FR2671829A1 - DEFORMABLE CEILING SUPPORT SYSTEM ESPECIALLY FOR GALLERIES OF MINES. - Google Patents

Abstract

This support (10) comprises a base member (12) having an open end (14) and a hollow interior (1.6), a push member (18) having one end (22) passing through the open end (14) of the base member (12), in its hollow interior (16) and having, on it, threads (20), and a mandrel (40) or sliding nut, capable of coming into contact with the threads (20) of the pusher (18), in an adjustable position and producing an interfering relationship between the base (12) and the pusher (18), when a compressive load is applied thereto. The support (10) is particularly suitable for supporting the ceiling of a mine.

Description

The invention generally relates to supports, and more particularly

  a medium liable to deform in a controlled manner, in response to the application

a charge.

  Mining, particularly for long-tunnel mines, requires a ceiling support, or sky, which deforms

  controlled, in response to the loads exerted by the ceiling.

  In the past, mine operators have used column-type ceiling supports in the form of wooden frames and pillars. The frames absorb the initial load of the ceiling and the pillars deform when a load is applied to them. This type of roof support system is an attempt to approach an ideal system, which would be very rigid with respect to the influence of the initial load and which would still have the same effect. possibility of deforming in a controlled way However, the frames and pillars pose a risk of fire, are expensive and require a lot of work The frames and pillars also occupy a relatively large volume in the space and can thus interfere with the ventilation and complicate the movement of materials and personnel indoors and

out of the mine.

  A deformable steel pillar, for use in shoring or supporting a mine roof, is described in Coal Magazine, June 1990, pages 136 and 167 the pillar comprises a lower leg, telescopically mounted in an upper foot, wherein each foot includes a length of tubing A conical expansion ring is welded to the lower leg at a desired location, and lower and upper plates are welded to the lower and upper legs and adapted to contact the ground and the ceiling, respectively, of a "mine" When a compressive load is applied to the pillar, the expansion ring deforms radially the upper foot, outwardly, when the latter moves relative to the lower foot. A deformable ceiling support according to the prior art uses a split top foot, consisting of a hollow tube, telescopically mounted within a lower leg, which is also a hollow tube A wedge is driven into the slot in the upper foot in a desired location The wedge causes an interference connection to the lower foot at the upper foot, at this location When a load is applied to the support, the foot lower is deformed radially by the upper section of the foot,

the location of the corner.

  Another type of deformable pillar is sold by Jenmar Corp. of Pittsburgh, Pennsylvania This type of ceiling support includes an upper profile fitted into a lower profile and one or more crampons, which

  connect the upper and lower profiles together.

  Other types of ceiling supports include skids or pillars, and are described in an article published in

  in Coal Age, March 1987, pages 30 to 33.

  None of the pillar type ceiling supports,

  above, has proved to be entirely satisfactory in terms of cost, ease of manufacture and assembly and

of propensity to shoring.

  In addition to the pillar-type supports, the anchor type deformable ceiling supports for tunnels and the like have been designed in which a support rod extending into the surface of the tunnel rock includes a deformation member, carried at one end on the rod, in axial alignment with respect to a steel tube When the rod is energized, the deformation member is inflected inside the steel tube, so as to deform the tube radially outwards and to allow limited movement of the rod.

  design is described in Australian Patent 378,823.

  West German Application 33 14 858 A1 discloses a deformable ceiling support which comprises a rod which has a series of stepped portions, separated by portions, conical at one of their ends, arranged in a steel tube. Stepped sections and tapered deform the steel tube radially outwards

  when the rod is energized.

  According to the invention, a deformable support, for a compressive load, is capable of deforming in a controlled manner, when a load is applied to it, and is easily adaptable to many conditions.

different loads.

  More particularly, this support comprises a base member having an open end and a hollow interior, a thrust member having an end passing through the open end of the base member, in its hollow interior and comprising threaded portions and means engageable with the threaded portions of the biasing member, in an adjustable position, for producing an interference relationship between the basic and thrust members when applied thereto;

a compressive load.

  Preferably, according to one aspect of the present invention, the interference means comprises a tapered mandrel, provided, within it, with a tapped bore, in

  contact with the threads formed on the pushing member.

  Also preferably, the mandrel and the base member have a circular cross section, the base member having a first inside diameter value along its length and the mandrel having a second outside diameter value less than the first value. at its other end Furthermore, according to the preferred embodiment, the outer diameter of the mandrel increases linearly from the second value,

  to the third value, over part of its length.

  If desired, a means may be supported by the thrust member and disposed within the base member to center the thrust member when relative movement occurs between the members , in

  response to the application of a load on these.

  According to one aspect of the present invention, the centering means comprises a cylindrical nut, arranged on the

  threaded parts of the thrust member.

  Still according to this aspect of the present invention, the thrust member comprises a threaded rod and the base member comprises a tube, radially expanded by the thrust member during the relative movement of the

organs.

  According to another aspect of the present invention, the interference means comprises a sliding nut and the base member has a first inside diameter value and has a lower load bearing capacity and the sliding nut has a second value of outside diameter and greater than the first value Preferably, the sliding nut comprises, within it, a bore, provided with tappings in contact with the threads of the thrust member, in which the threads of the thrust member are having a first shear strength and the tapped holes of the bore have a second shear strength, greater than the first shear strength, so that the tapped holes of the bore shear the threads of the shear member. thrust, when a load is applied to the organs. Preferably, a means is supported by the thrust member and disposed inside the base member, to ensure the centering of the thrust member, when a relative movement takes place between the organs, in response to the application of a load on the latter According to this aspect of the invention, the sliding nut and the end of the base member are of complementary shapes, for

  help the centering of the pushing member.

  In addition, there may be provided a means for limiting the movement of the organs, the limiting means comprising

  a nut supported by the thrust member.

  The support according to the invention is of a simple and effective design, to ensure a deformable support compression loads Its length can also be easily adjusted, so as to adapt to

  mine ceilings of different heights.

  FIG. 1 represents an elevational view, partially in section, of a support according to the present invention, before application to the latter of the load; FIG. 2 represents a view similar to FIG. 1, of the support according to the invention, after application of the load to the latter; Figure 3 shows a sectional view of the base member of Figures 1 and 2; Fig. 4 shows a plan view of the base member; Figure 5 shows a sectional view of the top plate of Figures 1 and 2; Figure 6 is a bottom view of the top plate of Figure 7; Figure 7 shows a partial sectional view of the mandrel of Figures 1 and 2; Figure 8 shows a plan view of the mandrel; Figure 9 shows a partial sectional view of the cylindrical nut of Figures 1 and 2; Figure 10 shows a plan view of the cylindrical nut; Fig. 11 shows a view, similar to Fig. 1, of another embodiment of the present invention; Fig. 12 is a fragmentary elevational view, partly in section, of an alternative embodiment of Fig. 11; FIG. 13 represents an elevational view of yet another embodiment of the present

invention.

  Referring now to FIG. 1, a support, for supporting a compressive load, such as the ceiling or sky of a mine, comprises a base member 12 comprising an open end 14 and a hollow interior 16, and a push member 18, in the form of a rod, provided all around a series of threads 20, in which a first end 22 of the rod extends into the first end 14 of

  the base member 12, in the hollow interior 16.

  Referring to FIGS. 3 and 4, the base member 12 may comprise an ordinary tube section. In one example of the present invention, adapted to support a particular ceiling load, the base member 12 comprises a steel tube. seamless or butt welded carbon, constructed in accordance with one or more of the standards ASTM A 53, A 106 and A 120, in annex 40 welded at a second end 24 of the base member 12, a plate steel bottom 26 is adapted to rest on the ground of

the mine.

  Referring now to FIGS. 5 and 6, an upper plate 28 is welded to a locknut 30 which has a series of threads 32 surrounding a bore 34. The threads 32 receive the threads 20 of the stem 18 placed on its second thread. end 36 The upper plate 28 is adapted to come into contact with the

ceiling of the mine.

  It should be noted that the lower plate 26, the upper plate 28 and the lock nut 30 are optional, in the sense that the base member 12 and the rod 18 can be attached to a floor and a ceiling of a mine or other structures, such as a lattice, by means

different, if you wish.

  Referring again to FIG. 1, a means in the form of a mandrel 40 is capable of coming into contact with the threads 20 of the rod 18 at an adjustable location and produces an interference relationship between the base member 12 and the rod 18, when a compressive load is applied to it. More specifically, and with reference to FIGS. 7 and 8, the mandrel 40 comprises a through bore 42, with threads 44, whose dimension allows The mandrel 40 is preferably of circular cross-section and comprises a first end 46, of a first diameter, and a second end 48, of a second diameter, and an intermediate portion. Preferably, the diameter of the intermediate portion 50 increases linearly (i.e. uniformly) from the first diameter 46 to the second diameter 48, although the diameter may increase differently than linearly, if e wishes the mandrel 50 thus comprises an outer surface 52 conical and forming a certain angle with respect to the longitudinal axis

54 of the chuck 40.

  If desired, planar or flat surfaces 55 may be provided on the mandrel 40. The planar surfaces allow the mandrel 40 to be brought into contact with a tool (not shown) so that the mandrel can be rotated to allow its position on the rod 18 to be adjusted This in turn allows the height of the support 10 to be adjustable in order to be able to use the support 10 to support ceilings

mine of different heights.

  On the first end 22 of the rod 18 is disposed a means, which is in the form of a cylindrical nut 60, to ensure the centering of the rod 18, when a relative displacement occurs between the rod and the tube, in response to the application of a compressive load The cylindrical nut 60 is made of any suitable material, such as metal or plastic, and is shown in more detail in FIGS. 9 and 10. The nut 60 comprises an internal bore 62, with threads 64, adapted to receive the

threads 20 located on the rod 18.

  In the preferred embodiment, mandrel 40 is made of ductile iron 80-55-06, ASTM A 536-80 BHM 197/255. Rod 18 is THREADBAR No. 18, sold by Dywidag Systems International, USA, Inc. , located in Lemont, Illinois, a subsidiary of the Applicant of the present application, although a different size of rod may be used, if desired Also, according to an example of the present invention, the different parts have the dimensions indicated in FIG. Table A below, although it should be noted that the dimensions indicated below are optional and are not considered as limiting the scope of the present invention (the reference letters are indicated in the figures and all dimensions are

  data in inches, and in mm, unless otherwise indicated).

Table A

  Reference letter dimension dimension in inches in mm

A 36,000 * 914.40

B 0.500 12.70

C 4,000 101.60

D 3.548 90.12

E, 6,000, 152.40

F 0.500 12.70

G 2,000 50.80

H, 6,000, 152.40

I 3,250 82.55

J 4.535 115.16

K 2,248 57.10

L 5,000 127,00

M 1.000 25.40

N, 3,000, 76.20

O 1,000 25.40

P 3.423 86.94

Q 10.5 degrees 10.5 degrees

R, 3,423, 86.94

S 0.63 16.00

T 0.125 3.17

U 2,000 50.80

V 2,248 57.10

  * The lengths of the base member 12 and the stem 18 depend on the height, above the floor, of the ceiling

  and vary with the specific installation.

  Referring again to FIGS. 1 and 2, before the stem 18 and the base member are subjected to a compressive load, the rod 18 is inserted into the base member 12, so that the nut cylindrical 60 and a portion of the mandrel 40 are disposed inside 16 of the base member 12 As already noted, the height of the support 10 is adjusted by rotation of the mandrel 40, so that the support 10 is disposed between and in contact with the floor and the ceiling of the mine. When a compression load is applied on the rod 18 and the base member 12, there is a relative displacement between the rod 18 and the base member 12, in the axial direction. This relative displacement causes the radial deformation of the rod. base member 12, due to the interference of the mandrel 40 The radial deformation allows the support 10 to deform, in response to the applied loads, in a controlled manner, which prevents any catastrophic rupture of the support 10 During the relative movement of the the stem 18 and the base member 12, the cylindrical nut 60 acts to maintain the rod 18 centered within the base member 12. As can be seen with reference to FIG. of the support 10 before the relative displacement of the rod 18 and the base member 12 can be adjusted by a rotation of the mandrel 40 on the threads 20, so as to change its position in height The support 10 can thus be easily adapted to different high ceiling,

as much as necessary.

  The material of the base member 12 and the relative dimensions of the mandrel 40 and the base member 12 are chosen so that the maximum support load of the support 10 is less than their calculated buckling capacity, by adopting the margin In the same way, the angle Q, shown in the drawings, can be of any value, offering the desired capacity of resistance to the load, although angles in the range of 7 to 15 degrees have been found

give the best results.

  When a compressive load is first applied, the mandrel 40 transmits a radially outwardly directed force against the walls of the base member 12. The walls of the base member 12 deform when the load is applied until the elastic resistance limit of the base member 12 is reached Then the support 10 deforms and provides a substantially constant and continuous upward force of load resistance applied, until the entire deformation travel of the support 10 is traveled. FIG. 11 illustrates an alternative embodiment of the present invention. The elements common to FIGS. 1 to 10 and 11 are provided with the same reference numerals. As in the previous embodiment, the rod 18 extends into the hollow interior. In this embodiment, the base member 12 must have a load capacity greater than the breaking load limit of the rod 18. Similarly, the threaded shank is received inside the body. The sliding nut 70 has a reduced diameter portion 72, which is received within the first end 14 of the base member 12, and a second portion of enlarged diameter. 74, disposed above the end 14 and having a diameter at least equal to the inner diameter of the base member 12 The first end of the base member 12 and the sliding nut 70 are of complementary shape, to help at centering the rod 18 inside of

  the base member 12 during their relative movement.

  Referring to Figure 12, the slide nut 70 may be replaced by a different slide nut, which has a rounded lower surface 82, which is received within a cylindrical seat 84 formed on the end walls. of the base member 12 Again, the sliding nut and the end 14 of the base member 12 are of complementary shapes, to help centering the rod 18 within the base member Each of the slide nut 70,80 includes tappings 90 which are of a shape to engage the threads 20 on the rod 18 Preferably, although not necessary, and as shown in FIG. 12, the threads 20 do not extend continuously on the shank 18 Instead, the threads 20 are discontinuous in the thread without adjacent threads 20 are separated from each other in one or more zones 91 which extend axially on the rod 18 The nets 90 prese The shear strength is greater than the threads 20, so that when a compressive load is applied to the rod 18 and the base member 12, the threads 90 successively cut threads 20. relative movement of the rod 18 and the base member 12, in response to the application of a load, so that the support deforms in a controlled manner, in response to the application of the load. It can be seen that, as in the previous embodiment, deformation is enabled by interference that occurs between members that can move relative to each other, so that the charges can be supported without producing a break

catastrophic support.

  More particularly, the supports of FIGS. 11 and 12 resist deflection until a load of sufficient magnitude is applied to shear off one of the threads. compression then drops and then increases until a magnitude of

  load that causes shearing of the next net 20.

  The strength of resistance then increases and falls once the threads 20 have been sheared, allowing the

  support to deform in a controlled manner.

  If desired, an optional safety nut 100 may be screwed onto the rod 18, at a suitable height, so as to limit the movement of the rod 18 and the support member 12 The safety nut 100 is designed to support a load that exceeds the breaking load

of the stem 18.

  It should be noted that projections other than threads may be used to produce the interference fit between the slide nut 70 or 80 and the rod 18, if desired. Similarly, a different complementary mount may be used between sliding nut 70

or 80 and the base member 12.

  It should be noted that the sliding nut 70 or 80 and the rod 18 may be supported by any other structure having an orifice or through opening, to allow movement of the rod 18 In any case, the support structure is preferably capable of withstanding a load exceeding the breaking load of the rod 18 Thus, for example, Fig. 13 illustrates an alternative embodiment of the present invention, in which the support of Figs. 11 and 12 may be used, together with posts in conventional wood or concrete pads, to support a load by providing a deformation capacity The embodiment of FIG. 13 provides greater resistance against buckling, in comparison with the embodiment of FIGS. 11 and 12 More specifically, one or more threaded rods 18 are arranged inside one or more sliding nuts 70 or 80, which are, in turn, arranged on collars 108 A The series of wooden posts or concrete pads 110 are stacked under the rods 18, the sliding nut 70 or 80 and the collars 108, and comprise within them openings or holes 112 aligned with the upper plates 128 attached to the rods. 18 by nuts 136

  welded to them, are arranged above the rods 18.

  When a load from the ceiling is applied to the rods 18, on the plates 128, the sliding nuts 70 or 80 shear the threads on the rods 18, as previously The rods 18 thus extending into the

  holes 112 formed in the posts or skids 110.

  The embodiment of Fig. 13 has the advantage that only a relatively short length of rod 18 is needed and that a race of

high deformation.

  It should be noted that multiple supports, in accordance with the present invention, can be used together and that they can be connected between a common upper plate and a common lower plate, to form an assembly.

  multiple, which supports a compression load.

  Many modifications and embodiments of the invention will be obvious to the man of

  art, in view of the description above.

  this description is for illustrative purposes only

  and for the purpose of teaching those skilled in the art the best mode of implementation of the invention The details of the structure can be modified significantly, without

to leave the spirit of the invention.

Claims (22)

RESUME ICAT IONS   A support comprising: a base member (12) having an open end (14) and a hollow interior (16), a thrust member (18) having an end extending through the open end of the base member, in its hollow interior (16) and having threaded portions, and means capable of coming into contact with the threaded portions of the thrust member (18), in an adjustable position, to produce a relationship of interference between the basic and thrust members (12, 18) when a compressive load is applied to them. 2 Support according to claim 1, wherein the interference means comprises a tapered mandrel (40) having, within it, a tapped bore, in contact with   the threads (20) formed on the thrust member (18).   The carrier of claim 2, wherein the mandrel (40) and the base member have a circular cross-section, the base member having a first inside diameter value along its length, and the mandrel (40) having a second outer diameter value, smaller than the first value, on its other end. 4 Support according to claim 3, wherein the outer diameter of the mandrel (40) increases linearly from the second value to the third value, on a portion (50) of its length.   Support according to claim 1, further comprising means supported by the thrust member (18) and disposed within the base member for centering the thrust member (18), when a relative movement takes place between the organs, in response to   the application of a load on these.   6 Support according to claim 5, wherein the centering means comprises a cylindrical nut (60) disposed on the threaded portions of the thrust member (18).   Support according to claim 1, wherein   the thrust member (18) comprises a threaded rod.   8 Support according to claim 1, wherein the base member comprises a tube, radially expanded by the thrust member (18) during the relative movement of the organs. 9 Support according to claim 1, wherein the   interference means comprises a sliding nut (70).   A carrier as claimed in claim 9, wherein the rod has a rupture limit and the base member has a first inside diameter value and has a load carrying capacity (10) lower than the rod break limit, and the sliding nut (70) has a second outer diameter value and greater than the first value.   11 Support according to claim 10, wherein the sliding nut (70) comprises, within it, a bore, having threads (32) in contact with the threads (20) of the thrust member (18), in wherein the threads (20) of the thrust member (18) are provided with a first shear resistance and the threads (32) of the bore are provided with a second shear strength, greater than the first resistance in shear, so that the threads (32) of the bore shear the threads (20) of the thrust member (18), when a load is applied to the members.  12 Support according to claim 11, further comprising a means supported by the thrust member (18) and arranged inside the base member, to ensure the centering of the thrust member (18) when a relative movement takes place between the organs, in response to   the application of a load on these.   13 Support according to claim 12, wherein the sliding nut (70) and the end of the base member are of complementary shapes, to help the centering of the pushing member (18).   The carrier of claim 13, wherein the limiting means comprises a nut supported by the pushing member (18).   A ceiling support for a mine comprising: a tube (12) having a first (14) and a second (24) end and a wall defining a channel (16) of circular cross-section therein , having a substantially constant diameter along its length, a rod (18) having first (22) and second (36) ends and threads (20), around its outer periphery, a mandrel (40) having a bore therein threaded (42), in contact with the threads (20) on the rod (18), so that the mandrel (40) can be positioned at a desired point on the rod, driving the mandrel (40) in relative rotation , relative to the shank (18), the mandrel (40) further comprising an outer surface having a first diameter smaller than the substantially constant diameter (48) at its first end (46) and a second diameter greater than the substantially constant diameter at its second end (48), located opposite its first end (46), wherein the first end (22) of the rod (18) passes through the first end (14) of the tube (12) and the mandrel (40) is disposed, at least in part, inside the channel (16) of the tube (12), so that its outer surface is in interference contact with the walls of the tube (12), and upper (28) and lower (26) plates. ), disposed on the second ends (36,24) of the rod (18) and the tube (12), respectively, and adapted to come into contact with the ceiling and the floor of a mine, respectively.  Ceiling support according to claim 15, further comprising a cylindrical nut (60), supported by the rod (18) and disposed within the tube channel (16), for centering the the rod (18), when relative movement takes place between the rod (18) and the tube (12), in response to the application of a load on these latter.   A ceiling support according to claim 15, wherein the mandrel (40) has a longitudinal axis and the mandrel outer surface (40) comprises a tapered intermediate portion (56) having a uniformly increasing diameter and disposed with way to train   a certain angle (Q) with the longitudinal axis.   The ceiling support according to claim 17, wherein the certain angle (Q) is in the range ranging from 7 to 15 degrees.   Ceiling support according to claim 18,   wherein the certain angle (Q) is equal to 10.5 degrees.   Ceiling support according to claim 15, wherein the substantially constant diameter is equal to   , 1 mm and the second diameter is equal to 115.2 mm.   Ceiling support according to claim 20,   wherein the first diameter is 86.9 mm.   22 A ceiling support for a mine, comprising: a support structure (12) having a support surface and an opening (16) therein, a stem (18) having first (22) and second (36) ) the ends and a projection (20) around its outer periphery, the projection having a first shear strength, a sliding nut (70,80) having a bore therein and having a portion (90) therein in contact with the projection (20) on the shank (18) so that the portion (90) of the slide nut (70,80) has a second shear strength greater than the first shear strength, wherein the first end (22) of the rod (18) extends into the opening (16) and the sliding nut is disposed in contact with the support surface (12) of the support structure (10), and upper (28) and lower (26) plates disposed on the second ends ( 36, 24) of the rod (18) and the support structure (10), respectively, and adapted to come into contact with a ceiling and a floor of a mine, respectively.   Ceiling support according to claim 22, wherein the support structure (10) comprises a tube (18).   Ceiling support according to claim 23, further comprising a sliding nut (60) supported by the shank (18) and disposed within the channel (16) to center the shank (18), when a relative movement takes place between the rod (18) and the tube (12).   Bottom support according to claim 22, wherein the support structure (10) comprises wooden pillars (110).   The ceiling support according to claim 22, wherein the support structure (10) comprises concrete pads (110).   Ceiling support according to claim 22, wherein the shank portion on the shank (18) comprises a series of threads (20) and wherein the threads (20) are sheared by the shank (18) when relative movement takes place between the rod and the support structure system (12), in response to the application   a compressive load on these.   A ceiling support according to claim 22, wherein the slide nut (70) and the support surface (12) are of complementary shapes to assist in centering of the rod (18).   Ceiling support according to claim 22, further comprising means for limiting the relative movement of the shank (18) and the support structure (12).   Ceiling support according to claim 29, wherein the limiting means comprises a nut (100) supported by the rod (18).