GB2352709A

GB2352709A - Self-propelled crane

Info

Publication number: GB2352709A
Application number: GB0013200A
Authority: GB
Inventors: John Edward Valla
Original assignee: Valla SpA
Current assignee: Valla SpA
Priority date: 1999-06-07
Filing date: 2000-06-01
Publication date: 2001-02-07
Anticipated expiration: 2020-06-01
Also published as: GB0013200D0; IT246770Y1; FR2794693A3; ITMI990364V0; DE20010030U1; ITMI990364U1; GB2352709B; FR2794693B3

Abstract

A self-propelled crane structure comprises a frame (12) which supports an internal-combustion traction engine (14) connected by means of a drive (16) to its own driving wheels (22), and a jib (36) over the end pulley of which a rope (48) of a winch (46) is run, the rope (48) carrying a hook (50) for performing working operations. On the frame (12) there is further provided an electric traction motor (24) supplied by batteries or power supplies (30), which enables movement of the crane (11), in particular on work sites and/or in covered and/or closed premises. The crane can have a battery charger to enable mains recharging or a current generator operated by a power take off or a second IC engine. Preferably the crane has a balance weight device 52 operated by a hydraulic cylinder device 54 whereby the weight 66 can be carried on the flatbed of the crane or a trailer without external aid.

Description

2352709 SELF-PROPELLED CRANE STRUCTURE The present invention refers to a

self-propelled crane structure.

It is known that traditional self-propelled cranes comprise a vehicle made up of a frame on which a diesel engine is installed. The diesel engine is connected to the wheels for moving the vehicle and, in addition, to a pump which supplies a hydraulic circuit for operating one or more hydraulic actuators consisting usually of a cylinder with rod. The actuator supports and operates an arm or jib of the crane, enabling its rotation in a vertical plane about a pivot which is fixed to the frame of the crane itself. on the frame is installed a winch which carries a rope running over a pulley carried at the free end of the jib of the crane.

The diesel engine enables movement of the selfpropelled crane and, in addition, enables operation of the jib. This means that, in order to use the selfpropelled crane, it is necessary to keep the diesel engine running. This circumstance may prove unfavourable when it is necessary to work on work sites or in covered and/or closed premises in which the use of traditional self- propelled cranes of this kind is not possible or, in any case, is highly inadvisable.

Furthermore, traditional self-propelled cranes are not designed to adapt to loads which may fall within a wide range. This limits the flexibility and operating capacity of the crane.

A purpose of the present invention is to eliminate the drawbacks referred to above by providing a self- propelled crane structure that can be used also on work sites and in covered and/or closed premises without any adverse effects or disadvantages.

Another purpose of the present invention is to provide a self-propelled crane structure that presents flexibility of use and that, in particular, may be adapted also to loads that fall within a substantially wide range of values.

Not the least important purpose of the present invention is that of providing a self-propelled crane structure that is basically simple, safe and reliable.

Claims

These and other purposes according to the present invention are achieved

by providing a self-propelled crane structure according to Claim 1.

The characteristics and advantages of a self- propelled crane structure according to the present invention will emerge more clearly evident from the ensuing description, which is provided purely to give explanatory and non- limiting examples, with reference to the attached schematic drawings, in which:

Figure 1 presents a schematic side elevation of a self-propelled crane according to the present invention; Figure 2 presents a schematic front elevation of the self-propelled crane illustrated in Figure 1; Figure 3 presents a schematic rear elevation of the self-propelled crane illustrated in Figure 1; Figure 4 presents a schematic plan view of the self-propelled crane illustrated in Figure 1; Figures 5 and 5B each present a schematic side elevation of a detail of a driving cab in various examples of embodiment of the self-propelled crane according to the present invention; Figure 6 is a schematic side elevation of a detail of a different example of embodiment of the driving cab of the self-propelled crane according to the present invention; and Figure 7 illustrates a detail of a balance weight of the crane shown in Figure 1.

With reference to the above figures, a selfpropelled crane structure is shown, designated as a whole by the reference number 11.

The self-propelled crane 11 comprises a frame 12 which supports a diesel-driven internal-combustion traction engine 14 for moving the crane 12 during transfer from a depot to a work site, or from one work site to another. The diesel engine 14 is connected to a drive (mechanical or automatic gear change, or hydrostatic power unit) 16 which is connected to a rear axle 20 of the self-propelled crane 11. The axle 20 is provided with a differential (not shown for reasons of simplicity) designed to distribute the torque supplied by the diesel engine 14, for example by means of the mechanical gear change 16 and a shaft 18, on two axle shafts (not shown for reasons of simplicity) which turn the driving wheels 22 of the self-propelled crane 11. In a solution with hydrostatic drive, the hydraulic engines could be connected directly to the wheels. At a point adjacent to the diesel engine 14 and corresponding to the gear change 16, the frame 12 supports an electric traction motor 24. The electric motor 24 drives a reducer 26 which, by means of a shaft 28, is connected to the mechanical gear change 16, or else directly to the differential or to the wheels, for moving the self-propelled crane 11.

The electric motor 24 is supplied by batteries or electric power supplies 30. The battery 30 is moreover connected to a battery charger 32, so that the battery 30 can be recharged from the electric power mains, for example in the plant workshop.

In addition, recharging of the battery 30 can be carried out using a current generator 31 connected to the battery charger 32, which, in various examples, may be applied to the diesel engine 14 or to a power takeoff of the gear change 16, or to a power take-off of a hydrostatic drive.

Alternatively, the current generator 31 can be connected to a second diesel-driven internal-combustion engine 33 supported by the frame 12 of the crane 11 without the function of moving the crane, but with the sole function of operating the current generator 31.

In practice, the battery charger 32 performs the dual purpose of battery charger supplied by the electric power mains and functioning as rectifier, or else is designed to function as an inverter for recharging the battery 30 by transforming the current produced by the generator 31.

In addition, the battery 30 supplies an electric motor-driven pump 34 which operates the hydrodynamic controls of a jib 36. In various examples (not shown for reasons of simplicity and in any case in themselves known), the hydrodynamic controls are operated by means of a pump on the hydrostatic control, or else by means of transmission to a pump from the internal-combustion engine, or else by means of a torque converter or some other means.

The jib 36 is hinged in 38 in one of its own end portions to a support 40 fixed to the frame 12 of the crane 11. In addition, the jib 36 carries a slot 42 in which a hydraulic cylinder 44 for raising the jib 36 is hinged. The jib 36 is telescopic or extendible and is provided, in a manner of itself known, with hydraulic extending cylinders, which, in the present example, are set inside the jib 36 itself, but in other different examples of embodiment may also be set outside the jib 36. In particular, the said cylinders (not shown) are two in number and independent of one another, and communicate, or else are multi-stage (telescopic) cylinders. Of course, the electric motor-driven pump 34 sends oil to the cylinders for moving and extending the jib 36 through distributors, either proportional or manual, so as to impart sensitivity of movement on them.

The crane 11 is provided with a winch 46 on the barrel of which a rope 48 is wound, which carries a hook 50 by means of which working operations are performed. In a first example of embodimentf the winch 46 is housed inside the jib 36, and in particular at the end of the jib close to the hinging point 38.

In a different example of embodiment, the winch 46 is housed on a bracket which is fixed to the frame 12 of the crane 11, and the rope 48 runs over a pulley inside the jib 36, the pulley occupying aposition similar to the position occupied by the winch 46 in the previous embodiment.

The crane 11 is equipped with a -fixed balance weight or with a balance weight device 52 which enables the load on at least one of the axes of the crane 11 to be increased in order to increase the stability of the latter.

The balance weight device 52 comprises a hydraulic cylinder 54 having a flanged end connected to the frame 12 along one of the edges 55 of the latter. The cylinder 54 is connected to a rod 56 which carries a pulley 58 at its own end.

Fixed to the edge 55 of the frame 12 is rope 60 which is wound on the pulley 58 and, furthermore, on a second pulley 62 and a third pulley 64, so that a free end of the rope 60 protrudes from the edge 55 itself.

To the free end of the rope 60 a weight 66 may be hooked, which can be transported by the self-propelled crane 11 itself, or else can be transported to the work site on a trailer drawn by the crane 11.

The crane is provided with a cab 68, inside which all the controls are arranged. A control for positioning the supplementary weight 66 may be located outside the cab 68.

In a first example of embodiment, the cab 68 has a single seat and a single position, but may also be made with two positions, one for transferring the crane and driving it on the road, and one f or working on the work 5 site.

All the controls in the cab 68 can be operated with a single control and are remote controls. In particular, the accelerator of the diesel engine is regulated with a cable system or electronic system, or else with a mechanical control. The speed of the electric motor 24 is regulated by a remote control using an electronic system, for example one of the MOSFET type.

In the example of embodiment described herein the crane 11 according to the invention is equipped with a front, steering, bridge and a rear, traction, bridge. In different embodiments, however, the crane 11 may be equipped with two steering bridges and two traction bridges so as to carry out different types of steering.

For example, it is possible to carry out a steering with a single steering axis (according to the example illustrated), with two steering axes (i.e., with wheels that steer in opposite directions), or else crab steering (i.e., with wheels that steer in the same direction).

Operation of a self-propelled crane structure according to the invention is described below. During movement of the crane on the road or in any case out of doors, the self-propelled crane 11 is driven by the diesel engine 14. 5 In this phase, the battery 30 can be recharged by means of the current generator so as to have the crane immediately operational on the work site. Recharging may be carried out in the same way also when the crane 11 is parked. However, when the crane is stationary and whenever possible, recharging of the battery will be performed preferably from a mains power source.

When the self-propelled crane 11 is on the work site and/or in covered or closed premises, the diesel engine 14 is deactivated, and the electric motor 24 is activated, the latter motor enabling movement of the crane 11. The batteries 30 moreover supply the winch 18 and electric motor-driven pump 34 which operates the jib 36.

The balance weight device 52 makes it possible to balance and guarantee stability of the crane during working operations. This is obtained by hooking the balance weight 66 to the free end of the rope 60; subsequently, by sending the rod out of the cylinder 54 the weight 66 itself is raised at least partially and can thus exert its own counterbalancing action on the crane 11. This balance weight can be raised by the crane 11 itself and laid for its transportation on the flatbed of the crane or on a special trailer.

The self-propelled crane 11 has a hybrid operation which comprises both a first diesel-driven traction engine and a second electric motor for translation. In addition, all the power controls are electrical. This enables use of the crane according to the invention in a highly flexible manner.

In practice, all the materials used, as well as the dimensions, may be any whatsoever according to the technical requirements.

CLAIMS 1. A self-propelled crane structure comprising a frame (12) which supports at least one internalcombustion traction engine (14) connected by means of at least one drive (16) to its own driving wheels (22), and a jib (36) over the end pulley of which a rope (48) of a winch (46) is run, the said rope (48) carrying a hook (50) for performing working operations, characterized in that on said frame (12) there is provided an electric traction motor (24) supplied by batteries or power supplies (30), which enables movement of the crane (11), in particular on work sites and/or in covered and/or closed premises.
2. A self-propelled crane structure according to Claim 1, characterized in that said electric motor (24) operates at least one reducer (26) forthe movement of said self-propelled crane (11).
3. A self-propelled crane structure according to Claim 1, characterized in that it comprises a battery charger (32) connected to said battery (30) in such a way that said battery (30) can be recharged from an electric power mains source.
4. A self-propelled crane structure according to Claim 3, characterized in that it comprises at least one current generator (31) connected to said battery charger (32) for recharging said battery (30), said current generator (31) being applied to said internalcombustion engine (14) or to a power take-off of said gear change (16), or to a power take- off of a hydrostatic drive.
5 5. A self-propelled crane structure according to Claim 4, characterized in that it comprises at least one second internal-combustion engine (33) connected to said current generator (31).
6. A self-propelled crane structure according to Claim 4, characterized in that said battery charger (32) performs the dual function of battery charger, supplied by the electric power mains, or else is designed to function as an inverter for recharging said battery (30), transforming the current produced by said 15 current generator (31).
7. A self-propelled crane structure according to Claim 1, characterized in that said winch (46) is housed inside said jib (36), and in particular at its end close to one point of hinging (38) of said arm (36) 20 to said frame (12) of said crane (11).
8. A self-propelled crane structure according to Claim 1, characterized in that said winch (46) is housed on a bracket fixed to said frame (12) of said crane (11), said rope (48) running over a pulley inside 25 said jib (36).
9. A self-propelled crane structure according to -13-..

Claim 1, characterized in that it is provided with a balance-weight device (52) which enables the load to be increased at least on one axis of said crane (11) to increase the stability of the latter, to lift and transport said balance weight on the flatbed of the crane itself or on a special trailer without the aid of external means.
10. A self-propelled crane structure according to Claim 9, characterized in that said balance-weight device (52) comprises at least one hydraulic cylinder (54) having one flanged end connected to said frame (12) at least along one of first edge (55) of the frame, said cylinder (54) being associated with a rod (56) which carries, at its end, a pulley (58), a second rope (60) being fixed to said first edge (55) of said frame (12), said second rope (60) being wound around said pulley (58) and moreover around a second pulley (62) and around a third pulley (64) so that a free end of said second rope (60) protrudes from said edge (55), at least one weight (66) being hookable to said free end of said second rope (60)
11. A self-propelled crane structure, as described and as illustrated, and for the purposes specified herein.