US3490244A

US3490244A - Support

Info

Publication number: US3490244A
Application number: US690856A
Authority: US
Inventors: Karl M Groetschel
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-08-29
Filing date: 1967-12-15
Publication date: 1970-01-20
Anticipated expiration: 1987-01-20
Also published as: BE652266A; NL6410054A

Description

'K. M: GROETSCHEL.

Jan. 20, 1970 SUPPORT 3 Sheets-Sheet 1 Original Filed Aug. 25, 1964 471 A w W m :lfi R C T v Ne I E V O r Aw y m M m .m f M w K Jan. 20, 1970 K. M. GROETSCHEL 3,490,244

SUPPORT Original Filed Aug. 25, 1964 3 Sheets-Sheet a N w s w z? w #2 #4 HQ 9 WVENTQR Marl GHQ @meiscliea BY a" I 62 Jan. 20, 1970 K. M. GROETSCHEL 3,490,244

SUPPORT Original Filed Aug. 25, 1964 3 Sheets-Sheet 3 //J 1/! 58 lo M #9 JNVENTOR United States Fatent O 3,490,244 SUPPORT Karl M. Groetschel, Stolzestrasse 44, Bochum, Germany Application Aug. 25, 1964, Ser. No. 392,002, now Patent No. 3,371,901, dated Mar. 5, 1968, which is a continuation-in-part of application Ser. No. 322,606, Nov. 12, 1963. Divided and this application Dec. 15, 1967, Ser. No. 690,856 Claims priority, application Germany, Aug. 29, 1963, G 38,575; June 29, 1964, G 40,953; Austria, May 14, 1964, A 4,234/ 64 Int. Cl. E21d 23/18 US. Cl. 61-45 18 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a roof support for a mine working which includes a bottom structure, a plurality of upwardly extending props carried thereon, an upper structure carried by the props, and a traction means for advancing the support wherein the direction of advancement of the support is determined by forming at least one of the bottom and upper structures in two parts having lateral clearance and capability of relative angular movement in a plane parallel to the floor or roof of the working, and providing an angularly swivellable guide element to determine the angular relationship of one of these parts to the other, or providing, in the case of the bottom structure, a transversely movable guide member operating in combination with a fixed guide member to define a guideway which diverges to the left or to the right of a longitudinal reference axis or is parallel to the latter, one of the parts of the bottom structure including a guide rod movable along this guideway.

CROSS REFERENCES TO RELATED APPLICATIONS This application is a division from my application Ser. No. 392,002, filed Aug. 25, 1964, and now patent No. 3,371,901, which in turn is a continuation-in-part of application No. 322,606, filed Nov. 12, 1963, and now Patent No. 3,425,229.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to roof supports primarily for use in underground mine workings of the kind comprising a bottom structure for resting on the floor of the mine working, a plurality of upwardly extending props carried on said bottom structure, an upper structure carried by the props for engaging and supporting the roof of the mine working, and traction means for advancing the support. Such supports are hereinafter referred to as being of the kind specified.

Self-advancing roof supports of the kind specified are required to be advanced along predetermined directions to enable same to be maintained in respective proper positions along the length of a coal face.

The main object of the present invention is to provide a support incorporating an improved means for controlling the direction of advancement.

Description of the prior art In my co-pending application 322,606, now Patent No. 3,425,229, I have described and claimed a self-advancing roof support of the kind specified wherein the support includes a forwardly movable part, guide means for determining the direction of movement of said movable part relative to a horizontal, longitudinally extending, reference axis of the supporting device, such guide means having co-operative surfaces disposed respectively on said forwardly movable part and on a co-operative part of the supporting device, and defining paths diverging respectively to the left and to the right with respect to the reference axis, and movement of said movable part being effected by said traction means in a forward direction selectively along a path parallel to the reference axis or along one or the other of said divergent paths.

In said co-pending application, however, the guide means which provide for selective forward movement along one or the other of said divergent paths or along a path parallel to the reference axis were incorporated in the bottom structure of the support.

In certain severe conditions where guidance is required as to the direction of advancement of the support, there is a possibility of relatively movable parts of the upper structure failing to conform to the guide path defined by the guide means provided in the bottom structure.

A specific object of the present invention is to ameliorate this position.

SUMMARY OF THE INVENTION According to the invention a mine roof supporting device comprising a bottom structure, a plurality of upwardly extending props thereon, an upper structure carried by the props, and traction means for advancing the support, includes an improvement wherein the upper structure comprises a first part and a second part interleaved laterally with each other and having relative lateral clearance, the second part projects forwardly of the first part at least upon advancement of the support by said traction means, guide means are provided at the level of said upper structure defining the lateral position and path of advancement of said second part of the upper structure relatively to a reference axis extending medially and longitudinally of the support, means are provided for adjusting said guide means to vary the angular relationship in a plane parallel to the roof between said path and said reference axis.

Further, a mine roof supporting device comprising a bottom structure, a plurality of props carried thereon, and an upper structure carried by the props for supporting the roof, incorporates in accordance with the invention the improvement comprising a forwardly movable part free from any of said props, the support includes guide means for determining the direction of movement of said forwardly movable part relatively to a horizontal, longitudinally extending, reference axis of the support, such guide means having co-operating surfaces disposed respectively on said forwardly movable part and on a cooperative part of the bottom structure and defining paths diverging respectively to the left and to the right with respect to said reference axis, said traction means is op-v BRIEF DESCRIPTION OF THE DRAWINGS Additional objects and advantages of the present invention will become apparent upon consideration of the following description when taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a side diagrammatic sectional view of a three-leg support assembly having a single base element;

FIGURE 2 is a plan view of the structure illustrated in FIGURE 1;

FIGURE 3 is a view partly in section, taken substantially along the plane defined by reference AA of FIGURE 1;

FIGURE 4 is a horizontal sectional view of a three-leg support assembly of the form illustrated in FIGURE 1 and having an advancing device and a direction control means;

FIGURE 5 is a sectional view taken substantially along the plane defined by reference line BB of FIGURE 4;

FIGURE 6 is a schematic side elevational view of a further embodiment of an assembly having two base elements which can be advanced alternately;

FIGURE 7 is a plan view in which only the upper structure elements of the entire assembly of FIGURE 6 are shown;

FIGURE 8 is a plan view of the assembly illustrated in FIGURE 6 but with the upper structural elements removed;

FIGURE 9 is a plan view partly in section of an embodiment of the form illustrated in FIGURE 6 and having an advancing and direction control means.

GENERAL CONSIDERATION OF THE INVENTION The invention comprises the feature of providing the novel support assemblies with a moving device which is particularly suited for these support assemblies. This moving device may include a special direction-giving device so that it is possible to vary and/or correct the travelling direction of the assemblies during the moving thereof. This direction control device is, for example, preferably a cylinder-piston unit, spindle or the like which is effective upon a guiding device in transverse direction. This guiding device includes a yoke which is directed at right angles .to the longitudinal direction of the trestle or assembly. This yoke can be connected to the mining machine or conveying means or to a partial assembly which is movable by itself and forms the point of engagement for the advancing cylinders or the like of the moving device or also for the direction control device or portions thereof. This yoke carries at least one guide rod or the like which is connected rigidly and at right angles with the yoke and extends slidably and with play into a chamber of the assembly or partial assembly respectively.

Such guide rod or rods are pivotable about a fixed point lying in one of the two end regions of the bottom structure. If desired the same or a similar pivoting point is provided at the upper structure of the support device which point makes possible a lateral pivoting of the longitudinal girder which is approximately parallel to the pivoting direction of the guiding device provided in the lower region of the support assembly. This lateral pivoting is made possible particularly if a longitudinal girder which engages the frame-like upper structure is carried by the support of a partial assembly which can be moved by itself.

If, as the direction control device, not only one but a pair of cylinder piston units are used which can be put under pressure together or also separately and of which one is effective at one end and the other is effective at the lower end of the transverse yoke of the guiding device, an additional cylinder piston unit or the like which would be effective in the transverse direction upon the guiding device can be dispensed with in most cases.

In a further construction of the latter feature of the invention, the transverse yoke of the guiding elements which slide in one of the two partial assemblies is coupled to the other separately movable partial assembly. This coupling is done by means of an annular or framelike body which is detachably but firmly connected with the transverse yoke of this guiding body. This annular or frame-like body encompasses the lower zone of this separately movable partial assembly so loosely that movements of both components in vertical direction with respect to each other are possible, but too extensive a tilting motion of the encompassed assembly in any direction is prevented.

This ararngement makes it possible to eliminate difficulties (break of the coupling, damage to the cylinder piston or to the guiding element, etc.) which arise when the advancing assembly during the successive advancement of the partial assemblies, must overcome abrupt variations in the level of the floor of the mine (such as, for example, trenches and undulations or the like caused by the mining machine).

Normally the coupling should be, within limits, resilient and/or, within limtis, pivotal in the manner of a joint. In the latter case the joint which can be suitably adjusted with respect to its height, is preferably provided at an upper region of the ring or frame-like body.

DETAILED DESCRIPTION OF THE DRAWINGS The invention will now be considered in more detail with particular reference to the drawings.

FIGURES l, 2 AND 3 A three-leg trestle is illustrated and can be seen particularly from FIGURES 1 and 2. The two laterally spaced props are indicated at 52 in FIGURE 1 and 52a and 52b in FIGURE 2 and they are provided in the rear of the device with respect to the conveying means, and the forward prop 49, standing alone, is constructed as a coaxial support including inner and

outer prop units

15 and 10 respectively. A transport path 50 is formed between the forward prop 49 and the rear props 52. The coaxial support 49 has a yoke 25 on its outer prop unit 10 and rounded heads 42 in FIGURE 1 and 42a and 42b in FIGURE 2 are disposed on the yoke and support one forward end respectively of longitudinal caps 46, shown in FIGURE 1, and 46a and 46b in FIGURE 2. These caps are connected to form a frame 45 and the connection is accomplished by means of downwardly cranked

traverse members

43 and 44, which are connected between the longitudinal caps. The longitudinal caps are supported by the

props

49, 52a and 52b, which are mounted 'on a common bottom structure 51 which is rectangular in configuration despite the fact that the props are arranged in triangular fashion. The bottom structure is in the form of a housing and assures stability of the assembly in conjunction with the coaxial support 49. A detachable portion 54 of the bottom structure makes it possible to exchange the support 49. This rectangular form of the bottom structure is of particular advantage as the bottom support of the stronger and forwardly placed prop, and furthermore offers the advantage of providing chambers on both sides rather than beneath the prop for housing guiding elements, direction control devices etc.

In this embodiment the inner prop unit 15 carries a longitudinally extending girder 14. Coupling bodies 108 are provided on both ends of the frame 45, and thus on the

longitudinal caps

46a and 46b, and these are used for carrying forepoling element 111 or pairs of such forepoling elements. These forepoling elements can be hydraulically pressed against the roof and lowered away from the roof and they are preferably provided with tiltable pressure transfer means or load bearing plates 47. Each of these coupling bodies is constructed as a fork member 110, and the forepoling elements are connected thereto by coupling lbolts 112 and are actuated by transverse wedge assembly 13. Such assembly is itself actuated by means of a cylinder piston unit 114 to which it is connected. The arrangement provides the possibility of utilising pairs of forepoling elements on both ends of the trestle and this is due solely to the fact that the upper structural frame is also of rectangular configuration despite the fact that the prop arrangement is triangular.

In order to provide for advancement of the trestle by means of the same advancing device when the trestle is used in its normal position or in another position which it is reversed end-to-end with respect to the normal position, two possibilities are provided by the present invention. One possibility is that a stationary abutment can be provided on the side of the trestle which faces the mine filling. When the trestle is in its reversed position this abutment would be engaged by the advancing device which would have been detached from the mining machine to which it would be connected in the normal position of the trestle, and which now faces the mine filling. The assembly of advancing device and trestle reacts against this abutment during advancement of the trestle. In the normal position of the trestle, as illustrated, the advancing device drags the trestle with it by virtue of its connection to the mining machine. Such an abutment at the gob or filling side of the mine working can be, for example, as indicated in dot-dash lines in FIGURE 3, a pivotable or telescopable transversely extending member 105 which is suitably mounted on a neighbouring trestle. The abutment could also 'be provided by the face of the filling or gobbing itself. The second possibility, which is indicated in FIGURE 4, is to change the position of the advancing device 72 in the trestle from the normal position shown in full lines to a position in which it can 0perate at the opposite end of the assembly as shown in dot-and-dash lines.

In the embodiment of the support assembly illustrated in FIGURES 1 and 2, the longitudinal frame 14 of the inner prop unit 15 is constructed as a narrow frame and comprises two longitudinal caps 14a and 14b which are connected with each other by two socket bearings 41 which form two transverse struts. In accordance with one sequence of upward movement of the support upper structure, the longitudinal inner frame 14 is the first one to be raised to the roof. These socket bearings 41 make it possible to longitudinally displace the girder frame 14 selectively in a longitudinal direction on the prop inner unit and by this means effect a change in length of its lever arms. Pressure transfer means in the form of a pressure plate 40 which is connected to be universally mounted thereto is connected on the shorter and forwardly positioned lever arm of the frame. This universal mounting means that relative rotative movement in all directions, within limits, can take place. This pressure plate 40 transfers a predominant portion of the supporting effect of the inner prop unit into the winning area of the mine or working face of the mine and at the same time creates a zone 106 (see FIGURE 1) at the girder frame 14 and which has no contact with the roof. If desired, tiltable plates 47 can be provided in the forward region of the

longitudinal caps

46a and 46b of the frame 45 and this forward region is supported on the outer prop unit 10.

It should be noted that although in FIGURES 1 and 3 the frame 45 appears to be spaced some distance from the roof of the mine, this has been over-emphasized for purposes of clarity and the outer frame 45 in practice is only spaced a few centimeters from the roof.

FIGURE 3 shows in dot-dash lines the

longitudinal caps

46a, 46b of the outer frame 45 after it is raised to the roof and placed under setting load. The inner prop unit 15 is at first brought to its normal setting load and is then pressed against the roof by means of the raised piston 12 of the outer prop unit until the normal load of the inner prop unit has been reached. If this normal load of the inner prop unit amounts, for example, to 30,000 kp., then 18,000 kp. are eflective upon the roof via pressure plate 40 and inner frame 14 and this latter pressure is in the region of the working area of the mine. If the girder is extended by using section 107, then approximately 21,000 kp. :become eflective upon the roof via the pressure plate 40.

The

props

52a and 52b which carry the rear portion of the frame must also be raised approximately parallel with the raising of the outer prop unit 10 which carries the forward portion of the frame 45. These props 52 must be placed under their setting force at the time that the setting force is applied to the frame 45 by means of the forward prop. This is the A-sequence for placing the coaxial support and its associated members of the upper structure under setting load. In a similar manner the B-sequence can be carried out in which first the outer prop unit 10 is set, and only after termination of this, the

inner prop unit 15 is set to its normal setting load. The two

single props

52a, 52b, due to their relatively large piston area, already have a suitable range for the use of this means at a pressure in the pressure medium supply of, for example, only 100 kp./cm. Then it is also possible to' subject the two

single props

52a, 52b, to pressure in continuous adjustment to the respective pressure medium supply to the two

props

10, 15 of the coaxial support.

After termination of each advancing step of the support assembly, there is only a single manipulation which is required to again raise the inner prop unit 15 and its longitudinal frame to provide immediately an initial effective support for the free face area of the mine along its entire extension, that is, as shown in FIGURE 1, practically from the working face of the mine to the rear end of the assembly. When this is done, the operator, who can then be at ease since the mine is supported, can take his time to set the urther suporting elements into operation in a sequence which he deems correct for extending conditions.

FIGURES 4 AND 5 FIGURE 3 is a sectional view through the bottom structure 51. This bottom structure is also rectangular and forms part of a three-leg support trestle. The trestle can be advanced along a path extending longitudinally of the trestle by an advancing device. The direction of advancement relative to a medial, longitudinally extending, reference axis is determined by a direction control device disposed in the bottom structure, and such direction control device is a special feature of the present invention. A transverse yoke 70 is provided which can be connected with the conveying device or mining machine via the eye 73. This yoke 70 is rigidly connected at a right angle with the guide rod 71. Guide rod 71 is mounted to be pivotable in both lateral directions about a fulcrum defined by projections 77 and the guide rod is located in a channel 76 of bottom structure 51, which channel affords lateral clearance with respect to the guide rod.

A piston cylinder unit 72 engages the yoke 70 at 75 in order to effect forward projection of the guide rod 71 and yoke 70 which is connected with the conveying means at 73. The conveyor is first advanced by the forward projection of the guide rod 71 and yoke 70 and subsequently the trestle is dragged up to the new advanced conveyor along a path determined by guide rod 71.

The direction control device provided allows for variations to be effected in the direction of advancement of the trestle since these variations may become necessary under certain circumstances. This direction control device includes a longitudinal cam link which is actuated by piston cylinder unit 78 and has an oblique slot in which is engaged a pin 74 of a transversely movable link 79. These elements of the device which are disposed in the bottom structure 51 are also shown in FIGURE 5 from which it can be seen that the transverse link 79 engages the guide rod 71 by means of a frame body 81 which provides free play for the rod in the upward and downward direction.

In the drawing, the direction control device is illustrated in full lines in its neutral position which means that movement of the trestle will be in a direction parallel to the longitudinal reference axis. If the trestle should assume an angle oblique to the reference axis, for example as may occur because of sliding on a floor which is too steeply inclined, then during the advancing step it is required to be returned to a direction of advancement parallel to the reference axis. This is accomplished by first decoupling the yoke from the conveyor before the trestle is dragged up to the conveyor after advancement thereof and while the trestle is still stationary. Then the guiding rod 71, yoke 70, and the connecting eye 73 are collectively pivoted by means of the

direction control device

78, 80, 74, 79, 81, such pivoting taking place about the projections 77 in the channel 76 and being accomplished by actuating the piston cylinder unit 78. If the cylinder 78 is moved in the direction of arrow D when the guiding rod 71 and yoke 70 are moved in the lateral direction indicated by arrow C. The projection of guide rod 71 and yoke 70 into the position indicated in dot-dash lines is then effected, and subsequently the eye 73 is connected to the conveyor or mining machine and then the trestle can be turned. For this purpose the upper structure is first lowered and the trestle then turned into the new direction by actuating the piston cylinder unit 78 in the rearward direction. Finally, the trestle is again moved forward to the conveyor or mining machine by corresponding actuation of the piston cylinder unit 72.

A two-support assembly can be formed by supplementing the three-leg trestle shown in FIGURE 4 by placing a partial assembly in front of it. Such partial assembly would preferably be provided with only one prop or a coaxial assembly of inner and outer prop units. The transverse yoke 70 of the guide rod 71 would then be connected with the forward partial assembly 55 as indicated in dot-dash lines in FIGURE 4. This can be accomplished, for example, in a manner similar to the embodiment hereinafter described with reference to and shown in FIGURE 9. Then the two partial assemblies can be advanced in separate alternate steps as usual.

Also indicated in FIGURE 4 in dot-dash lines is an example of modification possibilities provided with the present invention for the guiding

assembly

70, 71, 73 and the advancing cylinder 72. In order to render it possible to advance the three-leg trestle as an individual assembly, in the opposite direction from that discussed above, which is necessary, for exam le, when the assembly is used during mining with artificial gobbing where the trestle has its coaxial support facing the gobbing. In this case the mining machine is positioned forwardly of the trestle end formed by the two

single props

52a and 52b and the advancing device is mounted at its new modified position indicated in dot-dash lines and may be connected again with the mining machine.

FIGURES 6, 7, 8 AND 9 In the embodiment illustrated in FIGURES 6, 7, 8 and 9 an arrangement is shown which provides the possibility of breaking down or disassembling the coaxial support and using its components to form two single props placed one behind the other. This is accomplished by removing the inner unit 15 from the outer prop unit 10 and placing it upon its own bottom plate 116. Thus, a partial assembly 115 is formed which is shown in the drawing as being directed towards the working area of the face and being independently movable. The outer prop unit 10 remains in the bottom structure 51 of the remainder of the assembly which is also reduced to a partial assembly 124. This prop is connected with the partial assembly 124 only by the hydraulic advancing device 72 which is effective upon the guiding

element

133, 71 connected to the frame body 120, and this frame body 120 comprises the partial assembly 115.

In order to place the prop 15 in a systematically controlled manner on a selectively higher setting load than that which it usually has, as was possible with the earlier described arrangement, it is inserted into a pot-like piston cylinder unit 119 which partially employs the principle of the outer prop unit 10. This piston cylinder unit now forms only a setting load amplifier having a short stroke and having its pressure medium supply controlled by means of a permanently provided pressure control means such as a stationary pressure gauge. The hollow piston 118 of this unit is short as shown in the figure but can also be made of a greater length and the outer cylinder 117 of this unit which encompasses the prop 15 with a relatively large clearance holds the prop 15 with elastic holding rings (not shown) provided therebetween. The piston stroke of the setting load amplifier can be limited by a stop or also by an outlet or discharge nozzle which may be opened by the piston when the height of the desired stroke is exceeded.

The setting load amplifier is connected with the bottom plate 116 and in the event the outer cylinder of the setting load amplifier is raised, by a large extent, as shown in the figure, and in the case of longer props this would be to a correspondingly larger extent, then it forms in its second function the base for the prop carried by the hollow piston. If it were solely to function as a setting load amplifier, the cylinder could be of a substantially lower construction.

When conditions required continuous use of the coaxial support in its taken-apart or disassembled state of the two single props, as shown in FIGURE 6, it is then possible to replace the relatively voluminous outer prop unit 10 with a weaker prop such as a prop which is weaker by approximately 25-30% which then carries the yoke 25 after having been adapted to serve this purpose.

A device which slows down the build-up of pressure is required in certain cases for controlling the pressure buildup in the prop in such a manner that the operator can control the prop setting load to a fine adjustment. In FIGURE 6, this function is accomplished by the elasticity of that portion of cap 14 supported by prop 15 which is maintained out of contact With the roof region 106 due to the effect of the plate 40. Since the degree of bending is visible, the operator can control the pressure build-up in the cylinder in case the stationary pressure gauge fails to operate or in the event that no such pressure gauge is provided. Therefore, the operator can to a sufiieiently safe degree and at least with a rough adjustment, differentiate the setting load of the prop and/or the effect of the setting load amplifier.

In order to make the amount of elastic bending of the cap even more clearly visible and particularly to make it larger optically, a relatively long rod may be provided in a simple manner as can be seen in FIGURE 1. This rod extends along the longitudinal direction of cap 14 at a distance from the cap and is fastened at one end to a lateral pivot pin 171 provided in the region of the point of intersetcion of the prop axis and the cap axis. The rod thus acts as a pointer and at its free end points to a graduation 172 provided at the cap and this graduation is a scale or the like.

This indicator device which is provided at the upper portion of the support can be replaced when a setting load amplifier such as is shown in FIGURE 6 is used by a marking 172 and provided at the outer prop of the hydraulic prop which coacts with a pointer 170a mounted on the upper edge of the cylinder 117 of the load amplifier.

It is also possible to simplify this arrangement, i.e. to

dispense with said pointer if the scale is arranged deeper on the outer prop of the hydraulic prop so that it becomes more or less visible when the piston of the setting load amplifier is telescoped upwardly corresponding to the degree of bending of the cap.

Since the values indicated can be very small, normally it is well to transpose these values to a larger scale by suitable means. For this purpose a pulley 173 is mounted on the outer prop of the hydraulic prop at a higher level that in the case of the first described arrangement, over which pulley a cord 174 runs, one end of said cord being fixed on the upper edge of the cylinder of the amplifier,

the other end bearing a weight on which a pointer 17% is fixed, said pointer co-operating with a scale 172b fixed also on the cylinder. This arrangement results, as needs not to be explained, in the doubling of the values indicated.

The pressure transfer plate 40 cannot be used under certain circumstances, for example when the lowermost layer of the roof is too soft. When this occurs, any other retarding element can be used in place of the girder 14 which in that case is non-resilient. For example, a spring assembly 36 may be provided in the coaxial support suitably arranged at the head of the prop. In this arrangement too there is the possibility of providing an optical indicator of the above-mentioned type to observe the pressure build-up 9 in the cylinder and/or the setting load build-up of the rop.

P Thus, a device has been described which is a combination of resiliently bending elements for delaying or retarding the pressure build-up in the pressure chamber of the prop using any desired optical indicator to indicate the degree of bending. The element effecting the slowing down of the pressure build-up also takes over the function of the otherwise necessary and separate pressure indicator.

A setting load amplifier having a substantially larger diameter in comparison to the diameter of the respective prop carried by the amplifier renders it possible to achieve a pressure amplification up to the normal load of a prop even, in the event a medium pressure is chosen which lies not insubstantially below the usual medium pressure, for example, which lies already at a pressure of about 50 kp./cm. Thus, such a setting load amplifier provides the largest range possible within which the operator can use the prop with differentiated setting load. FIGURES 7 and 8 illustrate a special embodiment of the holding frame 120 which surrounds the lower portion of the partial assembly 115. This holding frame 120 form the connecting member of this partial assembly to connect it with the advancing device or the guiding element of the advancing device. This frame is open upwardly and downwardly and within a limited range permits relative vertical movements and oblique positions of the partial assembly 115 which it surrounds. Lateral slots 122 are provided in the frame and holding pins 121 of the outer cylinder 117 are disposed in the slots and thereby secure theposition of the guiding rods against undesired lateral pivoting during the advancing step. FIGURES 7, 8 and 9 show an embodiment for advancing and; simultaneously controlling the direction of advancement of, or straightening, the assembly and this embodiment is modified with respect to the somewhat similar structure described in connections with FIG URES 4 and 5. This advancing and direction controlling device essentially comprises a U-shaped body 131 which is pivotally mounted about a fixed point in the bottom structure 51, this point being the pivot pin 130. The legs 132 of body;131 are hollow and are chamber-like guides for two guide rods 71 which are cross-connected by the yoke 133. At the ends 134 of the transverse yoke 133 which carries frame 120, the pistons of the two cylinder piston units 72 are connected. When the guide rods 71 are pushedforward by placing the cylinders'72 under pressure, then the guide rods are guided in parallel to the longitudinal reference axis of the rear assembly and in a manner which is not influenced by the cylinders 72. This occurs until their ends 135 enter into the divergent portions 137 of chambers 136. Chambers 136 are stationary and forwardly of the portions 132 atford lateral clearance with respect to the guide rods and thereby permit a limited pivoting of the guide rods 71, yoke 133 and U-shaped body 131. Lateral pivoting of the guide rods 71 about the point of rotation 130 of the U-shaped body 131 and therefore, a change in direction of the advancing assembly is possible within the limits shown in FIGURE 9 in dot-dash lines. This pivoting depends upon whether one or the other of the cylinders 72 is placed under pressure.

The portions 137 of the chambers 136 provide independent rectification of the advancing assembly 124 at the end of its advancing step to its parallel position with respect to the reference axis by co-operation of the rods 71 with the laterally constructed rear ends of the portions 137. The divergent portions 137 can also be placed close to respective ends of the chambers 132 of the U-shaped body 131, and these chambers then assume the guiding function for the guiding element in this'embodiment.

A stop device such as the bolt which may be inserted at 140 makes it possible to set or arrest the direction control device in a predetermined direction and/or makes possible a limitation of its effectiveness to a degree of pivoting determined by the play remaining in the sliding chambers 132. If desired, and particularly if the required pivoting motions are small, it is possible to forego the provision of making the sliding chambers pivotable.

When there are difiicult or troublesome characteristics of the floor of the mine and particularly if it is inclined or dipping to a large degree, then a separate piston cylinder unit 138 may be provided for effecting the above described pivoting operation and which can act independently if desired. This piston cylinder unit 138 is effective upon both ends 139 of chambers 132 or only upon one of the ends, either directly or by means of a rod system 141. In place of this unit it is also possible to use a mechanical device, for example a spindle or the like. In order for it to be effective the support holding the guiding

elements

71, 133 must be stable against rotation about its axis.

A direction control device of the type described above can be used in any desired embodiment of a twosection assembly with, of course, a construction which is adapted thereto, and in such an event it can be advanced in two separate steps with the same advantages. However, it can also be used in connection with one-piece assemblies such as the one shown in FIGURE 1.

FIGURE 7 shows an example of how pivoting of the longitudinal inner girder frame 14 of the upper structure of the assembly can be carried out. This pivoting is to be substantially simultaneous with the pivoting motions of the described new guiding element. As shown in dot-dash lines, a guiding trough 131a is provided for this purpose the the frame-like

upper structure

46a, 46b of the partial assembly 124. The lateral edges 150 of the guiding trough engage a girder 14. This girder has lateral clearance with respect to the

caps

46a, 46b with which it is interleaved. It is supported at 151 and may be pivotally mounted in a manner which is similar to the embodiment shown in FIGURE 8 in which the pivoting body is pivoted about the pin 130, by means of a pin a which for this purpose extends substantially coaxially of pin 130 in a recess provided at the transverse strut 44 of the upper structure. Alternatively another similar pivotal mounting could be provided. In many cases it is sufficient in a support assembly in accordance with FIGURES 6, 7, 8 and 9 to provide wall projections which extend toward one another similar to the projections 77 in the guide chambers 76 of FIGURE 4. These can form pivot bearings for the lower guiding element as well as for the upper l ngitudinal inner girder 14.

In the embodiment shown in FIGURES 6 and 7, it is further advantageous to provide the rear end of the upper structure frame 45 with a pressure plate 47 which is tiltable and is shown in FIGURE 2, or with a pressure plate 48 which is shown in FIGURES 6 and 7, and which is mounted fixedly or detachably. As in the embodiment of FIGURES 1 and 2', wedge gear mechanism 113 actuated by cylinder piston units 114 are provided for pivoting the advancing caps 111 upwardly and downwardly.

What is claimed is:

1. In a mine roof support comprising a bottom structure, a plurality of upwardly extending props carried thereon, an upper structure carried by the props, and traction means for advancing the support, the improvement wherein (a) the upper structure comprises a first part and a second part interleaved laterally with each other and having relative lateral clearance,

(b) means mounting the second part for movement longitudinally of the support in a forward direction relatively to the first part by said traction means,

(c) guide means are provided at the level of said upper structure defining the lateral position and path of advancement of said second part of the upper structure relatively to a reference axis extending medially and longitudinally of the support,

((1) means are provided for adjusting said guide means to vary the angular relationship in a plane parallel to the roof between said path and said reference axis.

2. The improvement according to claim 1 wherein (a) said first part of said upper structure defines a channel open at its forward end for receiving said second part of said upper structure,

(b) the guide means comprises a guide element mounted for positional adjustment in said channel and defining a guide path therealong for said second part of said-upper structure.

3. The improvement according to claim 2 wherein said guide element is positionally adjustable by a hydraulic ram operatively connected therewith.

4. In a mine roof support comprising a bottom structure, a plurality of props carried thereon, an upper structure carried by the props for supporting the roof, and traction means for advancing the support, the improvement wherein (a) the bottom structure includes a first part and a second part and means mounting the second part for movement relatively in a direction longtiudinally and forwardly of said first part, said second part being free from any of said props,

(b) the support includes guide means for determining the direction of movement of said second part relatively to a horizontal, longitudinally extending, reference axis of the support, such guide means having co-operating surfaces disposed respectively on said second part and on said first part of the bottom structure and having the capability of defining paths parallel to said reference axis, and diverging respectively to the left and to the right with respect to said reference axis,

(c) said traction means is operable to move said second part selectively along a path parallel to the reference axis or along one or the other of said divergent paths.

5. The improvement claimed in claim 4 further comprising (a) steering means including a pressure fluid ram arranged with its axis disposed longitudinally of said bottom structure,

(b) mechanism for operatively connecting said steering means with said guide means to provide angular adjustment of the co-operative guide surfaces thereof, said mechanism having input and output members moving respectively longitudinally and transversely of the bottom structure and connected operatively with said ram and with said guide means respectively.

6. The improvement according to claim 5 wherein said mechanism comprises (a) longitudinally movable and transversely movable slide elements,

(b) one bf said slide elements having a guide formation extending obliquely with respect to the longitudinaland transverse path of movement of said slide elements respectively,

(c) the other of said slide elements having a part co-operating with said guide formation to effect transverse movement of said transversely movable slide element in response to longitudinal movement of said longitudinally movable slide element.

7. In a mine roof support comprising a bottom structure, a plurality of props carried thereon, and an upper structure carried by the props for supporting the roof, the improvement wherein (a) said bottom structure includes at least one longitudinally extending, forwardly movable, guide rod,

('b) said bottom structure further includes a part defining a guideway extending longitudinally of said support and in which said guide rod is received and which over at least a portion of its length has a width greater than the corresponding lateral dimension of said guide rod to provide freedom for limited angular movement of said guide rod in said guideway in a plane parallel to the floor,

(0) means for angularly setting said guide rod in said plane in a predetermined angular relation to a longitudinally extending reference axis within the limits of angular movement afforded by said guideway,

(d) power-operated traction means for effecting relative movement between said guide rod and said part of said bottom structure longitudinally of said support to eifect advancement of said part along a direction determined by said angular relation of said guide rod to said reference axis.

'8. The improvement according to claim 7 wherein said means for angularly setting said guide rod and said traction means comprises two piston and cylinder units connected between said forwardly movable part and the remaining part of said bottom structure and energisable selectively to efiect both relative advancement between said guide rod and said part and relative angular move ment therebetween whereby advancement is effected either along a path parallel to said reference axis, or along a path diverging to the left or to the right of said reference axis respectively.

9. The improvement according to claim 8 wherein said guide rod and said part of said bottom structure include respective centering means co-operative with each other in at least one position of said guide rod longitudinally of its advancement path relatively to said part of said bottom structure to align said guide rod substantially parallel with said reference axis.

10. The improvement according to claim 7 wherein (a) said part of said bottom structure includes a body pivotally mounted with respect to the remainder of said part for angular movement in a plane parallel to the floor of the mine,

(b) said pivotal body includes a portion slidably embracing said guide rod with a lateral clearance relatively to said guide rod less than that afforded between said guide rod and the remainder of said guideway.

11. The improvement according to claim 10 wherein said means for angularly setting said guide rod comprises (a) a piston and cylinder unit,

(b) means connecting said unit operatively between said pivotal body and said remaining part of said bottom structure to provide for angular movement of said pivotal body and hence said guide rod in opposite directions with respect to said reference axis.

12. The improvement according to claim 10 wherein (a) said upper structure comprises a first part and :1 second part interleaved laterally with each other and having relative lateral clearance,

(b) a guide element is mounted for positional adjustment at the level of said upper structure to define a guide path for the forward part of said upper struc ture,

(c) upwardly extending connecting means are provided to connect said pivotal body of said bottom structure with said guide element of said upper structure to coordinate the angular position of said guide element with that of said pivotal body and thereby provide for movement of said guide rod of said bottom structure and said second part of said upper structure along at least approximately parallel paths.

13. The improvement according to claim 7 wherein (a) the bottom structure is constructed as a rectangular housing,

(b) the props carried by said bottom structure are three in number, one standing alone adjacent to one end of said bottom structure and the other two standing at respective laterally spaced positions adjacent the opposite end of said bottom structure,

(0) said rectangular housing has longitudinally extending chambers at opposite sides of said one prop,

(d) said guide rod, guideway, and said power-operated means are disposed in said chambers.

14. The improvement according to claim 13 wherein (a) said upper structure is constructed in the form of a rectangular frame,

(b) said one prop is disposed medially of said bottom structure,

(0) one end of said frame is supported from said one prop through the intermediary of a yoke-like member extending laterally therefrom beneath laterally spaced side members of said frame,

((1) the other end of said frame is supported by said laterally spaced props.

.15. The improvement according to claim 13 wherein said one prop is substantially stronger than each of said laterally spaced props.

16. The improvement according to claim 15 wherein said one proper is two to three times as strong as each of said laterally spaced props.

17. The improvement according to claim 7 wherein (a) said part of said bottom structure is constructed as a rear base element,

(b) said guide rod is incorporated in a second part of said bottom structure movable forwardly relatively to the first said part, said second part being constructed as a forward base element,

(c) at least one of said props is disposed on said forward base element and the remainder of said props on said rear base element,

(d) said forward base element includes an annular frame-like body encompassing a lower portion of said one prop and means connecting said one pro with said body with freedom for said prop to move relatively to said body at least in an upward and downward direction.

18. The improvement according to claim 17 wherein said means connecting said body with one prop also 15 affords freedom for said prop to tilt relatively to said body to a limited extent.

References Cited UNITED STATES PATENTS 3,159,003 12/1964 Kearsley 6145 JACOB SHAPIRO, Primary Examiner