Method of making a variable resistor

Claim 2

In a method of makinG a variable resistor having a housing member formed with a pair of spaced end walls connected to a side wall, one of said end walls having a cylindrical aperture formed therein, and a metal adjustment member formed with a circular cross-section head, a threaded shank and a circular cross-section tip on the end opposite the head thereof, the steps including: A. inserting the adjustment member, tip first, from the exterior of the housing member through the cylindrical aperture in the one end wall of the housing; B. inserting a fixture into an open side of the housing member opposite said side wall into engagement with the adjustment member to position the adjustment member in the desired position between the fixture and the side wall of the housing member; C. ultrasonically vibrating the adjustment member relative to the housing member while simultaneously exerting axial force between the adjustment and housing members to drive the head of the adjustment member into the cylindrical aperture in said one end wall of the housing member until the circular cross-section tip of the adjustment member penetrates a substantial extent into the other of said spaced end walls of the housing member, thereby causing the thermoplastic material of said one end wall of the housing member to soften and flow about the head of the adjustment member and causing the thermoplastic material of said other end wall of the housing to simultaneously soften and flow about the tip of the adjustment member; D. discontinuing the ultrasonic vibration and allowing the thermoplastic housing material to solidify about the region of the head and about the tip of the adjustment member whereby a front and a rear journal are simultaneously formed to rotatably support the adjustment member in the desired position in the housing member; and E. thereafter withdrawing the fixture from the housing member.

Claim 3

A method of forming a variable resistor as defined in claim 1 including the step of forming a concave groove in said side wall of the housing member for assisting in locating the adjustment member in the desired position relative thereto.

Claim 4

In a method of making a variable resistor having a hollow housing member with an open side formed by a pair of spaced end walls connected by three side walls, one of said end walls having a cylindrical aperture formed therein; a metal adjustment screw member formed with a head having at least one annular rib therein of a diameter greater than the diameter of the cylindrical aperture formed in said one end wall of the housing member, said adjustment screw member also having a threaded shank and having a conically pointed tip on the end opposite the head thereof; and a substrate member carrying an electrical resistance element, the steps including: A. inserting the adjustment screw member, tip first, from the exterior of the housing member through the cylindrical aperture in the one end wall of the housing until a portion of the adjustment screw engages the housing and prevents further insertion; B. placing the housing member in a housing fixture to hold the housing in a desired position; C. inserting a second fixture into the open side of the housing member into engagement with the adjustment screw member to position the adjustment screw member in the desired position between the second fixture and one of the side walls of the housing member; D. ultrasonically vibrating the adjustment screw member relative to the housing member while simultaneously exerting axial force between the adjustment screw and housing members to drive the head of the adjustment screw member into the cylindrical aperture in said one end wall of the housing member until the conically pointed tip of the adjustment screw member penetrates a substantial extent into the other of said spaced end walls, thereby causing the thermoplastic material of said one end wall of the housing member to soften and flow about the rib on the head of the adjustment scrEw member and causing the thermoplastic material of said other end wall of the housing to simultaneously soften and flow about the conical tip of the adjustment screw member; E. discontinuing the ultrasonic vibration and allowing the thermoplastic housing material to solidify about the region of the rib on the head and about the conical tip of the adjustment screw member whereby a front and a rear journal are simultaneously formed to rotatably support the adjustment screw member in the desired position in the housing; F. thereafter withdrawing the second fixture from the housing member; G. assembling a resistance element wiper member with the adjustment member for movement in the housing by rotation of the adjustment member; H. thereafter covering the open side of the housing member by assembling a substrate member, having a resistance element lying on the interior surface thereof, over the open side of the housing member with the resistance element in contact with the wiper member; and I. securing the substrate member to the housing member.

Claim 5

In a method of making a variable resistor having a hollow housing member with an open side formed by a pair of spaced end walls connected by three side walls, one of said end walls having a cylindrical aperture formed therein; a metal adjustment screw member formed with a head having at least one annular rib therein of a diameter greater than the diameter of the cylindrical aperture formed in said one end wall of the housing member, said adjustment screw member also having a threaded shank and having a conically pointed tip on the end opposite the head thereof; and a substrate member carrying an electrical resistance element, the steps including: A. inserting the adjustment screw member, tip first, from the exterior of the housing member through the cylindrical aperture in the one end wall of the housing until a portion of the adjustment screw engages the housing and prevents further insertion; B. placing the housing member in a housing fixture to hold the housing in a desired position; C. inserting a second fixture into the open side of the housing member into engagement with the adjustment screw member to position the adjustment screw member in the desired position between the second fixture and one of the side walls of the housing member; D. ultrasonically vibrating the adjustment screw member relative to the housing member while simultaneously exerting axial force between the adjustment screw and housing members to drive the head of the adjustment screw member into the cylindrical aperture in said one end wall of the housing member until the conically pointed tip of the adjustment screw member penetrates a substantial extent into the other of said spaced end walls, thereby causing the thermoplastic material of said one end wall of the housing member to soften and flow about the rib on the head of the adjustment scrEw member and causing the thermoplastic material of said other end wall of the housing to simultaneously soften and flow about the conical tip of the adjustment screw member; E. discontinuing the ultrasonic vibration and allowing the thermoplastic housing material to solidify about the region of the rib on the head and about the conical tip of the adjustment screw member whereby a front and a rear journal are simultaneously formed to rotatably support the adjustment screw member in the desired position in the housing; F. thereafter withdrawing the second fixture from the housing member; G. assembling a resistance element wiper member with the adjustment member for movement in the housing by rotation of the adjustment member; H. thereafter covering the open side of the housing member by assembling a substrate member, having a resistance element lying on the interior surface thereof, over the open side of the housing member with the resistance element in contact with the wiper member; and I. securing the substrate member to the housing member.

Claim 6

A method of making a variable resistor as defined in claim 3 wherein the step of securing the substrate member to the housing member includes ultrasonically deforming a portion of the housing member into engagement with the exterior surface of the substrate member lying outwardly of the interior cavity in the housing member.

Claim 7

A method of making a variable resistor as defined in claim 3 wherein the step of securing the substrate member to the housing member includes ultrasonically deforming a portion of the housing member into engagement with the exterior surface of the substrate member lying outwardly of the interior cavity in the housing member, and thereafter sealing the substrate member with the housing member by flowing and solidifying a potting agent over said exterior surface of the substrate member.