GB2051196A

GB2051196A - Powered Support Device

Info

Publication number: GB2051196A
Application number: GB7921121A
Authority: GB
Original assignee: SHAKHTIN NI I PROEKTNOKONSTRUK
Current assignee: SHAKHTIN NI I PROEKTNOKONSTRUK
Priority date: 1979-06-18
Filing date: 1979-06-18
Publication date: 1981-01-14

Abstract

A face supporting device for use in mining comprises two extensible props 2 mounted on a base 1 and carrying a cap 3. Part-spherical heads 4 on the props engage in spherical bearings 5 in the cap and a part- spherical element 8 engages between each prop head 4 and a pair of resilient plates 7 mounted on the cap to restrict lateral tilting of the cap relative to the props. The elements are so arranged that they do not impede longitudinal angular displacement of the cap relative to the props due to the props being extended to different heights. <IMAGE>

Description

SPECIFICATION Powered Support Device This invention relates to a face supporting device, and more particularly to a powered support device which can be used with particular advantage in mining minerals occurring in thin seams.

There are serious problems to be overcome in mechanizing the excavation of minerals from thin seams of a height less than 1 m. The provision of powered supports for use under such mining conditions is extremely important.

According to the present invention there is provided a powered support device comprising a base, two extensible props mounted on the base and having part-spherical heads, a cap carried on the props by part-spherical bearings in which the prop heads are received, resilient means acting between the props and cap for restricting angular displacement of the cap relative to the props, and a part-spherical element with a radius substantially equal to that of the prop heads located between each prop head and said flexible means for transmitting forces therebetween.

The device may have small minimum height and a high hydraulic extensibility factor.

Due to the provision of the part-spherical elements it is possible to locate the resilient means outside the outline of the prop bodies. The articulated joints between the cap and props are not disturbed and the prop bodies can be arranged in the spaces limited by the elements.

As a result the device can be used in mining thin seams since at a minimum structural height the support device can have a maximum hydraulic extensibility, i.e. can serve a wide range of seams with respect to their thickness.

In a preferred embodiment of the invention the device comprises a pair of plates located symmetrically on opposite sides of a vertical plane containing the axes of the props, and each part-spherical element includes projections for bearing against the plates and projections engaged between the plates to prevent rotation of the element about the prop axis.

The projections of the elements bearing against the plates preferably have edges inclined at an angle in the plane parallel to the vertical plane passing through the longitudinal axis of the support device.

The provision of such inclined surfaces on the projections which bear against the plates permits the cap to turn easily relative to the props in the vertical plane when the props are extended at different heights.

With a support device of the above-described construction, the position of the cap or canopy is stabilized against lateral tilting by the resilient plates which are carried by the cap and act on the part-spherical elements which in turn abut against the prop heads. At the same time the cap can turn easily relative to the props in the vertical plane containing the axes of the props, the angular position of the cap in this plane being stable due to the spaced supporting points determined by the prop heads.

Preferably each prop head and associated partspherical element have coaxially, conically tapered confronting surfaces whose generating lines lie on a radius of the element and of the prop head respectively.

Owing to the provision of such tapered surfaces on the prop heads and on their associated elements, each element and prop head form a single articulated joint between the cap and the prop both in the kinematic and power respects. This simplifies the manufacture and repairs of the components of the joint since the tapered surfaces of contact between the head and the element permit transmission of both horizontal and vertical forces from the cap to the props and back as said parts interact during relative motions.

A more complete understanding of the invention will be had from the following detailed description which is given by way of example with reference to the accompanying drawing in which: Figure 1 is a general view of a support device according to the invention; Figure 2 is a section taken along line 1I--II in Figure 1; Figure 3 is a section taken along line Ill-I 11 in Figure 2.

The support device or unit shown in Figure 1 comprises a base 1, two props 2 and a cap 3.

The props 2 are connected with the base 1 by a conventional method used in powered supports.

The props 2 have part-spherical heads 4 and are connected with the cap 3 (Figures 2, 3) which has part-spherical bearings 5 enveloping the corresponding prop heads 4, and plates 6 (Figure 1) which are secured to the cap by the conventional method employed in powered supports.

The cap 3 and the base 1 may have any structural form used in similar support units.

The support unit comprises also flexible members acting between the cap 3 and the props 2. Each flexible member, according to the invention, consists of two plates 7 arranged in the cap 3 symmetrically with respect to the longitudinal axis of the unit.

The joint between the cap 3 and the head 4 of each prop 2 comprises a part-spherical element 8 located between the plates 7 and the head 4 of the prop 2. The radius R of the sphere of the element 8 is equal to the radius R of the sphere of the head 4 of the prop 2. The element 8 has projections 9 which bear against the plates 7 and projections 10 located between the plates 7.

Each projection 9 bearing against a plate 7 has edges 11 (Figure 3) which are at an angle a to the plate 7 in a plane parallel to the vertical plane passing through the longitudinal axis of the unit.

This shape for the projections 9 allows the cap 3 to turn easily in the vertical plane containing the longitudinal axis of the unit.

The projections 10 located between the plates 7 limit rotation of the element 8 about its vertical axis.

The head 4 of the prop 2 and the part-spherical element 8 have conically tapered surfaces 12 and 13, respectively, facing each other. The generating lines of these surfaces 12 and 13 line on the radius R of the sphere of the element 8 and of the prop head 4.

As the props 2 are relieved and the support unit advances, the cap 3 tends to turn in the vertical plane perpendicuiar to the longitudinal axis of the support unit, the cap resting on the spherical heads 4 of the props 2 through the spherical bearings 5.

The lateral tilting of the cap 3 is restricted by the plates 7 located on the sides of the cap which tip upwardly, these plates acting on the heads 4 of the props 2 through projections 9 which engage the plates and surfaces 13 of the elements 1 8 which engage the confronting surfaces 12 of the heads 4. The cap 3, via the plates 6 and plates 7 bears against the projection 9 of the element 8 which is in abutment with the head. This stabilizes the position of the cap 3 relative to the props 2. The angular position of the cap 3 in the vertical plane passing through the longitudinal axis of the support unit depends on the extension of the props 2.

As the props 2 are extended to a preset height, the cap 3 can turn readily with respect to each prop in the vertical plane passing through the longitudinal axis of the support unit due to the inclined edges 11 of the projections 9 of each spherical element 8.

During relative movement between the props 2 and cap 3 the projections 9 of the elements 8 remain in a predetermined angular position relative to the plates 7 due to the projections 10 which are engaged between the plates 7 and keep the elements 8 from turning about their vertical axis.

The described support unit makes it possible to minimize the dimensions of the support in the retracted condition, to increase its hydraulic extensibility factor while at the same time stabilizing the position of the cap relative to the props.

Claims

1. A powered support device comprising a base, two extensible props mounted on the base and having part-spherical heads, a cap carried on the props by part-spherical bearings in which the prop heads are received, resilient means acting between the props and cap for restricting angular displacement of the cap relative to the props, and a part-spherical element with a radius substantially equal to that of the prop heads located between each prop head and said flexible means for transmitting forces therebetween.

2. A device according to claim 1, wherein the resilient means comprises a pair of plates located symmetrically on opposite sides of a vertical plane containing the axes of the props, and each part-spherical element includes projections for bearing against the plates and projections engaged between the plates to prevent rotation of the element about the prop axis.

3. A device according to claim 2, wherein each projection for bearing against a plate has opposed edges inclined to the plane of the plate at a predetermined angle as seen in a plane parallel to the vertical plane passing through the longitudinal axis of the unit.

4. A device according to claim 1, 2 or 3, wherein each prop head and the element associated therewith have coaxial, conically confronting surfaces, the generating lines of said surfaces lying on a radius of the element and a radius of the prop head respectively.

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