GB2510433A

GB2510433A - Curved auger tooth and auger tooth holder

Info

Publication number: GB2510433A
Application number: GB201302045A
Authority: GB
Inventors: Alister Gordon Rayner
Original assignee: Attachment Torque MFG China Co Ltd
Current assignee: Attachment Torque MFG China Co Ltd
Priority date: 2013-02-05
Filing date: 2013-02-05
Publication date: 2014-08-06
Also published as: GB201302045D0; WO2014121745A1

Abstract

An auger tooth 20 has a tooth body 24, with a leading tooth edge 26, and a trailing tooth edge 28. The body has an outer longitudinal tooth edge 32, an inner longitudinal tooth edge 30 and a cutter 38 at the leading edge. The outer tooth edge curves from the leading edge in a rotational direction of the in use auger tooth. The cutter may be aligned with a radius of the curved outer edge, and there may be a curved rubbing strip 54 on the outer edge. The tooth body may have a U-shaped recess (48, figure 7) and a curved engagement portion 36 with two curved engagement arms 50 for inserting into a slot in an auger tooth holder (22, figure 5). A second invention includes auger tooth holder which has a curved tooth receiving recess. An auger tooth may be held in the holder by an engagement pin through an aperture 100.

Description

Auger Tooth The present invention relates to an auger tooth, and more particularly to a curved auger tooth curving in a plane including leading and trailing edges of the tooth, to an auger-tooth holder for holding such an auger tooth, and to a ground auger having a tooth carrier for carrying a plurality of said teeth.

Auger teeth are well known and for the present invention are for use with a ground auger. A ground auger comprises a vertical shaft which is rotatable by a drive mechanism, such as an engine, hydraulic unit or pneumatic unit, a tooth carrier which is fixed to a distal end of the shaft, and a helical flight which extends at least partway along the shaft from the tooth carrier. The auger teeth are typicaily releasably engagable with the tooth carrier, so as to be replaceable once worn.

The tooth carner typically has a radially-aligned leading edge, and the auger teeth are spaced apart along the leading edge, projecting at right angles therefrom. in this way, a cutter of the auger teeth is spaced from and parallel with the radially-aligned leading edge off the tooth calTier.

However, it has been found that the outside corner between the outer longitudinal edge of the auger tooth and the cutter is subject to greater wear than the remaining part of the cutter. When considering the radially outermost auger tooth on the tooth carrier in particular, this accolerated wear results in a reduction in the diameter of a hole being bored by the auger. This can be unacceptable in many cases, due to the diameter of the auger being specifically chosen to meet a diameter of a component to be inserted therein, such as foundations for piling or concrete, signage, fencing, telegraph and power poles, bollard, drainage, cabling, street furniture and the like.

The present invention seeks to provide a solution to this problem.

According to a first aspect of the invention, there is provided an auger tooth comprising a tooth body having a leading tooth edge, a trailing tooth edge, an outer longitudinal tooth edge and an inner longitudinal tooth edge, and a cutter at the leading tooth edge, the outer thngitudinal tooth edge curving from the leading tooth edge in a rotational direction of the in use auger tooth.

Preferable and/or optional features of the first aspect of the invention are set forth in claims ito 18. inclusive.

According to a second aspect of the invention, there is provided an auger-tooth holder comprising a holder body having a leading holder edge, a trailing holder edge, an outer longitudinal holder edge and an inner ongitudinal holder edge, and a curved-auger-tooth receiving recess which extends from the leading holder edge and curves towards the trailing holder edge in a rotational direction of the in use auger-tooth holder.

Preferable and/or optiona' features of the second aspect of the invention are set forth in claims 21 to 24, inclusive.

According to a third aspect of the invention, there is provided an auger-tooth assembly comprising an auger tooth according to the first aspect of the invention held by an auger-tooth holder in accordance with the second aspect of the invention.

IS According to a fourth aspect of the invention, there is provided a ground auger comprising a rotatable shaft, a tooth calTier rotatable by the rotatable shaft, and a plurality of auger teeth in accordance with the first aspect of the invention held by the tooth carrier, the cutter being radially aligned with the rotatable tooth carrier.

Preferably, the ground auger further comprises a plurality of auger-tooth holders in accordance with the second aspect of the invention on the tooth carrier, each auger-tooth holder engaging a said auger tooth with the tooth carrier.

According to a fifth aspect of the invention, there is provided a method of improving uniform wear of an auger tooth in accordance with the first aspect of the invention, the method comprising the steps of curving at least an outer longitudinal edge of the auger tooth in a rotational direction of the in use auger tooth, and orienting a cutter of the auger tooth so as to be perpendicular or substantially perpendicular to the rotational direction.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings. in which: Figure 1 shows an in use ground auger, in accordance with the fourth aspect of the invention and shown connected to a drive unit attached to an articulated arm of an excavator; Figure 2 shows the ground auger having a shaft, flight along the shaft and a tooth carrier mounted at or adjacent to one end for carrying a plurality of auger teeth, in accordance with the invention; Figure 3 shows a plan view of an auger tooth, in accordance with the first aspect of the invention; Figure 4 shows a side elevational view of the auger tooth; Figure 5 shows a plan view of an auger-tooth holder, in accordance with the second aspect of the invention; Figure 6 shows a side elevational view of the auger-tooth holder; Figure 7 shows a plan view of the auger tooth and auger-tooth holder, in spaced apart relationship; and Figure 8 shows a plan view of the auger tooth engaged with the auger-tooth holder.

Referring to the drawings, there is shown an auger-tooth assembly 10 for a ground augcr 12. Thc tcrm ground auger' used herein and throughout mcans an auger which is drivable by a machine with hydraulics such as an Excavator or machine with a PTO such as a Tractor, an internal combustion engine, and which is suitable for forming holes, typically being cylindrical, in earth. A ground auger may also be known as an earth drill' or auger. Preferably, the ground auger i2 is releasably attachable to a, typically articulated, arm 14 and/or hitching point 16 of an excavator 18, backhoe, skid steer loader, mini loader. digger. drill rig, truck crane, tele-handler, tractor or tool carrier.

The auger-tooth assembly 10 comprises an auger tooth 20 and an auger-tooth holder 22 which holds the auger tooth 20. The auger tooth 20 includes a tooth body 24 having a leading tooth edge 26, a trailing tooth edge 28, an inner longitudinal tooth edge 30 and an outer longitudinal tooth edge 32, which together define a holder-projecting portion 34, and a holder-engagement portion 36 which extends from the holder-projecting portion 34 and which is cngagablc with thc augcr-tooth h&dcr 22. Thc holdcr-projecting portion 34 terminates with the leading tooth edge 26, and the holder-engagement portion 36 terminates with the trailing tooth edge 28.

In this embodiment, the tooth body 24 is substantially planar or fiat, whereby the leading tooth edge 26, trailing tooth edge 28 and inner and outer longitudinal tooth edges 30, 32 all lie in at least substantially the same plane.

A cutter 38 is provided at the leading tooth edge 26, and this may be in the form of a row of carbide or hardened teeth aligned to extend along the leading tooth edge 26. The cutter 38 may, however, simply be a hardened cutting edge formed at the leading tooth IS edge 26. In the present case, the cutter 38 is formed as a hardened ramped surface on the leading tooth edge 26. The upper ramped surface 40 of the cutter 38 has a greater pitch on an upper sm-face 42 of the tooth body 24, and the lower ramped surface 44 of the cutter 38 has a lesser pitch on a lower surface 46 of the tooth body 24. The lower ramped surface 44 extends in a direction of the trailing tooth edge 28 of the tooth body 24 a greater distance than the upper ramped surface 40, thereby drawing the in use auger 12 into the earth during a cutting process.

The trailing tooth edge 28 defines a slot-like recess 48, in this case being U-shaped, for releasably engaging the auger-tooth holder 22. Two engagement arms 50 are defined by the recess 48 and the inner and outer longitudinal tooth edges 30. 32, respectively. The two engagement arms 50 extend in parallel with each other and are, preferably slidably, receivable by the auger-tooth holder 22. Although a slot-like recess 48 is preferred, a single tongue may be provided for receipt into a slot within an auger-tooth holder.

To prevent or reduce uneven wear at the cutter 38 and/or leading tooth edge 26, the tooth body 24 is at least in part curved in a rotational direction R of the in use auger tooth 20. In this case, both the inner and outer longitudinal tooth edges 30, 32 are curved along their entire longitudina' extents. The lateral extents of the inner and outer longitudinal tooth edges 30, 32 may be arcuate or flat.

The radius of curvature of the inner and outer longitudinal tooth edges 30, 32 preferably matches or substantially matches a radius of the auger 12 with which the auger tooth 20 will be used.

Furthermore, the cutter 38 and/or the leading tooth edge 26 is/are aligned with a radius of the curve of the outer longitudinal tooth edge 32.

By curving the outer longitudinal tooth edge 32, especially for an outermost auger tooth 20, wear at the corner 52 between the leading tooth edge 26 and the outer longitudinal tooth edge 32 is reduced. Additionally, by providing the cutter 38 and/or leading tooth edge 26 so as to be on or substantially on a turning radius of the in use auger 12, the cutter 38 evenly or substantially evenly meets the material being drilled or cored, thereby enabling a more even or uniform wear rate across the entire cutter 38 and/or leading tooth edge 26.

To accommodate frictional wear along the outer longitudinal tooth edge 32 whilst the auger tooth 20 is in use, a rubbing strip 54 is provided which extends along the outer longitudinal tooth edge 32 from the eading tooth edge 26 to the trailing end 56 of the holder-projecting portion 34. The rubbing stnp 54 is preferably arcuate, extending in parallel with the outer longitudinal tooth edge 32. Beneficially, the rubbing strip 54 has a uniform or substantially uniform lateral extent in two mutually perpendicular directions along at least a majority of its length. In other words, the rubbing strip 54 has an at least substantially constant width in a radial direction X of the auger tooth 20, and preferably also a substantially constant depth in an axial direction Y of the auger tooth 20.

A leading end 58 of the rubbing strip 54 is profiled to match the leading tooth edge 26 and the cutter 38 may extend onto the rubbing strip 54. A trailing end 60 of the rubbing strip 54 may slant in a top to bottom direction, and this is beneficial in guiding material axially upwards when the auger tooth 20 is in use. The trailing end 60 thus forms a step 61 to meet the outer longitudinal tooth edge 32 as it extends onto the holder-engagement portion 36 of the auger tooth 20.

In this embodiment, the holder-projecting portion 34 of the tooth body 24 and the holder-engagement portion 36 are curved, whereby the leading tooth edge 26 andlor cutter 38 extends at or substantially at right angles to the inner and outer longitudinal tooth edges 30, 32, and the engagement arms 50 curve in parallel with each other.

The slot-like recess 48 of the holder-engagement portion 36 includes a mounting face 62 for a shock-absorbing element, preferably being a rubber strip. The mounting face 62 extends from or adjacent to a rearmost face 64 of the trailing tooth edge 28, and around an inner face 66 of the slot-like recess 48. A lateral extent of the mounting face 62 includes upper and lower ramped surfaces 68 to provide an elongate apex 72 which faces into the opening defined by the slot-like recess 48. The shock-absorbing element is U-shaped, havthg an outer mounting surface which is complementarily shaped, in this case including a V-shaped recess in its lateral extent, to match the mounting face 62 of IS the s'ot-like recess 48. An inner contact surface of the shock-absorbing element provides for abutment with the auger-tooth holder 22.

Dunng an impact of the cutter 38 of the auger tooth 20, a compressive force extending perpendicularly from the leading tooth edge 26 tends to urge the auger tooth 20 towards the auger-tooth holder 22. With the shock-absorbing element extending around a majority of the longitudinal extent of the s'ot-like recess 48, the shock-absorbing element is sandwiched between the auger tooth 20 and the auger-tooth holder 22. The compressive force in the plane of the auger tooth 20 urges the forwardmost pordon of the shock-absorbing element into contact with the auger-tooth holder 22, thus dissipating shock energy.

To retain the auger tooth 20 with the auger-tooth holder 22, an elongate pin slot 74 is provided adjacent to a distal end of one of the engagement arms 50. Only one pin slot 74 need be provided, but a further pin slot can be provided on the other engagement arm 50, if required.

Although the auger tooth 20 is substantially planar, it may also be curved in the axial direction Y of the in use auger 12, if required.

The inner longitudinal tooth edge 30 need not be curved, and may in fact be straight.

The outer longitudinal tooth edge 32 may iiot be curved along its entire extent. To this end, the portion of the outer longitudinal tooth edge 32 extending form the leading tooth edge 26 and along the holder-projecting portion 34 is curved. The portion of the outer longitudinal tooth edge 32 extending along the holder-engagement portion 36 may not be curved and thus may be straight, dependent on the auger-tooth holder 22 utilised.

The auger-tooth holder 22 is complimentarily shaped to receive the auger tooth 20, in this case, as a close sliding fit. k this embodiment, the auger-tooth holder 22 comprises a holder body 76 having a leading holder edge 78, a trailing holder edge 80, an inner longitudinal holder edge 82 and an outer longitudina' holder edge 84. A curved-auger-tooth receiving recess 86 extends from the leading holder edge 78 and curves towards the trailing holder edge 80 in a rotational direction R of the in use auger-tooth holder 22.

The curved-auger-tooth receiving recess 86 defines a channel 88 having an upper surface 90 and a lower surface 92. An interior wall 94 extending centrally of the holder body 76 provides an inner surface of the channel 88. The interior wall 94 preferably terniinates before the leading holder edge 78.

The channel 88 is thus adapted to slidably receive the trafling tooth edge 28 of the auger tooth 20, so that it is sandwiched between the upper and lower surfaces 90, 92. The interior wall 94 is receivable in the slot-like recess 48 of the auger tooth 20, and the leading portion 96 of the interior wall 94 abuts the shock-absorbing dement at the forwardmost portion of the slot-like recess 48.

Preferably, the interior wall 94 itself includes an elongate recess 98 extending therearound for receiving a projecting portion of the shock-absorbing element carried by the auger tooth 20.

A pin aperture 100 is formed through the holder body 76, so as to coincide with the elongate pin slot 74 of the auger tooth 20. With the engagement arms 50 of the auger tooth 20 slid home into the channel 88 of the auger-tooth holder 22. an engagement pin can be inserted through the pin aperture 100. The engagement pin thus locates in the pin slot 74. preventing separation of the auger tooth 20 from the auger-tooth hoMer 22. The elongation of the pin slot 74 allows restricted slidable movement of the auger tooth 20 in the channel 88 of the auger-tooth holder 22 for shock absorbing purposes, whilst the engagement pin remains in situ. Alternatively, this could also be achieved by fixing an engagement pin into the tooth with a slot then being in the tooth holder.

As with the auger tooth 20, at least the outer longitudinal holder edge 84 is curved. In this case, the inner longitudinal holder edge 82 is also curved. The curvatures of the inner and outer longitudinal holder edges 82, 84 match or substantially match the curvatures of the inner and outer longitudinal tooth edges 30, 32, respectively.

Furthermore, the inner and outer longitudinal tooth edges 30, 32 are preferably flush with the inner and outer longitudinal holder edges 82, 84, respectively.

The inner and outer longitudinal holder edges 82, 84 preferably curve from the leading holder edge 78. As with the auger tooth 20, the auger-tooth holder 22 may define a tooth-receiving portion 102 which extends from the leading holder edge 78, and a carrier-mounting portion 104 which extends from a trailing end 106 of the tooth-receiving portion 102. The inner and outer longitudinal holder edges 82, 84 preferably curve in the rotational direction R of the auger-tooth holder 22 along at least the tooth-receiving portion 102.

Due to the longitudinal extent of the slot-like recess 48 of the auger tooth 20 curving, the interior wall 94 and the channel 88 also complimentarily curve.

The curvature of the auger-tooth holder 22 is beneficial, enabling correct orientation of the auger tooth 20. However, as mentioned above, it is feasible that the holder-engagement portion 36 of the auger tooth 20 may be linear rather than crnved, and as such the auger-tooth holder 22 in this case would also have a linear tooth-receiving portion 102 defining a channel 88 which was straight in a leading holder edge to trailing holder edge direction.

The curved-auger-tooth receiving recess 86 in this case extends in a plane which includes the leading holder edge 78. The recess 86 curves in the said p'ane in a rotational direction R of the in use auger 12 in order to accommodate the curved auger tooth 20. If the curved auger tooth 20 is also curved in an axial direction Y as well as the above-described rotational direction R, then the tooth-receiving portion 102 of the auger-tooth holder 22 would bc cornplcrncntarfly shapcd. In this way, thc auger tooth 20 and the auger-tooth holder 22 may be curved in two mutually perpendicular directions.

The carrier-mounting portion 104 of the auger-tooth holder 22 is held by a tooth carrier 108 of the ground auger 12. Typically, the tooth carrier 108 may be a plate, casting, forging or other rigid and robust support dement which extends to or substantially to the required diameter of the auger 12 and the flights 110 thereon, and is fastened to an auger shaft 112 coimectable to a dnve unit 114. The shaft 112 may include an earth guide 116 which projects axially below the tooth carrier 108.

The carrier-mounting portion 104 of each auger-tooth holder 22 is welded or otherwise IS fastened to the tooth carrier 108 at spaced apart intervals along the diameter. A eading tooth edge 26 of the tooth carrier 108 preferably coincides with a radius of the auger 12, and the curvature of the auger tooth 20, particularly of the radially outermost auger tooth 20 a'igns a radial extent of the cutter 38 with the turning radius.

It is thus possible to provide an auger tooth having more uniform wear characteristics at its eading edge and on its cutter, thereby improving the longevity of the auger tooth.

Due to the improved wear characteristics, such an auger tooth applied to an auger-tooth assembly and to a ground auger allows improved coring and drilling diameter accuracy over multiple drilling processes. The curved auger tooth with complimentarily curved auger-tooth holder also prevents or limits the possibility of inserting the auger tooth in an inverted or upside down manner.

The embodiments described above are provided by way of examples only, and further modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined by the appended claims.

Claims

Claims 1. An auger tooth comprising a tooth body having a leading tooth edge, a trailing tooth edge, an outer longitudinal tooth edge and an inner longitudinal tooth edge, and a cutter at the leading tooth edge, the outer longitudinal tooth edge curving from the leading tooth edge in a rotational direction of the in use auger tooth.
2. An auger tooth as claimed in claim 1, wherein the cutter is aligned with a radius of the curve of the outer longitudinal tooth edge.
3. An auger tooth as claimed in claim I or claim 2, wherein the outer longitudinal tooth edge is curved along at least a majority of its longitudinal extent.
4. An auger tooth as claimed in any one of the preceding claims, wherein the outer longitudinal tooth edge is curved along its entire longitudinal extent.
5. An auger tooth as claimed in any one of the preceding claims, further comprising a rubbing strip on the outer longitudinal tooth edge.
6. An auger tooth as claimed in dairn 5. wherein the rubbing strip has a uniform or substantially uniform lateral extent along at least a majority of its length.
7. An auger tooth as claimed in dairn 5 or claim 6, wherein a longitudinal extent of the rubbing strip is curved.
8. An auger tooth as claimed in any one of claims 5 to 7, wherein the cutter extends onto a leading tooth edge of the rubbing strip.
9. An auger tooth as claimed any one of claims S to 8, wherein the rubbing strip extends partway along the outer longitudinal tooth edge.
10. An auger tooth as claimed in claim 9, wherein a trailing tooth edge of the rubbing strip forms a step to meet the outer longitudinal tooth edge.
11. An auger tooth as daimed in any one of the preceding claims, wherein the tooth body is at least in part curved.
12. An auger tooth as dairned in any one of the preceding claims, wherein the tooth body indudes a holder-projecting portion having the leading tooth edge and a holder-engagement portion which extends from the holder-projecting portion and which is engagable with an auger-tooth holder, the inner and outer longitudinal tooth edges at the holder-projecting portion being curved.
13. An auger tooth as claimed in claim 12, wherein the cutter extends at right angles or substantially at right angles to the inner and outer longitudinal tooth edges.
14. An auger tooth as claimed in claim 12 or claim 13, wherein the inner and outer longitudinal tooth edges at the holder-engagement portion are curved.
15. An auger tooth as claimed in any one of claims 12 to 14, wherein the holder-engagement portion is curved.
16. An auger tooth as claimed in any one of the preceding claims, wherein the cutter extends across the entire leading tooth edge of the tooth body.
17. An auger tooth as claimed in any one of the preceding claims, wherein the trailing tooth edge defines a U-shaped recess for releasable engagement with an auger-tooth holder.
18. An auger tooth as claimed in any one of the preceding claims, wherein the tooth body includes two curved engagement arms for releasable engagement with an auger-tooth holder.
1 9. An auger tooth substantially as hereinbefore described with reference to Figures 3,4,7 and 8 of the accompanying drawings.
20. An auger-tooth holder comprising a holder body having a leading holder edge, a trailing holder edge, an outer longitudinal holder edge and an inner longitudinal holder edge, and a curved-auger-tooth receiving recess which extends from the leading holder edge and curves towards the trailing holder edge in a rotational direction of the in use auger-tooth holder.
21. An auger-tooth holder as claimed in claim 20, wherein the outer longitudinal holder edge extending from the leading holder edge being curved.
22. An auger-tooth holder as claimed in claim 21, wherein the outer longitudinal holder edge curves to or adjacent to a trailing end of the recess.
23. An auger-tooth holder as claimed in claim 22, wherein the recess extends in a plane which includes the leading holder edge, the recess curving in said plane.
24. An auger-tooth holder as claimed in any one of claims 20 to 23, wherein the recess defines a channel having an upper surface and a lower surface, a trailing edge of the auger tooth being receivable in the channel between the upper and lower surfaces.
25. An auger-tooth holder substantially as hereinbefore described with reference to Figures 5 to 8 of the accompanying drawings.
26. An auger-tooth assembly comprising an auger tooth as claimed in any one of claims Ito 19 held by an auger-tooth holder as claimed in any one of claims 20 to 25.
27. A ground auger comprising a rotatable shaft, a tooth carrier rotatable by the rotatable shaft, and a p'urality of auger teeth as claimed in any one of claims I to 19 held by the tooth carrier, the cutter being radially aligned with the rotatable tooth carrier.
28. A ground auger as claimed in claim 27, further comprising a plurality of auger- tooth holders as claimed in my one of claims 20 to 25 on the tooth carrier, each auger-tooth holder engaging a said auger tooth with the tooth carrier.
29. A method of improving uniform wear of an auger tooth as claimed in any one of claims I to 19, the method comprising the steps of curving at least an outer longitudinal edge of the auger tooth in a rotational direction of the in use auger tooth, and orienting a cutter of the auger tooth so as to be perpendicular or substantially perpendicular to the rotational direction.