CA1069962A - Digger tooth retainer - Google Patents
Digger tooth retainerInfo
- Publication number
- CA1069962A CA1069962A CA322,641A CA322641A CA1069962A CA 1069962 A CA1069962 A CA 1069962A CA 322641 A CA322641 A CA 322641A CA 1069962 A CA1069962 A CA 1069962A
- Authority
- CA
- Canada
- Prior art keywords
- shank
- retaining means
- recess
- tooth
- retainer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Component Parts Of Construction Machinery (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Means adapted for retaining a shank in a recess. The retaining means comprises a resilient collar having an inner surface adapted for co-acting with the shank and a peripheral surface adapted for co-acting with the walls of the recess. The peripheral surface is eccentrically displaced with respect to the inner surface. The inner surface of the retaining means, and a co-acting surface of the shank, have complementary regular polygonal shapes.
Means adapted for retaining a shank in a recess. The retaining means comprises a resilient collar having an inner surface adapted for co-acting with the shank and a peripheral surface adapted for co-acting with the walls of the recess. The peripheral surface is eccentrically displaced with respect to the inner surface. The inner surface of the retaining means, and a co-acting surface of the shank, have complementary regular polygonal shapes.
Description
Z
This is a di~isional a~plication of application serial number 253,465, This invention relates to resilient means adapted for retaining a shank in a recess.
Digger teeth of the type comprising an excavating portion and a bifurcated shank portion adapted for co-acting with a digger tooth holder are well known in the art. Resilient means for retaining a digger tooth in a digger tooth holder are also well known. With the presently available type of resilient retaining means and teeth, the holding force between a particular tooth and the holder is established at the factory and hence any stretch or wea~ on the resilient retainèr or holder cannot be compensated for in the field. Further, a retainer, such as disclosed in United States Patent -
This is a di~isional a~plication of application serial number 253,465, This invention relates to resilient means adapted for retaining a shank in a recess.
Digger teeth of the type comprising an excavating portion and a bifurcated shank portion adapted for co-acting with a digger tooth holder are well known in the art. Resilient means for retaining a digger tooth in a digger tooth holder are also well known. With the presently available type of resilient retaining means and teeth, the holding force between a particular tooth and the holder is established at the factory and hence any stretch or wea~ on the resilient retainèr or holder cannot be compensated for in the field. Further, a retainer, such as disclosed in United States Patent -
2,96~,880, allows the tooth to pivot in the holder so that its shanks are subjected to dynamic shock loading when irregular material is being excavated.
Accordin~ to the present invention there is provided a digger tooth retaining means for retaining a shank of a digger tooth in a recess of a holder; said retaining means ccmprising a resilient collar having an inner surface of a shape complementary to an exterior surface of said shank and a peripheral surfaceen~ageakle with the walls of said recess; said peripheral surace being eccentrically displaced with respect to said inner surface;
the inner surace of the retaining means, and a co-acting surface of the shank, `
haYing complementary regular polygonal shapes, whereby the retaining means can be rotated relative to the shank, such that the region of maximum thickness and surface eccentricity of the retaining means can be changed to compensate for wear between the shank and the wall of recess.
In a preferred construction the inner surfaces of the retaining means are relieved by a radial groove to allow for material displacement in - 1 - ~
,~.~, .
the retaining means during insertion of the shank into the recess.
For exampleg the relief means may comprise a recess in the inner surface of the retaining means at the region of maximum thickness and surface eccentricity of the retaining means; the lateral extent of the recess means being generally equal to a side of the polygonal shape.
The retaining means can be rotated relative to the shank, such that the re~ion o~ maximum thickness and surface eccentricity of the retaining means can be changed to compensate for wear and dimensional variations between the shank and walls of the recess.
Rotation of the resilient retainer collar and thus a change in the angular position of the wall surface eccentricity effects adjustment of the retaining force allowing in-field compensation for stretch, wear, and dimen-sional variants between the shank and the recess. This adjustment allows a preloading of a digger tooth so ~hat there is a gradual increase in load as opposed to the shock load that is encountered using conventional retainers.
Digger teeth using a resilient retainer according to the invention are economical to produce since large manufacturing tolerances can be compen-sated for by the retainer. The holders are economical to produce and use in that no holes are required to accommodate the retainers and large manufactur-ing tolerances can be compensated for. Economical field operations are pos-sible in that, with each new tooth, a new retainer is supplied and wear variations between holders can be compensated for readily.
The relieving of the inner surface of the retainer allows for the displacement of the resilient material during insertion of the shank into the recess. It is preferred that the width of the relief notch equals the length of one side of the polygonal portion of the shank and that it be located at the point of maximum eccentricity and wall thickness of the -;, . ~ , , , " , , ,, ; ,:
~ 6~g~ ~
retainer. This is so that, under compression of the retainer, a vertical as well as a horizontal holding force is generated.
When the resilient retainer is employed on a digger tooth of the type described, compensation for stretch in the digger tooth holder is made - 2a -iA
" , ; ., , . , , " :,- ................... . .
' ' : . '.'' . , .: . , '' ,,;: '"' . ,' ' :' :~':,:'". ' ,., ' ' '' ': ', '. ' ': , , ,: ;:.. , -., ''': ,-, ~0~9~62 by rotating the retainer relative to the digger tooth so that the maximum eccentricity of the retainer is in alignment with the maximum stretch on the holder. The retaining force generated has a component directed toward the center of the tooth as well as a component in the direction of the maximum stre~ch. The force component in the direction of stretch preloads the tooth so that5 when excavating force reversal occurs, there is a gradual build up on the tooth and retainer.
In drawings which illustrate embodiments of the invention which should not be taken as limiting the scope of the invention, Figure 1 shows an exploded assembly of a digger tooth and holder, Figure 2 shows a tooth in plan view, Figure 3 shows section 9-9 of the tooth of Figure 2, Figure 4 shows an enlarged end viel~ of a retainer, Figure 4a shows another retainer installed on a tooth, Figure 5 shows a retainer as instaLled in a holder that is neither worn nor stretched and as viewed through a section equivalent to section 9-9 of Figure 2, J Figure 6 shows a retainer as installed in a worn recess~Referring to Figure 1, a digger tooth 4 comprises a tip portion 24, adapted for excavating and a shank portion comprising two shanks 3, separated by a rectangular slot 25, and adapted for insertion into a holder 1. The holder 1 comprises a central portion 23 incorporating two recesses 2, one of which is shown. Each shank 3 is receivable in one of the recesses 2. Collar-shaped retainers 5 are adapted to fit an octagonal portion 6 on the shanks 3. The portions 7 on the shanks 3 have substantially circular cross-sections and serve to prevent axial displacement of the retainers 5 from the shanks 3 during removal of the tooth from the holder. Complemen-tary octagonal holes 8 are provided in the retainers 5 so that each retainer
Accordin~ to the present invention there is provided a digger tooth retaining means for retaining a shank of a digger tooth in a recess of a holder; said retaining means ccmprising a resilient collar having an inner surface of a shape complementary to an exterior surface of said shank and a peripheral surfaceen~ageakle with the walls of said recess; said peripheral surace being eccentrically displaced with respect to said inner surface;
the inner surace of the retaining means, and a co-acting surface of the shank, `
haYing complementary regular polygonal shapes, whereby the retaining means can be rotated relative to the shank, such that the region of maximum thickness and surface eccentricity of the retaining means can be changed to compensate for wear between the shank and the wall of recess.
In a preferred construction the inner surfaces of the retaining means are relieved by a radial groove to allow for material displacement in - 1 - ~
,~.~, .
the retaining means during insertion of the shank into the recess.
For exampleg the relief means may comprise a recess in the inner surface of the retaining means at the region of maximum thickness and surface eccentricity of the retaining means; the lateral extent of the recess means being generally equal to a side of the polygonal shape.
The retaining means can be rotated relative to the shank, such that the re~ion o~ maximum thickness and surface eccentricity of the retaining means can be changed to compensate for wear and dimensional variations between the shank and walls of the recess.
Rotation of the resilient retainer collar and thus a change in the angular position of the wall surface eccentricity effects adjustment of the retaining force allowing in-field compensation for stretch, wear, and dimen-sional variants between the shank and the recess. This adjustment allows a preloading of a digger tooth so ~hat there is a gradual increase in load as opposed to the shock load that is encountered using conventional retainers.
Digger teeth using a resilient retainer according to the invention are economical to produce since large manufacturing tolerances can be compen-sated for by the retainer. The holders are economical to produce and use in that no holes are required to accommodate the retainers and large manufactur-ing tolerances can be compensated for. Economical field operations are pos-sible in that, with each new tooth, a new retainer is supplied and wear variations between holders can be compensated for readily.
The relieving of the inner surface of the retainer allows for the displacement of the resilient material during insertion of the shank into the recess. It is preferred that the width of the relief notch equals the length of one side of the polygonal portion of the shank and that it be located at the point of maximum eccentricity and wall thickness of the -;, . ~ , , , " , , ,, ; ,:
~ 6~g~ ~
retainer. This is so that, under compression of the retainer, a vertical as well as a horizontal holding force is generated.
When the resilient retainer is employed on a digger tooth of the type described, compensation for stretch in the digger tooth holder is made - 2a -iA
" , ; ., , . , , " :,- ................... . .
' ' : . '.'' . , .: . , '' ,,;: '"' . ,' ' :' :~':,:'". ' ,., ' ' '' ': ', '. ' ': , , ,: ;:.. , -., ''': ,-, ~0~9~62 by rotating the retainer relative to the digger tooth so that the maximum eccentricity of the retainer is in alignment with the maximum stretch on the holder. The retaining force generated has a component directed toward the center of the tooth as well as a component in the direction of the maximum stre~ch. The force component in the direction of stretch preloads the tooth so that5 when excavating force reversal occurs, there is a gradual build up on the tooth and retainer.
In drawings which illustrate embodiments of the invention which should not be taken as limiting the scope of the invention, Figure 1 shows an exploded assembly of a digger tooth and holder, Figure 2 shows a tooth in plan view, Figure 3 shows section 9-9 of the tooth of Figure 2, Figure 4 shows an enlarged end viel~ of a retainer, Figure 4a shows another retainer installed on a tooth, Figure 5 shows a retainer as instaLled in a holder that is neither worn nor stretched and as viewed through a section equivalent to section 9-9 of Figure 2, J Figure 6 shows a retainer as installed in a worn recess~Referring to Figure 1, a digger tooth 4 comprises a tip portion 24, adapted for excavating and a shank portion comprising two shanks 3, separated by a rectangular slot 25, and adapted for insertion into a holder 1. The holder 1 comprises a central portion 23 incorporating two recesses 2, one of which is shown. Each shank 3 is receivable in one of the recesses 2. Collar-shaped retainers 5 are adapted to fit an octagonal portion 6 on the shanks 3. The portions 7 on the shanks 3 have substantially circular cross-sections and serve to prevent axial displacement of the retainers 5 from the shanks 3 during removal of the tooth from the holder. Complemen-tary octagonal holes 8 are provided in the retainers 5 so that each retainer
- 3 ~
6~2 may be rotated to eight angular positions relative to a tooth. The re-tainers can be rotated to new angular positions relative to the tooth with no special tools, but the holding force generated by the co-acting octagonal flats prevents rotation of the retainer during insertion of the tooth into , the holder.
The plan view of the tooth shown in Figure 2 shows shanks 3 of a substantially rectangular shape. A cutting portion 10 of the tooth is basically wedge-shaped with relieved areas 11 providing improved excavation efficiency.
Referring to Figure 3, octagonal portion 6 of the shank is adapted to co-act with the internal octagonal surface 8 of the retainer 5.
Referring to Figure 4, octagonal surface 8 has relief provided a~
12 for material displacement during tooth insertion. The relief comprises a recess in the inner surface of the retainer 5 at its point of maximum thick- `
ness and surface eccentricity. The lateral extent of the recess is generally equal to a side of the octagonal shape. The eccentricity of the octagonal surface 8, relative to the circular periphery, is indicated at 13. The eccentricity 13 is determined as a function of the manufacturing tolerance between the shanks 3 of the tooth and the central portion of the holder 1.
The holder-shank combination illustrated in Figure 5 shows the holder 1 in section ~ith a retainer 5 on an octagonal portion 6 of a shank 3. The clearance space 17 surrounding the shank portion 6 is the normal manufacturing tolerance. The retainer 5 has relief 12 reduced from the size shown in Figure 4 due to the compressive force on the retainer 5 from the installation of the shank 3 into the holder 1. The retainer 5 is of a size that, under compressive force due to installation, the substantially cir-~ cular circumference is forced to conform to the shape of the shank recess 2.
; The holder 18 in Figure 6 is worn so that the clearance space 19 .;. . , . ,: :: : .. , ,;.. , . ~ : ~
2 ~
is larger than when the tooth and holder are new. The retainer 5, shown in Figure 6, has been rotated relative to the shank 6 so that relief 12 is located where shown. This is not the position for maximum wear compensation.
The point of maximum wear compensation occurs when the relief 12 is rotated from the position indicated in Figure 50 In the position shown in Fig-ure 6, there is a force component on the tooth shank 6 in the directions 20 and 21. The force component in direction 20 is particularly important in preventing tooth breakage due to cutting force reversal. The force com-ponent 20 holds one shank surface against the holder 18 so that dynamic shock loading of the shank is prevented. Under force reversal, the retainer must be compressed before the shank contacts the opposite side of the holder recess; this inhibits dynamic shock loading of the shank in the opposite direction.
Another embodiment of the retainer i5 shown installed on a tooth shank in Figure 4a. A longitudinal split 22 is provided in the retainer to ~acilitate installation of the retainer over the octagonal portion of the ~;
shank. This feature allows a comparatively rigid elastomer to be used for the retainer so that a force applied at 14 will cause a displacement at relie* 12 while the retainer material is being displaced along octagonal faces 15 and 16. The material displacement along faces 15 and 16 generates a biaxial force on the tooth shank and holder as with the embodiment of Figure 6.
- ;, : . .: ,~ . . '' .. . . :,
6~2 may be rotated to eight angular positions relative to a tooth. The re-tainers can be rotated to new angular positions relative to the tooth with no special tools, but the holding force generated by the co-acting octagonal flats prevents rotation of the retainer during insertion of the tooth into , the holder.
The plan view of the tooth shown in Figure 2 shows shanks 3 of a substantially rectangular shape. A cutting portion 10 of the tooth is basically wedge-shaped with relieved areas 11 providing improved excavation efficiency.
Referring to Figure 3, octagonal portion 6 of the shank is adapted to co-act with the internal octagonal surface 8 of the retainer 5.
Referring to Figure 4, octagonal surface 8 has relief provided a~
12 for material displacement during tooth insertion. The relief comprises a recess in the inner surface of the retainer 5 at its point of maximum thick- `
ness and surface eccentricity. The lateral extent of the recess is generally equal to a side of the octagonal shape. The eccentricity of the octagonal surface 8, relative to the circular periphery, is indicated at 13. The eccentricity 13 is determined as a function of the manufacturing tolerance between the shanks 3 of the tooth and the central portion of the holder 1.
The holder-shank combination illustrated in Figure 5 shows the holder 1 in section ~ith a retainer 5 on an octagonal portion 6 of a shank 3. The clearance space 17 surrounding the shank portion 6 is the normal manufacturing tolerance. The retainer 5 has relief 12 reduced from the size shown in Figure 4 due to the compressive force on the retainer 5 from the installation of the shank 3 into the holder 1. The retainer 5 is of a size that, under compressive force due to installation, the substantially cir-~ cular circumference is forced to conform to the shape of the shank recess 2.
; The holder 18 in Figure 6 is worn so that the clearance space 19 .;. . , . ,: :: : .. , ,;.. , . ~ : ~
2 ~
is larger than when the tooth and holder are new. The retainer 5, shown in Figure 6, has been rotated relative to the shank 6 so that relief 12 is located where shown. This is not the position for maximum wear compensation.
The point of maximum wear compensation occurs when the relief 12 is rotated from the position indicated in Figure 50 In the position shown in Fig-ure 6, there is a force component on the tooth shank 6 in the directions 20 and 21. The force component in direction 20 is particularly important in preventing tooth breakage due to cutting force reversal. The force com-ponent 20 holds one shank surface against the holder 18 so that dynamic shock loading of the shank is prevented. Under force reversal, the retainer must be compressed before the shank contacts the opposite side of the holder recess; this inhibits dynamic shock loading of the shank in the opposite direction.
Another embodiment of the retainer i5 shown installed on a tooth shank in Figure 4a. A longitudinal split 22 is provided in the retainer to ~acilitate installation of the retainer over the octagonal portion of the ~;
shank. This feature allows a comparatively rigid elastomer to be used for the retainer so that a force applied at 14 will cause a displacement at relie* 12 while the retainer material is being displaced along octagonal faces 15 and 16. The material displacement along faces 15 and 16 generates a biaxial force on the tooth shank and holder as with the embodiment of Figure 6.
- ;, : . .: ,~ . . '' .. . . :,
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A digger tooth retaining means for retaining a shank of a digger tooth in a recess of a holder; said retaining means comprising a resilient collar having an inner surface of a shape complementary to an exterior surface of said shank and a peripheral surface engageable with the walls of said recess;
said peripheral surface being eccentrically displaced with respect to said inner surface; the inner surface of the retaining means, and a co-acting sur-face of the shank, having complementary regular polygonal shapes, whereby the retaining means can be rotated relative to the shank, such that the region of maximum thickness and surface eccentricity of the retaining means can be changed to compensate for wear and dimensional variations between the shank and the wall of recess.
said peripheral surface being eccentrically displaced with respect to said inner surface; the inner surface of the retaining means, and a co-acting sur-face of the shank, having complementary regular polygonal shapes, whereby the retaining means can be rotated relative to the shank, such that the region of maximum thickness and surface eccentricity of the retaining means can be changed to compensate for wear and dimensional variations between the shank and the wall of recess.
2. The means of claim 1, wherein the polygonal shapes are octagonal shapes.
3. The means of claim 1, wherein the inner surface of the retaining means is relieved by a radially extending groove to allow for material dis-placement in the retaining means during insertion of the shank into the recess.
4. The means of claim 3, wherein the relief means comprises a recess in the inner surface of the retaining means at the region of maximum thickness and surface eccentricity of the retaining means; the lateral extent of the recess being generally equal to a side of the polygonal shape.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA322,641A CA1069962A (en) | 1976-05-27 | 1979-03-02 | Digger tooth retainer |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA253,465A CA1059183A (en) | 1976-05-27 | 1976-05-27 | Digger tooth retainer |
| CA322,641A CA1069962A (en) | 1976-05-27 | 1979-03-02 | Digger tooth retainer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1069962A true CA1069962A (en) | 1980-01-15 |
Family
ID=25668296
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA322,641A Expired CA1069962A (en) | 1976-05-27 | 1979-03-02 | Digger tooth retainer |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1069962A (en) |
-
1979
- 1979-03-02 CA CA322,641A patent/CA1069962A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |