler of this kind and a coupler or quick-release fastener of this kind.

The term ‘bucket’ will be used below. However, the term ‘bucket’ must be understood to also cover any other tool or equipment intended to be mounted on a construction machine by means of the quick-release fastener and connection device.

Traditionally, the connection device that is intended to be attached to the bucket comprises an element in the form of a cradle having a base element and two lateral left and right flanks, between which at least one trunnion, in particular, in the case of what are known as reversible devices, two parallel, cylindrical, circular trunnions or axles, extend, the trunnion or each trunnion being arranged such as to each be able to engage with a respective hook originating from the coupler for coupling between the coupler or quick-release fastener and the connection device to thus achieve coupling of the bucket to the arm of the construction machine.

These couplers of the prior art are dangerous in use. In particular, means of locking the quick-release fastener to the connection device are provided. If these locking means were to release or break, they would then no longer lock the quick coupler and the bucket may release and drop suddenly, which, on construction sites where people are present, may prove to be extremely dangerous.

The object of the present invention is to overcome the disadvantages of the prior art by proposing a device forming a coupler, in particular a so-called reversible coupler, as well as a coupler or quick-release fastener to be used in a device of this type, which are safer to use.

According to the invention, a device forming a coupler comprising a coupler, or quick-release fastener, which is intended to be attached to a construction machine, such as a mechanical shovel, a connection device, which is intended to be attached to a tool, such as a bucket, coupling means intended to couple the quick-release fastener to the connection device and locking means intended to lock the coupling; the connection device comprising at least one trunnion, preferably two trunnions, which are in particular parallel with one another; the coupler comprising a base body in which a rear receiving cavity for the or one of the trunnions is defined, a lever being mounted such that it moves between a closed position in which it holds the trunnion or one of the trunnions in the rear receiving cavity and an open position in which it does not hold the trunnion, the locking means being arranged such that they block the lever in the closed position, characterised in that a rear plate forming a stop is mounted on a rear end of the coupler such that, in the closed position of the lever, part of the lever abuts against the rear plate.

Preferably, the part of the lever that abuts against the rear plate comprises a lug, in particular mounted such that it pivots in relation to the lever, a tooth protruding from the lug, a notch being formed in the rear plate, and, in the closed position, the tooth is received in the notch.

In particular, the lug is mounted on an upper rear end of the lever.

Preferably, the tooth protrudes downwards from the lug and the notch is formed on the rear side of the rear plate.

Preferably, the lever is mounted such that it pivots.

Preferably, the lever is mounted such that it is mobile in translation, in particular in the horizontal direction from the front side to the rear side, the locking means being arranged such that they push the lever in a translation movement to move it into a closed position, in particular to the blocked state.

In particular, the rotating axle of the lever is received in at least one oblong through window, in particular two through windows formed in the respective lateral flanks of the base body.

Preferably, the locking means comprise at least one spring, in particular two springs, which is/are attached on the one hand to the body of the coupler, in particular a rear part of the body of the coupler, and on the other hand to a front end part of the lever.

Preferably, in the closed position of the lever, in particular in the blocked state, the or each spring extends in the horizontal direction.

In particular, the or each spring is a tension spring which is intended to draw the lever backwards.

Preferably, the lever comprises at least one upper branch, in particular two left and right lateral upper branches, and at least one lower branch, in particular two left and right lateral lower branches, which extend towards the rear from the axle of the lever, the or each upper branch extending further towards the rear than the or each lower branch, each pair of lower and upper branches, left and right respectively, defining a respective C-shaped cavity, in particular with an opening facing rearwards, in which the trunnion is received in the closed position.

In particular, the lever comprises at least one front branch, in particular two right and left front branches, extending towards the front from the axle of the lever, the or each branch being composed of a proximal portion followed by a distal portion, which extends in an inclined manner in relation to the proximal portion.

Preferably, the front branch or each front branch pass though a respective through opening, in particular two respective left and right openings, of the base body to emerge from the upper surface of the base body, the front end or each front end of the distal portion or each distal portion being attached to a front end of a respective spring, while the other end of the spring or each spring is attached to a respective stud originating from the upper face of the base body, in particular substantially in the region of the upper rear edge of the base body.

Preferably, the lug is mounted in the region of the rear end of the upper rear branch or the rear ends of the upper rear branches.

In particular, the lug comprises, on either side of its pivot axle, a rear part and a front part, the front part having smaller dimensions than the rear part, and thus a lower weight, such that the lug, under the effect of its own weight, tends to swing in a direction such as to cause its rear part to fall downwards.

In particular, the lug axle is attached to the lever by means of a support component in the form of a bridge attached to the two upper faces of two rear upper branches of the lever.

Preferably, a torsion spring is mounted such as to act on the lug, in particular such as to load the rear part downwards.

Preferably, the rear part comprises an upper protrusion.

Preferably, the rear receiving cavity is open towards the bottom.

Preferably, the connection device comprises a lower base plate and on the upper edge two lateral flanks, two trunnions, spaced apart from one another, being attached to the two flanks such as to extend between them at a distance from the base plate.

Preferably, the coupling means comprise at least one front hook, in particular two left and right lateral front hooks, protruding from the front of the base body and the connection device comprises two trunnions, one of which is intended to be received in the rear receiving cavity and the other in a front receiving cavity or cavities defined by the front hook or hooks.

Preferably, the coupler, or quick-release fastener, comprises a base plate from which two lateral flanks protrude downwards, each flank terminating on the front side in a respective hook.

The present invention also relates to a construction machine comprising a lifting element, in particular a lifting arm, and a tool, in particular a bucket, and a device forming a quick coupler according to the invention, the coupler or quick-release fastener being attached to the lifting element of the machine, while the connection device is attached to the tool.

The figures show a quick-release fastenerwhich engages with a connection device, which is itself attached to a bucket.

The connection devicecomprises a base plate from the upper face of which two lateral flanksextend in a perpendicular manner. Two parallel, cylindrical-circular-shaped trunnions, topand bottomrespectively (when the bucket is placed on the ground), are attached to the two flanks such as to extend from one to the other at a distance from the base plate to allow two front hooksoriginating from the quick-release fastener to pass between them and the base plate.

The quick-release coupler is shown in detail, in an exploded view, in. The only items missing from this figure are the two lateral wingssupporting the axles enabling the quick-release fastenerto be attached to the arm of the lever of a construction machine such as the arm of a mechanical shovel.

The quick-release fastenercomprises a bottom body comprising an upper base plateand two lower lateral flanks(only one is visible on) originating from the upper plate, each flankterminating, on a side subsequently referred to as the front side, in a respective front hook.

A componentforming a lever is mounted such that it pivots with respect to an axleparallel to the axle of the trunnions when the quick-release fastener and the connection device are locked together. The axleis connected to the quick-release fastener but is able to undergo a limited movement through the oblong openingsformed by the lateral flanks.

Two rollerswhich are able to roll from one side to the other of the oblong openingsare attached by bolts (shown in the figure but not referred to by reference numerals) on each side of the axle. However, this attachment does not prevent relative rotation of the rollers around the axle, thus allowing the axle, and thus also the lever, to be driven in translation, even if said lever does not pivot.

The levercomprises two upper left and right branchesand two lower left and right branches, which extend backwards from the axle. The upper branches extend further backwards than the lower branches. The left upper and lower branches define a left-hand, C-shaped space, the opening of which is turned towards the back and in the same manner, the right upper and lower branches define a right-hand C-shaped space, the opening of which is turned towards the back.

Two right and left front branchesextend forwards from the axle. They each consist of a proximal portionfollowed by a distal portion, which extends in an inclined manner in relation to the proximal portion, in particular substantially at 90°. The two distal portionspass through two through openings, left and right respectively, formed through the base plateof the quick-release fastener to emerge from the upper surface of the base plate and are each fixed to a front end of a spring, left and right respectively, while the other respective ends of each springare attached to two left and right studsin the form of hooks originating from the upper face of the base plate, substantially in the region of the rear edge of the base plate. The springsare tension springs that tend to draw the front ends of the distal portions backwards. Two left and right coversare attached by bolts (shown but not referred to in the figure) against the lateral flanksto conceal and/or protect the openingsfrom the exterior, in particular to prevent earth getting lodged in the oblong openingsand impeding movement of the rollers.

A rear platewhich substantially takes the shape of a rectangular parallelepiped extends transversely between the two lateral flanks, substantially in the region of the rear edge of the base plate. The rear plateis attached to the flanks by bolts and holes, shown inbut without reference numerals. A rear notchis formed centrally in the upper edge of the rear plate, on the rear side of the plate.

In longitudinal section, the rear face of the rear plateis substantially rectilinear and vertical. The front face of the rear platein turn comprises a first substantially vertical lower portion, followed by an upper portion inclined upwards towards the rear.

A component, referred to as a lug, is mounted on the lever, between the left and right upper branches, being able to pivot with respect to the lever, with respect to an axle, parallel to the axleand which extends into the space between the two upper branchesof the lever. The axleof the lugis attached to the leverby means of a support componentin the form of a bridge attached to the upper face of the upper branchesby corresponding bolts and holes shown onbut not referred to by reference numerals. A torsion springis attached such that it acts on the lug. The lugcomprises, on either side of the axle, a rear partand a front part, the front parthaving smaller dimensions than the rear part, and thus a lower weight, such that the lug tends, under the effect of its own weight, to swing in a direction such as to cause its rear part to fall downwards (anticlockwise direction in the figures). The torsion springis mounted such as to act on the lugin a manner that also loads the rear part downwards. The rear partcomprises an upper protrusionand terminates in a rear tooth, which projects towards the bottom of the remainder of the rear part and which has dimensions enabling it to penetrate the rear notchof the plate. A groovewhich is intended to receive the upper protrusionis formed in the lower face of the base platewhen the upper branchesof the leverare positioned such that they are abutted against the lower face of the base plate.

On the front side, the quick-release fastenerdefines two respective receiving cavitiesfor one or other of the two trunnionsandof the connection device. Two receiving cutoutsfor the other of the two axlesandof the connection device are formed in the lateral flankson the rear side of the plate.

Each hookcomprises a partforming a rod that extends at the front end of one of the respective flanks, parallel to the plane of the plate, and terminates in a partforming a coupling head, which extends upwards from the end of the partforming a rod. Each hookthus defines, with the front edges of the lateral flanks, two cavitiesin which one or other, depending on the direction in which they are inserted in relation to the bucket, of the two axlesandoriginating from the connection deviceattached to the bucketare intended to be inserted through respective upper openings. The cavitycomprises a respective recessed areacreated in the front edge of each lateral flankand with a shape that complements at least half of the circular transverse cross-section of the axlesandsuch that, when the axleororiginating from the bucket is inserted in the receiving cavitiesthrough the openings, the axle can be inserted in the recessover at least half of its transverse cross-section, i.e. over a sector with an angle of at least 180°.

In relation to the lower, or bottom, surfaceof each cavity, the uppermost endof the partforming the head extends in the vertical direction at least in the region of the centre of the cross-section of the axleorwhen this is located in the cavity, in particular above the centre, and in particular substantially in the region of the diameter, or even above the diameter. Similarly, the uppermost endof the surface of the part forming the head of the side of the cavityextends above the centre of the axleor, in particular at a height between the radius and the diameter, or could even extend substantially to a height equal to the diameter of the axle.

The respective dimensions of the axles of the trunnions of the connection device attached to the bucket and the cavitiesformed by the hooksare selected such that once the headpart has been inserted beneath the axleorof the bucket, as shown onfor example, and the operator of the lifting machine causes the coupler to turn in the wrong direction, i.e. in the clockwise direction in, the shoulder formed between the edgeof the openingand the upper edgeof the plateof the quick-release fastenerwill abut against the edges of the flanksof the connection device originating from the bucketsuch that even though the operator has started to raise the bucket away from the ground, the quick-release fastener and the connection device can no longer pivot in relation to one another, the top part of the hook thus still remaining beneath the axle and preventing this axle, and thus also the bucket, from falling back to the ground, the stop in the region of the shoulder preventing any sudden withdrawal of the axle from the cavities. This stop comes into play beyond a rotation in the wrong direction of approximately 15°.

If the bucket operator causes the quick-release fastener to turn in the right direction (in the anticlockwise direction in) to lock the coupler to the connection device of the bucket, the cutoutscover the other axleof the bucket from above.

As the operator causes the quick-release fastener to pivot to insert the second axlein the cutouts, the second axleof the bucket comes to bear against the upper branchesof the lever, causing said lever to pivot and retreat (towards the front). At the limit of travel, the upper faces of the two upper branchesare parallel with the lower face of the base plateand, at the same time, the lug, which is mounted such that it pivots in relation to the leveris pushed by the springstowards the rear such that its toothpasses over the upper edge of the rear plateand penetrates the notch.

This backwards movement, under the effect of the springs, also drives the rear lower branches of the lever, which thus pass beneath the trunnion, trapping it in the cavity.

Thus, as shown on, the quick-release fastener is locked to the bucket. This is a well secured locking mechanism, and, in particular, even if one or more springswere to break or become detached, the quick-release fastener of the bucket would not become unlocked, thus being held in a secure manner.

The toothhas a rear surface that is inclined upwards and backwards such that when the springspush the leverbackwards again once this is in position with the rear upper branches in the horizontal direction, the pushing force, in conjunction with the inclined shape of the rear face of the tooth, causes the lug to pivot away from the torsion spring and allows the toothto pass into the notch.

shows a wrenchenabling the fastener to be unlocked once said fastener has been locked, i.e. once the toothhas swung into the notchof the plate.

The wrench comprises an extended handle(only part of said handle is shown in the figure) terminating in a head part comprising two upperand lowerlateral arms and a central projection. A studextends transversely from the end of the upper arm, in a direction perpendicular to the handle such that it can penetrate an eyelet formed in a studoriginating from the upper face of the plateof the fastener. A noseoriginates from the lower lateral arm, said nose extending towards the upper arm.