GB2063967A

GB2063967A - Racks for rack and pinion drives for mining machines

Info

Publication number: GB2063967A
Application number: GB8037609A
Authority: GB
Original assignee: Gebr Eickhoff Maschinenfabrik u Eisengiesserei GmbH
Current assignee: Gebr Eickhoff Maschinenfabrik u Eisengiesserei GmbH
Priority date: 1979-11-24
Filing date: 1980-11-24
Publication date: 1981-06-10
Also published as: DE2947514A1; DE2947514C2; GB2063967B

Abstract

A rack section for the rack of a mining machine has a body (2) from which project lugs (5) which are symmetrical both vertically and horizontally and which receive the toothed rims of driving wheels (16). The rack section is mounted by means of a tongue (11) provided with a projecting portion having a bore (12) to receive a mounting bolt. The tongue (11) fits into a rectangular vertical recess (9) and is fixed by a pin (14) passing through aligned portions which lie in the plane of symmetry of the body (2). Thus the rack body (2) may have its attitude changed by being reversed end to end or inverted so that unworn portions of the lugs (5) can be used. <IMAGE>

Description

SPECIFICATION Racks for mining machines The invention relates to racks for mining machines. These are commonly composed of individual sections linked together in a flexible manner, such that their adjacent ends are mounted on a common stay. Flexible connection of a rack section to the stay by a bolt enables the rack sections to be longitudinally movable in a limited way. Lugs which are arranged on both sides of the rack sections at equal spacings from each other are engaged by teeth of two toothed rims of the driving wheel of a winch of the mining machine, which rims laterally envelop the rack.

In rough underground working and with the high tractive force which has to be transmitted to the mining machine, racks are subject to varying degrees of wear. This wear occurs mainiy at the points where the toothing of the driving wheel is in contact with the rack toothing, and above all on parts of the circumference of the pinions or on the flank sections of the toothing against which the tooth flanks of the driving wheel rest.

It is an object of this invention to provide a rack section which can be adjusted to account for wear so as to prolong the useful life thereof.

Accordingly, this invention provides a rack section, for the rack of a mining machine, comprising a rack body from which project lugs to be engaged by teeth of a winch driving wheel, the lugs being designed as pinions or possessing involuted flanks which run from the centre of the lug symmetrically upwards and downards, and also being rigidly connected to the rack body and arranged symmetrically to the horizontal plane of symmetry of the rack, the rack body having a roughly rectangular cross-section with arched top and bottom surfaces, and wherein each end of the rack body incorporates a recess extending over its entire height, the recess having at least one bore which runs at right angles to it, extends over the width of the rack and is located in the horizontal plane of symmetry of the rack.

The recess provides a housing for a mounting member so that the rack section can be detached from the mounting member and moved into a new attitude. In the preferred arrangement the recess houses a tongue having a projecting portion which acts as a mounting member for the rack section, the tongue being removably held in the recess by a pin passing through said bore and an aligned bore in the tonque.

After heavy wear, a rack section which is constructed in this way can be turned not only through 1800 over its entire length and be further used with its inderside lying uppermost, but also end to end through 1 800, to displace particularly badly worn sections, so that further use is made of each rack section independently of the adjacent sections. Conventional racks, because they are integral with the components which hold them, do not allow for further use to be made of them in an arrangement which is turned through 1 800 allowing the bottom half of the circumference of the rack toothing to be used as well for the teeth of the driving wheel to engage.

In the preferred embodiment, the lugs are arranged on both sides at an equal spacing from each other and between which are engaged the teeth of the two toothed rims of the driving wheel of the winch, which rims laterally envelop the rack.

Ideally, with this arrangement, there is provided, between the toothed rims of the driving wheel which envelop the rack laterally, a shaft whose circumference is formed with a hollow groove by means of which the driving wheel is supported against the top surface of the rack body. As a result, this driving wheel not only transmits a part of the weight of the machine to the rack and guides the machine in its movement on a longwall conveyor, but ensures through this that the teeth engage.

In order to prevent sliding movements between the rack body and the shaft of the driving wheel which is supported against it, it is advantageous to provide that the driving wheel supported against the rack body has a bush between its two toothed rims which is rotatably mounted on the shaft of the driving wheel and provides the groove which fits the arch of the rack body. With variations in diameter between the shaft and the pitch line of the toothed rims, differences in speeds of rotation leading to a sliding motion of the shaft which is rotating at the lower speed of rotation can be avoided.

The invention also extends to a rack for a mining machine composed of individual rack sections as hereinbefore defined, linked together such that their adjacent ends are mounted on a common stay, in a flexible manner by a bolt enabling longitudinal movement in a limited way.

The invention may be performed in various ways and one preferred embodiment will now be described with reference to the accompanying drawing which shows the embodiment in a perspective view.

The drawing illustrates a rack section 1 which is constructed as a single part. The body 2 of the rack has a roughly rectangular cross-section with arched top and bottom surfaces 3 and 4. Lugs 5 are arranged on both sides of and symmetrically to the horizontal plane of symmetry of the rack body 2. These lugs 5 are rigidly connected to the rack body 2 and are designed as pinions or are provided with involuted flanks 6 which run symmetrically upwards and downwards from the centre of the lug. The shaping corresponds to one tooth of a toothed wheel with involuted toothing running symmetrically upwards and downwards from the horizontal plane of symmetry of the rack body 2. The lugs 5 extend vertically across only part of the two lateral surfaces 7 of the rack body 2.In the region of each of two spherically capshaped ends 8 of the rack body 2 there is a rectangular recess 9 which runs through the entire height of the rack body 2. A bore 10 runs along the horizontal plane of symmetry at right angles to this recess 9, between the centres of two lugs 5.

The bore 10 extends across the entire width of the rack body 2. In each of the two recesses 9 of the rack body 2 there is housed a tongue 11 having a projecting portion provided with a bore 12, by means of which tongue the rack body 2 is fastened to a support on the carrying equipment, for example, a side bracket. On a level with the bore 10 of the rack body 2 the tongue 11 also has a corresponding bore 13, into which a heavy clamp collar 14 is inserted. Below the rack body 2 the tongue 11 has two lateral lug surfaces 18 which limit the depth to which it is inserted, and which support the weight of the machine and transmit it via a bolt (not shown) to the support of the carrying equipment.

The rack is sandwiched by a driving wheel 1 6 provided with two toothed rims 1 5 which are connected together by a shaft 17 on which a concavely designed bush 19 is rotatably fixed between the toothed rims 15. The driving wheel is supported between the two toothed rims 15, by means of this bush 19, against the arched top surface 3 of the rack, which also acts as a trackwayforthe associated mining machine.

It is also possible, however, to equip a mining machine with a driving wheel 1 6 which has only one toothed rim 15. In this case the life of the individual rack sections 1 or the rack is considerably increased, because they can be used in a position which is turned through 1800, when one side becomes worn.

Claims

1. A rack section, for the rack of a mining machine, comprising a rack body from which project lugs to be engaged by teeth of a winch driving wheel, the lugs being designed as pinions or possessing involuted flanks which run from the centre of the lug symmetrically upwards and downwards, and also being rigidly connected to the rack body and arranged symmetrically to the horizontal plane of symmetry of the rack, the rack body having a roughly rectangular cross-section with arched top and bottom surfaces, and wherein each end of the rack body incorporates a recess extending over its entire height, the recess having at least one bore which runs at right angles to it, extends over the width of the rack and is located in the horizontal plane of symmetry of the track.

2. A rack section according to claim 1, wherein the lugs are arranged on both sides at an equal spacing from each other and between which are engaged the teeth of the two toothed rims of the driving wheel of the winch, which rims laterally envelop the rack.

3. A rack section according to claim 2, wherein there is provided, between the toothed rims of the driving wheel which envelop the rack laterally, a shaft whose circumference is formed with a hollow groove by means of which the driving wheel is supported against the top surface of the rack body.

4. A rack section according to claim 3, wherein the driving wheel which is supported against the rack body has a bush between its two toothed rims which is rotatably mounted on the shaft of the driving wheel and which provides the groove which fits the arch of the rack body.

5. A rack section according to any one of claims 1 to 4, wherein said recess houses a tongue having a projecting portion which acts as a mounting member for the rack section, the tongue being removably held in the recess by a pin passing through said bore and an aligned bore in the tongue.

6. A rack section for the rack of a mining machine substantially as herein described with reference to the accompanying drawings.

7. A rack for a mining machine which is composed of individual sections as defined in any one of claims 1 to 6, linked together such that their adjacent ends are mounted on a common stay, in a flexible manner by a bolt enabling longitudinal movement in a limited way.