GB2251641A

GB2251641A - Excavator shovel or bucket

Info

Publication number: GB2251641A
Application number: GB9200757A
Authority: GB
Inventors: Sven Ree
Original assignee: KVERNEX AS
Current assignee: KVERNEX AS
Priority date: 1991-01-14
Filing date: 1992-01-14
Publication date: 1992-07-15
Anticipated expiration: 2012-01-14
Also published as: GB9200757D0; FI920113A0; GB2251641B; NO910141L; NO171605B; FI920113A; NO910141D0; NO171605C; SE9200037D0; DE4200695A1; SE9200037L

Abstract

Excavator shovel or bucket comprises a number of detachably mounted digging teeth (1), whereby each tooth may be rotated so that an inactive tooth edge (1'') may be brought into an active position. The digging tooth (1) is formed with one single, centrally positioned, anchor hole (2) for fastening to the top or bottom side of a shovel or bucket front piece (5). The top or bottom face of the digging tooth (1) is formed with an engagement means of the pin/hole type (6, 6') equidistant from the centre of the anchor hole (2), said engagement means being formed for easily releasable engagement with a complementary engagement means (7) of the shovel or bucket front piece (5). <IMAGE>

Description

-. 1 - IMPROVEMENTS RELATING TO DIGGING TEETH 2231641 The present

invention relates to the bucket or shovel of earth-moving machinery, in particular to digging teeth detachably mounted on the bucket or shovel of earth-moving machinery where each tooth is of an elongated shape with both ends being formed as digging edges. The digging tooth is provided with a hole for the purpose of attaching it to the overside or underside of the bucket front part by means of a bolt, whereby the tooth may be detached and rotated in order to engage an unused tooth edge.

Such digging teeth presently available are formed generally symmetrically in relation to two mutually perpendicular central axes; the top and bottom faces, however. having different designs. A larger longitudinal surface portion of the tooth top or bottom face will, upon attachment. rest against the top or bottom face of the front piece of the digging shovel. According to the prior art. the tooth is generally attached to the bucket or shovel by two anchor bolts located along the longitudinal central axis of the tooth. and equidistant from the lateral central axis.

The turning of such known digging teeth is laborious, this being due to the fact that both anchor bolts have to be removed, whereafter the bolts have to be positioned and tightened once the tooth has been turned or replaced.

reIt is not possible with this form of digging tooth to turn the tooth about one anchor bolt, because the tooth is not symmetrical with respect to either of the anchor holes.

By using two anchor bolts for each prior art digging tooth, there will be a certain distance between the two anchor holes. This intermediate portion between the two anchor holes of the tooth represents substantial material costs.

1 The pr-es6nt invention provides digging teeth, which reduce the quantity of- material required for their manufacture whilst maintaining adequate strength and achieving simplified attachment and turning, and a shovel or bucket designed in order to enable simplified attachment of the digging teeth.

According to the present invention there is provided an excavator bucket or shovel having a leading edge provided with a plurality of digging teeth releasably mounted on said edge, each tooth having opposed digging or cutting edges and being mounted with one tooth edge. comprising a working edge. located forwardly of said leading edge and a further tooth edge located inboard of said leading edge; in which each tooth has a mounting hole located midregion between the tooth edges through which a fastener can be taken in order to mount the tooth on said leading edge. said tooth being rotatable upon slackening the fastener in order to bring an inboard tooth edge to the point previously occupied by the working edge.

Preferably, each digging tooth may have two axially opposite ends acting as digging edges and a central anchor hole enabling the tooth to be releasably rotated between two diametrically opposed positions. In an operative or digging position the tooth protrudes or extends beyond the edge of the excavator bucket or shovel- The top or bottom face of the tooth may have at least one protrusion engageable with a corresponding recess on the bucket or shovel. At each tooth attachment place the excavator bucket or shovel may be formed with only one anchor hole for the anchor bolt and a short protruding guide means, which is formed to engage into one of the corresponding shallow recesses of the digging tooth. The anchor hole is spaced inwandly in relation to the front edge of the bucket or shovel front piece. A digging tooth of the kind concerned is formed with..only one central anchor hole for an anchor bolt and-, at both sides of the anchor hole. equidistant from the centre. a-sh.allow blind bore and 1 or countersinking to engage a'-short protrusion or guide means on the front piece of the digging bucket or shovel. The protrusion or guide means may take the form of a bolt or stud.

The top or bottom face of the tooth may have a plurality of protrusions spaced equidistant from the central anchor hole and with at least one protrusion engageable with a recess on the bucket or shovel.

It is evident that instead of the attachment arrangement described above, the top or bottom face of the tooth may have at least one recess engageable with a corresponding protrusion on the bucket or shovel.

Also, the top or bottom face of the tooth may have a plurality of recesses spaced equidistant from the central anchor hole and with at least one recess engageable with a protrusion on the bucket or shovel.

It is also evident that the digging tooth may be secured to either the top or bottom side of the shovel or bucket front piece.

The protruding guide means merely necessitates a very shallow recess. resulting in a negligible weakening of the tooth. However the protruding guide means prevents the digging tooth from rotating around the anchor bolt when being subjected to loads placed on the tooth during the digging operation.

When the operative end of the digging tooth becomes worn, the anchor bolt is loosened to such an extent that the digging tooth may be pulled out from the front piece of the shovel or bucket until the space between the tooth and the front piece exceeds the engagement depth of the protruding guide means into the corresponding recess of the tooth. Thereafter, the tooth may be rotated using the partly screwed-out anchor bolt as a pivot until an unworn or unused end protrudes from the bucket or shovel front piece and forms the new digging tooth edge. The anchor bolt is then re-tightened locking the tooth in position. When all of the digging tooth ends have been worn. the tooth as a whole must be replaced by a new one.

The technical effect obtained by means of the invention, consists mainly in a simplification of the digging tooth attachment, turning and replacement. Therefore. these working operations may be carried out more rapidly and with less labour than previously required with presently available digging teeth. Moreover, a substantial material saving may be achieved, by an optimal utilization of the material of the tooth body. Only a small area around the single anchor hole in the tooth is unused, resulting in minimum consumption of material.

The number of anchor bolts is reduced compared to configurations of digging teeth presently available. production costs for such bolts are relatively and, therefore, a reduction of the number of bolts represents a substantial material saving for the producer and. consequently a reduced price to the user.

known The substantial A digging tooth according to the invention will be simpler and therefore cheaper to cast. forge. heat treat and machine than digging teeth presently available. This is partly because given tolerances between the spacing of two anchor holes are not required.

As a result of the material savings a digging tooth according to the invention is lighter and easier to handle than corresponding prior art digging teeth. The digging tooth of the present invention has as much wearing material as known digging teeth and, therefore. a working or service life as lofig as the latter.

It should be pointed out that a digging tooth according to the invention is advantageous with regard to resources as well as to the environment, because it requires less material and. therefore. less heating both for the manufacturing of the steel and for the making of the tooth than for the production of known digging teeth.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which; Figure 1 shows a cross-sectional view through the longitudinal central plane of a digging tooth and through the adjacent attachment portion of an excavator shovel or bucket. the remaining portion thereof not being shown. the tooth being mounted to said shovel's front piece; Figure 2 shows a perspective view of a digging tooth separately, as seen obliquely from above, in order to illustrate the special design of the top face of the tooth.

In the figures, a digging tooth generally indicated by 1. has a centrally positioned anchor hole 2 for an anchor bolt 3 adapted to be screwed into a threaded bore 4 in a front piece 5 of an excavator's bucket or shovel. As is well known. the digger shovel has a number of attachment points for such digging teeth 1.

The design of the anchor bolt 3 is not critical for the present invention: in the embodiment shown the bolt 3 has a fixed nut-shaped head 3'. a conical transition portion 3--and a treated bolt shank 3---.

The anchor hole,2 of the tooth 1 is shaped complementary to the anchor bolt and comprises a conical transition portion 2' and a smooth bore section 2", through which the upper portion of the threaded bolt shank 3--extends.

Due to the loads and forces to which the bottom of the shovel or bucket is subjected during digging. it is advantageous not to have parts such as nut or bolt heads protruding therefrom. In principle, however, nothing would prevent the use of other bolt types, pin screws and the like for the attachment of the teeth 1 onto the digger shovel 5 other than the screw bolt shown. The latter. however represents a preferred choice of attachment means for the mounting in question.

At each side of the central anchor hole 2 of the tooth 1. the bottom face of the tooth is formed with a relatively shallow recess, blind bore or cavity 6 and 6'. positioned on the longitudinal symmetry axis of the tooth 1 and equidistant from the centre of the anchor hole 2. In the assembled state of the tooth 1, the innermost recess 6' will cooperate with a protruding guide or stop means, here shown in the form of a bolt 7 screwed into a threaded hole 8 in the shovel front piece 5, so that a releasable engagement between the means 7 and the recess is established. The engagement is sufficient to prevent rotation of the tooth 1 around the anchor bolt 3 when the tooth is subjected to loads during digging.

The digging tooth has two axially opposed ends 1 and 1" constituting the actual digging means or portions. When one end, for example 1', has become worn, the anchor bolt 3 is slackened until the tooth 1 may be pulled out from the adjacent shovel front piece until the tooth bottom'face can be spaced from the top face of the front piece 5 a distance slightly exceeding the engagement depth of the stop or guide means 7 into the recess 6' of the tooth. Thereafter, the tooth 1 may be rotated 180 around the centrally positioned anchor bolt 3, the digging end portion 1" taking an operative position and.,-the recess 6 being brought into engagement with the means 7_; so that the position of the tooth is retained when the-anchor bolt 3 is re-tightened.

The tooth design shown in Figure 2 exhibits a central annular portion la, within which the tooth has its maximum thickness. From the annular portion la. the tooth top face slopes toward each of the two axial ends 1' and V', more specifically with longitudinal, uniformly extending lateral limitation portions 1b which. in pairs. define longitudinal uniformly extending portions or cavities lc.

Upon 180 rotation of a single tooth 1 attached to an excavator bucket or shovel where the teeth are positioned relatively close to each other, it might be necessary to unscrew the anchor bolt 3 completely prior to rotating the tooth.

However. the particular shape of the tooth 1 is not critical for the achievement of the primary object of the invention and may. therefore, be subject to modifications within the scope of the invention.

The tooth position locking effect performed by means of the stop or guide bolt's 7 engagement into one of the recesses 6 or 6' of the tooth 1, in combination with the anchor bolt 3 may, of course, also be obtained through the opposite positioning of the engagement means 6. 6' and 7. The tooth 1 may be equipped with short protruding engagement means corresponding to the stop or guide bolt 7, namely at the shown positions of the recesses 6 and 6'. The shovel front piece 5 would be formed with a recess at the shown position of the stop or guide 7 corresponding to the recesses 6 and 6' of the tooth according to Figure 1.

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Claims

CLAIMS:

An excavator bucket or shovel having a leading edge provided with a plurality of digging teeth releasably mounted on said edge. each tooth having opposed digging or cutting edges and being mounted with one tooth edge. comprising a working edge, located forwardly of said leading edge and a further tooth edge located inboard of said leading edge; in which each tooth has a mounting hole located mid-region between the tooth edges through which a fastener can be taken in order to mount the tooth on said leading edge, said tooth being rotatable upon slackening the fastener in order to bring an inboard tooth edge to the point previously occupied by the working edge.
2. An excavator bucket or shovel as claimed in claim 1 in which the tooth is elongated having two axially opposite ends acting as digging edges and a central anchor hole enabling the tooth to be releasably rotated between two diametrically opposed positions.
3. An excavator bucket or shovel as claimed in claims 1 or 2 in which the top or bottom face of the tooth has at least one protrusion engageable with a corresponding recess on the bucket or shovel.
4. An excavator bucket or shovel as claimed in claims 1 or 2 in which the top or bottom face of the tooth has a plurality of protrusions spaced equidistant from the central anchor hole and with at least one protrusion engageable with a recess on the bucket or shovel.
5. An excavator bucket or shovel as claimed in claims 1 or 2 in which the top or bottom face of the tooth has at least one recess-engageable with a corresponding protrusion on the bucket or shovel-
6. An excavator bucket or shovel as claimed in claims 1 or 2 in which the top or bottom face of the tooth has a plurality of recesses spaced equidistant from the central anchor hole and with at least one recess engageable with a protrusion on the bucket or shovel.
7. An excavator which has fitted to it a bucket or shovel as claimed in any one of claims 1 to 7.