Switching potentiometer control unit

In a potentiometer,

• a non-conductive planar base having a resistive strip formed thereon,
• a shaft,
• means mounting said shaft for rotation with its axis normal to said base,
• a wiper contact including an annular strip of highly conductive metallic material bent at diametrically opposite sides thereof to define first and second diametrically opposed dihedral angular portions, the opposite sides of which define first and second brush contact portions, and
• means mounting said wiper contact on said shaft with said brush contact portions facing said base.

In a control unit for controlling the power delivered to an electrical load from a supply of electrical energy,

• means for connecting the unit serially between the supply and the load,
• switching means for selectively making and breaking said series connection,
• impedance means having a maximum value for determining the minimum power delivered from the supply to the load when the switching means is actuated selectively to make the series connection,
• movable contact means selectively engagable with and rotatively positionable on said impedance means for selectively shunting a portion of said impedance means for varying the power delivered from the supply to the load, and
• common actuating means coupled to both said switching means and said movable contact for selectively disengaging said movable contact from said impedance means prior to operating said switching means without altering the rotative position of said movable contact means.

A snap action switching mechanism which comprises:

• an insulating housing having a supporting surface formed with an aperture therethrough;
• first and second spaced conductive elements supported on said surface on opposite sides of said aperture;
• an elongated conductive member formed with an aperture therethrough having first and second longitudinally spaced, inwardly projecting portions;
• means mounting said elongated conductive member in electrical contact with said first conductive element for pivotal movement about an axis in a plane spaced from said surface with said apertures aligned with one another;
• first resilient means interposed between one end of said elongated conductive member and a point in said plane spaced therefrom for selectively thrusting the opposite end of said elongated member into a first pivotal rest position in engagement with said second conductive element when said one end of said elongated conductive member is moved away from said surface past said plane, and into a second pivotal rest position disengaged from said second conductive element when said opposite end of said elongated conductive member is moved away from said surface past said plane;
• a shaft mounted for axial movement along an axis through said aligned apertures between a first position and a second position;
• second resilient means urging said shaft into said second position;
• a cylindrical camming member formed with first and second circumferentially spaced radial projections thereon;
• means loosely mounting said camming member on said shaft with said first radial projection aligned for engagement with said first projecting portion of said aperture in said elongated conductive member when said opposite end of said elongated conductive member is in said first pivotal rest position to move said opposite end of said elongated conductive member away from said base past said plane to thrust said opposite end of said elongated conductive member into said second pivotal rest position when said shaft is moved from said second position to said first position, and with said second radial projection aligned for engagement with said second projecting portion of said aperture in said elongated conductive member when said opposite end of said elongated conductive member is in said second pivotal rest position to move said one end of said elongated conductive member away from said base past said plane to thrust said opposite end of said elongated conductive member into said first pivotal rest position when said shaft is moved from said second position to said first position;
• and
• means for partially rotating said camming member about the axis of the said shaft when said shaft is moved from said first position to said second position, in a first direction to align said second radial projection for engagement with said second projecting portion of said aperture in said elongated conductive member when said opposite end of said elongated conductive member is in said second pivotal rest position, and in a second opposite direction to align said first radial projection for engagement with said first projecting portion of said aperture in said elongated conductive member when said opposite end of said elongated conductive member is in said first pivotal rest position.