US 5,291,177 AGranted

Variable resistor

AssigneeYung Chang Industrial Co., Ltd.

InventorKun-Low Chiu

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Abstract

A variable resistor includes a case inside which a rotatable member with a resistive element mounted thereon is disposed with a separate rotatable shaft running through a hole formed thereon, a stationary member with external leads attached thereon overlapping the rotatable member with the shaft further running therethrough and extending out thereof to be engaged by a turning knob. The stationary member is secured on the case to form a part thereof. The rotatable shaft is constituted by two segments, an upper segment and a lower segment. A spring is provided between the lower shaft segment and the case to bias the shaft to abut against the rotatable member with an annular flange formed on one end thereof so that when nubs which are formed on the annual flange respectively engage with the corresponding recesses formed on the rotatable member, the rotatable member will follow the rotation of the shaft. The spring is so selected that when the torque transmitted between the shaft and the rotatable member is greater than a pre-determined value, the engagement between the shaft and the rotatable member will be broken. The upper segment of the rotatable shaft is removable from the variable resistor and thus replaceable with a substitute having different configurations for different purposes.

Claims9

Dependent claims

A variable resistor comprising a case inside which a rotatable member having a resistive element mounted thereon is disposed and a stationary member which overlaps the rotatable member and has three leads extending therefrom, said stationary member being secured on said case by a securing means, said leads respectively in connection with said resistive element at different locations thereof and extending out of said case to serve as external terminals, said case having a stopper mounted therein in such a position that when the rotatable member is rotated to a pre-determined limit thereof, a projection formed on said rotatable member encounters said stopper and stopped thereby to limit the rotation of said rotatable member, wherein the improvements comprise:

said variable resistor further comprises a rotation shaft which has a first end disposed between said case and said rotatable member and a second end running through a central hole formed on said rotatable member and a central bore formed on said stationary member and protruding out of said central bore to be engaged by a turning knob for providing rotation thereto, said rotation shaft having an annual radial flange formed on the first end thereof and being rotatably disposed in such a way to have the annual flange thereof disengageably engage said rotatable member with a retaining means so that when said rotation shaft is rotated to have said projection of the rotatable member encounter said stopper and a further rotation is applied on said rotation shaft, said rotatable member disengages from said shaft.

Dependencies are inferred from the claim text.