Coupling device for work tools in telehandlers

The present invention relates to a coupling device for work tools in telehandlers (or telescopic handlers) and related telehandlers.

Telehandlers are work machines for lifting goods and people which change their use depending on the equipment which is connected to the lifting boom of the machine.

A tool-holder plate is articulated on the free end (head) of the arm, which carried out the function of connecting the interchangeable equipment to the machine.

Various work tools can be connected to such a head, such as forks, forks with spreader and shifter, grippers of various types, hooks, winches, jib extensions with hook and winch, man baskets, jib extensions with man basket, buckets, buckets with claw, concrete mixing buckets, sweepers, snow blades and other known work tools.

This equipment can have hydraulic movements which can be controlled by the operator in the car and operated hydraulically, furthermore, they can have electrical drives, sensors, and electrical/electronic controls which exchange electrical signals and information with the machine.

To enable the hydraulic movements which can be controlled from the car, hydraulic hoses must be connected between the equipment and the free end of the boom.

To enable the drives, electrical/electronic controls, and the exchange of electrical signals and information between equipment and machine, a series of electrical cables must be connected through a multi-pole socket.

Therefore, at the equipment/lifting boom interface, there are different types of connections between equipment and machine so that the interchangeable equipment is correctly connected to the machine:

In the current state of the art, the mechanical connection requires locking and interlocking and serves to ensure that the equipment does not disengage during the work steps.

The coupling is made by the operator controlling the machine (from the car or with radio control), but the interlocking can be done by hand or with a locking/unlocking system controlled from the car.

The tubes are normally coupled by hand (one at a time), as is the socket, if any.

A need felt in the industry is to make the coupling/uncoupling of equipment from the head of the lifting boom easier and, at the same time, to allow a greater versatility of such machines by allowing the use of as much equipment as possible.

An aim of the present invention is to fulfil these (and other) needs of the prior art, within the framework of a simple, rational and cost-effective solution.

Such aims are achieved by the features of the invention set forth in the independent claim. The dependent claims outline preferred and/or particularly advantageous aspects of the invention.

For the above-mentioned aims, the invention, in particular, provides a coupling device for coupling work tools to a telescopic boom of a telehandler, comprising:

Thanks to such a solution, a particularly quick and complete coupling/uncoupling of the work tool from the telescopic boom, viz., which has both the mechanical connection and the hydraulic/electrical connection, can be carried out in just a few seconds, allowing the operator to stay seated in the driver's car or in a remote position with respect to the coupling device, operating on an integrated joystick control or radio remote control.

Furthermore, the coupling/uncoupling of the work tool from the telescopic boom occurs in a particularly clean manner, both for the operator, who does not have to get his/her hands dirty by picking up hydraulic hoses or sockets which can be dirty after having fallen to the ground, and for the connectors themselves, which, being positioned on board the coupling plate and the tool-holder plate, are not subject to falling to the ground and are therefore protected from any dirt or water deposits which—in the case of hydraulic connectors—would otherwise contaminate the hydraulic oil, causing damage to the hydraulic circuit components of the telehandler and work tool and—in the case of electrical connectors—which could otherwise cause false contacts, short circuits or incorrect connections, compromising the correct operation of the telehandler and work tool.

Furthermore, the coupling/uncoupling of the work tool from the telescopic boom is particularly safe, as the all mechanical, hydraulic and/or electrical connections occur in a guided and correct manner, without the possibility of error (even accidental, due to human intervention), making one simple and fast movement with no risk of incorrect connections.

Furthermore, the coupling/uncoupling of the work tool from the telescopic boom occurs in a particularly intelligent and intuitive manner, each hydraulic and/or electrical connector is uniquely configured with a unique position to ensure the correct and complete connection between telehandler and work tool.

Again, the coupling/uncoupling of the work tool from the telescopic boom occurs in a modular manner according to the required configuration of the telehandler and the work tools which must be connected to the telescopic boom, in fact it is possible to configure the coupling device, according to needs, with:

Furthermore, the coupling/uncoupling of the work tool from the telescopic boom thus designed is alternately compatible, allowing most conventional (commercial) work tools to be adapted to the above-described coupling device with simple expedients (viz., installing the connectors on the existing locking cylinder).

The locking cylinder can, as in the case illustrated, have an essentially horizontal extension direction (i.e., parallel to the oscillation axis of the telescopic boom of the telehandler), however, it cannot be ruled out that the extension direction can be substantially vertical (or however at right angles to the oscillation axis of the telescopic boom of the telehandler according to the construction requirements).

Advantageously, each first connector and each second connector can have its respective connection axis parallel and eccentric with respect to the central axis of the locking cylinder.

Advantageously, the one or more first connectors and the one or more second connectors can comprise, as mentioned above, one or more hydraulic connectors for the passage of a hydraulic fluid and/or one or more electrical connectors for the passage of an electrical power line and/or electrical signals.

Furthermore, advantageously, the coupling device can comprise centring means configured to centre each second connector with respect to the respective first connector during the translation from the disconnection position to the connection position.

For example, the stroke of the connector-holder plate towards the connection position can be divided into at least three successive steps of which:

Advantageously, the centring means can comprise one or more centring pins, preferably conical, more preferably multi-conical, mounted on the connector-holder plate or the coupling plate (in the example on the connector-holder plate) and adapted to fit axially within the respective centring holes made in the coupling plate or in the connector-holder plate (in the example made in the coupling plate).

Alternatively or additionally, the centring means can be integrated with the at least a first connector and/or at least a second connector, which is of the self-centring type.

Advantageously, the connector-holder plate and/or each of the second connectors can be movable in translation with respect to the piston from a forward position, in which the connector-holder plate and/or each of the second connectors is distal from the seat pad, to a rearward position, in which the connector-holder plate and/or each of the second connectors is proximal to the seat pad, as opposed to pushing means (which thus push towards the forward position), preferably elastic ones.

Thanks to such a solution, the stroke of the connector-holder plate towards the connection position can comprise a fourth (and final) step (subsequent with respect to the first three above), in which it carried out an extra stroke (forced by the elastic means) to compensate for transverse misalignments.

In practice, the extra stroke allowed to the connector-holder plate and the aforesaid elastic means allow to achieve a closing/connection force acting on each second connector and respective first connector sufficient to counteract the hydraulic and/or other disruptive forces when the connectors are engaged/connected (and pressurised). The extra stroke allows to have a more secure connection which ensures that, when the locking cylinder is fully extended and in the locking position, each hydraulic and/or electrical connector is fully and securely connected.

As part of such a solution, the connector-holder plate can advantageously be mounted on a sleeve coaxially fitted on the piston and sliding axially thereon between the rearmost and forward positions, said pushing means comprising a (helical) spring interposed between the piston and the sleeve (and acting therebetween, exerting an axial elastic thrust).

For instance, the spring is radially interposed between the piston, externally thereto, and the sleeve, internally thereto, and is axially interposed between a fixed shoulder defined on the piston and a movable shoulder defined inside the sleeve.

Advantageously, then, the locking cylinder can be of the double-acting type and can comprise a (single or double) seat pad and two opposite pistons, on each of which a respective connector-holder plate is mounted with at least one or more second connectors each aligned, along the extension direction, with a respective first connector fixed to the coupling plate.

Thanks to such a solution, the implementation can be compact and effective.

Advantageously, there are two (piloted) non-return valves in series in the seat pad. In fact, the hydraulic thrust of the hydraulic connectors tends to distance the hydraulic connectors and thus the connector-holder plate from the first connectors during operation.

The presence of such two non-return valves counteracts/limits such a phenomenon.

As part of such a solution, each piston subdivides the inner chamber of the seat pad into two environments, of which:

a first environment, whose expansion determines the stroke of the respective piston from a retracted position to an extracted position, anda second environment, whose expansion determines the stroke of the respective piston from the extracted position to the retracted position;to control the stroke of each piston between the extracted and contracted position,a valve unit is provided, which comprises:

Thanks to such a bracket, a mutual movement between the tool-holder plate and the coupling plate is prevented which could interfere with the connector-holder plate and, therefore, the breakage thereof or of the second connectors carried by it during the approach steps preparatory to the mutual coupling/uncoupling between the tool-holder plate and the coupling plate.

Advantageously, at least one between the tool-holder plate and the coupling plate can comprise first sensor means configured to detect a position of correct alignment of the locking cylinder with respect to the locking seat along the extension direction.

Again, at least one between the tool-holder plate and the coupling plate can comprise second sensor means configured to detect a parameter indicative of the type of work tool which is connected to the coupling plate.

Advantageously, then, at least one between the tool-holder plate and the coupling plate can comprise third sensor means configured to detect the correct connection of one or more second connectors with one or more first connectors and/or the correct positioning of the piston in the locking position.

According to an advantageous aspect of the invention, an electrical switch device for opening/closing an electrical emergency circuit can be mounted on the connector-holder plate.

Telehandlers are also typically used with work tools which can be man baskets, which contain a telehandler control station/console located on the basket, so as to allow the operator to conduct the telehandler not only from the driver's car (where a main control station/console is provided), but also on board the work tool, viz., the basket. The two control stations (car or basket) can only be selected alternatively for safety reasons. Always for safety reasons, both the car and the control station on the basket are provided with an emergency stop switch (viz., an ‘emergency button’). In order to connect (in series) the emergency stop switch of the basket with the emergency stop switch of the telehandler (car), the coupling device comprises a first connector and a second electrical connector which electrically connects the work tool (basket) and the telehandler. When the work tool (basket) is disconnected from the telescopic boom of the telehandler (and the first electrical connector is disconnected from the second electrical connector), the electrical contact formed by them necessarily opens, thus a situation occurs similar to the one in which the emergency stop switch of the work tool (basket) is pressed and, for example, the telehandler would stop. To overcome such a drawback, the presence of the aforesaid electric switch device allows to close the circuit when the work tool (basket) disconnects from the telescopic boom of the telehandler (and the first electrical connector disconnects from the second electrical connector), preventing the telehandler from shutting down and, vice versa, allows to open the circuit by electrically interconnecting the two emergency stop switches when the work tool (basket) connects to the telescopic boom of the telehandler.

As part of such a solution, the emergency electrical circuit may be provided with an additional limit switch on the work tool, which can be manually operated by the user to stop the operations of the telehandlerand/or the telehandler itself under emergency conditions;

on the emergency circuit there is a similar main limit switch, for instance arranged in the driver's car of the telehandler, which can be manually operated by the user to stop the operations of the telehandler and/or the telehandler itself under emergency conditions; andthe electrical switch device:

Again, advantageously, the electrical switch device can be a device chosen in the group constituted by a micros or microswitch, an electro-operated switch, a magnetic proximity sensor, an induction sensor and any electrical/electronic device that can perform the function of a switch.

For the same aims and advantages as above, the invention provides a telehandler, comprising:

With particular reference to such figures, a telehandler or telescopic handler has been globally referred to as.