Electric driving device

• US 4,279,490 A
• Filed: 10/09/1979
• Issued: 07/21/1981
• Est. Priority Date: 10/11/1978
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Fukahori, Hidehiko, Iwashita, Tomonori, Mashimo, Yukio
• Primary Examiner(s): Hix, L. T.
• Assistant Examiner(s): Brady, W. J.
• Application Number:
  US06/082,461
• Time in Patent Office: 651 Days
• Field of Search: 354/170, 354/171, 354/173, 354/212, 354/214, 352/121, 352/137, 352/169, 352/124, 318/282, 318/284, 318/291, 318/293, 318/261, 242/71, 242/71.4, 242/71.5, 242/71.6
• US Class Current: 396/406
• CPC Class Codes: G03B 17/425 motor drive cameras
• CPC Class Codes: H02P 7/03 for controlling the direction of rotation of DC motors

Abstract

In the disclosed device, forward and reverse rotation of a motor is used to wind and rewind a camera. A first semi-conductor switching element becomes conductive during winding and a second semi-conductor switching element becomes conductive during rewinding, the switching elements being connected in series across a power source. A selector switch has its fixed terminals connected to opposite poles of the power source. The motor is connected between the armature of the selector switch and the point between the switching elements. Driving circuits operate the switches so that the motor is driven in one direction when the selector switch is in one position and the reverse direction when the selector switch is in the other position and arranged to brake the motor after rewinding has stopped.

Claims

1. An electric driving device for performing winding and rewinding operations in a camera, which comprises:

a first semi-conductor switching element which becomes conductive at the time of a winding operation;

a second semi-conductor switching element which becomes conductive at the time of a rewinding operation;

said first and second switching elements being connected to form a series circuit to be connected between both poles of a power source;

a changeover switch having two fixed terminals to be connected to respective poles of the power source;

a motor with one end connected to a central point of the series circuit with another end connected to a movable terminal of the changeover switch;

first and a second motor driving circuits formed by the changeover switch and the first and second switching elements;

said first driving circuit effecting normal rotation of the motor to perform the winding operation;

said second driving circuit braking the motor at the time of stoppage of the winding operation, and effecting reverse rotation of the motor to perform the rewinding operation; and

said first driving circuit being arranged for braking the motor at the time of stoppage of the rewinding operation.

2. An electric driving device according to claim 1, wherein the second driving circuit is actuated by a constant voltage power source when the device is changed over to the rewinding operation by the cooperation of the changeover switch and the semi-conductor switching elements.