Sprocket mechanism for cameras
AssigneeSinpo Optical Co., Ltd.
InventorsYeou-Fu Huang, Jong-Shing Lin
Life of this patent
Estimating the term…
Abstract
A sprocket mechanism for cameras includes a sprocket consisted of a body and a raised annular portion, a positioning plate fitted onto the sprocket, and an electrical switch located near the positioning plate. The sprocket body has two opposite pairs of pawls spaced suitably apart, and the raised annular portion has two notches provided at predetermined positions. When the sprocket rotates through 180 degrees, the electrical switch is caused to be on or off. A motor is caused to stop after an electrical signal is detected. At the same time, it can be determined that a frame of the film has been advanced and precisely positioned, and a counter is provided to display the number of frames advanced.
Claims3
A sprocket mechanism for cameras, comprising:
- a positioning plate mounted on a housing of a camera, said positioning plate having a through hole for receiving a sprocket;
- said sprocket, having a central annular hole for accommodating a transmission wheel;
- said transmission wheel having a gear at an upper side thereof for engagement with a transmission gear set of a motor;
- said transmission wheel having a shaft which extends from a bottom side thereof and is sized slightly smaller than that of said central annular hole of said sprocket;
- a resilient piece fitted onto said shaft, said resilient piece having a bottom side provided with a projection at one side thereof for insertably fixed onto said sprocket, wherein
- said sprocket is provided with two pairs of pawls spaced a suitable distance apart from one another and a raised annular portion on an upper side of a body thereof, said raised annular portion having two notches provided at predetermined positions;
- and an electrical switch is mounted at a predetermined position adjacent to said positioning plate, said electrical switch consisting of an upper spring strip and a lower spring strip, said upper spring strip having a contact portion at a front end thereof projecting above an upper periphery of said through hole of said positioning plate so that it is in a corresponding relationship to said second spring strip, said contact portion of said upper spring strip being urged upwardly by said body of said sprocket so that said electrical switch is in an OFF state, an electrical signal being detected by a microprocessor for stopping said motor, determining whether a frame has been properly advanced and precisely positioned, and a counter is actuated to display the number of film frames used.
Dependencies are inferred from the claim text.