US3172340A - Hydraulically operable mine prop - Google Patents

Hydraulically operable mine prop Download PDF

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Publication number
US3172340A
US3172340A US243199A US24319962A US3172340A US 3172340 A US3172340 A US 3172340A US 243199 A US243199 A US 243199A US 24319962 A US24319962 A US 24319962A US 3172340 A US3172340 A US 3172340A
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Prior art keywords
prop
piston
internal
external
prop member
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US243199A
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English (en)
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Blenkle Erwin Heinz
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Bochumer Eisenhuette Heintzmann GmbH and Co KG
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Bochumer Eisenhuette Heintzmann GmbH and Co KG
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/14—Telescopic props
    • E21D15/44—Hydraulic, pneumatic, or hydraulic-pneumatic props
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T403/00—Joints and connections
    • Y10T403/32—Articulated members
    • Y10T403/32606—Pivoted
    • Y10T403/32631—Universal ball and socket

Definitions

  • an external prop member serves as a pressure chamber and is longitudinally shi-ftably guided on an internal prop member closed at its inner end by a piston, said piston engaging the inner Wall of the external prop member in sealing relationship.
  • the internal prop member is rigidly connected to the piston.
  • the conventional mine props of this type have the drawback that, in order to ensure a reliable seal between the external prop member and the internal prop member and to permit an easy slipping of the prop members into and out of each other, six different surfaces of the prop members, partly of considerable dimensions, have to be machined with particular care, and at three places of the mine props the interconnected and telescopic-ally movable prop members must be accurately centered. That is to say, firstly, the piston of the internal prop member must be centered with respect to the inner wall of the external prop member serving as a pressure chamber, and this requires a careful machining of the surfaces of the prop piston and of the inner wall of the external prop member moving on each other.
  • the outer wall of the internal prop member must be centered with respect to a guide cap provided at the lower end of the external prop member, and this again requires an accurate machining of the surfaces thereof moving on each other.
  • these known types of props necessitate a careful centering of the prop piston with respect to the inner end of the internal prop member. This means that two further surface portion-s have to be carefully machined. This treble centering inevitable in the conventional hydraulically operated mine props can only be obtained with the necessary accuracy if precision steel tubes are used which are machine-cut to an accuracy degree of about 5 to p. and thus are considerably more expensive than commercial tubes without such a fine machining.
  • the relative canting between the external and internal prop members must be apprehended primarily in cases where the prop has to take up-as it is frequently the case in underground mining-not only axial forces, but is also exposed to stresses acting more or less transversely to the longitudinal axis of the mine prop. This is, for example, the case when the prop is employed in a medium steep-angle or steep-angle position and/ or serves as an abutment or supporting means for a conveyor or other mining implement.
  • a hydraulically operable mine prop which comprises as external prop member closed at one end, an internal prop member projecting into the external prop member, a prop piston supported on the inner end of the internal prop member and sealingly engaging the inner surface of the external prop member arranged to be longitudinally shiftable on said prop piston and said internal prop member, a plurality of large sliding surfaces provided between said inner end of said internal prop member and said prop piston for connecting said inner end of said internal prop member to said prop piston both in a universal joint fashion and in a laterally displaceable manner to a limited extent, said sliding surfaces contacting each other and said inner end of said internal prop member and said prop piston over an area of substantially constant size irrespective of the inclined position said internal prop member may assume with respect to said prop piston.
  • the internal prop member can be canted with respect to the external prop member as well as laterally displaced to a limited extent, without this relative movement of the internal prop member with respect to the external prop member affecting in any way the position of the prop piston.
  • This important feature affords the advantage that even in cases where the mine prop is subjected to considerable stresses caused by eccentrically acting forces or by forces acting more or less transversely to the longitudinal axis of the prop, the seal between the prop piston and the inner wall of the external prop member is in no way impaired because a canting of the prop piston cannot be effected by such forces.
  • the entire periphery of the prop piston always uniformly sealingly engages the inner surface of the external prop member whereby also irregularities, for example a certain roughness of the inner surface of the external prop member, can be balanced without impairing the seal between the piston and the external prop member. Even if severe mechanical stresses as are inevitable in the rough mining practice have caused a slight permanent deformation of the external prop member, the seal between the external prop member and the piston is practically not affected owing to the connection of the internal prop member to the prop piston as proposed by this invention.
  • Another advantageous feature afforded by connecting the internal prop member to the prop piston both in a universal joint fashion and in a laterally displaceable manner consists in that even in the case of eccentrically acting forces or forces acting more or less transversely to the longitudinal axis of the prop, the inner prop member will assume a relatively slightly inclined position so that the buckling strength is substantially improved.
  • these two parts contact each other with permanently equal-sized contact surfaces so that even with a load of, for example 40 to 50 tons, the bearing pressures occurring between the contact surfaces can be kept so small that any permanent deformation of or damage to the contact surfaces is safely prevented.
  • the inner prop member can easily be made of such a commercial tube without any surface machining, whereas the tube used for the external prop member requires but a simple machining of the inner wall in order to ensure a substantially equal inside diameter over the entire length of the tube as well as a fairly smooth surface.
  • To finish smooth the inner wall of the tube for the external prop member use may be made, for example, of a mandrel and subsequently, if required, of a plurality of rollers rolling on the inner wall of the external prop tube. A further, particularly cutting machining of the surface of the tube used for the manufacture of the external prop member is not required.
  • a further advantageous feature of the invention consists in that for the above-mentioned reasons a much less severe standard needs to be applied to the straightness of the tubes used for the manufacture of the internal and external prop members than to that of the tubes of hydraulically operated mine props of conventional type having a rigid connection between the piston and the internal prop member.
  • the mine prop as proposed by the invention it is possible to accept at a tube length of l m. a lateral deviation of, for example, 2 mm. what is within the range of admissible tolerances of commercial tubes, whereas in the past the straightness of the tubes used for hydraulically operated mine props had to meet rather severe requirements, so that these tubes had to be regularly subjected to a refinishing treatment to ensure the maximum possible straightness thereof.
  • the mine prop as proposed by the invention further contemplates, in contrast to the aforedescribed type of construction, that tubes having a relatively low ratio of slenderness and a sufiicient buckling strength may also be used for the internal prop member.
  • a guide is provided at the lower end of the external prop member to guide the same on the inner prop member, which guide can be of much simpler construction and can have a correspondingly ampler tolerance.
  • the inner end of the internal prop member has a convex configuration and rests on a ball of a relatively small diameter which is mounted in the prop piston so that as a consequence of the very small area of contact between the internal prop member and the piston extremely high bearing pressures will occur which lead within a minimum of time to a permanent deformation of the contact surfaces.
  • This deformation practically eliminates the lateral displaceability of the internal prop member with respect to the prop piston, which displaceability, moreover, is deliberately kept low by the lateral guide means.
  • the lateral displacea'oility of the internal prop member with respect to the prop piston is limited by the lateral telescopically extensible guide means to a small extent lying Within the manufacturing tolerances of these guide means, and any inclination of the internal prop member with respect to the external prop member is deliberately precluded by these guide means.
  • an intermediate member is mounted for displacement to all sides to a limited extent transversely to the longitudinal axis of the mine prop and connects the inner end of the internal prop member to the prop piston in universal joint fashion.
  • the intermediate member has an even and a calotte-shaped sliding surface of either convex or concave configuration.
  • the intermediate member may have an even sliding surface which is laterally shiftable to all sides to a limited extent on a sliding surface of the internal prop member or the prop piston which is disposed transversely to the longitudinal axis of the mine prop.
  • the intermediate member may have a calotte-shaped sliding surface which is supported on an inversely calotteshaped sliding surface of the internal prop member, the prop piston or an interposed pressure member.
  • This pressure member conveniently has on either side calotte-shaped sliding surfaces and may be arranged between the prop piston and the intermediate member or between the inner end of the internal prop member and the intermediate member.
  • the mine prop as proposed by the invention further provides that the sliding surfaces are provided on the internal prop member, the intermediate member, the prop piston, and the pressure member, if any, and, in any inclined position the internal prop member may assume engage each other with substantially equal-sized surface portions corresponding to a substantial portion-for example one half-of the piston diameter.
  • the engaging calotte-shaped sliding surfaces of the intermediate member, of the pressure member, if any, and of the prop piston have, as a rule, equal radii of curvature, so that in any inclined position of the internal prop member with respect to the external prop member and the prop piston guided therein, the contact surfaces between the relatively supported parts will remain of equal size. In this case it is possible to make the calotte-shaped and the even sliding surfaces of such a size that they extend across an essential portion of the piston diameter and no permanent deformations of the contact surfaces can occur even if the prop is subjected to particularly severe strains.
  • the pressure member which serves to further improve the connection between the prop piston and the internal prop member in a universal joint fashion and in a laterally displaceable manner may have biconvex or double con- 6 cave sliding surfaces. It is, however, also possible to provide this pressure member with convexo-concave sliding surfaces.
  • Still another feature of the invention consists in that the prop piston and/or the pressure member and/or the intermediate member and/ or the inner end of the internal prop member may be made, entirely or partially, of a synthetic plastic material having a great resistance to compression and a highly smooth surface finish, whereby not only the weight of the prop can be considerably reduced but also the necessity of lubricating the sliding surfaces moving upon each other can be dispensed with.
  • passage means may also be provided between the pressure chamber formed between the piston and the upper closed end of the external prop member and the interior of the internal prop member.
  • substantially the same fluid pressure will be maintained in the pressure chamber and in the interior of the internal prop member, which will act on the upper closed end of the external prop member as well as on the closed bottorn end of the internal prop member, so that outside pressures acting on said opposite ends of the mine prop during use of the same in supporting the roof of the mine shaft, will be at least in part taken up directly by the fluid pressure in the interior of the mine prop so that the external as well as the internal prop member will be subjected mainly to bursting pressure.
  • mine props according to the present invention may be constructed for the same length and the same load capacity as that of the prior art with smaller cross sectional dimensions, which will result in a lighter construction.
  • This feature of the present invention in which the pressure chamber and the interior of the internal prop member are connected to each other by passage means, may be used in a mine prop in which the prop piston and the inner end of the internal prop member are connected to each other for limited universal tilting movement relative to each other about a tilting pointlocated at the axis of the internal prop member and for limited movement relative to each other transverse to said axis, as well as in such arrangements in which the prop piston and the inner end of the internal prop member are connected only for universal tilting movement relative to each other.
  • the passage means have to be constructed in such a manner so as not to prevent the afore- .mentioned movements of prop piston and internal prop member relative to each other.
  • the passage means have also to be constructed in such a manner as to prevent passage of pressure fluid to the exterior of the mine prop.
  • the passage means preferably include a conduit passing through central bores formed in the prop piston or piston means and through wall means closing the inner end of the internal prop member.
  • the conduit has to be constructed from such material to properly withstand the pressure of the pressure fluid, that is the pressure in the order of 400 to 500 atmospheres, and this conduit has to be arranged with respect to the prop piston and the aforementioned wall means in such a manner as to not prevent the movement of the prop piston relative to the Wall means of the internal prop member mentioned above.
  • the conduit is connected to the prop piston and the aforementioned wall means in such a manner to assure, even if the arrangement is not under load, that the prop piston will follow any longitudinal movement of the internal prop member when the latter is drawn out of the external prop member.
  • the conduit means may be made from elastic or flexible material such as rubber or rubber-like plastic and in this case the conduit is preferably armored in known manner to withstand the high pressures it is subjected to.
  • the flexible or elastic high pressure and armored hose is preferably fluid-tightly connected at opposite ends thereof to the prop piston and the wall means which close the inner end of the external prop member.
  • the connection is made in such a. way that it is releasable and in a preferred construction the conduit and the connecting elements are constructed; as a unit and arranged with respect to the other members of the mine prop in such a manner that they can be removed therefrom as a unit when exchange of the conduit means is desired.
  • a flexible and elastic conduit it is also possible to assemble this conduit with other elements of the arrangement with a certain pretension so that the conduit will tend to press prop piston and the wall means which close the inner end of the internal prop member against each other.
  • Another advantageous arrangement is to make the conduit from relatively rigid material, preferably from metal or from relatively rigid plastic material.
  • the rigid conduit has to be arranged and connected to the prop piston and the end wall means at the inner end of the internal prop member in such a manner that the aforementioned relative movement of these members is not impeded, and, of course, the arrangement has to be made in such a manner to prevent undesired escape of pressure fluid from the interior to the exterior of the mine prop. This can be obtained for instance by fluid-tightly connecting the rigid conduit at opposite ends thereof by highly elastic connecting members to the prop piston and to the wall means at the inner end of the internal prop member.
  • the rigid conduit is rigidly connected at one end thereof either to the piston means or to the aforementioned wall means, whereas the other end portion of this conduit extends with ample clearance through a bore in the other of the means.
  • resilient means which press the engaging surfaces of prop piston and the end wall means of the internal prop member against each other to assure a proper seal under all operating conditions that is, also when the mine prop is not under load.
  • Another possibility to form a proper seal in such an arrangement is to provide sealing bellows from elastically deformable material between that end of the rigid conduit which extends with ample clearance through the prop piston or theaforementioned end wall means bridging the gap between the free end of the rigid conduit and that member through which it extends with ample clearance. It is also possible to form the passage means it-. self by bellows from elastic material fluid-tightly connected to the prop piston and the end wall means closing the inner end of the internal prop member.
  • FIG. 1 is a longitudinal section through a hydraulically operated mine prop according to the invention
  • FIGS. 2 to are longitudinal sections through four further forms of construction of the mine prop
  • FIG. 6 is a longitudinal section through a hydraua: lically operated mine prop according to the present invention and showing a modification similar to the construction shown in FIG. 1, but differing therefrom by the provision of passage means connecting the interior of the external and the internal prop members;
  • PEG. 7 is a partial longitudinal section through a different embodiment according to the present invention, likewise showing a passage means connecting the interior of the prop members;
  • FIG. 8 is a partial longitudinal section through a further embodiment of such a construction.
  • an external prop member 1 consisting of a commercial tube is provided at its upper end with a head plate 2 by means of which the upper end of the external prop member 1 is tightly sealed against pressure fluid.
  • a fill-up valve 3 and a relief pressure valve 4 are mounted in the head plate 2, on diametrically opposite sides thereof.
  • the relief pressure valve 4 is provided, in addition, with an operating handle 5 with the aid of which it can be opened already before its minimum pressure of response has been reached, so that the relief pressure valve 4 serves at the same time as a pressure-reducing valve.
  • a prop piston 6 is arranged and sealingly engages the inner surface of the external prop member.
  • the head plate 2, the external prop member 1 and the prop piston 6 define a pressure chamber 8 which is sealed by a packing 7 consisting of synthetic plastic material and provided on the prop piston 6.
  • a packing 7 consisting of synthetic plastic material and provided on the prop piston 6.
  • adjusting ring 9 threaded on to the prop piston 6.
  • the prop piston 6 is provided on the side remote from the pressure chamber 8 with a recess having a sliding surface 11 which is engaged by. the top surface 13 of an intermediate member 12, this top surface likewise being constructed as a sliding surface.
  • the opposite surface 14 of the intermediate member 12 is calotte-shaped and of concave configuration and has a radius of curvature corresponding to that of the likewise calotte-shaped but convex top surface 15 of an end piece 17 mounted on the inner end of an internal prop member 16 on which the external prop member 1 is longitudinally shiftable.
  • the end piece 17 is provided with an outer thread and screwed into an inner thread provided at the inner end of the internal prop member 16 and is supported on the latter with its border Zones forming a shoulder protruding beyond the internal prop member 16 so that the end piece 1'7 can transmit compressive forces to the internal prop member 16 substantially without stressing the thread.
  • a screw bolt 18 passing through the end piece 17 and the intermediate member 12 and threaded into the prop piston 6 serves to connect the prop piston 6 with the inner end of the internal prop member 16 with a limited axial and radial play.
  • the internal prop member 16 has at its lower end a prop base 20 welded thereto.
  • a prop piston 6 has a convex sliding surface 11a facing the internal prop member 16.
  • An intermediate member 1211 having a calotte-shaped concave sliding surface 13a of like radius of curvature engages therewith the sliding surface 11a, whereas, on the side facing the internal prop member 16, it has an even sliding surface 14a which in turn bears against a likewise even sliding surface 15a provided in a recess of an end piece 17a.
  • the internal prop member 16 is detachably coupled to the prop piston 6a by means of the screw bolt 18 with a slight axial and radial play.
  • the screw bolt 18 passes through bores provided in the end piece 17a and the intermediate member 120, the diameter of these bores being greater than the diameter of the screw bolt 18.
  • FIG. 3 shows a pressure member 21 which is disposed between a sliding surface 11b, provided in a recess of a prop piston 6b, and a concave sliding surface 13b provided on an intermediate member 12b.
  • This pressure member 21 has on one side a convex sliding surface and on the other side a concave sliding surface, the radii of curvature of both sliding surfaces being conformed to the .countersurfaces of the prop piston 6b and the intermediate member 12b, respectively.
  • a prop piston 60 has a concave sliding surface 110 facing the internal prop member 16.
  • An intermediate member 120 also has a concave sliding surface 130 facing the prop piston 6c. Between these two sliding surfaces 11c and 130 there is disposed a pressure member 22 having biconvex sliding surfaces.
  • FIG. shows convex sliding surfaces 11d and 13d of a prop piston 6d and an intermediate member 12d, respectively, which bear against double concave sliding surfaces of an interposed pressure member 23.
  • each of the prop pistons 6b, 6c and 6a is detachably coupled to an end piece 17b, 17c and 17d, respectively, of the internal prop member 16 with a limited axial and radial play.
  • the screw bolt 18 is screwed into the prop piston in such a manner that both the end piece and the intermediate member as well as the pressure member, if any, are guided by the screw bolt with a limited radial play.
  • the screw bolt 18 may serve as a pressure fiuid conduit connecting the pressure chamber 8 with the interior of the internal prop member 16 constructed as a reservoir.
  • the screw bolt 18 may, for example, be constructed as. a tube and connect the pressure chamber 8 with the interior of the internal prop member 16, suitable valves being incorporated in the tube.
  • the guide member 19 mounted on the lower end of the external prop member 1 to guide the same on the internal prop member 16 has so ample a tolerance that the internal prop member 16 can be canted by at least about 2 to 3, but preferably more degrees, in relation to the longitudinal axis of the external prop member 1, and this will cause the calotte-shaped sliding surfaces provided between each of the prop pistons 6, 6a, 6b, 6c and 6d and the internal prop member 16 to be displaced relatively to each other.
  • the ample tolenance of the guide member 19 also permits a transverse displacement of the internal prop member 16 parallel to the longitudinal axis of the mine prop.
  • This'liateral displacement is limited by the play of the intermediate member 12 in the recess of the prop piston 6 or of the intermediate members 12a, 12b, 12c and 12d in the recesses of the end pieces 17a, 17b, 17c and 17d.
  • the lateral displaceability of the intermediate members and of the pressure members can be limited by the limitation of the radial play thereof on the screw bolt 18.
  • the lateral displaceability may, for instance, amount to 2 to 3 mm. to all sides and is so chosen that it is in any case greater than the lateral dis- 1f) tance between the end pieces 17, 17a, 17b, or 17d and the inner surface of the external prop member 1.
  • the intermediate members 12, 12a 12b, 12c and 12d and the pressure members 21, 22 and 23 may consist of synthetic plastic materials having a high resistance to compression and a high-grade smooth surface finish. Use may be made particularly of thermoplastic or thermo elastic hard synthetic materials having a low elastic deformability, a high resistance to wear and good anti-friction properties, i.e. a low coeflicient of friction. Typical representatives of this kind of synthetic plastic materials are the hard polyamides. Such hard synthetic plastic materials have a high resistance to compression, a high modulus of elasticity and a high softening or fusing temperature. Principally, all synthetic plastic materials may be used which are employed in the manufacture of bearing bushings and gear wheels.
  • the whole prop piston of a synthetic plastic material having a high resistance to compresison and a high-grade smooth surface finish
  • the packing 7 is made of a synthetic plastic material hava greater capacity for elastic deformation and, nevertheless, good wear properties.
  • the end pieces 17, 17a, 17b, 17c and 17d of the internal prop member 16 may also be made of such a synthetic plastic material having a high resistance to wear and a high-grade smooth surface finish.
  • FIG.6 shows an arrangement similar to that shown in FIG. 1 and differing therefrom only in that the connecting means which connect the prop piston with the inner end of the external prop member include passage means providing communication between the pressure chamber formed in the external prop member above the prop piston and the interior of the internal prop member.
  • the general arrangement of the mine prop shown in FIG. 6 has been described before in connection with FIG. 1 and repetition of this description seems therefore superfluous. It is mentioned that such parts or elements of the arrangement shown in FIG. 6 which are identical with those shown in FIG. 1 have been provided with the same reference numerals whereas such parts which have been slightly modified in the arrangement shown in FIG. 6 have been provided with reference numerals which are the same as used in FIG. 1 to which, however, a prime has has been added.
  • the piston means 6', 12' are universally tiltab'le about a pivot point located at the axis of the internal prop member 16 and also shiftable to a limited extent in a direction transverse to this axis with respect to the end wall means 17' which close the inner end of the internal prop member 16 in the same manner as the arrangement shown in FIG. 1.
  • connecting means shown in FIG. 6, which connect the piston means 6', 12' to the end wall means 17' for simultaneous movement in axial direction with each other include passage means which provide communication between the pressure chamber 8 formed in the external prop member 1 above the piston means and the interior of the internal prop member 16.
  • the passage means are provided by a conduit 40, constructed as an elastic high pressure hose formed from rubber or rubber-like plastic material and preferably armored to withstand the high pressure the arrangement is subjected to, which extend through axially aligned bores 29, 26, 28 respectively formed in the prop piston 6', the intermediate member 12', and the end wall 17 closing the inner end of the internal prop member 16.
  • a conduit 40 constructed as an elastic high pressure hose formed from rubber or rubber-like plastic material and preferably armored to withstand the high pressure the arrangement is subjected to, which extend through axially aligned bores 29, 26, 28 respectively formed in the prop piston 6', the intermediate member 12', and the end wall 17 closing the inner end of the internal prop member 16.
  • the outer diameter of the conduit 40 is considerably smaller than the diameter of the aforementioned bores and the upper end of the conduit 40 is held in the bore of the prop piston 6 by a substantially tubular connecting member 24 provided at its upper end with an external screw thread engaged by a nut member 23, which when tightened will press the radially extending flange at the lower end of the connecting member 24 against a shoulder formed in the stepped bore 29 through the piston 6'.
  • a substantially tubular connecting member 24 provided at its upper end with an external screw thread engaged by a nut member 23, which when tightened will press the radially extending flange at the lower end of the connecting member 24 against a shoulder formed in the stepped bore 29 through the piston 6'.
  • a substantially tubular connecting member 24 provided at its upper end with an external screw thread engaged by a nut member 23, which when tightened will press the radially extending flange at the lower end of the connecting member 24 against a shoulder formed in the stepped bore 29 through the piston 6'.
  • a substantially tubular connecting member 24
  • sealing member 25 is sandwiched between the upper face of the radially extending flange on the member 24 and the shoulder face on the prop piston 6.
  • the lower end of the conduit 40 is connected to the end wall 17 by a substantially tubular connecting member 22 provided at its inner end with an external screw thread screwed into a corresponding internal screw thread formed in the surface of the bore 28 extending axially through the end wall 17'.
  • the conneoting'member 22 is preferably formed at its lower end with a radially outwardly projecting flange having an upper annular surface facing a corresponding annular surface on the end wall 17' and a sealing member 21 is preferably sandwiched 'between these two annular surfaces.
  • conduit 40 The upper and lower ends of the conduit 40 are fluid-tightly connected to the tubular connecting member 24 and 22, respectively, by cementing or by vulcanizing.
  • Conduit 40 and connectingmembers 22 and 24 thus form a single unit and since the diameters of the bores 26, 28 through members 12' and 17' are made to the same size as the maximum diameter of the connecting member 24 this unit may be removed without disassembly from the arrangement by simply unscrewing the nut member 23.
  • FIG. 7 differs from all of the previously described arrangements in that in this modification the prop piston 6" directly engages the end wall 17" which closes the inner end of the internal prop member 16. Piston 6 and end wall 17" engage each other along spherical faces 6a and 15 respectively formed on the prop piston 6 and the end wall 17".
  • These spherical faces are of equal radical curvature which is considerably greater than half the diameter of the piston 6 and these spherical surfaces 112 and :15 extend in a direction transverse to the longitudinal axis of the internal prop member a distance at least half of the diameter of the prop piston 6" so that the prop piston 6" and the end wall 17" abut against each other along relatively very great faces extending substantially transverse to the axis of the prop so that the specific surface pressure on these faces when the prop is used to support the roof of a mine shaft are relatively small, while the prop piston 6" and the end wall 17 on the inner end of the internal prop member 16 may universally tilt with respect to each other to a limited extent.
  • the construction shown in FIG. 7 provides also for communication between the pressure chamber 8 above the prop piston 6" and the interior -27 of the internal prop member 16.
  • the elastic high pressure hose 40' which may be made from the same material as described in connection with the embodiment shown in FIG. 6, is formed in the modification shown in FIG. 7 at opposite ends thereof with radially outwardly extending beads 40a which are respectively fluid-tightly connected to the prop piston 6" and the end wall 17".
  • tubular connecting members 31 and 310 provided at flange por- H tions thereof with outer screw threads and respectively engaging with internal screw threads formed in bores 38 and 30a respectively formed through the prop piston 6" and the end wall 17 so as to press the beads 40a of the conduit or high pressure hose 49 against annular surfaces 32 and 32a formed according to the form of the beads 40a in the prop piston 6" and the end wall 17".
  • annular sealing members 33 and 33a are sandwiched between the beads 48a and the engaging flange portions of the connectingmembers 31 and 31a.
  • the portions 34 and 34a of the bores through the prop piston 6 and the end wall 17", which surrounds the portion of the conduit 40 between the beads thereof are conically enlarged toward the surfaces lle and 15, respectively, to permit universal tilting movement of prop piston 6" relative to end wall '17" and relative shifting of these two members with respect to each other during such tilting movement without impediment of such movement by the conduit 49'.
  • the pro-p piston 6" and the end wall 17" of the internal prop member are thus con- 12 nected for limited universal tilting movement and for simultaneous movement in longitudinal direction, while the pressure chamber 8 and the interior 27 of the internal prop member communicate with each other and while escape of pressure fluid from the pressure chamber 8 or the interior 27 of the internal prop member into the space 37 between the outer surface of the internal prop member and the inner surface of the external prop member 1 is positively prevented, While FIG. 7 shows only a part of the mine prop, it is understood that the external prop member 1 is closed at the upper end as shown in FIGS. 1 and 6 and provided at its lower end with a guide member 19, whereas the lower end of the external prop member is closed by a plate 29 as likewise shown in the aforementioned figures.
  • the modification shown in FIG. 8 is similar to the modification shown in FIG. 7 in that in the modification illustrated in FIG. 8 the prop piston 6" engages with the end wall 17 on the inner end of the internal prop member 16 along spherically curved faces He and 15 which are constructed in the same manner as the corresponding spherical faces described in connection with FIG. 7, but the modification shown in FIG. 8 differs from that shown in FIG. 7 in that the conduit 46" which provides communication between the pressure chamber 8 above the prop piston 6 and the interior 27 of the internal prop member 16 is in the form of a rigid conduit 40 which is preferably made from metal. In order not to impede universal tilting movement of prop piston 6" and end wall 17" relative to each other, the rigid conduit.
  • annular sealing means 38 is preferably formed as an O-ring inserted in an annular groove formed as shown in the prop member 6". Of course it is also possible to arrange the annular sealing means 38 in a groove extending from the spherical surface 15 into the end wall 17".
  • the embodiment shown in FIG. 8 preferably includes also a resilient means for pressing the spherical faces He and 15 against each other and to compress thereby the O-ring 38 in the groove formed in the prop piston 6" or in the end wall 17".
  • the resilient means are in the form of a spring washer 39 which is slightly cupped and which engages with the outer peripheral edge the bottom face of the end wall 17" around the bore 36 therethrough, whereas the inner peripheral edge of the spring washer 39 engages a head 49b formed on the bottom end of the conduit 49" which extends beyond the bore 36.
  • the spring washer 39 is under tension to press thereby the spherical surfaces 11c and 15 against each other, to assure a proper seal and prevention of escape of pressure fluid from the pressure chamber 8 or the interior 27 of the external prop member in the annular space 37 between the outer surface of the internal prop member 16 and the inner surface of the external prop member 1.
  • conduit 40 could be screwed with a lower end thereof into a corresponding threaded bore vformed in the end wall 17", in which case the upper portion of the conduit would have to extend with clearance through an enlarged bore formed in the prop piston 6", whereas the spring washer 39 would be located between the enlarged head 4%, extending in this case upwardly beyond the prop piston 6" and the latter.
  • the prop pistons and the end walls at the inner end 13 of the external prop member in the embodiment shown in the FIGS. 68 may be formed from steel or any appropriate plastic material which combines great mechanical strength with small elastic deformability with resistance against oil, acid and aging. Plastic materials of such characteristics can for instance be found in the plastic materials of the polyamide group.
  • conduit means shown in FIG. 6 may also be used in the general arrangement illustrated in FIGS. 7 and 8 in which the intermediate member 12' shown in FIG. 6 is omitted and which the prop piston and the end wall on the inner end of the internal prop member directly engage each other along spherically curved surfaces.
  • the conduit means as illustrated in FIGS. 7 and 8 may also be used in the general arrangement as shown in FIG. 6.
  • a spring washer as shown in FIG. 8, may be located between the head of the screw 18 and the bottom face of the end wall closing the inner end of the internal prop member.
  • a hydraulic mine prop comprising, in combination, an external tubular prop member having an axis and being closed at one end; an internal prop member having an end portion projecting with clearance into said external prop member and being movable towards and away from said closed end of said external prop member; a prop piston at the inner end of said internal prop member and sealingly engaging the inner surface of said external prop member to form therewith between said piston and said closed end a pressure chamber; connecting means for connecting said piston and said inner end of said internal prop memher for simultaneous movement toward and away from said closed end and for limited universal tilting movement relative to each other; and means for feeding pressure fluid into and out of said pressure chamber.
  • a hydraulic mine prop comprising, in combination, an external tubular prop member having an axis and being closed at one end; an internal tubular prop member closed at opposite ends and having an end portion projecting with clearance into said external prop member and being movable towards and away from said closed end of said external prop member; a prop piston at the inner end of said internal prop member and sealingly engaging the inner surface of said external prop member to form therewith between said piston and said closed end a pressure chamber; connecting means for connecting said piston and said inner end of said internal prop member for simultaneous movement toward and away from said closed end and for limited universal tilting movement relative to each other about a tilting point located at said axis and including passage means for connecting said pressure chamber with the interior of said internal prop member; and means for feeding pressure fluid into and out of said pressure chamber.
  • a hydraulic mine prop comprising, in combination, an external tubular prop member having an axis and being closed at one end; an internal prop member having an end portion projecting with clearance into said external prop member and being movable towards and away from said closed end of said external prop member, said internal prop member including at said end portion end wall means facing said closed end of said external tubular prop member; piston means supported on said end wall means 14 of said internal prop member and sealingly engaging the inner surface of said external prop member to form therewith between said piston means and said closed end of said external prop member a pressure chamber, said end wall means and said piston means engaging each other along spherical surfaces so that said internal prop member may universally tilt to a limited extent with respect to said piston and with respect to said external prop member, said spherical surfaces having equal radii of curvature greater than the radius of the peripheral surface of said piston means and at least one of said spherical surfaces extending in direction transverse to said axis a distance greater than half of the diameter of said piston means; connecting means for connecting said piston means
  • a hydraulic mine prop comprising, in combination, an external tubular prop member having an axis and being closed at one end; an internal prop member having an end portion projecting with clearance into said external prop member and being movable toward and away from said closed end of said external prop member; a prop piston at the inner end of said internal prop member and sealingly engaging the inner surface of said external prop member to form therewith between said piston and said closed end a pressure chamber; connecting means for connecting said piston and said inner end of said internal prop member for simultaneous movement toward and away from said closed end and for universal tilting movement relative to each other about a pivot point located at said axis as well as for limited movement relative to each other transverse to said axis; and means for feeding pressure fluid into and out of said pressure chamber.
  • a hydraulic mine prop comprising, in combination,
  • an external tubular prop member having an axis and being closed at one end; an internal prop member having an end portion projecting with clearance into said external prop member and being movable toward and away from said closed end of said external prop member; a prop piston at the inner end of said internal prop member and sealingly engaging the inner surface of said external prop member to form therewith between said piston and said closed end a pressure chamber; connecting means for connecting said piston and said inner end of said internal prop member for simultaneous movement toward and away from said closed end and for universal tilting movement relative to each other about a pivot point located at said axis as well as for limited movement relative to each other transverse to said axis; guide means at the other end of said external prop member for guiding said other end on the outer surface of said internal prop member, said guide means surrounding said internal prop member with clearance; and means for feeding pressure fluid into and out of said pressure chamber.
  • a hydraulic mine prop comprising, in combination, an external tubular prop element having an axis and being closed at one end; an internal prop member having an end portion projecting with clearance into said external tubular prop element and being movable toward and away from said closed end of the latter; a piston member located adjacent the inner end of said internal prop member and sealingly engaging the inner surface of said internal prop element to form therewith between said piston member and said closed end a pressure chamber; at least one abutment plate sandwiched between said internal prop member and said piston member and having a substantially plane surface extending transverse to said axis and a spherically curved surface extending transverse to said axis and one of said members being formed with a plane surface engaging said plane surface of said abutment plate and the other of said members having a spherically curved surface engaging said spherically curved surface of said abutment plate; means connecting said members and said abutment plate for simultaneous movement toward and away from said closed end while permitting limiting sliding movement of said surfaces relative to each other
  • a hydraulic mine prop comprising, in combination, an external tubular prop element having an axis and being closed at one end; an internal prop member having an end portion projecting with clearance into said external tubular prop element and being movable toward and away from said closed end of the latter; a piston member located adjacent the inner end of said internal prop member and sealingly engaging the inner surface of said external prop element to formtherewith between said piston member and said closed end a pressure chamber, one of said members being formed at a portion thereof facing the other of said members with a cavity having a plane end surface transverse to said axis and a peripheral surface; at least one abutment plate sandwiched between said internal prop member and said piston member and being located in said cavity, said abutment plate having a plane surface engaging said plane end surface of said cavity and having opposite said plane surface a spherically curved surface extending transverse to said axis and the other of said members having a spherically curved surface engaging said spherically curved surface of said abutment plate, said
  • a hydraulic mine prop comprising, in combination, an external tubular prop element having an axis and being closed at one end; an internal prop member having an end portion projecting with clearance into said external tubular prop element and being movable toward and away from said closed end of the latter; a piston member located adjacent the inner end of said internal prop member and sealingly engaging the inner surface of said external prop element to form therewith a pressure chamber, one of said members being formed at a portion thereof facing the other of said members with a cavity having a plane end surface transverse to said axis and a peripheral surface; a first abutment plate located in said cavity and having a plane surface engaging said plane end surface of said cavity and having opposite said plane surface a spherically curved surface and a peripheral surface spaced from said peripheral surface of said cavity; a second abutment plate sandwiched between said first abutment plate and the other of said members, said second abutment plate having a pair of spherically curved surfaces extending transverse to said axis, one of which
  • a hydraulic mine prop comprising, in combination, an external tubular prop member having an axis and being closed at one end; an internal tubular prop member having an end portion projecting with clearance into said external prop member and being movable toward and away from said closed end of said external prop member, said internal prop member including end wall means fixed to said end portion thereof and being closed at the end opposite said end portion; piston means supported on said end wall means of said internal prop member and sealing- I 1y engaging the inner surface of said external prop mem ber to form therewith between said piston means and said closed end of said external prop member a pressure chamber; connecting means for connecting said piston means and said end wall means of said internal prop member for simultaneous movement toward and away from the closed end of said external prop member and for limited universal tilting movement relative to each other, said connecting means including passage means for providing communication between said pressure chamber and the interior of said internal prop member; and means for feeding pressure fiuid in and out of said space formed by the communicating pressure chamber and the interior of said internal prop member.
  • passage means include conduit means fluid-tightly connected at opposite ends thereof to said end Wall means and to said piston means.
  • passage means include an elastic high pressure hose formed at opposite ends thereof with beads fluid-tightly connected to said piston and said end wall means, respectively.
  • said passage means include a substantially rigid tube, preferably formed from metal.

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Mechanical Engineering (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Refuge Islands, Traffic Blockers, Or Guard Fence (AREA)
  • Actuator (AREA)
  • Forging (AREA)
US243199A 1960-02-19 1962-12-04 Hydraulically operable mine prop Expired - Lifetime US3172340A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEB56733A DE1198306B (de) 1960-02-19 1960-02-19 Hydraulischer Grubenstempel

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US3172340A true US3172340A (en) 1965-03-09

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US243199A Expired - Lifetime US3172340A (en) 1960-02-19 1962-12-04 Hydraulically operable mine prop

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US (1) US3172340A (en(2012))
AT (1) AT250271B (en(2012))
BE (1) BE600368A (en(2012))
DE (1) DE1198306B (en(2012))
GB (1) GB961983A (en(2012))
NL (1) NL261134A (en(2012))

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3313347A (en) * 1963-01-09 1967-04-11 Gray Tool Co Well completion procedures and apparatus
US3395619A (en) * 1965-08-23 1968-08-06 Grebe Konrad Hydraulic propping apparatus with automatic overload protection means
US3930437A (en) * 1973-03-20 1976-01-06 Von Roll Ag Piston structure, particularly for hydraulic machines
US4051924A (en) * 1975-10-15 1977-10-04 Yoshigai Kikai Kinzoku Kabushiki Kaisha Device for mounting brake shoe of brake for bicycle
US4142449A (en) * 1976-02-03 1979-03-06 Thyssen Industrie Ag Hydraulic mine prop
US4699572A (en) * 1981-08-13 1987-10-13 Commonwealth Scientific And Industrial Research Organization Reciprocatory piston and cylinder machine
US5205382A (en) * 1990-10-09 1993-04-27 The B. F. Goodrich Company Aircraft brake
US5413031A (en) * 1994-01-06 1995-05-09 Parker-Hannifin Corporation Alignment coupler for linear device

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE918561C (de) * 1951-08-08 1954-09-30 Arthur Hamel Hydraulischer Grubenstempel
DE1012275B (de) * 1953-09-09 1957-07-18 Coal Industry Patents Ltd Grubenstempel
GB772543A (en) * 1954-06-26 1957-04-17 Gullick Ltd Improvements in or relating to props, chocks, and like roof supporting structures
DE1009137B (de) * 1955-12-14 1957-05-29 Hermann Schwarz K G Hydraulischer Grubenstempel mit rohrfoermigem Innen- und Aussenteil

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3313347A (en) * 1963-01-09 1967-04-11 Gray Tool Co Well completion procedures and apparatus
US3395619A (en) * 1965-08-23 1968-08-06 Grebe Konrad Hydraulic propping apparatus with automatic overload protection means
US3930437A (en) * 1973-03-20 1976-01-06 Von Roll Ag Piston structure, particularly for hydraulic machines
US4051924A (en) * 1975-10-15 1977-10-04 Yoshigai Kikai Kinzoku Kabushiki Kaisha Device for mounting brake shoe of brake for bicycle
US4142449A (en) * 1976-02-03 1979-03-06 Thyssen Industrie Ag Hydraulic mine prop
US4699572A (en) * 1981-08-13 1987-10-13 Commonwealth Scientific And Industrial Research Organization Reciprocatory piston and cylinder machine
US4790726A (en) * 1981-08-13 1988-12-13 Commonwealth Scientific And Industrial Research Organization Reciprocatory piston and cylinder machine
US5205382A (en) * 1990-10-09 1993-04-27 The B. F. Goodrich Company Aircraft brake
US5413031A (en) * 1994-01-06 1995-05-09 Parker-Hannifin Corporation Alignment coupler for linear device

Also Published As

Publication number Publication date
GB961983A (en) 1964-06-24
DE1198306B (de) 1965-08-12
AT250271B (de) 1966-11-10
NL261134A (en(2012))
BE600368A (en(2012))

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