GB1603623A - Hydraulically operated jib crane - Google Patents

Description

(54) HYDRAULICALLY OPERATED JIB CRANE (71) We, LINER LIMITED formerly THE LINER CONCRETE MACHINERY CO. LIMITED, a British Company, of Park Road Works, Park Road, Gateshead 8, Tyne & Wear do hereby declare the invention for which we pray that a Patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: This invention is concerned with load handling vehicles having load raising means for instance, a telescopic boom with load supporting means at its outer end.

Forklift vehicles are commonly provided with modified lifting carriages having moveable parts adapted for specific jobs. Most modified carriages are offered as additional items for forklift trucks having specialist uses e.g. for handling logs. steel billets and like loads. In the past when such machines were required to incorporate a crane, mechanical and/or hydraulic winches were out of necessity, placed on the vehicle chassis and a telescopic boom was fitted with ropes directed from the drum of the winch through a series of pulleys to the end of the boom and over a final pulley to lift the load. Such an arrangement is inconvenient when the winch is not required. The machine itself incorporates the winch, the topes, and all the pulleys which have to be stored and housed whilst the machine is being used in its other functions.There is also the problem of the rope lengthening whilst a telescopic boom is being shortened and the rope shortening as the telescopic boom is being lengthened.

It is an object of the present invention to provide a load handling vehicle having a telescopic boom with an improved arrangement of lifting mechanism at the outer end of the boom.

According to the present invention a load handling vehicle comprises a chassis having ground wheels, a prime mover for providing motive power and a telescopic boom with a supporting carriage assembly at its outer end, wherein a hoisting attachment is connected to the carriage assembly and wherein the hoisting attachment includes an inclined lattice work jib enclosing a winch mechanism and control means for the winch mechanism whereby a load can be raised and lowered at will by means mounted on the attachment.

A further object of the invention is to provide for the winch mechanism to be drivable by an hydraulic motor housed therewithin, with a brake so that the load is held in a fail-safe position when the drive is neither driving it up nor causing its descent.

A preferred embodiment of the invention will now be described by way of example with reference to the accompanying drawings, wherein: Figure 1 is a side view of a load handling vehicle embodying the invention; Figure 2 is a front view of the vehicle of Figure 1.

As shown in Figure 1 a load handling vehicle has a chassis 1, carrying an engine 2 with reduction gearing 3 and four wheels 4.

A driver's cab 5 is provided on the chassis and a telescopically extensible and retractable boom 6 is carried on the chassis 1 by substantial supporting arms 7. Rams 8 are provided for raising and lowering the boom 6.

The boom carries, at its outer end 9, an attachment support plate 10, which is pivoted on the outer end 9 of the boom 6. The support plate 10 carries a hoisting attachment 11 connected to a rectangular support frame 12 which has detents for securing it to the support plate 10. The support plate 10 and the support frame 12 form a supporting carriage assembly. The support frame 12 carries an inclined lattice work jib 13, comprising four main struts 14 forming an inclined pyramid, and bracer struts 15 ex tending across the pyramid. A pulley carrier bracket 16 is supported at the apex of the pyramid shaped jib 13, and carries a pulley 17 in a loop in the bracket 16. A hoist cable 18 is passed over the pulley 17, and is wound on a winch drum 19 carried within the framwork of the lattice work job 13, the inner end of the cable 18 being anchored to one of the struts 14 at 20.The outer end of the cable 18 carries a lifting hook.

The winch drum 19 is driven by a hydraulic pump or motor 21 (Figure 2) which is driven by fluid from the vehicle hydraulic system which includes the rams 8.

The winch drum 19 is braked by a pawl 22, which cooperates with a ratchet (not shown) on the winch drum 19 and the pawl 22 is operated by a pawl operating ram 23, which is pivoted at one end to the support frame 12.

Referring to Figure 3 accompanying the provisional specification hydraulic lines 40, 41 are connected between the hydraulic motor 21 and a hydraulic master cylinder on the vehicle and hydraulic lines are connected to the pawl ram 23 for operating pawl 22 and for returning fluid to the motor 21.

The winch drive, normally an hydraulic motor, may be carried on a sub-frame of the lattice work jib and may be motivated through the main hydraulic supply lines by which it is served, control being carried out by an operator in the cab 5. A dual arrangement of control sensors may be provided preferably actuated by adjacent levers 24 to facilitate synchronicity when a load is being lifted or descended and to provide fail safe braking of the winch motor.

The hydraulic or other winch motor 21 and brake may be housed in a casing for the winch whilst, and this preferably with large installations, a separate motor may be carried and mounted detachably in cases where this is desirable e.g. from spatial considerations or for facilitating its maintenance. The separate motor when used may be housed in the hoisting attachment 11.

A return conduit is provided extending from the hydraulic winch motor to the circuit line to which the carriage responds by tilting, with a non-return valve for preserving uni-directional flow and avoiding leakage of hydraulic fluid.

An advantage of hydraulic or other local motor drive for the winch attachment is the obviation of operative wires or cables which become tangled and the avoidance of further devices for minimizing such tangling e.g.

by taking up their slackness.

WHAT WE CLAIM IS: 1. A load handling vehicle comprising a chassis having ground wheels, a prime mov er to provide active power and a telescopic boom with a supporting carriage assembly at its outer end wherein a hoisting attachment is connected to the carriage assembly and wherein the hoisting attachment includes an inclined lattice work jib enclosing a winch mechanism and control means for the winch mechanism whereby a load can be raised and lowered at will by means mounted on the attachment.

2. A load handling vehicle according to claim 1 wherein the control means includes an hydraulic motor with a brake so that the load is held in a fail-safe condition when the load is not being moved.

3. A load handling vehicle according to claim 1 or 2 wherein the supporting carriage assembly includes an attachment support plate pivoted to the outer end of the boom and supporting the hoisting attachment.

4. A load handling vehicle according to claim 3 wherein the hoisting attachment is connected to a rectangular support frame and wherein the inclined lattice work jib includes main struts forming an inclined pyramid and bracer struts extending across the pyramid shaped jib, a pulley carrier bracket supported at the apex of the pyramid shaped jib and a pulley mounted in the bracket.

5. A load handling vehicle according to claim 4 wherein a hoist cable is passed over the pulley and is wound on to a drum forming part of the winch mechanism carried within the framework of the jib, the cable being anchored to one of the main struts.

6. A load handling vehicle according to claim 5 wherein the winch drum is braked by a pawl which cooperates with a ratchet on the winch drum, the pawl being operated by an hydraulically controlled pawl operating arm which is pivoted at one end to the jib framework.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. tending across the pyramid. A pulley carrier bracket 16 is supported at the apex of the pyramid shaped jib 13, and carries a pulley 17 in a loop in the bracket 16. A hoist cable 18 is passed over the pulley 17, and is wound on a winch drum 19 carried within the framwork of the lattice work job 13, the inner end of the cable 18 being anchored to one of the struts 14 at 20. The outer end of the cable 18 carries a lifting hook. The winch drum 19 is driven by a hydraulic pump or motor 21 (Figure 2) which is driven by fluid from the vehicle hydraulic system which includes the rams 8. The winch drum 19 is braked by a pawl 22, which cooperates with a ratchet (not shown) on the winch drum 19 and the pawl 22 is operated by a pawl operating ram 23, which is pivoted at one end to the support frame 12. Referring to Figure 3 accompanying the provisional specification hydraulic lines 40, 41 are connected between the hydraulic motor 21 and a hydraulic master cylinder on the vehicle and hydraulic lines are connected to the pawl ram 23 for operating pawl 22 and for returning fluid to the motor 21. The winch drive, normally an hydraulic motor, may be carried on a sub-frame of the lattice work jib and may be motivated through the main hydraulic supply lines by which it is served, control being carried out by an operator in the cab 5. A dual arrangement of control sensors may be provided preferably actuated by adjacent levers 24 to facilitate synchronicity when a load is being lifted or descended and to provide fail safe braking of the winch motor. The hydraulic or other winch motor 21 and brake may be housed in a casing for the winch whilst, and this preferably with large installations, a separate motor may be carried and mounted detachably in cases where this is desirable e.g. from spatial considerations or for facilitating its maintenance. The separate motor when used may be housed in the hoisting attachment 11. A return conduit is provided extending from the hydraulic winch motor to the circuit line to which the carriage responds by tilting, with a non-return valve for preserving uni-directional flow and avoiding leakage of hydraulic fluid. An advantage of hydraulic or other local motor drive for the winch attachment is the obviation of operative wires or cables which become tangled and the avoidance of further devices for minimizing such tangling e.g. by taking up their slackness. WHAT WE CLAIM IS:

1. A load handling vehicle comprising a chassis having ground wheels, a prime mov er to provide active power and a telescopic boom with a supporting carriage assembly at its outer end wherein a hoisting attachment is connected to the carriage assembly and wherein the hoisting attachment includes an inclined lattice work jib enclosing a winch mechanism and control means for the winch mechanism whereby a load can be raised and lowered at will by means mounted on the attachment.

2. A load handling vehicle according to claim 1 wherein the control means includes an hydraulic motor with a brake so that the load is held in a fail-safe condition when the load is not being moved.

3. A load handling vehicle according to claim 1 or 2 wherein the supporting carriage assembly includes an attachment support plate pivoted to the outer end of the boom and supporting the hoisting attachment.

4. A load handling vehicle according to claim 3 wherein the hoisting attachment is connected to a rectangular support frame and wherein the inclined lattice work jib includes main struts forming an inclined pyramid and bracer struts extending across the pyramid shaped jib, a pulley carrier bracket supported at the apex of the pyramid shaped jib and a pulley mounted in the bracket.

5. A load handling vehicle according to claim 4 wherein a hoist cable is passed over the pulley and is wound on to a drum forming part of the winch mechanism carried within the framework of the jib, the cable being anchored to one of the main struts.

6. A load handling vehicle according to claim 5 wherein the winch drum is braked by a pawl which cooperates with a ratchet on the winch drum, the pawl being operated by an hydraulically controlled pawl operating arm which is pivoted at one end to the jib framework.