Motor-driven film winder for cameras

A motor-driven film winder for use with a camera having a manual film winder wheel, includes a cover selectively movable between a first position in which it prevents access to the manual film winder wheel and a second position in which the manual film winder wheel is exposed to permit manual film winding. In response to movement of the cover into its second position, the motor-driven film winder is disabled.

The present invention relates to a motor-driven film winder which is 
mountable on a camera body and selectively actuatable for either a manual 
film feed operation or an automatic film feed operation. 
There are known in the prior art many motor-driven film winders which 
automatically advance the film in cameras. One form of automatic film 
transport mechanism is disclosed in Japanese Utility Model Application No. 
57-58855 filed by the same applicant. According to the disclosed device, 
an independent motor-driven film winder is mounted on a camera body in 
meshing engagement with the manual film winder wheel of the camera. The 
motor-driven film winder then directly drives the manual film winder 
wheel. This motor-driven winder incorporates a serious disadvantage in 
that there is a danger that a finger may be caught by the portion of the 
film winder wheel which is left exposed for manual film feed operation. 
For safe automatic film feed, it is therefore necessary to cover that 
portion of the film winder wheel that projects outwardly from the camera 
body. It is obviously preferable to attach a film winder wheel cover to 
the motor-driven film winder so that the film winder wheel may be manually 
operated when the motor-driven film winder is detached from the camera 
body. With such an arrangement, the film can be manually advanced by use 
of the film winder wheel when the motor-driven winder is dismounted from 
the camera, and when the motor-driven film winder is mounted on the camera 
the film can be fed automatically without risk of injury. 
This arrangement, however, is not totally satisfactory, as manual winding 
is preferred when loading a roll of film so that the take-up spool of the 
camera can be freely adjusted. As a result, the motor-driven film winder 
must always be dismounted during film loading. In addition, motor-driven 
film winders often become inoperative during use of the camera and must 
therefore be removed before continuing use of the camera. Finally, 
inoperative motor-driven film winders are often employed as camera grips 
or handles. In this situation it is absolutely necessary to permit access 
to the winder wheel of the camera with the motor-driven film winder 
mounted thereto. 
It is an object of the present invention to provide a motor-driven film 
winder which may be used without risk of injury. 
Another object of the present invention is to provide a motor-driven film 
winder which permits access to the manual film winder without requiring 
its removal from the camera. 
Still another object of the present invention is to provide a motor-driven 
film winder for cameras which has apparatus for selectively covering the 
manual film winder of the camera. More specifically, it is an object of 
the invention to provide such a motor-driven film winder for cameras 
having a manual film winder wheel. 
A further object of the present invention is to provide a motor-driven film 
winder for cameras which includes a switch responsive to movement of a 
film winder wheel cover for disabling the motor-driven film winder. 
According to the present invention, a motor-driven film winder for use with 
a camera having a manual film winder includes a cover selectively movable 
between a first position in which the cover prevents access to the manual 
film winder and a second position in which the cover is retracted to 
permit access to the manual film winder. In response to movement of the 
cover to the second position, the motor of the automatic film winder is 
disabled. The motor-driven film winder permits manual film winding even 
when mounted on the camera and therefore can be used as a camera grip.

Referring now to FIG. 1, the present invention is particularly useful when 
combined with a camera having a manual film winder in the form of wheel 1. 
Wheel 1 is manually rotatable about its axis and is formed with exposed 
peripheral teeth. The camera also has an electric connector plate 1a 
having contacts A, B and C, and a screw hole 1b located in the camera body 
for attachment of a motor-driven film winder. 
FIG. 2 illustrates the motor-driven film winder 2 of the present invention 
mounted on the camera of FIG. 1, with the parts of the winder positioned 
for automatic motor-driven film feed operation. The motor-driven winder 2 
includes a ratchet wheel 2e driven by a motor, indicated by the reference 
character 2g in FIG. 4, to engage a pawl 2f mounted on a gear 2d. Gear 2d 
is in driven engagement with an idler gear 2c which meshes with the teeth 
of the manual film winder wheel 1. Upon actuation of the motor 2g, ratchet 
wheel 2e is rotated and drives gear 2d through pawl 2f. Gear 2d drives 
idler gear 2c which in turn drives the manual film winder wheel 1 to 
advance the film. During motor-driven film feed operation the manual film 
feed wheel 1 is covered by a movable cover 2a which shields the wheel 1 
from any physical contact with external objects such as an operator's 
finger. The motor-driven film winder 2 also has a switch 2b which connects 
the motor 2g to a power supply, indicated by the reference character 2h in 
FIG. 4, and is actuatable by the moveable cover 2a in a manner to be more 
fully described hereinbelow. 
Referring now to FIG. 3 the motor-driven winder 2 is shown mounted on the 
camera of FIG. 1, with the parts of the winder positioned for manual film 
feed operation. During manual operation, the cover 2a is moved into the 
housing of the winder 2 to expose the manual film winder wheel 1. 
Retraction of the cover 2a separates the contacts making up switch 2b to 
open the normally closed switch. Opening switch 2b disconnects the motor 
2g from the power supply 2h. As a result, the motor-driven film winder 2 
is disabled and the manual film winder wheel 1 is rendered accessible to 
the operator for manually feeding the film in the camera. The use of the 
idler gears 2c and 2d together with the ratchet wheel 2e and pawl 2f, 
insures that no rotative power is transmitted from the manual film winder 
wheel 1 to the motor 2g during the manual film winding operation. 
Therefore, the manual film winder wheel 1 may be turned about its own axis 
with no more than the normal amount of force used when the motor-driven 
film winder 2 is disconnected from the camera. 
Referring now specifically to FIG. 4, the circuit shown includes the motor 
2g, the switch 2b and the power source 2h, which may be a battery. 
Terminals A, B and C are connected to corresponding terminals A, B and C 
on the connector plate 1a of the camera. Switch 2b will remain closed as 
long as the cover 2a is in the position shown in FIG. 2, in which it 
prevents access to the wheel 1. Upon movement of the cover 2a to the 
position shown in FIG. 3, in which it permits access to the wheel 1, the 
contacts of switch 2b are separated to open the switch. 
As is known in the art, after a picture is taken, terminals A and C are 
coupled by circuit means internal to the camera to energize motor 2g. 
Motor 2g causes the film to advance to the next picture. After the film is 
advanced, terminal A is disconnected from terminal C and connected to 
terminal B to de-energize the motor until the next picture is taken. As 
long as cover 2a remains closed, switch 2b will remain closed, permitting 
energization of the motor 2g upon the connection of terminals A and C. 
Once the cover 2a is opened to permit access to the winder wheel 1, switch 
2b is opened, preventing energization of motor 2g under any circumstances. 
With the arrangement of the present invention, the camera may be used for 
manual or automatic film winding operations with the motor-driven film 
winder 2 mounted thereto. The manual film winding operation is selected in 
response to movement of cover 2a to the position shown in FIG. 3. In this 
position of the cover 2a, in which the wheel 1 is exposed, motor-driven 
operation of the wheel is prevented. 
As will be readily apparent to those skilled in the art, the invention may 
be used in other specific forms or for other purposes without departing 
from its spirit or central characteristics. The present embodiments are 
therefore to be considered as illustrative and not restrictive, the scope 
of the invention being indicated by the claims rather than by the 
foregoing description, and all embodiments which come within the range of 
equivalence of the claims are intended to be embraced.