US2791413A - Cutter bit holder - Google Patents

Description

y 7, 1957 A. o. BRUESTLE ETAL 2,791,413

CUTTER BIT HOLDER 2 Sheets-Sheet 1 Filed July 50, 1954 IN VENTOKS flew/0v Q Bears 72 5:

Ja/IN )E ('42 7'4 IDGE y "062,400: fil E/(n5 A R EYS- y 7, 1957 A. o. BRUES'TLE EI'AL 2,791,413

F CUTTER BIT HOLDER Filed July 30, 1954 Z-Sheets-Sheet 2 ATTORNEYS.

CUTTER BIT HOLDER Armin 0. Bruestle, John R. Cartlidge, and Claude B. Krekeler, Cincinnati, Ohio, assignors to The Cincinnati Mine Machinery Company, Cincinnati, Chic, :1 carparation of Ohio Application July 30, 1954, Serial No. 446,717

1 Claim. (Cl. 262-33) The invention relates to holding means for renewable cutter bits of the so-called rhombodial shape, formed from rolled bar stock by parallel slantwise cuts. Rhomboidal cutter bits are widely used in the cutting chains of mining machines.

It is a primary object of the invention to provide means which will adequately support and hold such bits, withstanding the thrusts of the cutting operation, but permitting ready bit replacement.

It is an object of the invention to provide bit holding means which not only may be employed with bits of the the same kind having dimensional inequalities, but also may be employed with bits of different kinds and shapes, largely interchangeably.

it is an object of the invention to provide bit holding means equally effective with bits having lateral ribs and with bits devoid of lateral ribs; and it is an object of the invention to provide means which will hold a large variety of cutting bits without requiring engagement over top surfaces thereof.

These and other objects of the invention, which will be set forth hereinafter or will be apparent to one skilled in the art upon reading these specifications, are accomplished by that construction and arrangement of parts, of which an exemplary embodiment will now be described. Reference is made to the accompanying drawings wherein:

Figure l is a partial side elevational view of a cutter chain link, its socket means and the bit holding means of this invention, showing a rhomboi-dal bit in the engaged position.

Figure 2 is a perspective end view of a type of rhomboidal bit which may be employed in the practice of the invention.

Figure 3 is a perspective view of an anvil member.

Figure 4 is a perspective View of a clamping member.

Figure 5 is an end elevation of another form of rhomboidal cutter bit which may also be employed in the practice of the invention.

Figure 6 is a partial side elevation of a cutter chain link and bit holding means of this invention arranged so as to be reversible.

Figure 7 is a partial elevational view with portions in section showing primarily a shank arrangement for a reversible assembly, in the use of which it is not necessary to reverse the position of the set screw.

Figure 8 is a partial side elevational view of a cutter chain link, bit and bit holding assembly of reversible type.

Mining machinery, such as that used for undercutting seams of coal, will be well recognized as embodying a driven cutter chain moving about a cutter bar. Alternate links of the chain are provided with extensions perforated transversely of the axis of the links to form sockets. Holding means for the cutter bits are arranged in connection with the sockets. In other types of mining machinery cutter chains move about drums or cutter bits are held in socket members which are mounted on or are integral with other moving members such as drums, driven arms nited States Fatent and the like. The invention will herein be described in connection with socket elements forming parts of conventional chain links; but it will be understood that this does not constitute a necessary limitation on the invention.

The cutter bits, having the rhomboidal shape in side elevation as aforesaid, are characterized by cutting points at either end. The cutter bits themeselves are usually formed of hardened steel, and the cutting points may be reinforced if desired with hard alloy materials such as tungsten carbide. By reason of the oppositely directed cutting points, the bits are reversible in the holders; but when both points have been sufliciently worn to impair cutting efficiency, the bits, being relatively inexpensive, are

discarded. The skilled worker in the art will understand that the socket elements used on cutter chain links are arranged successively at different angularities so that successive cutter bits coact to make a cut of suflicient Width to accommodate the cutter chain and cutter bar assembly.

The cutter bits, as has been indicated, are normally formed from rolled bar or rod stock by cutting this stock transversely along parallel planes slantwise to the axis of the stock. The rolled stock may have varying crosssectional shapes. One form of cutter bit is illustrated in Figures 1 and 2 hereof, being a type of cutter bit shown in our copending application entitled Cutter Bit and Holder, Serial No. 446,716, filed July 30, 1954. This particular cutter bit is characterized by a body portion 1 having lateral ribs 2 and 3 of substantial dimensions. The cutting points 4 and 5 are formed at the intersections of the planes of cut with edge portions of the rod or bar stock. With stock of the shape illustrated in Figure 2, the edge portions of the bit may be made relatively thin while the ribs 2 and 3 strengthen and stabilize the struc ture.

In Figure 1 the chain link is shown as embodying a. socket member 6 having a perforation 7 forming a socket for the reception of the shank of a clamping means. Intermediate the forward and rear ends of the socket member, it is cut away, as at 8, transversely to the perforation 7. This leaves a projection 9 at the front or forward end of the socket member and a projection 10 at the rear end thereof. The latter projection at least has a depth and mass sufiicient to withstand the strains of cutting. The direction of motion of the chain link in cutting, as shown in Figure 1, will be in the direction of the arrow A.

Within the cut-away portion 8 of the socket member and against the projection 9, an anvil member 11 is positioned. While it is possible to made this anvil member integral with the projection 9, when made separately not only can accommodation be arranged for bits of widely different sizes and shapes, but also the anvil member may be renewed if it becomes worn or broken. It may be fastened in place in any suitable way; but it is most con venient to form the anvil member with a forward stud 12 which engages in a perforation 13 in the the projection 9. The terms forward and rear as used herein are based on the direction of cutting movement, as indicated by the arrow A. The anvil member rests against the rear face of the projection 9 and is bottomed on the socket member at the cut-away portion 8.

The anvil member is provided with a recess or depression 14 having a forward planar face 15 lying aslant to the transverse axis of the socket member. The bottom of the recess 14 is related slantwise to the surface 15 to form an angle substantially equal to the obtuse angles of the rhomboidal bit being used. The rearward lower portion of the anvil member 11 projects, as at 16, and has an upper surface 17 in a prolongation of the plane of the bottom of the recess.

There is a holding member having a. head portion 18 Patented May 7, 1957 andashank 19, the latter adapted to be positioned in the socket perforation 7, wherein thereis' also provided '"a fastening means such, for example, as a set screw 20. The rear faceof the clamping member head abuts againstthe forward face ofthe socket member projection 10, as at 2l,'whereby to transfer to the projection the, greater part of the 'horizontal'cutting stresses. The elampingmember is'provided with a forward planar face 22 'whichis parallel to the planar face on the anvil member. Below the planar face 22, the clamping r'nemberis hollowed out, as

at 23, toform a recess which'willaccom'modate the'lower cutting point of the bit'without contacting it, as will be apparent fromiFigure 1. The clampingrnember head also is provided with'two spaced fforward projections 24 and 25 so. shapedand positioned as togengag'e or liealong lateral-faces'of the'bit 1 above its midsection.

Due to the slantwisedifs'po'sitionof the surfaces 15 and 22 'on "the anvil and clampingfmjembersrespectively, an axial movement 'ofthe,clampingmeinbenwith respect to the socket will vary the "spacing betweenthese surfaces. Consequently, it ispossiblert'oposition a bit 1, as shown in Figure Landfengage it between the surfaces 15 and 22 by-adjusting the axial'position'of the clamping member, inspite of suchdimensi'onal variatio'nsein the bit'in the spacing'ofitsfront and rear surfaces as are likely to be encountered in bitsof ordinary manufacture or as between bits of different manufacture but of the same general fro'nt-to rear thickness. The rear surface of the clamping'member shank 19 engagesthe forward facing surface of the perforation in the socket member, as will be evidentfrom Figure L'and isheld .thereagainst by the set screw '20. The fronted'ge of the shank 19'is prefer ably formed aslant, and the axis ofthe set screw 20 is preferably'dispo'sed perpendicular thereto with the fiat nose of the set screw engaging the beveled face and parallel thereto, so that any outward movement of the clamping member is resisted.

The surface '22sustains the-rearward thrust ofthe bit during. the cutting operation, and this thrust is in large part-transferred'to the projection '10'of the socket member, as hereinabove explained. The inward thrust on'the bit is sustained-by-thebottoming of'the lower edge of the biton-theanvil'member, i. ezon the lower surface ofthe recess 14 and on the'contiguous surface of the projection "17. Thisinward thrust is transferred by the anvil memberto'the socket member 6, as will be evident.

It 'shouldbe noted-that'the bottoming of'th'e bit on the anvil member'occurs 'at'that portion of the bottom edge of-the'bit which-is remote from the cutting point atthe same end. Consequently the normal wearing away of thebit-cutting point'will not interfere with this bottoming actionwhen the bitis reversed.

There is little force tending to movethe bit in the opposite direction, iue. outwardly. Such'small forces as are encounteredin this direction, for example forces'due'to centrifugal action, need not be resisted as such. Itis necessary only-to provide against-loss of the bit by outward-movementshould itsengagement with the surfaces 15.and 22 become loosened during'operation. This function. is accomplished-by the clamping member projections 24 and-25=which are so spaced and positioned that the minimunrdistancebetween themsis less than the maximum effective.central widthof'thecutter bit. Where the cutterbithas thesideribs 2 and-3, as shown-in Figure 2, the minimum distance between. theprojeetions. 24.and 25 onthe clamping member will .be less-than the distance between the'outer faces of these jribs. It would be possible to configure the projections 24 -and 25 to engage tightlyabovetheribs 2 and 3', but this is not necessary for reasons which have been outlined above. Consequently, there is shown in Figure 1 an assembly in which thepr'ojection25 lies above but doesnot contact the adjacent rib 3. Hence, dimensional and shape inequalities as between different bits are well accommodated by the structure herein described. The holding means. of this for example, the bit 26"shown in' Figure 5 as having a generally diamond-shaped cross-section. The projections 24 and 25 lie along lateral faces of the bit above its midscction, and the projections will have a minimum spacing less than the maximum widthof the bit at its midsection.

Where the bit is provided with ribs 2 and 3, the upward extent of the -projections 24. and.25 is preferably limited sov as to lie below ahorizontal plane B comprising the-highest'points of-the ribs 2'and 3. Where this is done, the ribs 2 and 3 can act to Iprevent contact of the projections 24 and 25 with the material being cut, and consequent abrasion and wear. The holding means may be projected upwardly, asat-27 behind thebit so as to prolong the surface 22 upwardlyand giveadditional support from the rear.

Lateral tilting of the bit is limited by side portions of the recess 14 in the anvil member and to some extent by the projections 24 and 25 of the clampingmember. vBut inasmuch as a'slight lateral tilting of the bit need not be prevented, it is not necessary that the sidesof. the; recess 14 or the inner faces of the projections 24 and 25 fit the bit exactly. Thus, the holding means of this invention is well adapted to accommodate normal variations in the lateral dimensions and cross-sectional shapes of bits. Where wide variations in cross-sectional shapes are to be encountered, the anvil members 11 of the various chain links'may be replaced by other anvil members having'recesses more appropriately spaced, and the clamping members maylikewise be replaced or exchanged as necessary; but it is a signal advantage of the holding structure herein described that it will not only compensate for dimensional and shape inequalities, regularly encountered in bits of the same general type, but also for normal inequalities -in the 'bitsiofdifferent manufacture.

In certain'types of operation it is desirable to be able to reverse th'ebit and bit holding mechanism in the socket member so that reverse cutting can be done. In the assembly illustrated in Figure 1 the transverse opening 8 across the socket member is nonsymmetrically arranged with'res'pect to the socket opening 7. Reversibility may be attained'in various ways.

A way of attaining reversibility is illustrated in Figure 6 wherein'like parts have been given like index numerals. The opening 8 is symmetrically arranged with respect to the socket forming opening 7, and the general configuration of the anvil and clamping members is as hereinabove described. A filler member 28 is employed behind the clamping member. Theprojection 10 is shown as having a perforation-29 similar to the perforation 13 in the projection 9. The filler member-28has a lug 30 adapted to enter the perforation 29. Thus it will be seen that the anvil member 11 and the filler member 28 are interchangeablein position as respects the projections 9 and 10 of the socket member. If reverse cutting is desired, the parts 11, 1, -18-and 28 are simply reversed in their respective positions. And the set screw 20 is removed and reinserted in an opposite threaded opening 31 in the socket member.

It is highly desirable that the rear edge 32 of the clamping member shank lie against the front or rear edge of the socket forming perforation 7, to be held thereagainst by the set screw 20. In practice the front edge 33 of the shank may be tapered toward the head portion and the threaded opening, for the set screw so tilted with respect to the horizontal, axis of the socket member that the set screw'axis will lie perpendicular to the edge 33.

If desired the rear portion of the clamping member head 18may be provided with a lug 34 which engages in a notch or groove 35 in the filler member 28. This will assist in preventing any tilting movement of the clamping member 18.

Where it is desired to attain reversibility in cutting Withontcha'n'ging the position of the set screw 20, the shank 36 of'the clamping member may be configured as shown in Figure 7. Here the shank has the same dimensions at both ends, but intermediate these ends and over the area which would be engaged by the set screw 20, the shank is provided with slanting surfaces 37 and 38. The full sized portions of the shank 36 will permit either of its edges to abut against the surface 39 of the socket member opening, opposite the set screw 20.

Yet another way of attaining reversibility is illustrated in Figure 8. Here the opening 8 is again symmetrically arranged with respect to the socket opening 7, but there are no separate anvil and filler pieces. Instead, the opening 15a and the bottoming surfaces 17a are formed directly in the socket member projection 9a, and exactly similar configurations are formed as at 15b and 17b directly in the projection a. The rear portion of the clamping member head 18 is preferably provided with a lug 40 so proportioned as to enter the recess b.

It will be seen from Figure 8 that the parts are directly and simply reversible, all that is required being the removal, reversal and reinsertion of the clamping member 18 together with a repositioning of the bit 1 and the set screw 20. Other advantages of the construction are the elimination of separate parts and the provision of greater thrust-resisting thickness in the projections 9a and 10a for a given length of socket member. A disadvantage lies in the lack of removability of parts if the configured openings 15a, 17a, 15b and 17b change by reason of wear or breakage.

Modifications may be made in the invention without departing from the spirit of it. Having thus described the invention in an exemplary embodiment, what is claimed as new and desired to be secured by Letters Patent is:

In a cutting assembly, a socket member, said member having a shank-receiving perforation transverse its axis and being cut away outwardly transverse said perforation so as to leave forward and rear upstanding projections, the cut away portion having a greater length in the direction of the axis than the width of said perforation, an anvil member positioned against the forward one of said projections and bottomed on said socket member,

said anvil member having a forward stud adapted to en ter a longitudinal perforation in said forward projection, whereby to prevent axial movement of said anvil member, said anvil member being detachable from the socket member for renewal purposes, and a clamping member having a head and a shank, said shank adapted to enter said perforation and be fastened therein, said head having a surface backed by the rear one of said projections whereby to transfer cutting strains to it, said anvil member having a recess to receive and bottom a lower portion of a cutting bit, said recess having a slantwise disposed rear uniplanar face, said clamping member having a forward- 1y disposed slantwise uniplanar face parallel to the planar face of said anvil member, said anvil member having a rearward projection shaped to form a bottoming element for a rhomboidal bit, the front and rear faces of which are engaged between the aforesaid parallel surfaces, and said clamping member having spaced forward projections adapted to lie along lateral faces of a rhomboidal bit above the midsection thereof, said projections being spaced at a distance less than the maximum lateral width of a bit to be engaged, said clamping member being adjustable in the direction of the axis of its shank whereby to vary the interspacing of said parallel planar surfaces of the anvil member and the clamping member, the recess in the said anvil member having side portions acting to limit lateral tilting of the bit by engagement with lateral surfaces thereof below the bit midsection, said clamping member being hollowed to accommodate without con tact the lower cutting point of a rhomboidal bit, said clamping member being prolonged upwardly in a position behind the cutting bit so as to extend its planar surface and provide additional support for the bit against horizontal cutting stresses, in combination with a rhomboidal bit of generally diamond-shaped cross-section, said rhomboidal bit having lateral ribs at its midsection projecting outwardly, the said projections of said clamping member adapted to lie above the said lateral ribs, with the outward extent of the said projections in the direction of the axis of said shank limited by a plane normal to the said axis which includes the outermost extent of the said ribs.

References Cited in the file of this patent UNITED STATES PATENTS 1,897,331 Rassieur et al. Feb. 14, 1933 2,039,747 Stenger et al May 5, 1936 2,255,856 Morrow Sept. 16, 1941 2,348,061 Daberstein May 2, 1944 2,415,107 Morrow Feb. 4, 1947 2,434,356 Bowman Jan. 13, 1948 2,613,069 Bruestle Oct. 7, 1952 2,644,680 Simmons July 7, 1953

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