Patent US4036071A successfully refreshed from Google Patents.
US4036071A
Expired / Lapsed
US
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Sprocket and method for producing same
Assignee: HOLLIS AND Co
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Filing: 1976-04-02
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Granted: 1977-07-19
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Expires: 1996-04-02
Abstract
Abstract A sprocket designed to drive chains in power transmission systems, which is characterized by a tooth profile having clearance, loading, and topping curves tailored to a selected chain barrel diameter and chain pitch, a selected pressure angle compatible with minimum stress on each engaged tooth of the sprocket, and a continuously curving tooth profile also contributing to the minimizing of stresses.
Inventors
- 👤 Oliver R. McKnight
- 👤 William M. Seaman, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:55
CPC Classifications
F; F16; F16H; F16H55/00; F16H55/02; F16H55/30; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49453; Y10T74/00; Y10T74/19; Y10T74/19949; Y10T74/19963; Y10T74/19972
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
263 words
A method of producing a template profile for a sprocket comprising: a. selecting a sprocket face width, number of sprocket teeth, chain pitch and chain barrel diameter for a selected sprocket application; b. laying out the sprocket center; c. calculating a pitch diameter by dividing said chain pitch by the trigonometric function: sin (180° ÷ number of sprocket teeth selected); d. inscribing a pitch circle about said sprocket center using said pitch diameter; e. forming a regular polygon within said pitch circle, said polygon having chordal lines corresponding to the length of said chain pitch; f. laying out additional lines corresponding in length to said pitch diameter and running through said sprocket center connecting pitch points formed by coincidence of said chordal lines with the intersections of said chordal lines of said regular polygon; g. laying out first reference lines through said pitch points perpendicular to said additional lines connecting said pitch points and tangent to said pitch circle at said pitch points; h. calculation of a loading curve angle by adding: 40° + (60° ÷ said number of sprocket teeth selected); i. laying out second reference lines through said pitch points along said first reference lines and rotated from said first reference lines through said loading curve angle at said pitch points; j. establishing loading curve center point distances from said pitch points along said second reference lines by multiplying 0.9 × (said chain barrel diameter + 0.18); k. laying out loading curve center points by measuring said loading curve center point distance along said second reference lines from said pitch points;
Claim 2
Independent Claim
263 words
A method of producing a template profile for a sprocket comprising: a. selecting a sprocket face width, number of sprocket teeth, chain pitch and chain barrel diameter for a selected sprocket application; b. laying out the sprocket center; c. calculating a pitch diameter by dividing said chain pitch by the trigonometric function: sin (180° ÷ number of sprocket teeth selected); d. inscribing a pitch circle about said sprocket center using said pitch diameter; e. forming a regular polygon within said pitch circle, said polygon having chordal lines corresponding to the length of said chain pitch; f. laying out additional lines corresponding in length to said pitch diameter and running through said sprocket center connecting pitch points formed by coincidence of said chordal lines with the intersections of said chordal lines of said regular polygon; g. laying out first reference lines through said pitch points perpendicular to said additional lines connecting said pitch points and tangent to said pitch circle at said pitch points; h. calculation of a loading curve angle by adding: 40° + (60° ÷ said number of sprocket teeth selected); i. laying out second reference lines through said pitch points along said first reference lines and rotated from said first reference lines through said loading curve angle at said pitch points; j. establishing loading curve center point distances from said pitch points along said second reference lines by multiplying 0.9 × (said chain barrel diameter + 0.18); k. laying out loading curve center points by measuring said loading curve center point distance along said second reference lines from said pitch points;
Claim 3
Dependent Claim
152 words
calculating clearance curve radii by adding 0.18 to said chain barrel diameter and dividing by 2; m. laying out clearance curves from said clearance curve radii by inscribing an arc from each of said pitch points through said additional lines corresponding to said pitch diameter to form the fillets of said template; n. laying out loading curves by inscribing an arc from each of said loading curve center points, continuing said clearance curves to form the tooth shoulders of said template; o. calculating topping curve center point distances by the formula: 1.2 × (2 × said clearance curve radius); p. locating topping curve center points by laying off said topping curve center point distances along said chordal lines from said pitch points; and q. laying out topping curves from said topping curve center points by extending said loading curves on each of said shoulders of said template until said topping curves meet.
Claim 4
Dependent Claim
152 words
calculating clearance curve radii by adding 0.18 to said chain barrel diameter and dividing by 2; m. laying out clearance curves from said clearance curve radii by inscribing an arc from each of said pitch points through said additional lines corresponding to said pitch diameter to form the fillets of said template; n. laying out loading curves by inscribing an arc from each of said loading curve center points, continuing said clearance curves to form the tooth shoulders of said template; o. calculating topping curve center point distances by the formula: 1.2 × (2 × said clearance curve radius); p. locating topping curve center points by laying off said topping curve center point distances along said chordal lines from said pitch points; and q. laying out topping curves from said topping curve center points by extending said loading curves on each of said shoulders of said template until said topping curves meet.
Claim 5
Dependent Claim
13 words
The method of claim 1 wherein said profile is drawn on template material.
Claim 6
Dependent Claim
19 words
The method of claim 1 wherein said profile is drawn on a selected material and transferred to template material.
Claim 7
Dependent Claim
105 words
A sprocket tooth profile in a sprocket for use in power transmission systems comprising: a. a plurality of clearance curves forming the fillet of each pair of adjacent teeth in said tooth profile, said clearance curves being a function of a selected chain barrel diameter and chain pitch; b. a plurality of loading curves forming the shoulders of said tooth profile, said loading curves being a continuation of said clearance curves; and c. a plurality of topping curves forming the top of the teeth in said tooth profile, said topping curves being a function of said clearance curves and a continuation of said loading curves.
Claim 8
Dependent Claim
105 words
A sprocket tooth profile in a sprocket for use in power transmission systems comprising: a. a plurality of clearance curves forming the fillet of each pair of adjacent teeth in said tooth profile, said clearance curves being a function of a selected chain barrel diameter and chain pitch; b. a plurality of loading curves forming the shoulders of said tooth profile, said loading curves being a continuation of said clearance curves; and c. a plurality of topping curves forming the top of the teeth in said tooth profile, said topping curves being a function of said clearance curves and a continuation of said loading curves.
Claim 9
Dependent Claim
170 words
The sprocket of claim 4 wherein: a. said clearance curves are created by establishing clearance curve radii extending from each one of a plurality of chain pitch points a distance equal to a selected chain barrel diameter plus 0.18 divided by 2, and striking clearance curve arcs from said pitch points to form said fillet for each pair of said teeth; b. said loading curves are created by locating loading curve radii from established loading curve center points by multiplying said clearance curve radii by 1.8; and striking loading curve arcs from said loading curve center points extending said clearance curve arcs to form said shoulders of said tooth profile; and c. said topping curves are created by locating topping curve radii from established topping curve center points by multiplying 2.4 times said clearance curve radius and striking topping curve arcs from said topping curve center points extending said loading curve arcs to join said clearance curve arcs at the top of each of said teeth in said tooth profile.
References Cited (Backward Citations)
US3448629A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-18 | 1981-01-17 | 1981-07-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-18 | 1985-01-17 | 1985-07-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-18 | 1989-01-17 | 1989-07-19 | $7700.00 | Window Closed / Lapsed |