Title of Invention

"A RIGID STEEL PROP USEFUL FOR SUPPORTED MINE/TUNNEL ROOFS"

Abstract

A rigid steel prop useful for supporting underground mine/tunnel roofs which comprises a bottom tube (1) having a plate (2) at its upper end, an upper tube (3) being fixed on top of the said plate (2), the upper portion of the said upper tube (3) having a horizontal hole in which is fitted a cam-integrated shaft (4) by means of locking rings (5&6), the top end of the said upper tube (3) being provided with a guide ring (8), a tube (9) having a top channel (10) and a bottom plate (7) being fitted telescopically through the said guide ring (9) so that the bottom plate (7) rests on the top of the said cam-integrated shaft (4), the said shaft (4) being provided with a handle (11) having a locking lever (12) fitted onto the outer surface of the upper tube (3), means (13 hook, 14 wire rope & 15 pulley) being provided for remote release of the said locking lever.

Full Text

This invention relates to a rigid steel prop useful for supporting underground mine / tunnel roofs. The release of conventional steel rigid prop is difficult and sometimes impossible when the load on the prop under installation is quite high. Moreover, when the roof condition is adverse and the release/withdrawal of the conventional rigid steel prop is required for its repeated use aiming at the economical utilisation, the release/withdrawal operation from a close vicinity of the installed loaded prop is undoubtedly felt very much unsafe. To the best of our knowledge, the existence of releasing device of rigid prop under high roof load is unknown. However, the problem encountered are : 1) The release of rigid steel prop is difficult and sometimes not possible when the load on propis quite high; 2) When the roof condition is unknown, the releasing of the prop from a close vicinity is unsafe and may cause fetal accident. The main object of the present invention is to provide a rigid steel prop with remote release mechanism. Another object is to provide a device for easy, quick releasing from a remote place which ensures repeated use of the device. Working principle of the device of the present invention is as follows : The releasing mechanisms is incorporated in a steel rigid prop consisting of a long upper tube of relatively lower diameter, a short bottom tube and a steel plate welded in between the two tubes. The releasing mechanism consists of a cam integrated shaft mounted on the upper tube holes located at a convenient position from the top end of the upper tube. The cam integrated shaft is placed on load bearing rings and looking nuts in the holes provided at the upper tube. One end of the shaft is firmly fitted with a handle which can be locked with a swiveling type locking lever fitted with the upper tube. A small pulley is fitted at the lower end of the locking lever for guiding the steel wire rope fixed with a hook which is hooked up with the locking lever. A channel is welded at the top and a steel plate is welded at the bottom of the telescopic tube which is housed within the upper tube of the prop. The steel plate of the telescopic tube is in contact on the cam. The cam is fitted in such a way that load through le telescopic tube acts just at the off set from the centre of the cam inducing a rotatory movement of the shaft along with the locking handle. This induced rotary movement is arrested by the locking lever. When the load on the prop is required to be released, the hook fitted with the wire rope is fastened with the locking lever and the rope is passed over the pulley and is pulled from a safe distance causing the downward movement of the locking lever. Thus, automatic rotation of the handle along with the cam integrated shaft. This movement would lower down the telescopic tube within the upper tube causing the release of the load from the prop. In the drawing accompanying this specification (Fig. 1) shows the sectional elevation of the prop and (Fig. 2 ) show the sectional elevation of the cam. Accordingly, the present invention provides a rigid steel prop with remote release mechanism useful for supporting underground mine/tunnel roofs which comprises a bottom tube (1) having a plate (2) at its upper end, an upper tube (3) being fixed on top of that said plate (2), the upper portion of the said upper tube (3) having a horizontal hole in which is fitted a cam-integrated shaft (4) by means of locking rings (5 &6): the top end of the said upper tube (3) being provided with a guide ring (8), a tube (9) having a top channel (10) and a bottom plate (7) being fitted telescopically through the said guide ring (9) so that the bottom plate (7) rests on the top of the said cam-integrated shaft (4), the said shaft (4) being provided with a handle (11) having a locking lever (12) fitted onto the outer surface of the upper tube (3), means (13 hook, 14 wire rope & 15 pulley) being provided for remote release of the said locking lever. Operation of the device : The releasing device of the rigid steel prop includes a telescopic tube (9) fitted with a channel (10) at the top and a steel plate (7) at the bottom which is in contact on a cam-integrated shaft (4) mounted on the upper tube (3) of the prop by making a hole in it at the appropriate distance from the top. The cam integrated shaft (4) is placed on the load bearing rings (9) welded at the hole of the upper tube (3) and locked by a locking ring (6) to restrict the sideway movement of the cam-integrated shaft (4). One end of the cam-integrated shaft (4) is firmly fixed with a handle (11) which is locked by a locking lever (12) fitted with the upper tube (3). A pulley (15) is fitted below the locking lever (12) with the upper tube (3) at a lower portion from the locking lever (12) for guiding the steel wire rope (14) required for releasing. A guide ring (8) in two halves fitted with the upper tube (3) to guide the telescopic tube (9) and limit its extension within the upper tube (3). When the load comes on the telescopic tube (9), the same is transmitted to the upper tube (3), through the cam-integrated shaft (4). As the top of the cam (4) in reference to the bottom plate (7) of the telescopic tube (9) is in slightly in off-set position from the centre of the cam (4), the load on the prop induces a rotatory motion to the cam-integrated shaft (4). As the handle (11) fixed with the cam-integrated shaft (4) is fastened with the locking lever (12), the induced rotatory motion would prevent the rotation of the cam integrated shaft (4). When it is required to release the loaded prop, the hook (13) fitted with the wire rope (14) is placed on the pulley (15). The wire rope (14) is then pulled from a safe distance which in turn gives a downward movement of the locking lever (12) and releases the locking lever (12), allows the rotation of the cam-integrated shaft (4) and downward movement of the teleseopic tube (9) whichfinally releases the prop load completely. The advantages are: 1. Releasing and withdrawal of installed props under load condition in mine/tunnel roofs for its repeated use resulting in economy. 2. Allows withdrawal of the prop from a remote safe distance offering a high degree of safety for the workers. 3. The remote releasing mechanism will- offer reduction in time and. manpower requirement involved during releasing and withdrawal operation of the prop. We claim; 1. A rigid steel prop useful for supporting underground mine/tunnel roofs which comprises a bottom tube (1) having a plate (2) at its upper end, an upper tube (3) being fixed on top of the said plate (2), the upper portion of the said upper tube (3) having a horizontal hole in which is fitted a cam-integrated shaft (4) by means of locking rings (5 &6), the top end of the said upper tube (3) being provided with a guide ring (8), a tube (9) having a top channel (10) and a bottom plate (7) being fitted telescopically through the said guide ring (9) so that the bottom plate (7) rests on the top of the said cam-integrated shaft (4), the said shaft (4) being provided with a handle (11) having a locking lever (12) fitted onto the outer surface of the upper tube (3), means (13 hook, 14 wire rope & 15 pulley) being provided for remote release of the said locking lever. 2. A rigid steel prop useful for supporting underground mine/tunneI roofs substaitially as herein described with reference to the drawings-accompanying this specification.

Documents:

314-del-1995-abstract.pdf

314-del-1995-claims.pdf

314-del-1995-correspondence-others.pdf

314-del-1995-correspondence-po.pdf

314-del-1995-description (complete).pdf

314-del-1995-drawings.pdf

314-del-1995-form-1.pdf

314-del-1995-form-2.pdf

314-del-1995-form-4.pdf

314-del-1995-form-9.pdf

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