US2575449A - Baler plunger head adjustment - Google Patents

Description

Nov. 20, 1951 QE L m 2,575,449

BALER PLUNGER HEAD ADJUSTMENT Filed March 15, 1948 I IN VENTOR. GEORGE B. H/LL BY RICHARD UZOLLARS .r /1 a ATTOPNEYS Patented Nov. 20, 1951 BALER PLUNGER HEAD ADJUSTMENT George B. Hill and Richard U. Zollars, Ottumwa, Iowa, assignors, to Deere Manufacturing 00., Dubuque, Iowa, a corporation of Iowa Application March 13, 1948, Serial No. 14,648-

17 Claims. (Cl. 100-29) This invention relates to a baling press plunger head construction and more particularly to an improved means for adjusting wearing strips or the like on the plunger head with respect to the bale case. r

The usual baling press has a bale case or chamber that is substantially rectangular in cross section and is relatively long to provide for the reciprocation therein of a generally rectangular plunger head; and it is common practice to provide such plunger head with a plurality of hard wood wearing strips having outer surfaces slidably engaging the wall structure of the bale case. Inasmuch as these wooden strips become worn through use of the baler, provision for adjustment thereof must be made. In assignees earlier patent to McClellan and West 2,428,672, granted October 7, 1947, the provision for adjustment includes longitudinal recesses respectively at the corners of the plunger head, and each of the recesses is on the order of a compound taper to carry a wearing strip correspondingly tapered, so that shifting of a wearing strip longitudinally with respect to the plunger head moves such wearing strip outwardly in two directions. The construction referred to is eminently satisfactory and provides a great improvement over what has gone before. However, this construction is susceptible to improvements and the present invention relates to an improvement therein whereby the mounting of the wearing strips is slightly altered and means is provided for controlling the shifting of the wearing strips with respect to the plunger head.

The principal object of the invention relates generally to the improvement referred to. A further object is to accomplish the desired adjustment by shifting a structural part of the plunger head relative to another part; particularly, shifting a side wall bodily, along with its associated wearing strips with respect to the remainder of the plunger head structure. It is an important object to provide for adjustment of wearing strips independent of adjustment of such structural part. A more specific object resides in the provision of a spreading member cooperable between a portion of the plunger head and a portion of the wearing strips, together with means for moving the spreading member so that the wearing strips may be shifted or adjusted outwardly. A still further object is to provide adjusting means accessible from within the interior of the plunger head, thereby disposin the adjusting means at a readily accessible point clear of the working surfaces of the plunger head.

The foregoing and other important objects and desirable features of the invention will become apparent to those skilled in the art as a complete disclosure of the invention is made in the following detailed description and accompanying sheet of drawings wherein we have shown, by way of example, a preferred form of the invention as adapted to a baling press of one well known type.

In the drawings:

Figure l is a general perspective view showing a plunger head as associated with a bale case and including a plurality of the improved adjusting means;

Figure 2 is a fragmentary sectional view, on an enlarged scale, taken substantially through a plane including the line 2-2 of Figure 1; and

Figure 3 is an exploded view and in perspective, showing a preferred manner of assembling one side wall of the plunger head to the plunger head mounting structure.

The general construction of the plunger head may be similar to that shown in the patent referred to above and may comprise a plurality of sheet steel plates appropriately secured together to provide a box-like structure. This plunger head is adapted to operate in a bale case or chamber which is also of box-like construction. The following specification will describe the invention in connection with a plunger head and a bale case of the type referred to, and for the purposes of brevity and clarity, reference will be had to certain parts as having specified proportions and extending in certain directions with respect to each other. It should be understood, of course, that these terms are descriptive only and are not to be construed as limiting the invention to the specific type of structure set forth. A portion of the bale case is designated by the numeral H) in Figure l and is shown as having a pair of opposed side walls ll and I2 and upper and lower walls l3 and M, a portion of the upper wall being broken away to expose the plunger head, which is designated generally by the numeral 15. The rectangular construction of the bale case I results in the provision of four corners respectively at the junctions of the man (not shown). The lower transverse memher is provided at one end with a flange Z lwhich is rigidly secured, prererably by welding, bolting or riveting, to a plunger head side element or wall 2t. '1. he opposite end or the transverse member 22 is flanged at 26 and is associated With a second plunger nead side element or wall 2?. The connection between the 1118111081522 and the wall 2": will be described in detail below.

The plunger head side wall 25 is provided with an u per mounting portion 28 provided by a pair of angularly related, longitudinally running flanges as and so, this mounting portion being proximate to the corner H of the bale case it). i he nange so or the mounting portion =2uis parallel to the upper wall l3 or the bale case, but the nange 29 is slightly angled with respect to the proximate side wall ll of the bale case. The two flanges 2:1 and 3c provide on the plunger head an external mounting portion at the corner for carrying a. longitudinally extending wearing member preierably in the form of a hard wood strip 3| tapered rrorn one end to the other to correspond to the angle or ta er of the nange 29 with respect to the proximate wall l2 or tne bale case.

The lower part DI the side wall 2:3 is provided with a mounting portion 32 similar to the mounting portion 2a in that it includes a pair of anguiarly related flanges t3 and 34, the flange 3d of which is tapered as is the flange 28 to provide an external mounting portion for carrying a longituuinally extending wearing member in the form of a hard wood strip 35 having generally the same characteristics as the strip 3| and cooperating with the ad oining interior surfaces at the bale case corner l8.

The upper part of the other plunger head side Wall 21 is provided with a mounting portion 38 which includes a pairof angularly related flanges 37 and 38 proximate to the corner Ill of the bale case iii. In the case of this mounting portion, the flanges 37 and 38 are respectively parallel to the bale case walls H and I3 and carry a longitudinally extending wearing member in the form of a hard wood strip 39. This strip, as distinguished from the strips 3| and 35, is rectangular in cross section throughout its length. Thelower part of the side wall 21 is similarlyprovided with a mounting portion 4i) comprising a pair of angularly related flanges 4| and 42 arranged in parallelism respectively with the bale case walls I- and and carrying a longitudinal wearing strip 43 preferably of hard wood as are the other strips. seen that the plunger head carries the four wearing strips 3!, 35, 39 and 43, respectively, at the four corners |7, |8, l9 and N of the bale case, these strips serving to mount the plunger head for reciprocation within the bale case. Inasmuch as continued use of the baling press in which the construction is embodied will result in wear on the wearing strips, it is desirable to provide means for adjusting these strips with respect to the interior surfaces of the bale case along which they slide.

In Figure 3 there is shown the lower portion of the plunger head side wall 21 and the disassembled relationship thereof to the proximate end of the transverse member 22 on which is formed the flange 26. It will be noted that the member 22 includes a second horizontal flange 44 which is at right angles to the flange 2E. The flange M is apertured at 45 and is secured to the flange 4| of the plunger head side wall 2'! by securing means preferably in the form of a pair of car- From the description thus far, it will be riage bolts 46 which pass through slots 41 in the flange 4| and receive nuts 48. The slots 41 are elongated in a transverse direction, or normal to the line of reciprocation of the plunger head, so that the nuts 4e on the bolts 46 may be loosened and the plunger head side wall 2| SniIted bodily inwardly or outwardly with respect to the other plunger head sidewall 25, which-adjustment will of course affect the relationship between the Wearing strips 39 and 43 and the interior surface of-tne bale case wall H at the corners l3 and i9 thereof. It willbe understood, of course, that the upper transverse member 2| is similarly flanged atits corresponding end and is similarly associated with theupper portion of the plunger head side wall 21.

When .the plunger head is assembled, the flange 44 on the transverse member 22 rests on top of or inside the flange 4| of the plunger head side wall 2|; and the vertical flange 26 lies alongside the inner surface of the vertical portion of the wall 21, The flange 26 carries-thereon meansfor efiectingjinward and outward adjustment of the plunger head wall 2? with respect to the main structure of the plunger head. For this purpose, the inner face of the nange 26 is reenforced with av-strip ill of metal preferably secured thereto by welding and provided with a pair of spaced tapped bores '50, each of which receives an adjusting screw 5|. The screws 5| are threaded through the tapped bores 50(and aligned tapped bores in the flange proper) so .thatthe inner ends thereof engage the proximate portion of the vertical part of the wall 21. It will be seen that threading the screws 51 into the bores 56 and against the plunger head wall 21 will effect outward shifting of the wall 21 with respect to the flange 26. If it is desired to shift the wall 21 inwardly, thescrews 5| can be backed off and the wall 21 moved inwardly. Each screw 5| carries a locking nut 52 for securing the screw in adjusted position.

As best shown in Figure 3, the wearing strip 53 is provided .at its upper surface with a pair of recesses $53 which accommodate the heads of the carriage bolts :66. 'It will be understood that the inner surface of zthe upper wearing strip 39 is similarly provided to accommodate the heads of carriage bolts (not shown) which secure the upper portion of the plunger head side wall 27 to the upper transversemember 2|.

In addition to the mounting of the plunger head wall 21 for lateral adjustment with respect to the main plunger head structure, there is provided means for adjusting the wearing strips 3|, 35, 39and43 independently of such adjustment. Figure 2 shows a cross sectional illustration .of an adjusting means which istypical of and similar to the adjusting means forall wearing strips, with exceptions to be pointed out below. The illustration in Figure 2 is of the wearing strip 35 at the corner l8 of the bale case. The mounting portion 32 at the lower part of the plunger head Wall 25 is provided with an interior portion, designated generally-by the numeral 55, preferably in the form of an inwardly directed triangular recessopening outwardly at 56 to a portion of the interior or upper surface of the wearing strip 35. This recess or pocket is preferably formed of a pair of upwardly or inwardly converging wall elements 55a and 55b integral with the flange 4|, the latter being provided with parallel slits and the material between the slits pressed upwardly to form the wall elements and to leave the openingifi. A triangular spreading member 5! is disposed in the recess or pocket formed by the portion 55 and has its base resting on the inner or upper surface of the wearing strip 35, as at 58. One-side of the triangle formed by the block 51 presents a surface 59 which engages a corresponding inclined surface 60 provided by the wall 55a of the pocket or recess 55. The other side of the triangular block is, as at 6|, engaged by an adjusting means or device including a cap screw 62 threaded through a tapped aperture 53 in the wall element 55b. A drilled and tapped reenforcing member 64 is secured, as by welding, to the outer surface of the Wall element 55b to increase the strength of the wall element around the aperture 63. A lock nut 65 is carried by the cap screw 62 for securing the same in adjusted position.

The wallelement 55a is apertured vertically, as at 66, in vertical alignment with an aperture 61 in the triangular block 51. The aperture 51 is preferably in the form of a slot elongated in the direction of the longitudinal extent of the strip 35. The strip 35 has an elongated slot 68 opening into an elongated recess 59 in the outer surface thereof. The recess 89 accommodates the head 70 of securing means includin a bolt 1| which passes through the slot 68, the slot 51 in the triangular block 51, the aperture 66 in the wall element 55aof the pocket 55, and through a tapered washer 12 located outside the pocket 55. The securing means is completed by a washer l3 and nut I4 for Securing the .bolt H in place.

The lower mounting portion 32 of the plunger head side wall 25 is provided with a second adjusting means similar to that just described. This is indicated at 15 in Figure 1. The upper strip 3| is similarly mounted by identical adjusting means, neither of which appears in the drawings. Elongated recesses 16 are visible in the wearing strip 3|; these correspond to the recess 69 in the lower wearing strip 35 and are for the purpose of accommodating the heads of bolts similar to those shown at 1| in Figure 2.

The lower wearing strip 43 at the opposite side wall 21 of the plunger head is mounted or secured to the mounting portion 40 by means of a pair of securing and adjusting means 1! and 18, each of which is substantially identical to that shown and described in connection with Figure 2. However, since adjustment of the wearing strip 43 is only vertically and not fore and aft and vertically as is the case of either of the wearing strips 35 or 3|, there is no need to provide in the wearing strip 43 elongated recesses corresponding to those shown at 69 in Figure 2; nor is there any need for the elongated slot such as at 68 in Figure 2. As shown in Figure 3, one end portion of the wearing strip 43 is apertured at 79 for the purpose of receiving a securing bolt 80 (Figure 1) which is similar to the bolt H in Figure 2. The other end portion of the wearing strip 43 is similarly apertured (notshown) for the purpose of receiving a securing bolt 8| similar to the bolt Bll. The upper wearing strip 35! is mounted on the upper mounting portion 36 by means similar to those just described, only one of such means being visible at 82 in Figure 1. The numeral 83 in Figure 1 indicates recesses for accommodating heads of bolts similar to those shown at 7| in Figure 2.

In the accomplishment of the necessary adjustment to conform the plunger head I5 to the interior working surfaces of the bale case If], the width or lateral dimension of the plunger head may be varied by means of the adjusting screws 5|. The lock nuts 52 are first loosened and then the nuts 48 on the carriage bolts 46 are loosened. Assuming that an adjustment is required to overcome undesirable looseness of the plunger head in the bale case, the adjusting screws 5| are turned in a clockwise direction to move the plunger head side wall 21 outwardly. When the necessary position has been obtained, the nuts 52 and 48 are tightened. Inasmuch as the side wall 25 of the plunger head ordinarily carries a knife (not shown), it may be desirable to adjust this side of the plunger head with respect to the bale case wall l2 so as to maintain the register of the knife with the parts with which it cooperates, all as is well understood by those skilled in the art. It is for this purpose that the mounting portions 30 and 32 include the tapered flanges 29 and 34, respectively. If the nut 14 on the bolt H is loosened (together with a similar change in the securing and adjusting means 15 for the lower strip 35) the strip 35 may be tapped longitudinally in either direction, which will result in moving the outer surface of the strip toward or away from the bale case wall I2 at the corner l3, depending upon the direction in which the strip 35 is tapped. The same is true with respect to the strip 3|.

In the event that it is necessary also to compensate for looseness of the plunger head l5 in a vertical direction with respect to the interior surface of the bale case if), the wearing strips may be shifted vertically with respect to the interior surfaces of the upper and lower bale case walls |3 and M respectively. The manner of accomplishing this adjustment may best be understood by an examination and description of the operation in connection with the illustration in Figure 2. The nut M on the bolt H is first loosened; next the lock nut 65 on the adjusting screw 62 is loosened. The screw 62 may then be turned in a clockwise direction to propel the triangular block 5? longitudinally, which result is accom-' plished because of the engagement between the inclined surfaces 59 and Gil. As the block 51 moves longitudinally it cams the wearing strip 35 outwardly away from the outer surface of the mounting flange 33 on the mounting portion 32. When the necessary position of adjustment has been obtained, the nuts 65 and M are tightened. The same procedure is followed with respect to the adjusting means I5, 11, 18 and 82 and others that are-present in the construction but not illustrated in the drawings.

It will thus be seen from the foregoing description that there has been provided an improved plunger head construction including adjusting means whereby one of the plunger head side walls may be shifted'bodily with respect to the other plunger head side wall and that, in addition, the wearing strips carried by the side walls may be adjusted independently of the side walls. In the case of the securing and adjusting means for either adjustment, the structure is such that all cap screws and nuts are located entirely within the plunger head body out of the way of the working parts of the baler and in locations where they are not likely to become fouled with the material being baled.

We are aware, of course, that there are other types of plunger head constructions to which the present invention may be adapted and we do not intend that the precise details of construction illustrated and described exclude other adaptations of the invention or modifications or vari ations thereof, all of whichmay be accomplished within the spirit and scope of the invention as defined in the appended claims.

We claim:

1. In a baling press plunger head of the type having a hollow interior portion and anexternal portion, and an adjustable wearing stripprcvided with an inner surface that rests on the external portionlof the plunger head and an outer surface that slidably bears against-the wall structure of a bale case in which the plunger jhead reciprocates the improvement residing in means for mounting the wearing strip on the plunger head for adjustment inwardly toward and outwardly away from the aforesaid external portion, comprising: rneans on the plunger head external portion including inwardly directed wall elements providing a recess opening outwardly to the inner surface-ofthe wearing strip and extending into the interior portion of the plunger head, one of said Wall elements including a surface inclined at an acute angle to that portion of the inner surface of the wearing strip to which said recess opens; a spreading member arranged between said inclined surface and the aforesaid. inner surface portion of the wearing strip for movement toward and away from the apex of the angle formed by said surface and said surface portion; and means on the plunger head for propelling said spreading member toward said apex for moving the wearing strip outwardly from the plunger head external portion.

2. The invention defined inclaim 1, further characterized in that: means is provided for releasably securing the wearing strip in any selected position of adjustment, including means for clamping the spreading member between said inclined-surface and said inner surface portion of the wearing strip.

3. The invention defined in claim 2, further characterized in that: the means for propelling the spreading member includes a threaded element adjustably carried by one of the aforesaid wall elements that is opposed to the wall element having the aforesaid inclined surface, said threaded element engaging the spreading memher.

4. In a baling press plunger head of the type having a hollow interior portion and an exterior portion, and an adjustable wearingstrip provided with an inner surface that rests on the external portion of the plunger head and an outer surface that slidably bears against the wall structure of a bale case in which the plunger head reciprocates, the improvement residing in means for mounting the wearing strip on the plunger head for adjustment inwardly toward and outwardly away from the aforesaid external portion, comprising: means providing an opening in the plunger head external portion exposing part of the inner surface of the wearing strip to the plunger head interior portion; and means carried by the plunger head in the interiorportion thereof and extending through said opening into engagement with the wearing strip and effective to move said wearing strip outwardly with respect to the plunger head external portion.

5. In a baling press plunger head of the type having a hollow interior portion and an external portion, and an adjustable wearing strip provided with an inner surface that rests on the external portion of the plunger head and an outer surface that slidably bears against the wall structure of a bale case in which the plunger head reciprocates, the improvement residing in means for mounting the wearing strip .onthe plunger head for adjustment inwardly toward and outwardly away from the aforesaid external'portion, comprising: means providing an opening in the plunger head external portion exposing part of the inner surface of the wearing strip to the plunger head interior .portion; and means including a pair ofcooperative camming elements, one engaging the plunger head interiorportion and. the other engaging the inner surface portion of the wearing strip, said elements being interengageable through said opening and one of said elements being shiftable with respect tothe other; and means carried by the plunger head interior portion for 'movihg'said caminihg elements relativel-y to shift the wearing strip outwardly with respect to the plunger head external portion. I

6; In a baling press plunger head of the type having ,a hollow-interior portion and an external portion, and an-adjustable wearing'strip provided with an inner surfacethat rests on the external portion of the plunger head and an outer surface that -slidably bear-s against the wall structure of a bale case in which the plunger head reciprocates, the imprcvementaresiding in means for mounting the wearing strip on the plunger head for adjustment inwardly toward and outwardly away from the aforesaid external portion, comprising: the plunger headexternal portionhaving an opening exposing part of the inner Surface of the wearing strip to the plunger headlinterior portion; a triangular block having its base resting on the exposed inner surface of the wearing strip audits sides converging through said opening to an apex within the plunger head interior portion; first and second angularly related wall elements fixed to the plunger head interior portion to form a V receiving the converging sides of the block, one side of the block abutting the first wall element and the second wall element including a tapped bore extending ,therethrough and opening to the other side of the block and to the interior portion ofthe; plunger head; and a threaded adjusting member carried by said tapped bore andengaging said ,otherside of the block and accessible from the interior portion of the plunger head for r otation in the tapped bore to move the block tightly against and along the aforesaid first wall element and consequently shifting the block and wearing strip outwardly from the plunger head external portion.

7; The invention defined in claim 6, further characterized in that: the wearing strip, the block and the aforesaid first wall element are provided with aligned apertures; and a securing element passes therethrough for'se'curingthe three in any selected relative positions of adjustmer it.

8. A balin'g pres's plunger head for reciprocatiori in a walled structure forming a bal case, comprising:- an outer structural pc'irtion adjacent the bale case wall structure and having ane'xe ternal surface; an inner portion set back from the outer portion as respects proximity to the bale case wall structure; a wearing strip mounted on the outer structural portion and having an inner surface resting on the external surface of said outer portion, and an outer surface 'fo r'slid= ably bearing on the bale case wall structure; the outer portion having an opening exposing a portion-of-the inner surfaceof the wearing strip; and means movably' carried by the aforesaid set back portion and extending through said opening intoengagement with the wearing strip and effective to move said wearing strip outwardly with respect to the aforesaid outer portion 9. In a baling press having a bale case provided with upper and lower and opposite side Wall portions: a plunger head reciprocable in the bale case, comprising opposite first and second side elements arranged to extend generally in parallelism respectively along and inside the opposite side wall portions of the bale case; means on said side elements respectively longitudinally slidably engageable with said side wall portions; and means extending transversely between said side elements for bodily adjusting one transversely with respect to the other to vary the sliding engagement of said slidable means with the bale case side wall portions.

10. In a baling press having a bale case provided with upper and lower and opposite side wall portions: a plunger head reciprocable in the bale case, comprising opposite first and second side elements arranged to extend generally in parallelism respectively along and inside the opposite side wall portions of the bale case; means on at least the first side element including upper and lower portions respectively adjacent but spaced from the proximate upper and lower inside corners of the bale case; upper and lower wearing members carried respectively by said upper and lower portions of the first side element and respectively longitudinally slidably engaging said corners; mounting structure disposed transversely between said side elements; means connecting the second side element to the mounting structure: and means mounting the first side element on the mounting structure for bodily shifting thereof, together with the wearing members thereon, laterally inwardly or outwardly away from or toward the proximate side wall portion of the bale case.

11. In a baling press having a bale case provided with upper and lower and opposite side wall portions: a plunger head reciprocable in the bale case, comprising opposite first and second side elements arranged to extend generally in parallelism respectively along and inside the opposite side wall portions of the bale case; means on at least the first side element including upper and lower portions respectively adjacent but spaced from the proximate upper and lower inside corners of the bale case; upper and lower wearing members positioned respectively at the upper and lower portions of the first side element for longitudinal sliding engagement respectively with said bale case corners; means mounting the wearing members respectively on the first side element for movement with respect thereto and for adjustment toward or away from the upper and lower bale case wall portions at said corners, respectively; means for securing said members in selected positions of adjustment; and means interconnecting the plunger head side elements for relative adjustment thereof transversely of the bale case independently of adjustment of the wearing members.

12. In a baling press having a bale case provided with upper and lower and opposite side wall portions: a plunger head reciprocable in the bale case, comprising opposite first and second side wall elements arranged to extend genenerally in parallelism respectively along and inside the opposite side wall portions of the bale case: means on said side wall elements longitudinally slidably engageable with certain Wall portions of the bale case; and means interconnecting said side wall elements and constructed and arranged to provide for bodily shifting one side wall element with respect to the other to vary the sliding engagement of certain of said slidable means with a proximate wall portion of the bale case. 7

13. In a baling press having a bale case provided with upper and lower and opposite side wall portions: a plunger head reciprocable in the bale case, comprising a generally hollow structure including opposite, first and second. vertical side walls arranged to extend generally in parallelism along and inside the bale case side wall portions and between the bale case upper and lower wall portions; a transverse member within said hollow structure and extending thereacross from the inside surface of one side wall of the plunger head to the inside surface of the other side wall of the plunger head; means connecting the first side wall of the plunger head to said member; and means connecting the second plunger head side wall to the member including a flange on the member proximate to the side wall, a set of apertures in said second plunger head side wall and a set of cooperable apertures in said fiange, one set of said apertures being in the form of slots extending transversely of the plunger head, and securing means passed through the apertures for adjustably securing said second side wall to the transverse member.

14. The invention defined in claim 13, further characterized in that: the transverse member is provided at a portion thereof proximate to the second side wall with a second flange generally parallel to said second side wall; and means is movably carried by said second flange engageable with the proximate portion of said second side wall for moving said second side wall transversely.

15. In a baling press having a bale case provided with upper and lower and opposite side wall portions: a plunger head reciprocable in the bale case, comprising a generally hollow structure including opposite first and second vertical side walls arranged to extend generally in parallelism along and inside the bale case side wall portions and between the bale case upper and lower wall portions; a transverse member within said hollow structure and extending thereacross from the inside surface of one side wall of the plunger head to the inside surface of the other side wall of the plunger head; means connecting the first side wall of the plunger head to said member; and means connecting the second plunger head side wall to the member including a fiange on said second side wall and extending inwardly normal thereto and adjacent the member, a cooperable flange on the proximate portion of the member, one of said flanges being apertured and the other being slotted transversely of the plunger head, and securing means passed through said apertured and slotted flanges and providing for transverse shifting of said second side wall with respect to the member.

16. The invention defined in claim 15, further characterized in that: the tranverse member is provided with a second flange proximate to its first flange and generally paralleling the inside surface of said second side wall; and means is movably carried by said second flange and engageable with said second side wall for shifting said wall transversely.

1'7. The invention defined in claim 1, further characterized in that: the wearing strip, the spreading member and the wall element having the inclined surface each has an opening therethrough and said openings are alined, and a 11 securing element passes throu h said alined openings and is positioned inwardly ofathe outer surface of the wearing strip.

GEORGE E. HILL. RICHARD U. ZOLLARS.

REFERENCES; CITED Tge following references are of record in the 1316 of this patent:

Number 12 UN ED STATES 'IH'ENTS Na Da e '?""!..T-"T""'. qrundstein an. 4, 1938 Russell V Nov. 14, 1944 McClellan et a1. Oct. 7, 1 94 7

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