GB2098255A

GB2098255A - Mechanical connecting device between head or foot of a prop and the cap or base of roof supports

Info

Publication number: GB2098255A
Application number: GB8211672A
Authority: GB
Original assignee: ALSACE MINES POTASSE
Current assignee: ALSACE MINES POTASSE
Priority date: 1981-05-12
Filing date: 1982-04-22
Publication date: 1982-11-17
Also published as: ATA172282A; AT377058B; GB2098255B; MA19467A1; FR2505925B1; FR2505925A1; BR8201700A; DE3212839A1

Abstract

The device comprises a pivot pin (4) which extends through the head of the prop (3) and has at each end a flat (5) which is adapted to bear against a plane surface of a holding member (6) integral with a cap or base (1). The pivot pin is locked in place by means of two stirrups (7) fixed by pin elements in holes 8 to the holding members (6). This provides a compact connection located within the cap or base, the flats (5) providing for ease of location of the pin. <IMAGE>

Description

SPECIFICATION Mechanical connecting device between the head or foot of a prop and cap or base of roof supports The present invention relates to a mechanical connecting device between the head or foot of a prop and the base or cap of roof supports.

It is known that roof supports used in mines or public works comprise a base placed against a first wall, more particularly the floor, and a cap applied against a second wall, more particularly the roof, and one or more props connected to the base and to the cap.

The caps and bases of roof supports generally are fixed on substantially hemispherical prop heads, ensuring good transmission of forces between the props and the caps or bases which bear, for example, respectively on roof or floor, and at the same time allowing the necessary mobility for the caps relative to the props when movements occur in the supported rock or other ground.

When the supports are not in position between the walls, the cap or base is no longer in contact with a wall, and it is necessary to provide, for example between the cap and the prop, a mechanical connecting device which on the one hand prevents the cap from sliding off the hemispherical head of the prop and falling, whilst still allowing it to pivot within certain limits, and on the other hand allows the withdrawal of the cap at the hydraulic telescoping of the prop.

Many mechanical devices between the head or the foot of a prop and the cap or the base of the corresponding roof support have been proposed.

More particularly there have been proposed many devices which allow the ends of the props to be imbedded in the interior of lining elements which constitute the base on the one hand and the cap on the other. By imbedding the ends of the props in the lining elements the closed height of the corresponding roof support is reduced.

A known connecting method uses pivot pins of great length extending through the heads of the props through a funnel-shaped aperture, then through the cap lining part, these pivot pins being fixed outside the lining; but these pivot pins of considerable length tend to bend and consequently become difficult to remove.

According to another connecting system which is known, cables are used which also extend through the lining and are fixed at the outside thereof.

These cables are excessively flexible. This flexibility is on the one hand detrimental to the connection between the props and the lining and on the other hand causes wear on, and so deterioration of, the said cables by friction.

A device has also been proposed which allows the pivot pin to be fixed within the lining, which avoids the need for holes in the lining which weaken it. This device comprises a pivot pin which is engaged at each end between two perforated holding members fast with the cap, and which rests at each end on the anchoring pin extending through the two holding members at the same time. To reduce the height of the perforated holding members of the connecting device and to create a line of contact with each of the anchoring pins, it has been proposed to use a pivot pin comprising a flat portion, the pivot pin resting by its flat portion on the anchoring pin.This device has a certain number of disadvantages: on the one hand the production of the perforated holding member lining elements is difficult, and on the other hand during positioning the pivot pin has to be presented correctly between each of the two pairs of members otherwise there is a risk that the holding members, which are very fragile, will be deformed.

The present invention provides a mechanical connecting device between the head or the foot of a prop and the cap or the base of a corresponding roof support, which device comprises a pivot pin provided with flats at each of its ends and extending through an aperture in the head or the foot of the prop, the aperture preferably having a trumpet shape, the device being iocated internally of the lining characterised in that the device comprises at each end of the pivot pin a holding member which is fast with the lining and has a plane surface and a stirrup connected to each corresponding holding member by a pin element which extends through said holding member, the flat of the pivot pin coming to bear against the plane surface of the holding member which is fast with the lining, and the cylindrical portion of the pivot pin diametrally opposite from the flat rests on the corresponding stirrup.

The device according to the invention affords many advantages. The two holding members connected to the lining are very strong and may, for example, be formed directly in the mass comprising the spherical dish supporting the prop when this steel cup or dish is produced by casting or stamping.

The pivot pin is positioned by means of flats, which facilitates assembly.

The pivot pin rests on the stirrups, which offer with the cylindrical portion a large contact surface, which obviates deformation of the pivot pin. Thus the overhang of the pivot pin between the central bearing zone of the prop and the stirrups is reduced to a minimum.

The pivot pin is preferably made of steel and will have a diameter such that it withstands the forces involves in hydraulic telescoping. The pin elements holding the stirrups in place are also made so as to resist telescoping forces. On the other hand, the strength of the stirrups is preferably regulated, by suitable choice of their thickness and the material from which they are produced, such that they fracture before there is any deterioration in the pivot pins or the straps, they form the mechanical equivalents of electrical safety fuses, so to speak.

It should be noted that when the roof support is under load the forces are transmitted through the hemispherical head or heads, and that the connecting pivot pins are free in the orifices of the prop heads, during the hydraulic telescoping of the props the pivot pins are subjected to the action of forces.

The invention will be further described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a partially cut away side view of a connecting device connecting a cap and prop according to the invention.

Fig. 2 is a view along the line Il-Il of Fig. 1.

The mechanical connecting device serves to fix a cap (1) to a prop head (3) having a hemispherical end. The cap (1) is provided with a spherical dish (2) which pivotably receives the prop head (3). The prop head (3) has an aperture (11) of "trumpet" shape. A connecting pivot pin (4) extends through the prop head (3) by way of the trumpet-shaped aperture. The connecting pivot pin has a flat (5) at each end. Under the cap (1) two holding members (6) are fixed having a plane surface on their face inside the cap. The flat (5) of the pivot pin (4) bears on this plane surface of the holding member (6) which is fast with the cap (1). The members (6) have a through hole (8) perpendicular to the pin (4). The pivot pin (4) is locked in position by means of two stirrups (7) extending externally of the straps (6) and locked in position by means of pin elements (9) extending through the holes (8).

The pin element (9) is itself held in place by two keys or split pins or the like (10). The connection between the prop and a base may be identical to that described for a prop and a cap.

Claims

1. A mechanical connecting device between the head or the foot of a prop and the cap or the base of a corresponding roof support, comprising a cylindrical pivot pin provided with flats at each of its ends, extending through the head or the foot of the prop through an aperture, which is preferably of trumpet shape, and fixed by a device internal of the support lining, characterised in that the device comprises at each end of the pivot pin a holding member fast with the lining and having a plane surface on the face inside the lining, and a stirrup connected to each holding member by a pin element extending through the latter, the flat of the pivot pin being adapted to bear against the plane surface of the strap and a cylindrical portion of the pivot pin diametrically opposite from the flat resting on the corresponding stirrup.

2. A roof support comprising a prop having a cap and/or a base connected thereto, the connection comprising an aperture in an end of the prop, a pin having a flat at each end and extending through the aperture, holding members located in the cap or base and having flat portions to cooperate with the flats of the pin, and stirrups holding the pin in position against the holding members.

3. A support as claimed in claim 2, wherein the holding members are integral with the cap or base.

4. A support as claimed in claim 2 or 3, wherein the aperture in the end of the prop is divergent towards its ends.

5. A support as claimed in claim 2, 3 or 4, wherein the stirrups are held in place by a pin element passing through legs of the stirrups and a respective holding member.

6. A roof support comprising a prop having a cap and/or base connected thereto substantially as hereinbefore described with reference to Figs. 1 and 2 of the accompanying drawings.

7. The features hereinbefore disclosed or their equivalents in any novel combination.