GB2127794A

GB2127794A - Skips

Info

Publication number: GB2127794A
Application number: GB08321515A
Authority: GB
Inventors: Plessis Gysbert Jacobus Du; Robert Richard Lindeque; Robert Montaque Joubert
Original assignee: Rotaque Pty Ltd
Current assignee: Rotaque Pty Ltd
Priority date: 1982-09-28
Filing date: 1983-08-10
Publication date: 1984-04-18
Also published as: AU558919B2; GB8321515D0; AU1814583A; ZW18283A1; GB2127794B; ES525952A0; CA1256051A; ES8406976A1

Abstract

The present invention relates to a skip to be suspended in a mine shaft and having a body (18) defining a normally downwardly extending storage chamber (28). A discharge opening is defined in the body, and a door is provided for closing the discharge opening, the door being openable to allow material to be discharged from the chamber. In order to make it possible to reduce the reinforcing required, compared with earlier skips, at least a substantial part of the height of the chamber is of generally circular-cross section and has a cross-sectional area which increases downwardly so that the storage chamber (28) widens downwardly within the body. In addition, it may be provided with deflectors (30) in the form of annular rings welded inside the wall to guide falling material away from the chamber wall to reduce wear on the wall. <IMAGE>

Description

SPECIFICATION Skips Square or rectangular cross-sectional bodies have been used extensively in mine skips, such as that in USA Patent 2790569, and required reinforcing in order to maintain their shape and to provide them with adequate strength. This resulted in considerable labour and material costs and required a large number of components for each skip. In addition, the resulting skips were often heavy and were prone to considerable wear.

The combined mass of the skips and their full loads and the momentum gained in their travel resulted in the need for skip housings at the top of shafts to provide for considerable over-run of the relatively rapidly travelling skips, increasing the costs of the housings.

The skip disclosed in UK publication 2104495 (US application 301703) has a body in which the two pairs of opposed walls diverge downwardly so that the storage chamber in the body widens downwardly within the body.

Provision of the downwardly diverging walls and thus of the downwardly widening chamber can help to eliminate wear on side, back and front walls of the body as material moves downwardly within the chamber. However, it has been found that the effectiveness of the downwardly widening chamber can be increased.

Furthermore, the skip of USSN 301703 does not overcome the need for substantial reinforcing of the body and nor does it enable the combined mass of the skip and full load to be significantly reduced.

The present invention therefore aims to provide a skip which, the Applicant believes, will help to alleviate certain of the problems not fully solved by the invention of USSN 301703.

According to the invention, there is provided a skip to be suspended in a mine shaft and comprising a body defining a normally downwardly extending storage chamber, a discharge opening defined in the body, and a door for closing the discharge opening, the door being openable to allow material to be discharged from the chamber, wherein along at least a substantial part of the height of the chamber the chamber is of generally circular cross section with a crosssectional area which increases downwardly so that at least part of the storage chamber widens downwardly within the body.

Because of the part of the body of circular cross-section, the body need not be provided with reinforcing comparable to that required for square or rectangular skip bodies, in which case the mass of the skip can be greatly reduced. In addition, this part of the body may be formed primarily from a single sheet of plate material bent and joined at a single junction, for example by welding, instead of the much greater number of junctions required in prior art skips referred to above.

The height of the chamber may be greater than its greatest horizontal dimension, usually more than double this, measured in the normal operating condition of the skip.

The body may have a peripheral wall encircling said chamber and an integral sloping bottom adjacent to the discharge opening for directing material towards the opening, the sloping bottom extending from a top portion to a bottom portion adjacent to a bottom portion of the discharge opening.

The cross-sectional area of the chamber may preferably increase downwardly along substantially the whole of the height of the chamber above the top portion of the sloping bottom, the provision of the downwardly widening chamber helping to reduce wear on the inside of the wall of the skip as material moves downwardly within the skip. In order to inhibit wear still further, the inside of the peripheral wall of the slip may be provided with deflectors, such as rings, secured to said peripheral wall, for deflecting downwardly moving material inwardly away from the inside of the peripheral wall of the skip. These deflectors are preferably provided at least at the lower part of the inside of the wall of the skip, for example at spaced intervals up at least a fifth of the height of that part of the chamber above the sloping bottom.

The door may be pivotally mounted on said body and locatable beneath part of said chamber for closing the discharge opening, and may be pivotable downwardly for adopting a position defining a chute surface beneath said opening to allow material to be discharged from the chamber and guided away from the opening. The door may be pivotable about an axis adjacent to the bottom portion of said sloping bottom. For example, the door may be connected to the body by suitable trunnions at opposite sides of the door to provide for necessary movement of the door while keeping adjacent edges of the bottom and door in a relationship for substantially preventing passage of material between the surfaces at the junction.

Any suitable means may be provided for holding the door of the skip normally in a closed condition, and an over-centre arrangement is particularly suitable for this purpose. In one embodiment, the skip may have over-centre mechanisms at opposite sides of the body and these mechanisms may be operable to open and close the door. The mechanisms may be movable to an over-centre condition releasably to lock the door in its closed condition and may be arranged so that the load on the door, the weight of the door itself, and possibly the weight of any operating means provided for operating the door may be used to bias the mechanisms to remain in this locked, over-centre condition.

Each mechanism may, for example, include an arm pivotally connected to the door, a lever having one region pivotally connected to the body and one region pivotally connected to the arm, and a follower connected to the lever and movable by a cam track in a predetermined direction to move the arm and release the respective mechanism from its locked over-centre condition, enabling the door to move to its open position.

Each over-centre mechanism may be such that a line extending between the axes of the pivotal connections of the arm to the door and of the arm to the lever is on one side of the pivot axis of the lever when the mechanism is in its over-centre condition and on the opposite side of that axis when the mechanism is in its open condition. Any reaction forces applied to the lever from the closed door the mechanism such a line and will serve to retain the mechanism in its over-centre condition until the arm is pivoted.

Material is normally discharged into the skip from a loading flask, and such loading flasks often direct material from the feed side of the skip towards the opposite side of the skip, which can result in undue wear on the inside of the wall at the opposite side of the skip. In order to help reduce this wear, the inside wall at the opposite side of the skip can be provided with a wearresistant liner at least at the location where the wear is otherwise likely to be most pronounced.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying schematic drawings, in which Figure 1 is a partial view of a skip in a job's bridle; Figure 2 is a partial side view showing the closed skip and bridle; Figure 3 is a view of the lower part of the skip in its open condition; Figure 4 is a section through the lower part of the skip; Figure 5 is a section through a door mounting trunnion; Figure 6 is a cross-sectional plan view on line VI--VI of Figure 2; and Figure 7 is a side view of a cam track for operating the skip.

Referring to the drawings in more detail, a skip 10 is mounted in a job's bridle 12 on pivot shafts 14 and is prevented from swinging within the bridle by means of locks 1 6. The bridle may be of: a conventional construction and may be capable of receiving a mancage in place of the skip.

The bridle has suitable guides (not shown) for co-operating with a guide assembly in'a mine shaft to guide the bridle for movement in a vertical direction.

The skip has a body 1 8 comprising an annular peripheral wall 20 defined about a substantially central vertical axis of the skip and of substantially circular cross-section, in plan view, along the major part of its height, an upper curved wall 22, and upper side walls 24. At its upper end, the body is provided with a feed opening 26 between the side walls 24 for receiving material from a loading flask and a feeder chute.

The annular wall 20 encircles and substantially defines a storage chamber 28 of generally circular cross-section and the cross-sectional area of this chamber increases downwardly over a height of, for example, about 4500 mm from the top of the chamber, which is just below the feed opening 26 and at which the chamber has a diameter of, for example, about 1200 mm, to a level immediately above the top portion of a sloping bottom 32 of the body 1 8, the diameter of the chamber at this level being about 1300 mm, for example. Annular rings 30 (Figure 2) are welded to the inside surface of the annular wall 20 up the lower part of the height of that part of the chamber above the bottom 32 over a distance of at least 1000 mm.

These rings may be spaced at suitable distances of, for example, from 10 to 300 mm apart and may serve as deflectors for deflecting downwardly moving material inwardly away from the inside of the wall 22 of the skip to reduce wear of the walls at the lower part of the skip.

Because the wall 20 is of circular crosssection, external reinforcing ribs at uniformly spaced distances up the outside of the wall 20 are not necessary. The absence of such ribs assists in enabling the mass of the skip to be reduced when compared with rectangular skips of similar loadcarrying capabilities.

The bottom of the skip is partially closed by the sloping bottom 32, which is semi-elliptical and which is inclined downwardly at a suitable angle with respect to the central vertical axis of the skip and extends over approximately half of the area of the bottom of the skip. A discharge opening 34 is defined between a bottom portion of the sloping bottom 36 substantially intersecting said axis and part of the wall 20 of the body and is normally closed by a door 38. The door and body can be provided with wear plates 40 in a suitable manner.

The door 38 is pivotally mounted on trunnions 42 (shown in Figures 4 and 5). Each of these trunnions is formed partly by a respective end of a rigid rod 44 of substantially square cross-section along the major part of its length. The ends 46 of the rod are rounded and lock washers 48 are fitted onto the ends of the rod and trap bearings 50 in position. Each bearing 50 is received within a bearing housing 52 provided with a cover plate 54. A spacer 56 is provided on the rod between the square part of the rod and the respective bearing 50 and a labyrinth seal 58 is formed between the spacer 56 and the bearing housing 52.

The square part of the rod 44 is welded to ribs 60 spaced along the bottom 36 of the skip and mounting plates 62 are fixed rigidly to the bearing housing 52 at each side of the skip. The door 38 is fixed rigidly to the mounting plates 62 at a position such that it is eccentrically mounted with respect to the axis of rotation 64 of the trunnion.

The mounting of the door is such that, in the closed condition of the door shown in Figure 4, the wear plate 40 of the door presses against the lower edge of the bottom 36 of the skip.

However, as the door is pivoted in the direction of arrow 66 in Figure 4, the door moves away from the lower edge of the bottom 36 and swings through an arc about the axis 64 until it reaches a position shown in Figure 3 where it is aimost parallel to the bottom 36 with its upper end below the level of the lower part of the bottom 36. In this position, the bottom and door form a chute for guiding material flowing from the skip.

The door is provided with side plates 68 to further improve the guiding of the material.

The skip shown has shock pads of suitable rubber between the wear plates 40 and lower plates 72 of the bottom 36 and door 38. These assist in avoiding the 'nut cracker' effect that sometimes arises when doors close in a manner similar to that illustrated. However, if it is considered that a 'nut cracker' effect is likely to arise when the door of the skip shown is closed, it is possible to provide the bottom 36 of the hopper with a wedge-like formation which tapers to a point at the lower part of the plate 72 of the bottom 36. This arrangement can result in particles that would normally be subject to a 'nut cracker' action being squeezed out from between the bottom 36 and the door 38 as the door closes.

The door of the skip shown is normally held in its closed condition by a door control means including over-centre mechanisms 74 at opposite sides of the body 1 8. Each such mechanism includes a follower 76 in the form of a tipping wheel, an arm 78 pivotally connected to a respective pivot 80 on the door and a lever 82 pivotally connected to a mounting 84 on the body 1 8 of the skip by a pivot 86. The mounting 84 may be a relatively simple member welded to the wall 20, and may be of any suitable shape, as shown in Figures 2 and 6.

The end of each lever 82 furthest from the respective pivot 86 is provided with a pivot 88 connecting to the free end of the arm 78, the follower 76 being located on the lever 82 between the pivots 86 and 88.

As shown in Figure 2, each arm 78 is cranked so that, with the door in its normal closed condition, it rests against a supporting shaft of the follower 76 in a locked over-centre condition.

If required, guides may be provided on the body for guiding the arm to move to this position. The arm is cranked to such an extent that an imaginary line 90 passing through the axes of the pivots 80 and 88 is on one side of the axis of the pivot 86 when the door is in its closed condition and moves to the opposite side of the axis of the pivot 86 when the door is moving to its open condition. Thus, when the door is in the position shown in Figure 2, forces applied to the closed door by a load in the skip, and the weight of the door itself, serve to provide a reaction force along the imaginary line and increase the locking effect of the mechanisms. The door is opened by causing each follower 76 to follow a path such as the path 92 of Figure 3 as the skip moves upwardly into the head gear of a mine.

In order to cause the followers 76 to follow such a path, the skip is used with a skip head which includes cam tracks 96 and 98 arranged on opposite sides of the skip head and facing towards one another for receiving the followers 76 of the respective over-centre mechanism.

When the skip moves upwardly into the skip head, the followers 76 move upwardly between the respective cam tracks 96 and 98 in the direction of arrow 100 and are guided between the cam tracks, the cam tracks 98 forcing the followers to move the mechanisms 74 from their over-centre locked condition and the cam tracks 96 supporting the followers 76 to prevent excessively rapid opening of the door 38 once the mechanisms have moved from the over-centre condition. The tracks 96 support the followers 76 until the door 38 is fully open.

When the skip is again moved downwardly, the cam tracks 96 force the followers 76 to move in the opposite direction and, in due course, force the mechanisms 74 to return to the over-centre condition so that the door 38 is again locked.

Although the downwardly diverging shape of the skip and the rings 30 can assist in reducing undue wear of the annular wall 20 of the skip, it may be found that material flowing into the skip from a loading flask will be projected across the width of the skip and strike the inside wall surface of the skip at the side of the skip facing the feed opening but usually below the level of the feed opening 26. In order to inhibit undue wear as a result of this, a wear-resistant liner 102 may be bonded to the inside of the wall of the skip where the wear resulting from flow of material into the skip would otherwise be most pronounced.

Claims

1. A skip to be suspended in a mine shaft and comprising a body defining a normally downwardly extending storage chamber, a discharge opening defined in the body, and a door for closing the discharge opening, the door being openable to allow material to be discharged from the chamber, wherein along at least a substantial part of the height of the chamber the chamber is of generally circular-cross section with a crosssectional area which increases downwardly so that at least part of the storage chamber widens downwardly within the body.

2. A skip according to Claim 1 , wherein the height of the chamber is greater than its greatest horizontal dimension measured in the normal operating condition of the skip.

3. A skip according to Claim 2, wherein the height is more than double the greatest horizontal dimension.

4. A skip according to Claim 1, 2 or 3, wherein the body has a peripheral wall encircling said chamber and an integral sloping bottom adjacent to the discharge opening for directing material towards the opening, the sloping bottom extending from a top portion to a bottom portion adjacent to a bottom portion of the discharge opening.

5. A skip according to Claim 4, wherein the cross-sectional area of the chamber increases downwardly along substantially the whole of the height of the chamber above the top portion of the sloping bottom.

6. A skip according to Claim 4 or 5, wherein the inside of the peripheral wall of the skip is provided with deflectors secured to said peripheral wall, for deflecting downwardly moving material inwardly away from the inside of the peripheral wall of the skip.

7. A skip according to any preceding claim, wherein the door is pivotally mounted on said body and locatable beneath part of said chamber for closing the discharge opening, and is pivotable downwardly for adopting a position defining a chute surface beneath said opening to allow material to be discharged from the chamber and guided away from the opening.

8. A skip according to Claim 7, wherein the door is connected to the body by suitable trunnions at opposite sides of the door to provide for necessary movement of the door while keeping adjacent edges of the bottom and door in a relationship for substantially preventing passage of material between the surfaces at the junction.

9. A skip according to Claim 7 or 8, having over-centre mechanisms at opposite sides of the body and movable to an over-centre condition releasably to lock the door in its closed condition and arranged so that a load on the door and the weight of the door itself bias the mechanisms to remain in this locked, over-centre condition.

1 0. A skip according to Claim 9, wherein each mechanism includes an arm pivotally connected to the door, a lever having one region pivotally connected to the body and one region pivotally connected to the arm, and a follower connected to the lever and movable by a cam track in a predetermined direction to move the arm and release the respective mechanism from its locked over-centre condition, enabling the door to move to its open position.

11. A skip according to any preceding claim, which has a feed side into which material can be directed, and an opposite side facing the feed side and provided with a wear-resistant liner.

1 2. A skip substantially as herein described with reference to the accompanying drawings.