Resistor card fuel level sender with float arm actuator

An easily-manufactured, stable, accurate fuel level sender for sensing the level of liquid fuel in a fuel tank, the sender having a plastic rheostat housing for connection to the interior of a fuel tank, a resistor card connected to the plastic housing and defining an arcuate path of variably-resistive conductive pads, positive and ground terminals mounted on the plastic housing, a float arm assembly rotatably connected to the plastic housing to rotate in a plane parallel to the resistor card in response to liquid fuel level changes in the tank, a plastic support arm connected to pivot with the float arm assembly about a common axis between the float arm and the plastic housing, a conductive wiper arm carried by the support arm to rotate with float arm assembly, the wiper arm having a resistor contact in continuous sliding contact with the resistor card arc and at least one ground contact in continuous sliding contact with the ground terminal, the improvement comprising:

• a first pivot bearing for the float arm assembly formed on the plastic housing below the plane of the resistor card;
• an axial thrust bearing surface formed in the plastic housing, the support arm rotatably mounted on the thrust bearing surface;
• a pair of spaced support posts formed on the plastic housing, the support posts providing a pair of support surfaces parallel to the plane of the resistor card and of the thrust bearing surface, the support surfaces located in a plane above the plane of the resistor card;
• the ground terminal mounted on the support surfaces of the support posts, the ground terminal defining a second pivot bearing for the float arm assembly above the plane of the resistor card, the second pivot bearing coaxial with the first pivot bearing, the wiper arm carried on the support arm between the support arm and the ground terminal.

An easily-manufactured, stable, accurate fuel level sender for sensing the level of liquid fuel in a fuel tank, the sender having a plastic rheostat housing for connection to the interior of a fuel tank, a resistor card connected to the plastic housing and defining an arcuate path of variably-resistive conductive pads, positive and ground terminals mounted on the plastic housing, a float arm assembly rotatably connected to the plastic housing to rotate in a plane parallel to the resistor card in response to liquid fuel level changes in the tank, a plastic support arm connected to pivot with the float arm assembly about a common axis between the float arm and the plastic housing, a conductive wiper arm carried by the support arm to rotate with float arm assembly, the wiper arm having a resistor contact in continuous sliding contact with the resistor card arc and at least one ground contact in continuous sliding contact with the ground terminal, the improvement comprising:

• a pair of spaced posts formed on the plastic housing of the fuel sender, the support posts having support surfaces parallel to the plane of the resistor card and the plane of rotation of the support arm, wiper arm and float arm assembly, the ground terminal comprising a plate-like element connected at each end to the support surfaces on the support posts, the ground terminal having a hole defining a pivot bearing aligned with the pivot axis of the float arm assembly, wiper arm and support arm, a pivot pin portion of the float arm assembly extending through the pivot bearing in the ground terminal, the wiper arm being sandwiched between a support surface on the support arm and the lower surface of the ground terminal with the ground contact of the wiper arm in constant contact with the lower surface of the ground terminal.

An easily-manufactured, stable, accurate fuel level sender for sensing the level of liquid fuel in a fuel tank, the sender having a plastic rheostat housing for connection to the interior of a fuel tank, a resistor card connected to the plastic housing and defining an arcuate path of variably-resistive conductive pads, positive and ground terminals mounted on the plastic housing, a float arm assembly rotatably connected to the plastic housing to rotate in a plane parallel to the resistor card in response to liquid fuel level changes in the tank, a plastic support arm connected to pivot with the float arm assembly about a common axis between the float arm and the plastic housing, a conductive wiper arm carried by the support arm to rotate with the float arm assembly, the wiper arm having a resistor contact in continuous sliding contact with the arcuate path of the resistor card and at least one ground contact in continuous sliding contact with the ground terminal, wherein the plastic housing forms a first pivot bearing for the float arm below the plane of the resistor card, and the ground terminal forms a second pivot bearing for the float arm above the plane of the resistor card to improve bearing stability, the rheostat housing including a plurality of curved and tapered locking tabs which deform to receive the resistor card in a snap-fit relative to the housing, the locking tabs comprising a first set of locking tabs engaging a first side of the resistor card, and second set of locking tabs engaging an opposite side of the resistor card, the tips of the first set of locking tabs initially engaging the top surface of the resistor card upon assembly in deformable manner, and the second set of locking tabs subsequently engaging the top surface and edge surface of the resistor card in a non-deformable fit.