Motor driven camera

• US 4,367,937 A
• Filed: 10/03/1979
• Issued: 01/11/1983
• Est. Priority Date: 03/24/1977
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Mashimo, Yukio, Iwashita, Tomonori
• Primary Examiner(s): Hartary, Joseph W.
• Assistant Examiner(s): Perkey, William B.
• Application Number:
  US06/081,334
• Time in Patent Office: 1,196 Days
• Field of Search: 354/171, 354/173, 354/238, 354/266-268, 354/60 R
• US Class Current: 396/303
• CPC Class Codes: G03B 17/425 motor drive cameras

Abstract

A co-ordination control system for a camera and a motor drive unit with separate electrical power sources one of which has a higher voltage than the other. The system is provided with an interface circuit including two switching elements arranged to cooperate with a common release button and connected between the circuitries of the camera and the unit so that the higher voltage of the source in the unit is prevented from being applied to the circuitry of the camera. For remotely controlled photographic purposes, the system is further provided with a control circuit for actuating these two switching elements in time-displaced relation to each other.

Claims

1. A camera system comprising:

(A) a camera including;

(a) first power source means for supplying a voltage,

(b) an exposure control circuit connected to the first power source means,

(c) first switch means connected to the exposure control circuit for switching between a first position for actuating the exposure control circuit and a second position for disabling the exposure control circuit, a connecting point between the first switch means and the exposure control circuit for forming a potential,

(B) an electric drive device including;

(d) second power source means having a voltage higher than that of the first power source means,

(e) an electric drive control circuit connected to the second power source means,

(f) voltage generating means connected to the second power source means,

(g) resistive means connected between the second power source means and the voltage generating means,

said resistive means forming a contact point for setting at the contact point a potential between the voltage generating means lower than that at the first power source means,

(h) a transistor having a base connected between the voltage generating means and the resistive means and having an emitter for producing an emitter current corresponding to the base voltage,

said transistor having an emitter connected to the connecting point between the first switch means and the first control circuit, said transistor having a collector connected to the driving control circuit,

said transistor being set to conduct when the first switch means in in the first position and set to be inverted when the first switch means is in the second position.

2. A camera system according to claim 1, wherein the electric drive device is removably attached to the camera, and the electric drive device and the camera have respective connection terminals for transmitting the output of the transistor.

3. A camera system according to claim 2, wherein the drive device further comprises second switch means connected parallel to the first switch means.

4. A camera system according to claim 3, wherein the electric drive device further comprises:

a switching element connected parallel to said second switch means,

signal generating means for controlling the switching element.

5. A camera system according to claim 4, wherein the signal generating means has an input terminal for receiving an external signal and for generating a signal to actuate the switching element when the external signal is applied to the terminal.

6. A camera with an electric drive device comprising:

first power source means for producing a voltage;

an exposure control circuit connected to the first power source means;

first switch means for switching between a closed position and an open position, said first switch means supplying power from the first power source means to the exposure control circuit when said first switch means is closed and inhibiting power when said first switch means is opened;

second switch means for switching the exposure control circuit off when it is opened and switching the exposure control circuit on when it is closed;

second power source means for supplying a higher voltage than the first power source means;

an electric driving control circuit connected to the second power source means;

accumulating means for charging from the first power source means when the first switch means is opened and for discharging when the first switch means is closed;

a first transistor for being turned on by the discharge of the accumulating means;

a second transistor for being turned on by the turning-on of the first transistor, said second transistor forming a self-holding circuit together with the first transistor, and

a third transistor having a base for receiving the output of the second transistor, having an emitter connected to the second switch means, having a collector connected to the electric driving control circuit, for turning on when the second switch means is closed and for turning off when the second switch means is opened, so as to control the operation of the electric drive control circuit.

7. A camera according to claim 6, further comprising third switch means connected parallel to the first switch means, and fourth switch means connected parallel to the second switch means.

8. A camera according to claim 7, further comprising a first switching element connected parallel to the third switch means, a second switching element connected parallel to the fourth switch means, and signal generating means for controlling the first and second switching elements.

9. A camera according to claim 8, in which the signal generating means comprises an input terminal and is arranged to generate a signal for actuating the first and second switching elements when an outside signal is applied to the input terminal.