Drive Arrangements for Mining Machines

The present invention relates to mineral mining installations and more particularly to drive arrangements for mineral winning machines. It is well known in the mining art to employ a chain driven machine, such as a plough, which is moved back and forth along a mineral face. Normally the machine is guided by a guide on or at one side of a scraper chain conveyor composed of a series of channel sections or pans arranged end-to-end. Chainless drive systems for winning machines are also known. In one system of this type a toothed track or rack extends along the path of movement of the machine and a driven toothed wheel engages with the rack. To enable the installation to be shifted up in stages and to enable the installation to cope with unevenness in the floor it is usual to provide some limited mobility between the individual channel sections or pans of the conveyor. This requirement for mobility however causes serious problems with the known forms of chainless drives where a correct meshing between the track and the toothed wheel is needed. There is also a need, in general, for a drive system which is readily adaptable to chain and chainless drives without extensive work.

With regard to the foregoing a general object of the present invention is to provide an improved drive arrangement for a mineral winning machine.

In a drive arrangement for a mineral winning machine which employs a rack extending along the path of movement of the machine, the invention comprises plural pinions meshing with the rack and means for driving both pinions in the same direction.

According to the present invention there is also provided a drive arrangement for a mineral winning machine guided for movement back and forth along a mineral face. The arrangement is composed of a transmission housing supported by the machine. The housing contains first and second parallel shafts, bearings rotatably supporting said shafts and gear means mounted at one end of the shafts. Each of said gear means meshes with a common rack extending along the path of movement of the machine whereby the shafts can be driven in the same direction by drive means supported by the machine. The transmission housing is preferably detachably mounted to the top and to the goaf side of the body of the machine so that the entire transmission composed of the housing and the shafts with their bearings and gear means can be removed as a unit from the body. The term body of the machine is used here in a general sense and the body may in fact be a housing of the main drive means. The main drive means may employ a driven gear which drives the shafts. This driven gear can then be a replaceable item and by fitting a conventional chain wheel to the associated driven vertical shaft instead of the gear wheel and by removing the transmission unit the drive arrangement can be readily converted to a chain drive. The drive means and the vertical driven shaft may otherwise be of conventional design.

The common rack for receiving the gear means or pinions, usually at the lower end of the shafts, is preferably flexible and constructed from elongate sections interconnected in articulated manner. This provides the desired mobility and the design can be such that one of the pinions of the drive arrangement is properly meshed with the rack to propel the machine even if the other pinion is not properly meshed. Nevertheless, it is desirable to maintain the pinions relatively close together to ensure the drive and loading forces are properly distributed. With a view to further improving the flexibility of the drive and to avoid unduly high pressure on the flanks or teeth of the pinions, the shafts are preferably flexibly supported to allow relative flexure in the direction of movement of the machine and/or diagonally thereto. To achieve this, the bearings for the shafts may be mounted in elastic rings or the like. Gearwheels can be mounted at the upper ends of the shafts to mesh with the driven gear of the drive means. One or both these gear wheels meshing with the driven gear of the main drive means may also be flexibly mounted to again avoid unduly high pressures.

Although it is convenient for the shafts to be driven via a common driven gear it is also possible to utilize separate drives as for example hydromotors.

In a drive system for propelling a mineral winning machine along a toothed track or rack by a toothed wheel or the like engaging therewith, the invention includes a generally L-shaped auxiliary transmission housing detachably mounted to the machine and having a top section and a side section. First and second generally upstanding shafts are located in said side section of the housing and carry pinions at their lower ends and gear wheels at their upper ends. Both pinions mesh with the toothed track. Bearings are used to rotatably mount the shafts. A detachable gear wheel is mounted on a driven shaft of separate drive means and meshes with the gear wheels at the upper ends of the shafts within the top section of the housing. Thus, the auxiliary transmission housing, the shafts and their bearings can all be removed as a unit and the gearwheel on the driven shaft replaced by a chain wheel for effecting a conventional chain drive for the machine.

The invention may be understood more readily and various other features of the invention may become apparent from consideration of the following description.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings wherein:

FIG. 1 is a part-sectional end view of a mineral mining installation employing a drive arrangement in accordance with the invention; and

FIG. 2 is a part-sectional plan view of the arrangement and installation depicted in FIG. 1;

As shown in the drawings, a mineral mining installation, used particularly in longwall coal working, employs a scraper-chain conveyor 10 which is of known design. The conveyor 10 is constructed from individual channel sections or pans arranged end-to-end and along which is circulated a scraper-chain assembly partly depicted in FIG. 2. Each channel section or pan has generally sigma-shaped side walls adjoined by a floor and the channel sections of the conveyor 10 are interconnected to permit a certain degree of free mobility between the ends of the channel sections as is known per se.

A coal cutting machine 11 is supported on the conveyor channel sections which rest on the floor 34 of the working. As is also known the machine employs a shearer drum 16 mounted to the machine body with means 17 permitting the drum 16 to be raised or lowered. The body of the machine 11 carries drive means and the machine 11 is moved back and forth along the conveyor 10 to strip coal from the face with the aid of the shearer drum 16. The coal which is won in this manner is transported away by the conveyor 10. The conveyor 10 is shifted up from time-to-time by shifting means in accordance with the winning progress.

The body of the machine 11 has skids 14 which engage on the upper flanges of the side walls of the channel sections. At the goaf side remote from the coal face there is a guide 12 made up from rails affixed with attachments to the goaf side walls of the conveyor channel sections. The machine body has one or more guide blocks 13 which mate with the guide 12.

The drive arrangement of the invention will now be described. The drive means carried by the body of the machine may be of conventional design and has an upstanding driven output shaft 18. The drive arrangement comprises an auxiliary miter-gear transmission mounted in a detachable housing 30 which is mounted to the body of the machine 11 so as to be replaceable as a unit. The housing 30 is generally L-shaped with an upper section and a depending section engaging on the top and the goaf side of the body of the machine 11. As shown the arrangement has two upstanding stubshafts 22, 23 rotatably mounted in bearings 31, 32 in the depending part of the housing 30. The lower ends of the shafts 22, 23 carry pinions 24, 25 respectively which mesh with a common rack 26 extending along the conveyor 10. The upper ends of the shafts 22, 23 carry gears 20, 21 respectively which mesh with a gear wheel 19 detachably supported on the drive shaft 18. As shown, drive shaft 18 is substantially parallel to shafts 22, 23 which are located in a plane that is laterally spaced from shaft 18. The gears 20, 21 and gearwheel 19 are located in the upper section of the housing 30. The bearings 31, 32 are preferably supported in flexible rings or the like as indicated by the dotted lines 33 in FIG. 1 to permit the shafts 22, 23 to flex in a plane parallel to the floor 34. In this way, the pinions 24, 25 can mesh with the rack 26 in a manner whereby unduly high forces between the flanks of the teeth of the pinions 24, 25 and the rack 26 can be avoided. The flexible mounting for the shafts 22, 23 can be adapted so that the shafts 22, 23 can only move relative to one another in a direction parallel to th rack 26. The rack 26 is assembled from individual elongate sections each of which may have a length approximately the same as that of the channel sections of the conveyor 10 so that each channel section has one rack section allocated to it. The rack sections have interengaging projections and recesses at their ends which form balland-socket type joints 27 (FIG. 2) permitting a certain degree of limited freedom of movement between the rack sections. The rack sections are detachably secured to brackets 28 arranged at the goaf sides of the conveyor channel sections with the aid of screws 29.

As can be readily appreciated, rotation of the drive shaft 18 will be transmitted to the pinions 24, 25 which will propel the entire machine along the rack 26. The entire auxiliary transmission can be removed however by disconnecting the housing 30 and the shafts 22, 23 etc., and the gearwheel 19 can be removed from the shaft 18 and replaced by a conventional chain wheel for a chain drive.