GB2132980A - Ripper tip for digging teeth - Google Patents

Abstract

A tip for an earth digging tooth including a gear tip portion having a cavity for attachment to the tooth and a forward tip portion integrally formed with the rear tip portion. The tip is tapered and has a pair of ribs formed on the top surface at both lateral ends thereof. A smoothly curved step is formed between the top surface of the forward tip portion and the top surface of the rear tip portion. Each rib extends from the forward end of the top surface of the rear tip portion and terminates in a intermediate of the top surface of the forward tip portion.

Description

SPECIFICATION Ripper tip for digging teeth The present invention relates to an excavation blade such as a ripper tip attached to the extreme end of a ripper shank of a ripper device mounted on a construction machine, and excavation tip attached to an excavating bucket.

A ripper tip attached to the extreme end of a ripper shank of a ripper device heretofore known is provided with a socket portion or rear portion having a cavity fitted into the extreme end of the ripper shank and a tapered forward excavation portion, wherein upper and lower surfaces of the excavation portion and upper and lower surfaces of the socket portion are made to be continuous with each other at a predetermined angle, and a pair of left and right ribs are integrally formed between both sides of the upper and lower surfaces of the excavation portion and the extreme ends of both sides of the upper and lower surfaces of the socket portion.

In the above-described ripper tip, the strength of the excavation portion and of a connecting portion between the excavation portion and the socket portion can be increased by the left and right pair of upper and lower ribs. On the other hand, when the excavation portion wears and the pointed forward end becomes blunt, the left and right pair of upper and lower ribs reach the extreme forward end, and therefore, the upper and lower ribs increase in wall thickness in their extreme forward end to deteriorate the excavatability, as a consequence of which the ripper tip cannot be used up to its wear limit (the state wherein the excavation portion becomes worn to a portion in the neighbourhood of the socket portion).

That is, if the wall thickness is thick, the ripper tip uselessly, slips along the surface of rock without engaging into the rock, the extreme end of the ripper tip locally increases in temperature (300 - 700"C), and the ripper tip is lowered in hardness to faciiitate wear of the ripper tip (abnormal wear).

To prevent this, if an arrangement is made so that the excavation portion is made to decrease its wall thickness to make the whole shape sharp whereby the wall thickness is not increased even if wear occurs, the ripper tip becomes easily engaged in the rock to enhance the excavatability. This means that the excavatability enhances and no abnormal wear in ripper tip occurs.

However, if this arrangement is employed, the strength is lowered and a breakage tends to occur.

Therefore, it is not possible for the excavation portion to become excessively thin.

As described above, the excavatability and strength are in the relation of contradiction to each other, and therefore, it has been difficult to develop a ripper tip which is excellent in excavatability and high in strength.

It is therefore an object of the present invention to provide a digging tooth tip which is both durable and economical. Another object of the present invention is to provide a digging tooth tip wherein the tip does not become too thick even if it is worn.

In accordance with an aspect of the present invention, there is provided a replaceable tip for an earth digging tooth, comprising: a rear tip portion having means for attachment to said tooth, said rear rip portion having top and bottom surfaces which are converging forwardly; a foward tip portion integrally formed with said rear tip portion and having top and bottom surfaces and side surfaces extending from said rear tip portion to a transverse forward edge of said tip, the top and bottom surfaces of said forward tip portion diverging rearwardly from the transverse forward edge of said tip and terminating in the top and bottom surfaces of said rear tip portion, there being smoothly curved step formed transversely across the tip for connecting the top surfaces of said forward and rear tip portions; and a pair of ribs formed on the top surface of said forward tip portion at both lateral ends thereof, each rib being extending from the forward end of the top surface of said tip portion and terminating in an intermediate portion of the top surface of said forward tip portion.

The above and other objects, features and advantages of the present invention will be readily apparent from the following description taken in conjunction with the accompanying drawings.

Figure 1 is a side elevational view of a digging tooth tip according to the present invention; Figure 2 is a top plan view thereof; Figure 3 is a rear end view thereof; Figure 4 is a front end view thereof; Figure 5 is a cross-sectional view taken along the line V-V of Figure 1; Figure 6 is a cross-sectional view taken along the line VI-VI of Figure 12; Figure 7 is a cross-sectional view taken along the line VII-VII of Figure 1; Figure 8 is a cross-sectional view taken along the line VIII-VIII of Figure 1; Figure 9 is a side elevational view of another embodiment of the present invention; and Figure 10 is a similar to Figure 6 but explanatory of wearing condition of the digging tooth tip.

The present invention will now be described in detail below the reference to the accompanying drawings.

A pointed end-shaped excavation portion or forward tip portion 20 is connected to and formed integral with the extreme forward end of a socket portion or rear tip portion 11 having a cavity 10 fitted into the extreme forward end of a ripper shank.

Both side walls 12, 13 of the socket portion 11 are respectively formed with holes 14 for receiving a pin, and upper and lower walls, 15, 16 are inclined to be convergent forwardly and are symmetrical relative to the longitudinal centre plane X of the cavity 10.

The excavation portion 20 is formed to be continuous to and integral with the upper and lower walis 15,16, and upper and lower surfaces 21, 22, are inclined towards the extreme forward ends thereof into a pointed end shape, the upper surface 21 assuming a position slightly higher than the longitudinal centre plane X of the cavity 10 and being continuous of the upper wall 15 of the socket portion 11 through a circular shoulder or smoothly curved step 13, the lower surface 22 assuming a position lower than the centre plane X and being continuous to the lower wall 16 of the socket portion 11 in a smooth circular fashion.

A pair of upper ribs 30,30 are integrally formed between and over a longitudinal middle position on both widthwise sides of the upper surfaces 21 of the excavation portion 20 and positions on both widthwise sides at the extreme forward end of the upper wall 15 of the socket portion 11. An upper surface 30a of the upper rib 30 and the upper surface 21 of the excavation portion 20 are made to be continuous to each other at a predetermined angle a (a < 180 , and preferably 160 < a < 165 ) and being substan tialiy linearly continuous to the upper surface 15a of the socket portion 11.

It is noted that the size (width and height) of the pair of upper ribs 30,30 is the size to the extent that sufficient strength of the ripper point is obtained. For example, where the upper ribs 30,30 are increased in height, the extreme forward end of the upper wall 15 of the socket portion is made to be circular so that the upper ribs 30 may be increased in height.

Being arranged as described above, sufficient strength of the ripper tip can be obtained by the pair of ribs 30,30, and breakage hardly occurs during excavation.

The extreme forward end 20' of the excavation portion 20 has a flat rectangular shape without ribs 30, and therefore, the wall thickness t is not increased in case of wear, thus providing good excavatability.

It seems that in portions where the upper ribs 30 are provided, the wall thickness is increased to deteriorate the excavatability. However, the upper ribs 30 are provided, on both widthwise sides and the upper surface 30a is continuous to the upper surface 21 at a predetermined angle a, and therefore, the dug up rock flows along the upper surface 21 and the flowing direction of the rock is suddenly changed at the portion of angle a. Therefore, as shown in Figure 10, as the excavation portion 20 wears, the upper surface 30a of the upper rib 30 is gradually worn, and therefore the extreme forward end thereof is always maintained in wall thickness less then t to increase the excavatability.

Accordingly, the wall thickness of the worn portion is always maintained to be less than the wall thickness t of a centre portion, and the excavation portion can be used tiil the wear limit state while maintaining good excavatability, as shown in Figure 10.

That is, the excavation blade in accordance with the present invention can always maintain good excavatability until the wear limit state without involving abnormal wear as encountered in prior art.

As described above, the present invention provides an excavation blade which has a sufficient strengh and can be used till the wear limit state while maintaining good excavatability.

Claims (2)

1. A replaceable tip for an earth digging tooth, comprising: a rear tip portion having means for attachment to said tooth, said rear tip portion having top and bottom surfaces which are converging forwardly; a forward tip portion integrally formed with said rear tip portion and having top and bottom surfaces and side surfaces extending from said rear tip portion to a transverse forward edge of said tip, the top and bottom surfaces of said forward tip portion diverging rearwardly from the transverse forward edge of said tip and terminating in the top and bottom surfaces of said reartip portion, there being smoothly curved step formed transversely across the tip for connecting the top surfaces of said forward and rear tip portions; and a pair of ribs formed on the top surface of said forward tip portion at both lateral ends thereof, each rib being extending from the forward end of the top surface of said rear tip portion and terminating in an intermediate portion of the top surface of said forward tip portion.

2. A replaceable tip according to claim 1 wherein angle between the top surface of said forward tip portion and the top surface of each of said ribs if about 1600to about 165'.