A variable resistor includes an elongated housing, a dielectric base which supports elongated resistive and conductive strips, and a cover member. An elongated guide rail is mounted on the dielectric base and extends parallel to the resistive and conductive strips. A slider or carrier is provided with a groove at the lower surface thereof for slidably engaging the upper surface of the guide rail of the base. A control member is connected to the upper end of the slider and projects through an elongated slot in the cover member. A resilient member is so positioned between an upper surface of the slider and the inner surface of the top wall of the cover member that the slider is pushed evenly onto the guide rail. Thus, when the position of the slider is altered by the control member, the sliding contacts are moved evenly along the resistive and conductive elements without skipping, jumping or derailing therefrom. The present invention relates to a variable resistor and control device therefor and particularly to a variable resistor of the type having a slider movable rectilinearly in the housing. Variable resistors of the type herein described provide for a contact adapted to slidingly engage elongated resistive and conductive strips mounted on an elongated insulating base. Typically the slider mechanism is supported in a housing having side walls and a slotted top through which the slider control member extends. Resistors of this type are particularly well adapted for use in adjustable volume control mechanisms and communication receivers, but its use is not so limited. It is imperative for successful operation of such variable resistor devices that the slider contacts have a smooth sliding engagement with the conductive and resistive strips along the entire length thereof. In currently available devices of this type the path of the slider mechanism is defined by the inner side walls of the housing within which it is confined. Because of the limitations on the manufacturing process and the possibility of deformation during assembly, a tight sliding fit between the slider and the housing is not commercially feasible. As a result the device is generally designed and produced with substantial clearance between the housing side walls and the slider. As a consequence of this clearance and of such deformation or imperfection in the housing side walls as may result from the manufacturing or assembling process, the slider movement may be erratic to the extent that the contacts may run off the resistive and conductive strips. A second problem usually encountered in the design of devices of this type is maintaining the contacts in firm electrical engagement. Normally the operative slider contacts are forced into engagement with the resistive and conductive strips by the top wall of the housing. Again, however, any deformation or imperfection in the top wall, the insulating base or the operative strips themselves may result in skipping or jumping of the slider contacts as they move along their respective strips. Conventional methods of dealing with this problem have generally been unsatisfactory. Thus, if the slider is sandwiched relatively tightly between the top wall of the housing and the base, the slider becomes difficult to move and slight imperfections in the various parts may result in sticking and severe wear on the sliding surfaces of the various parts. If, on the other hand, a substantial vertical clearance is provided and electrical contact is maintained by sufficient pressure on the vertically extending control member, the slider tends to rock to and fro as pressure is exerted on the control member in the longitudinal direction. While the foregoing difficulties could, to a large extent, be eliminated by the manufacture of the various parts to rather close tolerances, this alternative is generally not commercially feasible in view of the greatly increased manufacturing costs involved. Accordingly, it is a primary object of the present invention to design a new and improved variable resistor of the type described which effectively eliminates the foregoing difficulties with no substantial increase in manufacturing costs. It is another object of the present invention to design a variable resistor device having an improved slider mechanism which insures adequate sliding electrical contact along the entire length of the device regardless of deformities or imperfections in the housing or base members. It is yet another object of the present invention to provide an improved variable resistor device of the sliding contact type which provides smooth and uniform slider movement without skipping, jumping or derailment of the sliding contacts on the operative conductive and resistive strips. It is still a further object of the present invention to provide a variable resistor device with improved operating characteristics and reliability even under adverse conditions such as rough or careless handling and/or assembly. To these ends, in accordance with a preferred embodiment of the invention, there is provided an inverted U-shaped housing having a top wall provided with an elongated slot. The housing is operatively connected to an insulating base at its open face to thereby form an elongated enclosure adapted to slidingly receive a slide or carrier. The base includes one or more resistance elements printed on a surface thereof and extending lengthwise thereof, and a corresponding number of elongated conductive elements secured on the base surface and extending parallel to and spaced from the resistance elements. An elongated guide rail is mounted on the surface of the base and extends parallel to the resistive and conductive elements. The slider or carrier is made of an insulating material and is provided with a groove at its lower surface adapted to slidingly engage the guide rail. A pair of resilient contactors are secured to the aforesaid lower surface and include contacts wipably engaging the resistive and conductive elements. The device is adapted to be actuated by a control member having one end secured to the slider and the other end projecting through the elongated slot in the top of the housing. A resilient member is provided between an upper surface of the slider and the inner surface of the top wall of housing for maintaining the slider mounted on the guide rail and providing a smooth even sliding engagement between the contacts and the conductive and resistive elements.

A slide rheostat wherein a movable insulating plate and a leaf spring which are centrally provided with holes for receiving a lever of a slide piece receiver are made unitary by mounting a flat portion of the leaf spring on the movable insulating plate by outsert molding, the unitary movable insulating plate and leaf spring have the lever inserted therethrough. Resilient protuberant pieces are disposed at the four corners of the flat portion of the leaf spring and held in resilient contact with the upper surface of the slide piece receiver, and the movable insulating plate is held in resilient contact with the upper rear surface of a case through the action of the leaf spring.