Drive unit for a carrier
OwnerThomas E. Lenkman, David C. Masseyinventors
Life of this patent
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Abstract
A drive unit for a carrier that includes a chassis with a drive wheel that is pivotable with an air spring in and out of contact with a surface over which the carrier is propelled. The air spring is in a pneumatic system including an air compressor which is connected to a processor in an electrical system. The compressor is programmed to provide a fair safe mode for the drive wheel, a runtime control for the air compressor and a battery voltage sensing circuit to shut down the electrical system during periods of inactivity.
Claims10
A drive unit for propelling a carrier across a supporting surface, said carrier having a chassis on casters, said drive unit comprising
- a drive wheel connected to an electric motor for rotating the wheel,
- said drive wheel mounted for rotation on a pivot arm attached to the chassis,
- said pivot arm resiliently biased by an extension spring such that the drive wheel is out of contact with the supporting surface,
- an air spring for counterbalancing the extension spring and biasing the drive wheel into contact with the supporting surface,
- said air spring connected to an air compressor in a pneumatic system,
- said air compressor in an electrical system with a battery power source and a processor,
- said processor having a logic board with a compressor timer programmed with a compressor timer to provide runtime control of the compressor, said compressor timer keeping track of period of time the compressor has run in a duty cycle and the period of time that the compressor has been off between duty cycles.
A drive unit for propelling a carrier across a supporting surface, said carrier having a chassis on casters, said drive unit comprising
- a drive wheel connected to an electric motor for rotating the wheel,
- said drive wheel mounted for rotation on a pivot arm attached to the chassis,
- said pivot arm resiliently biased by an extension spring such that the drive wheel is out of contact with the supporting surface,
- an air spring for counterbalancing the extension spring and biasing the drive wheel into contact with the supporting surface,
- said air spring connected to an air compressor in a pneumatic system,
- said air compressor in an electrical system with the electric motor for the drive wheel, a battery power source and a processor,
- said processor including a logic board with a compressor timer programmed to provide run time control of the compressor and programmed with a motor timer to open the electrical system shutting down the unit when the electric motor for the drive wheel has not operated for a predetermined period of time.
A carrier with a chassis on casters and a pair of mirror image drive units for propelling the carrier across a supporting surface, each of said drive units comprising:
- a drive wheel connected to an electric motor for rotating the wheel,
- said drive wheel mounted for rotation on a pivot arm attached to the chassis,
- said pivot arm resiliently biased by an extension spring such that the drive wheel is out of contact with the supporting surface,
- an air spring for counterbalancing the extension spring and biasing the drive wheel into contact with the supporting surface,
- said air spring connected to an air compressor in a pneumatic system including a normally closed air relief valve under control of a processor,
- said processor in a battery powered electrical system with an on/off switch, said processor having a logic board programmed with a compressor timer to provide runtime control of the compressor and to send a signal opening the normally closed air relief valve when the switch is moved from on to off position, said compressor timer keeping track of period of time the compressor has run in a duty cycle and the period of time that the compressor has been off between duty cycles,
- said processor further programmed to open the electrical system shutting down the unit when the electric motors for the drive wheel have not operated for a predetermined period of time.
Dependencies are inferred from the claim text.