Patent Application
20170085013
A spring biased contact pin assembly is a device used in electronics to establish an electrical connection between two circuits. As used herein “spring biased contact pin assembly” refers to a cylindrical barrel containing a spring-loaded pin at either end. Each pin usually has a sharp point for making secure contact with one of the two circuits that are to be electrically connected.
One commercially available spring biased contact pin assembly is sold under the trademark “Pogo,” which is a U.S. federally registered trademark of Everett Charles Technologies (ECT).
A spring biased contact pin assembly includes a barrel member having a barrel wall defining an elongate internal cavity with a lower end and an upper end. The assembly also includes a lower or bottom plunger member reciprocally mounted in the internal cavity proximate the lower end of the internal cavity. A spring member is positioned in the internal cavity between the lower plunger member and the upper end of the internal cavity. A high electrical resistance spacer member is positioned in the internal cavity in contact with the lower plunger member and the spring member. Spring force exerted through the spacer member urges the lower plunger member into electrical contact with the barrel wall.
A method of transmitting electricity through an electrical contact assembly includes urging, with a high electrical resistance member, a plunger member against a wall of a barrel member in which the plunger member is reciprocally mounted.
The spring-biased contact pin assembly 10 includes a coil spring 20 having a lower end 22 and an upper end 24. The coil spring 20 is positioned in a barrel member 32 having a tubular wall 34 extending between a lower end 36 and an upper end 40. The tubular wall defines a barrel cavity 33.
As further shown by
When the contact pin assembly 10 is positioned between the two electrical circuits 14, 16, the coil spring 20 is placed in a compressed state. The coil spring 20 is slightly smaller in diameter than the diameter of the barrel cavity 33. There is sufficient clearance or “slop” between the barrel member tubular wall 34 and the coil spring 20, and also between the lower plunger pin 54 and the hole 39 in the lower end plate 38, to allow the plunger head 52 to be urged into a slightly skewed relationship with the tubular member cavity 33 by the compressed spring 20. The force with which the plunger head 52 is urged against the tubular wall 34 at contact point 70 is referred to in the art as the bias force or simply “bias.”
With a sufficient bias force, as shown by
As illustrated in
The spring-biased contact pin assembly 110 includes a coil spring 120 having a lower end 122 and an upper end 124. The coil spring 120 is positioned in a barrel member 132 having a tubular wall 134 defining a cylindrical barrel cavity 133 extending between a lower end 136 and an upper end 140. The barrel member 132 has a lower end plate 138 with a central hole 139 that is adapted to reciprocally receive a pin 154 extending from a lower plunger member 150. The lower plunger member 150 has a plunger head 152 with a slightly smaller diameter than the barrel member cavity 133. The plunger head 152 is fixedly attached to the pin 154.
As further shown by
A high resistance or completely nonconductive ball or sphere 180 is positioned inside the barrel member 132 between the spring 120 and the bottom plunger head 152. The bottom plunger head 152 has a top face contact surface 153, which may be a concave surface 156 in which the lowest point 155 thereof is laterally offset from the central longitudinal axis of the plunger head 152.
The high resistance ball 180 engages this plunger top face contact surface 153. A lower surface portion 181 of the ball 180 that contacts the low point 155 of the concave surface 153 is laterally offset from the longitudinal centerline of the plunger head 152. The ball 180 applies a downwardly and laterally outwardly directed bias force 183 to the plunger head 152, urging it into firm electrical contact, with a region 170 of the barrel member tubular sidewall 134. In one example embodiment the spring force urging the high resistance ball 180 against the top face contact surface 153 may be about 0.245N. An electrical current path 100 thus extends through the lower plunger member 150, the barrel wall 134 and the upper plunger member 160 that electrically connects the two circuit devices 112 and 116.
It will be appreciated that because the ball 180 is made from an electrically nonconductive or high resistance material such as ceramic there is little if any electrical current flow through the ball 180. Since there is virtually no current flow through the ball 180, there is also virtually no current flow through the coil spring 120. Thus, essentially all of the current flow between the bottom and top plunger members 150, 160 passes through the tubular sidewall 134 of the barrel member 132. As a result there is little or no heating of the spring 120 and thus no spring heating or damage.
As used in this disclosure, the terms “top,” “bottom,” “upper,” “lower” and similar terms are used in a relative sense to describe the positional relationship between the various components shown in the drawings. These terms are not used in an absolute sense to describe an orientation of an object with respect to a gravitational field, Thus, a “lower plunger member” as described in this specification and drawings is properly referred to as a “lower plunger member” in a spring-biased contact pin assembly such as shown in
Although certain embodiments of a spring biased contact pin assembly and methods of making and using a spring biased contact pin assembly have been expressly described in detail herein, other embodiments thereof will occur to those skilled in the art after reading this disclosure. It is intended that the language of the appended claims be broadly construed to cover such alternative embodiments, except as limited by the prior art.
