BELT CONSTRUCTION AND METHOD OF MAKING THE SAME

Abstract: A belt construction and method of making the same are provided. The belt construction (10) com­ prises: a tensile member (13) intermediate the opposed sides (11, 12) of the belt construction; a plurality of teeth (14) defining one (12) of the opposed sides of the belt construction and being mainly formed of a first polymeric material (16) that has reinforcing fibers (17) therein, each tooth (14) having opposed sides (18, 19) that are disposed in spaced relation to adjacent sides of adjacent teeth, the belt con­ struction having a land area (20) between adjacent teeth; and a backing member (15) defining the other (11) of the opposed sides of the belt construction, the backing member being mainly formed from a second polymeric material (21) that is initially separate from the material (16) of the teeth and is substantially free of fibers therein, the material of the backing member (15) having a surface (22) that joins with a surface (23) of each tooth (14), whereby the joining surfaces define an interface line (24) therebetween, the interface line for each tooth extending from the tensile member (13) at a point (26) inboard of one (18) of the opposed sides of the respective tooth into the medial portion (27) of the respective tooth and then back to the tensile member (13) at a point (28) in­ board of the other (19) of the opposed sides of the respective tooth, whereby part (29) of the material (21) of the backing member (15) defines part of the medial portion (27) of each tooth, the surface (22) of the backing member (15) also joining with a surface (30) of the first material (16) in each land area (20), whereby the joining surfaces in each land area define an interface line (31) therebetween, the interface line in each land area having a portion (32) thereof disposed spaced from the tensile member (13) on the side (33) thereof opposite to the side (25) thereof that faces toward the teeth (14).

Description: Technical Field This invention relates to a method of making an improved belt construction. Background Art It is known to provide a belt construction having opposed sides and comprising: a tensile member intermediate the opposed sides; a plurality of teeth defining one of the opposed sides of the belt construction and being mainly formed of a first polymeric material that has reinforcing fibers therein, each tooth having opposed sides that are disposed in spaced relation to adjacent sides of adjacent teeth, the belt construction having a land area between adjacent teeth; and a backing member defining the other of the opposed sides of the belt construction, the backing member being mainly formed from a second polymeric material that is initially separate from the material of the teeth and is substantially free of fibers therein, the material of the backing member having a surface that joins with a surface of each tooth, whereby the joining surfaces define an interface line therebetween, the interface line for each tooth extending from the tensile member at a point inboard of one of the opposed sides of the respective tooth into the medial portion of the respective tooth and then back to the tensile member at a point inboard of the other of the opposed sides of the respective tooth, whereby part of the material of the backing member defines part of the medial portion of each tooth, the surface of the backing member joining with a surface of the first material in each land area, whereby the joining surfaces in each land area define an interface line therebetween. For example, see the U.S. Patent to Wetzel, No. 4,235,119. It is also known to form a belt construction that has teeth on one side thereof by providing a grooved drum, disposing a tensile member about the drum, then disposing a polymeric backing material about the tensile member, and then subjecting the drum to heat and pressure to cause the material to be forced toward the drum, whereby the material exudes through the tensile member adjacent the grooves and enters the grooves to form the belt teeth. For example, see the U.S. Patent to Skura, No. 3,078,206. While the U.S. Patent to Miller, No. 3,535,946, does not state that the backing material thereof is formed of a plurality of layers that are initially separate and are respectively exuded through the tensile member in the same manner as the aforementioned Patent to Skura, No. 3,078,206, FIG. 3 of the Patent to Miller illustrates an interface line between fiber-containing material and non-fiber containing material that extends from a point in the land area of the belt construction that is spaced beyond one side of the tensile member and into each tooth beyond the other side of the tensile member before returning back to the next adjacent land area. Disclosure of the Invention This invention relates a method of making an improved belt construction wherein the teeth thereof are less likely to be sheared therefrom along the tensile member of such belt construction. To have a better understanding of the present invention and of how it can be embodied, it can be referred to JP-A-55-57741. In this respect the common features between the prior document and the method of the present invention have been mentioned in the preamble of claim 1, while the improvement over the art has been stated in the characterizing part of this claim. Sub-claims 2-8 directly dependent on claim 1 concern particular steps of the method of claim 1. 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 an enlarged, fragmentary, cross-sectional view illustrating one embodiment of the improved belt construction produced by the method of this invention; FIG. 2 is a schematic, broken away, perspective view illustrating the apparatus and method of this invention for forming the belt construction of FIG. 1; FIG. 3 is an enlarged, fragmentary, cross-sectional view taken on line 3-3 of FIG. 2; FIG. 3 illustrates one step in the method of this invention for forming the belt construction of FIG. 1; FIG. 4 is a view similar to FIG. 3, and illustrates another step in the method of this invention for forming the belt construction of FIG. 1; Referring now to FIG. 1, one embodiment of the improved belt construction produced by the method of this invention is generally indicated by the reference numeral 10. The belt construction 10 has opposed sides 11 and 12, and comprises a tensile member or means 13 disposed intermediate the opposed sides 11 and 12, a plurality of teeth that are generally indicated by the reference numeral 14 and define the side 12 of the belt construction, and a backing member 15 which defines the side 11 of the belt construction. While the tensile section 13 of the belt construction 10 can comprise any suitable structure, the embodiment thereof illustrated in the drawings comprises a plurality of side-by-side cord strands formed of substantially non-stretchable polymeric material in a manner conventional in the belt making art, as will be apparent hereinafter; therefore, the term "tensile member" will be hereinafter utilized for describing the tensile section 13 of the belt construction 10. The teeth 14 of the belt construction 10 are mainly formed of a first polymeric material 16 that has reinforcing fibers 17 therein. Each tooth 14 has opposed sides 18 and 19 that are disposed in spaced relation to adjacent sides 19 and 18 of adjacent teeth 14. The sides 18 and 19 of each tooth 14 are shown as being flat and angled relative to the longitudinal axis of the belt construction 10, which axis is disposed parallel to the tensile member 13. The sides 18 and 19 can comprise the driving or driven parts of the teeth 14 in a manner well known in the art. However, it is to be understood that the cross-sectional configuration of the teeth 14 can have any other suitable profile, rather than being substantially trapezoidal as illustrated in FIG. 1, if desired. The belt construction 10 has land areas that are generally indicated by the reference numeral 20 in FIG. 1, and are respectively disposed between adjacent teeth 14 as is conventional in the art. The backing member 15 of the belt construction 10 is mainly formed from a second polymeric material 21 that is initially separate from the material 16 of the teeth 14, and is substantially free of reinforcing fibers therein. The material 21 of the backing member 15 has a surface 22 that joins with a surface 23 of each tooth, whereby the joining surfaces 22 and 23 define an interface line 24 therebetween. The interface line 24 for each tooth 14 extends from one side 25 of the tensile member 13, at a point 26 inboard of the opposed side 18 of the respective tooth 14, into the medial portion of the respective tooth 14 (generally indicated by the reference numeral 27), and then back to the side 25 of the tensile member 13 at a point 28 that is inboard of the other opposed side 19 of the respective tooth. In this manner, a part 29 of the material 21 of the backing member 15 defines part of the medial portion 27 of each tooth 14. The interface line 24 for each tooth 14 is substantially arcuate between the points 26 and 28 thereof in a manner similar to the interface line for each tooth of the belt construction set forth in the aforementioned U.S. patent to Wetzel, No. 4,235,119, whereby this patent is being incorporated into this disclosure by this reference thereto. The surface 22 of the backing member 15 also joins with a surface 30 of the first material 16 in each land area 20, whereby the joining surfaces 22 and 30 in each land area 20 define an interface line 31 therebetween. The interface line 31 in each land area 20 of the belt construction 10 produced by the method of this invention has a portion 32 that is disposed spaced from the side 33 of the tensile member 13 and is generally parallel thereto. The interface line 31 of each land area 20 joins with the interface lines 24 of each tooth 14 adjacent thereto by a portion 34 thereof that extends between the opposed sides 25 and 33 of the tensile member 13 through the spaces between adjacent cord strands of the tensile member 13, as will be apparent hereinafter. The interface line 31 has opposed arcuate portions 35 in each land area 20 which join the substantially straight portion 32 thereof with the opposed intermediate portions 34 thereof as illustrated. In this manner, it can be seen that the interface line 24 for each tooth 14 of the belt construction 10 produced by the method of this invention, as well as the major portion 32 of the interface line 31 for each land area 20 of the belt construction 10, are disposed spaced from the tensile member 13, thus removing any tendency of a shearing effect to take place at such interface lines 24 and 31 along the tensile member 13, since the only portions of the interface lines 24 and 31 between the materials 16 and 21 that actually engage the tensile member 13 are at 34 and are disposed at an angle relative to the longitudinal axis of the tensile member 13 and, thus, would oppose any shearing forces being applied to the teeth 14 during the driving or driven operation of the belt construction 10 in a manner that is well known in the art. If desired, a conventional reinforcing fabric material 36 can be utilized to cover the opposed sides 18 and 19 of each tooth 14, as well as to cover the bottom surfaces 37 of each tooth 14 and the bottom surface 38 of each land area 20, as illustrated in FIG. 1. It has been found according to the teachings of this invention that the belt construction 10 illustrated in FIG. 1, and previously described, can be formed by utilizing a method and apparatus similar to the method and apparatus disclosed and described in the aforementioned U.S. Patent to Skura, No. 3,078,206, and the aforementioned U.S. Patent to Miller, No. 3,535,946 whereby these two patents are being incorporated into this disclosure by this reference thereto. For example, reference is now made to FIGS. 2 and 3, wherein the method and apparatus of this invention for making the belt construction 10 of FIG. 1 is generally indicated by the reference numeral 40, and comprises a drum 41 that has a plurality of longitudinally disposed and spaced apart parallel grooves 42 therein; the teeth 14 of the belt construction 10 are subsequently formed in these grooves 42. The grooves drum 41 is formed and operated substantially in the same manner as set forth in the aforementioned patent to Skura, No. 3,078,206; therefore, the details thereof need not be set forth. However, when forming the belt construction 10 of this invention, the stretchable fabric cover 36 is first disposed about the drum 41, with the opposed ends of the fabric cover 36 either being butt joined or overlapped as desired, with the butt joint or overlapping of the fabric material 36 taking place along an ungrooved portion 43 of the drum 41 in a conventional manner. Thereafter, the tensile member 13 is disposed on top of the fabric covering 36 by suitably winding one or more cords on the fabric covering; adjacent turns 44 of the tensile member 13 are spaced from each other the desired distance or combinations of distances, with FIG. 2 merely being a schematic showing of such spacing which will permit the polymeric material 16 and 21 to exude therethrough. Thereafter, a layer of the first polymeric material 16 is disposed about the drum 41 on top of the tensile member 13, with the opposed ends 45 and 46 thereof being disposed in abutting relation as represented by the butt line 47 in FIG. 2. While the fibers 17 in the polymeric material 16 could be randomly and homogeneously disposed therein, it is preferred that the fibers 17 are oriented throughout the material 16. In the embodiment illustrated in FIGS. 1 and 2, the fibers 17 in the material 16 have been oriented in such a way that their long dimensions will mainly extend in a direction between the opposed sides 18 and 19 of each tooth 14, as illustrated in FIG. 1, and therefore are disposed in a direction that is transverse to the longitudinal direction of the drum 41, as illustrated in FIG. 2. Thereafter, a layer of the second polymeric material 21 is disposed about the drum 41 on top of the first polymeric material 16. The layer of polymeric material 21 has the opposed ends 48 and 49 thereof disposed in abutting relation, as represented by the butt line 50 in FIG. 2. After the parts 36, 13, 16 and 21 of the belt construction 10 have been disposed in the wrapped around connection on the drum 41 as illustrated in FIGS. 2 and 3, a collapsible jacket (not shown) is disposed around the same and the jacket-wrapped drum 41 is disposed in a pressure chamber wherein heat and pressure are applied against the surrounding jacket, as well as inside the drum 41, to not only heat the material 36, 13, 16 and 21, but also to force the material 16 and 21 toward the drum 41 in such a manner that the material 16 and 21 will form a belt sleeve, from which the individual belt constructions 10 can be subsequently cut. This belt sleeve is formed in the manner illustrated in FIG. 4 by having the covering material 36 stretched and forced into the grooves 42 to outline the grooves 42 of the drum 41 as the heated material 16 exudes through the tensile member 13 and substantially fills the grooves 42 together with the part 29 of the material 21 that also exudes through the tensile member 13 to complete the medial portion 27 of each tooth 14 in the manner illustrated in FIG. 4. Such heating and compressing of the material 21 and 16 causes the interface lines 24 and 31 to form in the manner previously described, and for the previously described purpose, as well as to cure and secure the initially separate and uncured materials 16, 21 and 36 into a completed belt sleeve as is well known in the belt making art. Thus, it can be seen that the method and apparatus set forth in the aforementioned U.S. Patent to Skura, No. 3,078,206, can be utilized to form the belt construction 10 of this invention by uniquely disposing the layers 36, 13, 16 and 21 around the drum 41 and then applying heat and pressure to form the belt sleeve which will be cured in the condition illustrated in FIG. 4, so that individual belts 10 can be subsequently cut from the resulting belt sleeve before or after the same has been removed from the drum 41 in a manner well known in the art. As previously stated, any suitable polymeric material or materials can be utilized for forming the layers 16 and 21, as well as any suitable fiber material or materials can be utilized for the fibers 17 that are disposed in the material 16. For example, the polymeric material 16 can comprise a high Mooney fiber-loaded elastomeric material, such as a neoprene rubber loaded with non-metallic organic fibers that have a diameter in the approximate range of 25 to 1250 micrometers (0.001 to 0.050 of an inch), and a length in the approximate range of 25 micrometers (0.001 of an inch) to as much as one inch (25400 micrometers), and wherein the material 16 has a Mooney ML/+4 rating of approximately 40 to 50 at 99°C (210° F), and a Garlock Flow Index rating of 7 to 8 cm when forced through an orifice of 2.540 mm (0.100 of an inch) with a pressure of 14000 kPa (2,000 psi) and while at a temperature of approximately 135°C (275° F). In such example for the material 16, it is preferred that the outer polymeric material 21 comprise a gum rubber having a Mooney ML/+4 rating of approximately 80 to 100 at 100°C (212° F), and a Garlock Flow Index of approximately 30 to 40 mm when being forced through the orifice of 2.540 mm (0.100 of an inch) with a pressure of 14000 kPa (2,000 psi) while at a temperature of 135°C (275° F).

Claims: A method of making a belt construction having opposed sides (11, 12) and comprising a tensile means (13) intermediate said opposed sides, a plurality of teeth (14) defining one of said opposed sides of said belt construction and being mainly formed of a first polymeric material (16) that has reinforcing fibers (17) therein, each tooth (14) having opposed sides (18, 19) that are disposed in spaced relation to adjacent sides (19, 18) of adjacent teeth (14), said belt construction having a land area (20) between adjacent teeth ; and a backing member (15) defining the other of said opposed sides of said belt construction, said backing member (15) being substantially free of fibers therein, said material (21) of said backing member (15) having a surface (22) that joins with a surface (23) of each tooth, whereby said joining surfaces (22, 23) define an interface line (24) therebetween, said interface line (24) for each tooth (14) extending from said tensile means (13) at a point (26) inboard of one of said opposed sides (18) of the respective tooth (14) into the medial portion (27) of said respective tooth (14) and then back to said tensile means (13) at a point (28) inboard of the other (19) of said opposed sides of said respective tooth, whereby part (29) of said material (21) of said backing member (15) defines part of the medial portion (27) of each tooth, said surface (22) of said backing member (15) joining with a surface (30) of said first material (16) in each land area (20), whereby said joining surfaces (22, 30) in each land area (20) define an interface line (31) therebetween, which inferface line (31) in each land area (20) has a portion (32) thereof disposed spaced from said tensile means (13) on the side (33) thereof opposite to the side (25) thereof that faces toward said teeth (14), said tensile means (13) resting directly on the land area (20) on part thereof opposite said portion (32) of said interface line (31) ; and in that said backing member (15) is mainly formed from a second polymeric material (21), including the steps of providing a drum (41) having grooves (42), disposing said tensile means (13) about said drum, and then disposing said first polymeric material (16) about said tensile means, characterized by then disposing said second polymeric material (21) about said first polymeric material (16), whereby said second polymeric material remains substantially separate from said first polymeric material, and then subjecting said drum (41) to heat and pressure to cause said first and second materials (16, 21) to be forced toward said drum, whereby said first and second materials exude partly through said tensile means and into said grooves (42) to define said interface line (24) for each tooth (14) and to form said interface line (31) in each land area (20) in such a way that a portion (32) thereof is disposed spaced from, but parallel to said tensile means (13) on the side (33) thereof opposite to the side (25) thereof that faces toward said teeth (14). A method of making a belt construction as set forth in claim 1, characterized by forming said first polymeric material (16) to have said reinforcing fibers (17) oriented therein. A method of making a belt construction as set forth in claim 2, characterized by orienting said reinforcing fibers (17) of said first polymeric material (16) so as to be substantially oriented in a direction that extends between said opposed sides (18, 19) of each tooth (14). A method of making a belt construction as set forth in claim 1, characterized by covering said opposed sides (18, 19) of each tooth (14) with reinforcing fabric means (36). A method of making a belt construction as set forth in claim 1, characterized by forming said interface line (24) of each tooth (14) to be substantially arcuate between said points (26, 28) thereof. A method of making a belt construction as set forth in claim 1, characterized by forming said portion (32) of said interface line (31) in each land area (20) to be generally parallel to said tensile means (13). A method of making a belt construction as set forth in claim 1, characterized by forming said interface line (31) in each land area (20) to join with said interface line (24) of each tooth (14) that is adjacent thereto, by means of a joining portion (34) that extends through the spaces between adjacent cord strands of the tensile means (13). A method of making a belt construction as set forth in claim 1, characterized by disposing a fabric layer (36) about said drum (41) before said step of disposing said tensile means (13) whereby said fabric layer (36) covers said opposed sides (18, 19) of each tooth (14).

Inventors: MARSH, RICHARD L., WETZEL, ROBERT E.
Applicants: DAYCO PRODUCTS, INC.
Application year: 1984
Main classification: F16G1
IPC codes: B29D29, F16G1