CA1119791A - Segment-shaped blade - Google Patents
Segment-shaped bladeInfo
- Publication number
- CA1119791A CA1119791A CA000335153A CA335153A CA1119791A CA 1119791 A CA1119791 A CA 1119791A CA 000335153 A CA000335153 A CA 000335153A CA 335153 A CA335153 A CA 335153A CA 1119791 A CA1119791 A CA 1119791A
- Authority
- CA
- Canada
- Prior art keywords
- tooth
- blade
- plane
- triangular
- pointed
- 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
- Tyre Moulding (AREA)
Abstract
Abstract of the Disclosure A segment-shaped blade is provided for use in a rotatable cylindrical tool for machining elastic material, particularly pneumatic rubber tyres for vehicles. The blade comprises pointed triangular teeth, which are provided on a convex outer edge and are staggered and divided by radial cuts. Each radial cut extends only as far as to the root of the tooth concerned and each triangular tooth is divided by one or more radial cuts into at least two triangular tooth portions which have pointed tips that are much more slender than the pointed tip of the original tooth.
Description
~ his invention relates to a segment-shaped blade for use in a rotatable cyli~drical tool ~or machlning elastic material, particularly pneumatic rubber tyres for vehicles, comprising pointed triangular teeth, which are provided on a convex outer edge and are staggered and divided by radial cuts.
German Patent Specification 1,1659843 discloses such a blade? in which said radial cuts extend below the roots o~ the teeth so that the latter are M-shaped and ha~e double prongs an~ a strong root~ ~his is intended to ensure that a breaking out of individual teeth is prevented with high safety. Another blade known from that patent speci~ication has triangular teethg which are not slit but are laterally bent to di~ferent sides o~ the blade in alternation.
~ yre rasps provided with the known blades having M-shaped or triangular teeth are thus available ~`or roughe~ing the rubber covering of worn vehicle t~res ~o be retreaded. ~hereas the set teeth can engage the tyre in a ver~ large width so that the surface o~ the tyre can be e~fecti~ely roughened~ these teeth can ~e u~ed to provide only a very coarse roughened pattern.
It is known to use also roughening members set with needles to roughen the side walls o~ a pneumatic tyre which is to be retreaded~ To ensure that the cords lying on the side walls o~ the tyre only under a thin rubber layer will not be damaged~ it is known to use tools provided with wire brushes. Whereas such tools ensure a fine roughening o~ -the rubber layer9 they cannot always be used to full ad~antage because the bristles are . . ,.~ ; ~..
;
bent down after a relatively short time. An unusually strong development of heat has even resulted ln a burning of the tyre.
~ inally~ steel discs provided with tungsten carbide splinters anchored at the periphery of the disc have also been used to roughen the side walls of tyres~
In that case, a high contact pressure is required and gives rise to an undesirably high operating temperature.
It is an object of the invention so to design - 10 the blade which has been described first hereinbefore that its teeth can be used like the k~own wire brushes for a fine roughening of the rubber layer on the side walls of a pneumatic tyre whereas a high operating tem-perature can be avoided. In -the blade described, that 'f object is accomplished according to the inven1tion primarily in that each radial cut extends only as far as to the root of the tooth con ~rned and that each triangular tooth is divided b~ one or more radial cuts into at least two triangular tooth portions which have pointed tips that are much more slender than the pointed tip o~ the original tooth.
Because the radial cuts in the trian~ular teeth of such blade extend o~ly as far as to the roots of the teeth, each tooth has at least two tooth portions7 the pointed -tips of which when used to roughen the surface of the rubber tyre act like the above-mentioned needles and brushes ~o that the resulting roughened pa-ttern is fine and particularly favourable for the vulcanization of the raw tread to be appliedl Nevertheless, the opera-ting temperature remains so low that the previously feared
German Patent Specification 1,1659843 discloses such a blade? in which said radial cuts extend below the roots o~ the teeth so that the latter are M-shaped and ha~e double prongs an~ a strong root~ ~his is intended to ensure that a breaking out of individual teeth is prevented with high safety. Another blade known from that patent speci~ication has triangular teethg which are not slit but are laterally bent to di~ferent sides o~ the blade in alternation.
~ yre rasps provided with the known blades having M-shaped or triangular teeth are thus available ~`or roughe~ing the rubber covering of worn vehicle t~res ~o be retreaded. ~hereas the set teeth can engage the tyre in a ver~ large width so that the surface o~ the tyre can be e~fecti~ely roughened~ these teeth can ~e u~ed to provide only a very coarse roughened pattern.
It is known to use also roughening members set with needles to roughen the side walls o~ a pneumatic tyre which is to be retreaded~ To ensure that the cords lying on the side walls o~ the tyre only under a thin rubber layer will not be damaged~ it is known to use tools provided with wire brushes. Whereas such tools ensure a fine roughening o~ -the rubber layer9 they cannot always be used to full ad~antage because the bristles are . . ,.~ ; ~..
;
bent down after a relatively short time. An unusually strong development of heat has even resulted ln a burning of the tyre.
~ inally~ steel discs provided with tungsten carbide splinters anchored at the periphery of the disc have also been used to roughen the side walls of tyres~
In that case, a high contact pressure is required and gives rise to an undesirably high operating temperature.
It is an object of the invention so to design - 10 the blade which has been described first hereinbefore that its teeth can be used like the k~own wire brushes for a fine roughening of the rubber layer on the side walls of a pneumatic tyre whereas a high operating tem-perature can be avoided. In -the blade described, that 'f object is accomplished according to the inven1tion primarily in that each radial cut extends only as far as to the root of the tooth con ~rned and that each triangular tooth is divided b~ one or more radial cuts into at least two triangular tooth portions which have pointed tips that are much more slender than the pointed tip o~ the original tooth.
Because the radial cuts in the trian~ular teeth of such blade extend o~ly as far as to the roots of the teeth, each tooth has at least two tooth portions7 the pointed -tips of which when used to roughen the surface of the rubber tyre act like the above-mentioned needles and brushes ~o that the resulting roughened pa-ttern is fine and particularly favourable for the vulcanization of the raw tread to be appliedl Nevertheless, the opera-ting temperature remains so low that the previously feared
- 2 -; burning is entirely avoidedO
Another advantage of the blade according to the invention resides in its relatively lo~g edge li~e. ~hi~
is due to the fact that the tooth portions resulting ~rom the radial cuts are much more pointed than the known triangular teath so that the~ can be worn to much larger depth because they are smaller in cross-section. ~inally, the blade according to the invention has virtually a double working capacity because it has at least twice the number o~
pointed tooth tips o~ the conventional blade.
In a preferred embodiment of the invention, the tooth portions of a tooth are equal in size and are bent out of the plane of the blade to different sides, in known manner, or one tooth portion lies in the pl~ne o~ the blade and the other tooth portion is ~ent out of the plane of -the blade. Qbviously, the manufacture of such blades is not more complicated than the manufa¢ture of blades having wide ; triangular teeth because the incLividual teeth can be divided by an ordina~y cutting tool and it is not necessary to bend all tooth portions out of the plane of the blade.
~` ~lso in a preferred embodiment o~ ths invention, a wide-root triangular tooth is provided with one or two radial cu~s before and behind its pointed tip~ the long middle tooth portion is offset to one side o~ the plane o~ the blade, the short other tooth portions are bent to the other side of the plane of the blade or lie in the plane o~ the blade, and all tooth points terminate pre- -~erably in an imaginary arcuate plane. In a wide-root triangular tooth divided into three tooth portions, the stronger middle tooth pcrtion has the strongest action to remove material and the two o-ther tooth portions9 which are weaker, ensure a particularly ~ine roughening of the rubber material to be machined. If a tooth is divided into more parts, i.eO; into four or five tooth portions, the blade will act like a wire brush in tha-t the rubber layer or the tyre will be finely roughened whereas large rubber particles will not be removed and high operating temperatures will not arise~
Some illustrative embodiments of the invention ~ 10 are diagrammaticallg shown on the accompanying drawing, -~ in which ~ig. 1 is a side elevation showing a co~venticnal blade~
~ig. 2 is a sectional view taken on line II-II in Fig. 1, ~ig. 3 a side elevation showing an embodiment o~
the blade according to the invention, ~ig. 4 a sectional view tak~n on line IV~IV in Fig. 3, ~`ig. 5 a ~ide elevation showing another embodiment of a blade aceording to the invention, ~ig. 6 a sectional view taken on line VI-VI in ~ig 5 and ~ig . 7 a perspective view, partly broken away7 showing the blade according to the invention as illustrated in Fig 5.
It is apparent from ~ig. 1 -that the conventional :.
blade~ 2 are segment-shaped and on their conve~ outer edge are provided with triangular teeth 1, which are separated by spaces 3 50 that the spacing 4 o~ the teeth 1 is approximately as large as the height 5 of the teeth.
~s is shown in ~ig, 29 the teeth 1 of blade 2 are bent out of the plane of the blade in alternation~
~he invention ls ba~ed on the tooth shape shown in Figs. 1 a~d 2 and in accordance with Fig. 3 teaches to divide such tooth 6 by an appro~imately radial cut 7 into two portions 8 and 9. In acoordanoe with Fig. 4 portion 8 i8 bent to the left and portion 9 i~ bent to the right out of the plane 10 o~ the blade~
Depending ~n the direction 13 or 14 in which the blade is moved, the edges 11 and 12 defining the radial : out 7 have a particularly strong action to remove material.
~hat action will be stronger in a~ case than the action o~
: the edges 15 and 16, which include an angle 18 with the radial plane 17.
It is readily apparent ~rom Fig. 3 that owing .~ to the division of the teeth the number of the pointed tips o~ the teeth 6 of blade 10 is ~wice the number of the pointed tips of the teeth 1 of blade 2 so that the 2 0 blade 10 can give twice the output in practice~
: Owing to the above-mentioned strong action of the tooth portions 89 9 o~ the several teeth 6~ -the pressure applied by a cylindrical to~l carrying such blades 10 to the material being machined can be greatly reduced so that a very ~ine roughened surface pattern will be ob~ained on rubber material which has been machined and the operating temperature remains so low that a burning of the rubber ma-terial being machined will be reliably avoided.
Besides, the comparable tooth cross-sections .
- . , ~ . ..
.
~ of the teeth 6 and 1 differ in a given haight so -that the .
~ teeth 5 of blade 10 shown in ~ig. 3 can be worn to a much ; larger depth, i.e ~ ~or a longer time, before they are blunt and can no longer be used. As a result 9 the blade 10 has a ~- much longer life than the conventional blade 2 in Fig~ 1.
It is apparent from ~igs. 5 to 7 that each tooth 19 of blade 20 is di~ided into three tooth portions 24, 25 7 26 by two radial cuts 22~ 23 disposed beEore and behind the pointed tip 21 of the tooth. As is shown in ~ig. 6, the relatively thick middle tooth portion 25 is o~set to one side of the plane 20 of the blade and the two other tooth portion~ 24, 26, which are ~horter, are merely bent to the other side oE the plane 20 of the blade.
Fig. 6 shows the offset middle tooth portion 25 oE the too-th 28 as well as the middle tooth portion 33 of the following tooth 29, which tooth portion is o~fset to the opposite side. ~he position o~ the teeth is particularly clearly apparent ~rom ~ig. 7, in which ~he bla~e 20 is shown in perspecti~e. The middle tooth portion 34 of the tooth 35 is offset to the right side of the plane 20 o* the blade and ~he two tooth portions 36, 37 o~ the tooth are bent -to the le~t side-o~ the plane 20 of the blade. ~his relationship is inverted in the next following tooth 38, in which the middle tooth portion 39 is offset to the left of the pla~e 20 o~ the blade i.e~ on the side opposite to the of~set tooth portion 34 o~ the preceding tooth 35, and the two shorter tooth portions 40, 4~ are bent to the right side of the p~Lane ~0 of the blade, iOe~ to the side which is opposite to the tooth portions 36, 37 o~
tooth 35 which are bent to the left.
The invention is not restricted to the embodiments shown by way of example. ~he tooth portions 36~ 37 and 40 41 may lie in the plane 20 of the blade or one o~ the shorter tooth portions of each tooth may ~emain in the plane of the blade whereas the other shorter tooth portions ~ are bent. ~'he points of all these tooth portions 34 to 41 : lie preferably in an imaginary common plane9 which is curved ; in accordance with the segment-shaped blade, so that the :- tooth portions act at the same time. ~he middle tooth portion of each tooth 35, 38 of the blade 20 is stronger in most cases and removes the largest amount of material.
The two other tooth portions 36, 37, 40, 41, which are weaker, ensure that the rubber material to be machined will be finely roughened.
I~ the blade embodying the invention is provlded with a triangular tooth which has a particularly wide root, such tooth may be divided into four or five parts~ In that case the several tooth portions are ~o o~fset or bent relative to each other that their pointed tips lie in a single curved plane and a single blade according to the lnvention has pointed tooth tips e~ual in ~umber to the bristles of the steel brushes previously empl~yed~
. As has been mentioned, a triangular tooth can be ; divided by radial cuts~ If one radial cut extends through the point of the triangular tooth, the cuts on the left and right of the radial eut may either be parallel thereto or may also extend in a radial direGtion.
~ 7 ~
,` .
,,
Another advantage of the blade according to the invention resides in its relatively lo~g edge li~e. ~hi~
is due to the fact that the tooth portions resulting ~rom the radial cuts are much more pointed than the known triangular teath so that the~ can be worn to much larger depth because they are smaller in cross-section. ~inally, the blade according to the invention has virtually a double working capacity because it has at least twice the number o~
pointed tooth tips o~ the conventional blade.
In a preferred embodiment of the invention, the tooth portions of a tooth are equal in size and are bent out of the plane of the blade to different sides, in known manner, or one tooth portion lies in the pl~ne o~ the blade and the other tooth portion is ~ent out of the plane of -the blade. Qbviously, the manufacture of such blades is not more complicated than the manufa¢ture of blades having wide ; triangular teeth because the incLividual teeth can be divided by an ordina~y cutting tool and it is not necessary to bend all tooth portions out of the plane of the blade.
~` ~lso in a preferred embodiment o~ ths invention, a wide-root triangular tooth is provided with one or two radial cu~s before and behind its pointed tip~ the long middle tooth portion is offset to one side o~ the plane o~ the blade, the short other tooth portions are bent to the other side of the plane of the blade or lie in the plane o~ the blade, and all tooth points terminate pre- -~erably in an imaginary arcuate plane. In a wide-root triangular tooth divided into three tooth portions, the stronger middle tooth pcrtion has the strongest action to remove material and the two o-ther tooth portions9 which are weaker, ensure a particularly ~ine roughening of the rubber material to be machined. If a tooth is divided into more parts, i.eO; into four or five tooth portions, the blade will act like a wire brush in tha-t the rubber layer or the tyre will be finely roughened whereas large rubber particles will not be removed and high operating temperatures will not arise~
Some illustrative embodiments of the invention ~ 10 are diagrammaticallg shown on the accompanying drawing, -~ in which ~ig. 1 is a side elevation showing a co~venticnal blade~
~ig. 2 is a sectional view taken on line II-II in Fig. 1, ~ig. 3 a side elevation showing an embodiment o~
the blade according to the invention, ~ig. 4 a sectional view tak~n on line IV~IV in Fig. 3, ~`ig. 5 a ~ide elevation showing another embodiment of a blade aceording to the invention, ~ig. 6 a sectional view taken on line VI-VI in ~ig 5 and ~ig . 7 a perspective view, partly broken away7 showing the blade according to the invention as illustrated in Fig 5.
It is apparent from ~ig. 1 -that the conventional :.
blade~ 2 are segment-shaped and on their conve~ outer edge are provided with triangular teeth 1, which are separated by spaces 3 50 that the spacing 4 o~ the teeth 1 is approximately as large as the height 5 of the teeth.
~s is shown in ~ig, 29 the teeth 1 of blade 2 are bent out of the plane of the blade in alternation~
~he invention ls ba~ed on the tooth shape shown in Figs. 1 a~d 2 and in accordance with Fig. 3 teaches to divide such tooth 6 by an appro~imately radial cut 7 into two portions 8 and 9. In acoordanoe with Fig. 4 portion 8 i8 bent to the left and portion 9 i~ bent to the right out of the plane 10 o~ the blade~
Depending ~n the direction 13 or 14 in which the blade is moved, the edges 11 and 12 defining the radial : out 7 have a particularly strong action to remove material.
~hat action will be stronger in a~ case than the action o~
: the edges 15 and 16, which include an angle 18 with the radial plane 17.
It is readily apparent ~rom Fig. 3 that owing .~ to the division of the teeth the number of the pointed tips o~ the teeth 6 of blade 10 is ~wice the number of the pointed tips of the teeth 1 of blade 2 so that the 2 0 blade 10 can give twice the output in practice~
: Owing to the above-mentioned strong action of the tooth portions 89 9 o~ the several teeth 6~ -the pressure applied by a cylindrical to~l carrying such blades 10 to the material being machined can be greatly reduced so that a very ~ine roughened surface pattern will be ob~ained on rubber material which has been machined and the operating temperature remains so low that a burning of the rubber ma-terial being machined will be reliably avoided.
Besides, the comparable tooth cross-sections .
- . , ~ . ..
.
~ of the teeth 6 and 1 differ in a given haight so -that the .
~ teeth 5 of blade 10 shown in ~ig. 3 can be worn to a much ; larger depth, i.e ~ ~or a longer time, before they are blunt and can no longer be used. As a result 9 the blade 10 has a ~- much longer life than the conventional blade 2 in Fig~ 1.
It is apparent from ~igs. 5 to 7 that each tooth 19 of blade 20 is di~ided into three tooth portions 24, 25 7 26 by two radial cuts 22~ 23 disposed beEore and behind the pointed tip 21 of the tooth. As is shown in ~ig. 6, the relatively thick middle tooth portion 25 is o~set to one side of the plane 20 of the blade and the two other tooth portion~ 24, 26, which are ~horter, are merely bent to the other side oE the plane 20 of the blade.
Fig. 6 shows the offset middle tooth portion 25 oE the too-th 28 as well as the middle tooth portion 33 of the following tooth 29, which tooth portion is o~fset to the opposite side. ~he position o~ the teeth is particularly clearly apparent ~rom ~ig. 7, in which ~he bla~e 20 is shown in perspecti~e. The middle tooth portion 34 of the tooth 35 is offset to the right side of the plane 20 o* the blade and ~he two tooth portions 36, 37 o~ the tooth are bent -to the le~t side-o~ the plane 20 of the blade. ~his relationship is inverted in the next following tooth 38, in which the middle tooth portion 39 is offset to the left of the pla~e 20 o~ the blade i.e~ on the side opposite to the of~set tooth portion 34 o~ the preceding tooth 35, and the two shorter tooth portions 40, 4~ are bent to the right side of the p~Lane ~0 of the blade, iOe~ to the side which is opposite to the tooth portions 36, 37 o~
tooth 35 which are bent to the left.
The invention is not restricted to the embodiments shown by way of example. ~he tooth portions 36~ 37 and 40 41 may lie in the plane 20 of the blade or one o~ the shorter tooth portions of each tooth may ~emain in the plane of the blade whereas the other shorter tooth portions ~ are bent. ~'he points of all these tooth portions 34 to 41 : lie preferably in an imaginary common plane9 which is curved ; in accordance with the segment-shaped blade, so that the :- tooth portions act at the same time. ~he middle tooth portion of each tooth 35, 38 of the blade 20 is stronger in most cases and removes the largest amount of material.
The two other tooth portions 36, 37, 40, 41, which are weaker, ensure that the rubber material to be machined will be finely roughened.
I~ the blade embodying the invention is provlded with a triangular tooth which has a particularly wide root, such tooth may be divided into four or five parts~ In that case the several tooth portions are ~o o~fset or bent relative to each other that their pointed tips lie in a single curved plane and a single blade according to the lnvention has pointed tooth tips e~ual in ~umber to the bristles of the steel brushes previously empl~yed~
. As has been mentioned, a triangular tooth can be ; divided by radial cuts~ If one radial cut extends through the point of the triangular tooth, the cuts on the left and right of the radial eut may either be parallel thereto or may also extend in a radial direGtion.
~ 7 ~
,` .
,,
Claims (3)
1. A segment-shaped blade for use in a rotatable cylindrical tool for machining elastic material, particular ly pneumatic rubber tyres for vehicles, comprising pointed triangular teeth, which are provided on a convex outer edge and are staggered and divided by radial cuts, characterized in that each radial cut extends only as far as to the root of the tooth concerned and that each triangular tooth is divided by one or more radial cuts into at least two triangular tooth portions which have pointed tips that are much more slender than the pointed tip of the original tooth.
2. A blade as defined in claim 1, characterized in that the tooth portions of a tooth are equal in size and are bent out of the plane of the blade to different sides, in known manner, or one tooth portion lies in the plane of the blade and the other tooth portion is bent out of the plane of the blade.
3. A blade as defined in claim 1, characterized in that a wide-root triangular tooth is provided with one or two radial cuts before and behind its pointed tip, the long middle tooth portion is offset to one side of the plane of the blade, the short other tooth portions are bent to the other side of the plane of the blade or lie in the plane of the blade, and all tooth points terminate preferably in an imaginary arcuate plane.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000335153A CA1119791A (en) | 1979-09-06 | 1979-09-06 | Segment-shaped blade |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000335153A CA1119791A (en) | 1979-09-06 | 1979-09-06 | Segment-shaped blade |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1119791A true CA1119791A (en) | 1982-03-16 |
Family
ID=4115097
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000335153A Expired CA1119791A (en) | 1979-09-06 | 1979-09-06 | Segment-shaped blade |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1119791A (en) |
-
1979
- 1979-09-06 CA CA000335153A patent/CA1119791A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |