Apparatus for controlling contactor motion in a position sensor

#This invention relates to linear and rotary position sensors, and more particularly, to a spring device having first and second spring elements each of which include contact surfaces that are biased against the board to reduce relative motion of sensor finger elements relative to an ink strip.

#Several devices utilized in motor vehicles include components that wear after repeated use. A device having such components is a contact position sensor that detects the position of an object such as an armature. Referring to FIG. 1, portions of a linear position sensor 10 having a slider assembly 12 is shown. The slider assembly 12 is positioned adjacent a board 32 having first 28 and second 30 ink strips which may be resistive inks used in forming a sensing circuit for detecting position. In another configuration, one of the ink strips may be conductive and the other resistive.

#The slider assembly 12 includes a base 14 and a plunger 16 that is adapted to be received by an armature. The base 14 includes a center member 18 located between first 20 and second 22 arms which extend outwardly from the base 14 to form a substantially U-shaped configuration. The first 20 and second 22 arms include first 24 and second 26 finger elements which are adapted to contact the first 28 and second 30 ink strips, respectively, so as to form electrical contact. In use, the first 24 and second 26 finger elements move across the first 28 and second 30 ink strips in accordance with corresponding armature movement. This provides an output, such as a voltage output, which is proportional to the relative position of the first 24 and second 26 finger elements with respect to the first 28 and second 30 ink strips.

#FIG. 1 is a perspective view of portions of a linear position sensor.

#FIG. 2 is a side view of portions of a position sensor used in an exhaust gas recirculation valve for a motor vehicle.

#FIG. 3 is a perspective view of spring device for controlling relative motion in accordance with the present invention.

#While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail specific embodiments, with the understanding that the present disclosure is to be considered as an example of the principles of the invention and not intended to limit the invention to the specific embodiments shown and described. In the description below, like reference numerals are used to describe the same, similar or corresponding parts in the several views of FIGS. 1-4.

#Referring to FIG. 3, a spring device 34 for controlling relative motion in a position sensor 10 is shown. The device 34 includes an attachment member 36 that is affixed to the base 14. The attachment member 36 is located between first 38 and second 40 spring elements that extend outwardly from the attachment member 36. The first 38 and second 40 spring elements include first 42 and second 44 contact surfaces, respectively, each having an arcuate shape adapted for contacting portions of the board 32 that do not have ink. In one embodiment, the first 42 and second 44 contact surfaces contact an area adjacent the first 28 and second 30 ink strips, respectively. Alternatively, the center member 18 and the attachment member 36 may be fabricated by using a stamping process to form a one piece assembly. In another configuration, the spring device 34, center member 18 and first 20 and second 22 arms may also be fabricated as one piece assembly.

#The first 38 and second 40 spring elements are fabricated from a resilient material having spring properties. The first 38 and second 40 spring elements are positioned relative to the board 32 such that a spring force is exerted that biases the first 42 and second 44 contact surfaces against the board 32. In accordance with the present invention, this serves to increase the force that is exerted on the board 32, thus reducing relative motion between the first 24 and second 26 finger elements and the first 28 and second 30 ink strips, respectively. Further, the relative motion is reduced without increasing contact pressure between the first 24 and second 26 finger elements and the first 28 and second 30 ink strips, respectively, thus avoiding an increased ink wear rate.