Electronic overspeed switch

Claim 2

An electrical speed control system for selectively connecting an accessory to an engine having a rotating electric signal producing device and a rotating shaft, said speed control system comprising: means connected to receive a signal from said signal producing device for producing a speed signal indicative of the rotational speed of said shaft; signal level sensing means connected to receive said speed signal for determining if said speed signal is indicative of a speed below a preselected first level and if said speed signal is indicative of a speed above a preselected second level, and for producing an energization signal whenever said speed signal is below said first preselected threshold level, for interrupting said energizing signal when said speed signal is above said second level for maintaining said interruption of said energization signal until said speed signal falls below said first preselected level and for reestablishing said energizing signal when said speed signal again falls below said first preselected level; and switch means connected to said accessory means, and a source of electrical power, said energization signal actuating said switch whenever said energization signal is present.

Claim 3

The system of claim 1, wherein said means for producing a speed signal includes a frequency to voltage converter electrically connected to the output of said electrical signal producing device.

Claim 4

The system of claim 1 further comprising means for manually adjusting said first preselected level.

Claim 5

The system of claim 1 further comprising means for manually adjusting said second preselected level.

Claim 6

The system of claim 1, wherein said signal level sensing means comprises: first comparator means connected to said speed signal for producing an output signal indicating when said speed signal is below said first preselected level; second comparator means connected to said speed signal for producing an output signal indicating when said speed signal is below said second preselected level; and latch means connected to said first and second comparator output signals for producing said energization signal when said first comparator means output signal is present, for interrupting said energization signal when said second comparator means output signal is absent, and for maintaining said interruption until both first and second comparator means output signals are present simultaneously.

Claim 7

An electronic speed control system for use in selectively controlling the driving of an accessory by the rotating shaft of an engine of the type employing an alternator; said system comprising: convertor means electrically connected to said alternator for producing a rotational speed signal which is a function of the rotational speed of said rotating shaft; first level detecting means connected to receive said rotational speed signal for producing an output signal indicating that the speed is below a first preselected threshold level; latch means connected to receive said first and second level detecting means output signals for producing an output signal only if said speed is below said first preselected threshold level, has exceeded said first preselected threshold level and is below said second preselected threshold level and having exceeded said second level, falls below said first preselected threshold level; and switch means connected to receive said output signal of said latch means and connected to said accessory and an electric power source for actuating said accessory only upon the occurrence of said output signal from said latch means.

Claim 8

An electronic speed control system for use in selectively controlling the driving of an accessory by the rotating shaft of an engine of the type employing an alternator; said system comprising: convertor means electrically connected to said alternator for producing a rotational speed signal which is a function of the rotational speed of said rotating shaft; first level detecting means connected to receive said rotational speed signal for producing an output signal indicating that the speed is below a first preselected threshold level; latch means connected to receive said first and second level detecting means output signals for producing an output signal only if said speed is below said first preselected threshold level, has exceeded said first preselected threshold level and is below said second preselected threshold level and having exceeded said second level, falls below said first preselected threshold level; and switch means connected to receive said output signal of said latch means and connected to said accessory and an electric power source for actuating said accessory only upon the occurrence of said output signal from said latch means.

Claim 9

The system of claim 6, further comprising means for manually adjusting said first preselected threshold level.

Claim 10

The system of claim 6, further comprising means for manually adjusting said second preselected threshold level.

Claim 11

The system of claim 6, wherein said first level detecting means comprises a comparator having one input connected to said rotational speed signal and the other input connected to the wiper arm of a potentiometer for setting said first preselected threshold level.

Claim 12

The system of claim 6, wherein said second level detecting means comprises a comparator having one input connected to said rotational speed signal and the other input connected to the wiper arm of a potentiometer for setting said second preselected threshold level.

Claim 13

An electronic speed control system for use in selectively controlling the driving of an accessory by a rotating shaft, said system comprising: means connected to said rotating shaft for producing a speed signal which is a function of the rotational speed of said rotating shaft; first level detecting means connected to receive said speed signal for producing an output signal indicating that the speed is below a first preselected threshold level; second level detecting means connected to receive said speed signal for producing an output signal indicating that the speed is above a second predetermined threshold level; latch means connected to receive said first and second level detecting means output signals for producing an output signal only if said speed is below said first preselected threshold level, has exceeded said first preselected threshold level and is below said second preselected threshold level and having exceeded said second level, falls below said first preselected threshold level; and switch means connected to receive said output signal of said latch means and connected to said accessory and an electric power source for actuating said accessory only upon the occurrence of said output signal from said latch means.

Claim 14

An electronic speed control system for use in selectively controlling the driving of an accessory by a rotating shaft, said system comprising: means connected to said rotating shaft for producing a speed signal which is a function of the rotational speed of said rotating shaft; first level detecting means connected to receive said speed signal for producing an output signal indicating that the speed is below a first preselected threshold level; second level detecting means connected to receive said speed signal for producing an output signal indicating that the speed is above a second predetermined threshold level; latch means connected to receive said first and second level detecting means output signals for producing an output signal only if said speed is below said first preselected threshold level, has exceeded said first preselected threshold level and is below said second preselected threshold level and having exceeded said second level, falls below said first preselected threshold level; and switch means connected to receive said output signal of said latch means and connected to said accessory and an electric power source for actuating said accessory only upon the occurrence of said output signal from said latch means.

Claim 15

In combination with a system for driving an accessory from an engine wherein the accessory cannot be safely connected to the engine above a first engine speed and once connected, cannot be safely operated above a second engine speed, a speed control system having a first means for selectively connecting and disconnecting an accessory to and from the engine, the engine having a rotating shaft and a signal generating device for producing a speed signal indicative of the speed of rotation of the rotating shaft; said speed control system comprising: second means establishing a first signal level indicative of said first engine speed, third means establishing a second signal level indicative of said second engine speed, said first means permitting connection of an accessory to the rotating shaft only when said speed signal is less than said first signal level and causing an accessory to be disconnected from said rotating shaft when said speed signal exceeds said second signal level, said first means permitting reconnection of an accessory to the rotating shaft after an accessory has been disconnected from the rotating shaft only when said speed signal is again less than said first signal level.

Claim 16

In combination with a system for driving an accessory from an engine wherein the accessory cannot be safely connected to the engine above a first engine speed and once connected, cannot be safely operated above a second engine speed, a speed control system having a first means for selectively connecting and disconnecting an accessory to and from the engine, the engine having a rotating shaft and a signal generating device for producing a speed signal indicative of the speed of rotation of the rotating shaft; said speed control system comprising: second means establishing a first signal level indicative of said first engine speed, third means establishing a second signal level indicative of said second engine speed, said first means permitting connection of an accessory to the rotating shaft only when said speed signal is less than said first signal level and causing an accessory to be disconnected from said rotating shaft when said speed signal exceeds said second signal level, said first means permitting reconnection of an accessory to the rotating shaft after an accessory has been disconnected from the rotating shaft only when said speed signal is again less than said first signal level.

Claim 17

In combination with a system for driving an accessory from an engine wherein the accessory cannot be safely connected to the engine above a first engine speed and once connected, cannot be safely operated above a second engine speed, a speed control system having a means for selectively connecting the accessory to the engine, the engine having a rotating shaft and a signal generating device for producing a speed signal indicative of the speed of rotation of the rotating shaft; said speed control system comprising: first means connected to receive said speed signal from said signal generating device, second means establishing a first signal level indicative of said first engine speed, third means establishing a second signal level indicative of said second engine speed, fourth means permitting connection of an accessory to the rotating shaft only when said speed signal is less than said first signal level, and fifth means causing an accessory to be disconnected from said rotating shaft when said speed signal exceeds said second signal level, said fourth means permitting reconnection of an accessory to the rotating shaft after an accessory has been disconnected by said fifth means only when said speed signal signal is again less than said first signal level.

Claim 18

In combination with a system for driving an accessory from an engine wherein the accessory cannot be safely connected to the engine above a first engine speed and once connected, cannot be safely operated above a second engine speed, a speed control system having a means for selectively connecting the accessory to the engine, the engine having a rotating shaft and a signal generating device for producing a speed signal indicative of the speed of rotation of the rotating shaft; said speed control system comprising: first means connected to receive said speed signal from said signal generating device, second means establishing a first signal level indicative of said first engine speed, third means establishing a second signal level indicative of said second engine speed, fourth means permitting connection of an accessory to the rotating shaft only when said speed signal is less than said first signal level, and fifth means causing an accessory to be disconnected from said rotating shaft when said speed signal exceeds said second signal level, said fourth means permitting reconnection of an accessory to the rotating shaft after an accessory has been disconnected by said fifth means only when said speed signal signal is again less than said first signal level.