Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1998-11-27
2001-02-06
Maki, Steven D. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C425S028100, C425S034200, C474S205000, C474S250000
Reexamination Certificate
active
06183582
ABSTRACT:
TECHNICAL FIELD
This invention relates to synchronous drive belts and timing belts and more specifically to a method and apparatus for manufacturing a synchronous drive belt having two or more tracks of teeth which extend from the belt surface at oppositely balanced oblique angles.
BACKGROUND ART
U.S. Pat. No. 5,209,705 to Gregg ostensibly discloses a synchronous drive belt with oblique and offset teeth.
U.S. Pat. No. 3,078,206 to Skura ostensibly discloses a method of forming belt teeth and reinforced positive drive belts.
U.S. Pat. No. 2,600,775 ostensibly discloses a method and apparatus for making and curing power transmission belts.
Finally, Japanese Patent No. 59-133,034 is also directed to a method of manufacturing a synchronous drive belt.
Synchronous drive belts generally comprise a resilient elastomer reinforced with a longitudinal tensile member made up of a plurality of cords of a high elastic modulus. The cords may be made from glass fiber, carbon fiber, steel, polyester, high tenacity rayon or preferably, polyamide.
The tooth surface of the belt may be reinforced with an abrasion resistant fabric, one example of which is nylon.
The elastomers may be any one of those known to be suitable for use in such belts, including polychloroprene, polyurethane, NBR, IIR, IR, SBR, CSM, EPDM, other thermosets, thermoplastic elastomers and other polymer alloys.
Typically, synchronous drive belts are manufactured by winding layers of fabric, unvulcanized elastomer and cord on a drum. The drum functions as an internal mold and may have a periphery consisting of axially oriented evenly pitched grooves. During vulcanization, the belt slab is molded by pressure exerted by an external diaphragm or autoclave which forces the slab radially inwardly against the drum periphery. After vulcanization, the belt sleeve is slid axially off the drum or mold. The sleeve is then slit transversely into individual belts in a separate operation.
The synchronous belts so formed normally have a single track of teeth extending from the belt at right angles to the belt circumference, the teeth having dimensions compatible with the grooves on the drum periphery. A simple grooved drum is utilized in the manufacture of such belts.
It is known in the art to provide synchronous belts having at least two transversely adjacent rows of teeth which are at oppositely balanced oblique angles to the direction of the belt. One such belt structure is disclosed in U.S. Pat. No. 5,209,705 the disclosure of which is incorporated herein by reference. The belt structure disclosed therein provides certain advantages, especially relating to noise, which offer improvements over belts having a single track of teeth which extend at right angles to the belt circumference.
A problem encountered in the art, however, is the ability to manufacture the improved belts by a method that allows the building and vulcanization of a band having more than one belt section on an internal drum mold. The presence of the two or more tracks of teeth extending at oppositely balanced oblique angles on each belt section bars the cured belt sleeve from being slid axially off the drum mold, as is done in the prior art manufacturing method described above. Heretofore there has not been a viable method of manufacture of the improved belts.
The inventive process described herein provides a method whereby a synchronous belt having two or more tracks of teeth extending at oppositely balanced oblique angles may be advantageously manufactured in a way that is simple and effective.
DISCLOSURE OF INVENTION
In accordance with the practice of the present invention, there is provided a method of manufacturing a synchronous drive belt having teeth extending from a belt surface which comprises the steps of:
assembling an internal drum mold having a first set of concentric molding rings comprising adjacent right hand and left hand rings, the right and left hand rings having teeth-forming grooves therein, the grooves on each of the right and left hand rings being separated by a pre-determined pitch;
building a multi-plied belt band around the drum mold;
curing the belt band;
segmenting the cured belt band into belt widths; and,
removing the belt widths from the mold after segmenting the belt band into widths.
In accordance with another aspect of the invention, the grooves of the right hand ring are obliquely angled relative to a longitudinal direction and the grooves of the left hand ring are oppositely angled to the grooves of the right hand ring. In the inventive method, the step of assembling the internal drum mold comprises:
positioning the right hand ring in a predetermined position relative to the left hand ring such that the grooves on the right hand ring are offset from the grooves on the left hand ring by a predetermined distance; and,
employing holding means for holding the right hand ring in the predetermined position relative to the left hand ring.
In accordance with another aspect of the invention, the step of building a multi-plied belt band around the drum mold comprises:
laying a first fabric ply against the internal drum mold;
positioning a longitudinal tensile member over the fabric ply;
layering an elastomeric material over the tensile member; and,
layering a transverse reinforcement member over the elastomeric material.
In accordance with another aspect of the invention, the step of assembling the internal drum mold further comprises:
placing a spacer ring between first and second sets of molding rings.
In accordance with another aspect of the invention, the step of segmenting the cured belt band into belt widths comprises:
mounting the drum mold assembly onto a lathe; and,
cutting the cured belt band on either side of the first molding ring set.
According to another aspect of the invention, the step of removing the belt widths from the mold after the step of segmenting the belt band into widths comprises:
sliding the right hand ring away from the belt width in a first direction; and,
sliding the left hand ring away from the belt width in a second direction.
One advantage of the present invention is the ability to effectively manufacture synchronous belts having two or more adjacent rows of obliquely angled teeth.
Another advantage of the present invention is the ability to vary the number of synchronous belts made in one curing operation.
Another advantage of the present invention is the precision with which the angled teeth of a finished belt can be produced.
A Another advantage of the present invention is the replaceability of drum sections which may be damaged or become out of desired tolerance during operation.
Another advantage of the present invention is the ability to incorporate portions of conventional belt building methods to form an improved belt structure.
Still other benefits and advantages of the invention will become apparent to those skilled in the art to which it pertains upon a reading and understanding of the following detailed specification.
REFERENCES:
patent: 2600775 (1952-06-01), Hurry et al.
patent: 2709277 (1955-05-01), Dixon et al.
patent: 2983637 (1961-05-01), Schmidt
patent: 3078205 (1963-02-01), Sauer et al.
patent: 3078206 (1963-02-01), Skura
patent: 3565984 (1971-02-01), Sauer
patent: 3784338 (1974-01-01), Previati
patent: 4311474 (1982-01-01), Standley
patent: 4504342 (1985-03-01), Marsh et al.
patent: 5209705 (1993-05-01), Gregg
patent: 5320516 (1994-06-01), Moitzfeld
patent: 5653655 (1997-08-01), Onoe et al.
patent: 5733399 (1998-03-01), Wood
patent: 3133820 (1983-03-01), None
patent: 0064576 (1982-11-01), None
patent: 1247809 (1960-10-01), None
patent: 2089305 (1971-12-01), None
patent: 2088277 (1980-12-01), None
patent: WO91/04145 (1991-04-01), None
Emerson Roger D
Emerson & Associates
Maki Steven D.
The Goodyear Tire & Rubber Company
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