US 3863195 A
A miniature linear resistor having a T-shaped base comprised of insulating material and a removable conductive slider that conductively engages conductive and resistive surfaces provided on the top and bottom edges of the top cross bar of the T. The vertical portion of the T is used to mount the assembly through conductive portions that connect to other components or the conductors of an electrical or electronic device. The conductive slider includes a contact and a resilient biasing means therefor.
Description (OCR text may contain errors)
States atent SLIDING VARIABLE RESISTOR Inventor: Jack L. Bowen, Wuscca, Minn.
Assigncc: E. F. Johnson Company, Wascca,
Filed: July 16, 1973 Appl. No.: 379,770
Related U.S. Application Data Continuation-in-part of Set. No. 289,657, Sept. 15, 1972, abandoned.
US. Cl. 338/183 Int. Cl. H010 9/02 Field of Search... 338/183, 176, 180
References Cited UNITED STATES PATENTS 10/1960 Barden et al. 338/180 1 Jan. 28, 1975 3588,77) 6/1971 Goerg 338/183 3,634,805 1/1972 Jestrzemski et al 338/180 Primary Examiner.l. V. Truhe Assistant ExaminerDavid A. Tone Attorney, Agent, or FirmWarren A. Sturm  ABSTRACT A miniature linear resistor having a T-shaped base comprised of insulating material and a removable conductive slider that conductively engages conductive and resistive surfaces provided on the top and bottom edges of the top crossbar of the T. The vertical portion of the T is used to mount the assembly through conductive portions that connect to other components or the conductors of an electrical or electronic device. The conductive slider includes a contact and a resilient biasing means therefor.
10 Claims, 10 Drawing Figures Patent ed Jan. 28, 1975 3,863,195
2 Sheets-Sheet l FIE:
Patented Jan. 28, 1975 3,863,195
SLIDING VARIABLE RESISTOR This is a continuation-in-part of an earlier filed, copending application in the name of Jack L. Bowen, having Ser. No. 289,657, filed Sept. 15, 1972, for SLID- ING VARIABLE RESISTOR now abandoned.
SUMMARY OF THE INVENTION It is an object of this invention to provide an improved linear variable resistor that, because of its simplicity, may be made in very small sizes and which will afford the reliability necessary in present day and future electrical and electronic apparatus.
My invention includes an elongated T-shaped base comprised of suitable insulating material. The top of the cross bar of the T is coated with a layer of suitable resistive material. The bottoms of the lower portion of the cross bar are coated with a layer of conductive material. At least one end of the base is coated with a conductive material that is in conductive engagement with one end of the layer of resistive material and which also serves as a terminal for connection to other devices. The conductive portions on the bottoms of the cross bar of the T-shaped base are likewise in conductive engagement with a further conductive coating on the other end or in an appropriate location on the base to form another terminal for connection to other devices.
A hollow slider has a pair of parallel spaced apart side walls that extend along the sides of the cross bar of the T-shaped base and then inwardly to slidably, conductively engage the conductive portions on the bottom of the cross bar. A conductive contact is disposed within the top of the slider so that its lower surface engages the top surface of the layer of resistive material and suitable biasing means are provided to exert a downward force thereon.
The relative location or size of the resistive and conductive coatings that are engaged by the slider may be varied to obtain desired operational characteristics.
BRIEF DESCRIPTION OF THE DRAWINGS I 4-4 on FIG. 1 of the drawing;
FIG. 5 is a sectional view taken along section line 5-5 on FIG. 2 of the drawing;
FIG. 6 is a perspective sketch of an alternative element of the device shown in FIGS. 1-5, inclusive;
FIG. 7 is a sectional view of the apparatus of FIG. 1' taken along section line 7-7 of the drawing illustrating a further embodiment of my invention in which an impedance element is shown having a characterization as is described below;
FIG. 8 is a top elevational view of another embodiment of my invention incorporating a sliding contact of modified form;
FIG. 9 is an enlarged fragmentary sectional view taken along section line 9-9 on FIG. 8 of the drawings; and
FIG. 10 is a sectional view of another embodiment of my invention taken along section line 10-10 on FIG. 1 of the drawing illustrating a characterized form of impedance at a further location on the variable resistor of my invention.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Referring now to FIGS. 1-5 of the drawings, there is shown a linear variable resistor indicated generally by reference character 10.
Resistor 10 includes aa T-shaped base 11 which may be constructed of any suitable insulating material, such as creamic, plastic or the like. T-shaped base member 11 is shown having conductive coatings l2 and 13 on the right and left ends respectively, and a further conductive coating 14 and 15 on the spaced apart bottom portions of the cross bar of the T-shaped base. The conductive coatings or strips 14 and 15 are conductively connected with coating 12 on the right end base 11. Base 11 is further provided with a coating of resistive material, 16, on the top of the cross bar of the base. The coating of resistive material may be of any thickness or shape or composition which will provide a desired characteristic and the selection of such material from those available is believed to be within the capabilities of one skilled in the art to which my invention pertains. Two illustrations of various configurations of resistive material are shown in FIGS. 7 and 10 to be de scribed in detail below.
In FIG. 1 of the drawings, base 11 is shown operatively disposed on the insulating base 30 of a typical printed wiring card or board which includes a pair of conductors 31 and 32 which, in a typical installation, would be connected to other electrical or electronic devices at their other extremities (not shown). Conductor 31 is shown connected to conductive coating 12 on base 11 by a solder fillet and likewise conductor 32 is shown connected to conductor 13 on the left end of base 11 by similar means. It should be clear that other types of connections or terminations may easily be provided depending upon the installation-desired.
While the illustrated embodiment of FIGS. 1-5 shows a base 11 adopted to provide a variableresistive effect intermediate the ends, other configurations will occur to those skilled in the art upon becoming aware of the principles of my invention, for example, the conductive coatings on the ends of base 11 may each be connected to the resistive coating 16 on the top and insulated from conductive strips 14 and 15 on the bottom of the cross bar and further conductive surfaces disposed intermediate the ends of T-shaped base 11 may be utilized to connect to conductive strips 14 and 15 whereby a potentiometer operation may be obtained.
A conductive slider 20 is shown slidably disposed on the cross bar of T-shaped base 1 1. Conductive slider 20 includes a pair of parallel spaced apart end portions 23 and 24 and a pair of parallel spaced apart side portions 25 and 26, each having bottom portions 27 and 28, respectively, extending inwardly thereof and generally parallel to the top surface of slider 20. It will be seen that slider 20 is hollow and that a slidable conductive contact 21 may be disposed therein in engagement with the top of resistive layer 16 on base 11 and is held in such conductive relationship by the action of a string bias element 22 shown in the form of an arcuate conductive spring which serves to exert a downward bias- 3 ing force on contact 21 through the coaction with the top of slider 20 and the bottom portions 27 and 28 of side portions 25 and 26 in engagement with conductive strips 14 and 15 on the bottom of the cross bar on base Slider 20 is preferably constructed entirely of conductive material, but it will be noted that it is only necessary to use such material to effect a sliding conductive relationship between conductive strips 14 and 15 and the top of conductive contact 21.
FIG. 6 illustrates a modified embodiment of conductive contact 21 and is comprised of a woven or mesh body of generally rectangular configuration which, when disposed within the top portion of slider 20 not only serves to provide a sliding conductive contact with resistive layer 16, but also exhibits the required degree of resiliency to maintain a biasing force as described above in the preferred embodiment.
It may be apparent to those skilled in the art that other configurations of arrangement of the several elements of the illustrated embodiment may be possible, for example, it is contemplated that strips 14 and 15 may be comprised of resistive material and layer 16 may be comprised of conductive material and that such layers may be characterized in width and may contain one or more discontinuities for specific applications.
Referring specifically to FIG. 7 of the drawings, an embodiment of my invention involving a characterized resistive element indicated by reference character 33 is shown with the element varying in width, and, as such, provides a different characteristic with regard to linear movement of slider 20 than that which may be obtained with the illustrated embodiment of FIGS. 1-5.
In similar manner, FIG. 10 illustrates a characterization of a resistive coating on the bottomportion of the main body of the variable sliding resistor of my invention in which width characterized layers-40 and 41 are disposed in place of the conductive elements 14 and 15 shown in FIGS. 1-5 of the drawings to coact with the bottom portions of slider 20. In the embodiment of FIG. 10, it is contemplated that the top layer formed on base 11 may be comprised of a suitable conductive material, such as metallic silver or the like.
In the embodiment of FIGS. 8 and 9, the modified form of slider is indicated generally by reference character 34 and includes a contact portion 35 which is disposed at the intersection of an X-shaped open portion .36 that is disposed on a sliding base similar to that of slider as far as the bottom portions are concerned, but which maintains the open configuration to provide a downwardly biasing force to maintain contact 35 in current conductive relationship with a thin strip of impedance or resistive element indicated by reference character 37. Resistive element 37 is connected to con ductors 32 and 31 on base 30 through the appropriate conductive coatings at the ends of base 11 shown as elements l3 and 12, respectively.
It may also be appreciated that the resistive elements may also be characterized in length as well as in width and thickness to provide the desired impedance or resistance characteristics required for any particular application, and that this may be determined by those skilled in the art to which my invention applies.
Having now therefore fully illustrated and described my invention, what I claim to be new and desire to protect by Letters Patent is:
1. A variable linear resistor comprising in combination;
a. an elongated base member comprised of insulating material and having first and second surfaces;
b. a layer of conductive material at least along portions of one of said surfaces adjacent opposed side edges thereof;
c. a layer of resistive material along at least a portion of the other of said surfaces;
d. conductive slider means movably disposed on said base, said slider means including a pair of parallel spaced apart side portions'disposed adjacent the side edges of said base and extending over one of the surfaces, and contact means including biasing means therefor, disposed within said slider mean and over the other of said surfaces. v
2. The apparatus of claim 1 in which the base is T- shaped and the surfaces are the top and bottom of the cross bar.
3. The apparatus of claim 2 in which the resistive layer is on the top surface.
4. The apparatus of claim 3 in which the resistive layer is of varying length.
5. The apparatus of claim 3 in which the resistive layer is of varying width.
6. The apparatus of claim 1 in which the layer of conductive material includes an arcuate surface.
7. The apparatus of claim 1 in which the resistive layer is of varying width.
8. The apparatus of claim 1 in which the resistive layer, is of varying length.
9. The apparatus of claim I in which the resistive layer varies in resistance with its width.
10. The apparatus of claim 1 in which the resistive layer varies in resistance with its length.