US3855871A

US3855871A - Chain tensioning devices and drive assemblies for mining

Info

Publication number: US3855871A
Application number: US00440299A
Authority: US
Inventors: J Gibson; J Nelson
Original assignee: Underground Mining Machinery Ltd
Current assignee: Underground Mining Machinery Ltd
Priority date: 1972-06-26
Filing date: 1974-02-07
Publication date: 1974-12-24
Anticipated expiration: 1991-12-24

Abstract

A drive assembly for use with mining apparatus such as conveyors or coal ploughs includes a chain tensioning device which is in the form of a self-contained unit or cartridge.

Description

' [111 3,855,871 Dec. 24, 1974 United States Patent Gibson et al.

[ 4] CHAIN TENSIONING DEVICES AND DRIVE [58] Field of Search 74/242] FP, 242.1 R, 392

ASSEMBLIES FOR MINING [75] Inventors: John Gibson, Newton Aycliffe;

References Cited UNITED STATES PATENTS James Nelson, Shiney Row, both of England Freese 74/242! FP Primary ExaminerLeonard H. Gerin [73] Assignee: Underground Mining Machinery Limited, Durham, England Feb. 7, 1974 Attorney, Agent, or FirmThompson, Birch,-Gauth ier & Samuels 22 Filed:

ABSTRACT A drive assembly for. use with mining apparatus such as conveyors or coal ploughs includes a chain tension- 7 5 a t a D n 0 a .m n D. A 9. ,5 0U 4 4d 0].. u m. D. A 2

[62] Division of Ser. No. 266,309, June 26, 1972,

ing device which is in the form of a self-contained unit or cartridge.

abandoned.

74/2421 FP Int. 7 C 5 a g gur s PATENTEU DEC 2 41974 SHEEI10F 00 no 8 10 f u 0? PATENTEU 2 4 4 swan 30F 5 PATENTEU DQ124197! saw u nr 5 A drive assembly or station for mining apparatus such as a conveyor or a coal plough is required to drive one or more chains by way of a rotary drum. It is often desired for the drive assembly to drive the drum at a low speed very much below the normal operating speed so as to slacken or tension the previously locked chain or chains during installation or repair work, for example. To this end, a drive assembly is known which employs an additional drive motor especially for driving the drum at this low speed.

A standard fon'ri of drive assembly has main gearing in a housing which is connected to the machine frame of a conveyor, and is driven from an electric motor through a fluid'coupling. In the case of the drive assembly for a plough, -a safety device in the form ofa shear pin drum is often provided on the side of the gearbox remote from the conveyor and has shear pins which shear if the chain load becomes excessive.

When auxiliary gearing is required to drive the chain drum at a low speed, the construction described above must be extensively modified and two different types of drive assembly manufactured, one with and one without auxiliary gearing. In consequence both the manufacturer and the user have to incur the expense of holding extra stocks. Also, where the user needs to change from an assembly without auxiliary gearing to one with such gearing, or vice-'versa, difficulties are encountered since these tasks have to be perfonned in dirty and badly lit conditions in restricted spaces underground.

SUMMARY OF THE INVENTION Broadly stated, the present-invention provides a drive assembly which comprises a rotatable member which is driven from a main drive means through a transmission which includes main gearing and a toothed disc carried on a shaft; and auxiliary gearing providing a reduction ratio and including'a pinion which is movable under the action of a' shifting device to selectively engage the toothed disc to thereby drive the rotatable member via the auxiliary gearing. The transmission also includes a fluid coupling device or a flexible rubber type coupling which is disposed in a housing into which extends the shaft which carries the toothed disc. The auxiliary gearing is removable from the assembly and, in a preferred embodiment, the auxiliary gearing, the toothed disc and its shaft constitute a self contained detachable unit. The rotatable member may be a drum used to drive the chain or chains of a mining apparatus and the auxiliary gearing can be used to drive the rotatable member at a low tensioning or slackening speed in chain adjustment operations.

Auxiliary drive means which may be a fluid driven motor is preferably provided, the auxiliary drive means being operable as an alternative to the main drive means to drive the rotatable member via the auxiliary gearing. The auxiliary drive means, auxiliary gearing and the toothed disc thus constitute a chain-tensioning device which is independent of the remaining parts of the drive station. A drive assembly made in accordance with the invention is readily adaptable so that the chain tensioning device can be removed if not required. The

drive assembly can thus be more economical both from the point of view of the manufacturer and the user.

If a drive assembly without a chain tensioning device has to be converted to one with such'a device, or vice 'versa, iii an underground site, the time necessary to carry out these operations is considerably shortened by employing the drive assembly of this invention, and these operations can be carried out by untrained personnel without the adoption of special precautionary measures.

According to an optional feature of the invention the main gearing of the drive assembly may consists of primary and secondary gearing, the primary gearing being connected to a shear pin drum which is disposed substantially coaxially of and facing said further housing. The drive assembly made in accordance with the invention enables standardized primary and secondary gearirigs to be employed. This construction also ensures that the chain tensioning device will not impede the access to the drive assembly and associated equipment especially when shear pins are to be'changed. Also a minercan operate both the'chain tensioning device and ashear pin drum when the latter is provided from one 7 working position and with complete safety.

The chain tensioning device may be in the form of a self-contained unit or cartridge adapted to be intergards dimensions and splining, the chain tensioning device may be incorporated easily into the drive systems of existing installations. The fluid circuitof the auxiliary motor may include valve means which. locks the motor when the supply of fluid thereto is terminated so as to maintain the chain in tension.

DESCRIPTION or DRAWINGS 2 FIG. 1 is a diagrammatic view of a mineral mining installation showing part of a face conveyor and drive assemblies forthe conveyor and for a plough, each assembly incorporating .a chain .tensioning device in accordance with the invention,

FIG. 2 is a cross-section through a chain tensioning device showing the general arrangement of the gearing and control mechanism, I

FIG. 3 is a section taken on the line A-B-C of FIG. 2 and showing one type of main shaft construction,

FIG. 4 is a section taken on the line A-B of FIG. 2 but showing a second type of main shaft construction,

FIG. 5 is a schematic diagram illustrating the hydraulic circuit of the device.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to the drawings, FIG. 1 shows in a diagrammatic form those components of a mineral mining installation relevant to the present invention namely:

a face conveyor A, a plough B, and drive assemblies C and D for the conveyor and plough respectively.

The drive assembly for the conveyor comprises a drum CE which is driven from an electric motor CF through a gearbox CG, a chain tesnioning device CH and a fluid coupling-CI. The drive assembly for the plough likewise comprises a drum DE, electric motor 3 DF, gearbox DG equipped with a shear pin drum DK,

I chain tensioning device DH and fluid coupling DJ.

Each gearbox houses main and secondary gearing in known manner, the main gearing of gearbox DG driving the shear pin drum. Each of the components CF to C] and DF to DJ has flanges whereby the components are bolted together.

When the installation is working, the drum CE is continuously driven so as to circulate a pair of endless chains L which carry the flights of the conveyor, while the drum DE is driven alternately in opposite directions so that an endless chain M draws the plough B back and forth along the face.

When, for example, during repair work it is necessary to tension either the pair of chains L or the chain M, the electric motor in the appropriate drive assembly is halted, the chain M or pair of chains L, as the case may be, locked by a locking device N or respectively, and the appropriate chain tensioning device operated. FIG.

' 1 shows the situation after both tensioning devices have operated to tension the lower, return runs of the chains so as to produce amounts of slack chain between the drum andthe locking devices. With the tensioning devices maintaining the lower runs in tension, this slack chain may be removed.

Referring now to FIGS. 2 and 3, the tensioning device comprises a housing generally indicated at l. A main shaft assembly 2 is supported in a bearing 19 supported in the front wall of the housing and consists of a stub shaft component 5 and a socket component 6, the former of which projects forwardly of the housing. The

shaft components

5, 6 have

peripheral flanges

51 and 61 respectively. Bolts 52 secure the flanges together with a gearwheel 3 sandwiched between them. The socket component is internally splined and the stub shaft component externally splined so that the former can receive the splined input shaft of the gearbox and the latter can be inserted into the fluid coupling in the place of the gearbox input shaft. Within the housing at its other end, a driving pinion 7 is secured to the output'shaft 71 of a hydraulic motor 72 bolted to the housing. An intermediate gearwheel 8 which is rotatable on a shaft 81 in mesh with the pinion 7 is slidable along this shaft into and out of mesh with the gearhweel 3, under the action of a selector fork which engages with the gearwheel 8 and is made to slide along a rod 151 by an operating mechanism supported by a box 12 bolted to the housing. The operating mechanism comprises a handle, 121, spindle 122 and an eccentric pin 123 cooperating with a groove in the body part of the selector fork.

The spindle 122 has a cam surface 124 which causes is operable, on opening of the microswitch, to interrupt the power supply to the electric motor. To enable the tensioning device when assembled to be operated by either hand as is more convenient, the box 12 and the fork operating mechanism can be bolted to either side of the housing, which is provided with two suitable openings and two

rods

151, 152, on either of which the selector fork can be supported.

The construction shown in FIGS. 2 and 3 makes use nents. This rigidity of connection renders it difficult to 4 accommodate errors of alignment when assembling the chain tensioning device with the fluid coupling and gearbox and, to overcome this problem, the stub shaft and socket components may be interconnected with a certain degree of play. Referring now to FIG. 4, it will be seen that the main gearwheel 3, in the form of an externally toothed ring, is bolted to the rim of the peripheral flange 51 of the stub shaft component 5. The ring is formed at intervals with bores 31 into which project pins 62 bolted to the flange 61 of the socket component 6. The shanks of the pins arecovered with flexible of the pins, whereby the two

flanges

51, 61 are coupled by a flexible coupling of the pin type. In this modification, the stub shaft component is necessarily supported by two sets of bearings 19 instead of the single set in the main embodiment.

A hydraulic control circuit is housed in a manifold (FIGS. 1 and 5) the circuitincluding a control valve 101 enabling the motor 72 to be placed in neutral or to be driven forwards or' in reverse and check valves 102 to isolate and lock the motor 72 whenthe valve 101 is placed in neutral. A pressure gauge 103 allows the pressure in the system (and hence the chain tension) to be observed, and an adjustable relief valve 104 is provided to divert the flow of fluid from the motor when once a desired tension has been achieved.

It will be understood by those skilled in the art that modifications may be made to the apparatus described above within the spirit and scope of the invention. Thus, for example, in the embodiment shown in FIG. 3, it is not necessary for the gearwheel 3 to be sandwiched between the

flanges

51, 61. Instead, these flanges can be bolted directly to each other and the gearwheel 3 f xed to the side of the flange 61.

In some applications it may be desirable for the drive assembly to extend parallel to the conveyor and in this, or in others, alternative hydraulic circuits may be found to be preferable. The sequence of operations for the apparatus describedwith reference to the drawings gear. To prevent, the electric motor CF or, DF being switched on when the hydraulic drive is engaged, initial movement of the selector handle actuates microswitch 44 which activates the electrical interlock to interrupt the power supply. I

2. The chain locking device N or O is engaged.

3. The directional flow control valve 101 is operated. The hydraulic motor 72 then drives the chain drum CE or DE via the main gearbox CG or DG. 4

4. When the required chain tension is reached, this being determined by reference to the pressure gauge 103 or by operationfof the relief valve 104, the flow control valve 101 is moved to neutral and pressure then held in the system by means of check valves 102. The chain M or pair of chains L can be uncoupled and slack chain removed.

6. The directional flow control valve 101 is operated to reverse the hydraulic motor 72, until the chain locking device N or O is free.

7. The flow control valve 101 is returned to neutral and the chain locking device N or O removed.

8. The selector handle 121 is operated to disengage gear and automatically disengage the electrical interlock on the power supply.

We claim:

l. A mineral mining installation including a conveyor, at least one chain extending therealong, and a ii. means for driving said chain drum at a reduced speed for'chain tensioning and slackening operations, said driving means comprising;

A. an auxiliary motor having a drive shaft carrying a second toothed gear;

B. an intermediate toothed gear shiftable between a first position in which it transmits rotary motion between said first and second toothed gears and a second position in which said first and second toothed gears are out of drivable engagement;

C. shifting means operable to move said intermediate gear between the two said positions to selectively transmit rotary motion from said auxiliary motor through said transmission systemto said chain drum; and

D. a housing supporting at least said auxiliary motor, said second toothed gear and said intermediate toothed gear, said housing being readily detachable from the remainder of said drive assembly.

2. The mineral mining installation of claim 1, wherein said transmission system further includes a resilient coupling unit and a housing within which said resilient coupling unit is contained, said transmission shaft extending into said resilient coupling unit housing and being drivably engaged to said resilient coupling unit.

3. The mineral mining installation of claim 2, wherein said housing is detachably secured to said resilient coupling unit housing.

4. The mineral mining installation of claim 2, including a main gear box having primary and secondary gearing and having a gear box housing therefor, a shear pin drum being disposed so as to face said gear box housing, said shear pin drum being connected to said primary gearing.

5. The mining installation of claim 1 wherein said main drive motor is an electric motor and said auxiliary motor is a fluid powered motor.

6. A mineral mining installation including a conveyor, at least one chain extending therealong, and a drive assembly mounted to said conveyor and comprising;

a. a chain drum around which said chain passes, said chain drum being rotatable to circulate said chain;

b. a main drive motor; and

c. a transmission system for transmitting rotary motion from said motor to said drum, said transmission system comprising a main gear box driven fromsaid motor, a chain tensioning device driven from said main gear box, and a resilient coupling unit driven from said chain tensioning device and driving said chain drum, each of said main gear box, chain tensioning device and resilient coupling unit having a respective housing, the housing of said chain tensioning device being releasably secured to the housings of said main gear box and resilient coupling unit, said chain tensioning device further having a main shaft supported for rotation within said housing, said main shaft being releasably and drivably coupled with said main gear box and said resilient coupling unit; an auxiliary motor mounted on the said housing of said chain tensioning device and having a drive shaft projecting into said housing; a train of gears for driving said main shaft from said drive shaft, and means for engaging and disengaging said train of gears.

7. The mineral mining installation of claim 6, wherein said main drive motor is an electric motor and wherein circuit means is provided for feeding current to said motor, and wherein switch means is provided for interrupting said circuit means when said train of gears is engaged.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENTNO. 5, 71 DATED 1 December 24, 1974 INVEN OM John Gibson and James Nelson nucmmmdmmmmrwmmsmmemweqmmfimdmmmamtmtwmLdmmPmmt are hereby corrected as shown below:

Col. 1, line 3, cancel "This application is a division of Ser. No. 266,309, filed June 26, 1972, now abandoned." and insert This application is a division of Ser. No. 266,309, filed June 26, l972.--

Claim 6 col. 6, line 20 cancel "main gear box" and insert resilient coupling unit Claim 6 col. 6, lines 21-22 cancel "main gear box, and a resilient coupling unit" and insert resilient coupling unit, and a main gear box Col. 1, line 13, after "work" cancel the comma Col. 2, line 12, "consists" should be consist Col. 2, line 65, "tesnioning" should be tensioning Col. 3, line 44, "gearhweel" should be gearwheel Signed and Scaled this twenty-eight D ay Of October 1 9 75 [S AL] a A ties t:

RUTH C. MASON Arresting Officer

Claims

1. A mineral mining installation including a conveyor, at least one chain extending therealong, and a drive assembly for circulating said chain, said drive assembly being mounted to said conveyor and comprising; a. a chain drum around which said chain passes; b. a main drive motor; and c. a transmission system drivably interconnecting said drive motor and said chain drum, said motor driving said chain drum through said transmission system at a predetermined normal operating speed, said transmission system comprising at least; i. a transmission shaft carrying a first toothed gear; ii. means for driving said chain drum at a reduced speed for chain tensioning and slackening operations, said driving means comprising; A. an auxiliary motor having a drive shaft carrying a second toothed gear; B. an intermediate toothed gear shiftable between a first position in which it transmits rotary motion between said first and second toothed gears and a second position in which said first and second toothed gears are out of drivable engagement; C. shifting means operable to move said intermediate gear between the two said positions to selectively transmit rotary motion from said auxiliary motor through said transmission system to said chain drum; and D. a housing supporting at least said auxiliary motor, said second toothed gear and said intermediate toothed gear, said housing being readily detachable from the remainder of said drive assembly.

6. A mineral mining installation including a conveyor, at least one chain extending therealong, and a drive assembly mounted to said conveyor and comprising; a. a chain drum around which said chain passes, said chain drum being rotatable to circulate said chain; b. a main drive motor; and c. a transmission system for transmitting rotary motion from said motor to said drum, said transmission system comprising a main gear box driven from said motor, a chain tensioning device driven from said main gear box, and a resilient coupling unit driven from said chain tensioning device and driving said chain drum, each of said main gear box, chain tensioning device and resilient coupling unit having a respective housing, the housing of said chain tensioning device being releasably secured to the housings of said main gear box and resilient coupling unit, said chain tensioning device further having a main shaft supported for rotation within said housing, said main shaft being releasably and drivably coupled with said main gear box and said resilient coupling unit; an auxiliary motor mounted on the said housing of said chain tensioning device and having a drive shaft projecting into said housing; a train of gears for driving said main shaft from said drive shaft, and means for engaging and disengaging said train of gears.