US2263215A

US2263215A - Dipper tooth

Info

Publication number: US2263215A
Application number: US365114A
Authority: US
Inventors: Paul V Larsen
Original assignee: Pettibone Mulliken Corp
Current assignee: Pettibone Traverse Lift LLC
Priority date: 1940-11-09
Filing date: 1940-11-09
Publication date: 1941-11-18
Anticipated expiration: 1958-11-18

Description

" Nov. 18, 1941 P, v. LARSEN I 2,263,215

' DIPPER 'I'QO'IH Filed Nov. 9, 1940 I 2 sheets-sheet 1 2 Nov. 18, 1941. P. v. LARSEN DIPPER 'room Filed Nov. 9, 1940 2 Sheets-Sheet 2 v faulvparaenl, m \Q Patented Nov. 18, 1941 DIPPER TOOTH Paul V. Larsen, Chicago, Ill., assignor to Pettibone Mulliken Corporation, a corporation of Delaware Application November 9, 1940, Serial No. 365,114

8 Claims. (Cl. 37-142 This invention is directed to a dipper tooth. More particularly the invention is directed to the novel construction of the joint between the dipper tooth and the stub upon the lip of the dipper bucket.

Generally dipper teeth are made of very hard materials such as manganese steel, or alloy steel forgings. Teeth which constitute the digging points of the dipper are, of course, subjected to much wear and great stresses. Consequently they are made so that they can be replaced when worn. Great dimculty is experienced in constructing a tooth which can be easily made irom very hard steel alloys, and which can be connected to the stub so that it remains tightly seated thereon despite the working stress to which it is subjected, and at the same time can be easily replaced;

An object of this invention is to produce a connection between a dipper tooth and its stub which achieves increased strength and wearing qualities by providing a greater than ordinary bearing area between the teeth and the stub.

Another object of the invention is to produce a connection between a dipper tooth and its stub by means of which the dipper tooth canbe firmly and tightly seated upon the stub while at the same time the tooth can be easily replaced.

Another object of the invention is to produce a dipper tooth which is of simple construction and can be made with the minimumof machining and grinding. Likewise the stub is of correspondingly simple construction and can be produced with a minimum of machining and grinding.

Another object of the invention is to produce a novel key and slot construction for holding the dipper tooth to the stub.

Generally these objects of the invention are obtained by providing the dipper tooth point with opposed rearwardly diverging wings between which projects a shank of circular cross-section.

' This shank is adapted to be seated in a bore in the stub. The shank of circular section is flared into the dipper tooth body by means of filet-s which are tapered in plan, and the stub is shaped complementary to the flare, thus providing an increase of bearing surface between the dipper tooth body and the stub over and above that obtained, for example, by a shank of rectangular cross-section. The invention allows the stub to tie-constructed with plane surfaces on its top and bottom, and the bore for receiving the shank of the tooth is circular and easily molded and ground out if desired. The inner sides of the wings can be formed with a wedge-like crosssection, and the stub complementarily formed, so that the stub is locked against lateral displacement. The key for'fastening the tooth to the stub is brought very close to the tooth body and thus creates a stronger construction. The key itself is formed with its opposing sides of equal radii, and the key slots in the shank and stub, respectively, each have one side of corresponding radii so that a fully curvedsurface contact, rather than a line contact, is obtained between the key and the shank and the stub.

Generally the means by which the objects of this'invention are obtained are more fully shown in the accompanying drawings in which: Fig. 1 is a perspective view of a'dipper tooth constructed according to this invention; Fig. 2 is an enlarged plan view of the dipper tooth of Fig. 1; Fig. 3 is an enlarged side elevational view of the dipper tooth; Fig. 4 is an end elevational view of the dipper tooth; Fig. 5' is a perspective view of the stub for receiving the dipper tooth; Fig. 6 is an enlarged plan view of Fig. 5; Fig. 7 is an enlarged side elevational viewof the stub; Fig. 8 is an enlarged front elevational view of the stub; Fig. 9 is an enlarged side elevational view, partly in section, showing the connection between the dipp'er tooth and the stub;;,- Fig. 10 is an enlarged perspective view of the key; and Figs. 11, 12 and 13 are enlarged cross-sectional views, respectively, on the lines lll I, '29-: and I3--l3 of Fig. 9.

In Figs. 1 to 4, the dipper tooth or point A is. composed of a tooth body 2 and a shank 4.- Body 2 is wedge-shaped and has a solid forward point 6 forming a cutting edge'irom which rearwardly extending diverging wings 8 extend, it being apparent that these wings converge forwardly into the solid body portion 6 to form in the body a V-shaped opening, curved.

The under surfaces of the wings may be flat the bight III of which is the entire width of the tooth. The tooth illustrated has, however, an additional feature in that the under surface of each wing is inclined from the side of'the tooth to a median line 1, the inclination being of the order of 5 for a 4 inch point. These tapered surfaces coact with complementary surfaces on the stub to prevent sidewise movement of the tooth on the stub. This construction has the further advantage in that the tooth, when forged from an alloy steel, can be more readily removed from the die.

Shank 4 is of circular section, the diameter of which is less than the Width of tooth A, and is composed of a portion l4 lying between wings 8, and of a tapered portion I2 which extends rearwardly of wings 8. Because of the convergence of wings 8 toward the cutting edge 6 of the tooth, the portion i4 of shank 4 is merged into the converging space by curved fllets l6.

-. tact with wings 8 over a substantially U-shaped area, the outer edge u being shown tapered in plan as indicated by dotted lines upon Fig. 2. By reason of this shape of the filets l6, shank 4 is firmly secured to point 2, and substantially triangular surfaces 22 are created which constitute additional bearing areas for the resting of tooth A on stub B, over bearing surfaces achieved in prior art constructions. Of course, the under surfaces of wings 8 which lie laterally of shank 4 are also adapted to bear upon stub B, as is more extending making the tooth is symit is reversibly fully described later.

'Shank 4 has a longitudinal bore 24 therethroughfor the purpose of shank of lighter weight. As the metrical about its longitudinal axis, appliable to the stub. A keyhole fully described hereafter, extends vertically through portion I 2 of shank 4 immediately to 1 the rear of wings 8.

Stub B shown in Figs. 5 to 8, is of novel construction and is formed to complement the construction of tooth A. Stub B is composed of a body portion 30 adapted to be fixed to the dipper lip and is usually cast integral therewith, The tooth receiving end of body 30 is composed of forwardly converging

plane surfaces

32 and 34 terminating in a rounded end portion 36 which has substantially the same radius as bight ID in 'tooth A, the convergence of surfaces 32 and 34 j being the same as the convergence of the inner surfaces of wings 8 of tooth A which form the V-shaped opening referred to above. A bore 38 having a larger diameter than shank 4 to allow a loose fit of the shank in the bore, extends inwardly from end 36 into the body 30 of stub B.

Because of the diameter of this bore,

flanges

48 and 42 are formed, leaving the substantially U-shaped opening 46 in the end portion 01' stub B. When the tooth has the transversely inclined under wing surfaces, stub B must be comple-' mentarily formed, and in accordance therewith I] the bearing portions of

surfaces

32 and 34, in-

cluding the surfaces of

wings

40 and 42 are transversely inclined toward the center as shown. From Figs. 5 and 6 it is clear that each

flange

40 and 42 provides a bearing area having a width :1: adjacent the bight 45 of the U-shaped opening 46, said bearing area tapering toward the end 36. The bight 45, of course, is the same width as end l5 of the tooth A. The plan of this hearing area corresponds to the bearing surface 22 formed on the inner surface of each wing 8 by filets Hi. This bearing surface represents'an increase in bearing area over and above that which would be produced from a shank of rectangular cross-section for tooth A, and a corre-- sponding rectangular bore in stub B, as such a rectangular section, of corresponding strength, would leave

flanges

40 and 42 with a uniform 26, to be morewidth corresponding to the width of each end 36.

Stub B is further provided with a keyhole slot 48 which will be described in detail later.

When tooth A is assembled with stub B, the shank 4 enters into bore 38 (note Fig. 9) and fits loosely therein. The inwardly facing surfaces; 'g s fl gincludingfg tl surfaces 22, bear upo" riac'es of liahg'es ahd" 42;" and the ends 36 of stub B are slightly spaced from the bight I0 of tooth A. Filets l6 on tooth A lie between

flanges

48 and 42 on stub B and thus prevent tooth A from rotating on stub B. Because of the increagad bearing surfaces between the tooth and the stub, the tooth is further pre vented from turning upon the stub, and is tightly held thereon when a key is inserted through

keyhole slots

26 and 48 respectively. In addition, the transversely inclined under surfaces of the wings, and the complementarily shaped stub, as illustrated by the form of the inventio'n shown in the drawings, prevent sidewise displacement of the tooth upon the stub, thus greatlyreducing the possibility of wear between the two.

Tooth A can be very easily cast, with a minimum of simple grinding, if necessary. Likewise stub B is very simply molded because of its fiat and/or planar upper and

lower surfaces

32 and 34, and of the ease with which the bore 38 can be formed. "If the bore 38 is imperfectly cored it can be easily ground out by means of a grinding wheel insertedtherein. As point A overlaps stub B and is tightly seated thereon, projecting portion I 2 of shank 4 need only be of a length sufficient to receive key slot 26.

The novel key and keyhole construction is more fully shown in Figs. 9 to 13, inclusive. The

keyholes

26 and 48, respectively, are wedge-shaped with sides y and y of small radius and sides z and z of larger radius. The radii of sides 1 and y are all equal, and likewise the radii of sides 2 and z are equal, although this latter is not essential. The key 50 shown in Fig. 10, is longitudinally tapered and-has its sides 52 and 54 formed in a curve, the radius of which is equal to the radius of sides 1/ and y of the keyhole slots. Consequently whenithe key is inserted into the keyhole slots, as shown in Figs. 9 and 11 to 13, the sides 52, 54 of the key will form a full surface contact, and will provide a firm bearing connection with the keyhole slots. The sides a and z of the keyhole slots being of larger radius than the sides 1/ and y allow the key to be inserted into the keyholes without jamming and permit the key to be seated in full surface contact with the sides 1/ and 11'. Heretofore prior art key slots have had a larger radii and a larger width than the key and consequently the key only made a line contact with the surface of the key slots. This permitted some lateral play in the joint, which play caused gradually increasing wear upon the key slot when the dipper was being operated. Increase of wear, of course, means that the tooth becomes loose upon the stub and bending stresses are introduced which lead to the failure of the tooth. By reason of the novel key construction of this invention such loosening of the tooth is prevented because no play can take place in the key-and slot construction.

The means by which the objects of this invention are accomplished having now been de-,

scribed, I claim:

1. A dipper tooth construction comprising a wedge-shaped tooth having forwardly converging spaced wings, a shank of circular section extending from between said wings rearwardly thereof, filets uniting said shank to said wings, a stub complementarily shaped to said shank and fllets, and that portion of said shank included between said wings being gradually tapered forwardly toward the'longitudinal axis of the said tooth.

2. Adipper. tooth as in claim 1, the contacting surfaces of the said wings being inclined transversely toward the center line and tapering toward the edges of the said wings, and'the stub contacting surfaces being inclined transversely toward and tapering inwardly to the said center line.

3. A dipper tooth comprising a wedge-shaped point having a solid apex portion and two forwardly converging spaced wings, a shank of.circular section extending between and rearwardly of said wings, and filets uniting said shank to said wings, each filet being tapered in plan from the rear toward the front of the tooth with the rear portion of each diet being of substantially less width than the diameter of said shank.

4. A dipper tooth as in claim 3, said fllet having a width of approximately one-third the diameter of said shank at its rearmost end, and being tapered to awidth of approximately the diameter of said shank toward the pointed end a width substantially equal to said diameter at the forward edge of said shank; a stub having forwardly converging upper and lower plane surfaces complementary to the opening between said wings, a bifurcated end portion complementary to said filets, and a bore for receiving said shank; said tooth being seated upon said shank with the inner surfaces of said wings bearing upon said converging surfaces of said stub, said shank being fitted in said core, and said bifurcated end embracing opposite sides of a portion of said shank.

6. A dipper tooth construction as in claim 5 furthercomprising key means for securing said shank to said stub. v

7. A key and slot construction for securing the shank of a dipper tooth to a .stub comprising a key slot in said shank having one side curved on a relatively small radius and an opposite side curved on a relatively large radius, a second key slot in said stub having curved sides similar to those in said shank, but i'eversely positioned with respect to the sides in said shank, and a keyinserted into the aligned slots, said key having two opposite sides curved the same as said relatively small radius sides of the slots.

8. A key and slot construction for securing the shank of a dipper tooth to a stub comprising wedge-shaped-and oppositely directed key slots in said shank and stub, the smaller sides of said slots being similarly curved, and a key inserted in said slots, said key having two opposed sides curved similar to the curve of said smaller sides in said slots whereby the opposed sides of said key make a full surface contact with said smaller sides when said key is fitted in said slots.

PAUL V. LARSEN.