Abstract Electric circuit for preventing the burning of an electric motor energized by an electric source through the electric circuit. The electric circuit has a memory circuit actuated by a setting input pulse and reset by a resetting input pulse, a timing circuit connected to said memory circuit so as to be actuated thereby when the same is actuated while the timing circuit is rendered to be inoperative when the memory circuit is reset or a resetting input pulse is applied to the timing circuit, a relay connected to the timing circuit so as to be energized when the same is actuated, and a switch operatively coupled with the relay so as to energize the motor when the relay is energized while the motor is deenergized by the switch when the relay is deenergized, thereby permitting the motor to continue to be driven upon application of the setting input pulse to the memory circuit until the resetting input pulse is applied thereto. The timing circuit comprises a monostable multivibrator having a predetermined holding time which is selected to be suitable for preventing the burning of the motor under the overloaded condition. Thus, the motor is automatically deenergized after the energization thereof by virtue of the holding time before the resetting input pulse is applied to the memory circuit under the overloaded condition of the motor, while the reenergization of the motor by applying a further setting input pulse to the memory circuit is prevented until a resetting input pulse is applied to the memory circuit prior to the application of the further setting input pulse thereto.
In an electric circuit for preventing the burning of an electric motor energized by an electric source through said electric circuit, said electric circuit having a memory circuit actuated by a setting input pulse applied thereto and reset by a resetting input pulse applied thereto, a timing circuit connected to said memory circuit so as to be actuated thereby when the same is actuated while said timing circuit is rendered to be inoperative when said memory circuit is reset or resetting input pulse is applied to said timing circuit, a relay connected to said timing circuit so as to be energized thereby when the same is actuated, and a switch operatively coupled with said relay so as to energize said motor when said relay is energized while said motor is deenergized by said switch when said relay is deenergized, thereby permitting said motor to continue to be driven upon application of said setting input pulse to said memory circuit until said resetting input pulse is applied thereto, the improvement wherein said timing circuit comprises a monostable multivibrator having a predetermined holding time to automatically reset the same after expiration of said holding time, said holding time being selected to be suitable for preventing the burning of said motor under the overloaded condition thereof, thereby permitting said motor to be automatically deenergized after the energization thereof by virtue of said holding time even bEfore said resetting input pulse is applied to said memory circuit under the overloaded condition of said motor, while the reenergization of said motor by applying a further setting input pulse to said memory circuit is prevented until a resetting input pulse is applied to said memory circuit prior to the application of said further input pulse thereto.
Claim 2
Dependent Claim
290 words
In an electric circuit for preventing the burning of an electric motor energized by an electric source through said electric circuit, said electric circuit having a memory circuit actuated by a setting input pulse applied thereto and reset by a resetting input pulse applied thereto, a timing circuit connected to said memory circuit so as to be actuated thereby when the same is actuated while said timing circuit is rendered to be inoperative when said memory circuit is reset or resetting input pulse is applied to said timing circuit, a relay connected to said timing circuit so as to be energized thereby when the same is actuated, and a switch operatively coupled with said relay so as to energize said motor when said relay is energized while said motor is deenergized by said switch when said relay is deenergized, thereby permitting said motor to continue to be driven upon application of said setting input pulse to said memory circuit until said resetting input pulse is applied thereto, the improvement wherein said timing circuit comprises a monostable multivibrator having a predetermined holding time to automatically reset the same after expiration of said holding time, said holding time being selected to be suitable for preventing the burning of said motor under the overloaded condition thereof, thereby permitting said motor to be automatically deenergized after the energization thereof by virtue of said holding time even bEfore said resetting input pulse is applied to said memory circuit under the overloaded condition of said motor, while the reenergization of said motor by applying a further setting input pulse to said memory circuit is prevented until a resetting input pulse is applied to said memory circuit prior to the application of said further input pulse thereto.
Claim 3
Dependent Claim
51 words
Electric circuit according to claim 1, wherein said resetting input pulse is generated by the medium of a cam operatively coupled with said motor and capable of actuating a switch in cooperation therewith so that said motor is stopped automatically after the predetermined rotation there of under the normally loaded condition.
Claim 4
Dependent Claim
41 words
Electric circuit according to claim 1, wherein said switch is so connected to said motor that both the terminals of said motor are short circuited by said switch when said relay is deenergized thereby applying electromagnetic braking force to said motor.
Claim 5
Dependent Claim
70 words
Electric circuit according to claim 2 which is incorporated in an automatic film takeup device of a photographic camera, wherein said cam is fixedly secured to a shaft of film takeup sprockets driven by said motor by one revolution at a time through a gear train for taking up the film by one frame and said setting input pulse is generated by the medium of synchronizing contacts of said camera.