GB2088445A - Winch for Underground Mineral- winning Machines - Google Patents

Abstract

A winch for moving a winning machine lengthwise has at least one driving gear or wheel 16 embodied by two spur gears 15 disposed coaxially of one another and engaging with the toothed rack 11 extending lengthwise of the path travelled by the machine. Extension members or projections 12 are disposed at the same pitch on opposite sides of the rack and each spur gear 15 engages, on a respective side of the rack 16, with its teeth between the extension members 12. The spur gears 15 are independently driven by motors 22 (not shown), via respective gear trains, and can be relatively rotated so that there is equal loading on the gears 15. <IMAGE>

Description

SPECIFICATION Winch for Underground Mineral-Winning Machines The invention relates to a winch for an underground mineral-winning machine having a toothed rack with equally spaced projections on either side thereof, the rack extending lengthwise of the path of travel of the machine.

A feed mechanism for cutter-loaders is known in which the winch of the feed mechanism has a driving gear whose two spur gears engage with a toothed rack disposed on the goaf side of the face conveyor and extending lengthwise of the path travelled by the machine. The rack, in the form of a tubular member, has on both sides partspherical projections which are spaced apart from one another by the same pitch, the two spur gears associated with the driving gear of a winning machine having their teeth meshing between the projections on opposite sides of the toothing rack.

The driving gear is a unitary device and rigidly interconnects the two spur gears. Inaccurate machining in manufacture of the rack parts, and in particular of the projections, and even minor differences of direction between individual rack parts in relation to the direction of machine movement, such as are unavoidable in underground working, always lead to a one-sided loading of the driving gear - i.e., to only one of the two spur gears being loaded; in such cases only the teeth of the spur gear disposed on the outside of a curvilinear rack portion are operative.

Because of the usually rapid feed of the winch, the feed-transmitting teeth of the single operative spur gear experience very heavy stressing when the driving gear is loaded one sidedly, resulting in a considerable shortening of the working life of the driving gear and of damage to the rack parts which are stressed.

It is the object of the invention to provide an improved winch for an underground mineralwinning machine.

From one aspect the invention consists in a winch for an underground mineral-winning machine having a toothed rack with equally spaced projections on either side thereof, the rack extending lengthwise of the path of travel of the machine, including a driving wheel for meshing with the rack constituted by a pair of spur gears disposed coaxially of one another to engage the projections on the rack, the spur gears being relatively rotatable in either sense and means for drivingly connecting each gear to a respective driving motor.

In this winch there is preferably no driving connection between the two spur gears of the driving gear or wheel. The two spur gears can rotate independently of one another in response to an input by their independent driving motor, e.g. an electcce motor, and so their teeth can always engage with the rack projections present in their plane of rotation. Manufacuturing errors affecting the pitch dimension of the projections may thus be overcome. Equally the winch may compensate for variations between the direction of machine movement and rack length and for differences such as arise in curved regions of the face conveyor due to differences between the curve radii of the rack projections on the inside and outside of the curve.

Conveniently, the two driving motors are hydraulic motors which are in hydraulic communication with a common hydraulic pump and are drivingly connected, each by way of reduction gearing, to a respective one of the spur gears. In a winch of this kind, for instance, a driving motor of the winning machine, for example the motor which also drives the shearing or cutting tool, can drive the hydraulic pump.

However, the pump may be driven by a separate winch motor provided solely for this purpose.

Both the motor may be connected in parallel to one another in the hydraulic circuit of a hydraulic pump disposed in the winch casing of the machine and may be supplied by the pump with the hydraulic fluid necessary for their operation.

In one embodiment a collar is disposed between and coaxially of the two spur gears and bears on the toothed rack. This collar, which maintains the separation between the two spur gears and the depth to which the tooth system of the driving wheel or gear penetrates into the rack, enables much of the weight of the machine to be transferred to the rack nd also enables the machine to be guided.

The goaf-side spur gear can be mounted for corotation on a shaft which is drivingly connected to one of the two driving motors, whilst the spur gear near the subframe can be disposed on a collar which is drivingly connected to the other driving motor and rotatably mounted on the shaft.

The two independently rotatable spur gears can then be arranged very compactly, which is particularly advantageous in the case of low winning machines in which the winch output shafts are directly connected to their associated spur gears.

From another aspect the invention consists in a winch for an underground mineral-winning machine having a toothed track with equally spaced projections on either side thereof, the rack extending lengthwise of the path of travel of the machine, including a driving wheel for meshing with the rack constituted by a pair of spur gears disposed coaxially of one another to engage the projections on the rack, and a drive shaft, the spur gears being resiliently mounted in their plane of rotation on the drive shaft.

Disposing the spur gears resiliently in both directions of driving-wheel rotation enables the two spur gears to rotate relatively to one another to an extent sufficient to compensats for pitch inaccurate of the tooth systems on either side of the rack and for both spur gears to share the load.

To this end, the two spur gears may be mounted either individually or in common on a hub which corotates with the drive shaft. The spur gears having radial projections, in the peripheral surface of their bore which extends centrally around the hub, and the hub having further radial projections on that part of its peripheral portion which is enclosed by the bore. Ths radial projections engage in one another. Resilient elements are disposed between the projections on the gears and the projections on the hub. The resilient elements allow the spur gears sufficient mobility, in the peripheral direction of the driving wheel to participate in the transmission of forces.

Preferably, the resilient elements are compression springs centred in bores in the projections. Springs of this kind transmit very substantial forces satisfactorily and enable the spur gears which they resiliently retain, in the peripheral direction, to move sufficiently in relation to the hub or hubs mounted on the drive shaft.

The invention may be performed in various ways specific embodiments of which will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view showing part of a winning machine; Figure 2 is a diagrammatic view of the winch drive of the winning machine; Figure 3 is a partly sectioned view of another embodiment of the invention; Figure 4 is a front view in half-section of the spur gears of a further emebodiment of the invention; and Figure 5 is a side view of the spur gears of Figure 4.

A mineral-winning machine 1 comprises a number of constructional units which are screwed fast to one another and to a machine frame (not shown). The units are disposed above a face conveyor 2 and form subframe 3. A support or carrying arm 5, carrying a shearer drum 6, is secured to a rib 4 which projects from the subframe 3. The arm 5 can rotate around a pivot shaft which extends parallel to the floor and perpendicularly to the mineral face. A drum 6 is connected to a driving motor 7 by way of reduction gearing disposed inside arm 5. The motor 7 is flanged mounted on the arm 5 and driving it. The arm 5 and the motor 7 are retained by a common pin 8 which extends through an appropriate bore in rib 4 such that its axis extends parallel to the floor.A clearing plough 10 for facilitating the discharge of debris from the back of the cut to the face conveyor 2, is secured to a two-element holder 9 to be pivotable around the shearer drum pivot and to be adjustable vertically with the drum 6.

The feeding or advancing movement for the machine 1 is produced utilizing a toothed rack 11, which extends lengthwise of the path travelled by the machine. The rack 11 has on each side extension members or projections 12 which are spaced apart from one another at the same pitch to form the tooth systems. Two output gears 13 are mounted on two parallel output shafts 14 of the unit of subframe 3 to engage with a respective one of two spur gears 1 5 of a driving wheel 1 6 of the machine 1. The two gears 1 5 are disposed on opposite sides of the rack body or frame 1 7 and mesh with the members 12 below.

The wheel 1 6 which, in co-operation with the rack 11, converts the motion of the two wheels 1 3 into a feeding motion, is embodied by the two spur gears 1 5 and, disposed therebetween, a collar 1 8 having a concave peripheral surface. The collar 18 and the two spur gears 15 on either side thereof are mounted for independent rotation on a common pin 1 9; the main function of the collar 1 8 being to maintain the spacing between the spur gears 1 5 and to limit the depth to which the teeth of the gears 1 5 engage between the members 12 of the rack 11. Retaining members 20 connect the rack 11 , which is disposed on the goaf-side adjacent the face conveyor 2, to the side wall of the face conveyor.A skid or runner or the like 21, visible in Figure 3, is provided to ensure that the spur gears 1 5 mesh with the rack 11. The skid 21 is disposed very near to the wheel 1 6 where it engages below the rack 11 and guides the machine 1.

As can be seen from Figure 2, a respective hydraulic motor 22, for each output gear 13 is connected via reduction gearing 23 and a clutch 24, to a respective planetary transmission 25 whose sun wheel 26 transmits the rotation of the motor 22 to its associated gear 13. The two motors 22 communicate via a common hydraulic circuit with a common hydraulic pump 27, which is driven by a motor 28 disposed in an adjacent unit. The motor 28 drives, via gears 29, a flushing pump 30 which is disposed inside the unit and which continuously replaces some of the hydraulic fluid of the hydraulic circuit by filtered and cooled fluid.Since each of the two relatively rotatable spur gears 1 5 is driven by its own motor 22, they can rotate independently of one another and can therefore compensate for inaccuracies of pitch, more particularly at the junctions between the rack extension members. Consequently, the flanks of the teeth of both gears 15 are always in engagement with one of the members 1 2 and the gears 1 5 share the load uniformly.

The embodiment shown in Figure 3 is particularly suitable for low machines. In this construction a spur gear 31, on the goaf-side, corotates with a aft 32 which is coupled in a winch casing 33 with an independent driving motor and whose end is borne in side wall 34 of casing 35 of the drive wheel. A collar 37, which carries the adjacent spur gear 36, bears on the shaft 32 and is rotatably mounted thereon. The collar is connected, inside caseing 33, to a second independent driving motor. As in the previous case the two spur gears 31, 36 are disposed one on either side of a concave collar 38 which is mounted for rotation on the shaft 32. The collar 38 rolls on the rack 11 below it and limits the depth of tooth engagement. A skid or runner, or the like, 21 is also disposed on shaft 32 to below the goaf-side extension members 12 of the rack 11 and thus ensures the meshing of the spur gears 31,36. Pivoting the runner 21 is limited by an abutment 39, which is welded to the inside edge of side wall 34 of drive wheel casing or covering 35 to prevent the runner 21 from jamming with the rack 11 in operation. Horizontal movement of the runner 21 is limited by a spacer disc 40 disposed between the goaf-side spur gear 31 and the runner 21.

Figure 4 shows another embodiment of the invention in which two spur gears 41 of a driving wheel 42 are mounted on a common drive shaft 43 and are disposed one on either side of a coaxial collar 44 which has a concave periphery rolling on the body or frame 1 7 or rack 11. The collar 44 is carried by a spacer collar 45 which extends around shaft 43 and locates hubs 47, which are so secured to the shaft 43, to corotate therewith, by a tongued and grooved connection 46. As can be seen from Figure 5, the spur gears 41 are engaged on the hub 27 by way of radial projections 48, formed on the gears 41, which engage between radial projections 49 formed on the hub 47. The projections 48 project into the bore of their respective gears, whilst projections 49 extend outwardly from those parts of the hub 47, which are enclosed by gears 41.A clearance 50 is provided, between the sealing projections 48 and 49, of sufficient dimension to permit rotation of approximately 100 between the hub 47 and the spur gear 41. Conical compression springs 51, which are disposed in opposed blind bores 52 in the hub projections 49 and which engage, at the end projecting from the bore 52, with side surfaces 53 of the spur gear projections 48, transmit the driving torque of the driving shaft 43 from the hub 47 to the spur gear 41. They retain the latter peripherally with a resilience such that the two spur gears 41 always have their teeth meshing with the rack extension members 1 2 and receive substantially equal proportions of the load. Axial movements of the gears 41 are prevented by discs 54 on the outside of the hubs 47 and of the spur gears 41.

It will be appreciated that the collar between the spur gears can be omitted in any of these embodiments and that the two spur gears may be disposed immediately adjacent one another for rotation relatively to one another. This arrangement is particularly advantageous for use with wide toothed racks having a tooth system disposed between lateral ledges or strips or the like. The two spur gears bear on these particularly wide teeth, e.g. pin teeth, over at least some of their width and improve the transmission of forces.

Claims (10)

Claims

1. A winch for an underground mineral winning machine having a toothed rack with equally spaced projections on either side thereof, the rack extending lengthwise of the path of the machine, including a driving wheel for meshing with the rack constituted by a pair of spur gears disposed co-axially of one another to engage the projections on the rack, the spur gears being relatively rotatable in either sense and means for drivingly connecting each gear to a respective driving motor.

2. A winch as claimed in claim 1, further comprising two hydraulic driving motors which are hydraulically connected to a common hydraulic pump and wherein the connecting means includes reduction gearing between each spur gear and its respective motor.

3. A winch as claimed in claim 1 or claim 2, further including a collar disposed between and co-axial with the two spur gears for rolling on the toothed rack.

4. A winch as claimed in any one of the preceding claims, comprising a shaft driving connected to one of the motors, one of the spur gears being mounted on the shaft for rotation therewith, and a collar rotatably mounted on the shaft and drivingly connected to the other motor, the other spur gear being rotatably mounted on the collar.

5. A winch as claimed in claim 4, wherein the one spur gear is the goaf-side gear.

6. A winch for an underground mineralwinning machine having a toothed rack with equally spaced projections on either side thereof, the rack extending lengthwise of the path of travel of the machine, including a driving wheel for meshing with the rack constituted by a pair of spur gears disposed co-axially of one another to engage the projections on the rack, and a drive shaft, the spur gears being resiliently mounted in their plane of rotation on the drive shaft.

7. A winch as claimed in claim 6, wherein each spur is mounted on the drive shaft by a hub, the hubs and the gears having interengaging radial projections and further comprising resilient elements acting between the radial projections on the gears and the radial projections on the hubs.

8. A winch as claimed in claim 7, wherein the spur gears are mounted on a common hub.

9. A winch as claimed in claim 7 or claim 8, wherein the resilient elements are compression springs centered in bores in the hub projections.

10. A winch for an underground mineralwinning machine having a toothed rack with equally spaced projections on either side thereof, the rack extending lengthwise of the path of travel of the machine, the winch being substantially as hereinbefore described with reference to the accompanying drawings.