Abstract A non-contacting rotary type mode switch for a magnetic tape recording device such as VCR, in which a plurality of reflector pieces are arranged on tracks of a plurality of concentric circles respectively on the rear surface of a mode switch gear, and a plurality of opto-reflection sensor units composed of a light emitter and light receiver for discriminating the presence or absence of the reflector pieces, arranged on the top surface of a switch body, so that the rotational mode of said cam gear, i.e. running state, such as play, review, normal or reverse speed winding, stop and the like can be read out. Since the non-contacting type system utilizing the reflector pieces and opto-reflection sensor units are employed instead of the conventional contacting type, various disadvantages such as mechanical abrasion, deformation, leakage of lubricating oil, and electric discharging are eliminated, and also the system can be miniaturized.
A non-contacting rotary type mode switch system for a magnetic tape recording device, said non-contacting rotary type mode switch system comprising: a mode switch body, a axle pin mounted on the center portion of said mode switch body, a cam gear having a pinion at the center portion of lower surface thereof and a circular groove at a circumference thereof, whereby the cam gear is rotatably fixed t the upper portion around the axle pin, a mode switch gear mounted on said mode switch body for moving cooperatively with said cam gear for mode shifting rotatably about said axle pin so as to be positioned at the upper part of the mode switch gear, said mode switch gear having an internal gear at the internal peripheral circumference of the top surface thereof, a planetary gear meshed between said pinion of said cam gear and said internal gear of said mode switch gear, a plurality of reflector pieces formed on tracks of a plurality of concentric circles, respectively, which are arranged on the rear surface of said mode switch gear, and a plurality of opto-reflection sensors mounted on the top surface of said switch body for reading out the rotational mode of said cam gear, said each opto-reflection sensor including: light emitting means for emitting the light, and light receiving means for detecting the light reflected from said corresponding reflector piece.
Claim 2
Dependent Claim
230 words
A non-contacting rotary type mode switch system for a magnetic tape recording device, said non-contacting rotary type mode switch system comprising: a mode switch body, a axle pin mounted on the center portion of said mode switch body, a cam gear having a pinion at the center portion of lower surface thereof and a circular groove at a circumference thereof, whereby the cam gear is rotatably fixed t the upper portion around the axle pin, a mode switch gear mounted on said mode switch body for moving cooperatively with said cam gear for mode shifting rotatably about said axle pin so as to be positioned at the upper part of the mode switch gear, said mode switch gear having an internal gear at the internal peripheral circumference of the top surface thereof, a planetary gear meshed between said pinion of said cam gear and said internal gear of said mode switch gear, a plurality of reflector pieces formed on tracks of a plurality of concentric circles, respectively, which are arranged on the rear surface of said mode switch gear, and a plurality of opto-reflection sensors mounted on the top surface of said switch body for reading out the rotational mode of said cam gear, said each opto-reflection sensor including: light emitting means for emitting the light, and light receiving means for detecting the light reflected from said corresponding reflector piece.