MINIATURE POTENTIOMETER WITH STOP RIB AND SEALING MEANS
United States Patent 3750079
A miniature potentiometer including a housing having an integral internal rib forming a stop; a bottom plate assembly incorporating a resistance element and terminal contacts and having a groove receiving the rib and locking the bottom plate against rotation in the housing; and a rotatable carrier assembly carrying a contact spring engageable with the resistance element and having a projection engageable with the rib for limiting rotation of the carrier assembly.
US Patent References:
Variable resistance control
Barden - February 1966 - 3237140
ADJUSTABLE POTENTIOMETER
Scheel - February 1970 - 3497856
Variable resistance control
Van Benthuysen - November 1967 - 3355693
Potentiometer apparatus
Ferrell - April 1968 - 3377606
Adjustable resistor
Basket - April 1968 - 3380011
Variable resistance control
Barden - February 1966 - 3237140
ADJUSTABLE POTENTIOMETER
Scheel - February 1970 - 3497856
Variable resistance control
Van Benthuysen - November 1967 - 3355693
Potentiometer apparatus
Ferrell - April 1968 - 3377606
Adjustable resistor
Basket - April 1968 - 3380011
Inventors:
Scheiterbauer, Adolf R. (Munchen, DT)
Stickdorn, Helmut (Neubiberg, DT)
Stickdorn, Helmut (Neubiberg, DT)
Application Number:
05/204381
Publication Date:
07/31/1973
Filing Date:
12/02/1971
View Patent Images:
Export Citation:
Assignee:
The Bunker-Ramo Corporation (Oak Brook, IL)
Primary Class:
Other Classes:
338/174
International Classes:
H01C10/30; H01C10/00; H01C9/02; H01C5/02
Field of Search:
338/162-164,168,174,175,196,202
US Patent References:
| 3537056 | MINIATURE VARIABLE RESISTANCE CONTROL | October 1970 | Van Benthuysen |
Primary Examiner:
Schaefer, Robert K.
Assistant Examiner:
Tolin, Gerald P.
Parent Case Data:
This is a continuation, of application Ser. No. 36,077, filed May 11, 1970 now abandoned.
Claims:
We claim
1. A miniature potentiometer comprising:
2. The miniature potentiometer of claim 1 wherein said end element includes a circular series of indicia around the aperture including end limit indications,
3. The miniature potentiometer of claim 2 wherein said housing is internally cup-shaped,
4. The miniature potentiometer of claim 3 wherein said notch of said contactor is press-fitted on said boss of said carrier,
1. A miniature potentiometer comprising:
2. The miniature potentiometer of claim 1 wherein said end element includes a circular series of indicia around the aperture including end limit indications,
3. The miniature potentiometer of claim 2 wherein said housing is internally cup-shaped,
4. The miniature potentiometer of claim 3 wherein said notch of said contactor is press-fitted on said boss of said carrier,
Description:
OBJECTS OF THE INVENTION
A broad object of the invention is to provide a new construction of potentiometer of miniature scale.
Another and more specific object is to provide a miniature potentiometer that is of unusal accuracy in construction and functioning.
A still more specific object is to provide a miniature potentiometer of the character referred to in which the accuracy is produced at least partially by making the accurately interfitting parts.
Another object is to provide a miniature potentiometer of unusual accuracy of the character just referred to in which the accuracy is achieved at least partially by providing certain of the parts with interfitting relationship and thereby positively preventing them from displacement.
A still further object is to provide a miniature potentiometer in which certain of the parts are press fitted together for accurately relatively positioning them, and retention of them in such proper interfitted relation throughout additional use and functioning of the potentiometer.
An additional object is to provide a miniature potentiometer in which certain principal parts are of molded material, such as plastic, and which is provided with a novel design of conformations including recesses for reception of elements in the electrical circuit therein.
A further object of the invention is to provide a miniature potentiometer of the foregoing general character and made up of separate parts, and which are fitted together in a simple manner whereby unusual savings in labor are achieved in the assembly of the parts.
DESCRIPTION OF A PREFERRED EMBODIMENT
In the drawings:
FIG. 1 is a side view partially in section and partially in elevation, showing the miniature potentiometer of the present invention;
FIG. 2 is a top view of the potentiometer;
FIG. 3 is a face view of the carrier assembly taken at line 3--3 of FIG. 1;
FIG. 4 is a face view of the bottom plate assembly taken at line 4--4 of FIG. 1; and
FIG. 5 is a sectional view taken at line 5--5 of FIG. 4 and oriented according to FIG. 1.
Referring in detail to the accompanying drawings, the potentiometer of the invention is indicated as a whole at 10. As an indication of its miniature scale, it is noted that it is on the order of one-fourth inch in outer diameter. It includes a housing 12, a bottom plate 14, and a carrier 16. The bottom plate may be molded of plastic while the housing may be of aluminum.
The housing 12 includes a planar top element 18 and a cylindrical side wall 20 concentric with an axis 22, the top element having an aperture 24 also symmetrical with that axis. The top element 18 is provided with a circular series of indicia 25 including two end indicating elements 27 indicating limit positions in the setting of the potentiometer as described hereinbelow. The surrounding side wall is provided with an integral internal rib 26 extending from the top element 18 downwardly toward and into juxtaposition with but short of the lower open end 28 of the housing member. The rib is shown in cross section in FIG. 2. At the lower end of the side wall, and downwardly beyond the rib 26 is a circumferential internal groove 30 and downwardly beyond that groove is a terminal edge element 32 which in the final construction becomes an inclined flange as referred to hereinbelow.
The rotatable carrier 16 is incorporated in a carrier assembly 34 constituting a major component in the potentiometer. The carrier 16 includes an axial stud or shaft element 36 fitted in the aperture 24 and a body portion 38 of a radial dimension just short of the rib 26. Formed on the body portion is a nose or radial projection 40 which extends radially beyond the rib 26 and into proximity to the inner surface of the surrounding wall 20. Upon rotation of the carrier 16 the nose or projection 40 engages the rib 26 on one side or the other at opposite ends of its rotational movement, the rib providing a limiting stop for such rotation.
The carrier 16 is provided with an axial bore 42 for a purpose to be referred to hereinbelow. An O-ring gasket 44 of resilient material such as rubber, surrounds the stud 36 and is disposed between the body portion 38 of the carrier and the top element 18 of the housing.
The stud 36 on its upper or outer end is provided with a screwdriver slot 46 and an indicating arrow 48 cooperative with the indicia 25, 27.
Mounted on the carrier 34 is a contactor or contact spring 50 and for securing this contactor in place (FIG. 3) the carrier is provided with a concentric annular rib 52 and a boss 54 at the periphery thereof. The contactor includes a body portion 56 having a peripheral notch 58, and including a collar 60 and a resilient arcuate arm 62. The collar 60 is fitted on the rib 52 and the notch 58 receives the boss 54, both in a press fit, holding the contactor in place and the notch-boss relation positively presenting the contactor from circumferential displacement. The arcutate arm 62 preferably at a point diametrically opposite the notch 58 is provided with a finger 64 for engaging the coil as referred to hereinbelow. For a purpose to be referred to, the collar 60 of the contactor is at least as great in axial dimension as the rib 52.
The bottom plate 14 is included in an assembly 66 and includes a main body portion having a circumferential rib 70 fitted in the groove 30, an upstanding axial flange 72 preferably and for the most part circumferentially fitted snugly with the surrounding wall thereof. At one side the flange 72 has an axial boss or projection 74 (FIGS. 4,5) having an axial groove 76 therein receiving the rib 26, and forming a locking arrangement against rotation of the bottom plate relative to the housing.
The bottom plate includes a central upstanding stud 78 having a reduced shank 80 at its upper end fitted in the bore 42, and forming bearing means for the carrier 16, the conformation forming an annular shoulder 82.
In the assembly of the device the carrier assembly with the O-ring 44 thereon is first inserted into the housing and then the bottom plate assembly, and the previously straight flange 32 is now peened in around the rib 70 and cemented in place as at 28.
The bottom plate assembly includes a pickup ring 84 having a collar portion 86 fitted over the shank 80 and butted to the shoulder 82. It has an axial portion 88 fitted against the boss 78 and preferably in a groove 90 thereon, and a radial foot 92 fitted in a groove 94 (FIG. 4). A terminal contact element 96 has a head 98 electrically secured to the foot 92 and a shank 100 extended through a bore 102 in the bottom plate and cemented in place as indicated at 104 (FIG. 5).
A resistance element 106 in the form of a coil is formed into a circular shape and fitted in the bottom plate, within the flange 72 and cemented in place, the ends of the resistance element terminating adjacent to and on opposite sides of the boss projection 74. At the ends of the coils, are contact elements 108 (FIGS. 4 5) each having a curved element 110 electrically secured to the resistance element and a foot element 112 extending radially inwardly in a groove 114. The bottom plate assembly also includes a pair of terminal contacts 116 each including a head 118 electrically secured to the foot 112, and a shank 120 extending through an aperture 122 and secured in place by cement as at 122.
The resilient O-ring 44 biases the carrier assembly 16 downwardly into engagement with the bottom plate assembly 14 and specifically the collar 60 into firm electrical contact engagement with the collar 86 of the pickup ring 84. The terminal contacts 116 are adapted for connection with suitable conductors for putting the resistance element in circuit while the terminal contact 96 is adapted for incorporation in a circuit for contact engagement through the pickup ring 84 and the contactor 50, and thus the resistance element 106.
The user may apply a screwdriver to the slot 46 and rotate the carrier assembly 16 and thereby move the contactor 50 and finger 64 along the resistance element for the desired setting, and upon the setting of the carrier assembly according to the manual manipulation by the screwdriver, as referred to, the arrow 48 in cooperation with the indica 25 indicates the setting, while the terminal indicia elements 27 indicate respectively the minimum and maximum settings.
The shape and proportions of the three main constructional parts namely the housing, the carrier, and the bottom plate, are such that they are well adapted to fabricating techniques, whether molding or otherwise.
The rib 26 on the inner surface of the housing wall, and the cooperation therewith by the groove 76, accurately position the bottom plate assembly, and thus the resistance element 106, and the cross sectional shape of the rib and groove further assures accuracy despite the miniature dimensions encountered. Additionally, the nose or projection 40 in engaging the rib, accurately determines the terminal positions of adjusting movement of the carrier assembly. The contactor 50 and the pickup ring 84 are assured constant and firm contact engagement by the resilience of the O-ring 44. Additionally the resilience of the arcuate arm 62 of the contactor assures constant firm electrical contact engagement with the resistance element. The parts of the device are easily and quickly assembled, with minimum labor required, and consequent economy, and the smaller elements are firmly retained in place, such as the contactor 50 by virtue of its press fit with the central rib 52 and the boss 54 as well as the positive prevention of rotational displacement of the contactor, and further in the rigid securement of the resistance element and the terminal contacts.
A broad object of the invention is to provide a new construction of potentiometer of miniature scale.
Another and more specific object is to provide a miniature potentiometer that is of unusal accuracy in construction and functioning.
A still more specific object is to provide a miniature potentiometer of the character referred to in which the accuracy is produced at least partially by making the accurately interfitting parts.
Another object is to provide a miniature potentiometer of unusual accuracy of the character just referred to in which the accuracy is achieved at least partially by providing certain of the parts with interfitting relationship and thereby positively preventing them from displacement.
A still further object is to provide a miniature potentiometer in which certain of the parts are press fitted together for accurately relatively positioning them, and retention of them in such proper interfitted relation throughout additional use and functioning of the potentiometer.
An additional object is to provide a miniature potentiometer in which certain principal parts are of molded material, such as plastic, and which is provided with a novel design of conformations including recesses for reception of elements in the electrical circuit therein.
A further object of the invention is to provide a miniature potentiometer of the foregoing general character and made up of separate parts, and which are fitted together in a simple manner whereby unusual savings in labor are achieved in the assembly of the parts.
DESCRIPTION OF A PREFERRED EMBODIMENT
In the drawings:
FIG. 1 is a side view partially in section and partially in elevation, showing the miniature potentiometer of the present invention;
FIG. 2 is a top view of the potentiometer;
FIG. 3 is a face view of the carrier assembly taken at line 3--3 of FIG. 1;
FIG. 4 is a face view of the bottom plate assembly taken at line 4--4 of FIG. 1; and
FIG. 5 is a sectional view taken at line 5--5 of FIG. 4 and oriented according to FIG. 1.
Referring in detail to the accompanying drawings, the potentiometer of the invention is indicated as a whole at 10. As an indication of its miniature scale, it is noted that it is on the order of one-fourth inch in outer diameter. It includes a housing 12, a bottom plate 14, and a carrier 16. The bottom plate may be molded of plastic while the housing may be of aluminum.
The housing 12 includes a planar top element 18 and a cylindrical side wall 20 concentric with an axis 22, the top element having an aperture 24 also symmetrical with that axis. The top element 18 is provided with a circular series of indicia 25 including two end indicating elements 27 indicating limit positions in the setting of the potentiometer as described hereinbelow. The surrounding side wall is provided with an integral internal rib 26 extending from the top element 18 downwardly toward and into juxtaposition with but short of the lower open end 28 of the housing member. The rib is shown in cross section in FIG. 2. At the lower end of the side wall, and downwardly beyond the rib 26 is a circumferential internal groove 30 and downwardly beyond that groove is a terminal edge element 32 which in the final construction becomes an inclined flange as referred to hereinbelow.
The rotatable carrier 16 is incorporated in a carrier assembly 34 constituting a major component in the potentiometer. The carrier 16 includes an axial stud or shaft element 36 fitted in the aperture 24 and a body portion 38 of a radial dimension just short of the rib 26. Formed on the body portion is a nose or radial projection 40 which extends radially beyond the rib 26 and into proximity to the inner surface of the surrounding wall 20. Upon rotation of the carrier 16 the nose or projection 40 engages the rib 26 on one side or the other at opposite ends of its rotational movement, the rib providing a limiting stop for such rotation.
The carrier 16 is provided with an axial bore 42 for a purpose to be referred to hereinbelow. An O-ring gasket 44 of resilient material such as rubber, surrounds the stud 36 and is disposed between the body portion 38 of the carrier and the top element 18 of the housing.
The stud 36 on its upper or outer end is provided with a screwdriver slot 46 and an indicating arrow 48 cooperative with the indicia 25, 27.
Mounted on the carrier 34 is a contactor or contact spring 50 and for securing this contactor in place (FIG. 3) the carrier is provided with a concentric annular rib 52 and a boss 54 at the periphery thereof. The contactor includes a body portion 56 having a peripheral notch 58, and including a collar 60 and a resilient arcuate arm 62. The collar 60 is fitted on the rib 52 and the notch 58 receives the boss 54, both in a press fit, holding the contactor in place and the notch-boss relation positively presenting the contactor from circumferential displacement. The arcutate arm 62 preferably at a point diametrically opposite the notch 58 is provided with a finger 64 for engaging the coil as referred to hereinbelow. For a purpose to be referred to, the collar 60 of the contactor is at least as great in axial dimension as the rib 52.
The bottom plate 14 is included in an assembly 66 and includes a main body portion having a circumferential rib 70 fitted in the groove 30, an upstanding axial flange 72 preferably and for the most part circumferentially fitted snugly with the surrounding wall thereof. At one side the flange 72 has an axial boss or projection 74 (FIGS. 4,5) having an axial groove 76 therein receiving the rib 26, and forming a locking arrangement against rotation of the bottom plate relative to the housing.
The bottom plate includes a central upstanding stud 78 having a reduced shank 80 at its upper end fitted in the bore 42, and forming bearing means for the carrier 16, the conformation forming an annular shoulder 82.
In the assembly of the device the carrier assembly with the O-ring 44 thereon is first inserted into the housing and then the bottom plate assembly, and the previously straight flange 32 is now peened in around the rib 70 and cemented in place as at 28.
The bottom plate assembly includes a pickup ring 84 having a collar portion 86 fitted over the shank 80 and butted to the shoulder 82. It has an axial portion 88 fitted against the boss 78 and preferably in a groove 90 thereon, and a radial foot 92 fitted in a groove 94 (FIG. 4). A terminal contact element 96 has a head 98 electrically secured to the foot 92 and a shank 100 extended through a bore 102 in the bottom plate and cemented in place as indicated at 104 (FIG. 5).
A resistance element 106 in the form of a coil is formed into a circular shape and fitted in the bottom plate, within the flange 72 and cemented in place, the ends of the resistance element terminating adjacent to and on opposite sides of the boss projection 74. At the ends of the coils, are contact elements 108 (FIGS. 4 5) each having a curved element 110 electrically secured to the resistance element and a foot element 112 extending radially inwardly in a groove 114. The bottom plate assembly also includes a pair of terminal contacts 116 each including a head 118 electrically secured to the foot 112, and a shank 120 extending through an aperture 122 and secured in place by cement as at 122.
The resilient O-ring 44 biases the carrier assembly 16 downwardly into engagement with the bottom plate assembly 14 and specifically the collar 60 into firm electrical contact engagement with the collar 86 of the pickup ring 84. The terminal contacts 116 are adapted for connection with suitable conductors for putting the resistance element in circuit while the terminal contact 96 is adapted for incorporation in a circuit for contact engagement through the pickup ring 84 and the contactor 50, and thus the resistance element 106.
The user may apply a screwdriver to the slot 46 and rotate the carrier assembly 16 and thereby move the contactor 50 and finger 64 along the resistance element for the desired setting, and upon the setting of the carrier assembly according to the manual manipulation by the screwdriver, as referred to, the arrow 48 in cooperation with the indica 25 indicates the setting, while the terminal indicia elements 27 indicate respectively the minimum and maximum settings.
The shape and proportions of the three main constructional parts namely the housing, the carrier, and the bottom plate, are such that they are well adapted to fabricating techniques, whether molding or otherwise.
The rib 26 on the inner surface of the housing wall, and the cooperation therewith by the groove 76, accurately position the bottom plate assembly, and thus the resistance element 106, and the cross sectional shape of the rib and groove further assures accuracy despite the miniature dimensions encountered. Additionally, the nose or projection 40 in engaging the rib, accurately determines the terminal positions of adjusting movement of the carrier assembly. The contactor 50 and the pickup ring 84 are assured constant and firm contact engagement by the resilience of the O-ring 44. Additionally the resilience of the arcuate arm 62 of the contactor assures constant firm electrical contact engagement with the resistance element. The parts of the device are easily and quickly assembled, with minimum labor required, and consequent economy, and the smaller elements are firmly retained in place, such as the contactor 50 by virtue of its press fit with the central rib 52 and the boss 54 as well as the positive prevention of rotational displacement of the contactor, and further in the rigid securement of the resistance element and the terminal contacts.