Machinery's Handbook, 31st Edition
Non-metallic Gears
2327
Preferred Pitches for Non-Metallic Gears Applicable both to rawhide and the phenolic laminated types of materials Diametral Pitch for Given Horsepower and Pitch Line Velocities
Pitch Line Velocity up to 1000 Feet per Minute
Pitch Line Velocity from 1000 to 2000 Feet per Minute
Pitch Line Velocity over 2000 Feet per Minute
Horsepower Transmitted
8-10
10-12 8-10
12-16 10-12 8-10
4 -1
1 ∕
1-2 2-3
7-8 6-7 5-6 4-5 3-4
7-8 6-7 5-6 4-5 3-4
7-8 6-7 5-6 4-5 3-4
3-7 1 ∕
2
7 1 ∕
2 -10
10-15 15-25 25-60 60-100 100-150
2 -3
2 1 ∕
2
2 -3
2-2 1 ∕
1 ∕
2
4 -2
2-2
2
2 -3
1 3 ∕
1 ∕
1 ∕
2
2 -1
1
4 -2
2-2
1 1 ∕
3 ∕
3 ∕
1 ∕
4
2
Torque in Pounds-Feet for Given Diametral Pitch
Torque in Pounds-feet Minimum Maximum
Torque in Pounds-feet Minimum Maximum
Diametral Pitch
Diametral Pitch
16 12 10
1 2 4 8
2 4 8
4 3
50 100 200 450 900
100 200 450 900
2 1 ∕
2
8 6 5
15 30 50
2
15 30
1800 3500
1 1 ∕
2
1
1800
63,000 rpm
hp psi
9,550 rpm
kw N-m
S = When the design is such that the keyway stresses exceed 3000 psi (20.68 MPa), metal reinforcing end plates may be used. Such end plates should not extend beyond the root diameter of the teeth. The distance from the outer edge of the retaining bolt to the root diameter of the teeth shall not be less than a full tooth depth. The use of drive keys should be avoided, but if required, metal end plates should be used on the pinion to take the wedg ing action of the key. For phenolic laminated pinions, the face of the mating gear should be the same or slightly greater than the pinion face. r A S r A # # # = Invention of Gear Teeth.— The invention of gear teeth represents a gradual evolution from gearing of primitive form. The earliest evidence we have of an investigation of the prob- lem of uniform motion from toothed gearing and the successful solution of that problem dates from the time of Olaf Roemer, the celebrated Danish astronomer, who, in the year 1674, proposed the epicycloidal form to obtain uniform motion. Evidently Robert Willis, professor at the University of Cambridge, was the first to make a practical application of the epicycloidal curve so as to provide for an interchangeable series of gears. Willis gives credit to Charles Étienne Louis Camus for conceiving the idea of interchangeable gears, but claims for himself its first application. The involute tooth was suggested as a theory by early scientists and mathematicians, but it remained for Willis to present it in a practical form. Perhaps the earliest conception of the application of this form of teeth to gears was by Philippe de Lahire, a Frenchman, who considered it, in theory, equally suitable with the # # #
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