US2805496A - Extensible trencher tooth - Google Patents

Description

Sept. 10, 1957 R. L. JORDAN 2,805,495

EXTENSIBLE TRENCHER TOOTH Filed May 27, 1954 2 sheets sheet 1 INVENTOR. ROBERT L. JORDAN %ww A /M/ Sept. 10, 1957 R. L. JORDAN 2,805,496

EXTENSIBLE TRENCHER TOOTH Filed May 27, 1954 2 Sheets-$heet 2 iii INVENTOR. ROBERT L. JORDAN A 7' TORNEY United St EXTENSIBLE TRENCHER TOOTH Robert L. Jordan, Sacramento, Caiif.

Application May 27, 1954, Serial No. 432,680

1 Claim. (Cl. 37-442) My invention relates to improvements in teeth for trenching and digging machines and more particularly to teeth having cutting blades which may be extended to compensate for wear.

In the operation of trenching and digging machines one of the major causes of inoperative periods or unproductive down time is the necessity for changing the blades of the teeth on the buckets. Owing to the abrasive action of the dirt, rocks and soil being dug, the blades quickly become worn to a short length, thereby reducing the machines cutting efficiency or rendering it inoperative. Attempts have been made to correct this, the attempts having usually been directed toward reducing blade wear by making the blades of very high quality, carefully heat treated steel and alloys. While this to some extent has overcome the difiiculty of blade wear, yet the cost of these high grade blades becomes a substantial expense item and even with the very best blades, wear takes place at a considerable rate and replacement becomes necessary, with its attendant down time. The replacement of old worn blades by new blades consumes a substantial amount of time during which fixed costs and labor costs continue. While considerable effort has been exerted in this field to reduce blade replacement time, for example, by the use of special adapters and pockets and other types of blade holders, and which have to some extent reduced replacement time, yet so far as is known all of these special and relatively costly blade holders and adapters require the use of the expensive varieties of blades and the kinds of blades which must be discarded when worn. None of them, as a matter of common knowledge in the art, utilizes a relatively inexpensive blade and a blade which quickly can be extended outwardly to new blade position and thus outlast the expensive types of blades.

It is therefore an object of my invention to provide an extensible trencher tooth which, as the blade becomes worn, effects by means of a very simple and rapid operation, the positioning of the blade to a location such as would be occupied by a new blade.

It is another object of my invention to provide an extensible trencher tooth which may quickly and easily be installed and removed from trencher buckets of the kinds commonly used.

It is still another object of my invention to provide an extensible trencher tooth which is economical to manufacture and which may be installed and the blade extended with the use of very simple hand tools and by unskilled labor.

It is yet another object of my invention to provide an extensible trencher tooth which provides a positive lock on the blade and which thus prevents the blade being forced inwardly by the ground.

It is a still further object of my invention to provide an extensible trencher tooth wherein the blade employed does not need to be of the highest quality steel or alloy and heat treated in an expensive manner.

Other objects, together with the foregoing, are at- Patented Sept. 10, 1957 tained in the embodiment of the invention described below and illustrated in the accompanying drawings, in which:

Figure 1 is a side elevation in semi-diagrammatic form of a trencher wheel having buckets thereon and showing a number of the trencher teeth installed on the buckets. A portion of the figure is broken away to reduce the extent of the figure.

Figure 2 is a perspective of the extensible trencher tooth.

Figure 3 is a section along a substantially median vertical, longitudinal plane of the tooth shown in Figure 2 in installed position on a bucket edge.

Figure 4 is a perspective of the blade clamping member.

Figure 5 is a perspective similar to the view shown in Figure 2 but having a portion of the upper part of the body broken away to show a worn blade in recently extended and locked position and having a portion of the blade broken away to show a portion of the clamping member in blade clamping position.

Trenching machines or ditching machines or trenchers, as they are variously known, are customarily either of the ladder type or of the wheel type. In Figure 1 a portion of a trencher of the wheel type is shown, the trencher tooth of my invention, however, being equally usable on the ladder type, the trencher machine (not shown) having projecting from the rear end thereof a supporting arm 6 having mounted thereon a rotatable power-driven wheel 7. Mounted around the perimeter of the wheel 7 is a plurality of buckets 8 secured to the wheel perimeter, as by fastenings 9. The buckets commonly in use assume a variety of forms but the form illustrated is typical and comprises a back wall llienlarged at its inner edge to form a mounting bracket 11 and projecting radially from the perimeter of the wheel, with the wall it} being curved forwardly in the direction of rotation of the wheel, as shown by the arrow 12, to form a bottom wall 13terminating at its leading extremity in a leading edge 14 whichfrequently is tapered forwardly and inwardly to a point 15. Extending from both sides of the back' wall 16 to the wheel perimeter are side walls 16 and which with the other walls of the bucket and the wheel perimeter form a bucket-like cavity or pocket into which loosened earth 17 spills as the excavating bucket revolves, the buckets being emptied near the top of their travel into a suitable chute or conveyor. As the wheel 7 rotates, the trenching machine proceeds forwardly in a direction indicated by the arrow 18, the combined movement causing each succeeding bucket to scoop up an additional amount of earth, as indicated by the numeral 21.

Mounted around the edge of each of the trencher buckets is a plurality of trencher teeth 22, the teeth being distributed not only along the back wall 10 of the bucket but along the side walls 16 as well. The teeth disposed on the side walls 16 define the trench width by cutting the soil on the sides of the trench, the side teeth moving in a substantially vertical plane. In operation, it is customary for the blade of the trencher tooth to extend forwardly in the direction of motion of the blade and to be inclined slightly outwardly, as most clearly appears in Figure 1. The outermost point or tip of the blade is customarily adjusted so as to protrude slightly beyond the plane of the outer side of the tooth for in this position the blade scrapes a channel in the earth in which the tooth holder can travel unobstructed, and as is illustrated by the blade in contact with the earth in Figure 1. The extensible trencher tooth 22 of my invention comprises a body 23 including a lower portion 24 and an upper portion 26 or check or cap. Projecting rearwardly from the lower portion 24 is a shank 27 having a top surface 23 suitably con-formed for close abutment with the outer side of the bucket wall. Piercing the shank is a pair of apertures, such as 29 and 30, to receive through bolts 31 and 32 respectively for fastening the shank to thebucket wall. Projecting rearwardly from the upper portion or cheek of the body is a lip 33, having an aperture 34 therein to receive the'fastening 31. The portion of'the body between the lip and the shank is tapered, as 'at 36,to receive in tight engagement the tapered portion 14 of the bucket edge, and thereby stiffening the mounting of the body on the bucket edge. At the end of the body away from the shank is a face 37 substantially normal to the general plane of the shank and extending from the lower side of the body upwardly to the upper forward end of the cheek 26.

As appears most clearly in Figure 3, the body 23 has formed therein a generally elongated chamber 41 inclined from an opening 42 in the front face 37 rearwardly and upwardly, as appears most clearly in Figure 3, and terminating, in a rearwall 43.; The opposite edges 44 of the chamber are bounded by the edge walls of the cap 26 or cheek portion of the body and serve to confine a blade 46 disposed within the chamber against lateral or transverse motion, the lateral dimension or width of the blade being slightly less than the width of the chamber. The blade 46 is of a springy or resilient material, preferably steel, and in its new'or' original length extends from its innermost end 45 in abutment with the chamber end 43 outwardly through the opening 42 and extending still further outwardly to terminate in a blade tip 47, the tip 47 being at a location preferably below the general plane of the lower side 48 of the body. This blade position, as may be seen by reference to Figure 1, will tend to undercut the earth so that the earth does not impinge directly upon the face 37 or body 23 of the trencher tooth and will thus avoid the wear on the tooth which otherwise would obtain.

The lower side 51 of the chamber, as appears in Figure 3, is defined by a generally planar surface 52 extending from the lower side 53 of the opening 42 to the rear abutment wall 43 of the chamber. The upper side 56 of the chamber is generally serrated in cross-section and extends inwardly from the upper side 61'of the opening 42 and for a short portion 62 of its length is substantially parallel with the planar portion 52 of the lower side of the chamber. At the innermost end of the parallel portion 62, however, the chamber inclines upwardly to define a sloping portion 66 or tread surface and then in serrated or stepped fashion projects inwardly and toward the lower side of the chamber to form a riser surface 67 'or abutment wall. As the riser surface 67 approaches the planar portion 52 at a distance somewhat in excess of the distance separating the parallel planar portions 62 and 52, the riser surface again inclines upwardly and rearwardly in a direction generally parallel to the tread surface 66 and forming a tread surface 68 followed by an inwardly' jutting riser surface 69. This latter step, in turn, is followed by another and similar tread surface 71 and a corresponding riser surface 72. Following the riser 72, a still further tread surface 73 terminates in an innermost riser surface and which is congruent with the rear abutment wall 43.

Transversely disposed within the lower portion 24 of the body 23 is a cavity 81 substantially right circular cylindrical in section and extending from one side of the body to the other. The upper portion of the cavity opens into the chamber 41.' Disp'osed'within the transverse cavity 81is a'clamping member, generally designated 84, and most clearly appearing in Figures 4 and 5. The clamping member 84 comprises a pair of oppositely disposed journals 86 and 87, or flanges, substantially right circular cylindrical in section and of a size slightly less in diameter than the cavity 81. Each of the journals 86 and 87 has formed in the outermost face thereof a socket 88'to accommodate an appropriate size and kind of socket wrench while a square or hexagonal or other head could be used'in place of the. socket, the

Socket provides a surface free of undesirable projections. The central portion 89 of the clamping member, disposed between the inner faces 91 and 92 of the journals is formed so thatone portion 93 of its outer periphery is flat, the flat surface 93 coinciding with or being co-planar with, in one position of the clamping member, the plane 52 of the chambers lower side 51;

The remaining portion ,94 of the outer surface of the central portion 89 is cam shaped in section, as most clearly appears in Figure 3, and the surface of the cam is roughened, such as by'knur1ing 96.' The cam surface is so shaped that as the clamping member is rotated clockwise, as appears in Figure 3, the uppermost transverse line of contact between the knurled cam surface and the underneath side of the blade moves upwardly, the amount of upward motion corresponding to a predetermined amount of rotation of the clamping member. The greater is the amount of clockwise rotation, the more the upward deflection of the blade. It is to be noted that when the blade is disposed in the chamber, the inner faces 91and 92 of the flanges straddle the blade and thusfthe clamping member is prevented from. lateral translation. If necessary to remove the clamping member 84, however, removal of the'blade allows the member 84'to be withdrawn. g When a new blade is to be installed, the blades innermost or root portion 45 is pushed inwardly through'the opening 42 and into abutment with the innermost end 43 of the chamber, the outermost tip 47 of the blade then being in the position approximately as shown in Figure 3. ing member 84 is-in its normal or inactive position,in which attitude the fiat surface 93 is substantially coplanar with the lower or underneath surface of the blade,

the blade sliding over the flat surface 93. With the-blade in the position shown in Figure 3, a socket wrench is inserted in the socket 88 and turned clockwise so that a slight ridge 95 at the intersection of the flat face 93 and the knurled surface 94 bears against the bottom side of the blade. As rotation is continued the knurled surface of the-cam face deforms the adjacent portion of the blade more and more upwardly until the blade assumes a somewhat bowed shape, as appears in Figure 3. Concurrently, the end of the blade is also urged inwardly with a very considerable force against the abutment wall 43 since as the cam face is turned clockwise the knurled portionof the cam face bites into the blade and forces portion 66 of the upper side of the chamber. Also, fadjacentthe lower tip of the riser surface 72 a tight engagement is obtained between the upper portion ofthe blade and the tip. Further rotation of the cam face causes even greater distortion of the blade and eventually forces the upper surface of the blade to come into engagement with the lower tips of the riser surfaces 67 and 69. In this extreme position the frictional engage-' ment between blade and chamber walls offers great resistance to the blades translation either toward the left or toward the right. The frictional resistance to inward translation augments or supplements the positive bar to movement provided by the end wall 43. In this situation the blade is held very tightly and rigidly within the body of the trencher tooth, and the blade is not only prevented from translating in either direction but also from traversing the chamber laterally. j

As the blade becomes worn and the tip-0f the blade approaches a' position at or about the plane of the lower surface 48 of the body, the clamping member, by a socket wrench, maybe turned counter-clockwise until the fl at While the blade is being inserted, the clampsurface 93 is again in contact with the lower portion of the blade, the resilience of the blade having returned the blade to its normal planar attitude and permitting the blade to he slid along the elongated chamber in an outward direction and into a location such that the innermost end of the blade is adjacent the riser face 72. At this juncture, the clamping member 84 may again be rotated counter-clockwise and thus deforming the blade upwardly and wing it toward the right so that the innermost end 45 of the blade comes into tight abutment with the riser surface 72, and with the upper innermost portion of the blade bearing tightly against the tread surface 71. Thus as the blade becomes worn, the clamping member may be loosened, the blade pulled outwardly to a position below the next outermost step, and the blade cammed into its next position. This operation is repeated each time the blade is to be extended. Figure 5 shows the blade in one of these intermediate positions and illustrates the manner in which the innermost end of the blade is deformed upwardly and inwardly against the riser surface 69 and is also in tight engagement on its upper surface with the tread surface 68. Any convenient number of serrations may be used and when the blade has become worn when in its outermost position, that is, in abutment with the wall 67, the blade is discarded and a new blade inserted. As will be seen, the extensible trencher tooth of my invention permits approximately one-third of the original length of the blade to be worn away before replacement is necessary and the replacement operation itself is quickly performed, with simple, readily available hand-tools and by unskilled labor.

It has been found that by inclining the riser surfaces 67, 69, 72 and 73 in such a direction that full contact between the respective riser surfaces and the root end 45 of the blade is effected when the blade is in its most deformed position, a greater blade rigidity is obtained.

As appears most clearly in Figure 3, the riser surfaces are not all exactly parallel but are at an angle with respect to each other and all of them face generally toward the opening 42 in the outer face of the body.

What is claimed is:

An extensible trencher tooth comprising a body having formed therein an elongated chamber open at one end of said body, said chamber being bounded by a substantially planar first side and opposite said first side a second side formed with a plurality of steps therein, each of said steps including a riser surface facing toward said open end of said chamber, an elongated blade in said chamber, and rotatable means for urging the inner end of said blade in a direction away from said planar first side and toward said second side and into abutment with a predetermined one of said riser surfaces, said rotatable means including a pair of members adjacent each edge of said blade whereby said rotatable means is constrained against translation when said blade is in said chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,265,359 Moore May 7, 1918 1,333,852 Kittredge Mar. 16, 1920 1,834,391 Edmunds Dec. 1, 1931 2,223,831 Luers Dec. 3, 1940 2,250,904 Coflman July 29, 1941 2,339,128 Younie Jan. 11, 1944 FOREIGN PATENTS 12,117 Norway Aug. 10, 1903

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