ENDLESS POWER TRANSMISSION BELT CONSTRUCTION AND METHOD OF MAKING SAME

Abstract: Endless power transmission belt constructions having power transmitting contact faces, and methods of making the same. The belt constructions (20, 120) comprise an axial tensioning unit (21, 121), a plurality of lateral stiffening units (22, 122) which are carried by the tensioning unit, and friction material (29, 129) carried by at least one of the tensioning unit and stiffening units. The tensioning unit (21, 121) and the stiffening units (22, 122) are formed of a polymeric material that provides an axial and lateral stiffness in excess of that normally provided by polymeric friction material. In one inventive proposal, the friction material (29) is located only at the contact faces of the belt construction, and thereby defines only the contact surfaces (23, 26, 33) of the belt construction, while the tensioning and stiffening units define all other exposed areas of the belt construction. In another embodiment, the friction material (129) has a first portion thereof disposed on the units (121, 122) to define the contact faces (123, 126, 133) thereof, and has a remaining portion thereof disposed on the units to at least assist in securing the first portion to the units. The thickness of the first portion of the friction material (129) is relatively thin, and the thickness of the remaining portion is no thicker than the thickness of the first portion.

Description: ENDLESS POWER TRANSMISSION BELT CONSTRUCTION AND METHOD OF MAKING SAME Technical Field This invention relates to improved endless power transmission belt constructions, as well as to methods of making such belt constructions. Background Art It is known in the art to provide an endless power transmission belt construction having power trans- mitting contact faces, and comprising an axial tension¬ ing means, a plurality of lateral stiffening means carried by the tensioning means, and friction material carried by at least one of the tensioning means or stiff¬ ening means, with the tensioning means and the stiffen- ing means being formed of material that provides an axial and lateral stiffness in excess of that normally provided by polymeric friction material that normally forms the main body of a belt construction that is re¬ inforced with such a tensioning means and stiffening means. Furthermore, the friction material may have a first portion thereof disposed on the means to define the contact faces thereof, and a remaining portion thereof disposed on the means to at least assist in securing the first portion to the means. For example, see the following two United States Patents: (1) U.S. Patent No. 4,078,443 - Warner et al (2) U.S. Patent No. 4,108,012 - Warner et It appears that the power transmission belts of item (1) above have axial tensioning means and lateral stiffening means, which are either formed as a homo¬ geneous one-piece structure, or are separately formed and subsequently secured together, and which are em¬ bedded within a polymeric friction material that normal¬ ly forms the main body of the belt constructions, while the tensioning means and stiffening means reinforce the same. It also appears that the belt constructions in item (2) above each have the lateral stiffening means formed separate from the axial tensioning means while being secured thereto, with at least the axial tension¬ ing means being embedded in polymeric friction material that forms the main body of the belt construction. It is also known to provide metallic lateral stiffening means for a belt construction. For example, see the following U.S. Patent: (3) U.S. Patent No. 4,177,687 - Russ, Sr. It is also known to provide an all metallic belt. For example, see the following U.S. Patentr (4) U.S. Patent No. 3,949,621 - Beusink et al. Disclosure of the Invention It is one feature of this invention to provide an improved endless power transmission belt construction having power transmitting contact faces. It is believed, according to the teachings of this invention, that an endless power transmission belt OMPI IPO construction can be provided by merely providing a "backbone structure" comprising an axial tensioning means and a plurality of lateral stiffening means carried by the tensioning means (with the means being formed of material that provides an axial and lateral stiffness in excess of that normally provided by poly¬ meric friction material that normally forms the main body of the belt construction that is reinforced with such a tensioning means and stiffening means, such as in the aforementioned U.S. Patent to Warner et al, No. 4,078,443), and then utilizing such "backbone structure" as the main body of the belt construction itself by either merely applying the friction material at the power transmitting contact faces of the belt construc- tion, so that the friction material only defines the contact faces while the "backbone structure" defines all other exposed areas of the belt construction, or by merely applying a relatively thin layer of the friction material to the "backbone structure" at the power trans- mitting contact faces of the belt construction, so that the friction material defines the contact faces, and at other parts of the "backbone structure" to at least assist in securing the friction material thereto, where¬ by the "backbone structure" defines substantially all of the material of the belt construction. Thus, it is believed that while the U.S. Patents to Warner et al, No. 4,078,443 and No. 4,108,012, MPI provide a "backbone structure", the patentees did not appreciate the fact that that "backbone structure" could be utilized as the belt construction itself, and that the friction material need not form the main body part of the belt construction as in such patents, and that the friction material need only be applied to the contact faces of the power transmission belt to define only those contact faces thereof, while the "backbone structure" defines all other exposed areas of the belt construction as provided by applicant's invention in order to reduce the heat of operation of the resulting belt construction, as will be hereinafter set forth. Nor did the above-referenced patentees appreciate the fact that the "backbone structure" could be utilized as the belt construction itself, and that the friction material need not form the main body part of the belt construction as in such patents, and that the friction material need only be applied in a relatively thin layer to the "backbone structure" at the contact faces of the power transmission belt to define those contact faces thereof, and to other parts to secure the layers thereto, whereby the "backbone structure" defines sub¬ stantially all the material of the belt construction as provided by applicant's invention in order to again re- duce the heat of operation of the resulting belt con¬ struction, as will be hereinafter set forth. Pursuant to one aspect of this invention, there is provided an endless power transmission belt construc¬ tion having power transmitting contact faces, and com¬ prising an axial tensioning means, a plurality of lateral stiffening means which are carried by said tensioning means, and friction material carried by at least one of said tensioning means and said stiffening means; said tensioning means and said stiffening means are formed of polymeric material that provides an axial and lateral stiffness in excess of that normally provided by polymeric friction material that normally forms the main body of a belt construction that is re¬ inforced with such a tensioning means and stiffening means; said stiffening means and said tensioning means are formed of the same material and comprise a one- piece construction; the improvement wherein said fric¬ tion material is located only at said contact faces and thereby defines only said contact faces of said belt construction, while said tensioning means and said stiffening means define all other exposed areas of said belt construction. Pursuant to another aspect of this invention, there is provided an endless power transmission belt construction having power transmitting contact faces, and comprising an axial tensioning means, a plurality of lateral stiffening means which are carried by said tensioning means, and friction material, such as poly¬ meric material, which is carried by said means; said " ■ dϋREA OMPI tensioning means and said stiffening means are formed of material that provides an axial and lateral stiff¬ ness in excess of that normally provided by polymeric friction material that normally forms the main body of a belt construction that is reinforced with such a tensioning means and stiffening means; the friction material has a first portion thereof disposed on said means to define said contact faces thereof, and has a remaining portion thereof disposed on said means to at least assist in securing said first portion to said means; the improvement wherein the thickness of said first portion of said friction material is relatively thin, and the thickness of said remaining portion is no thicker than the thickness of said first portion, whereby a substantially large amount of said belt con¬ struction comprises said material of said tensioning means and said stiffening means, and a substantially small amount of said belt construction comprises said friction material. Accordingly, it is an object of this invention to provide improved endless power transmission belt constructions having one or more of the novel features of this invention as set forth above or hereinafter shown or described. Another object of this invention is to provide method of making such endless power transmission belt constructions, the methods of this invention having one or more of the novel features of this invention as set forth above or hereinafter shown or described. Brief Description of the Drawings The features of the invention,' and its technical advantages, can be seen from the following description of preferred embodiments, together with the claims and the accompanying drawings, in which: FIG. 1 is a fragmentary perspective view of one embodiment of the endless power transmission belt construction of this invention; FIG. 2 is a fragmentary side view of the belt construction of FIG. 1; FIG. 3 is an enlarged cross-sectional view taken on line 3-3 of FIG. 1; FIG. 4 is a fragmentary side view of an¬ other embodiment of the belt construction of this in¬ vention; FIG. 5 is a fragmentary side view of an¬ other embodiment of the belt construction of this in- vention; FIG. 6 is an enlarged cross-sectional view taken on line 6-6 of FIG. 5; FIG. 7 is a fragmentary perspective view of another embodiment of the belt construction of this invention; FIG. 8 is a fragmentary perspective view of a further embodiment of the endless power transmission , belt construction of this invention; FIG. 9 is a fragmentary side view of the belt construction of FIG. 8; FIG. 10A is an enlarged 'cross-sectional view taken on line 10A-10A of FIG. 8; FIG. 10B is an enlarged cross-sectional view taken on line 10B-10B of FIG. 8; FIG. 11 is a fragmentary side view of an¬ other embodiment of the belt construction of this in- vention; FIG. 12 is a fragmentary side view of another embodiment of the belt construction of this invention; FIG. 13A is an enlarged cross-sectional view taken on line 13A-13A of FIG. 12; FIG. 13B is an enlarged cross-sectional view taken on line 13B-13B of FIG. 12; and FIG. 14 is an enlarged fragmentary cross- sectional view of another embodiment of the belt con- struction of this invention. Best Modes for Carrying Out the Invention While the various features of this invention are hereinafter illustrated and described as pro¬ viding power transmission belt constructions, such as a V-belt construction for a variable pulley drive, a toothed belt construction for timing or synchronous purposes, etc., it is to be understood that the various features of this invention can be utilized singly or in various combinations thereof to pro¬ vide belt constructions for other purposes. Therefore, this invention is not to be limited to only the embodiments illustrated in the drawings, because the drawings are merely utilized to illustrate some of the wide variety of uses of this invention. Referring now to FIGS. 1-3, one improved endless power transmission belt construction of this invention is generally indicated by the reference numeral 20. The belt 20 comprises an axial tensioning means 21, and a plurality of lateral stiffening means 22 which are carried by the axial tensioning means 21 and co¬ operate therewith to define power transmitting contact faces 23 on the opposed ends 24 and 25 of the stiffen¬ ing means 22, and power transmitting contact faces 26 on the opposed ends 27 and 28 of the axial tensioning means 21. The belt construction 20 further comprises friction material 29 which is disposed only on the end faces 23 of the stiffening means 22 and on the edge faces 26 of the axial tensioning means 21. The fric¬ tion material 29 defines only the power transmitting contact faces of the belt construction, while the axial tensioning means 21 and the stiffening means 22 define all other exposed areas of the belt construction 20. The axial tensioning means 21 is illustrated as being an annular flat band, and the stiffening means 22 are illustrated as being cylindrical in configura¬ tion. However, it is to be understood that the axial tensioning means 21 can have any desired and suitable cross-sectional configuration, and the stiffening means 22 can likewise have any desired and suitable cross-sectional configuration, as well as varied cross- sectional configurations; the important feature is that the axial tensioning means 21 and the lateral stiffen¬ ing means 22 define a "backbone structure" for the belt construction 20. In addition, the stiffening means 22 can be formed separate from the axial tensioning means 21, and can be subsequently secured thereto in any desired manner. Alternatively, the axial tensioning means 21 and the lateral stiffening means 22 can be formed to¬ gether to provide a homogeneous and one-piece structure. For example, such one-piece structure can be provided by an injection molding operation in a manner well known in the art. The axial tensioning means 21 and the lateral stiffening means 22 of this invention are formed of any suitable material that provides an axial and lateral stiffness in excess of that normally provided by polymeric friction materials that normally form the main body of a belt construction that is reinforced with such a tensioning means and stiffening means. In this regard, it is believed that the means 21 and OMFI 22 can be formed of polymeric material, metal, etc., or combinations of material, with the material of the axial tensioning means 21 being the same as or differ¬ ent than the material of the lateral 'stiffening means 22. For example, such combination of materials is disclosed in the aforementioned U.S. Patents to Warner et al, No. 4,078,443 and No. 4,108,012, whereby these two patents are being incorporated into this disclosure by this reference thereto, not only for a description of suitable materials, but also for the description of forming belt construction by injection molding, etc., whereby the details of injection molding, etc., for forming the belt constructions of this invention need not be further discussed in this application. The belt construction 20 of this invention is a V-belt construction as illustrated in FIG. 3. The end faces 23 of the lateral stiffening means 22, and the end faces 26 of the axial tensioning means 21, are shaped in such a way as to define the substantially trapezoidal ^ cross-sectional configuration illustrated in FIG. 3. The friction material 29 defines the power transmitting angled contact faces of the V-belt con¬ struction of FIG. 3. Because the axial tensioning means 21 and the lateral stiffening means 22 extend to the angled sides 29' illustrated in FIG. 3, it is believed that the belt construction 20 could be utilized for continuously variable transmission purposes . While the friction material 29 can comprise any suitable friction material, such as rubber, fabric, brake facing material, clutch facing material, etc., and combinations of such material, it is believed according to the teachings of this invention that because such friction material 29 is provided only at the contact faces of the belt construction 20 of this invention, hysteretic heat build up due to the repeat- ed flexing of the frictional material 29 during the ■ use of the power transmission belt construction 20 is substantially minimized as compared to the heat build up rate of conventional polymeric belt constructions under the same operating conditions. Thus, it is believed that providing the friction material 29 to form the main body part of the belt construction 20, as in the aforementioned U.S. Patents to Warner et al, would result in the friction material 29 providing too great of a heat build up due to the continuous flexing of such friction material 29 as in the patents to Warner et al, whereby it is be¬ lieved that the patents to Warner et al did not appre¬ ciate the fact thatthe amount of friction material 29 can be held to an absolute minimum by disposing the same only at the power transmitting contact faces of the "backbone structure" of a composite belt construc¬ tion, so that the "backbone structure" itself forms the OMPI main body of the belt construction as provided by this invention. If desired, a reinforcing cord or cords 30 can be helically wound during the injection molding of the axial tensioning means 21 to be completely encapsu¬ lated therein. The cord 30 is of any suitable materi¬ al, such as a material normally forming the cords of power transmission belts or the like. For example, the cord or cords 30 can be provided in the same man- ner as set forth in the aforementioned U.S. Patent to Warner et al, No. 4,078,443 at the same time that the axial tensioning means 21 is being injected mold¬ ed, with or without the stiffening means 22 being in¬ jection molded therewith, as the case may be. In any event, it can be seen that the axial ten¬ sioning means or band 21 prevents the helically wound cord or cords 30 from projecting out of the side edges 26 thereof as in conventional belt constructions which have edge cords coming out of the sides of such cover- less belt constructions. However, it is to be understood that it is be¬ lieved that the material of the axial tensioning means 21 itself could provide the sole axial strength for the belt construction 20 with or without the encapsu- lated cord or cords 30, and could also encapsulate re¬ inforcing fibers or other structure, as desired. As previously stated, while the lateral stiff- ening means 22 can have , any cross-sectional configura¬ tion, it can be seen in FIGS. 1 and 2 that the lateral stiffening means 22 respectively extend from the out¬ side surface 31 of the axial tensioning means 21, as well as from the inside surface 32 thereof. The lateral stiffening means 22 that extend from the out¬ side surface 31 of the axial tensioning means 21 are in radial alignment with the lateral stiffening means 22 that extend from the inside surface 32 thereof. However, it is to be understood that the lateral stiff¬ ening means 22 could extend from the axial tensioning means 21 in offset relation relative to the outside and inside surfaces 31 and 32 thereof, as provided by the belt construction 20A illustrated in FIG. 4, or could extend from only one side 31 or 32 of the axial tensioning means 21, as provided by the belt construc¬ tion 20B of FIGS. 5 and 6. In addition, while the axial stiffeners 22 are illustrated as extending sub¬ stantially to the side faces 26 of the axial tensioning means 21 for the belt construction 20, it is to be understood that the axial stiffness 22 could extend beyond the side faces 26 in the manner provided by the belt construction 20C of FIG. 7. Accordingly, the parts of the belt constructions 20A, 20B, and 20C that are similar to like parts of the belt construction 20 are indicated in the drawing by the same reference numerals, followed by the respective reference letter "A", "B", or "C". In particular, the belt construction 20A of FIG. 4 is substantially the same as the belt construction 20 of FIGS. 1-3, except that the lateral stiffening means 22A that extend outwardly from the side 31A of the belt construction 20A are disposed in offset radial relation to the axial stiffening means 22A that extend inwardly from the inside surface 32A of the axial ten¬ sioning means 21A as illustrated. While the inside stiffening means 22A of the belt construction 20A are disposed medially between a pair of outside axial stiffeners 22A, it is to be understood that the inside stiffeners 22A could be arranged in any desired pattern relative to the pat- tern of the outside stiffeners 22A, as desired. In any event, the end faces 23A of the stiff¬ eners 22A, and the end faces 26A of the axial ten¬ sioning means 21A, are provided with frictional material 29A, so that the frictional material 29A is disposed only on the power transmitting contact faces of the belt construction 20A for the reasons previous¬ ly set forth in connection with the belt construction 20. The belt construction 20B of this invention illustrated in FIGS. 5 and 6 has the lateral stiffen¬ ers 22B extending only from the inside surface 32B of the axial tensioning means 2IB. Each stiffener has a cross-sectional configuration that is sub¬ stantially trapezoidal to define a tooth having power transmitting contact faces 33 against which the fric¬ tional material 29B is secured, so that the friction material 29B is disposed only on the selected areas 33 of the belt construction 20B to only define the contact faces 33B thereof, whereby the remainder of the exposed areas of the belt construction 20B is provided by the exposed surfaces of the axial ten- sioning means 21B and the stiffening means 22B. Thus, it can be seen that the bely construction 20B com¬ prises a toothed belt which transmits its driving force by having its teeth 22B engaging with suitable gear teeth-like structure in a manner well known in the art. Therefore, it can be seen that by making the major portion of the teeth 22B out of stronger materi¬ al than the friction material 29B, and by making the teeth 22B integral with the band 21B in the manner previously described, it is believed that shearing of the teeth 22B is less likely than when the teeth of a belt construction are formed substantially entirely of friction material. In regards to the belt construction 20C illus- trated in FIG. 7, it can be seen that the lateral stiffeners 22C thereof have the opposed ends 24C and 25C thereof extending beyond the side faces 26C of the axial tensioning means 21C, so that the side faces 26C of the axial tensioning means 21C do not form any part of the power transmitting contact faces thereof, whereby the friction material 29C is only disposed on the end faces 23C of the stiffening means 22C. Therefore, it can be seen that each of the previously described and illustrated belt construc¬ tions 20, 20A, 20B, and 20C of this invention has power transmitting contact faces, and comprises an axial tensioning means, a plurality of lateral stiff¬ ening means carried by the tensioning means, and fric¬ tion material carried by such means; the tensioning means and the stiffening means are formed of material that provides an axial and lateral stiffness in excess of that normally provided by polymeric friction materi¬ al that normally forms the main body of a belt con¬ struction that is reinforced with such a tensioning means and stiffening means. The friction material is only provided on selected areas of such means, so that all of the friction material is located only at the contact faces of the belt construction, and thereby defines only the contact faces of the belt construc¬ tion, while such means define all other exposed areas of the belt construction. Referring now to FIGS. 8, 9, 10A, and 10B, an¬ other improved endless power transmission belt con¬ struction of this invention is generally indicated by the reference numeral 120. The belt 120 comprises an axial tensioning means 121, and a plurality of lateral stiffening means 122 which are carried by the axial tensioning means 121 and cooperate therewith to define power transmitting contact faces 123 on the opposed ends 124 and 125 of the stiffening means 122, and pow¬ er transmitting contact faces 126 on the opposed ends 127 and 128 of the axial tensioning means 121. The belt construction 120 further comprises friction mate- rial 129 which is disposed in a relatively thin layer on the means 121 and 122 to fully encapsulate the same. The friction material 129 has a first portion thereof disposed on the end faces 123 of the stiffening means 122 and on the edge faces 126 of the axial tensioning means 121 to define the power transmitting contact faces of the belt construction; the remaining portion of the friction material 129 at least assists in se¬ curing the friction material 129 to the means 121 and 122. The axial tensioning means 121 and the stiffen- ing means 122 define substantially a large amount of the material of the belt construction 120, and the friction material 129 defines a relatively small amount of the material of the belt construction 120. Again, as with the previously described em- bodiments, the axial tensioning means 121 is illus¬ trated as being an annular flat band, and the stiffen¬ ing means 122 are illustrated as being cylindrical in OMPI v~.ro configuration. However, it is to be understood that the configurations of these means are in no way re¬ stricted to those illustrated, and that they can have any desired and suitable cross-sectional configuration. Furthermore, the previous discussion concerning the formation of, and the material for, the stiffening means 22 and the tensioning means 21, also applies to the formation of, and the material for, the stiffening means 122 and the tensioning means 121. In a manner similar to the belt construction 20, the belt construction 120 is a V-belt construction as illustrated in FIGS. 10A and 10B. Again similar to the discussion in connection with the previous embodiments, it is believed accord- ing to the teachings of this invention that because such friction material 129 is provided only in a relatively thin layer that is no thicker on the non- contact face portions of the means 121 and 122 than is the relatively small thickness of the portion thereof at the contact faces of the belt construction 120 of this invention, hysteretic heat build up due to the repeated flexing of the frictional material 129 during the use of the power transmission belt con¬ struction 120 is substantially minimized as compared to the heat build up rate of conventional polymeric belt constructions under the same operating conditions. Again, it is believed that the patents to Warner et al did not appreciate the fact that the amount of friction material 129 can be held to an absolute mini¬ mum by disposing the same only in a relatively thin layer on the "backbone structure" of a composite belt construction, so that the "backbone structure" itself forms the main body of the belt construction as pro¬ vided by this invention. It is to be understood that the friction materi¬ al 129 can be disposed on the "backbone structure" 121, 122 in any suitable manner, such as by injection mold¬ ing the material 129 onto the preformed "backbone structure" 121, 122, by merely dipping the preformed "backbone structure" in molten friction material, etc. If desired, a reinforcing cord or cords 130 can be provided in a manner similar to that previously dis¬ cussed. As previously stated, while the lateral stiffen¬ ing means 122 can have any cross-sectional configura¬ tion, it can be seen in FIGS. 8 and 9 that the later- al stiffening means 122 respectively extend from the outside surface 131 of the axial tensioning means 121, as well as from the inside surface 132 thereof. The lateral stiffening means 122 that extend from the out¬ side surface 131 of the axial tensioning means 121 are in radial alignment with the lateral stiffening means 122 that extend from the inside surface 132 thereof. However, it is to be understood that the lateral stiffening means 122 could extend from the axial ten¬ sioning means 121 in offset relation relative to the outside and inside surfaces 131 and 132 thereof, as provided by the belt construction 120A illustrated in FIG. 11, or could extend from only one side 131 or 132 of the axial tensioning means 121, as provided by the belt construction 120B of FIGS. 12 and 13. In addi¬ tion, while the friction material 129 has been describ¬ ed and illustrated as completely encapsulating the "backbone structure" 121, 122, it is to be under¬ stood that the friction material can merely encapsu¬ late part of the "backbone structure" 121, 122, such as only encapsulating all or part of just the stiffen- ing means 122 in the manner provided by the belt con- struction 120C of FIG. 14. Accordingly, the parts of the belt construction 120A, 120B, and 120C that are similar to like parts of the belt construction 120 are indicated in the drawing by the same reference numerals, followed by the re- spective reference letter "A", "B", or "C". In particular, the belt construction 120A of FIG. 11 is substantially the same as the belt con¬ struction 120 of FIGS. 8 and 9, except that the later¬ al stiffening means 122A that extend outwardly from the side 131A of the belt construction 120A are dis¬ posed in offset radial relation to the axial stiffen¬ ing means 122A that extend inwardly from the inside surface 132A of the axial tensioning means 121A as illustrated. While the inside stiffening means 122A of the belt construction 120A are disposed ' medially between a pair of outside axial stiffeners 122A, it is to be understood that the inside stiffeners 122A could be arranged in any desired pattern relative to the pat¬ tern of the outside stiffeners 122A, as desired. In any event, the end faces 123A of the stiffen- ers 122A, and the end faces 126A of the axial tension¬ ing means 121A, are provided with frictional material 129A, so that the frictional material 129A is disposed on the power transmitting contact faces of the belt construction 120A for the reasons previously set forth in connection with the belt construction 120. The belt construction 120B of this invention illustrated in FIGS. 12, 13A, and 13B has the lateral stiffeners 122B extending only from the inside surface 132B of the axial tensioning means 121B. Each stiff- ener 122B has a cross-sectional configuration that is substantially trapezoidal to define a tooth having power transmitting contact faces 133 against which the frictional material 129B is secured. The friction material 129B also completely encapsulates the "back- bone structure" 121B, 122B in a thin layer thereof in the same manner as in the belt constructions 120 and 120A, so that the friction material 129B is not only OMPI_ \vIT-0 , disposed on the selected areas 133 of the belt con¬ struction 120B to define the contact faces 133 thereof, but also is disposed on the remainder of the "backbone structure" 12IB, 122B to at least assist in securing the friction material 129B thereto. Thus, it can be seen that the belt construction 120B comprises a tooth¬ ed belt which transmits its driving force by having its teeth 122B engaging with suitable gear teeth-like structure in a manner well known in the art. Therefore, it can be seen that by making the major portion of the teeth 122B out of stronger materi¬ al than the friction material 129B, and by making the teeth 122B integral with the band 12IB in the manner previously described, it is believed that shearing of the teeth 122B is less likely than when the teeth of a belt construction are formed substantially entirely of friction material. In regards to the belt construction 120C illus¬ trated in FIG. 14, it can be seen that only the later- al stiffeners 122C thereof have the friction material 129C encapsulated thereon. If desired, the stiffeners 122C can have opposed ends 124C and 125C (not shown) thereof extending beyond the side faces 126C of the axial tensioning means 121C, so that the side faces 126C of the axial tensioning means 121C do not form any part of the power transmitting contact faces there¬ of, whereby the friction material 129C is only disposed on the* end faces 123C of the stiffening means 122C at the side edges of the belt construction 120C. Therefore, it can be seen that each of the pre¬ viously described and illustrated belt constructions 120, 120A, 120B, and 120C of this invention has power transmitting contact faces, and comprises an axial ten¬ sioning means, a plurality of lateral stiffening means carried by the tensioning means, and friction material carried by such means; the tensioning means and the stiffening means are formed of material that provides an axial and lateral stiffness in excess of that normal¬ ly provided by polymeric friction material that normally forms the main body of a belt construction that is re¬ inforced with such a tensioning means and stiffening means. The friction material has a first portion thereof disposed on the means to define the contact faces thereof, and has a remaining portion thereof dis¬ posed on the means to at least assist in securing the first portion to the means. The thickness of the first portion of the friction material is relatively thin, and the thickness of the remaining portion is no thick¬ er than the thickness of the first portion, whereby a substantially large amount of the belt construction comprises the material of the means, and a substantially small amount of the belt construction comprises the friction material. Accordingly, it can be seen that this invention not only provides improved endless power transmission belt constructions, but also this invention provides methods of making such improved endless power trans¬ mission belt constructions. While the forms and methods of this invention now preferred have been illustrated and described as required, it is to be understood that other forms and method steps can be utilized and still fall within the scope of the appended claims.

Claims: AMENDED CLAIMS [received by the International Bureau on 09 October 1984 (09.10.84); claim 12 added (2 pages)] comprises said material of said tensioning means and said stiffening means, and a substantially small amount of said belt construction comprises said friction material. > 12. A method of making an endless power transmission belt construction having power trans¬ mitting contact faces, said method comprising the steps of forming an axial tensioning means, forming a plurality of lateral stiffening means which are carried by said tensioning means, forming friction material that is carried by said stiffening means and said tensioning means, forming said tensioning means and said stiffening means from material that pro- vides an axial and lateral stiffness for said belt construction and thereby provides a backbone structure for said belt construction, and forming said friction material to have a first portion thereof disposed on said backbone structure to define said contact faces and to have a remaining portion thereof disposed on said backbone structure to at least assist in securing said first portion to said backbone structure; the improve¬ ment characterized in that said steps of forming said friction material comprise the step of dipping said backbone structure in said friction material while said friction material is in a liquid condition so as to form the thickness of said first portion of said friction material to be relatively thin, and the OMPI thickness of said remaining portion to be no thicker than the thickness of said first portion, whereby a substantially large amount of said belt construction comprises said backbone structure, and a substantially small amount of said belt construction comprises said friction material.

Inventors: OLIVER LARRY R, OLIVER, LARRY, R.
Applicants: DAYCO CORP, DAYCO CORPORATION
Application year: 1984
Main classification: F16G1
IPC codes: B29D29, B29K105, B32B27, F16G1, F16G5