US3438209A - Roof support assembly of the type used on the longwall face of a coal seam - Google Patents

Description

April 15, 1969 K. GREBE 3,438,209

ROOF SUPPORT ASSEMBLY OF THE TYPE USED ON THE LONGWALL FACE OF A COAL SEAM Filed May 27, 1965 Sheet of 9 mun/rap K. GREBE April 15, 1969 ROOF SUPPORT ASSEMBLY OF THE TYPE USED ON THE LONGWALLFACE OF A COAL SEAM Sheet g of 9 Filed May 27, 1965 3,438,209 USED ON THE EAM April 15, 1969 K. GR EBE ASSEMBLY OF THE GWALL FACE OF A COA TYPE Sheet 3 of 9 r m N E w N N R m w n w Q Q 0 T Q Q Q wmw flw wwwmfifi Q l w mw I.- H m IPI i 1 l 4 R mm NM NM @GI N x p R w m p 2 f I G IWWHWI I .lH H x L O m J EIQ B M Q NM W NR sw m mi R a N m a M W r o o H inmnw w QMW J Q/NWQ wwmx %.@I 2 9m $701M WM Vat mm P" 5, 1969 K. GREBE 3, 38,209

ROOF SUPPORT ASSEMBLY OF THE TYPE USED ON THE LONGWALL FACE OF A COAL SEAM Filed May 27, 1965 7 Sheet 4 of 9 nvnw rap April 15, 1969 K. GREBE 3,438,209

ROOF SUPP ASSEMBLY OF THE TYPE USED ON THE L N WALL FACE OF A COAL SEAM Sheet 5 of 9 Filed May 27, 1965 FIG. 76

INVENTOR K. GREBE April 15, 1969 3,438,209 ROOF SUPPORT ASSEMBLY OF THE TYPE USED ON THE LONGWALL FACE OF A COAL SEAM Sheet Q of 9 Filed May 27, 1965 E 8 S T 3% mow wt Qw W2 mm 1 i 1 W W M w mm m H m qGN 6t April 15, 1969 K. GREBE 3,438,209

ROOF SUPPORT ASSEMBLY OF THE TYPE USED ON THE LONGWALL FACE OF A COAL SEAM Sheet 7 of 9 Filed May 27, 1965 MNN GE NNGI www wt April 15, 1969 K. GREBE 3,433,209

ROOF SUPPORT ASSEMBLY OF THE E USED ON THE LONGWALL FACE OF A C SEA-M Filed May 27, 1965 Sheet 8 of 9 INVENTOR.

BY KONRAD GREBE Apnl 15, 1969 K. GREBE 3,438,209

ROOF SUPPORT ASSEMBLY OF THE TYPE USED ON THE LONGWALL FACE OF A COAL SEAM Filed May 27, 1965 Sheet of 9 I N VENTOR.

FIG. 24 koNRAD EQBE A-n'r u c-IV United States Patent 3,438,209 ROOF SUPPORT ASSEMBLY OF THE TYPE USED ON THE LONGWALL FACE OF A COAL SEAM Konrad Grebe, Auf dem Nutzenberg 1, Wuppertal-Elberfeld, Germany Filed May 27, 1965, Ser. No. 459,237 Int. Cl. EZld 11/00 US. Cl. 6145 12 Claims ABSTRACT OF THE DISCLOSURE A roof support assembly for longwall face mining consisting of two frames guided one on the other by means of a guiding element arranged between both frames, such guiding element being connected with both frames in such manner that the frames can move as such, universally in their plane, either in an upward or lengthwise direction within certain limits. This is achieved by interconnecting each of the frames with the guiding element by two organs, one of which enables pivoting to an upward movement and lengthwise displacement, and the other of which affords at least pivoting of the frame in its plane. The connecting organs which afford the pivotal movement of the frame can either be elements shiftable in an upward direction and along the guiding faces of the guiding element in a lengthwise direction, or pivots arranged on the respective ends of the guiding element or pivoting arms arranged on the respective ends. Preferably, double pivotal arms are connected with one another by a pivot of scissors form, one of the arms being provided with a pivot fixed on the guiding element and the other with a pivot fixed on the frame.

The present invention relates to a roof support assembly of the type used on the longwall face of a coal seam formed by two frames each of which consisting from an upper cap abutting to the roof and a lower cap resting on the floor and props connecting these caps with one another, said frames being alternately released and advanced to the coal face and reset in the advanced position.

When the frames of this type of support assembly are advanced alternately one of the frames is released from engagement with the roof and is guided in its advancing movement on the other frame which remains clamped in position between the roof and floor, thus ensuring that the frames always remain parallel to each other in the thrust direction of the support.

A system is already known in which this guiding is achieved by interposing between the roof and the floor struts of the two frames forming the support assembly, a guide member which is longitudinally displaceable in relation to these struts and which engages in connecting members being located on the struts.

While this known system ensures that the frames always maintain their relative parallelism when one or the other is being advanced, it does not take account of the fact that both the floor and the roof struts must be vertically displaceable independently from one another so as to accommodate the changing contours of both the floor and the roof. More specifically it should be possible for such changes in the contour of the floor and the roof to be compensated by raising or lowering one or both ends of the strut on one frame which is then higher or lower, as the case may be, than the corresponding strut on the adjacent frame in the assembly.

:It is also known to provide means in support assemblies of the type described above which allow vertical displaceability or movement in the connecting members which link the frames to the guide member and ensure parallel advancement of the frames. While such a linkage arrangement does permit the struts on one frame to be set at a different level to those on the adjacent frame, it is still necessary for them to run at a level parallel to the guide member, and thus to each other, so that little is gained insofar as the adaptability of the struts is concerned, particularly where irregularities of substantial magnitude are encountered in floor and roof contours.

It is an object of the present invention to eliminate this shortcoming in the above-described known assemblies by enabling random and complete adaptation of the setting of the'floor and roof struts relative to both the floor and roof contours.

According to the present invention there is provided a roof support assembly comprising a pair of relatively movable frames each of which comprises a fioor strut and a roof strut joined by two or more vertical props and a guide member interposed between the roof and/or floor struts and adapted to constrain relative movement between the two frames, wherein each frame is connected to its guide member by two connecting members, one of which allows pivoting movement, longitudinal displacement and vertical displacement of the frame relative to the guide member and the other of which connecting members allows at least pivoting movement of the frame relative to the guide member.

The vertically displaceable and pivoted connecting members for the guide member can, for example, take the form of narrow dog attachments or sliding blocks, which are longitudinally slidable in a dovetail groove running along the entire length of the guide member and which engage in the grooves on the opposite side of the strut, in which position they are both vertically displaceable and pivoted about an axis running transverse to the strut.

At the ends of the grooves limit stops are provided to prevent the escape of the sliding blocks. If the two ends of the guide member are not connected with the strut it is then necessary to provide a second slotted guideway thus ensuring accurate parallel guidance.

In a modification of the invention the connecting members are in the form of magnets, which are vertically displaceable and pivoted on the strut about an axis running transverse to the strut, the pole surface of the magnets being parallel to the sidewall of the guide member, with which they are in direct holding contact and which, in this embodiment can be formed without any rail or groove.

As the guide member moves, its sidewall is moved past the magnets, which offer only a comparatively minor resistance to this longitudinal displacement, but any tendency to complete separation is subjected to comparatively high resistance.

In this modification at least the guide member which is interposed between the floor struts of the support assembly can be designed as a thrust cylinder. For this purpose the guide member is provided with two superposed or adjacent cylindrical bores extending longitudinally through the guide member and in which the cylinder pistons are movable in opposite directions.

The length of the guide member corresponds to the spacing of the vertical props in one of the frames. Owing to its restricted length the guide member does not, under any circumstances, extend beyond the struts of the two frames comprising the support assembly but will nevertheless contact the struts of both frames over a sufficient length to ensure accurate guidance when the frames are moved. The cylinder piston rods are pivoted on the frames, preferably by means of a hinge pin mounted transversely on a strut, so that while the struts are held parellel to the piston rods and the guide member in the direction of movement of a forward stroke they are still able to function as vertical props in relation to the latter.

According to a further embodiment of the invention the vertically-displaceable seating of the linkage system is not incorporated in parallel guides, as is the case with the above-described embodiment, being instead of pivoted at the free ends of hinged arms are mounted pivotally on a horizontal axis on the strut and both longitudinally displaceable and swivelable in relation to the guide member. The vertical position of the linkage system or connecting members is thus determined in each case by the angle formed by these swivel arms in relation to the strut. In this case, also, where appropriate, the connecting members lie above the floor struts or below the roof struts, as the case may be. In no case, however, does the free end of the swivel arm extend beyond or below the longitudinally displaceable guide member to which it is attached, thus ensuring that the space delineated by the prop on the one side and the actual position of the longitudinally displaceable guide members on the other is neither reduced nor impaired.

Particular advantage is gained, if, in accordance with a further feature of the invention, the swivel arms referred to above are provided with a spring mounting, such as torsion bars. Where appropriate, this spring mounting enables the mutual parallel guidance of the two frames incorporated in the support assembly to be altered should it prove necessary for any reason to change the thrust direction of the support. The springs should have sufiicient tensile strength to ensure that considerable force is required to bring about any change in the thrust direction of the support assembly and also to prevent the latter from reacting to any forces normally anticipated in dayto-day operations. Thus the thrust direction of the support assembly can be changed only by deliberate application of a powerful wedging or spreading force. This embodiment of the invention provides a particular improvement upon known methods for changing the thrust direction of a support assembly inasmuch as it dispenses with the necessity for relieving the pressure on each individual prop. As is quite generally known it can, under some circumstances, be of considerable importance for the etficient functioning of a mechanized movable support assembly for either of the two frames embodied in the assembly to remain propped in position while relevant aljustments are made to its counterpart where it is necessary to change the thrust direction.

Particular advantages can be gained if, in yet a further development of the invention, the connecting elements between the struts and the telescopic guide member are constructed not merely as single swivel arms but by means of a joint, this being most effectively achieved by means of a pivot pin.

The scissor shape formed by the double swivel arms is closed in normal position and opens as soon as the strut sinks or adopts an inclined angle relative to the guide member. The main advantage of this arrangement lies in the fact that, when the strut adopts an angular position relative to the telescopic guide member the points at which the two members of this swivel arm are pivoted to their appropriate parts cannot be displaced in relation to each other in the thrust direction of the frame.

This double swivel arm construction While it can be employed on other embodiments of the invention can be combined in a notably advantageous fashion with a telescopic unit adapted for this purpose and which comprises two mated tubes which slide appropriately within each other. Each of the struts located at either side of the telescopic unit is assigned to one of the two tubes and connected therewith by the appropriate connecting member, this being vertically displaceable relative to the telescopic unit and/or swivelable relative to the strut, at least two such connecting members being located on each strut. One of these connecting members is fastened in a longitudinally fixed location on the tube assigned to the strut, thus ensuring that axial movement of the tube transmits a similar thrust to the strut, or vice versa. The sec- 0nd (and where applicable, the third) vertically displaceable connecting member should then serve merely to ensure an adequate degree of lateral guidance for the struts, which, owing to the vertical displaceability of the connecting members, are able to adopt an angular position in the vertical plane.

If, for example, the connecting member is a singlearmed swivel arm or is constructed in such a manner that inclination of the strut causes longitudinal displacement of one of the two points at which it is pivoted with the telescopic unit, the additional connecting member will have to be attached to a longitudinally displaceable mounting on the guide member, e.g. in a dog attachment. In turn this produces the particular advantage that the sliding dog is carried directly on one of the tubes in the telescopic unit, thus dispensing with any necessity for supplementary guidance. The guidance is normally applied to the outer tube or sleeve, whereby the sliding dog on the connecting member displaces the strut assigned to the inner tube over almost the entire length of the sleeve in conjunction with extension or contraction of the telescopic unit, while the strut on the sleeve tube is displaced only marginally at the end of the tube by its relevant sliding dog attachment. The reciprocal action of the sleeve tube has no effect whatsoever upon the motion of this sliding dog in its mounting, since strut and sleeve tube movement are simultaneous. Only if the strut adopts an angle relative to the sleeve tube during this movement is there a marginal movement on the part of the dog, but this can quite easily be deflected to the inner tube by appropriate shortening of the sleeve tube.

Each telescopic unit can also consist of a double set or arrangement of appropriate tubes. In such cases each of these assemblies is attached to one of the two struts and each strut then is joined to its appropriate assembly with the aid of a connecting member mounted in a longitudinally fixed seating on the outer tube which forms the sleeve of the unit and by at least one additional connecting memher which is vertically displaceable and is also fastened to the appropriate sleeve tube or to a connecting member which is longitudinally displaceable along the sleeve tube. It is thus necessary to make identical provision to those outlined in the foregoing text, merely simplified by dispensing with the attachment of the one strut on the inner tube. When the telescopic arrangement is extended, the sleeve tube of the one assembly must always move in conjunction with the inner tube of the other assembly, so that the two assemblies must be interconnected in inverse relationship to each other. This ensures mutual conformity of movement of the strut on the one hand and the sleeve of its appropriate tube assembly on the other, following the identical pattern of behaviour to the struts and appropriate tubes involved in a single assembly of telescopicallydisplaceable tubes.

The support is moved in the conventional manner releasing one of the two frames and subjecting the released frame to a force which pushes it forward, the released frame being guided during its movement on the fixed frame of the support assembly. Since the frames can be moved forward by one complete prop space in each instance, this force can, for example, be exerted by means of a rope led around the props in the pair of support frames and pulled by a winch located at the end of the frame assembly to be moved in longitudinal direction of the coal face. The effectiveness of the force to which the rope is subjected thereby is of little consequence in the region of those frame pairs which have already been moved, since the rope runs in an almost straight line at that point. Since, as viewed from the winch, one frame is moved after the other in consecutive sequence, the rope grips the frame to be moved with full force, or almost full force, and the pronounced angles of the rope in the area of frames which have not yet been moved has no adverse effect upon overall efficiencyor, where it is necessary to move several frames simultaneously, this arrangement causes the first frame to be pulled forward automatically faster than the second and third frames, a situation which can only be described as desirable, especially for pushing forward a conveyor supported on the frames or a backfill channel suspended from the frames, or similar. The rope to be used for moving the frames into the next stratum must naturally be led in front of the props of those frames which have been moved forward and behind the props of those frames still to be moved.

If the assembly is to be moved with the aid of thrust cylinders particular advantages can be gained by incorporating the thrust cylinders in the sliding guide member by designing each of the two mutually displaceable tubes as a ram cylinder, the piston rod of which is attached to the outer tube which functions as the sleeve.

In this case the sleeve tube represents a desired measure of protection for the piston rod, on the one hand by virtue of the fact that the forces which arise and are exerted in other than axial directions on the piston rod, thus subjecting the piston rod to flexural stress and the inner walls and gaskets of the cylinder to undesirable pressures, are absorbed by the sleeve tube which is located on the outer wall of the cylinder and on the other hand by virtue of the protection afforded the piston rod against any possibility of foreign bodies being deposited on it and against jamming between the member connecting the piston rod with its appropriate strut on the one side and the cylinder on the other when the piston is retracted. Specifically this form of protection is achieved if the sleeve presents an uninterrupted surface rather than being slotted. If the strut assigned to the cylinder is to be connected at both ends by guide members secured on the cylinder, this necessitates a fixed mounting on the cylinder of a further tube enclosing the sleeve tube which is slidably connected with the piston rod. This tube may, in turn, be slotted in order to permit the connecting members to engage through the slot between the displaceable sleeve tube and the appropriate strut.

If, as is preferable, the connecting members are double swivel arms fundamentally of the type described above, the longitudinal displaceability of these double swivel arms is effected by their attachment to a tube which, in turn, slides on another tube. Thus if two connecting members are fastened to the same tube, this is equivalent to the dogs common to the two connecting members assigned to the same strut.

Where such double-armed swivel arms are located as connecting members on both ends of the strut this enables a flexible resistance to be achieved to the various reciprocal angling-off movements of the strut and thus to reduce these movements of the strut and thus to re duce these movements to the degree found to be necessary in each case when advancing a frame. The swivel arms are positioned so that their ends, provided with the joint between both arms, are opposed to each other and interconnected by a draw spring. This draw spring engages appropriately on the horizontal pivot pins of the swivel arms. This draw-spring may, however, be replaced by torsion springs located on one axis of the swivel arms and braced against a support in such a manner as to hold the arms parallel to the struts. It may also be expedient to prevent any undesirable deflection movements when the frames are being advanced. This can be achieved with the aid of blocking devices which limit the angles of the swivel arms relative to the struts and/or relative to the guide member, as well as, where appropriate, angling of the two members of a swivel arm in relation to each other. Finally the draw spring has the important advantage that when the strut is to be moved forward by the guide members or member this movement is transmitted always from the front end of the advancing member via the swivel arm fastened to it and the drawspring to the swivel arm fastened to the rear end of the other member, thus ensuring that the motion is always a pulling rather than a pushing action. Accordingly the drawspring must be of sulficient strength to ensure that it cannot be pulled to an excessive length by the shearing forces to which it may be subjected. Notwithstanding, the unimpaired movability of the joints which interconnect the ends of the double swivel arms still permits the struts to swivel relative to the guide member, as a result of which there is no displacement of the parallelogram.

Preferred forms of the invention will now be described with reference to the accompanying diagrammatic drawings in which:

FIGURES 1 and 2 show, merely to illustrate the field of application of the invention, horizontal sections through a coalface propped with support assemblies in various stages of advance;

FIGURE 3 is an enlarged cross-section on the line IIIIII of FIGURE 4, but leaving out the roof struts;

FIGURES 4 to 6 are plan views of the frames of a support assembly, but omitting the roof struts, in three relative positions;

FIGURE 7 is a section on the line VII-VII of FIG- URE 6, through the guide member 10;

FIGURES 8 to 10 show the roof struts in positions corresponding to FIGURES 4 to 6'; I

FIGURES 11 and 12 are sections on the lines XI-XI and XIIXII respectively in FIGURE 9, but showing the roof struts of both frames in the support assembly angled vertically in relation to each other; FIGURE 13 is a plan view of a support assembly in which the longitudinally displaceable guide member is designed to accommodate the ram cylinder serving to advance the assembly when in start position.

FIGURE 14 is a plan view showing the assembly of FIGURE 13 on a reduced scale leaving out the roof struts and showing the floor struts in a different relative position;

FIGURE 15 is a side view of the assembly of FIG- URES 13 and 14 accommodating a step in the floor of the seam;

FIGURES 16 to 19 are plan views of four pairs of support frames each incorporating a different embodiment of a telescopic assembly;

FIGURE 20* to 22 are enlarged plan views of the advancing cylinders or rams associated with the telescopic assemblies of FIGURES 16, 17 and 18 respectively;

FIGURES 20A and 20B are opposite end views respectively of the structure shown on FIGURE 20;

FIGURES 21C and 21D are opposite end views respectively of the structure shown on FIGURE 21; and

FIGURES 22E and 22F are opposite end views respectively of the structure shown in FIGURE 22.

FIGURE 23 is a perspective exploded view of one of the roof support assemblies, including the floor strut, the props and guide member, and the means in which the elements are connected and cooperating in accordance with the structure shown on FIGURE 21; and

FIGURE 24 is a perspective exploded view of the parts shown on FIGURE 5.

As can be seen from FIGURE 1 and 2 a support assembly comprises two groups of frames, the frames in the first frame group having vertical props 3, 3, 3 and 4, 4', 4 which are interconnected by roof struts 1, 1', 1" projecting on the coalface side and by floor struts 11, 11 extending from prop to prop. The frames in the second group are formed by props 5, 5', 5" and 6, 6', 6" roof struts 2, 2, 2" and the floor struts 12, 12'.

Between floor strut -11 of a frame in the first group and adjacent floor strut 12 of a frame in the second group which is assigned to the same support assembly a guide member 10 is interposed, and a similar but simplified guide member 30 (see FIGURES 11 and 12) is interposed in similar manner between the roof struts 1 and 2 of the same assembly. The sidewalls of the guide member 10 border on the upper and/or lower flange of the struts 1, 2, 11, 12, which, for example, can be in the form of double-T shaped girders, even if the struts are included in a vertical plane or displaced longitudinally in relation to each other. In addition both sidewalls of the guide member are provided with swallowtail grooves The guide member 10, the length of which corresponds to the distance between the props 3 and 4 of a frame in the first group, has two adjacent cylindrical bores 20, extending longitudinally of the guide member in one of which is housed a piston rod 21 which slides toward the coalface While the other houses a piston rod 22 which slides out toward the backfill side. The piston rod 21 has an articulated head 31 which is connected by a hinge bolt 41 to the floor strut 11, 11', and the piston rod 22 is connected in the same manner by an articulated head 32 and hinge bolt 42 to the floor strut 12 on the other frame.

In FIGURE 4 the upper flange of the strut 12 in the region of this articulated joint, which can, for example, be of a hinged type, has been left out in order to illustrate a practical embodiment of the articulated joint.

When advancing through the coal stratum the frame bearing floor strut 11 is first released so that it is supported by the guide member 10 which is attached to the stationary floor strut 12 and is then advanced by pushing out the piston rods 21 and 22 into the position shown in FIGURE 5. The articulated bolts 41, 42 serve as bearing points for the guide member 10, and the sidewalls of the guide member 10' and grooves 10' guide the floor strut 11 on one side of the guide member 10 while the guide member 10 is itself guided on the other side in similar manner by the floor strut 12. On the struts, such as 11 and 12, sliding blocks 51, 52 are arranged to slide vertically in guides 71, 72. Furthermore, the blocks 51, 52 are shiftable in a lengthwise direction in grooves 10 of the guide member 10. By this arrangement, the parallel movement of the struts 11, 12 is ensured while the position of the struts is altered in a lengthwise direction in the course of advancing and in a vertical direction as a result of alterations or changes in the contours of the roof or floor. When the forward frame is settled in the advanced position shown in FIGURE 5 the floor strut 12 is released and pulled into place by drawing in the piston rods 21, 22, into the position shown in FIGURE 6.

FIGURES 8, 9 and 10 show the roof struts 1, 2, in corresponding positions to FIGURES 4 to 6 with a simplified guide member interposed between them. The length of guide member 30 corresponds to the length of the floor strut 11 and a groove 30' in the guide member 30 has a stop at either end which prevents the sliding blocks 61, 62 from escaping. Two sliding blocks 51, '52 are provided on each side of the guide member 30 sliding in guideways 71, 72 on the struts 1, 2.

In FIGURE 3 the sliding block 52 is shown in its normal position, that is the position when the ground is level. The sliding block 52 is mounted pivotally on the guide member 10 by means of cylindrical bolt 82 which is a sliding T-head 62 and which is held on the link 52 by a rivet head 92. A similar slotted guide member and sliding block is shown in FIGURE 12. FIGURE 11, on the other hand, illustrates a circular sliding block 61 which can pivot in the groove 30 and which is therefore connected rigidly to the slotted guide 51. FIGURES 11 and 12 also show the position which the slotted guides 51, 52 assume in their guideways 71, 73 when the struts 1, 2' are inclined upwardly towards the centre of the support assembly, in the shape of a roof, for instance because the floor and the roof rises in the direction of props 4' and 5' and the props 3 and 6 stand in a depression.

In FIGURES 13 to 15 the roof struts are also designated as 1, 2, the floor struts as 11, 12, the props as 3, 4, 5, 6, the longitudinally displaceable guide members with their two superposed thrust cylinders as 10 and the piston rods of these two cylinders as 21 and 22. The

longitudinally displaceable guide members 10 are pivoted on struts 2, 12 of one frame by means of a swivel arm 25, 15 and via the telescopic piston rods 22 with the aid of a pivot joint 42. They are pivoted on struts 1, 11 by a swivel arm 24, 14 and via the piston rod 21 by a pivot joint 41. The pivot joints 41, 42 are not displaceable longitudinally in the direction of the struts, as it would otherwise be impossible to telescope the two frames to the same extent that piston rods 21, 22 can be telescoped.

Consequently, the pivot joints 41, 42 must either be located in a stationary position on the struts or, as shown in the figures be seated in a guide member 51, 52 which is slidable in a guideway vertical to the longitudinal plane of the struts or along the line formed by the props 3, 6, the guideways 71, 72 allowing vertical, and only vertical movement of the pivot joints 41, 42.

FIGURE 15 shows the manner in which as a result of the end points of the longitudinally displaceable guide member 'being movable vertically when the assembly is being advanced, it is possible to overcome a step in the floor without difficulty. In order to keep the guide members as close as possible to the height of the struts, a limit to the vertical movement of the end part of the guide member should preferably be marked before commencing the advancing process, for example by pegging, or they should be subject, within the parallel guideways 71, 72, to the pressure of a spring acting in the appropriate direction. In FIGURE 15 the upper guide member 10 which is attached to the roof struts 1, 2 is shown in a region of the roof where the contours are normal. In the region of floor struts 11, 12, the appropriate guide member 10 in order to overcome the step either adopts the inclined position illustrated or its entire length is aligned on a level with the floor strut 11. It can also assume a position somewhere between these two positions. If the two end points of the lower guide member 10 are brought into the highest possible positions permitted by the parallel guideways 71 and 72, it is then possible to surmount steps of about double the height of that shown. In a corresponding manner the assembly can also be advanced through troughs and over saddles.

The angular position of the swivel arms 14, 24 and 15, 25 which are pivoted about axles 34 and 35, respectively, which are located on the appropriate struts in relation to the strut and guide member, is determined by the position of the guide member 10, in the longitudinal grooves 10' of which slide the connecting members 44, 45 located on the free ends of the swivel arms. The connecting members 44 and 45 are in turn pivoted in relation to the swivel arms 14, 24 and 15, 25 respectively or in relation to the guide members 10. If the swivel arms 14, 24 and 15, 25 are provided with a spring mounting the frame having struts 1, 11 in the region of prop 4 and the frame having struts 2, 12 in the region of prop 5 are supported to a certain extent by the longitudinally displaceable guide member 10. By this means it is possible to influence the thrust direction of the assembly and to facilitate this the hinge pins 41, 42 are shaped spherical to a suificient extent to allow the amount of play or universal movement required.

FIGURES 16 to 23 illustrate three further embodiments of the invention in which the connecting members between the struts and their appropriate cylinder are modified, FIGURE 16 corresponding with FIGURE 20, FIGURE 17 corresponding with FIGURES 19 and 21 and FIGURE 18 corresponding with FIGURE 22.

In FIGURE 16 the floor strut 111 is connected to an inner tube and the floor strut 112 is connected to a sleeve tube which slides telescopically on the inner tube 120. FIGURE 20 is on a larger scale and shows the floor strut 112 drawn up to the strut 111 and also shows a thrust imparting cylinder in place of the inner tube 120. In the embodiment illustrated in FIGURE 20 the sleeve 130 is attached to an end of the piston rod of the thrust cylinder 170, so that it is pulled in along the cylinder when the piston is withdrawn and pushed out along the cylinder when the piston is expelled, since in this case the sleeve 130 is attached to the strut of the fixed frame, the cylinder is pressed out of the sleeve.

At one end of the inner tube 120 (of cylinder 170) there is a lug on which a plate 151 is pivotally mounted by a pin 141, the plate being vertically displaceable in a parallel guideway 171 on the strut 111. The sleeve tube 130 has a recess at one end in which it accommodates the afore-mentioned lug when the telescope is collapsed (as in FIGURE 20) or it is shortened appropriately around the whole of its circumference (as in FIGURE 16). The strut 111 is also connected by a single-member swivel arm 124 to the sleeve tube 130. The swivel arm 124 is attached at one end to the strut 111 on a pin 134 rotatable about its own axis. Two torsion springs 137 and 138 are fastened to the pin 134, one of the springs being braced against a support when the pin rotates in one direction and the other spring being braced against the support when the pin rotates in the opposite direction, a suitable support being, for example, a flange of the strut. While this is not discernible from the drawing both springs are biased and locked. At the other end the swivel arm 124 pivots on a bearing 144 and is secured to a dog attachment 154, the latter partially encircling the sleeve tube 130 on which it is longitudinally displaceable.

The strut 112 is linked to the guide member in a similar manner via a connecting member 142, 152 on the sleeve 130 which is vertically displaceable but not longitudinally displaceable in a guideway 172 on tht strut and by a single-member swivel arm 125 which is attached at one end to thestrut 112 and at the other end to the telescopic guide member by a dog attachment 155 Which either slides on the inner tube 120 (in the case of the shortened sleeve tube shown in FIGURE 16) or on sleeve tube 130 (in the case of a sleeve tube which is recessed on only one side as shown in FIGURE 20).

The tube arrangement of FIGURES 17 and 19 is best explained on the basis of FIGS. 21C and 21D. In this embodiment the sleeve tube 130 slides on inner tube 120 formed by the thrust cylinder 170. To permit the inner tube 120 or cylinder 170 to be connected at both ends with its appropriate strut 111 without having to slot the sleeve tube 130, the inner tube 120 (of cylinder 170) is connected firmly with a slotted tube 140 which, in turn, partially encircles the sleeve tube 130 clawfashion. This duplication of the guidance for the sleeve 130 is of particular advantage where the inner tube is in the form of cylinder 170, the piston rod of which is to be protected from damage. The arrangement can also be simplified by dispensing with the tube 120 altogether in which case the tube 130 is the inner tube upon which the slotted tube 140 slides.

Axles 192 are located on extensions of tube 140 and the tube 130, opposite and in alignment with axles 191 which are located on the struts 111 and 112. Arms 193, 194, 195, 196 are pivoted on the axles 191 and arms 193', 194, 195', 196' of the two-member swivel arm are pivoted on axles 192. Between the arms 193, 193' and the arms 194, 194', a pivot joint 197 is interposed. In normal position the axles 191 and 192 and thus arms 193 and 193, and arms 194, 194 etc., are at the same level but if the tubes 140, and 130, fall in relation to the struts 111 and 112 respectively, or if they rise, the axles 191 and 192 separate accordingly and the two- member swivel arms 193 and 196 open scissors-fashion at the joint 197, this opening movement being counteracted by drawsprings 198.

In FIGURES 18 and 22 the sleeve tube 160 connected to the strut 111 is longitudinally slidable on an inner tube 150' (the thrust cylinder 180), while the sleeve tube 160 connected to the strut 112 is longitudinally slidable on the inner tube 150 (the thrust cylinder 180), so that the sleeve tube 160" connected to the strut 111 is connected rigidly with the inner tube 150 (thrust cylinder 180) on the assembly connected to the strut 112. In the 7 same manner the reverse applies, the sleeve tube 160 being joined rigidly with inner tube (thrust cylinder 180'). The connecting members between the sleeve tube and the strut 111, between sleeve tube 160 and strut 112, are of identical construction to those shown in FIGURES 2 and 6, but can equally well be constructed in the form illustrated in FIGURES 16 and 20.

It is not necessary to deal in detail with the process whereby the support assemblies are moved with the aid of the thrust cylinders and respectively. FIGURES 16 to 19 illustrate the manner in which this-is carried out using a rope, the rope being led respectively around the coalface side of prop 104 and around the backfill side of prop 106. Rope traction is achieved with the aid of a winch set up at the lower end of the coalface, with respect to the group of frames to which the rope is at tached. After releasing the frame bearing strut 112 of FIGURE 18, the frame is pushed forward until prop 105 reaches the row containing prop 103 and prop 106 reaches the row containing prop 104. The frame is then settled anew and the frame bearing strut 112 of FIGURE 17 is released and advanced appropriately.

In the next seam a rope is used in the appropriate manner, being laid around the coalface side of prop 105 in each case and around the backfill side of prop 104, Both ropes can be carried permanently on the support frames, each being operated by its own winch set up at the lower end of the appropriate frame group and wound back on to a winch mounted on the upper end of the frame group after the group has been advanced. In this case it is necessary to the upper winch to be blocked while the rope assigned to it is wound on to the lower winch, while on the other hand the upper winch to which the other rope is assigned must permit the rope which it carries to be unwound. The frames in the first pair in the group are not advanced by the rope but, for example, by the thrust cylinders.

What I claim is:

1. A roof support assembly comprising a pair of relatively moveable frames each of which comprises a floor strut and a roof strut each joined by two vertical props, guide members interposed between the respective floor struts and roof struts of each said frame, extensible means forming a part of each guide member, a pivotal connection between each extensible means and the respective floor and roof struts for enabling relative pivotal movement of the respective frame and guide member, and operative connections between each guide member and the respective floor and roof struts of each frame, each operative connection including a pivotal joint to enable rocking movement of the particular strut relative to the respective guide member, a joint to enable longitudinal shifting of each frame relative to the respective guide member, and a joint to enable vertical movement of each frame relative to the respective guide member.

2. A roof support assembly comprising a pair of relatively moveable frames, each frame having a floor strut and a roof strut, two vertical props joining the floor and roof struts of each frame, a guide member interposed between said floor struts, saide guide member comprising two relatively shiftable parts, means for rockably connecting one shiftable part to one floor strut, means for rockably connecting the other shiftable part to the other floor strut, means for slideably connecting said guide member to one floor strut enabling relative vertical movement thereof, and means for slideably connecting said guide member to the other floor strut enabling relative vertical movement thereof.

3. A roof support assembly as claimed in claim 2, in which said rockable connection at each outer end of said shiftable parts comprises a trunnion attached to the respective frame at a point spaced in the vertical direction from the strut with which such shiftable part is associated.

4. A roof support assembly as claimed in claim 2, in

which at least the guide member interposed between the floor struts is telescopic and constructed as a double thrust cylinder having pistons acting in opposite directions.

5. A roof support assembly as claimed in claim 2, in which each frame is attached to its associated slidable part of the guide member by two double swivel arms each comprising two links pivotted together at one end and attached at their other ends by trunnions respectively to the guide member and the frame and being adapted to pivot in scissors fashion about the axis of the pivotted ends.

6. A roof support assembly as claimed in claim 5. in which the double-swived arms connecting each frame to the guide member are located between and in alignment with the guide member and the frame with the axes of the pivotted ends of the swivel arms on each side of the guide member adjacent one another and interconnected by a spring.

7. A roof support assembly as claimed in claim 6, in which the swivel arms are permanently biassed into parallel relation with the struts of the associated frames by springs anchored to a support on the pivotal axes of the swivel arms.

8. A roof support assembly as claimed in claim 6, in which the swivel arms are blessed in a direction transverse to the length of the struts of the frames.

9. A roof support assembly comprising a pair of relatively moveable frames, each of which comprises a floor strut and a roof strut, two vertical props joining each floor strut and a roof strut, a guide member interposed between the floor struts of the two frames, the guide member in the form of two parts slideable along each other, each of which comprises a tube and a spaced parallel extending sleeve, means for interengaging the tube and sleeve on one sideable part with the sleeve and tube on the other sideable part, and means for pivoting each slideable part to a frame, said pivoting means including two connecting members enabling relative vertical movement between the slideable part and the frame.

10. A roof support assembly as claimed in claim 9, in which the sleeve is slotted and the connecting members attached to the tube project through the slot.

11. A roof support assembly as claimed in claim 10, in which the sleeve is an enclosed tube having a recess at one end accommodating the connecting member which attaches the inner tube directly and non-displaceably to the associated frame, the other connecting member on the associated frame being mounted on a dog attachment which is longitudinally and vertically slidable on the sleeve or inner tube.

12. A roof support assembly as claimed in claim 11, in which the sleeve which is in the form of an enclosed tube is encased by a non-displaceable slotted tube attached to and coxial with the inner tube, the inner tube being constructed and acting as a thrust cylinder and the connecting members between the sleeve and its associated frame projecting through the slot in the non-displaceable tube.

References Cited UNITED STATES PATENTS 1,594,921 8/ 1926 Barnett 6145 3,169,377 2/1965 Hoifmann 6145 3,197,965 8/1965 Lee et a1. 61-45 3,197,966 8/1965 Arnott 6145 3,241,323 3/1966 Grisebach 61-45 FOREIGN PATENTS 968,117 8/ 1964 Great Britain. 1,091,525 10/1954 France.

970,540 10/ 195 8 Germany. 1,156,037 10/ 1963 Germany. 1,159,884 12/ 1963 Germany. 1,166,127 3/1964 Germany.

DENNIS L. TAYLOR, Primary Examiner.

DAVID J. WILLIAMOWSKY, Assistant Examiner.

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