US2918840A - Anchor bolt having sleeves with inclined ends - Google Patents

Description

1959 D. P. ROESLER I 2,

ANCHOR BOLT HAVING SLEEVES WITH INCLINED ENDS Filed Feb. 4, 1.955 2 Sheets-Sheet l INVENTOR.

.DA/V/EZ F? P055167? Dec. 29, 1959 D. P. ROESLER ANCHOR BOLT HAVING SLEEVES WITH INCLINED ENDS Filed Feb. 4, 1955 2 Sheets-Sheet 2 INVENTOR. /40 DAN/EL P. EOESLER H NENNY 1h 1 fi w llll z w 1 u w I $06M I/Y A TTOIPA/EYS United States Patent O ANCHOR BOLT HAVING SLEEVES WITH INCLINED ENDS Daniel Pascoe Roesler, Deadwood, S. Dak.

Application February 4, 1955, Serial No. 486,245

2 Claims. (Cl. 85-24) The present invention is an expansible anchor to secure bolts and the like in blind holes, such as holes drilled into rock, concrete or masonry, or in pipe ends or the like.

The principal object of this invention is to grip securely and frietionally lock an anchor member assembled on the shank of a boltagainst the surrounding wall of an opening into which the anchor has been inserted, by manipulation of the bolt from its projecting end.

Other objects are to provide an unyielding wedging grip of the anchor in expanded position, while preventing any interference or jamming between edges of the parts of the anchor in the collapsed position or during the expanding operation; to maintain proper alignment of the portions of the anchor and minimize friction between the parts during expansion or release of the anchor so that the anchor can be readily secured in place or quickly released for removal; to maintain the parts of the anchor in proper relative positions during shipping and handling prior to installation; and to provide a simple, reliable and low cost anchor construction.

In mining operations, as an example, there has long been a need for a simple reusable bolt anchor capable of being inserted with the bolt into a blind hole drilled into rock and manipulated from outside the hole to lock the bolt in place or to release the bolt and anchor when desired. Efforts heretofore made to fill this need have failed for various reasons, in particular because the parts in the released position or during tightening were capable of sticking or jamming in inoperative positions. This problem has been solved in the present invention by constructing and arranging the parts of the anchor so as to prevent any edges of one part being caught in or jammed against another part while the anchor is in released condition or during the engaging or releasing operation.

Other objects and advantages of the invention will be apparent from the following detailed description of preferred embodiments.

In the accompanying drawings:

Fig. 1 is a longitudinal section of a preferred embodiment of the present invention with the parts in exploded or separated relation and with parts in elevation;

Fig. 2 is a similar longitudinal section through the anchor shown in Fig. l tightened into a hole;

Fig. 3 is a longitudinal section taken on the line 33 of Fig. 2 looking in the direction of the arrows;

Fig. 4 is a side elevation of one end wedging section;

Fig. 5 is a cross-section taken on the lines 5-5 of Fig. 4;

Fig. 6 is a side elevation of a bearing plate;

Fig. 7 is a plan view of the plate shown in Fig. 6 looking in the direction of the arrows 7-7 of Fig. 6;

Fig. 8 is a side elevation of an intermediate wedging section;

Fig. 9 is a cross-section taken on the line 9-9 of Fig. 8;

Fig. 10 is a side elevation of the other end wedging section;

, 2,918,840 Patented Dec. 29, 1959 Fig. 11 is a plan view of the same looking in the directionof the arrows 1111 of Fig. 10; I

Fig. 12 is a side elevation of the nut;

Fig. 13 is a bottom: plan view of the same looking in the direction of the arrows 1313 of Fig. 12;

Fig. 14 is a longitudinal section through a modified embodiment of the invention showing the anchor tightened in a hole;

Fig. 15 is a plan .view of the parts in section of the anchor shown in Fig. 14 illustrating a temporary holding coating on the anchor prior to installation;

Fig. 16 is a side elevation of an intermediate section of the anchor shown in Fig. 14 illustrating a further modification; and p i Fig. 17 is a partial longitudinal section showing a u'se of the anchor in ceiling bolting.

The embodiment of'the invention illustrated in Figs. 1 to 13 includes a plurality of tubular wedging sections assembled on a bolt-10 between a flange or shoulder 11 and a nut 12 screwed on to threads 13 extending inwardly from the free end of the bolt. Three such wedging sections are illustrated including two end sections 14 and 15 and an intermediate section 16. It will be understood that if desired additional intermediate sections can be provided. Also assembled on the bolt 10 are bearing plates 17 located between the adjacent end faces of the wedging sections.

Each of the wedging sections 14, 15 and 16 has a cylindrical external surface of a diameter slightly smaller than the internal diameter of the hole in which the anchor is to be secured. The section 14 is formed with an axially extending opening 18 which is oblate in crosss'ection, the minor diameter being only slightly greater than the external diameter of the bolt 10 and the major diameter being sufficiently longer than the minor diameter to accommodate the desired amount of wedging movement of the section. Thus the section 14 may slide or tilt laterally on the bolt 10 in the direction of the major diameter of the opening 18.

The flange, or abutment, 11 is preferably circular in cross-section with a diameter about the same as, or slightly less than, the diameter of the cylindrical external surfaces of the sections 14, 15 and 16, and has a flat annular abutment face 19 preferably arranged perpendicular to the axis of the bolt 10 as illustrated. The flange 11 may consist of a washer 11 Welded to the bolt 10 or may be an integral part of the bolt or otherwise affixed thereto.

The wedge section 14 has one end surface 20 arranged to engage the annular abutment face 19. The end face 20 is approximately perpendicular to the. axis of the section 14 but preferably, as illustrated, forms an acute angle with the axis in the plane passing through the central-portion of the section 14 and the major axis of the opening 18. As illustrated, the opposite end face 21 of the wedge section 14 is likewise flat and is inclined at an angle of about 45 to the central axis of the section 14 in the plane determined by Such central axis and the major axis of the opening 18. The opposite end wedging section 15 is similarly provided with an axial opening 22 substantially the same in cross-section as the opening 18. The section 15 has an. end face 23 arranged substantially perpendicular to the axis of the section and formed with aligned slots 24 preferably lying on and extending in the direction of the minor axis of the opening 22. The opposite end face 25 of the section 15 is also flat and inclined at an angle of about 45 to the central axis of the section 15 in the plane determined by such central axis and the major axis of the opening 22.

The intermediate wedging section 16 is formed with an axial opening 26 which is preferably circular in crosssection with a diameter substantially equal to the length of the major axes of the openings 18 and 22. The section 16 has flat inclined end faces 27 and 28 each inclined at about 45 to the central axis of the section 16 in planes disposed at about 90 to each other.

The nut 12 is formed with a tapped opening fitting the threads 13 on the bolt 10. The under-face 29 of the nut forms an abutment surface engaging the end face 23 of the section 15 and is formed with opposed axially extending lugs 30 adapted to enter the slots 24 on the section 15. The lugs 31}, as illustrated, are preferably narrower than the slots 24 so as not to interfere with tilting of the section 15 with respect to the nut 12.

Each of the bearing plates 17 is formed with opposed flat bearing faces 31 and 32 and is oblate in cross-section when viewed in a direction perpendicular to one of the bearing surfaces as illustrated in Fig. 7. Each bearing plate 17 is formed with a central aperture 33 similar in shape to the periphery of the plate. When viewed from an angle of 45 from the bearing surface 31, or from above as shown in Fig. 6, each bearing plate is circular in cross-section and the internal aperture 33 is likewise circular in cross-section with a cylindrical wall of a diameter only slightly greater than the diameter of the bolt 10. In other words, each bearing plate 17 is the shape of an annular section cut from a hollow cylinder on spaced parallel planes malcing an angle of about 45 with the axis of the cylinder.

In use the section 14 is assembled over the bolt 10 with its end face 20 contacting the abutment face 19 of the flange 11. One of the bearing plates 17 is then slipped over the bolt 10 with its bearing face 32 engaging the inclined end face 21 of the section 14. The intermediate section 16 is then assembled over the bolt 10 with one of its end faces 27 engaging the opposite end face 31 of the bearing plate 17. These three parts may be assembled over the bolt substantially as shown in Fig. 1 and then moved together to bring the end faces 21 and 27 into contact with the opposite sides of the bearing plate 17.

Another bearing plate 17 is assembled over the bolt 10 followed by the wedging section 15 and the nut 12 which is threaded on to the end of the bolt 10 with the lugs 30 enterin the slots 24. The upper bearing plate 17 and the wedging section 15 are rotated 90 counterclockwise from the position shown in Fig. 1 to bring the end faces and 28 into contact with the opposite bearing surfaces 31 and 32 of the upper bearing plate 17.

With the parts assembled on the bolt in this position, and with the nut 12 screwed down far enough to prevent the sections 14, 15 and- 16 rotating about the bolt with respect to each other, the assembly is inserted into the hole into which it is desired to anchor the bolt such as the hole 35 shown diagrammatically in Fig. 2. The bolt 10 is then turned while the anchor assembly is brought into frictional contact with a side wall of the hole, as by pressing it in one direction or the other or by tilting the axis of the bolt 10. Since the sections 14, 15 and 16 are prevented from turning with respect to the section 15 by the lugs 39 entering the slots 24, a slight frictional restraint of one or more of the sections 14, 15 and 16 or of the bearing plates 17 against the wall of the hole 35 is sufiicient to prevent rotation of the entire assembly, so that the turning of the bolt 10 screws the bolt through the nut 12 bringing the flange 11 closer to the nut 12.

As the flange 11 and the nut 12 are caused to approach each other the wedging sections 14, 15 and 16 shift with respect to the axis of the bolt producing an overall radial expansion of the assembly to accommodate the lessening of the distance between the flange 11 and the nut 12. As shown in Figs. 2 and 3 the section 14 is permitted to tip'in the direction of the major axis of its central opening 18 so as to bring its point 36 into contact with the wall of the opening 35. At the same time the intermediate section 16 may tilt in such a way as to bring the point 37 of the end face 27 into engagement with the fit) wall of the hole 35 at a point substantially diametrically opposite the engagement of the point 36. At the same time the point 38 of the upper end face 28 of the inter mediate section 16 is permitted to tilt upwardly as seen in Fig. 2 so as to engage the wall of the hole 35, in the manner shown in Fig. 3, at a point substantially from the engagement of the points 36 and 37 with the wall of the hole 35. Simultaneously the upper end section 15 is permitted to tilt in the direction of the major axis of its central hole 22 so as to bring the point 39 of its end face 25 into engagement with the wall of the hole 35 at a point substantially diametrically opposite the engagement of the point 38, the slots 24 rocking about the lugs 30 as illustrated in'Fig. 3 to permit such tilting. During the tightening and locking the sections 14, 15 and 16 are free to slide bodily into relatively offset positions with their axes substantially parallel to bring their cylindrical side surfaces into full engagement with the wall of the hole 35 at three angularly spaced lines, if the nature of the surface of the hole 35 is such as to urge the sections into that position instead of remaining locked in the tilted condition illustrated in Figs. 2 and 3. When this occurs the axis of the bolt 10 is slightly oifset from the axis of the hole 35, remaining coaxial with the wedging section 15 by reason of the lugs 30 on the nut 12. As soon as the wedging sections have been moved into engagement with the wall of the hole the anchor assembly is gripped and centered in the hole and further rotation of the bolt 10 strongly wedges the sections 14, 15 and 16 against the wall of the hole so as to lock the anchor and bolt in place.

During the movement of the wedging sections 14, 15 and 16 while the anchor is being locked into place in the hole 35, the end faces 21 and 27 of the sections 14- and 16 slide over the bearing surfaces 31 and 32 of the bearing plates 17 disposed therebetween. Sufficient clearance is provided between the central aperture 33 of the bearing plate 17 and the external surface of the bolt 10 to permit the bearing plates 17 to tilt slightly to accommodate, in part, the change in angle of the end faces 21 and 27 due to their tilting but insuflicient to permit the bearing plates 17 to be moved into contact with the wall of the hole 35. The same action occurs at the upper bearing plate 17 between the end faces 25 and 28 of the sections 15 and 16 respectively. Because of the compound tilting of the intermediate section 15 in directions perpendicular to each other the bearing plates 17 cannot fully accommodate the change in angle of the end faces 21 and 27 but remains in position at all times to permit engagement with each of the end faces 21 and 27 at any point about the circumference thereof.

When the sections shift with respect to each other into position wtih their axes parallel and offset so as to engage the wall 35 at three angularly spaced lines the end faces 21, 27, 28 and 25 are pressed into full annular engagement with the opposite sides of the bearing plate 17. In this condition the slightly inclined outer end faces such as the end face 20 of the section 14! may engage the flange 11 only at one side. For use under conditions in which the sections assume axially offset and parallel positions both of the outermost end faces 2%) and 23 may be made perpendicular to the axes of the sections as illustrated in connection with the end face 23. Conversely, for use in conditions in which the sections lock in position in the hole in tilted condition, as shown in Figs. 2 and 3, both of the outermost end faces 20 and 23 may be tilted as illustrated in connection with the end face 29.

Regardless of the relative position assumed by the sections 14, 15 and 16 during tightening and in the locked position the maximum extent of the tilting or offsetting movement of the sections relative to each other is determined by the clearance between the bolt 10 and the major axes of the openings 18 and 22 in the sections 16 and 15 respectively and by the clearance between the bolt and the diameter of the opening 26 in the section 16. Thus the range of diameters of the holes in which an anchor of a particular size can be secured lies be tween the smallest hole into which the anchor assembly can be inserted in its released condition and the maximum diameter in which the anchor can be locked as determined by the maximum expansion permitted by the clearance of the sections from the bolt 10.

The walls of the sections 14 and 15 at the ends of the major axes of the openings 18 and 22 and the wall of the intermediate section 16 are thicker than the maximum lateral movement of the sections with respect to the bearing plate 17 that is permitted by the clearance of the section by the bolt 10. Thus, as illustrated in Figs. 2 and 3, when the anchor is expanded to the maximum extent permitted by the clearance of the sections from the bolt, the end faces 21, 27, 28 and 25 remain, at all times, in position to make complete annular engagement with the opposed faces of the bearing plates 17 so that it is impossible for the outer edge of either of the bearing plates 17 to slip within the inner edge of an abutting end face. Thus, jamming and locking of the sections with respect to each other during tightening or releasing is prevented. In the particular construction illustrated in Figs. 1 to 13 this is elfected by making the bearing plates 17 slightly larger in diameter, when viewed from an axial direction, than the external diameter of the sections 14, 15 and 16. The same effect may be achieved if the external diameter of the bearing plates 17 is reduced to the diameter of the sections 14, 15 and 16 by increasing the critical Wall thickness of the section 16 and at the ends of the major axes of the sections 14 and 15 with respect to the clearance from the bolt 10 proportionately to the reduction in diameter of the bearing plates 17.

Another embodiment of the invention is illustrated in Figs. 14 and 15. In this embodiment end sections 114 and 115 and one or more intermediate sections 116 are formed with cylindrical external surfaces and with central apertures, which may be circular in cross-section, 118, 122 and 126 respectively. The intermediate section 116 is formed with angled end faces 127 and 128 each disposed at approximately 45 to the axis in a common plane passing through the central axis of the section 116, instead of planes rotated with respect to each other as in Figs. 1 to 3. clined bearing face 121 and the section 115 has an inclined end face 125. Bearing plates 117 substantially identical with the bearing plates 17 previously described are interposed between the adjacent inclined faces of the sections 114, 115 and 116. A bolt 110 extends through the sections and is provided with a fixed flange 111 engaging an end face 120 of the section 114 disposed substantially perpendicular of the axis of the section 114. A nut 112 is screwed on to the bolt 110 and is provided with a conical portion 130 fitting into the upper end of the opening 122 in the section 115. The portion 130 is tapered at a relatively small angle as illustrated so that it jams into the end of the section 115 with sufiicient friction to hold the nut 112 from turning with respect to the section 115 when the bolt 110 is screwed up to tighten the anchor in a hole.

In the embodiment illustrated in Figs. 14 and 15 the clearance between the bolt 110 and the axial openings 118, 122 and 126 at any point about the circumference thereof is less than the radial thickness of the walls of the sections 114, 115 and 116 at such point so that the sections cannot move laterally a sufiicient distance to permit the external edge surface of one section to move inside and jam against the internal surface of an adjacent section even if the bearing plates 117 were not provided. With these proportions the bearing plates in either embodiment may be omitted when desired since the adjacent end surfaces of the wedging sections serve Similarly, the section 114 has an in- I 6 to provide a complete annular bearing and prevent iamr'riing during assembly or removal of the anchor. Preferably, however, the bearing plates are also used to in crease the ease of operation.

In use the embodiment illustrated in Figs. 14 and 15 is inserted into a hole such as the hole 135 with the sections in released position and with the nut 112 frictionally engaged in the end of the section 115. A bolt is then rotated While the sections are frictionally engaged with one side or the other of the hole pulling the nut 112 toward the flange 111 and axially compressing the sections. In this embodiment the section 116 is wedged radially outwardly from the bolt 110 and the sections 114 and 115 so as to Wedge the sections against the walls of the hole.

Fig. 16' illustrates a further feature which may be utilized with either embodiment of the invention. The intermediate wedgingsection 216, which is illustrated, is roughened on its exterior surface by stippling, corrugations or the like 236 so as to increase the friction between the surface of the section and the wall of the hole in which it is secured. It will be understood that such roughening may be applied to any or all of the sections in either of the illustrated embodiments.

A further feature of the invention which may be utilized with any particular embodiment of the invention is illustrated in Fig. 15. In this figure the anchor of Fig. 14 is shown in released position with the sections 114, 115 and 116 and the bearing plates 1-17 inaxial alignment and with the nut 112 wedged in the end of the hole in the section 115. In this released position the entire anchor is covered with a thin frangible coating of plastic material, paper or the like to hold the parts in their released, axially aligned position during shipping, handling and installation. The coating may be formed, for example, by dipping or spraying the assembled anchor into liquid plastic material or wrapping it in a thin layer of paper. This coating holds the parts in aligned position until the anchor has been inserted into the hole into which it is to be secured and the bolt 110 rotated. When this is done the frangible coating is ruptured and the sections are wedged apart and locked into the hole as previously described. While the frangible coating is illustrated in the embodiment of Fig. 14 it will be understood, of course, that it may likewise be used in the embodiment shown in Figs. 1 to 13.

In each of the embodiments described it will be ap parent that the bolt and anchor form a unit which can be inserted into a hole and locked into position by rotation of the bolt from outside the hole. The bolt itself may be provided with an eye such as the eye 41 shown in Figs. 1 and 2 to which other members may be secured, or it may be formed in any other suitable way as a connection. During the tightening of the anchor into the hole by rotation of the bolt, it will be clear that as soon as the sections have frictionally engaged the walls further tightening to lock the anchor in place draws the bolt into the hole by screwing it through the nut 12. Thus the present anchor is particularly suitable for use in ceiling bolting and similar uses in mines and the like, as illustrated in Fig. 17, since a bearing plate, washer 42 or the like assembled over the head end of the bolt outside of the hole 35 may be initially pressed against the outer surface of the rock in which the hole is formed and the tightening of the anchor in place serves not only to lock the anchor in the hole but also to pull the head of the bolt tightly against the walls around the open end of the hole. In such uses the head of the bolt 310 may be a nut 341 screwed on to a short thread 343 on the free end of the bolt so as to facilitate the assembly on the bolt of washers or hearing plates 42 to be clamped against the face of the rock in which the hole is formed.

While preferred embodiments of the invention have been described in considerable detail it will be understood that many modifications and rearrangements of the parts may be resorted to without departing from the scope of the invention as defined in the following claims.

What is claimed is:

1. A bolt anchor comprising a bolt having a pair of axially spaced relatively movable abutments, a plurality of tubular sections assembled over said bolt between said abutments, each of said sections having an axial opening therethrough larger than said bolt, the adjacent end faces of said sections being inclined at parallel acute wedging angles to the axes of said sections, a Washer-like bearing plate having parallel sides on said bolt between a pair of adjacent end faces of said sections, said bearing plate having outer radial dimensions at least as large as corresponding radial dimensions of said sections and having an axial opening therethrough larger than said bolt and smaller than the axial openings through said sections providing annular bearing surfaces on the opposite sides of said plate engaging said end faces, and means for moving said abutments toward each other to slide said end faces outwardly along said annular bearing surfaces.

2. A bolt anchor comprising a bolt having a pair of axially spaced relatively movable abutments, a plurality of tubular sections assembled over said bolt between said abutments, each of said sections having an axial opening therethrough larger than said bolt, the adjacent end faces of said sections being inclined at parallel acute wedging angles to the axes of said sections, a washer-like bearing plate on said bolt between a pair of adjacent end faces of said sections, said bearing plate having outer radial dimensions at least as large as corresponding radial dimensions of said sections and having substantially the shape of a portion cut from a hollow cylinder along spaced parallel planes inclined to the axis of said cylinder at substantially the same angle as said adjacent end faces, the axial opening through said cylinder being smaller than the axial openings through said sections and fitting closely about said bolt, said bearing plate having annular bearing surfaces on its opposite sides engageable with said end faces.

References Cited in the file of this patent UNITED STATES PATENTS 79,397 Rogers June 30, 1868 900,462 Aderer Oct. 6, 1908 1,436,763 Healy et al. Nov. 28, 1922 1,982,932 Scribner Dec. 4, 1934 2,051,251 Epstein Aug. 18, 1936 2,125,211 Vogel July 26, 1938 2,365,372 Allen Dec. 19, 1944 2,481,142 Mueller Sept. 6, 1946 2,525,736 Taylor Oct. 10, 1950 FOREIGN PATENTS 4,779 Great Britain Feb. 22, 1897 546,984 Great Britain Aug. 7, 1942

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