US3357117A - Resilient retaining means for digging implement blades - Google Patents

Description

Dec. 12, 1967 A. PETERSEN 3,357,117

RESILIENT RETAINING MEANS FOR DIGGING IMPLEMENT BLADES Filed Dec. 14, 1964 5 Sheets-Sheet 1 I37 A 7' TORNE) Dec. 12, 1967 G. A. PETERSEN 3,357,117

RESILIENT RETAINING MEANS FOR DIGGINC' IMPLEMENT BLADES Filed Dec. 14, 1964 5 Sheets-Sheet 2 llof I 36a 27a (IZQ 50 X I INVENTOR. ,fl A 17 GERALD A. PETERSEN A TTORNE) Dec. 12, 1967 A. PETERSEN 3,357,117

RESILIENT RETAINING MEANS FOR DIGGING IMPLEMENT BLADES Filed Dec. 14, 1964 5 Sheets-Sheet 3 f zsb 36 b WZOb 56\ A 52b l 2 b [2b (\NW INVENTOR. I 3/ GERALD PETERSEN 37b 28b BY H ATTORNEY Dec. 12, 1967 G. A. PETERSEN 3,357,117

RESILIBNT RETAINING MEANS FOR DIGGING IMPLEMENT BLADES Filed Dec. 14, 1964 5 Sheets-Sheet 4 \526 BYGER/ILD ,4. PETE/65y 42 c 37: 28:: a

' A r TOR/VEV Dec. 12, 1967 A. PETERSEN 3,357,117

ENT BLALLS RESILIENT RETAINING MEANS FOR DIGGING IMPLEM 5 Sheets-Sheet 5 Filed Dec. 14, 1964 E INVENTOR. GERALD A. PETERSEN United States Patent Ofiice 3,357,117 RESILIENT RETAINING MEANS FOR DIGGING IMPLEMENT BLADES Gerald A. Petersen, Sunnyvale, Calif., assignor of to Anita E. Petersen, Saratoga, Calif. Filed Dec. 14, 1964, Ser. No. 418,073 12 Claims. (Q1. 37-142) This invention relates to a new and improved resilient retaining means for digging implement blades. The resilient retainer is compressed between the blade and its holder and provides frictional resistance to unintentional disengagement of the parts.

The present invention has particular application the removable blades of earth digging machines, such as graders, dippers, back hoes, harrows, scarifies, cable plows, and similar equipment wherein the blade is subjected to heavier stresses and generally is larger than the removable teeth to which the resilient retainer principle has heretofore been applied. In heavy equipment of the type to which this invention is most applicable, a tooth formed with a hollow or recess is driven into or over a shank attached to a permanent part of the machine. The blade frictionally engages the shank, or is welded thereto, or various keys are used to hold the parts in place, or one of the mating parts is deformed as by swedging, dimpling, staking, or the like. The forces applied to the blade in use tend either to drive the blade so firmly into engagement with the shank as to make it difficult, if not impossible, to separate when replacement of the blade is required, or, on the other hand, tend to separate the two parts by reason of the extreme and unpredictable stresses to which the blade is subjected. In accordance with the present invention, a resilient retainer is compressed between the blade and the shank, with an extended area of surface contact between the insert and the two parts which it engages, so as to frictio-nally hold the blade on its shank against unintentional dislodgment despite extreme stresses tending to separate the parts. On the other hand, since the resiliency of the insert is an important feature of the invention, the forces tending to prevent dislodgment of the two members when it is necessary to replace the blade are largely overcome and it is merely necessary to apply suificient force in the proper direction to overcome the frictional resistance.

Accordingly, it is a principal purpose of the present invention to provide means for retaining a blade on a permanent portion of a machine in such manner that it may be removed and sharpened, replaced, or otherwise repaired, and yet to provide a secure enough retention to prevent unintentional separation.

A particular advantage of the present invention is the facility with which the blade may be installed and removed and the fact that no special tools or other equipment are required for such purpose.

Still another advantage of the invention is the fact that the resilient insert which secures the blade on its holder accommodates minor variations in the construction of the blade and holder and thereby makes close tolerances of dimensions of the mating parts unnecessary, and further accommodates wear of parts with passage of time.

In one form of the invention, hereinafter described in detail, the resilient retainer is inserted in a hole in one of the mating parts extending outwardly from the hole so that it is contacted by the other mating part when the two members are forced together. The exposed end of the resilient insert is bent ito a groove formed in one of the parts and compressed between the bottom of the groove and the adjacent wall of the facing member. The cross-sectional shape of the groove is substantially different from the initial unstressed shape of the resilient insert 3,357,117 Patented Dec. 12, 1967 and hence there is considerable deformation of the insert which increases the area of surface contact. Hence the frictional resistance to unintentional dislodgment of the blade from the holder is increased.

Another principal feature of the present invention is the fact that neither bolts, metal keys, nor similar fasteners, nor welding to secure the blade on the shank are used, thereby eliminating a considerable amount of the difiiculty heretofore occasioned in securing blades to their holders and removing the blades from the holders when required.

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, partly broken away in section, showing a blade, holder and resilient insert, in accordance with one modification of the invention.

FIG. 2 is a side elevational View of the structure of FIG. 1, in assembled position.

FIGS. 3 and 4 are sectional views taken substantially along the lines 33 and 44, respectively of FIG. 2.

FIGS. 3A and 4A are views corresponding to FIGS. 3 and 4 of a modification.

FIGS. 5 to 8, inclusive, are views similar to FIGS. 1 to 4, respectively, of a modification.

FIGS. 9 to 12, inclusive, are views similar to FIGS. 1 to 4, respectively, of still another modification.

FIGS. 13 to 16, inclusive, are views similar to FIGS. 1 to 4, respectively, of a still further modification.

FIG. 17 is a perspective view of a harrow tooth, holder and associated elements.

FIG. 18 is an enlarged side elevational view of blade and holder in assembled position.

FIGS. 19 and 20 are sectional views taken substantially along the lines 1919' and 2020, respectively, of FIG. 18.

FIGS. 19A and 20A are and 20 of a modification.

FIG. 21 is a sectional view taken substantially along the line 21-21 of FIG. 20.

In the form of the invention shown in FIGS. 1 to 4, blade 11 is of a type suitable on heavy equipment of the type of road graders, rippers, dipper buckets, and other machines where blades of comparatively large size and heavy in weight are used and are subjected to severe stresses in unpredictable directions. A shank or a holder 12 is secured by means forming no part of this invention to a permanent part of the equipment and the blade 11 is held relative to shank 12 at an angle best suited for the performance of its function, such as that shown in FIG. 2. The lower end 13 of holder 12 is bent generally parallel to the working portion of blade 11 and then extends upwardly in a stretch 14 at an angle to portion 13.

views similar to FIGS. 19

curved to reduce resistance to the performance of the function of blade 11.

The shape of blade 11 is subject to considerable variation. In the form of the invention herein illustrated, the distal portion is formed with flat, broad, top and bottom surfaces 17, 18, top surface 17 being parallel to the direction of the tooth and the bottom surface 18 tapering upwardly to a broad, blunt, transverse, forward end 19. The proximal end of blade 11 has a downward extension 21, which is T-shaped in cross-section, extending longi tudinally of the tooth. More specifically, extension 21 has a leg 22 depending from the center of the bottom of blade 11, and its lower end is provided with a pair of J) outwardly extending feet 23. The bottom surface 24 of extension 21 is preferably flat, as are the sides of leg 22, whereas the corners 26 are rounded.

In the form of the invention of FIGS. 3 and 4, a hole 27 is formed, extending transversely through leg 22, adjacent the rearward end of the tooth and approximately midway between the underside of blade 11 and legs 23. Forwardly of hole 27 along the flanks of leg 22 are grooves 28. The cross-sectional area of each groove 28 is substantially less than the cross-sectional area of hole 27. The depth of groove 28, as measured horizontally in FIG. 3, is substantially less than the width of groove 28, as measured vertically, and said width is substantially greater than the diameter of hole 27. The reason for these dimensions in the preferred form of the invention will hereinafter appear.

The forward upper portion of extension 13 of holder 12 is slotted complementary to extension 21, in that it is formed with a top opening 31, having substantially parallel side edges 32 and widening out to lateral extensions 33. The distance between sides 32 is only slightly greater than the thickness of leg 22. The rearward end 34 of opening 31 is curved upwardly so as to provide an abutment for the rearward end of blade 11 when the blade is forced into holder 12, as shown in FIG. 2. Ordinarily, the fit between the mating parts is such that the blade and holder readily could be withdrawn relative to each other, if no locking means were employed.

Frictionally to hold the two parts together in assembled position, resilient insert 36 is used. Insert 36 is formed of a resilient material, preferably an elastomeric material such as neoprene synthetic rubber. However, natural rubber, other synthetic rubber, nylon cord, latex dipped nylon cord, soft iron wire, or other resilient substances may be used. The cross-sectional shape of insert 36 in its initial dimensions are slightly less than the corresponding dimensions of hole 27, so that the insert 36 may be slipped through hole 27 and extend transversely relative to the leg 22, perpendicular to the direction of insertion of the blade in the holder. The length of insert 36 is materially greater than the width of leg 22, so that in its position extending through hole 27 it projects outwardly to either side of leg 22. Accordingly, when blade 11 is pushed into holder 12, the exposed ends of insert 36 are engaged by end 30 and bent into grooves 28. By reason of the cross-sectional shape of groove 28, relative to the initial or uncompressed shape of insert 36, the exposed portions 37 are deformed to the shapes shown in FIGS. 3 and 4, conforming generally to the shape of grooves 28. The length of grooves 28 in a longitudinal direction is sufficient to accommodate the distortion of insert 36. It will further be seen, particularly with reference to FIG. 3, that the area of surface contact of deformed portion 37 with side edges 32 of holder 12 is of extended scope, as compared with what such area would be if the grooves 28 were less shallow and wide. Hence the frictional resistance to withdrawal of the tooth on the holder is augmented.

Once the tooth is inserted in the holder in the position shown in FIG. 2, the resistance against separation of the two members is very great despite the size and weight of the blade 11, and despite all forces tending to separate the two, many of which may, in use of the equipment on which the blade is installed, come from unexpected angles. Further, since the blade is held in its holder by the resilient insert 36, it is not necessary to make the clearance between the parts so tight that the force of digging action jams the blade into its holder so that it cannot be withdrawn. All that is necessary to separate the two parts is to hit the end 20 of the blade in a longitudinal direction from the rear with a hammer or other tool until the frictional resistance to separation is overcome.

FIGS. 3A and 4A show a modification in which tooth and holder are of the same shape as in the preceding modification, but hole 27 and grooves 37 are eliminated. Corresponding parts are marked with the same reference numerals. Transverse holes 127 are formed in end 13 directly opposite legs 22 adjacent the front terminus of end 13. Longitudinal grooves 128 are formed in sides 32 extending rearwardly of holes 127. The dimensional relationship between grooves 128 and holes 127 is as in the preceding modification. A resilient insert 136 is placed in one or both holes 127 and is deformed into the shape indicated by reference numerals 137 and function as in the preceding modification.

Turning now to the modification of FIGS. 5 to 8, inclusive, the relationship of the part is quite similar to the preceding modification, except that the shape of the mating portions of the tooth and holder are reversed. Since many of the parts are substantially identical, corresponding elements are designated by the same reference numeral followed by the Sllfi'lX a.

The proximal end of blade 11a is thickened and formed with a slot 41 which is T-shaped in cross-section. In other words, the walls 42 of slot 41 at the bottom are spaced relatively close together, with shoulders 43 above top edge 42 and laterally widened-out portions 44 on either side above shoulders 43, with a substantially flat top wall 46.

Grooves 51 are formed in the sides of the lower end of portion 13a of holder 12a to provide an H-shaped crosssection the upper part of which fits inside opening 41 with a fairly close tolerance. Thus the shape of portion 13a is such that there is a web 52 between grooves 51 of restricted width with lateral extensions 53 above web 52. It will be seen, particularly with reference to FIG. 7, that blade 11a is formed with inward projections 54 which fit into the space of grooves 51, with walls 42 in close engagement with the sides of web 52. The bottom 59 of portion 13a engages under projections 54.

Hole 27a extends transversely through web 52, adjacent the forward end thereof. Rearward of hole 27a, grooves 28a are formed in the side walls of web 52. Grooves 28a have a cross-sectional shape similar to the corresponding grooves 28 in the preceding modification, and the relation of the cross-sectional area of the grooves relative to the cross-sectional area of hole 27a is similar.

When the blade 11a is forced over the projecting end 13a of holder 12a, the exposed ends of insert 360 are bent backward in grooves 28a and deformed to the shape 37a, best shown in FIGS. 7 and 8, thereby frictionally impeding separation of the two members as in the preceding modification. Rearward movement of blade 11a is limited by the length of grooves 51, which are of reduced depth at their proximal ends. When it is desired to replace the blade, it may be driven off of the holder in a way similar to that explained with reference to FIGS. 1-4.

Turning now to the modification shown in FIGS. 9-12 inclusive, it will be seen that the blade 11b and holder 12b are generally similar to the preceding modification. Corresponding elements have been designated with the same reference numeral followed by the suflix b.

The cross-sectional shape of the opening 41!) in the proximal end of blade 11b is dovetail-shaped in that there is a substantially horizontal top surface 461) and downwardly converging side surfaces 42b.

The forward portion 13b of holder 12b has its upper portion complementary to the dovetail opening 41b in the blade Thus there is a flat top surface 53b and downwardly converging sidewalls 55 providing a web 5222 through which extends hole 27b. The depth of opening 41!) is such that the forward end 56 abuts and is limited in forward movement by the front wall 57 of said opening 41b. It will be understood, however, that other means may be employed to limit movement of blade 11b rela tive to holder 12b.

The modification of FIGS. 13-16 is quite similar to that of FIGS. 912 except for the shape of opening 41c and the corresponding complementary shape of web 520. Corresponding elements have been designated with the same reference numeral followed by the sufiix c. In this form of the invention the shape of the complementary portions is a flattened or truncated oval. Thus the top wall 46c is fiat and horizontal and the sidewalls 420 are oval, or inwardly curved rather than flat and straight as in the preceding modification. The lower end 500 of end 130 is substantially rectangular, although other shapes are also useful. Further, the web 520 has a top surface 530 and convex oval side walls 55c. The function of the resilient insert 360 is the same as in the preceding modification.

In FIGS. 5 to 16 inclusive, various cross-sectional shapes of the holder web and opening are illustrated. It will be understood that other shapes, such as round, full or partial oval or rectangular may be used. Further, in FIGS. 1-4 a shape complementary to the shape of FIGS. 58 is used. It will be understood that shapes complementary to that in the other modifications illustrated as previously mentioned also may be substituted.

The modification of FIGS. 17-23 are similar to the preceding modifications. The blade 71 is a harrow blade or a blade performing a similar function. Thus the blade 71 may be a plow or scarifier blade or a cable plow used in forming a furrow for installation of electrical cable. A vertical shank 72 of extended length is conventionally used to support blade 71, being fastened as by means of U-bolt 73 to a structural member 74 of the machine. Blade 71 is preferably formed with tips 76 at either end so that the blade may be reversed when one end is dull or broken. The lower end 77 of shank 72 is curved forwardly and blade 71 is curved to fit the curvature of the shank. Conventionally such blade 71 is bolted by means of a bolt (not shown) to the lower end of shank 72 to permit removal for replacement or inversion. The use of such a bolt is undesirable in that it weakens the blade, the fastening means may become disengaged or other difficulties occur. The use of the bolt is eliminated in accordance with the present invention.

Fitting 81 is welded as by welds 80 or otherwise secured to the back of blade 71. Fitting 81 is disposed longitudinally of the blade and is preferably of considerably lesser length than the blade. In cross-section extension 81 is T-shaped having a leg 82 of restricted width which is connected at its proximal end to blade 71 as by welding or integrally formed. Laterally extending arms 83 extend normal to leg 82. One or more holes 84 are formed transversely through leg or web 82, preferably there being one hole 84 adjacent each end of leg 82. Intermediate holes 84, or in any event communicating with each hole 84, is a groove 86 formed in the side wall 87 of leg 82. The cross-sectional shape of groove 86 as compared to hole 84 is in the same relationship as in the preceding modifications. In this form of the invention a resilient insert 88 of a shape such as to fit within one of holes 84 and of a length considerably greater than the width of leg 82 is used, the material of construction being the same as in the preceding modifications.

To receive fitting 81, the top surface of portion 77 is formed with a slot 91 having side walls 92 parallel to walls 87 and spaced apart a distance slightly greater than walls 87. Below side walls 92 are lateral extensions 93 which are dimensioned to receive arms 83.

In use, the particular point 76 which is to be the working point is placed downwardly and a resilient insert 88 inserted in the particular hole 84 remote from the point 76 in use. The ends of insert 88 project out beyond holes 84. The blade 71 is then assembled on shank 72, the fitting 81 being received in opening 91. As the blade is pushed backward the resilient insert 88 is compressed into grooves 86 and deformed in portions 94 as in the preceding modification. Removal of blade 71 is accomplished by hammering down on the point 76 not in use until frictional resistance is overcome.

Although a curved blade 71 is illustrated in the accompanying drawings, it will be understood that a flat blade may be used in cable plows and other installations. Plural inserts 88 may be used where required by reason of severe operating conditions.

FIGS. 19A and 20A show a modification of the structure of FIGS. 17-21, wherein holes 84 and grooves 86 in fitting 81 are eliminated. A pair of holes 96 is formed in the thickened portions 97 above arms 83a, said holes 96 being located near the distal end 77a of the shank. Grooves 98 are formed in portions 97 facing side walls 87a. The dimensional relationship between grooves 97 and holes 96 is as previously defined. A resilient insert 88a: is placed in one or both holes 96 prior to fitting 81a being inserted in slot 91a. The function of insert 88a is the same as in the preceding modifications and removal of the blade is similarly accomplished. Since many of the elements are very similar to those of FIGS. 17-21, the same reference numerals followed by sufiix a are used.

Although the foregoing invention has been described in some detail, by way of illustration and example for purposes 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:

1. In earth digging equipment, a blade holder member, a blade member and a resilient retainer for said members, a first of said members formed with a recess having at least one first wall, a second of said members formed with an extension complementary to said recess and having at least one second wall facing and in close proximity to said first wall, said extension sliding longitudinally into said recess, at least one said wall formed with a longitudinaly extending groove and a transverse hole, said retainer fitting in said hole and being compressed into said groove to frictionally restrain longitudinal relative movement of said members, said recess and said extension being T-shaped in cross-section having a leg and transverse feet and one said wall extending along said leg, said hole normal to said leg, said extension being completely enclosed within said recess, the walls of said recess surrounding said leg and said feet, said groove having a cross-sectional area substantially less than the initial uncompressed cross-sectional area of said retainer, said groove being substantially wider in a direction transverse to the direction of insertion of said blade member in said blade holder member than the depth of said groove, whereby the compressed shape of said retainer provides an extend surface of frictional contact between said members.

2. The combination of claim 1 in which said blade member is formed with said extension, said hole transverse through said leg.

3. The combination of claim 1 in which said blade member is formed with said extension, said hole formed in said blade holder member transverse to said leg.

4. The combination of claim 1 in which said blade member is formed with said recess and said blade holder member is formed with said extension and said extension formed with a bottom portion below said leg engaging the underside of said blade member, said hole transversely through said leg and said groove in a side of said leg.

5. In earth digging equipment, a blade holder member, a blade member and a resilient retainer for said members, said blade member formed with a dove-tailed recess having at least one first wall, a second of said members formed with a dovetailed extension complementary to said recess and having converging side walls, at least one side wall facing and in close proximity to said first wall, said extension sliding longitudinally into said recess, at least one said side wall formed with a longitudinally extending groove, a transverse hole between said side walls, said retainer fitting in said hole and being compressed into said groove to frictionally restrain longitudinal relative movement of said members, said groove having a cross-sectional area substantially less than the initial uncompressed crosssectional area of said retainer, said groove being substantially wider in a direction transverse to the direction of insertion of said blade member in said blade holder member than the depth of said groove, whereby the compressed shape of said retainer provides an extended surface of frictional contact between said members.

6. In earth digging equipment, a blade holder member, a blade member and a resilient retainer for said members, said blade member formed with a recess of truncated oval cross-section having at least one first wall, said blade holder member formed with an extension of oval crosssection complementary to said recess having inwardly curved side walls and having at least one said side wall facing and in close proximity to said first wall, said extension sliding longitudinally into said recess, at least one said side wall formed with a longitudinally extending groove and a transverse hole between said side walls, said retainer fitting in said hole and being compressed into said groove to frictionally restrain longitudinal relative movement of said members, said groove having a cross-sectional area substantially less than the initial uncompressed cross sectional area of said retainer, said groove being substantially wider in a direction transverse to the direction of insertion of said blade member in said blade holder member than the depth of said groove, whereby the compressed shape of said retainer provides an extended surface of frictional contact between said members.

7. In earth digging equipment, a blade holder member, a blade member and a resilient retainer for said members, said blade member formed with a recess, said recess of non-circular shape having a pair of first walls, said blade holder member formed with an extension of non-circular shape complementary to said recess and having a pair of second walls facing and each in close proximity to a first wall, said extension sliding longitudinally into said recess, at least one said second wall formed with a longitudinally extending groove and a transverse hole between said second walls, said retainer fitting in said hole and being compressed into said groove to frictionally restrain longitudinal relative movement of said members, said groove having a cross-sectional area substantially less than the initial uncompressed cross-sectional area of said retainer, said groove being substantially wider in a direction transverse to the direction of insertion of said blade member in said blade holder member than the depth of said groove, whereby the compressed shape of said retainer provides an extended surface of frictional contact between said members.

8. The combination of claim 1 which further comprises an extended tooth secured to said blade member, said tooth extending longitudinally, said extension being on said blade member and of substantially lesser length than said tooth.

The combination of claim 8 in which said blade is reversible end to end and said extension is reversibly insertable in said recess.

10. The combination of claim 9 in which one said hole is formed adjacent each end of said extension, said groove on said extension.

11. The combination of claim 9 in which said extension has one hole formed in said leg adjacent either end of said extension, said groove formed 011 the side of said leg.

12. The combination of claim 9 in which said hole is formed in said blade holder perpendicular to and intersecting said leg, said groove in said blade holder extending longitudinally opposite said leg.

References Cited UNITED STATES PATENTS 775,770 11/1904 Herrod 172751 X 2,222,071 11/ 1940 Gustafson 37142 X 2,968,880 1/1961 Petersen 37-142 3,057,091 10/1962 Petersen 37-142 ABRAHAM G. STONE, Primary Examiner.

A. E. KOPECKI, Assistant Examiner.

Claims (1)

1. IN EARTH DIGGING EQUIPMENT, A BLADE HOLDER MEMBER, A BLADE MEMBER AND A RESILIENT RETAINER FOR SAID MEMBERS, A FIRST OF SAID MEMBERS FORMED WITH A RECESS HAVING AT LEAST ONE FIRST WALL, A SECOND OF SAID MEMBERS FORMED WITH AN EXTENSION COMPLEMENTARY TO SAID RECESS AND HAVING AT LEAST ONE SECOND WALL FACING AND IN CLOSE PROXIMITY TO SAID FIRST WALL, SAID EXTENSION SLIDING LONGITUDINALLY INTO SAID RECESS, AT LEAST ONE SAID WALL FORMED WITH A LONGITUDINALLY EXTENDING GROOVE AND A TRANSVERSE HOLE, SAID RETAINER FITTING IN SAID HOLE AND BEING COMPRESSED INTO SAID GROOVE TO FRICTIONALLY RESTRAIN LONGITUDINAL RELATIVE MOVEMENT OF SAID MEMBERS, SAID RECESS AND SAID EXTENSION BEING T-SHAPED IN CROSS-SECTION HAVING A LEG AND TRANSVERSE FEET AND ONE SAID WALL EXTENDING ALONG SAID LEG, SAID HOLE NORMAL TO SAID LEG, SAID EXTENSION BEING COMPLETELY ENCLOSED WITHIN SAID RECESS, THE WALLS OF SAID RECESS SURROUNDING SAID LEG AND SAID FEET, SAID GROOVE HAVING A CROSS-SECTIONAL AREA SUBSTANTIALLY LESS THAN THE INITIAL UNCOMPRESSED CROSS-SECTIONAL AREA OF SAID RETAINER, SAID

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