US2626023A - Drill post - Google Patents

Description

E. B. LEAF Jan. 20, 1953 DRILL POST Filed Dec. 24, 1948 @HEM N.

Patented Jan. 20, 1953 UNITED. STATES PATENT GFFICE DRILL POST Earl B. Lear, Detroit, Mich., assigner to Chicago Pneumatic Tool Company, New York, N. Y., a corporation of New Jersey Application December 24, 1948, Serial No. 67,120

5 Claims.

This invention relates to drill posts and more particularly to a drill post assembly for use in the drilling of earth formations such as rock, coal and the like.

In the drilling of rock or coal it is frequently necessary to use a post for the support of the drilling apparatus, since the weight of ordinary drilling machines is too great to be carried for any length of time by the operator, especially when drilling holes other than those which are vertically downward.` Various types of drilling posts are used, ranging from a simple post inserted in a hole to posts which are adapted to be anchored in a hole by means of expanding the anchoring end of the post after it is inserted in the hole. In the simple type of post it is important that the post and hole be of good fit if any sort of stability is to be achieved. This type of post is not entirely satisfactory, especially when mounted in other than a horizontal surface, since there is a tendency for the post to be gradually forced from the hole as a result of the forces of reaction which act parallel to the axis of the post. In the usual expansion type of post, While provision is made by means of the expansion feature to counteract the forces of reaction acting parallel to the posts axis, there is not a rigid support, since the Weight of the drilling apparatus and its distance from the Work surface are suicient to develop a moment of force about the base of the post, of such magnitude that it cannot be eilectively counteracted by the post anchoring portion.

To avoid the inherent disadvantages of the drill posts as discussed, the drill post assembly of the present invention operates to effectively counteract all the forces of reaction acting'on the drill post, Which are likely to occur in normal use. The drill post assembly features an anchoring means which has a first portion adapted to effectively resist the forces of reaction which operate parallel to the axis of the post assembly, and a second portion which is adapted to eiectively counteract the forces of reaction transverse thereto.

The drill post assembly of the present invention has been found especially useful in quarry Work where tripod drill mountings were formerly used in drilling vertical or horizontal holes. It is difficult with a tripod mount to drill holes near a vertical surface. However, with the use of this drill post assembly and a long cross-arm mounted thereon, holes may ,be easilyv drilled close to a vertical rock surface.

This drill post assembly is particularly well adapted for channel drilling. Two of these drill post assemblies may be set in the surface of the rock, which is either'vertical or horizontal, at about eight to ten feet apart, and a long channel bar can then be mounted on the drill post assemblies in the manner which is usual in channel drilling. In general, this drill post assembly can be used in most places which are inaccessible to other types of drill mountings.

An object of this invention is to provide a new and novel drill post assembly, which serves as la rigid and stable drill supporting means.

Another object of this invention is to provide a new and novel drill post assembly which can be readily and securely anchored in either a horizontal, vertical or oblique working surface.

A further object of this invention is to provide a drill post assembly which can be used in channel drilling and can also be readily used in places inaccessible to other types of drill mountings.

In order that the invention may be readily understood and carried into eiiect reference is made to the accompanying drawing in which:

Fig. 1 is a perspective View of the drill post assembly.

Fig. 2 is a vertical full-section view of the anchoring means thereof shown in operative position.

Fig. 3 is an enlarged perspective view of a washer used in the drill post assembly of Fig. l,

and

Fig. 4 is a cross-sectional view as seen from line 4-4 of Fig. 2.

The illustrative drill post assembly comprises a post or column member I0 supported by an anchoring means H. The column member sup ports a cross varm i2 Which may be clamped on the column member in any selected position of adjustment by means of bolts I3. The cross arm serves as a support for any suitable drilling apparatus, such as a rock drill drifter (not shown). The column member is most conveniently fashioned from metal tubing, one end being securely fastened to the anchoring means by means of a shrink t which can be reinforced by welding ii desired.

The anchoring means l l comprises a rst portion I4 slidably arranged in part Within a second portion l5, the second portion being located between the first portion and the column member l@ as shown.

The rst portion comprises an expanding collet l5, which is tubular in form, and is `adapted to surround in part a collet expansion means or draw bolt il, and resilient means `in the form of a compression spring le. The expanding collet has a laterally expansible part comprising segments formed by three equispaced longitudinal slots I, extending from the lower extremity to a distance of a little more than one half the length of the collet. The inside surface on each of the three segments at the lower end of the expansible part is arranged to provide a conical surface 2Q, which is tapered to Contact the conical surface portion of the draw bolt, as will later be discussed. Just adjacent the minimum diameter of the conical surface, a shoulder 2| is provided for the abutment of the compressive spring I8. On the outside surface of each of the three segments is arranged a series of parallel grooves or serrations 22. The upper end of the collet has a cylindrical exterior surface 23, which is machined to provide a sliding i'lt with the interior surface of the second portion I5.

The second portion comprises a rectangular yoke-like body 213 having a tubular protrusion at the upper end, and a tubular protrusion 25, frusto-conical in part, at the lower end. The protrusion 25 has an exterior diameter which is adapted to permit the lower end of the column member i to be shrunk t thereon, and a shoulder 2'! about the base to provide a seat for the end of the column member. If desired a weld 28 can be used to reinforce the connection as shown. A hole 29, extends through the protrusion 25 and the yoke-like body 2Q. trusion 25 tapers downwardly to a minimum diameter at the extremity as shown, the minimum diameter being somewhat less than the diameter of a pilot hole |29, in the earth formation in which the drill post assembly is to be anchored. The conical protrusion 25 has a counterbore 3e which extends practically the full length of the protrusion, the diameter being such as to provide a sliding fit with the exterior surface 23 of the collet to prevent lateral movement but permit axial movement between the respective parts. The collet is arranged, during the inoperative position, to engage the counterbore 3l? of the protrusion 2S for a distance of approximately fourfifths the length of said counterbore. At the base of the counterbore 35, a shoulder 3l serves for the abutment of the compressive spring I8. A bore 32 of slightly greater diameter than the diameter of the draw bolt, extends from the shoulder 3l through the yoke-like member 2t. A .boss 33 arranged about the bore 32 and on the inner surface of the yoke-like member has two radial grooves to receive lugs 35 on the bottom of a washer Sil, as shown in Fig. 3.

The draw bolt Il has at one end a frusto-conical head 3S having an exterior surface tapered upwardly at an angle of approximately ten degrees with the axis, or an included angle of twenty degrees, as shown in Fig. 2 of the drawing. The frusto-conical head is adapted to operatively engage the interior conical surface 2G of the expension collet, the contacting surfaces of each being case-hardened to provide good wear. The other end of the draw bolt has a threaded part 3l to receive a draw nut 38 and has a longitudinal groove 39 which is arranged to engage protrusion 4S of Washer 34. A transverse hole is arranged in the bolt near the end of the threaded portion to receive a Cotter pin 4I The washer 34 has an internal diameter slightly larger than the diameter of the draw bolt, and the two lugs 35 on the lower surface fit the grooves of boss 33, while the internal protrusion 13! is arranged to slidably engage the groove 39 of the draw bolt. The bolt I 1 is thus mounted for axial,

The frusto-conical pronon-rotative, movement relative to yoke 24. Upward movement of the draw bolt relative to the yoke causes the bolt to exert a force on the collet, which force may be resolved into a radial component tending to spread the collet segments and an axial component tending to raise the collet against the opposition of spring I 8.

All diameters of the elements are concentric with respect the axis of the drill post assembly, as can be seen from the drawing.

n the assembly of the anchoring means I I, the first portion I4 is slidably arranged within the protrusion 26 of the second portion I5, as heretofore set forth, the compressive spring I8 being arranged within the collet to abut at one end the shoulder 2|, and to abut at the other end shoulder 3| of the tubular protrusion 26. The spring I 8 when positioned in the assembly is compressed to approximately two-thirds its free length and thus serves, to maintain the collet in extended relationship with respect to the conical protrusion 2S, and serves to prevent telescoping action therebetween as the draw nut is first turned. lThe draw bolt il passes within the spring, the conical head 35 being in contact with the tapered surface 2B of the collet and the threaded end extends through the wall of the yoke-like body 24 to receive the washer 365, draw nut 38 and cotter pin 4I. It can be seen that the arrangement of the washer serves to prevent rotation of the draw bolt as the draw nut is turned thereon. The Cotter pin prevents the draw nut from being unintentionally removed from the draw bolt.

To set up the drill post assembly the pilot hole 29 is first drilled in the rock or the earth formation in which it is desired to anchor the assembly, the pilot hole being conveniently formed by means of a hand-held machine or" the sinker type. While the dimensions of the pilot hole vary in accordance with the size of the drill post assembly, a pilot hole approximately 21/2 in diameter and l ft. deep is satisfactory for a drill post assembly having a 31/2" diameter column niember i@ extending to a distance of approximately e ft. above the ground line. The first portion I; and part of the conical tubular portion 26 are inserted in the hole so that contact is made between the edge of the pilot hole opening and the portion 26, as shown in Fig. 2. The draw nut 38 is then turned, causing the draw bolt to be drawn upwardly and expand the collet as a result of the action of the conical head 36 on the conical surface 28 of the collet; up to this stage, the axial component of force transmitted through the collet i5 is insufcient to overcome the compressive force of spring I 8 and relative movement between the collet and second portion 24 is prevented.

After the collet has been expanded a predetermined amount, such being the amount of expansion necessary to cause the serrations 22 to contact the wall of the pilot whole, further turning of the draw nut will cause the serrations t0 bite into the wall of the pilot hole until further expansion of the collet is effectively resisted by the walls of the hole, after which the collet or rst portion i!! in eifect becomes rigidly associated with the draw bolt Il. Further turning of the draw nut meets with increased resistance and causes the second portion I5 to be drawn toward the rst portion I4, with the result that the conical tapered protrusion 2s moves downward and becomes irmiy wedged in the opening of the pilot hole, thereby giving rigid support to the drill post assembly. It can be seen that the spring I8 will be compressed during the latter stages of the anchoring operation, after the turning force on nut 38 has been increased to overcome the increased resistance.

To knock down the drill post assembly it is merely necessary to turn the draw nut in the opposite direction which results in the release of the conical tubular portion 26, which is thus forced from the pilot hole by action of spring I8. Normally, there will be little tendency for the conical head 3B of the draw bolt to become wedged within the conical portion 20 of the collet. However, should such occur a rod can be passed through the column member and hole 29 of the second portion, so that the end of the draw bolt can be tapped slightly and thus break any wedging action at the other end.

What is claimed is:

1. Anchoring means for a drill post adapted for rigid fixation in a pilot hole, comprising a first portion having an expansible collet section, a second portion positioned between the rst portion and the drill post, said second portion having an external conical surface tapering in the direction of the first portion and having a minimum diameter less than the diameter of the pilot hole, said rst portion being slidably arranged in part within the second portion, resilient means maintaining the first portion and the second portion in opposition, a draw bolt extending through the rst and second portions and having a conical portion tapering in the direction of the second portion, and means operable to move the draw bolt in the direction of the second portion thereby forcing the conical surface of the second portion further into the pilot hole after the expansible collet section has been expanded by the conical portion of the draw bolt to fully engage the pilot hole.

2. Anchoring means for a column member for aiixing said column member in a hole, said anchoring means including a first portion having an expansible collet section, a second portion positioned between the first portion and said column member and being aflixed to the latter and having an external surface tapering in the direction of the rst portion said tapered surface being of size to permit partial entry thereof into the anchoring hole, said rst portion arranged in part within the second portion for axial movement relative thereto, yieldable means interposed between the first and second portion resisting axial `movement therebetween, and means operable for expanding the expansible collet section and forcing the second portion toward the first portion after the collet section is expanded a predetermined amount said latter means including a draw bolt having a tapered head whereby the expansible collet section is forced into engagement with the wall of the anchoring hole.

3. Anchoring means for a column member for affixing said column member in a hole, said anchoring means including a first portion having an expansible collet section, a second portion positioned between the first portion and said column member and being affixed to the latter and having an external surface tapering in the direction of the rst portion said tapered surface being of size to permit partial entry thereof into the anchoring hole, said first portion arranged in part within the second portion for axial movement relative thereto, resilient means compressively interposed between the rst portion and the second portion for resisting axial movement therebetween, and means for expanding the collet section a predetermined amount and forcing the second portion toward the rst portion after the collet section is expanded said predetermined amount said latter means including a draw bolt having a tapered head whereby the expansible collet section is forced into engagement with the wall of the anchoring hole.

4. Anchoring means for a column member for affixing said column member in a hole, said anchoring means including a rst portion having an expansible collet section, a second portion positioned between the first portion and said column member and being rigidly aixed to the latter and having an external conical surface tapering in the direction of the first portion said tapered surface being of size to permit partial entry thereof into the anchoring hole, said first portion being slidably arranged in part within said second portion, guiding means preventing rotary movement of the first portion relative the second portion, resilient means maintaining the rst portion and the second portion in opposition, and draw means for expanding the collet section into engagement with the wall -of the anchoring hole including a tapered conical surface tapering in the direction of the second portion, said draw means being further arranged for forcing the second portion toward the rst portion after the collet section is expanded into engagement with the wall of the anchoring hole.

5. An anchoring means as claimed in claim 4 wherein said expansible collet section is provided with a serrated external surface.

EARL B. LEAR.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 725,085 Jacob Apr. 14, 1903 950,492 Pleister Mar. 1, 1910 1,137,443 Ackerman Apr. 27, 1915 1,805,731 Beckwith May 19, 1931 2,442,113 Beijl May 25, 1948 FOREIGN PATENTS Number Country Date 444,623 Great Britain of 1934

Images