GB2135258A - Stabilizing assembly for mobile cranes - Google Patents

Abstract

A stabilizing assembly mounted on a mobile crane, comprising a stabilizing support 21 mounted on the frame of the machine, which support is adjustable, in position and coupled to a motor-operated adjusting device 3 connected to a source of power. The adjusting device comprises an electro-pump unit placed close to the stabilizing support, the power source being electrical and connected to the electric motor and a hydraulic jack being coupled to the stabilizing support. <IMAGE>

Description

SPECIFICATION Stabilizing assembly for mobile machines The invention relates to a stabilizing assembly for mobile machines.

A number of machines are equipped with stabilizers which operate when certain works are being conducted, to prevent the machine from tipping over, consequently to reactions resulting from those works. Such is the case with mobile cranes and mechanical shovels.

According to the prior art, a stabilizing assembly mounted on a mobile public works or handling machine comprises a stabilizing support mounted on the frame of the machine, whose position is adjustable with respect to that frame, between a position where it rests firmly on the ground and an off-the-ground position, and coupled to this effect to a motor-operated adjusting device which is selectively connected to a primary source of power and comprises at least an electric motor situated close to said stabilizing support, the primary source of power being a source of electrical power selectively connected to at least said one electrical motor, said assembly further comprising a substantially horizontal telescopic beam with at least two elements - a first element which is fixed on the frame, and a second element which supports the stabilizing support - whereas the motor-operated adjusting device is mounted on one of said elements other than the first.

It is the object of the present invention to overcome the disadvantages of the currently known hydraulic stabilizing devices, which are situated away from the source of pressurized fluid and connected thereto by means of very long pipes which, in machines with a cab structure, have to go through a pivoting joint, by providing an electropump unit close to each stabilizing assembly, this eliminating the necessity of using the pivoting joint and considerably reducing the length of the fluid supply and delivery pipes.

To this effect, in the stabilizing assembly according to the invention, the stabilizing support being of the telescopic type, is constituted by a sliding guide mounted on said last element of the beam and by a leg mounted for sliding with respect to said guide, a hydraulic jack being placed between the sliding guide and the leg, and the adjusting device comprising an electro-pump unit, whose electric motor is selectively connected to said source of electrical power and whose pump is selectively connected to said hydraulic jack.

The following advantageous dispositions are also preferably adopted: - according to a first embodiment of the invention, the substantially horizontal telescopic beam is provided with a telescopic hydraulic jack, whereas said jack is selectively connected to said pump; - according to a second embodiment, two pulleys are mounted for rotating on said two elements of the beam, whereas a cable rests in reverse motion on said two pulleys and is wound on a winding drum mechanically coupled by way of a clutch member, to the shaft of said electric motor.

-the motor-operated adjusting device is mounted on said last element.

The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which: -Figure 1 is a simplified cross-section of a first embodiment of a stabilizing assembly according to the invention; -Figure 2 is the diagram of the circuit controlling the assembly of Figure 1; -Figure3 is a simplified cross-section of a second embodiment of the stabilizing assembly according to the invention; and -Figure 4 is the diagram of the circuit controlling the assembly of Figure 3.

Referring first to Figures 1 and 2, these give a partial illustration of a machine 1. This machine is a mobile crane whose chassis 2 is equipped with rolling members 4 and with a stabilizing assembly 5.

This assembly is constituted by a horizontal telescopic beam in two sections 6 and 7, beam section 6 being fixed, generally be welding, to chassis 2, whereas a double-acting hydraulic jack 8, is pivotally mounted via spindles 9, on the two beam sections.

Said jack comprises two separate chambers 10 and 11, the pressurized fluid supply to chamber 10 corresponding to the extension of beam section 7 with respect to beam section 6 and out thereof, and complementarily, the supply of chamber 11 corresponds to the retraction of beam section 7 inside beam section 6. A guide 12 of vertical axis 13 is fixed on the outer end of beam section 7. A bore 14 provided in a flange 15 formed at the lower part of guide 12 guides the sliding, in parallel to axis 13 of cylinder 23, of a jack 16 of which the piston rod is secured(17), by its upper part, to said guide 12, by means of a tie-piece 18. Two separate chambers 19 and 20 are provided in the cylinder 15, their respective supply in pressurized fluid causing the extension or retraction of cylinder 23 with respect to guide 12.

In addition, stabilizing support 21 is fitted to the lower end of cylinder 23 and, in the illustrated example, is firmly resting on the ground 22 from which it has lifted (in combination with three other assemblies 5 provided on the chassis 2) the rolling members 4.

Hydraulic jacks 8 and 16 are connected to an electro-pump unit 3, which unit is fixed on beam section 7, supplied with electrical power and remotely controlled by means of flexible electric cables 24 from a control board 25 situated inside the operator's cab of the machine 1, for example.

The detail of this installation is given in Figure 2 which shows that the electro-pump comprises: - a pump 26, - an electric motor 27 driving the pump 26, -two electro-valves 28 and 29, - a fluid tank 30.

The delivery pipe 31 of pump 26 is connected to electrovalve 28. Two pipes 32,33 connect said electrovalve 28 to chambers 10 and 11, respectively, of jack 8; a pipe 34 connects the two electro-valves 28 and 29; and, a pipe 35 connects electro-valve 28 to the tank 30. Two pipes 36, 37 connect, via the piston rod of jack 16, electrovalve 29 to chambers 19, 20, respectively, of jack 16; two pipes 38,39 connecting said electrovalve 29 to pipe 35; and, a pipe 40 connecting the delivery pipe 31 to pipe 35, a calibrated discharge valve 41 being provided on said pipe 40. Electric cables 24 connect terminals 42 of the two control switches 43 and 44 to electromagnets 28 and 29, the switch 44 controlling electrovalve 28 and switch 44 controlling electrovalve 29. Said switches are situated on control board 25 and connected to a source of electrical power 46.In addition, other cables 24 connect motor 27 to terminals 42, with interposition of diodes control 47.

This electrical circuit is in fact a conventional circuit.

The embodiment illustrated in Figures 3 and 4 only differ from those illustrated in Figures 1 and 2 by the means used to control the telescoping of beam section 7 with respect to beam section 6. The elements found are therefore the same except for the jack 8 and its control device, replaced by the assembly described hereinafter.

Two return pulleys 48 and 49 are mounted for rotating on supports 50, 51 integral with beam sections 6,7 respectively. A cable 52 rests in reverse motion on pulleys 48,49 and has its two ends wound on the same drum 53 so that the "wound" length of one end during a rotation of said drum substantially corresponds to the "unwound" length of the other end. Said drum 53 is connected to the driving shaft of the electrical motor 27 via a clutch member 54 which is electrically-controlled (24) by being connected to the control and supply cables of said motor 27 by means of diodes 55. Note that the motor 27 must be reversible, or, at least, must enable to drive drum 53 in rotation in both directions. Obviously, switch 43 is replaced by a switch 43a controlling both the motor 27 and clutch 54 in combination.

Delivery pipe 31 of pump 26 is directly connected to electro-valve 29, which valve is in turn connected with the tank 30 via a pipe 35a (similarto pipe 35 in the embodiment of Figures 1 and 2). Pipe 40 is connected to pipe 35a.

There now remains to define the three positions of each electrovalve 28 and 29.

The three positions of electrovalve 28 of Figure 2 correspond: - the first position, to causing pipes 31 and 32 and pipes 33 and 35 to communicate: to closing off pipes 33 and 35; to closing off pipe 34 and to extending beam section 7 with respect to beam section 6; - the second position, to closing off pipes 32,33 and 35; to causing pipes 31 and 34 to communicate; and to immobilizing beam section 7 with respect to beam section 6; and -the third position to causing sections 31 and 33 and sections 32 and 35 to communicate; to closing off section 34; and to retracting beam section 7 inside beam section 6.

The three positions of electrovalve 29 of Figure 2 correspond: - the first position, to causing pipes 34 and 37 and pipes 36 and 38 to communicate; to closing off pipe 39; - the second position, to closing off pipes 36,37, 38; and to causing pipes 34 and 39 to communicate; and - the third position, to causing pipes 34 and 36 and pipes 37 and 38 to communicate; and to closing off pipe 39.

The three positions of electrovalve 29 of Figure 4 correspond: -the first position, to causing pipes 31 and 37 and pipes 36 and 35a to communicate; to closing off pipe 39; and to lifting support 21 off the ground; - the second position, to closing off pipes 36,37, 35a; to causing pipes 31 and 39 to communicate; and to immobilizing support 21 with respect to chassis 2; and - the third position, to causing pipes 31 and 36, and pipes 37 and 35a to communicate; to closing off pipe 39, and to lowering support 21 with respect to chassis 2.

The aforedescribed embodiments are simple to work, as explained hereafter.

According to the embodiments of Figures 1 and 2, the driver of the machine, by actuating switch 43, on the one hand places electrovalve 28 in its first or in its third position, depending in which way he actuates the switch, and on the other hand, controls automatically, through one of the diodes 47, the starting of electric motor 27 and as a result of pump 26. Said pump thus supplies either chamber 10 or chamber 11 of jack 8. For example, it supplies chamber 10, and beam section 7 extends out of beam section 6. If the driver also actuates switch 44, he places electrovalve 29 in its first or in its third position, say for example in its third position, which will permit to the pressurized fluid to reach chamber 19 of jack 16 and thus to lower support 21 firmly on the ground. The reverse operations obviously enable to retract the support 21.

The embodiments shown in Figure 3 and 4 work similarly, and even identically as far as jack 16 is concerned. It is also found that the motor 27 is started either directly by actuating switch 43a or indirectly by the control switch 44 of electrovalve 29.

Moreover, switch 43a controls clutch 54, enabling it to transmit the movement driving the motor 27 to the drum 53 in one direction or in the other. It is thus possible to chose either to retract orto extend beam section 7 with respect to beam section 6.

In both embodiments, the unit 3 controlling the telescoping of the beam section 7 with respect to beam section 6, and the positioning (lifting or lowering) of support 21, is situated on assembly 5, and even secured to beam section 7. The driving energy, which is of electrical nature (46), has been transported by supple cables 24, this eliminating the need for expensive and bulky pivoting joints such as used in the all-hydraulic systems.

The resulting simplification of the circuits controlling the stabilizers not only contributes to reducing production costs, it also reduces break-down risks.

The invention is in no way limited to the embodiments of the description given herein-above and on the contrary covers any variants that can be brought thereto without departing from its scope or its spirit.

Claims (8)

1. A stabilizing assembly mounted on a mobile public works or handling machine such as a crane or mechanical shovel of the type comprising a stabilizing support mounted on the frame of the machine, whose position is adjustable with respect to that frame, between a position where it rests firmly on the ground and an off-the-ground position, and coupled to this effect to a motor-operated adjusting device which is selectively connected to a primary source of power and comprises at least an electric motor situated close to said stabilizing support, the primary source of power being a source of electrical power selectively connected to at least said one electrical motor, said assembly further comprising a substantially horizontal telescopic beam with at least two elements - a first element which is fixed on the frame, and a second element which supports the stabilizing support - whereas the motor-operated adjusting device is mounted on one of said elements other than the first, stabilizing assembly wherein the stabilizing support is of the telescopic type, constituted by a sliding guide mounted on said last element of the beam and by a leg mounted for sliding with respect to said guide, a hydraulic jack being placed between the sliding guide and the leg, and the adjusting device comprising an electropump unit, whose electric motor is selectively connected to said source of electrical power and whose pump is selectively connected to said hydraulic jack.

2. A stabilizing assembly according to claim 1, wherein the substantially horizontal telescopic beam is provided with a telescopic hydraulic jack, whereas said jack is selectively connected to said pump.

3. A stabilizing assembly according to claim 1, wherein the motor adjusting device is mounted on said last element.

4. A stabilizing assembly according to claim 1, wherein two pulleys are mounted for rotating on said two elements of the beam, whereas a cable rests in reverse motion on said two pulleys and is wound on a winding drum mechanically coupled by way of a clutch member, to the shaft of said electric motor.

5. A stabilizing assembly substantially as hereinbefore described with reference to and as shown in Figures 1 and 2 or in Figures 3 and 4 of the accompanying drawings.

6. A stabilizing assembly mounted on a mobile machine, comprising a stabilizing support mounted on the frame of the machine, which support is adjustable in position and coupled to a motoroperated adjusting device connected to a source of power, the adjusting device comprising an electropump unit placed close to the stabilizing support, the power source being electrical and connected to the electric motor and a hydraulic jack being coupled to the stabilizing support.

7. A stabilizing assembly having a stabilizing support of the telescopic type, which is constituted by a sliding guide mounted on an element of a telescopic beam and by a leg mounted for sliding with respect to said sliding guide, a hydraulic jack being placed between the sliding guide and the leg, and an adjusting device comprising an electro-pump unit whose electric motor is selectively connected to a source of electrical power and whose pump is selectively connected to said hydraulic jack.

8. Any novel integer or step, or combination of integers or steps, hereinbefore described and/or as shown in the accompanying drawings, irrespective of whether the present claim is within the scope of or relates to the same or a different invention from that ofthe preceding claims.