Motor-Operated Film Winding Apparatus

The present invention relates to motor-operated film winding apparatus for use with cameras in general and more particularly to an improved motor-operated film winding apparatus in which the degrading of power-supply performance is obviated.

Recently, there has been widely used film winding apparatus of the type operated by a motor, in which the motor is operated at a high speed with a high voltage applied to the motor when the film is wound continuously and, when the film is wound frame by frame, a low voltage is applied to the motor to operate the motor at a low speed, by switching the potential of the power source for the motor appropriately.

Conventionally, such switching of the potential of the power source is accomplished by utilizing a different number of batteries in each case. To be more specific, a high potential is obtained by utilizing all the batteries of the power source and a low potential is obtained by utilizing some limited number of particular batteries out of all the batteries.

However, when the batteries are used in the above-mentioned manner, such particular batteries tend to be exhausted more so that the internal resistances of the particular batteries increase. As a result, when the batteries having increased internal resistances are connected in series with the other batteries in order to turn the motor at a high speed, the total potential of the batteries is limited by the batteries having such increased internal resistances and this shortens the life of all the batteries employed in the camera.

It is therefore a general object of the present invention to provide a motor-operated film winding apparatus in which the exhausting of particular batteries, more than other batteries during the life of the batteries, is obviated.

Another object of the invention is to provide a power supply switching means, to attain the abovementioned object, which is capable of switching a different battery into circuit connections with the motor responsive to completion of each photographing cycle.

According to the invention, one embodiment of motor-operated film winding apparatus employs a power supply switching means comprising a rotary switch which connects the batteries one by one to the motor of the film winding apparatus whenever a single photographing cycle is finished. The photographing cycle is determined either by the finish of the winding of each frame of the film or by the finish of each shutter operation.

In another embodiment of the invention, the power supply switching means comprises two transistors and a flip-flop circuit. The respective transistors are connected to the respective batteries, and the respective batteries are connected to the motor alternately by the flip-flop circuit, which is inverted whenever a single photographing cycle is finished.

The foregoing and other feature of the invention will be more apparent from a further reading of the specification and claims and from the drawings in which:

FIG. 1 (a) is a schematic sectional side view of a main portion of a film winding apparatus according to the invention.

FIG. 1 (b) is a schematic sectional side view of a rotary switch to be employed in the film winding apparatus of FIG. 1 (a).

FIG. 1 (c) shows a circuit diagram of the film winding apparatus of FIG. (a).

FIG. 2 shows a circuit diagram of another embodiment of film winding apparatus according to the invention.

FIG. 3 shows a time chart of the signals applied to a flip-flop circuit and the manner of use of the batteries in the embodiment of FIG. 2.

Referring to FIG. 1 (a), there is shown a schematic sectional side view of a main portion of an embodiment of film winding apparatus for use with a camera according to the invention. FIG. 1 (b) partially shows a rotary switch to be employed in the film winding apparatus of FIG. 1 (a), and FIG. 1 (c) shows a circuit diagram for the film winding apparatus of FIG. 1 (a).

In FIG. 1 (a), reference numeral 1 represents a gear mounted on the driving shaft of a motor M. The gear 1 engages with an intermediate gear 2 so that it is connected to the driving side of a known ball sliding joint means 3. The ball sliding joint means 3 comprises a driving member 3a and a driven member 3b, which are in pressure contact with each other by spring means 3c, and a ball 3d disposed between the driving member 3a and the driven member 3b. At the position shown in FIG. 1 (a), one cycle of film winding operation is finished and a coupler 4 is stopped, but the motor M is not stopped. Therefore, an excessive load is applied to the driven member 3b so that the ball 3d is disengaged from a predetermined position of the driving member 3a. As a result, the driven member 3b is moved upwards in the axial direction of the driven member 3b as indicated by the arrow, moving away from the driving member 3a against the bias of the spring means 3c so that the rotating force of the driving means 3a is no longer transmitted to the driven member 3b. The driven member 3b of the ball sliding joint means 3 is connected to the coupler 4 to be connected to a film driving shaft (not shown) of the camera and applies the rotating force of the driving plate 3a to the film driving shaft so as to wind a film by one frame. The driven member 3b is disengaged from the driving member 3b whenever the film is wound by one frame. The completion of the winding of one frame of film and the disengagement of driven member 3b may be considered to be the completion of one photographic cycle of the camera. It is well known, however, that different cameras have different photographic cycles which may end with a shutter release or other function.

The movement of the driven member 3b in the axial direction thereof is transmitted to a rotary switch SW.sub.O through a lever 5 so that the switch SW.sub.O is turned. To be more specific, when the driven member 3b is moved in the axial direction thereof, the lever 5 is turned counterclockwise in FIG. 1 (a) against the bias of a spring 8. At the end of the rotary lever 5, there is provided a ratchet pawl 6. By the ratchet pawl 6 engaged with a pin 7b of a rotary disk 7a of the switch SW.sub.O, the rotary disk 7a is rotated clockwise by one step so that a rotary contact 7c disposed on the back side of the rotary disk 7a is caused to meet one pair of stationary contacts a.sub.1 and a.sub.3 or the other pair of stationary contacts a.sub.2 and a.sub.4.

Referring to FIG. 1 (c), whenever the film winding is performed frame by frame, the switch SW.sub.O is turned step by step. Assuming that a power source switch SWa is on and a speed choice switch SWb is set for "low speed," an electric current is supplied to the motor M from either a battery B.sub.1 or a battery B.sub.2. As shown in FIG. 1 (c), the rotary switch SW.sub.O is in the position for connecting the contact a.sub.2 to the contact a.sub.4, current flows to the motor M from the battery B.sub.2, and when the contact a.sub.1 is connected to the contact a.sub.3 by the rotary switch SW.sub.O, current flows to the motor M from the battery B.sub.1. When the film is wound by one frame, the power source switch SWa is turned off by switching means (not shown) so that the motor M is stopped.

When the speed choice switch SWb is set for "high speed," current is supplied to the motor M from both batteries B.sub.1 and B.sub.2 connected in series. In this case, the switching operation of the rotary switch SW.sub.O is also performed, but it becomes irrelevant to the operation of the speed choice switch SWb since the circuit of the rotary switch SW.sub.O is disconnected from the speed choice switch SWb, and the film is wound continuously. By opening the power source switch SWa by the switching means (not shown), the motor M is stopped.

FIG. 2 is a circuit diagram of another embodiment of the invention, in which the switches in FIG. 1 (c) are replaced by a flip-flop FF and transistors Q.sub.1 and Q.sub.2. In this embodiment, when the speed choice switch SWb is set for "low speed" and the power source switch SWa is turned on, the batteries B.sub.1 and B.sub.2 are connected to the motor M via the transistors Q.sub.1 and Q.sub.2 and the switch SW4. The transistors Q.sub.1 and Q.sub.2 are connected to two output terminals Q and Q of the flip-flop FF, respectively, and whenever the flip-flop FF is inverted, one terminal thereof which has been on is turned off, while the other terminal thereof which has been off is turned on. The flip-flop FF is inverted whenever a shutter operation finish signal P is applied to an input terminal .phi. of the flip-flop FF. Reference character B.sub.3 indicates a power source of the flip-flop FF.

On the other hand, when the speed choice switch SWb is set for "high speed," the batteries B.sub.1 and B.sub.2 are directly connected to the motor M so that the motor is immediately rotated when the power source switch SWa is turned on. In this case, the flip-flop FF is operated corresponding to the signal P, but the transistors Q.sub.1 and Q.sub.2 are disconnected from the batteries B.sub.1 and B.sub.2 and the motor M by the switch SW4.

FIG. 3 shows a time chart of the signals applied to the input terminal .phi. and to the output terminals Q and Q of the flip-flop FF, including the time chart indicating how the batteries B.sub.1 and B.sub.2 are used in the embodiment of FIG. 2 when the speed choice switch SWb is set for "low speed." In this case, the flip-flop is inverted whenever the signal applied to the input terminal, .phi., falls to zero and, at the same time, the batteries B.sub.1 and B.sub.2 are used alternately.

In the above-mentioned embodiment, two batteries are used at a time at the "high speed" and the two batteries are alternately used at the "low speed." However, when three or more batteries are employed at a time at the "high speed," this apparatus can be designed so as to divide the batteries into three or more groups and use each battery or each group of the batteries successively at the "low speed."

In the above-mentioned two embodiments, the switching of the use of the batteries is performed whenever the film winding operation is finished and the flip-flop and the transistors are operated whenever the shutter operation is finished. However, any combination of these operations can be employed.

In the embodiment of FIGS. 1 (a), 1 (b) and 1 (c), the ball sliding joint means is employed, but any means can be employed if its action is equivalent to that of the sliding ball clutch.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.