GB2024946A

GB2024946A - Support device, comprising a support arm and a tubular base longitudinally adjustable by hydraulic means

Info

Publication number: GB2024946A
Application number: GB7923608A
Authority: GB
Original assignee: Wibau GmbH
Current assignee: Wibau GmbH
Priority date: 1978-07-06
Filing date: 1979-07-06
Publication date: 1980-01-16
Also published as: DE2829631A1; DE2829631B2; IT7924001A0; IT7921994V0; IT1121969B

Abstract

A hydraulically adjustable support device for construction equipment has a support arm 1, a support tube 3 on the arm, a piston rod 5 in the support tube, the upper ends of the piston rod and support tube being interconnected, and a foot tube 9 movably guided in the support tube and on the piston rod. The foot tube slides on a piston 6 on the lower end of the piston rod and forms a hydraulic cylinder. Conduits 11, 16 in the piston rod enable the cylinder to be pressurized to extend and retract the foot tube 9, which may have a pad 18 at its bottom. <IMAGE>

Description

SPECIFICATION Support device, comprising a support arm and a tubular base longitudinally adjustable by hydraulic means The invention relates to a support device, comprising a support arm and a tubular base, longitudinally adjustable by hydraulic means and connected to said support arm. Such devices are commonly associated with building machinery, such as concrete pumps or the like, equipped with jibs, for example concrete distributor masts.

Support devices of this kind are known in which a conventional hydraulic jack is connected to the support arm which is pivotably attached to a vehicle or machine frame and a piston rod of said hydraulic jack provides the support function on the support arm directly via a thrust plate, or indirectly, forming an adjustable member on a support foot.

These devices suffer from the disadvantage of awkward and complex handling, an expensive construction involving the use of separate actuating jacks and support feet, and a substantial expenditure in terms of labour and material.

Furthermore, individual parts are relatively easily damaged in the rough service conditions encountered on a building site.

It is an object of the invention to provide a support device which is more suited to operation in rough building site conditions and in which the supply of hydraulic medium, the piston rod and the seal elements are substantially protected against external effects.

The invention provides a hydraulically adjustable support device comprising an upright hydraulic cylinder, a piston in the cylinder attached to an upwardly extending piston rod, a support tube attached to the piston rod and encircling the piston rod and the cylinder, the cylinder being guided on the piston rnd and in the support tube, a support arm attached to the support tube, and hydraulic fluid conduits within the support tube and communicating with respective ends of the cylinder, whereby the cylinder can be extended and retracted relative to the support tube.

In a preferred embodiment of the invention, in a support tube, associated with a support arm, there is disposed an axially arranged piston rod which is fixedly connected to the top tube and, is equipped with a piston, with at least one passage, having valve control on the inlet side, extending substantially axially or axially parallel with the piston rod and opening on the piston underside, and with at least one passage, having valve control on the inlet side, also extending substantially axially or axially parallel with the piston rod but opening radially above the piston; by means of the piston as well as by means of an outer and an inner foot tube guide there is accommodated in the support tube a cylindrical foot tube which is supported on the piston rod so that it can slide axially with respect to the piston in both directions on being biased by different hydraulic charging; and the valve or valves for the passage or passages extending through the piston underside into the bottom chamber and for the passage or passages extending through the piston topside into the top chamber is or are constructed so that the bottom chamber beneath the piston can be filled with hydraulic medium when the foot tube is extended and the top chamber above the piston can be emptied of hydraulic medium and that reversed opening conditions for the valves are obtained when the foot tube is retracted.

A device of the present kind, in which the piston is stationary relative to the support tube, and the thrust cylinder, constructed as a foot tube, slides substantially within the support tube, offers substantial protection against external effects due, to conditions which prevail on a building site.

Such an embodiment permits permanent installation of the hydraulic supply and return ducts which lead to the valves and carry the hydraulic medium in the support arm, and ensures a clearly defined force transmission along the axial orientation of the support tube.

Wear and maintenance are thus substantially reduced and handling is simplified.

Preferably, the valves are installed in the top end of the support tube. This still further seduces the risk of damage; the valves are advantageously constructed as interchangeable inserts which can be introduced into the support tube end.

To ensure a clearly defined support action it is convenient to connect the foot tube or cylinder via a joint pin to a bottom plate. It is particularly advantageous but not always necessary for such connection of the bottom plate to be by means of a universal joint. In the interests of self-cleaning facilities of the outer guide for the foot tube and for the foot tube itself it is convenient to construct the outer guide as a three-point bearing, more particularly a three-point ball bearing.

The scale ofthe piston end of the internal foot tube guide with respect to the foot tube and to the piston rod respectively are preferably designed for a pressure of 200 bar.

The invention will be further explained by reference to an embodiment illustrated in the accompanying drawing.

The drawing shows part of a support arm 1 or outrigger, which is usually pivotably attached to a vehicle and which is associated with a support foot 2 comprising a support tube or cylinder 3 whose upper end 4 is centrally and fixedly connected to a piston rod 5 with a piston 6 within the tube 3.

A foot tube or cylinder 9, which is guided on the piston rod 5 by an inner guide 7 at the top of the cylinder 9, and in the support tube 3 by an outer guide 8 in the bottom of the tube, surrounds the piston 6. The outer guide 8 is advantageously constructed as a three-point bearing. The chamber 10 in the cylinder 9 above the piston 6 can be charged with hydraulic medium 14 or can be emptied, via a passage 11 which is controlled by a valve 12, while the chamber 13 beneath the piston 6 can be charged with hydraulic medium or can be emptied, via a passage 16 which is controlled by a valve 15.

If the chamber 10 is charged with hydraulic medium through the valve 12 and the passage 1 1, the cylinder 9 will be retracted (raised) and at the same time the chamber 12 beneath the piston will be emptied of hydraulic medium via the passage 16, the valve 15 being open. The hydraulic control procedure is reversed when the cylinder 9 is to be extended (lowered). At the bottom the tube base 9 is movably connected to a bottom plate 18 via a joint pin 17.

A dimensioned example is given below to provide further explanation.

The apparatus is designed for a maximum support load of 1 1 tons. The support tube 3 is 140 x 10 mm. To the tube end 4 there is welded a tube of 50 x 15 mm, forming the piston rod 5 through which the passages 1 1 and 16, comprising tubes of 8 x 1.5 mm, extend to the chambers 13 and 10.

The piston (including the piston seals) has a diameter of approximately 90 mm and the foot cylinder 9, which functions as thrust cylinder and is guided on the piston rod 5 and in the outer tube guide, has a size of 120 x 15 mm. The seals of the piston 6 with respect to the internal surface of the cylinder 9 and the seals of the inner guide 7 of the cylinder 9 with respect to the piston rod 5 are designed for a pressure of 200 bar; the tube lengths are adapted so as to provide a maximum stroke of approximately 600 mm and at maximum extension approximately 60% of the length of the cylinder 9 still remains within the support tube 3.

The apparatus is designed for a maximum support load of 11 tons corresponding to a piston surface area of 63.6 cm2 and a pressure of approximately 173 bar.

Claims

1. A hydraulically adjustable support device comprising an upright hydraulic cylinder, a piston in the cylinder attached to an upwardly extending piston rod, a support tube attached to the piston rod and encircling the piston rod and the cylinder, the cylinder being guided on the piston rod and in the support tube, a support arm attached to the support tube, and hydraulic fluid conduits within the support tube and communicating with respective ends of the cylinder, whereby the cylinder can be extended and retracted relative to the support tube.

2. A support device as claimed in Claim 1 in which the conduits are within the piston rod.

3. A hydraulically adjustable support device, comprising a support arm and a tubular foot longitudinally adjustable by hydraulic means and connected to said arm, more particularly as associated with building machinery, such as concrete pumps or the like, equipped with jibs, for example distributor masts, characterized in that in a support tube associated with a support arm there is disposed an axially arranged piston rod which is fixedly connected to the top end of the support tube, is provided with a piston and with at least one passage having valve control on the inlet side, extending substantially axially or axially parallel with the piston rod and opening on the piston underside, and with at least one passage having valve control on the inlet side, extending substantially axially or axially parallel with the piston rod and opening approximately radially above the piston; that by means of the piston and by means of an outer and an inner foot tube guide there is accommodated in the support tube a cylindrical foot tube which is supported on the piston rod so that it can slide axially with respect to the piston in both directions by virtue of being biased by different hydraulic charging; and that the valve or valves for the passage or passages extending through the piston underside into the bottom chamber and for the passage or passages extending through the piston top side into the top chamber is or are constructed so that when the foot tube is extended the bottom chamber beneath the piston can be filled with hydraulic medium and the top chamber above the piston can be emptied of hydraulic medium, and reversed opening conditions for the valves are obtained when the foot tube is retracted.

4. A support device according to Claim 3, characterized in that the valves are installed in the top end of the support tube.

5. A support device according to Claim 3 or 4 in which a bottom plate is connected to the foot tube via a joint pin.

6. A support device according to Claim 5, characterized in that the bottom plate is connected to the foot tube by means of a universal joint.

7. A support device according to any of Claims 3 to 6, characterized in that the outer tube guide is constructed as a three-point bearing.

8. A support device according to Claim 7, characterized in that the three-point bearing is a three-point ball bearing.

9. A support device substantially as herein described with reference to the accompanying drawing.