GB2113305A

GB2113305A - Monitoring apparatus

Info

Publication number: GB2113305A
Application number: GB08300211A
Authority: GB
Inventors: Dr Thomas Trumper; Gerhard Merten; Horst Linke; Franz Roling
Original assignee: Gewerkschaft Eisenhutte Westfalia GmbH
Current assignee: Gewerkschaft Eisenhutte Westfalia GmbH
Priority date: 1982-01-07
Filing date: 1983-01-06
Publication date: 1983-08-03
Also published as: FR2519373B1; FR2519373A1; GB8300211D0; GB2113305B; BE895547A; DE3200176A1

Abstract

Apparatus is provided for monitoring the working stroke of each hydraulic ram 14 of a group of hydraulic rams. Each ram 14 has a cylinder 15 and a piston movable relative thereto. The apparatus comprises an indicator 21 which is connected to each of the rams by a respective transmission element 23. Each of the transmission elements 23 transmits a signal to the indicator 21 which is dependent upon the relative movement of the piston of the associated ram 14 relative to its cylinder 15, so that the indicator provides an indication of the position of each of the pistons relative to its cylinder. The transmission element may be hydraulic, or mechanical (e.g. a Bowden cable). <IMAGE>

Description

SPECIFICATION Monitoring apparatus This invention relates to apparatus for monitoring the working strokes of a group of hydraulic rams, and in particular with monitoring apparatus for the hydraulic rams used for adjusting the cutting horizon of a mineral winning machine such as a plough.

In order to adjust the cutting horizon of a mineral winning machine such as a coal plough, control means of various types are known. With these known types of control means, the position of the plough guide, that is to say the longwall conveyor carrying the plough guide, can be tilted by means of hydraulic control rams in such a manner that the plough dips towards, or rises away from, the floor of the longwall working. In a known installation of this type, the control rams are arranged between the plough guide (or a goaf-side conveyor attachment which carries the plough guide) and the head pieces which attach the conveyor to the advance mechanism of hydraulic roof support units positioned on the goaf side of the conveyor.In use, the control rams tilt the plough guide in the plane at right-angles to the floor of the working, there being a direct relationship between the working strokes of the rams and angle of tilt. Where the conveyor is a scraper-chain conveyor, control rams are usually associated only with alternate channel sections (pans) of the conveyor. During the tilting movement, the plough guide pivots with the conveyor about the pivot joints of the head pieces. The advance mechanisms have guide rod systems which guide the roof support units during advance. The guide rod systems also provide goaf-side bracing of the plough guide against the tilting forces occuring during operation of the plough. The cylinders of the hydraulic control rams are connected to the head pieces by means of ball-and-socket joints.

It has also been proposed to fit the control rams in the reverse position between the guide rod systems and the conveyor, that is to say with their cylinders connected to the conveyor by means of ball-and-socket joints. This permits the control rams to be arranged in a relatively steeply inclined manner, so that a space-saving overall arrangement of the rams is achieved.

Difficulties are encountered with these known arrangements in controlling the extension of the individual control rams. This is particularly the case when the rams are arranged in groups of, for example, three rams, each group being associated with a respective control valve arranged on the goaf side of the conveyor. From the position at which the control valves are operated, it is not possible to monitor, in a reliable manner, the working stroke of the individually connected control systems. In practice, this can lead to inaccurate tilting of the conveyor, and hence poor control of the cutting horizon of the plough. In particular, the entire installation may be tilted in the same direction, when differential tilting is required for different portions thereof.

The aim of the invention is to provide a simple and operationally-reliable monitoring apparatus whereby the working strokes of the individual control rams can be efficiently monitored, so that the rams can be controlled to have different working strokes.

The present invention provides apparatus for monitoring the working stroke of each hydraulic ram of a group of hydraulic rams, each ram having a cylinder and a piston movable relative thereto, the apparatus comprising an indicator which is connected to each of the rams by a respective transmission element, the apparatus being such that the indicator provides an indication of the position of each of the pistons relative to its cylinder.

Preferably, the indicator is provided with separate indicating means for each of the rams, a respective transmission element leading from each of the indicating means to its associated ram.

Thus, a common indicator is associated with several, for example three, adjacent hydraulic rams. The indicator indicates the positions of the pistons of the rams relative to their cylinders, preferably in the form of an analogue display, so that reliable monitoring and control of the working strokes of the individual rams is possible.

The indicator can be of small dimensions, and is expediently connected to a control valve which is provided for.controlling the flow of pressurised hydraulic fluid to each of the rams.

Advantageously, the indicator is connected to the control valve to form a single constructional component.

In a preferred embodiment, the transmission elements are disposed within hydraulic hoses which are used to supply the rams with pressurised hydraulic fluid. Preferably, each of the rams is provided with an inlet port, the inlet ports being connected to the hydraulic hoses containing the transmission elements.

The transmission elements may be hydraulic, electrical or mechanical elements.

Each of the transmission elements may be a mechanical transmission element such as a Bowden cable. Advantageously, the inner strand of each Bowden cable is connected to that part of the associated ram which moves during the working stroke of the ram, and to the respective indicating means. Preferably, each of the indicating means is constututed by a scale and a spring-loaded pointer which is movable over the scale. Conveniently, each of the pointers is slidably mounted in a respective guide formed within the indicator, and the pointers, and scales are disposed behind respective viewing windows provided in the indicator.

The inner strand of each Bowden cable may be connected to the piston or the piston rod of the associated ram. In the latter case, the inner strand of each Bowden cable may be attached to a bracket fixed to the associated piston rod, said inner strand passing through a tubular guide attached to the cylinder of the associated ram and through a tubular member fixed to said bracket and slidably mounted in the tubular guide.

Advantageously, each of the hoses accommodating the transmission element is connected to the control valve by means of a Tjoint.

In a preferred embodiment, each of the Bowden cables is provided with an adjustment device for adjusting the length of that Bowden cable. Advantageously, each of the Bowden cables is constituted by a plurality of sections, the adjustment device of each Bowden cable being disposed between a pair of adjacent sections of that Bowden cable. In this case, each adjustment device may be constituted by a coupling member having internally-threaded sockets at each end thereof, said internally-threaded sockets being of opposite hands, and being threadably connected to respective threaded pins arranged at the adjacent ends of the two sections of the Bowden cable connected by that adjustment device, the coupling member of each adjustment device being disposed within a sleeve-like rotary member, and being connected thereto for rotation therewith.Preferably, the rotary member of each adjustment device has a non-circular bore which contains the respective coupling member, said coupling member also having a non-circular cross section. Conveniently, said bore of each rotary member has a generally elliptical cross-section.

Each of said threaded pins may be arranged on a respective slide member, said slide members being secured to the inner strands of the respective Bowden cable sections in such a manner that their axes are off-set from the central longitudinal axes of said inner strands.

Advantageously, each of the slide members is disposed in a respective eccentric bore formed in a connection member attaching the adjustment device to the adjacent Bowden cable section.

The invention also provides apparatus for controlling the position of a mineral mining machine movable along guide means, the apparatus comprising a plurality of hydraulic control rams which are pivotally arranged between the guide means and a support structure for tilting the guide means, each hydraulic control ram having a cylinder and a piston movable relative thereto, the hydraulic control rams being arranged in a plurality of groups, wherein each group of hydraulic control rams is associated with a respective indicator, each of the indicators being connected to each of the rams of its group by a respective transmission element, the apparatus being such that each indicator provides an indication of the position of each of the pistons of the rams of the associated group relative to its cylinder.

Preferably, the guide means is constituted by a guide mounted on a scraper-chain conveyor.

Two forms of monitoring apparatus constructed in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a side elevation of a single hydraulic contral ram fitted on the goaf side of a longwall conveyor; Fig. 2 is a schematic representation of the first form of monitoring apparatus together with two hydraulic control rams of an associated group of rams; Fig. 3 is a vertical cross-section through the indicator forming part of the monitoring apparaus of Fig. 2; Fig. 4 is a cross-section taken on the line IV IV of Fig. 5; Fig. 5 is a cross-section taken on the line V-V of Fig. 3; Fig. 6 is a part-sectional elevation of the second form of monitoring apparatus; Fig. 7 is a cross-section taken on the line VII VII of Fig. 6;; Fig. 8 is a cross-section taken on the line VIII-- VIII of Fig. 6; and Fig. 9 is a cross-section taken on the line IX- IX of Fig. 6.

Referring to the drawings, Fig. 1 shows part of equipment for controlling the cutting horizon of a mineral winning machine such as a coal plough.

The plough (not shown) is movable to and fro along a scraper-chain conveyor 10 disposed alongside a mineral face. As is shown, the conveyor 10 is constituted by a plurality of channel sections (pans) arranged end-to-end. A guide (not shown) is arranged on the face side of the conveyor 10, and the plough is mounted for reciprocal movement along this guide. A plurality of roof support units (not shown) are provided at the goaf side of the conveyor 10. Each roof support unit is connected to the conveyor 10 by a respective advance mechanism, which includes a guide rod system 11. Each guide rod system 11 is generally constituted by two resilient, circular guide rods, whose front (face-side) ends are connected to a respective head piece 12. Each head piece 12 is connected to the conveyor 10 by a respective pivotjoint 13.Each pivot joint 13 has a pivot pin which extends parallel to the longitudinal direction of the conveyor 10. Each guide rod system 11 is guided in the direction R of advance on the associated roof support unit; and is also pivotable, to a limited extent, in the plane at right-angled to the floor of the working, relative to that roof support unit. Alternate roof support units are each provided with a hydraulic ram 14, these rams being pivotally mounted between the respective guide rod systems 11 and the conveyor 10. The cylinder 15 5 of each ram 14 carries a ball 1 6 which is mounted in a respective socket 1 7 provided on a plate 18 attached to the goaf side of the conveyor 10. The piston rod 19 of each ram 14 is likewise provided with a ball 20 which is mounted in a respective socket 20' associated with the head piece 12 of the accociated guide rod system 11.

The hydraulic rams 14 are used to tilt the conveyor 10, and so control the cutting horizon of the plough. Thus, by extending or retracting the rams 14, the conveyor 10, together with its guide, can be tilted in the plane at right-angles to the floor of the working, so that the plough will be tilted towards or away from the floor. Usually, the rams 14 are arranged in groups of at least three adjacent rams, each group being controlled by a respective control valve (not shown). The control valves may be arranged on the conveyor 10 or on the plate 18.

Fig. 2 shows two rams 14 of a group of three rams. This group is provided with a common indicator 21. This indicator 21 is attached to the control valve of the group; and, for this purpose, the indicator has a flange 22 for detachable connection to that control valve. The other rams 14 of the installation are also arranged in groups of three, each group likewise being associated with a common indicator 21. Each ram 14 of each group is connected to the associated indicator 21 by a respective transmission element 23, and each indicator has separate indication means for each of the associated rams. The transmission elements 23 are protected within hydraulic hoses 24, which connect the indicators 21 to their rams 14.For this purpose, the cylinder 1 5 of each ram 14 is provided with a hydraulic inlet port 25, to which the associated ram 14 is connected by means of a standard hose coupling. The hoses 24 of each group are bunched together and connected to a port 26 associated with the respective indicator 21 (see Figs. 4 and 5).

Each indicator 21 has a separate pointer 27 for each of the associated rams 14, each pointer 27 being movable along a respective cylindrical guide 28 formed within that indicator and moving across a respective scale 29. The scales 29 and the pointers 27 can be viewed, from the exterior, through respective windows 30 made of transparent piastics material or glass. Each of the pointers 27 is biased, by a respective helical spring 31 (see Fig. 3), towards a zero position which corresponds to the fully-retracted position of the piston of the associated ram 14. The springs 31 are positioned within the corresponding guides 28.

In the embodiment of Figs. 1 to 5, each of the transmission elements 23 is a Bowden cable. The Bowden cables 23 each have an inner strand 32 slidably guided within an outer sleeve. One end of each inner strand 32 is connected to the associated pointer 27, the other end of that inner strand being connected to the piston rod 1 9 of the associated ram 14. The cylinder 1 5 of each ram 14 is provided with a small, external tubular guide 33 (see Fig. 2). A tubular member 34 is slidably mounted within each of the guides 33, the free ends of the tubular members being secured to crossbars 35 associated with the piston rods 19 of the respective rams 14.The inner strands 32 of the Bowden cables 23 pass laterally through the ports 25 of the cylinders 1 5, through the tubular guides 33 and the tubular members 34, and are secured to the crossbars 35 at 36. The arrangement is, therefore, such that, when the piston (not shown) of one of the rams 14 is extended, the pointer 27 of the associated indicator 21 is moved over its scale 29, against the force of the associated spring 31, by the inner strand 32 of the associated Bowden cable 23.

Thus, the pointers 27 indicate, on their scales 29 and in the form of an analogue display, the extent to which each piston is extended from the cylinder 1 5 of its ram 14. In this way, it is possible to move the pistons of the individual rams 14 of each group in and out differentially with the aid of the common control valve, and to monitor the outward movement of the pistons of the rams 14.

It is also possible to connect the inner strands 32 of the Bowden cables 23 directly to the pistons of the rams 14. In this case, the inner strands 32 of the Bowden cables 23 would be passed into the spaces within rams 14 through bores in their cylinders 1 5. Each of these bores would be provided with a guide bush for the associated Bowden cable 23, the guide bushes being effective to seal off each cylinder 1 5 at the piston rod side. The inner strands 32 of the Bowden cables would be secured to the pistons adjacent to the guide bushes. In this arrangement, the parts 33, 34 and 35 would be dispensed with.

Figs. 6 to 9 show a preferred form of monitoring apparatus. As this form of apparatus is basically similar to that of Figs. 2 to 5, like reference numerals will be used for like parts, and only the modified parts will be described in detail.

As with this embodiment of Figs. 2 to 5, each indicator 21 has three ports 26 for the hydraulic hoses 24 which lead to the rams 14 associated with that indicator. The hoses 24 also accommodate Bowden cables (or other mechanical transmission elements), and serve to supply (and discharge) hydraulic pressure medium to (and from) the hydraulic rams 14. Fig. 6 illustrates only one ram 14, and its connection to the indicator 21. The other rams 14 of the installation are connected to their respective indicators 21 in the same manner, so this method of connection will be described in detail only for the illustrated ram. The inner strand 32 of the Bowden cable, here consists of several sections 32A, 32B, 32C and 32D, which are firmly interconnected to resist tensile forces.One end of the section 32A of the Bowden cable inner strand is secured, at 40, to the piston 41 of the ram 14.

The section 32A passes laterally out of the ram 14, via the port 25 secured to the cylinder 15, and its other end is connected to the section 32B by a swivel coupling 42 in such a manner as to resist tensile loads. The section 32B has, at its opposite end, a cylindrical slide member 43 which is arranged eccentrically in relation to the section 32B (see Fig. 7). The section 32B lies within, and is protected by, a hydraulic, high-pressure hose 24A. The hose 24A is detachably connected to the port 25 by means of a coupling sleeve 44. The swivel coupling 42 lies within the hose 24A (or within its coupling sleeve 44).

The hose 24A is connected, by way of an adjustment device 45, to a T-joint 46. The T-joint 46 is effective to connect the hose 24A to the indicator 21, and to the associated control valve (not shown). A hydraulic high-pressure hose 24B, which leads to the control valve, is connected to the T-joint 46 by a releasable hose coupling 47. A further high-pressure hose 24C connects the Tjoint 46 to the indicator 21 by a releasable hose coupling 49.

The adjustment device 45 has a coupling member 50 which, at one end, has an axiallyextending bore 51 having a left-hand thread; and, at the other end, an axially-extending bore 52 having a right-hand thread. A threaded bolt 53, which is secured to the slide member 43, is screwed into the bore 51. A threaded bolt 54 is screwed into the bore 52, the bolt 54 being secured to a slide member 55. The slide member 55 lies within the through bore of the T-joint 46, and is connected to the Bowden cable inner strand section 32C. At its other end, this section 32C has a piston 56 which sealingly slides in a piston guide 57 provided within the indicator 21.

The Bowden cable inner strand section 32D is secured to the piston 56, this section passing round a roller 58, and being connected to the pointer 27 acted upon by the spring 31.

The coupling member 50 of the adjustment device 45 lies within an axial bore 60 of a sleevelike rotary member 59. The rotary member 59 is fitted between the T-joint 46 and the hose 24A, and is rotatably connected to these parts by hoses or tubular couplings 48 and 48'. As shown best in Fig. 8, the coupling member 50 is roughly elliptical or oval in cross-section. Moreover, in the zone of the coupling member 50, the bore 60 has a complementary elliptical or oval cross-section, so that the rotary member 59 is connected to, and is rotatable with, the coupling member 50. The slide member 43 is located in a circular bore 61 formed in the tubular coupling 48' (see Fig. 7), the bore 61 being arranged off-centre with respect to the central longitudinal axis of the tubular coupling 48'.The axial bore of the T-joint 46 that accommodates the other slide member 55 is similarly arranged off-centre in relation to the central longitudinal axis of the hose 24C.

When the control valve is actuated, hydraulic fluid flows through the hose 24B, the T-joint 46, the bore of the rotary member 59, and the hose 24A into the space within the ram 14. The indicator 21 is sealed off from the hose 24C by means of the piston 56. With the aid of the adjustment device 45, the length of the Bowden cable can be varied by turning the rotary member 59. In this way, the pointer 27 can be adjusted.

The Bowden cable inner strand sections 32A, 32B, 32C and 32D are prevented from turning because of the eccentric arrangement of the slide members 43 and 55; the slide member 43 sliding in the likewise eccentrically-arranged bore 61 of the tubular coupling 48', and the slide member 55 sliding in the likewise eccentrically-arranged bore in the T-joint 46. After the adjustment has been made, the adjustment device 45 can be secured against rotation, by means of a device (not shown), in order to immobilise the rotary member 59.

It will be apparent that the monitoring apparatus described above could be modified in a number of ways. For example, the mechanical transmission elements 23 could be replaced by hydraulic transmission means. In this case, smalldiameter hoses would be employed as the transmission elements, and these hoses could be secured to, for example, small hydraulic rams attached to the cylinders 1 5 of the rams 14. The cylinders of these small rams would be equivalent to the tubular guides 33 of the apparatus of Figs.

2 to 5, and their pistons would be equivalent to the tubular members 34. At its other end, each of the hydraulic hoses would be connected to a small cylinder within the respective indicator 21.

Pistons would slide within these cylinders, the pistons pressurised hydraulic fluid which is displaced when the pistons move in and out of the rams 14, is transmitted from the small hydraulic rams to the cylinders within the indicators, and has the effect of moving the pointers 27, that is to say the spring-loaded setting pistons connected to them.

Claims

1. Apparatus for monitoring the working stroke of each hydraulic ram of a group of hydraulic rams, each ram having a cylinder and a piston movable relative thereto, the apparatus comprising an indicator which is connected to each of the rams by a respective transmission element, the apparatus being such that the indicator provides an indication of the position of each of the pistons relative to its cylinder.

2. Apparatus as claimed in claim 1, wherein the indicator is provided with separate indicating means for each of the rams, a respective transmission element leading from each of the indicating means to its associated ram.

3. Apparatus as claimed in claim 1 or claim 2, wherein the transmission elements are disposed within hydraulic hoses which are used to supply the rams with pressurised hydraulic fluid.

4. Apparatus as claimed in claim 3, wherein each of the rams is provided with an inlet port, the inlet ports being connected to the hydraulic hoses containing the transmission elements.

5. Apparatus as claimed in claim 3 or claim 4, further comprising a control valve for controlling the flow of pressurised hydraulic fluid to each of the rams.

6. Apparatus as claimed in claim 5, wherein the indicator is connected to the control valve to form a single constructional component.

7. Apparatus as claimed in any one of claims 1 to 6, wherein each of the transmission elements is a mechanical transmission element.

8. Apparatus as claimed in claim 7, wherein each of the transmission elements is a Bowden cable.

9. Apparatus as claimed in claim 8. wherein the inner strand of each Bowden cable is connected to that part of the associated ram which moves during the working stroke of that ram, and to the respective indicating means.

1 0. Apparatus as claimed in claim 9, wherein each of the indicating means is constituted by a scale and a spring-loaded pointer which is movable over the scale.

11. Apparatus as claimed in claim 10, wherein each of the pointers is slidably mounted in a respective guide formed within the indicator.

12. Apparatus as claimed in claim 10 or claim 11, wherein the pointers and the scales are disposed behind respective viewing windows provided in the indicator.

1 3. Apparatus as claimed in any one of claims 9 to 12, wherein the inner strand of each Bowden cable is connected to the piston of the associated ram.

14. Apparatus as claimed in any one of claims 9 to 12, wherein the inner strand of each Bowden cable is connected to the piston rod of the associated ram.

1 5. Apparatus as claimed in claim 14, wherein the inner strand of each Bowden cable is attached to a bracket fixed to the associated piston rod, said inner strand passing through a tubular guide attached to the cylinder of the associated ram and through a tubular member fixed to said bracket and slidably mounted in the tubular guide.

16. Apparatus as claimed in claim 5, or in any one of claims 6 to 1 5 when appendant to claim 5, wherein each of the hoses accommodating the transmission element is connected to the control valve by means of a T-joint.

17. Apparatus as claimed in any one of claims 7 to 1 6, wherein each of the Bowden cables is provided with an adjustment device for adjusting the length of that Bowden cable.

1 8. Apparatus as claimed in claim 17, wherein each of the Bowden cables is constituted by a plurality of sections, the adjustment device of each Bowden cable being disposed between a pair of adjacent sections of that Bowden cable.

19. Apparatus as claimed in claim 18, wherein each adjustment device is constituted by a coupling member having internally-threaded sockets at each end thereof, said internallythreaded sockets being of opposite hands, and being threadably connected to respective threaded pins arranged at the adjacent ends of the two sections of Bowden cable connected by that adjustment device, the coupling member of each adjustment device being disposed within a sleeve-like rotary member, and being connected thereto for rotation therewith.

20. Apparatus as claimed in claim 19, wherein the rotary member of each adjustment device has a non-circular bore which contains the respective coupling member, said coupling member also having a non-circular cross section.

21. Apparatus as claimed in claim 20, wherein said bore of each rotary member has a generally eiliptical cross section.

22. Apparatus as claimed in claim 20 or claim 21, wherein each of said threaded pins is arranged on a respective slide member, said slide members being secured to the inner strands of the respective Bowden cable sections in such a manner that their axes are off-set from the central longitudinal axes of said inner strands.

23. Apparatus as claimed in claim 22, wherein each of the slide members is disposed in a respective eccentric bore formed in a connection member attaching the adjustment device to the adjacent Bowden cable section.

24. Apparatus as claimed in any one of claims 1 to 5, where each of the transmission elements is a hydraulic transmission line.

25. Apparatus for controlling the position of a mineral mining machine movable along guide means, the apparatus comprising a plurality of hydraulic control rams which are pivotally arranged between the guide means and a support structure for tilting the guide means, each hydraulic control ram having a cylinder and a piston movable relative thereto, the hydraulic control rams being arranged in a plurality of groups, wherein each group of hydraulic control rams is associated with a respective indicator, each of the indicators being connected to each of the rams of its group by a respective transmission element, the apparatus being such that each indicator provides an indication of the position of each of the pistons of the rams of the associated group relative to its cylinder.

26. Apparatus as claimed in claim 25, wherein the guide means is constituted by a guide mounted on a scraper-chain conveyor.

27. Monitoring apparatus substantially as hereinbefore described with reference to, and as illustrated by, Figs. 1 to 5 or Figs. 6 to 9 of the accompanying drawings.