A Tire Rasp Blade Ein Reifenraspelblatt Une Lame De Râpe À Pneumatique

Europäisches Patentamt

(19) European Patent Ofﬁce Ofﬁce européen des brevets (11) EP 0 640 423 B1

(12) EUROPEAN PATENT SPECIFICATION

(45) Date of publication and mention (51) Int. Cl.7: B23D 71/02 of the grant of the patent: 05.01.2000 Bulletin 2000/01

(21) Application number: 94650020.4

(22) Date of ﬁling: 31.08.1994

(54) A tire rasp blade Ein Reifenraspelblatt Une lame de râpe à pneumatique

(84) Designated Contracting States: (72) Inventor: Jensen, Wayne AT BE CH DE DK ES FR GB GR IT LI LU NL SE Olympia Fields, Illinois 60461 (US)

(30) Priority: 31.08.1993 US 114773 (74) Representative: Casey, Lindsay Joseph et al (43) Date of publication of application: F. R. Kelly & Co. 01.03.1995 Bulletin 1995/09 27 Clyde Road Ballsbridge (73) Proprietor: Dublin 4 (IE) B & J MANUFACTURING COMPANY Glenwood Illinois 60425 (US) (56) References cited: US-A- 3 879 825 US-A- 5 033 175

Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 0 640 423 B1 Printed by Xerox (UK) Business Services 2.16.7/3.6 12EP 0 640 423 B1

Description [0007] The present invention provides a bent tire rasp blade for use in a tire buffing machine. The bent blade [0001] The present invention relates to a tire rasp has a nonplanar elongated body having two planar por- blade for use in tire buffing machines. Relevant prior art tions or "flats." The blade also includes an outer working is disclosed in U.S. Patent Nos. 5,033,175, 4,019,234 5edge having a plurality of teeth which extend in a direc- and 2,703,446. tion generally parallel to the direction of hub rotation. [0002] Tire buffing machines are well known in the tire The outer working edge is comprised of two curved sur- retreading industry. Conventionally, a tire buffing faces, each curve defining a portion of an ellipse. The machine includes both a structure for mounting a used two curved elliptical surfaces of the outer working edge tire and a rasp hub which removes the worn tread from 10 intersect at a mid-portion of the blade where the two the used tire prior to the retreading process. The used planar end portions of the blade body are joined. tire is rotated while it is held against the rapidly rotating [0008] The use of an elliptically-shaped outer working rasp hub whose outside perimeter is provided with a edge compensates for the inclined positioning of the multitude of tire rasp blades. When so engaged against blades on the hub. As a result, the "effective geometry" the used tire, the blades cut or shear small segments of 15 of the working edges of the inclined blades as they rubber from the worn tread surface area of the tire. In rotate on the hub is circular. this way, the tire is "buffed" to remove the unwanted [0009] In the context of the present invention, the used tread and to achieve an evenly textured surface terms "nonplanar," "bent," and "V-shaped" are all suitable for retreading. intended to describe the geometry of rasp blades once [0003] Tire rasp blades, together with intervening 20 they have been assembled within the hub assembly, spacers, are assembled on the periphery of the rasp and then viewed radially toward the hub's axis of rota- hub between the hub front and back plates. U.S. Patent tion from a point outside the circumference of the hub. Nos. 2,703,446 and 4,019,234 disclose such conven- Thus, a "nonplanar" blade body is one whose length, tional prior art rasp hub assemblies wherein the back from end to end, does not lie in a single plane. plate of the hub has axially directed support pins on 25 [0010] "Symmetrical" as to describe blades is defined which are mounted the rasp blades and spacers. The herein to mean a type of blade in which a repetitive pat- front plate is then assembled onto the support pins tern is utilized, such that one half of the blade is a mirror against the assembled blades and spacers and locked image of the other. However, while the preferred into place. embodiment of the present invention includes the use of [0004] Use of bent blades with flat spacers is 30 symmetrical blades, the present invention also contem- described in U.S. Patent No. 5,033,175 which discloses plates that the blades may be nonplanar and asymmet- a tire rasp blade having the features of the preamble of rical, and these forms are contemplated by the present Claim 1. This arrangement creates a circumferentially invention as well. interlocked hub with less potential for mechanical failure [0011] Additionally, the bent blade is provided with at high rotational speeds. 35 teeth which are arranged generally parallel to the axis of [0005] It has been conventional practice to form the rotation of the hub, as shown in Figure 3. In a preferred outer-most portion or "working edge" of the tire rasp embodiment, the teeth are angularly offset from the flats blade as a segment of a circle. That is, the working edge by an angle of about 3° to 5°. In this embodiment, the is in the form of an arc defined by a common radius. leading edge of each tooth -- the edge pointing in the However, when such tire rasp blades are assembled 40 direction of hub rotation -- will be displaced to one side into a hub, they are inclined relative to the direction of of the blade body along one planar portion of the blade rotation of the hub. As a result, the actual geometry of and to the other side of the blade body along the other the working edge of each blade -- as it is rotated on the planar portion of the blade. hub -- is no longer circular relative to the surface of the [0012] It has also been determined that the present tire being buffed. In effect, as the buffing hub rotates, the 45 invention gives the operator better control and stability working edge of the inclined tire rasp blades cyclically during cutting while also imparting an enhanced buffing move toward and away from the surface of the tire. This, action to the tire. Two reasons arising from the novel in turn, causes inefficient operation and uneven buffing bent blade/tooth arrangement of the present invention of the tire. are believed responsible for the enhanced stability [0006] The present invention having the features of 50 which results. claim 1 is directed to a tire rasp blade having elements [0013] First, it is believed the symmetrical blade con- whose shape and configuration affords it certain advan- figuration of the present invention contributes to the tages over prior art rasp blade designs. Moreover, the overall stability of the hub assembly. A force is exerted tire rasp blade of the present invention enhances per- by the tire onto the first planar portion of the blade as it formance. This is achieved because the configuration of 55 buffs the tire. Then, as the second planar portion of the the blade body and working edge permits the teeth on blade sweeps across the tire, an equal and opposite the working edge to attack the tire tread with more uni- force is exerted by the tire on that portion. These alter- formity and precision. nating, equal and opposing forces are believed to serve

2 34EP 0 640 423 B1 as constant stabilizers for the hub assembly as the hub Because the blade 10 is bent along its longitudinal axis, rotates. when assembled into the tire buffing machine hub, each [0014] Second, the use of the elliptical curved working planar portion 14 and 16 will be disposed at an angle edge allows the working edge to present a uniform relative to the hub's direction of rotation (and to a plane cylindrical surface of teeth to the tire. Because the blade 5normally intersecting the hub's axis). In turn, this angu- is positioned at an angle to the hub's axis, the elliptical lar orientation will, in effect, "convert" the elliptical work- working surface is "converted" to a circular surface ing edge into a circular surface as presented to the tire when mounted on and rotating with the hub. In this man- being buffed. FIGURE 4 is intended to more graphically ner, the blade's teeth are applied more uniformly to the illustrate the elliptical geometry concept of the present tire in the buffing operation. 10 invention (the actual dimensions have been exagger- [0015] While the bent blades of the present invention ated for purposes of illustration). As shown, the typical can be fabricated from a pre-formed rigid material as is circular working edge (in phantom) with radius R has conventional in the art, such as carbon-steel, they can been modified to comprise two elliptical surfaces E1 and also be usefully fabricated from a conformable, ductile E2. material or from a conformable and resilient material. 15 [0019] Thus, the plurality of bent blades, all with dual [0016] A hybrid fabrication has been found suitable, as elliptical working edges, will establish a generally cylin- well. In this hybrid fabrication, a conformable ductile drical buffing surface which uniformly and evenly material is used to fabricate a planar blade. Then, the attacks the tire being buffed. teeth, as well as a portion of the blade body extending [0020] Those of skill in the art will understand that the approximately 1/8 inch 3.18 mm below the teeth, are 20 specific elliptical surface to be used will be dependent induction-hardened. The remaining blade body portion upon the size of the particular blade and its angle of dis- remains untreated, and the blade is then bent into placement. As shown in FIGURE 5, the radius R is proper position. In this way, should the hardened blade determined for the blade depending upon the particular portion crack, the remaining blade portion will not crack, rasp hub size (conventional hubs are typically 9, 10.5 and the blade to remain intact. Alternatively, the ductile 25 26.67 cm or 11.5 29.21 cm inches in diameter). The portion of the blade, in its annealed state, could occupy Angle A is the angle of the inclination of the blade (or a middle portion of the blade. each planar portion) on the hub; that is, the angle [0017] An embodiment of the present invention will formed by the blade or planar portion on the hub and a now be described, by way of example, with reference to plane which is normal to the hub's axis of rotation. the accompanying drawings, in which:- 30 Given these data, the ellipse used to define the working edge of the blade may be made with a major axis 2X FIGURE 1 is a side elevational view of the bent tire and a minor axis 2R, whereX=R (Secant of A). rasp blade of the present invention, showing the [0021] In the particularly preferred configuration of the elliptical curved surfaces of the working edge; blade, shown in FIGURES 1 and 2, the angle each pla- FIGURE 2 is a plan view of the bent tire rasp blade 35 nar portion 14 and 16 makes with a plane normally of FIGURE 1; intersecting the cylindrical hub axis is approximately 4° FIGURE 3 is an enlarged plan view showing a por- for a 9-inch 22.86 cm diameter hub, and is approxi- tion of the bent rasp blade and the orientation of the mately 3° for a 11.5-inch 29.21 cm diameter hub. teeth relative to the blade body; [0022] It is also particularly advantageous in the prac- FIGURE 4 is a schematic illustration of the elliptical 40 tice of the present invention to position at least one set surfaces used in accordance with the present of mounting holes 28 at the mid-point of each planar invention relative to conventional circular surfaces; end portion, 14 and 16 respectively. Positioning the and mounting holes in this way allows the use of only a sin- FIGURE 5 is a diagram illustrating the determina- gle support pin (in the associated rasp blade hub) for tion of the elliptical surface for use in the present 45 each blade planar portion. Having the pin centered on invention. each planar portion will prevent displacement of the planar portion in the rotating hub, even in the rare event [0018] In accordance with the present invention, the that the blade breaks along vertex 18. Thus, a safer bent tire rasp blade, designated generally as 10, design is achieved. includes an elongated, generally arcuate, nonplanar 50 [0023] It will be appreciated by those skilled in the art body 12. The nonplanar or "bent" body has two planar that various modifications and changes can be made to end portions 14 and 16 which meet at a mid-portion of the illustrated embodiments without departing from the the body, thereby forming a vertex 18. Blade 10 also scope of the appended claims. includes a working edge 20 having a plurality of teeth 22, as is well known in the art. The configuration of the 55 Claims working edge 20 includes two curved surfaces 24 and 26 each of which defines a portion of an ellipse. The two 1. A tire rasp blade (10) for use in a tire buffing elliptical surfaces intersect at the midpoint of the blade. machine which includes a rotating hub, comprising:

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an elongated, generally arcuate and nonplanar 11. A tire rasp blade (11) as claimed in any of Claims 1- body (12) having two generally planar end por- 10, wherein said working edge (20) includes a plu- tions (14, 16) each having first and second rality of teeth (22) all disposed at a uniform angle opposing sides, said generally planar end por- relative to said blade body, said teeth (22) being in tions (14, 16) intersecting in a vertex (18) posi- 5substantially the same plane as the plane normal to tioned at a mid-portion of said body; and the axis of hub rotation; said teeth (22) each having a working edge (20) having two curved sur- a leading edge and a trailing edge; the leading faces (24, 26), edges of the teeth (22) of one planar end portion characterised in that being displaced to one side of said body and the each of said curved surfaces (24, 26) defines a 10 leading edges of the teeth (22) of the other planar portion of an ellipse having unequal major and end portion being displaced to the other side of said minor axes and provides an effectively circular body. working edge (20) when said blade (10) is mounted to and rotated on said hub. Patentansprüche 15 2. A tire rasp blade (10) as claimed in Claim 1, 1. Reifenraspelblatt (10) zur Verwendung in einer eine wherein the two curved elliptical surfaces of said rotierende Nabe aufweisenden Reifenaufrauhma- working edge (20) intersect at said midpoint. schine, das folgendes umfaßt: einen länglichen, allgemein bogenförmigen und nicht ebenen Körper 3. A tire rasp blade (10) as claimed in Claim 1 or Claim 20 (12) mit zwei allgemein ebenen Endteilen (14, 16), 2 wherein the angle each said planar end portion die jeweils eine erste und eine zweite einander (14, 16) makes with a plane normally intersecting gegenüberliegende Seite haben, wobei die the rotating hub is approximately either 3° or 4°. genannten allgemein ebenen Endteile (14, 16) sich in einem Scheitel (18) schneiden, der sich an einem 4. A tire rasp blade (10) as claimed in any of Claims 1- 25 mittleren Teil des genannten Körpers befindet; und 3, wherein said blade (10) is symmetrical about its eine Arbeitskante (20) mit zwei gekrümmten Ober- longitudinal midpoint. flächen (24, 26), dadurch gekennzeichnet, daß jede der genannten gekrümmten Oberflächen (24, 26) 5. A tire rasp blade (10) as claimed in any of Claims 1- einen Teil einer Ellipse mit ungleicher Haupt- und 4, wherein said working edge (20) includes a plural- 30 Nebenachse definiert und eine effektiv kreisförmige ity of teeth (22) all disposed at a uniform angle rela- Arbeitskante (20) bereitstellt, wenn das genannte tive to said blade body; said teeth (22) each having Blatt (10) an der genannten Nabe montiert ist und a leading edge and a trailing edge; said leading rotiert. edges of the teeth (22) of one planar end portion being displaced to said first side of said body and 35 2. Reifenraspelblatt (10) nach Anspruch 1, bei dem the leading edges of the teeth (22) of the other pla- sich die zwei gekrümmten elliptischen Oberflächen nar end portion being displaced to said second side der genannten Arbeitskante (20) an dem genann- of said body. ten Mittelpunkt schneiden.

6. A tire rasp blade (10) as claimed in any of Claims 1- 40 3. Reifenraspelblatt (10) nach Anspruch 1 oder 4, wherein said working edge includes a plurality of Anspruch 2, bei dem der Winkel, den jedes ebene teeth (22) separated by a plurality of arcuate cut- Endteil (14, 16) zu einer normalerweise die rotie- outs, the vertex of said nonplanar body being rende Nabe schneidenden Ebene hat, ungefähr located at a tooth. entweder 3° oder 4° beträgt. 45 7. A tire rasp blade (10) as claimed in any of Claims 1- 4. Reifenraspelblatt (10) nach einem der Ansprüche 1 6, wherein said body is generally rigid. - 3, bei dem das genannte Blatt (10) um seinen lon- gitudinalen Mittelpunkt symmetrisch ist. 8. A tire rasp blade (10) as claimed in any of Claims 1- 7, wherein said body is conformable and resilient. 50 5. Reifenraspelblatt (10) nach einem der Ansprüche 1 - 4, bei dem die genannte Arbeitskante (20) eine 9. A tire rasp blade (10) as claimed in any of Claims 1- Mehrzahl von Zähnen (22) aufweist, die alle in 8, wherein the working edge is induction-hardened. einem einheitlichen Winkel relativ zu dem genannten Blattkörper angeordnet sind; wobei die genann- 10. A tire rasp blade (10) as claimed in any of Claims 1- 55 ten Zähne (22) jeweils eine Vorderkante und eine 9, further including two mounting holes, one posi- Hinterkante haben; wobei die Vorderkanten der tioned at the midpoint of each of said planar end Zähne (22) eines ebenen Endteils zu der genann- portions. ten ersten Seite des genannten Körpers verscho-

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ben sind und die Vorderkanten der Zähne (22) des incurvées (24, 26), anderen ebenen Endteils zu der genannten zweiten caractérisée en ce que Seite des genannten Körpers verschoben sind. chacune dedites surfaces incurvées (24, 26) délimite une partie d'une ellipse ayant des axes 6. Reifenraspelblatt (10) nach einem der Ansprüche 1 5majeur et mineur inégaux et produit une arête - 4, bei dem die genannte Arbeitskante eine Mehr- de travail sensiblement circulaire (20) lorsque zahl von Zähnen (22) aufweist, die durch eine ladite lame (10) est montée et tourne sur ledit Mehrzahl von bogenförmigen Ausschnitten moyeu. getrennt sind, wobei sich der Scheitel des genannten nicht ebenen Körpers sich an einem Zahn 10 2. Une lame de râpe à pneumatique (10) selon la beﬁndet. Revendication 1, dans laquelle les deux surfaces elliptiques incurvées de ladite arête de travail (20) 7. Reifenraspelblatt (10) nach einem der Ansprüche 1 se coupent audit point milieu. - 6, bei dem der genannte Körper allgemein starr ist. 15 3. Une lame de râpe à pneumatique (10) selon la Revendication 1 ou 2, dans laquelle l'angle que 8. Reifenraspelblatt (10) nach einem der Ansprüche 1 forme chaque partie terminale plate (14, 16) avec - 7, bei dem der genannte Körper formanpassungs- un plan qui coupe perpendiculairement le moyeu fähig und federnd ist. rotatif égale environ 3° ou 4°. 20 9. Reifenraspelblatt (10) nach einem der Ansprüche 1 4. Une lame de râpe à pneumatique (10) selon l'une - 8, bei dem die Arbeitskante induktionsgehärtet ist. quelconque des Revendications 1 à 3, dans laquelle ladite lame (10) est symétrique autour de 10. Reifenraspelblatt (10) nach einem der Ansprüche 1 son point milieu longitudinal. - 9, das des weiteren zwei Befestigungslöcher auf- 25 weist, wobei je eines am Mittelpunkt jedes der 5. Une lame de râpe à pneumatique (10) selon l'une genannten ebenen Endteile angeordnet ist. quelconque des Revendications 1 à 4, dans laquelle ladite arête de travail (20) englobe une plu- 11. Reifenraspelblatt (11) [sic] nach einem der Ansprü- ralité de dents (22), toutes disposées à un angle che 1 - 10, bei dem die genannte Arbeitskante (20) 30 uniforme relativement audit corps de lame ; lesdites eine Mehrzahl von Zähne (22) aufweist, die alle in dents (22) ayant chacune un bord d'attaque et un einem einheitlichen Winkel relativ zum genannten bord de fuite ; lesdits bords d'attaque des dents Blattkörper angeordnet sind, wobei die Zähne (22) (22) de l'une des parties terminales plates étant sich im wesentlichen in der gleichen Ebene beﬁn- déplacés vers ledit premier côté dudit corps et les den wie die für die Achse der Nabendrehung nor- 35 bords d'attaque des dents (22) de l'autre partie ter- male Ebene; wobei die genannten Zähne (22) minale plate étant déplacés vers ledit deuxième jeweils eine Vorderkante und eine Hinterkante côté dudit corps. haben; wobei die Vorderkanten der Zähne (22) eines ebenen Endteils auf eine Seite des genann- 6. Une lame de râpe à pneumatique (10) selon l'une ten Körpers verschoben sind und die Vorderkanten 40 quelconque des Revendications 1 à 4, dans der Zähne (22) des anderen ebenen Endteils auf laquelle ladite arête de travail englobe une pluralité die andere Seite des genannten Körpers verscho- de dents (22) séparées par une pluralité de décou- ben sind. pes en forme d'arc, le sommet dudit corps non plat coïncidant avec une dent. Revendications 45 7. Une lame de râpe à pneumatique (10) selon l'une 1. Une lame de râpe à pneumatique (10) pour utilisa- quelconque des Revendications 1 à 6, dans tion dans une machine à râper les pneumatiques laquelle ledit corps est généralement rigide. qui inclut un moyeu rotatif, englobant : 50 8. Une lame de râpe à pneumatique (10) selon l'une un corps allongé, généralement en forme d'arc quelconque des Revendications 1 à 7, dans et non plat (12) ayant deux parties terminales laquelle ledit corps est conformable et résilient. (14, 16) généralement plates qui ont chacune un premier et un second côté opposés, lesdites 9. Une lame de râpe à pneumatique (10) selon l'une parties terminales (14, 16) généralement pla- 55 quelconque des Revendications 1 à 8, dans tes se coupant en un sommet (18) situé en une laquelle l'arête de travail est trempée par induction. partie milieu dudit corps ; et une arête de travail (20) ayant deux surfaces 10. Une lame de râpe à pneumatique (10) selon l'une

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quelconque des Revendications 1 à 9, qui englobe de plus deux trous de montage respectivement situés au point milieu de chacune desdites parties terminales plates. 5 11. Une lame de râpe à pneumatique (11) [sic] selon l'une quelconque des Revendications 1 à 10, dans laquelle ladite arête de travail (20) englobe une plu- ralité de dents (22), toutes disposées à un angle uniforme relativement audit corps de lame, lesdites 10 dents (22) étant sensiblement dans le même plan que le plan perpendiculaire à l'axe de rotation du moyeu ; lesdites dents (22) ayant chacune un bord d'attaque et un bord de fuite ; les bords d'attaque des dents (22) d'une partie terminale plate étant 15 déplacés vers un côté dudit corps et les bords d'attaque des dents (22) de l'autre partie terminale plate étant déplacés vers l'autre côté dudit corps.

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