GB2073701A

GB2073701A - Mobile crane

Info

Publication number: GB2073701A
Application number: GB8101602A
Authority: GB
Original assignee: UPTON ENTERPRISES Pty Ltd
Current assignee: UPTON ENTERPRISES Pty Ltd
Priority date: 1980-04-11
Filing date: 1981-01-20
Publication date: 1981-10-21
Also published as: JPS56145093A; DE3112135A1

Abstract

A mobile crane has a base frame 5 adapted to be mounted on road wheels 6 and a jib member 16 pivotally mounted on a leg member 13 connected to and pivotable on the base frame 5. The jib member 16 and the leg member 13 are actuable by respective hydraulic rams 19, 14 mounted on the base frame 5 so as to provide a wide range of outwardly and upwardly located positions e.g. A, B, C, of a fixed hook 18 attached to the outer end of the jib 16. The fixed hook may be substituted by a cable passing over a pulley and operated by a winch mounted on the underside of the jib 16 forward of pivot 21. The outer end of the jib 16 may be telescopic. <IMAGE>

Description

SPECIFICATION Improvements in or relating to mobile cranes The present invention relates to cranes and in particular to mobile cranes adapted to be towed behind a tractor or like vehicle.

A sturdy, compact crane has long been needed in agriculture and light industry, particularly a mobile crane which is simple to operate and is not permanently attached to or forming part of a prime mover, thus allowing other uses of the prime mover.

It is an advantage of the present invention that there is provided a crane having the above features and which can be operated by fluid pressure supplied by a towing vehicle or by a suitable engine driven pump on the crane framework.

According to the present invention there is provided a crane comprising a base frame, a leg member pivotally connected at one end to the base frame and at its other end to a jib member, a first fluid-actuated ram means connected between the base frame and the leg member and a second fluid-actuated ram means connected between the base frame and the jib member, whereby actuation of said first ram means pivots said leg member about said base frame and actuation of said second ram means pivots said jib member about said leg member.

The leg member may be pivotally mounted on a pedestal on the base frame and its ram means connected between the pedestal and a point on the leg member between the ends thereof. The ram means for the jib member may be pivotally connected between the base frame at a location spaced from the pedestal and a point on the jib member between the ends thereof. The locations of the pivotal connections of the ram means on the pedestal, base frame, leg member and jib member are preferably such the the leg member can pivot between a vertical position and a forwardly extending angular position within substantially a 600 arc, and the jib member can pivot between a horizontal position and an upper angular position within substantially a 350 arc.

Suitable fluid pressure connections can extend between the ram means and the source of fluid pressure.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a side elevational view of the mobile crane of this embodiment; and Fig. 2 is a plan view from above of the mobile crane of Fig. 1.

Referring to the drawings, the base frame 5 is mounted on road wheels 6 by axle or stub shaft means located in housing 7. The base frame 5 is generally of box frame structure of elongate configuration and includes strut members 8 connected between frame 5 and housing 7 to provide rigidity of structure. Hitch means 9 are provided at the front end of base frame 5 for connection to a towing vehicle.

A pedestal-type member 10 is fixed, by welding, to the frame at a location forward of the road wheels 6 and includes two pivot points 11 and 12. A leg member 13 is pivotally connected at the forward pivot point 11 and a fluid-operated ram 4 is pivotally connected at the rearward pivot point 12. The other end of ram 14 is pivotally connected to leg member 13 at a point 1 5 approximately two thirds along its length from pivot point 11. The location of pivot point 1 5 is a matter of choice dependant on the desired extent of arcuate movement of leg member 1 3.

A jib member 1 5 is pivotally connected at one end to leg member 13 at pivot point 17 and extends rearwardly of the base frame 5. A hook member 1 8 or the like is attached to the free end of jib member 1 6. A fluid-operated ram 19 is pivotally connected at its lower end to the base frame 5 at a point 20 above housing 7 on the axis of the road wheel axle or stub shaft means, and at its upper end to jib member 1 6 at a point 21 approximately two thirds along its length from the free end of jib member 16. Again the location of pivot point 21 is a matter of choice dependant on the desired extent of arcuate movement of jib member 16.

Suitable hose connections (not shown) are connected between each of rams 14 and 1 9 and a source of fluid pressure, such as a tractor hydraulic pressure system, and the rams may be operated by the tractor driver through the usual valve controls.

Referring to Fig. 1 , the full line illustration of the crane shows the jib member 1 6 in its lowermost position with ram 14 fully extended and ram 19 in its retracted position. In this position leg member 13 engages against support member 25 and when the crane is inoperative with fluid pressure exhausted from ram 14, member 25 serves to support leg 13 and jib 1 6.

When ram 14 is retracted, leg member 13 is raised to substantially vertical position, as shown in broken line illustration A, and with ram 19 held in retracted position, jib member 1 6 moves upward to a horizontal rearward extending position.

From position A, extension of ram 1 9 moves jib member 16 in arcuate manner to broken line position B, and extension of ram 14 brings leg member 13 to its position engaging support member 25 and jib 1 6 moves to broken line position C.

It can be seen that the construction of this embodiment enables the jib to be moved through a wide range of positions by simple operation of ram 14 or ram 19 or a combination of rams 14 and 19.

It will be appreciated that if the crane is to be connected to a towing vehicle which does not have a hydraulic pressure system, a portable engine-driven hydraulic pump may be mounted on the base frame 5 with suitable valve controls for operating rams 14 and 1 9.

The several members of the base frame 5, the leg member 13 and jib member 1 6 are so shaped and constructed as to provide a rigid crane structure capable of withstanding heavy slewing or side forces applied by a load at the end of the jib. In particular the jib may be of box girder type construction, and its outer part between pivot and point 21 and hook 18 may be of telescopic construction to provide extension of the jib for particular applications.

It will also be appreciated that the fixed hook 1 8 at the end of the jib may be substituted by a pulley with a cable running over the pulley and operated by a winch mounted on the underside of the jib forward of pivot pin 21.

Claims

1. A crane comprising a base frame, a leg member pivotally connected at one end to the base frame and at its other end to a jib member, a first fluid-actuated ram means connected between the base frame and the leg member and a second fluid-actuated ram means connected between the base frame and the jib member, whereby actuation of said first ram means pivots said leg member about said base frame and actuation of said second ram means pivots said jib member about said leg member

2. A crane according to claim 1, wherein the leg member is pivotally mounted on a pedestal on the base frame, said first ram means is connected between the pedestal and a point on the leg member between the ends thereof, and said second ram means is connected between the base frame at a location spaced from the pedestal and a point on the jib member between the ends thereof.

3. A crane according to claim 2, wherein the locations of the ram means on the pedestal, base frame, leg member and jib member are such that the leg member can pivot between a vertical position and a forwardly extending angular position within substantially a 600 arc, and the jib member can pivot between a horizontal position and an upper angular position within substantially a 35 arc.

4. A crane according to any one of claims 1 to 3 and including a hook member affixed at the end of the jib member remote from the pivot.

5. A crane according to any one of claims 1 to 3 and including a pulley on the outer end of the jib member, a winch located on the underside of the jib and a hoist cable on said winch and extending over said pulley.

6. A crane according to any one of claims 1 to 5 and including an engine-driven hydraulic pump mounted on the base frame and operatively connected to said first and second ram means.

7. A crane according to any one of claims 1 to 6 wherein said base frame is mounted on road wheels.

8. A crane constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.