US 3224202 A
Description (OCR text may contain errors)
j n. 21, 1965 A. DURGET 3,224,202
ANCHORING DEVI GE Filed May 16, 1962 Sheets-Sheet 1 FIG] Deb. 21, 1965 A. DURGET 3,224,202
ANGHORING DEVICE Filed May 16, 1962 ZShGBbS-SIIGG; 2
United States Patent 3,224,202 ANCHORING DEVICE Andr Durget, Paris, France, assignor to Anciens Etablissements Goldenberg & Cie, Saverne, Bas-Rhin, France Filed May 16, 1962, Ser. No. 195,291 Claims priority, application France, May 23, 1961, 862,583, Patent 1,297,817 2 Claims. (Cl. 61-45) The present invention relates to anchoring such as that employed in mines for supporting roofs and strengthening the facings of galleries.
According to known techniques for achieving the above, a boring is made in the ground and an anchoring device provided with an expanding head is inserted therein and fastened to the walls of the bore. The expansion of this head is controlled by a rod extending out of the bore and bearing against a metal anchoring plate which bears against the face of the ground. This face is most often irregular in shape and it is diflicult to achieve a sound contact between the face and the anchoring plate and yet the quality of this contact affects the efiiciency of the anchoring, since it is through the anchoring plate that the applied pressure is transmitted to the ground. An insufficient contact is manifested by a bad distribution of the pressure which can reach very high local values. These cause the rocks of the ground to break up and this renders the anchoring uncertain.
An object of the invention is to remedy this drawback and to this end, invention provides a method of mounting anchoring devices in the ground, said method comprising interposing between the face of the ground in which the anchoring device is inserted and the anchoring plate against which said device bears, a coherent and deformable layer of an incompressible granular material which conforms to the shape of said face.
With this method a perfect contact is obtained in all cases, irrespective of the shape of the face, between the anchoring plate and said face. The layer of incompressible material forms a filling which molds itself to the face of the bore while insuring, due to its very nature, a full and uniform transmission of the pressure exerted by the anchoring device.
The granular material employed to form this layer is advantageously sand agglomerated by any suitable binder. This layer can be placed in position when anchoring or previously provided on the anchoring plate itself. Thus, according to another feature of the invention, the latter provides an anchoring plate having on the face thereof adapted to come in contact with the ground a coherent and deformable layer of an incompressible granular material molded on the plate.-
Further features and advantages of the invention will become apparent from the ensuing description, with reference to the accompanying drawings to which the invention is in no way limited.
In the drawings:
FIG. 1 is a diagrammatic cross-sectional view of a mine gallery shown as an illustration of an anchoring method according to the invention;
FIG. 2 is a view similar to FIG. 1 on an enlarged scale of a detail of FIG. 1 illustrating one manner of carrying out the method of the invention;
FIG. 3 is an axial sectional view of a plate provided with a filling layer according to the invention;
FIG. 4 is a view of the plate shown in FIG. 3 in service, and
FIGS. 5-8 are views similar to FIG. 4 of four modifications of the plate according to the invention.
FIG. 1 shows a mine gallery 1 having a roof 2 in which are provided bores 3 through soft layers 4 of the ground so as to reach a hard layer 5. An anchoring device A is inserted in each of these bores. This device comprises an expanding head 6 that a rod 7 causes to expand when it is subjected to a tractive force by a nut 8 which is threadedly engaged on its outer screwthreaded end. To achieve this traction the nut 8 bears against a saucershaped plate P through which extends the rod 7 and which bears against the face of the bore. The head 6 thus fastens itself into the hard layer of the ground and the anchoring device supports the subjacent soft layers. This method is known as a suspended roof support or roof bolting. Its efliciency depends on obtaining a satisfactory contact between the plates P and the roof 2 constituting the face of the bores 3. Now, this roof has an irregular profile and it is diflicult to obtain a satisfactory support for the plates P. To overcome this difiiculty there is inserted according to the invention between each plate P and the face of the corresponding bore a filling layer C which is best seen in FIG. 2. This layer C rests on the face of the plate P, in the presently-described embodiment in the form of a cup, and has an axial hole 9 in vertical alignment with the hole 10 in the plate P for the passage of the rod 7.
The layer C is composed of an incompressible granular material rendered coherent. This material is advantageously sand agglomerated by any suitable plastic-type binder such as bitumen, rubberized binder or other plastic material binder. By way of example, there can be used sand having a grain size of 0-5 mm. agglomerated by bitumen of grade 40-60. A rubber latex could also be used as the binder. The aforementioned indications are purely illustrative, since a large number of commercially available binders can be used, even sand having a different grain size. Similarly, although sand is preferred owing to its abundance and low cost, granulated materials having similar properties could be substituted therefor.
The interposed layer C results in a close contact between the plate P and the face 2 of the bore, since when the nut 8 is screwed along the rod this layer molds itself to the face 2 and fits around the asperities. Owing to its very nature the layer 2 wholly and uniformly transmits all the pressures exerted thereon by the plate P.
Two methods are available for applying the layer C. The first method is that shown in FIG. 2 and comprises applying the layer C when anchoring by spreading the agglomerated granular material over the saucer-shaped plate P. The other method is that shown in FIGS. 3-8 in which the layer C is previously applied on the anchorin-g plate with which it constitutes a unit. This second method has the advantage for the operator of not com-' FIG. 3 shows a saucer-shaped plate P having a profile different to the late P and in which the layer C is applied by molding. It will be noted that the passage 9a for the passage of the rod 7 is more tapered than in the preceding embodiment and this precludes jamming of the threading of this rod.
FIG. 4 shows the plate illustrated in FIG. 3 placed in position, the upper face of the layer C, which was initially flat, having been caused to conform to the face 2 of the bore in the course of the screwing of the nut 8 along the rod 7.
FIG. 5 shows another type of saucer-shaped plate P whose layer C has been previously applied on the plate. This permits providing at the upper end of the passage 9b a part-conical recess 11 forming a free space for the flow of the material of which the layer C is composed.
The saucer-shaped plate P shown in FIG. 6 has a central portion '12 in'the form of a hollow conical dome connected to the periphery of the plate by a pressed out intermediate portion 13. This arangement is adapted in the known manner to provide a controlled deformability of the plate P Further, it allows a suitable orientation of the anchoring device in the case of an inclined bore 3. To this end, a washer 14 is inserted in the dome 12 between the hole in the latter and the nut 8. This washer is capable of blocking itself in the dome in accordance with the orientation of the rod relative to the axis of the hole 10 so as' to adapt itself to the inclination of the bore 3 relative to the face 2 of the ground. This presupposes that the rod 7 can itself take up an inclined position in the hole 10 which is provided large enough for this purpose and the passage9c formed in the layer C above the hole 10 is of suitable section. The molding of the layer C on the requirement.
FIG. 7 shows a saucer-shaped plate P also permitting an orientation of the rod 7 in accordance with the inclina-' tion of the bore 3 which is shown greatly inclined relative to the face 2. The plate P comprises a central hemispherical boss provided with a large slot 16 in a diametral dane. Disposed on the boss 15 is a washer 17 also hemispherical in shape, the boss 15 and the washer 17 constituting a swivel joint assembly. The passage 9d formed in the layer C in alignment with the slot 16 has a sufiicient extent to permit all the possible angular movements of the rod 7 in the course of the swiveling of the latter.
FIG. 8 shows a saucer-shaped plate P also permitting a suitable orientation of the rod 7. The plate P comprises a central bearing portion 18 in which is rotatably mounted a cup 19 provided with a slot 20 in a diametral plane. The nut bears on the cup 19 through the medium of a curved washer 21. Here again, owing to the large possibilities of orientation afforded by the plate P the passage 9c has a great extent. I
The various possibilities of the method according to the invention will be quite clear. While insuring a uniform distribution of the pressures owing to its adaptation to the ground, the filling layer C does not interfere in any way with the usual operation of the anchoring plates.
Apart from the adaptation of the anchoring face to the ground, the layer C affords various additional advantages. the bores 3 from the atmosphere of the galleries 1 which, especially in the case of marls, diminishesthe danger of swelling owing to entry of air. Moreover, the relative fluidtightness thus obtained precludes the trickling onto the plates often observed at the present time. The corrosion of the plates is reduced owing to the interposition of the inert material of the layer C between the roof and the plates.
Although specific embodiments of the invention have been described, many modifications and changes may be plate P permits meeting the last Thus this layer insulates the atmosphere of.
made therein without departing from the scope of the invention as defined in the appended claims.
What is claimed is:
1. An anchoring device comprising a saucer-shaped anchoring plate having a centural opening therein, an anchoring member extending through said opening and adapted to engage in a ground-constituted roof to suspend said plate therefrom, said plate having a face in facing relation with the ground-constituted roof, and a coherent, solid and plastic-type deformable mass on said face of the plate, said mass being constituted by an incompressible and non-deformable granular material and a plastic-type deformable binder in which the granular material is embeded, said mass having a thickness whereby to project from the plate for encountering and conforming to the contourof said roof and preventing the plate from encountering the roof, said mass being generally I shape retaining but being deformable under compression to the extent permitted by compacting said non-deformable material, said binder being bitumen.
2. An anchoring device comprising a saucer-shaped anchoring plate having a central opening therein, an anchoring member extending through said opening and adapted to engage in a ground-constituted roof to suspend said plate therefrom, said plate having a face in facing relation with the ground-constituted roof, and a coherent, solid and plastic-type deformable mass on said face of the plate, said mass being constituted by an incompressible and non-deformable granular material and a plastic-type deformable binder in which the granular material is embedded, said mass having a thickness whereby to project from the plate for encountering and conforming to the contour of said roof and preventing the plate from encountering the roof, said mass being generally shape retaining but being deformable under compression to the extent permitted by compacting said non-deformable material, said binder being a rubberized binder.
References Cited by the Examiner UNITED STATES PATENTS 1,817,033 8/1931 Ross 94-182 2,000,978 5/1935 MOSClGY 94 1 2,603,573 7/1952 1310a l06281 x 2,682,152 6/1954 Biel'el 61-45 2,748,594 6/1956 Edwards 61-45 3,086,421 4/1963 Hamman -1 FOREIGN PATENTS 924,624 3/1955 Germany.
842,078 7/1960 Great Britain. 1,222,640 6/1960 France.
CHARLES E. OCONNELL, Primary Examiner.
JACOB L. NACKENOFF, RICHARD W. COOKE, 111.,
FRANK L, ABBOTT, Examiners,