US 3675350 A
The assembly includes nonadjacent inclined wedging surfaces on a support in contact with similar surfaces in the cavity of a tooth capped over the support, and a resilient retainer pin to hold the wedging surfaces in contact.
Claims available in
Description (OCR text may contain errors)
United States Patent Mulchy et al.
 DIPPER TOOTH ASSEMBLY  inventors: l-lu-ry W. Mulcnhy, Lansing; Thoma 1!.
Russell, South Holland, both of ill.
[ 73] Assignee: AMS'I'ED Industries Incorporated,
 Filed: April 13, 1970  Appl. No.: 27,489
[ 1 Julyll, 1972 Primary xaminerEdgar S. Burr Attorney-Walter L. Schlegel, Jr. and Ruse]! W. Pyle  US. CL ..37/142 A, 299/92 [51 lnLCL ..E02l9/28 AB C  flddolSeu-rh ..37/l42; 299/92 The mmbly includes mnadjacem inclined Hedging surfaces on a support in contact with similar surfaces in the cavity of a  Rd cited tooth capped over the support, and a resilient retainer pin to UNITED STATES PATENTS hold the a s Mm in Contact 2,982,035 5/l96l Stephenson ..37/l42 R 3 China, 7 Drltlrhl' gum PATENTEDJUL 1 1 1912 SHEET 10F 2 01 2615 fiUSS/Z w: of W M QQ PATENTEDJUL H 1912 3,675,350
sum 20F 2 mrrsn room ASSEMBLY BACKGROUND OF THE INVENTION l Field of the Invention This invention relates to dipper teeth assemblies for excavating equipment and more particularly to such assemblies comprising a base or adapter with a replaceable tooth or point capped over said adapter in telescoping relationship.
2. Description of the Prior Art It has become common practice in the earth digging industry to provide diggers, scrapers, shovels, and the like with removable digging teeth or points releasably secured to a sup port for quick replacement; the support in turn is secured to a power apparatus.
Examples of dipper tooth assemblies similar to that herein described may be found in patents to Whisler US. Pat. No. 2,901,845, to Opsahl US. Pat. No. 2,921,391, and to Day U.S. Pat. No. 2,927,386, wherein the tooth has a wedge shaped cavity that is fitted over a wedge shaped support. A removable retaining device is commonly used to retain the tooth on the support.
One of the difficulties experienced in the use of removable tooth assemblies is the possibility of relative interaction between the surfaces of the tooth cavity and the mating surfaces of the adapter. The lack of close tolerances or a loose fit between such interfitting parts may allow excessive vertical and lateral displacement of the tooth relative to the adapter, thereby causing excessive and premature frictional wear on the contacting surfaces, which may require replacement of both the point and adapter.
An object of the invention, therefore, is to provide a dipper tooth assembly that will remain tight and stable throughout the life of the tooth.
SUMMARY OF THE INVENTION Accomplishment of the above object resides in the provision of an assembly wherein the tooth is in contact with the support only in planes disposed at oblique angles with respect to the longitudinal horizontal and vertical center planes of the assembly, said tooth being substantially spaced from said support along planes substantially parallel to said center planes, and in the provision of a suitable retainer to maintain said tooth in tight mating relationship with said support in the area of said angularly disposed planes, i.e., in the four corners of the polygonal cross-section of the mating tooth and support members.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1. is a perspective view of a dipper tooth assembly that incorporates features of the presently described invention;
FIG. 2 is an elevational view of the structure shown in FIG.
FIG. 3 is a plan view of the structure shown in FIGS. 1 and FIG. 4 is a cross sectional view taken along section line 4-4 of FIG. 2;
FIG. 5 is a cross sectional view taken along section line 55 of FIG. 2;
FIG. 6 is a detailed elevational view of the retainer pin shown in FIG. I; and
FIG. 7 is a plan view of the retainer pin shown in FIG. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1-5, a dipper tooth assembly is shown comprising a base or adapter 10 and a point or tooth I2 mounted on or capped over the base. The adapter 10 comprises upper and lower jaws l4 and 16 diverging rearwardly (to the right in the Figures) to form a recess 18, which enables attachment of the base to a shovel or similar part (not shown). F orwardly of the base, the jaws merge with each other to form a wedge-shaped nose 20, which comprises forwardly sloping or converging upper and lower inclined surfaces 22 and 24,
and spaced substantially parallel or slightly forwardly converging side surfaces 26 and 28. As best shown in FIGS. 4 and 5, the nose also comprises four planar wedging surfaces 30.32.34, and 36 which connect the upper and lower inclined surfaces 22 and 24 to their respective adjacent side surfaces 26 and 28.
It may be seen that the nose 20 and tooth 12 are substantially symmetrical about a common central longitudinal axis X)(, which axis is disposed at a slight downward angle relative to the central longitudinal axis X X of the jaws 14 and 16. The inclined surfaces 22 and 24 of the nose are substantially normal to the vertical plane passing through the central longitudinal axis X-X, whereas the side surfaces are substantially normal to the horizontal plane through axis X--X. The wedging surfaces 30,32,34 and 36 located in the four corners of the vertical cross-section of the nose, slope forwardly at about the same degree of slope as the respective upper and lower inclined surfaces 22 and 24 and also slope outward to the side so a to be oblique angularly disposed to the vertical and horizontal planes through axis X-X. The surfaces of the nose therefore substantially define a polygonal pyramid or polyhedron merging forwardly in an end surface 38 extending laterally on the nose 20 in the horizontal plane.
The nose 20 further comprises upper and lower central recesses 40 and 42 (Fig. 4) in the respective upper and lower inclined surfaces 22 and 24, which present respective upper and lower flat parallel inset surfaces 44 and 46. The recesses 40 and 42 are spaced from the side surfaces 26 and 28, and the inset surfaces are substantially parallel to the horizontal plane through axis XX. A vertical aperture 48 is provided through the nose 20 in the area of the inset surfaces 44 and 46 to receive a retainer pin 51 as will be hereafter explained.
The tooth I2 is generally a wedge-shaped structure having an external outstanding rib 50 around the outer perimeter of both outer converging surfaces 52 and 54 thereof, with triangular spaced side surfaces 53 and 55 interconnected with said converging surfaces. An openend, wedge shaped cavity 56 is provided in the larger end of the tooth, said cavity being of sufficient size and shape to accept the nose 20 of the adapter. As best shown in FIG. 5, the cavity thus comprises upper and lower forwardly converging surfaces 58 and 60, a pair of spaced side surfaces M and 62, and respective flat upper and lower pairs of wedging surfaces 64,66, and 68,70 (FIGS. 4 and S), which angularly connect the upper and lower converging surfaces to said side surfaces and are complementary to the wedging surfaces of the nose, being located in the four corners of the vertical cross section of the tooth cavity. The wedging surfaces 64,66,68 and 70 of the cavity slope forwardly at about the same degree as the upper and lower converging surfaces 58 and 60 and also slope outward to the side from said converging surfaces on an oblique angle with respect to the vertical and horizontal planes through axis X-X. The surfaces of the cavity therefore define a polygonal pyramid polyhedron merging forwardly in a forward end surface 72.
The point or tooth also comprises internal upper and lower central ledges 74 and 76 (FIG. 4) in the respective upper and lower converging surfaces 58 and 60 of the cavity, said ledges being spaced from the side surfaces 60 and 62 of the tooth and presenting respective upper and lower flat parallel surfaces 78 and 80 corresponding to the respective flat inset surfaces 44 and 46 of the nose 20. A pair of aligned substantially vertical apertures 82 and 84 are provided through the tooth in the area of respective flat surfaces 78 and 80.
The assembly is designed such that when assembled, the nose 20 and tooth cavity are spaced from one another except in the area of nonadjacent wedging surfaces, which are in contact. Thus, the corresponding pairs wedging surfaces 64-30, 66-32, 68-34 and 70-36 of the nose and cavity are normally in contact with corresponding pairs of wedging surfaces being nonadjacent to other such pairs whereas the corresponding upper and lower converging surfaces 22-58 and 24-60. the side surfaces 26-61 and 28-62, and the end surfaces 38-72 are normally spaced from one another, such that all the load is borne on at least two pairs of diametrically opposed wedging surfaces. It has been found that if the corresponding wedging surfaces are urged into interengagement by a retaining mechanism or by other suitable means, vertical and horizontal movements of the tooth relative to the support will be minimized.
As best shown in FIGS. 1, 6 and 7, a resilient retainer pin 51 is preferably employed in the assembly, said pin comprising a first rigid member 85 having an upper head 86 at one end thereof extending at a right angle from said first member, a second rigid member 87 spaced from said first member and located under and preferably abutting said head, and a resilient member 88 bonded to and interconnecting said first and second members. When viewed in plan (FIG. 7), both rigid members present arcuate or inwardly tapered outer surfaces. When viewed in elevation (FIG. 6), the first rigid member 85 presents upper and lower inclined outer surfaces 89 and 90, each of which incline toward its respective adjacent end. It may be seen also from HO. 7, that the pin is tapered from the first member 85 to the second member 87 in conformity with a taper in the head 86 when viewed in plan. Thus, the head 86 presents inclined side surfaces 91 and 92 converging toward the second, narrower member 87. The second member 87 is also rounded or tapered at the end remote from the head 86 to facilitate insertion of the pin into the dipper tooth assembly.
Referring again to FIGS. 2 and 3, it may be seen that the aligned apertures 82 and 84 in the tooth are forwardly ofiset from the aperture 48 in the nose, when the tooth is fully assembled on the nose. in this manner, insertion of the pin 51 causes the tooth to be urged into firm engagement with the nose, thereby bringing the aforesaid wedging surfaces into contact. The second or forward rigid member 87 of the pin contacts only the forward surface of the nose aperture 48, and the first or rearward rigid member 85 contacts only the rearward surfaces of the respective tooth apertures 82 and 84. The apertures 48, 82 and 84 are arcuate or inwardly tapered and properly sized to conform to the shape of the pin.
Means are provided to lock the retainer pin 51 in the assembly. The rear surfaces 93 and 95 (FlGS. l and 2) of the respective apertures 82 and 84 are forwardly inclined toward their respective outer surfaces 52 and 54 corresponding to the inclined surfaces 89 and 90 of the first member 85 of the pin. After insertion, the pin is locked in position by means of its inclined surfaces and rotation of the pin is prevented by reason of the interfitting or complementary tapered configurations of the pin and apertures.
Having thus described the invention, what is claimed is:
l. A dipper tooth assembly comprising a support with a wedge-shaped nose member and a tooth point member having an open-ended wedge-shaped cavity in telescoping relationship with said nose member, said telescoped members having a common longitudinal axis, said assembly comprising corresponding pairs of converging upper and lower surfaces on said nose member and in said cavity respectively normal to a vertical plane containing said axis, corresponding pairs of side surfaces on said nose member and in said cavity normal to a horizontal plane containing said axis, and wedging surfaces connecting said upper and lower surfaces of the nose member and cavity respectively and disposed at oblique angles to said planes, said wedging surfaces each comprising a single planar surface on one of the four corners of the nose member and in one of the four comers of the cavity respectively and being the sole areas of contact of said members when the members are in operative telescoped relation, and aligned apertures in said members with a resilient pin therein urging said members into said operative telescoped relationship.
2. The dipper tooth assembly of claim 1. wherein said resilient pin comprises elongated first and second rigid members each having outer surfaces and substantially parallel inner surfaces, an elongated resilient member bonded to and interconnecting said inner surfaces, said first rigid member havin a head at its upper end extending at a ri ht angle there rom and overlying said resilient member an partia ly overlying and abutting the upper end of said second rigid member, at least one of said rigid members having the lower portion of its outer surface downwardly and inwardly inclined, and said first and second rigid members providing a bifurcated opening in the lower end of the pin.
3. A dipper tooth assembly comprising a tooth point with an open end cavity, a forwardly projecting nose symmetrical about a horizontal plane, said nose defining side surfaces symmetrical about a vertical plane and a plurality of upper and lower wedging surfaces forming oblique angles with both of said planes, said upper and lower wedging surfaces converging forwardly toward said horizontal plane, said nose further defining a first connecting surface between said upper wedging surfaces and a second connecting surface between said lower wedging surfaces, said connecting surfaces converging forwardly toward said horizontal plane, said tooth point defining surfaces in said cavity complementary to said nose surfaces to allow engagement of said point in telescoping fashion on said nose, said upper and lower wedging surfaces defined by said nose and their complementary surfaces defined by said point each comprising a single planar surface on one of the four corners of the nose and in one of the four corners of the cavity respectively and being the only surfaces in contact when said point and said nose are engaged in telescoping fashion, whereby bearing strength and resistance to lateral loading are increased while still maintaining a secure attachment of the point on the nose.