US3574962A

US3574962A - Earthworking tip mounted for limited pivotal movement

Info

Publication number: US3574962A
Application number: US782843A
Authority: US
Inventors: Roger M Smith
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1968-12-11
Filing date: 1968-12-11
Publication date: 1971-04-13
Anticipated expiration: 1988-04-13

Abstract

An earthworking tip for mounting upon a wedge-shaped shank, a rearward portion of the tip having an I-beam configuration in cross section with top and bottom flanges generally mating with the wedge-shaped shank and a vertical web integrally joining the flanges and mating with a vertical slot in the shank.

Description

United States Patent inventor Roger M. Smith Joliet, Ill. Appl. No. 782,843 Filed Dec. 11, 1968 Patented Apr. 13, 1971 Assignee Caterpillar Tractor Co. Peoria, 111.

EARTHWORKING TIP MOUNTED FOR LIMITED PIVOTAL MOVEMENT 3 Claims, 3 Drawing Figs.

US. Cl. 3 142R, 172/713 Int. Cl E02f 9/28 Field of Search .v 37/ 142; 172/713 References Cited UNITED STATES PATENTS 851,093 4/ 1907 Kennedy 37/ 142 Clark Van Buskirk et a1. Van Buskirk McKee et a1 McKee Mekeel Anderson Mur'taugh Baer Larsen et a1.

Primary Examiner-Edgar S. Burr A ttorney- Fryer, Tjensvold, Feix, Phillips & Lempio ABSTRACT: An earthworking tip for mounting upon a wedge-shaped shank, a rearward portion of the tip having an 1- beam configuration in cross section with top and bottom flanges genera11y mating with the wedge-shaped shank and a vertical web integrally joining the flanges and mating with a vertical s1ot in the shank.

Patented April 13, 1971 H mw M N5 E v WM ATTORNEYS EARTIIWORKING TIP MOUNTED FOR LIMITED PIVOTAL MOVEMENT Earthworking tips are commonly employed upon various types of machinery for ripping or loosening earth as well as other materials. Very substantial load forces result within the tips from their engagement with the earth. The tips must be structurally sound in order to withstand these forces. In addition, even tips constructed of highly abrasion resistant materials tend to wear away and must be replaced at frequent intervals. Accordingly, it is desirable to replaceably mount the tips upon a suitable supporting shank in a manner so that the tips upon a suitable supporting shank in a manner so that the tips may be readily replaced in the field without the need for special tools or equipment. Because of the very large forces involved, the tips tend to be driven further onto the supporting shank so that unless they are designed to resist wedging or locking interaction with the shank, removal of the tips may be made very difficult A commonly employed earthworking tip in the prior art, which has been found to be satisfactory under the above conditions, has a deep tapered cavity which receives a tapered nose portion of the shank. A retaining pin or other means is employed to secure the tip upon the shank. Tips of this design have been found to be unsatisfactory at least from the standpoint of economy.

Generally, retaining tips may be cast but preferably they are forged or fabricated to provide increased strength and improved wear properties. The deep cavity is particularly difficult and expensive to form by either of these processes. On the other hand, the shank is commonly formed by casting for similar purposes of economy since the shank is not normally in constant engagement with the earth. This raises an additional problem with this type of earthworking tip. Since the tapered shank portion is completely enclosed within the tip, it is difficult for the operator to determine when the tip is nearly worn through. For this reason, the tip frequently wears away during operation so that the cast shank is exposed to highly abrasive engagement with the earth. Severe deformation of the shank commonly follows so that it must sometimes be replaced along with the earthworking tips.

The present invention provides an earthworking tip which may be more economically formed by fabrication or forging and which minimizes or eliminates the other problems referred to above. A rearward portion of the earthworking tip has an I-beam configuration in cross section with inclined flange portions and a vertical web making up the I-beam configuration. The tip is suitable for mounting upon a shank having a wedge-shaped nose portion which forms a central vertical slot. The vertical web of the tip is disposed within the central slot to engage a rearward surface of the shank and prevent the tip from being locked upon the shank. This feature of the invention also prevents large shear stresses from arising in means such as a retaining pin for securing the tip on the shank. In this manner, the retaining tip of the present invention may be readily formed to exhibit increased strength and wear properties.

The I-beam configuration of the tip provides increased structural strength. The configuration of the rearward surface of the vertical web on the retaining pin to transfer substantially all load forces from the tip to the shank prevents shear stresses from arising in the retaining pin and also prevents the tip from becoming locked upon the shank. In this manner, the earthworking tip is reliably secured upon the shank while the retaining pin may be easily removed and the tip readily replaced upon the shank. The operator may readily observe the thickness of those parts of the tip which are most commonly eroded by engagement with the earth. It is therefore easier to determine the proper time for replacing the tip so that the shank may be substantially protected from abrasive wear.

Other objects and advantages of the invention are made apparent in the following description having reference to the accompanying drawing.

I shank taken along section line III-III of FIG. 1.

Referring now to the drawing and particularly to FIG. 1, an earthworking tip 11 according to the present invention is secured to a wedge-shaped portion 12 of a supporting shank 13 by means of a retaining pin 14. The shank 13 is preferably formed by casting and has a shin guard 16 secured by another retaining pin 17 to protect the forward shoulder of the shank above the earthworking tip from abrasive engagement with earth or other material.

Referring also to FIGS. 2 and 3, the wedge-shaped shank portion 12 extends forwardly from a more massive portion of the shank indicated at 18. The shank portion 12 defines a vertical slot 19 which extends rearwardly through the wedgeshaped portion of the shank to a forward facing surface 21 formed generally by the massive portion 17 of the shank. The wedge-shaped shank portion 12 also defines a horizontal bore 22 which extends transversely across the vertical slot 19 to receive the retaining pin 14.

The earthworking tip has a leading portion 23 for initially engaging and loosening earth with an integral vertical web 24 extending rearwardly from the leading portion 23. Upper and

lower flange portions

26 and 27 respectively are integrally joined by the vertical web 24 to present an I-beam configuration in cross section as is best seen in FIG. 3. The

flange portions

26 and 27 are inclined outwardly and towards the rear of the earthworking tip to generally mate with the upper and lower extremities of the wedge-shaped shank portion 12. The

flange portions

26 and 27 also slightly overlap the wedge-shaped shank portion 12 to protect it from abrasive engagement with ground or other material being worked by the tip.

The I-beam configuration of the earthworking tip substantially enhances its structural strength and enables it to withstand large force loads arising from engagement with the ground. The central vertical web 24 is designed to transfer the force loads from the earthworking tip into the massive portion 18 of the shank. The width of the vertical web 24 is only slightly less than the width of the receiving slot 19 to substantially prevent sidewise motion of the tip upon the shank.

It is desirable that the

flange portions

26 and 27 of the earthworking tip remain slightly spaced ap in from the wedge portion 12 of the shank so that the tip will not become wedged or locked upon the shank and make replacement of the tip more difficult. To accomplish this purpose and to substantially eliminate shear forces in the retaining pin 14 which might cause its failure, a rearward surface '18 of the vertical web 24 is arcuately shaped so that a portion of the surface 28 always contacts the shank surface 21 to transfer force loads from the tip into the shank portion 18. The vertical web 24 is of a suitable length so that contact of the arcuate surface 28 with the shank surface 21 maintains the desired gap between the

flange portions

26, 27 and the wedgeshaped shank portion 12. Because of the gap maintained between these portions, the earthworking tip may tend to rotate slightly about the axis of the retaining pin 14 as it comes into engagement with the ground. The arcuate shaping of the surface 28 insures that a portion of the vertical web 24 is always effective to transfer the load forces from the tip to the shank as discussed above.

The earthworking tip and the wedge-shaped portion 12 of the shank are symmetrically formed about a longitudinal centerline passing through the retaining pin 14 and generally indicated by the rearward portion of the section line II-II in FIG. 1. In this manner, the earthworking tip may be reversed upon the shank to maintain a sharp point on the tip and to provide for more even wear.

Iclaim:

1. An earthworking tip for mounting on a shank having a forward wedge shaped portion defining a vertical central slot and having a generally flat, forwardly facing surface at the rear of the slot, the tip having a rearwardly extending vertical web disposed in the vertical slot of the shank with top and bottom flanges integrally forming an l-beam configuration in cross section together with the web, the flanges being inclined similarly as the wedged shank portion to generally mate therewith, a rearwardly facing surface of the web being arcuately formed for constant and uniform engagement with the generally flat, forwardly facing surface at the rear of the shank slot, the width of the web along its length being only slightly less than the width of the receiving slot in the shank to limit sidewise motion of the tip on the shank and to provide strength in the web, means mounting the tip for limited pivotal movement relative to the shank including retaining means for 2. The earthworking tip of claim 1 wherein the retaining means for securing the tip to the shank comprises a pin passing through generally horizontal and transverse bores formed in the wedged shank portion and the vertical web of the tip.

3. The invention of claim 1 wherein the wedge-shaped shank portion and at least a portion of the tip which is adjacent thereto are symmetrically formed in order to permit reversing of the tip and provide for more even wear on the tip.

Claims

1. An earthworking tip for mounting on a shank having a forward wedge-shaped portion defining a vertical central slot and having a generally flat, forwardly facing surface at the rear of the slot, the tip having a rearwardly extending vertical web disposed in the vertical slot of the shank with top and bottom flanges integrally forming an I-beam configuration in cross section together with the web, the flanges being inclined similarly as the wedged shank portion to generally mate therewith, a rearwardly facing surface of the web being arcuately formed for constant and uniform engagement with the generally flat, forwardly facing surface at the rear of the shank slot, the width of the web along its length being only slightly less than the width of the receiving slot in the shank to limit sidewise motion of the tip on the shank and to provide strength in the web, means mounting the tip for limited pivotal movement relative to the shank including retaining means for securing the tip to the shank with the arcuately formed rearwardly facing surface of the web being arranged on the tip relative to the flanges to engage the generally flat surface at the rear of the forwardly facing shank slot prior to locked engagement of the tip upon the wedge-shaped shank portion and to remain in constant engagement with the forwardly facing surface at the rear of the shank slot so that substantially all load forces are transferred therebetween regardless of pivotal motion of the tip upon the shank.

2. The earthworking tip of claim 1 wherein the retaining means for securing the tip to the shank comprises a pin passing through generally horizontal and transverse bores formed in the wedged shank portion and the vertical web of the tip.