Patent US3581853A successfully refreshed from Google Patents.
US3581853A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Two-speed motor-bike drive
Assignee: Hoffco Inc
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Filing: 1969-04-21
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Granted: 1971-06-01
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Expires: 1989-04-21
Abstract
Abstract A two-speed chain transmission for minibikes, as original equipment or as a conversion kit. High- and low-speed sprockets on a jackshaft are chain driven at different speeds by high and low drive sprockets carried by a centrifugal clutch on the engine shaft. The jackshaft is chain connected to the rear wheel of the bike. The low speed driven sprocket is mounted on the jackshaft by an overrunning clutch which permits the jackshaft to overrun the low drive when it is driven by the high drive. The high-speed sprocket is mounted on the jackshaft by a clutch which is disengageable to let the low-speed drive takeover. A brake acts on the jackshaft on the driven side of the clutches.
Inventors
- 👤 Stephen J Hoff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:24
CPC Classifications
B; B62; B62M; B62M7/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
218 words
A two-speed drive for a motorbike having an engine shaft, a jackshaft and a drive wheel, adapted to be positively controlled by the operator of the motorbike, comprising high-speed and low-speed drive sprockets mounted for rotation by said engine shaft, high-speed and low-speed driven sprockets or transmitting drive to the drive wheel, mounted on said jackshaft and connected respectively to said drive sprockets to provide high-speed and low-speed drive trains, said low-speed driven sprocket being connected to the jackshaft by an overrunning clutch arranged to overrun when the highspeed drive train is engaged, said high-speed driven sprocket being connected to the jackshaft by a disengageable high-speed clutch, and operating means arranged for positive control by the operator to disengage said high-speed clutch and thereby cause the low-speed drive train to become operative, said disengageable clutch comprising a driving clutch member rotatably mounted on the jackshaft with the high-speed driven sprocket, a driven clutch member fixed to the jackshaft, said driving and driven clutch members having aligned cylindrical clutch surfaces, and a coil spring engaged with said clutch surfaces and wound in a direction to clutch the same together for forward drive transmission, and said operating means comprising blocking means to block rotation of the leading end of said clutch spring to disengage the same from both clutch surfaces.
Claim 2
Dependent Claim
218 words
A two-speed drive for a motorbike having an engine shaft, a jackshaft and a drive wheel, adapted to be positively controlled by the operator of the motorbike, comprising high-speed and low-speed drive sprockets mounted for rotation by said engine shaft, high-speed and low-speed driven sprockets or transmitting drive to the drive wheel, mounted on said jackshaft and connected respectively to said drive sprockets to provide high-speed and low-speed drive trains, said low-speed driven sprocket being connected to the jackshaft by an overrunning clutch arranged to overrun when the highspeed drive train is engaged, said high-speed driven sprocket being connected to the jackshaft by a disengageable high-speed clutch, and operating means arranged for positive control by the operator to disengage said high-speed clutch and thereby cause the low-speed drive train to become operative, said disengageable clutch comprising a driving clutch member rotatably mounted on the jackshaft with the high-speed driven sprocket, a driven clutch member fixed to the jackshaft, said driving and driven clutch members having aligned cylindrical clutch surfaces, and a coil spring engaged with said clutch surfaces and wound in a direction to clutch the same together for forward drive transmission, and said operating means comprising blocking means to block rotation of the leading end of said clutch spring to disengage the same from both clutch surfaces.
Claim 3
Dependent Claim
48 words
A two-speed drive according to claim 1 with the addition of a centrifugal clutch having a shoe assembly mounted on the engine shaft and a clutch drum rotatably mounted coaxially with and engageable by the shoe assembly, the drive sprockets being mounted for rotation with the clutch drum.
Claim 4
Dependent Claim
51 words
A two-speed drive according to claim 1 with the addition of means to connect the jackshaft in positive drive relation to the drive wheel, a brake rotor on the jackshaft and means for braking said rotor to apply braking effort in the drive train between said clutches and the drive wheel.
Claim 5
Dependent Claim
165 words
A kit for providing an operator-controlled two-speed drive for a motorbike having a frame, an engine support, an engine having a shaft, and a drive wheel, comprising an engine platform adapted to be mounted on the engine support of the motorbike and to receive the engine thereon, a high-speed drive sprocket and a low-speed drive sprocket adapted to be mounted on and driven by the engine shaft, jackshaft bearings fixed to the platform in position to mount a jackshaft on an axis between the engine and the drive wheel, a jackshaft mounted in said bearings, a low-speed driven sprocket mounted on said jackshaft and operatively connected thereto by an overrunning clutch adapted to permit the jackshaft to overrun said driven sprocket in the forward drive direction of rotation thereof, a high-speed driven sprocket mounted on said jackshaft and operatively connected thereto by a disengageable clutch, and operating means adapted for positive control by the operator for actuating said disengageable clutch between engaged and disengaged conditions.
Claim 6
Dependent Claim
165 words
A kit for providing an operator-controlled two-speed drive for a motorbike having a frame, an engine support, an engine having a shaft, and a drive wheel, comprising an engine platform adapted to be mounted on the engine support of the motorbike and to receive the engine thereon, a high-speed drive sprocket and a low-speed drive sprocket adapted to be mounted on and driven by the engine shaft, jackshaft bearings fixed to the platform in position to mount a jackshaft on an axis between the engine and the drive wheel, a jackshaft mounted in said bearings, a low-speed driven sprocket mounted on said jackshaft and operatively connected thereto by an overrunning clutch adapted to permit the jackshaft to overrun said driven sprocket in the forward drive direction of rotation thereof, a high-speed driven sprocket mounted on said jackshaft and operatively connected thereto by a disengageable clutch, and operating means adapted for positive control by the operator for actuating said disengageable clutch between engaged and disengaged conditions.
Claim 7
Dependent Claim
70 words
A two-speed drive kit according to claim 4, further comprising a mounting bracket including said engine platform adapted to be mounted on the engine support of the motorbike and to receive the engine thereon, and a bearing tube transversely fixed to the bracket in position to lie between an engine received on the platform and the drive wheel of the bike, said jackshaft bearings being mounted in said bearing tube.
Claim 8
Dependent Claim
52 words
A two-speed drive kit according to claim 4, further comprising a brake support bar fixed to said bracket and projecting beyond said bearing tube in offset relation to its axis, a brake rotor on the jackshaft, and a brake mean carried by said bar for applying braking effort to the brake rotor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |