US 3726181 A
Mine roof expansion shell assembly having a one piece shell with annular ring and four expansion fingers with external gripping teeth extending from the ring, and an internal flat wedge engaging surface adjacent the other end, an expanding wedge having a threaded aperture for a mine roof bolt and wedge faces for each of the fingers, the fingers being spaced apart on opposite sides of the shell to form a slot for a wedge retaining U-shaped strap extending over the large diameter end of the wedge with its ends extending through the ring in grooves aligned with the slots, the ends being bent outwardly to engage the underside of the ring, the bent ends being held in place by resiliency of the strap, or the presence of a mine roof bolt threaded into the wedge, and extending through the ring.
Description (OCR text may contain errors)
ilriited States atent Discimw et a1.
[451 Apr. 10, 1973  EXPANSION SHELL ASSEMBLY  inventors: Frederick P. Dickow, R.D. No. 6, Auburn, N.Y.; Clifford H. Lambert, 1 12 Bridge St., Naugatuck, Conn.
 Filed: Mar. 24, 1971 21 Appl. No.: 127,701
52 us. ca ..ss/7s  Int. Cl ..Fl6b 13/10  Field of Search ..85/75, 76, 85, 86, 85/79, 74, 67, 73, 88, 82-84  References Cited UNITED STATES PATENTS 2,647,431 8/1953 Lewis ..85/75 3,315,557 4/1967 Dickow v.85/75 1,434,394 11/1922 Matthes... ..85/7S 2,373,585 4/1945 Mancini ..85/75 2,783,673 Lewis 'et a1. ..85/75 FOREIGN PATENTS OR APPLICATIONS 434,885 10/1967 Switzerland ..85/75 Primary ExaminerRamon S. Britts Att0rneyF. P. Keiper 5 7 ABSTRACT Mine roof expansion shell assembly having a one piece shell with annular ring and four expansion fingers with external gripping teeth extending from the ring, and an internal flat wedge engaging surface adjacent the other end, an expanding wedge having a threaded aperture for a mine roof bolt and wedge faces for each of the fingers, the fingers being spaced apart on opposite sides of the shell to form a slot for a wedge retaining U-shaped strap extending over the large diameter end of the wedge with its ends extending through the ring in grooves aligned with the slots, the ends being bent outwardly to engage the underside of the ring, the bent ends being held in place by resiliency of the strap, or the presence of a mine roof bolt threaded into the wedge, and extending through the ring.
4 Claims, 14 Drawing Figures PATENTEB 1 01975 3.726.181
sum 1 BF 2 INVENTORS FREDERICK P. DICHOW.
CLIFFORD WLAMBERT'. v
AT TORNEY PATENTEUAPR 1 @1975 3 ,1 1
INVENTORJ. FREDERICK P. DICKOW' CLIFFORD H. LAMBERT ATTORNEV EXPANSION SHELL ASSEMBLY This invention relates to mine roof support bolts and more particularly to the expansion shell and wedge assembly used therewith.
In mine roof expansion shell assemblies comprising a one piece shell having an annulus or ring from which a plurality of fingers, such as four, extend, which are expanded by a threaded tapered plug or wedge drawn into the shell, the plug and shell have heretofore been held in assembled relation, by being assembled over the extended threaded end of a mine roof bolt, after applying to the bolt a thin nut having shearable threads, the assembly being held on the extended threaded end of the bolt between the threaded wedge and frangible nut. In Dickow U.S. Pat. No. 3,315,557, an attempt was made to secure the assembly by using a strap having its ends hooked into windows inthe tip ends of two opposite fingers, the strap being of U shape and bridging over the wedge to hold it in position in the shell as an assembly without the presence of the mine roof bolt, or the extended threaded end, as in the case of the thin shearable nut. These prior devices have draw backs,
either in competitive manufacture, or in actual use in the field. To avoid separation of the wedge from the shell, the first requires the presence of the bolt end, with a thread longer than would otherwise be necessary, while the second necessitates a casting having apertures in the finger tips which may present difficulties, where castings of malleable iron are employed, and further requires the strap to be'hooked into the aperture in such a way as to minimize interference with the use of the assemblies in the field and the wedging action.
The present invention is directed to an assembly wherein the parts are readily assembled without the necessity of upsetting metal, or distorting the shell and which can be assembled or disassembled in the field, or furnished as assemblies without the bolt, with assurance that the wedge will remain in place in the shell end in the desired assembled relation. More particularly the assembly comprises a wedge holding strap that comprises arms that extend downwardly out of the way between adjacent opposite pairs of expansion shell fingers. The arms extending through the ring, and by lateral projections hooks inplace below the ring. The assembly resists separation of the parts, and when a mine roof bolt is threaded into position in the wedge, the strap ends are physically held spread apart by the body diameter of the bolt, so that no dislocation of the parts can occur except upon the actual expansion of a shell assembly within a bore after which the strap ends may yield if necessary, and if forced to do so by further expansion.
The above and other novel features of the invention will appear more fully hereinafter from the following detailed description when taken in conjunction with the accompanying drawings. It is expressly understood that the drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.
In the drawings, wherein like reference characters indicate like parts:
FIG. 1 is a front elevation of wedge assembly;
FIG. 2 is a side elevation of the assembly of FIG. 1;
an expansion shell and FIG. 3 is a side elevation taken at an angle of 45 degrees from the assembly of FIG. 1;
FIG. 4 is a top plane view of an assembly;
FIG. Sis a view from below;
FIG. 6 is a sectional view taken on the line 6--6 of FIG. 1;
FIG. 7 is a view of an assembly in partially expanded relation against the rock wall of a mine roof bore;
FIG. 8 is a longitudinal sectional view of a shell;
FIG. 9 is an upper end view ofa shell;
FIG. 10 is a lower end view of the shell;
FIG. 11 is an upper end view of a wedge;
FIG. 12 is a side elevation of the wedge;
FIG. 13 is a bottom end view of the wedge; and
FIG. 14 is a sectional view taken on the line 1414 of FIG. 1 1.
In the drawings, there is shown an expansion shell 20, and wedge 22 maintained in assembled relation by a U strap 24 extending over the wedge, with its ends 26 and 28 hooked below the lower end of the shell. The expansion shell, which may be made of a malleable iron casting, comprises four like expansion shell fingers 30, 32, 34 and 36 which project from a ring 38. Each finger comprises an outwardly facing flat section 40 and a plurality of external arcuate gripping teeth 42 of saw tooth configuration.
Internally, each finger has a concave arcuate cylindrical surface 44 formed as a projection of the internal diameter of ring 38, which surface 44 terminates in a flat inclined wedge engaging surface 46 of each finger, which wedge face may have an angle of about 8 from the axis of the shell. Between adjacent fingers are opposite slots 48 and 49, and 50 and 51, having substantially parallel faces 52 and 54, adjacent the ring end 38, which slots widen in the upper region so that the fingers taper slightly in width. The upper end of each finger has an internal bevel 56 of about 45.
The slots 50 and 51 may be a little wider than the slots 48 and 49 adjacent the ring to provide adequate space for the width of the strap 24. The ring is provided on its inner surface with rectangular sectioned grooves 58 and 59 aligned with the slots 50 and 51, such grooves being of a depth corresponding to the thickness of the strap. The internal diameter of the ring 38 is sufficient to loosely and freely clear the threads 60, or the diameter of the support rod 62, which ever is greater, the thread diameter being greater where rolled threads are provided.
The wedge 22 comprises an internal threaded section and an enlarged end opening 72. Externally, it is provided with four wedge faces 74 planar in form and extending at an angle of about 8 from the wedge axis. On two opposite sides between adjacent wedge faces 74, are inclined flat faces 76, and 77 inclined at about.
4 or less, and on the remaining two opposite sides between wedge faces, the wedge has slightly conical surfaces 78.
I With the wedge in position in the end of the shell, 'without expanding the shell, the strap 24 extends over the end of the wedge, with the V bend 80 extending into the end opening 72. The side arms 82 and 84 extend along and in contact with the side faces 76 and 77 of the wedge, and in the slots 50 and 51 between the adjacent fingers of the shell. The ends of the arms 82 and 84 lie in the grooves 58 and 59. The lower ends of the strap each have a right angle outward bend forming hook ends 26 and 28.
It will be readily seen from the foregoing that assembly is effected by placing the strap over wedge side faces 76 and 77, and extending the strap ends downwardly through the ring aperture by sprining the ends together slightly. When in position the strap ends spread into the grooves 58 and S9, and the ends 26 and 28 embrace the lower end of the annulus or ring 38. In effecting assembly, no swaging, deforming or other operation requiring machine operations or brazing or welding is employed, the three parts being readily assembled by hand without tools, if desired.
When an assembly is placed on the threaded end of a mine roof bolt, and is projected into a bore for expansion in hard rock stratta, such initial expansion of the shell fingers prior to insertion can be effected to provide a suitable friction grip of the shell fingers on the bore wall. Thereafter, threading of the bolt into the wedge, with the bolt head bearing on a mine roof support plate, will draw the wedge downwardly and expand the shell into holding relation with the bore. The V bend in the strap may yield as shown in FIG. 7, and if necessary the lateral hook ends 26 and 28, may gradually yield and allow the strap to slip upwardly, as may be necessary, the yield being gradual and not requiring any breaking away of the strap from the shell, or possible injury to the shell. It will also be seen that the strap located between fingers, can not interfere with the smooth action between the wedge surfaces. The bolt end may be cupped as at 182 to swivelly receive and center the V bend 80.
While a single form of the invention has been illustrated and described, it is to be understood that the invention is not limited thereto. As various changes in the construction and arrangement may be made without departing from the spirit ofthe invention, as will be apparent to those skilled in the art, reference will be had to the appended claims for a definition of the limits of the invention.
What is claimed is:
1. A mine roof expansion shell assembly comprising, in combination:
a. a one-piece ring having concentric interior and exterior surfaces of first and second diameters, respectively, and a planar lower surface;
b. four expansion fingers formed integrally with said ring and extending substantially axially thereof from the surface opposite said lower surface in spaced relation to one another, defining therebetween four spaces of predetermined width at intervals, each of said fingers being of substantially the same length and having a free end opposite the juncture with said ring;
. a wedge disposed at least partly within the space enclosed by the free ends of said fingers and having a central, threaded aperture coaxial with said ring, and four wedge faces, each in contact with a respective internal surface of one of said fingers and sloped with respect to the axis of said aperture and ring so that movement of said wedge toward said ring forces said fingers outwardly; and
. a substantially U-shaped strap extending over the end of said wedge farthest from said ring, and through two opposite ones of said four spaces, the width of said strap being less than said predetermined width, and passing through said ring to terrninal end portions which are bent over to extend in closely ad acent, overlying relation to said lower surface and terminate at ends spaced by a distance not greater than said second diameter and biased toward outward movement;
. the space between the opposing portions of said strap extending through said ring being at least as great as the major diameter of said threaded aperture, and the length of said strap from said end portions to the end extending over said wedge being less than the combined length of said fingers and said wedge, whereby said strap serves to retain said wedge within the space enclosed by the free ends of said fingers.
2. The invention according to claim 1 wherein said ring includes a pair of slots spaced by on the internal periphery thereof to receive said end portions of said strap.
3. The invention according to claim 1 wherein said wedge includes a pair of strap clearance faces on opposite sides thereof adjacent which said strap extends, said strap clearance faces being disposed between adjacent ones of said wedge faces, and sloped at a lesser angle with respect to said aperture and ring axis than said wedge faces.
4. The invention according to claim 3 wherein the angle at which said strap clearance faces are disposed withrespect to said axis is approximately one-half the angle at which-said wedge faces are disposed with respect to said axis.