US3137352A

US3137352A - Shank protector for earth digging tool

Info

Publication number: US3137352A
Application number: US134520A
Authority: US
Inventors: Gerald A Petersen
Original assignee: PETERSEN ENGINEERING CO Inc
Current assignee: PETERSEN ENGINEERING Co Inc
Priority date: 1961-08-28
Filing date: 1961-08-28
Publication date: 1964-06-16
Anticipated expiration: 1981-06-16

Description

June 1954 G. A. PETERSEN SHANK PROTECTOR FOR EARTH DIGGING 001.

2 Sheets-She 1 Filed Aug. 28, 1961 INVENTOR. GER/4L0 A. PETERSEN AT TOPNEY June 16, 1964 G. A. PETERSEN SHANK PROTECTOR FOR EARTH DIGGING TOOL 2 Sheets-Sheet 2 Filed Aug. 28, 1961 IN VEN TOR.

. GERALD A. PETERSEN A 7'TORNEK United States Patent ()fi ice 1 3,137,352 Patented June 16., 1964 Calif.

Filed Aug. 28, 1961, Ser. No. 134,520 6 Claims. (Cl. 172713) This invention relates to a new and improved protector for the shank plate of an earth digging tool, such as an earth auger for rotary digging of a hole or a trenching or other digging machine.

At the present, various earth digging machines have incorporated therein adjacent the end which performs the digging operation, a heador permanent structure to which is fastened by means of bolts or other means a shank plate which is intended to be relatively permanent. The function of the shank plate is to act in cooperation with one or more earth digging teeth to hold the teeth on the machine in proper position for digging. The replaceable teeth absorb the major part of the wear occasioned by the dig g action, such wear being compensated by reversing the teeth when one surface thereof is worn and eventually by replacing the teeth with new teeth. However, in practice it has been found that exposed surfaces of the shank plate tend to come in contact with the earth being handled, particularly with rock, gravel and sand which abrade certain surfaces of the shank plate. Eventually the shank plate may be worn out and must be replaced.

Accordingly, it is a principal object of the present invention to provide a protector for exposed surfaces of a shank plate for a digging tool, which protector absorbs the abrasive action heretofore mentioned and hence protects the shank against wear, thereby materially prolonging its life particularly in installations where the shank is subject to considerable abrasion.

The protector, which is the subject of the invention, is inexpensive and is a very readily replaceable shield fitting over the surfaces of the shank plate most subject to wear. Preferably,' such protector is formed of sheet metal or the like so that it may be replaced as frequently as required during the life of the tool without the necessity of replacing the shank plate itself. Hence, a feature of the invention is the fact that use of the inexpensive pro tector preserves the life of the relatively expensiveshank plate.

Another feature of the invention is the fact that it may be rapidly and readily installed on existing shank plates and does not require any complicated or expensive machining operation for installation, nor any alteration of the shank plate or teethwhich affects their function.

Still another feature of the invention is the fact that, being of light gauge metal, it may be pressed, bent, cut with shears, or otherwise deformed to fit 'a' variety of shapes of shank plates and. to accommodate variations in shank plates occasioned by wear, repair operations or'malformations. i i

A still further feature of the invention is the fact that it is so constructed that it cooperates with the tooth and the shank for proper retention in place and does'not'require complicated or expensive retaining'means.

A still further feature'of the invention is the factthat its use does not interfere in any way with the operation or efficiency of the earth digging machine, nordoes it detract from the security of the fastening of the tooth to the shank,nor make difficult the intentional removal of the tooth from the shank when the tooth needs replacement. a I

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the several views.

In'the drawings:

FIG. 1 is an exploded perspective view of one form of the invention.

FIG. 2 .is a top plan thereof.

FIG. 3 is a side elevation thereof.

FIG. 4 is a front end elevational view thereof.

tion.

FIG. 6 is a top plan view thereof.

FIG. 7 is a side end elevational view thereof.

FIG. 8 is a bottom plan view thereof.

In the form of the invention shown in FIGS. 1 to 4, inclusive, the tooth 11 consists of a tapered distal portion 12 having reversible cutting edges 13 in a sense that converging top and bottom

distal surfaces

14, 16 are truncated at the front edge. 'Rearwardly at the top and

bottom surfaces

14, 16 are proximal prongs 17 or roots on either side of the tooth separated from each other by a rectangular slot 18 which extends forwardly from the proximal end of the tooth. Each prong 17 has top and

bottom surfaces

19, 21 which are preferably flat and which are preferably parallel to each other butwhich may be slanted if desired. Vertical side walls 22 are formed defining the sides of slot 18 and a resilient insert 23, hereinafter described, presses against such walls 22 to hold tooth 11 in its shank plate26. 1

Tooth 11 is received in shank plate 26 which is fastened by any convenient means to a permanent portion (not shown) ofthe earth digging tool. The shape of shank plate 26 is subject to wide modification, depending upon the use of the tool in which it is installed. Thus, as illustrated herein, shank 26 receives a single tooth 11. However, it willbe understood that in other installations asingle shank plate may receive a plurality of teeth, each tooth being preferably positioned at a proper angle with respect to the other teeth and with respect to the direction of movement of the tool to perform the digging operation in the most effective manner.

In the shank plate'26, illustrated in FIG. 1, there is a i the side walls of the slot. The top or upper member 29 is formed with a top wall 32 on either side of web 28 and the lower member 31 is formed with the bottom wall 33 on either side of web 28. The

spacing'between walls

32, 33 is sufficient to accommodate the thickness of-the prongs 17 of tooth 11.. Extending transversely horizontally through web 28 is a hole (not shown) which receives resilient insert 23 formed of rubber; neoprene, or the like, which is preferably circular in cross-section. The length of insert 23 is substantially greater than the Width of web 28. Thus, in installing the tooth the prongs '17fare inserted in the opening on either sideof web 28xand the. proximal ends of prongs 17 bend insert 23 back and jam the insert between web 28 and the side walls 22, thereby gripping the toothso that it cannot be readily dislodged.

In normal usage of earth digging equipment, dislodgment" of tooth 11 will not occur. By reason of the resilient nature of insert 23, wear,;vibra tion' and the abrasive action of sand, gravel or rocks, in which the tool is digging, and the like, will not ordinarily causeseparation of the tooth from the shank plate. '7 1 When it is necessary to remove tooth 11 as, for'example,

when it is desired to reverse the tooth so that one cutting edge 13, may be substituted for the other, or when it is necessary'for any reason to replace tooth-11, the tooth is dislodged'from the shank plate by driving it forwardly FIG. 5 is an exploded perspective view of a modifica- U by inserting a tool suitable for such purpose behind the proximal end of prongs 17.

The foregoing described construction of tooth 11 and shank plate 26 results in the major portion of the wear of the tool being absorbed by the replaceable tooth 11. However, it is apparent that some of the wear will be absorbed by the shank plate 26 and particularly the upper surface 29 thereof, in that rocks, gravel, and the like, which are cut out of the earth by the tooth, pass over the top of the tooth and hence wear against the leading upper edge of the shank plate. With the passage of time this may necessitate replacement of the shank plate 26. The present invention employs a protector 36 fitting over the wear surface 29 of the shank plate 26, which protector absorbs the wear and hence makes it unnecessary to replace the shank plate.

In the modification shown in FIGS. 1 to 4, inclusive, protector 36 comprises a top portion 37, a bottom portion 33, and an interconnecting central portion 39. The protector 36 is preferably formed of sheet metal and can be deformed by bending, peening, cutting, etc. portion 39 has a Width-substantially equal, but in no case greater than, the width of slot 18. Top portion 37 has a width approximately equal, but in no case greater than the width of upper portion 29 of shank plate 26, and has a length extending back from the leading edge of the shank plate a sufficient distance so that all major Wear is absorbed. T he rearward end of the top portion 37 is formed with a short tab 41 of reduced width which cooperates with a rectangular transverse dimple -2 formed in the top surface 29 of shank plate 26 to receive tab 41. The tab 41 is curved downwardly to fit into and lock within dimple 42 to restrain dislodgment of protector $6. The bottom portion 38 likewise has a width about equal to the width of the bottom portion 33 of shank plate 26 and a length sufficient to absorb the major portion of the wear on the bottom surface of'the shank plate. The tab 43 at the end of the bottom portion 38 is similar to tab 41 and locks into a dimple 44 on the bottom 33 of the shank plate similar to that on the top thereof.

Thus, in use, the protector 36 is applied to shank plate 26 before tooth 11 is installed. Once the tooth 11 is driven into position the protector 36 is locked between Central tending semi-circular extension 61. The top and

bottom surfaces

62, 64 of the shank plate converge rearwardly.

are dislodged by tooth 51 and passed up over shank plate 52.

Protector 66, which is the subject of this invention, is approximately arcuate in end elevation. protector 66 has a length sufiicient to cover the major portion of surface 62 of the shank plate 52 which receives the major wear and converges rearwardly in a triangular shape as viewed in top plan '(see FIG. 6). Surface 67 of protector 66 may be peened or otherwise deformed to form a depressed tab 69 locked into extension 61 of aperture 6G to hold protector 66 in place. The forward edge 71 of protector 66 has a rectangular hole 72 conforming I to socket 69 and generally similar to front end 63. On

either side of protector 66 tabs 72 extend rearwardlyfrom the bottom edge of forward'edge 71 and grip against the bottom surface 64 to hold the protector in place. Projections 58 likewise prevent total dislodgement of the protector. By reason of the deformable nature of the sheet metal of which protector 66 is made and the fact that it may be cut with tin ships as required, protector66 is adaptable to a wide variety of shapes of shank plates 52 and a variety of different configurations wherein the permanent portion of the tool is attached to the shank plate 52. A i

In use, protector 66 is slipped over shank plate 52 and deformed in such manner as toembrace the shank plate as has been explained. The rearward end of the top of the protector is peened to form tab 69 fitting into cut-out 61 to hold the protector in place. Where projections 58 are used on tooth 51 they prevent total dislodgement of the protector in a forward direction. As in the case of the preceding modification, the protector 66 absorhsmost of the wear which would otherwise be received by the the end of slot 18 and the forward end of web 28, so that it cannot be removed as long as the tooth is in place. To further secure the protector in position, the

tabs

41, 43 on the end of top and

bottom portions

37, 38 are peened into the

dimples

42, 44. Because the sheet metal of which the protector 3.6 is constructed is deformable, the protector will accommodate considerable variation in the shape of the shank plate 26. Further, it may be cut with a tin snip or the like if necessary. 7

Since protector 36 is expendable it may be replaced whenever required, the shank plate 26 being protected so that it need not'be replaced.

In the form of the invention shown in FIGS. 5 to 8, inclusive, a different form of tooth 51 is used and the shank plate 52 correspondingly is differently constructed. Thus,

tooth 51 shown in this modification consists of converging distal top and bottom faces 53, 54, truncated at the front edge 56.- Rearwardly of the top and

bottom surfaces

53, 54 is a proximal root 57 which is preferably rectangular in cross-section. In certain forms of teeth of this general type there is on either side of the tooth, a substanti ally rectangular lateral projection 58. Root 57 is received 7 in socket 59 in the shank plate 52. It will be understood that the use of projections 58 is optional.

The shank plate 52 is here illustrated as receiving a v single tooth 51, it being understood that a plurality of teeth may be received. The shank plate 52 is formed with a rectangular socket 59 of a cross-section to receive root 57 with a driving fit and a lengthsufficient to accommodate the length of root 57 with a slight clearance. Rearwardly v of socket 59 the shank plate is cut away in an aperture 69 which preferably has a forwardly exto retain said protector in place so long as said toothis shank plate 52 and can be replaced as frequently as re quired, thereby preserving the shank plate. 7

Although the foregoing. invention has been described in some detail, by way of illustration and example for pur- 1 poses of clarity of understanding, it is understood that certain changes and modifications may be practiced within the spirit of the invention and scope of the. appended claims.

What is claimed is: V i i 1. In combination in an. earth-digging tool," a shank plate formed'with a socket, a tooth formed of a hard, unitary piece of material and having its proximal end shaped to fit into and to be retained within said socket,

and a replaceable protector for said shank plate, said pro;

tector comprising a deformable top portion fittingover the top of said shank plate, said shank plate beingformed I with a dimple in proximity to the rearward edge of said top portion, said protector being indented to fit within and be retained in cooperation with said dimple, said I, I protector having at least one bottom portion and at least one interconnecting portion interconnecting said top por-A 'tion and said bottom portion, said bottom. portion fitting under a part of the bottom of said shank plate, said top" and bottom portions squeezing against the top andbote tom of said shank plate to retain said protector on said 7 shank plate, said interconnecting portion being positioned adjacent the area in which said proximal end enters said socket, said toothand shank plate being formed with parts thereofon opposite sides of said interconnecting portion positioned in said socket.

2. The combination of claim 1, in which said proximal:

At its top 67 end of said tooth is bifurcated and said interconnecting portion fits between the bifurcations of said proximal end. 7 a a 3. In combination in an earth digging tool, a shank plate formed with at least one socket, a tooth formed of a hard, unitary piece of materialand having'a slot in its proximal portion dividing said proximal portion into a pair of roots, at least one of said roots fitting within said socket, retaining means retaining said root in said socket, and a protector formed of thin deformable material having a top portion fitting over a portion of the top of said shank plate, an interconnecting portion fitting between said roots and a bottom portion fitting under a portion of the bottom of said shank.

4. The combination'of claim 3, in which said top of said shank plate is formed with a depression and said top portion of said protector is deformed to fit within said depression.

5. In combination in an earth digging tool, a shank plate formed with a pair of sockets and having a web tom of said shank. v

6. In an earth digging tool, a shank formed with a socket, a tooth formed with a root fitting into i said socket and a replaceable protector of deformable material having a top portion fitting over and protectingfrom wear at least a portion of the top of said shank plate, said protector having bottom tabs fitting-under said shank plate, the top surface of said shank plate being formed with an aperture and said top portion of said protector being deformed to fitwithin said aperture, the portion of said protector interconnecting said top portion and bottom tabs formed with a hole of the samecross-section as said socket and overlying said socket, said tooth formed with an enlarged portion adjacent to said socket to engage said portion of said protector to retain said protectorin place against total dislodgment so long as said tooth is in said position in said shank plate.

References Cited in the file of thispatent UNITED STATES PATENTS 2,702,712

Snyder Feb. 22, 19 55, Launder Jan. 10, 1956 Petersen s Jan. 2ft, 196 1'

Claims

1. IN COMBINATION IN AN EARTH-DIGGING TOOL, A SHANK PLATE FORMED WITH A SOCKET, A TOOTH FORMED OF A HARD, UNITARY PIECE OF MATERIAL AND HAVING ITS PROXIMAL END SHAPED TO FIT INTO AND TO BE RETAINED WITHIN SAID SOCKET, AND A REPLACEABLE PROTECTOR FOR SAID SHANK PLATE, SAID PROTECTOR COMPRISING A DEFORMABLE TOP PORTION FITTING OVER THE TOP OF SAID SHANK PLATE, SAID SHANK PLATE BEING FORMED WITH A DIMPLE IN PROXIMITY TO THE REARWARD EDGE OF SAID TOP PORTION, SAID PROTECTOR BEING INDENTED TO FIT WITHIN AND BE RETAINED IN COOPERATION WITH SAID DIMPLE, SAID PROTECTOR HAVING AT LEAST ONE BOTTOM PORTION AND AT LEAST ONE INTERCONNECTING PORTION INTERCONNECTING SAID TOP PORTION AND SAID BOTTOM PORTION, SAID BOTTOM PORTION FITTING UNDER A PART OF THE BOTTOM OF SAID SHANK PLATE, SAID TOP AND BOTTOM PORTIONS SQUEEZING AGAINST THE TOP AND BOTTOM OF SAID SHANK PLATE TO RETAIN SAID PROTECTOR ON SAID SHANK PLATE, SAID INTERCONNECTING PORTION BEING POSITIONED ADJACENT THE AREA IN WHICH SAID PROXIMAL END ENTERS SAID SOCKET, SAID TOOTH AND SHANK PLATE BEING FORMED WITH PARTS THEREOF ON OPPOSITE SIDES OF SAID INTERCONNECTING PORTION TO RETAIN SAID PROTECTOR IN PLACE SO LONG AS SAID TOOTH IS POSITIONED IN SAID SOCKET.