U.S. patent number 3,809,830 [Application Number 05/340,414] was granted by the patent office on 1974-05-07 for sealed thumbwheel selector switch.
This patent grant is currently assigned to AMP Incorporated. Invention is credited to Joseph Larue Lockard, William Henry Rose.
United States Patent |
3,809,830 |
Lockard , et al. |
May 7, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
SEALED THUMBWHEEL SELECTOR SWITCH
Abstract
A thumb selector switch structure is disclosed which is
particularly suitable for use in corrosive or dusty environments.
The selector switch includes a printed circuit panel having an
angularly encoded conductive pattern printed thereon. A rotatable
contact carrying indicia wheel is rotatably mounted to the printed
circuit panel so that the contacts carried by the indicia wheel
selectively engage various portions of the angularly encoded
printed circuit pattern, thereby producing digital output signals
in response to the rotation of the contact carrying wheel. The
contact carrying wheel is permanently hermetically sealed to the
printed circuit board by means of a clear plastic casing. An
actuator wheel is provided for rotating the indicia and contact
carrying wheel. A suitable housing having a detent spring mounted
therein is provided to enclose the above described structure.
Inventors: |
Lockard; Joseph Larue
(Harrisburg, PA), Rose; William Henry (Harrisburg, PA) |
Assignee: |
AMP Incorporated (Harrisburg,
PA)
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Family
ID: |
26944992 |
Appl.
No.: |
05/340,414 |
Filed: |
March 12, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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255844 |
May 22, 1972 |
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Current U.S.
Class: |
200/11TW;
200/302.1; 200/308 |
Current CPC
Class: |
H01H
19/001 (20130101); G01D 5/25 (20130101); H01H
19/06 (20130101) |
Current International
Class: |
H01H
19/06 (20060101); G01D 5/12 (20060101); G01D
5/25 (20060101); H01H 19/00 (20060101); H01h
019/58 (); H01h 009/04 () |
Field of
Search: |
;200/11TW,167R,167A,168G,168K |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Scott; James R.
Attorney, Agent or Firm: Kita; Gerald K.
Parent Case Text
This application is a continuation-in-part of application Ser. No.
255,844, filed May 22, 1972, and now abandoned.
Claims
1. A rotary switch, comprising: a housing of electrical insulation
material, a thumb wheel mounted for rotation in said housing and
having projecting portions exposed through said housing and adapted
to be manually engaged for rotation of said thumb wheel, a printed
circuit board mounted generally in said housing and having a
plurality of electrical circuit paths thereon, a cover having a
cavity portion, a wheel having electrical contact fingers
protruding therefrom, said wheel being mounted for rotation in said
cavity portion of said cover, said cover overlying at least
portions of said electrical circuit paths, said electrical contact
fingers projecting towards said portions of said electrical circuit
paths for making selective engagement therewith upon rotation of
said wheel to selected positions, sealing means sandwiched between
said cover and said circuit board, thereby sealably enclosing said
portions of said electrical circuit paths and said wheel and said
contact fingers between said cover and said printed circuit board,
a rotary shaft connecting said thumb wheel and said wheel for
simultaneous rotation, said cavity portion having an aperture
therethrough, said shaft protruding through said aperture in said
cavity portion, and a sealing ring encircling said shaft and
sealing said
2. The structure as recited in claim 1, wherein, said wheel is
provided with a cylindrical surface having indicia thereon
indicative of the
3. The structure as recited in claim 1, wherein, said cavity
portion includes a hollow cylindrical portion receiving said
sealing ring, and said sealing ring is compressed between said
hollow cylindrical portion of said cavity portion and said thumb
wheel to provide a seal for said
4. The structure as recited in claim 1, and further including: a
resilient spring mounted in said housing and engageable on said
thumbwheel to
5. The structure as recited in claim 1, and further including:
additional portions of said circuit paths protruding from said
cover to provide electrical leads externally of said cover, said
cover sealably overlying
6. A rotary switch, comprising: a housing, a printed circuit board
received substantially in said housing and having electrical
circuit paths thereon, a rotatable wheel received in said housing
and having indicia thereon about the periphery thereof, said wheel
further being provided with electrical contact fingers extending
therefrom for electrical engagement on selected ones of said
circuit paths upon rotation of said wheel to selected positions,
means received in said housing for rotating said cylindrical wheel
to selected positions, a cover received in said housing and mounted
on said printed circuit board, said cover being enclosed over said
cylindrical wheel and said contact fingers and at least portions of
said circuit paths which extend between said cover and said printed
circuit board, and sealing means providing a seal between said
cover and
7. The structure as recited in claim 6, wherein, said printed
circuit board projects externally of said cover, said circuit paths
include additional portions thereof on said printed circuit board
protruding externally of said cover to provide electrical leads,
said cover sealably overlying said
8. A rotary switch, comprising: a housing, a thumbwheel received in
said housing and being rotatable to selected positions, detent
means in said housing and engageable on said thumbwheel for
retaining said thumbwheel in at least one of said selected
positions, a printed circuit board having a plurality of electrical
circuit paths thereon, the printed circuit board being mounted
generally interiorly of said housing, a cover within said housing
and mounted directly on said printed circuit board and enclosing at
least portions of said circuit paths, a rotatable member contained
between said cover and said printed circuit board, said rotatable
member having a plurality of electrical contact fingers thereon
projecting toward said electrical circuit paths and being
engageable on selected ones of said circuit paths upon rotation of
said rotatable member to selected positions, said cover being
sealably retained fixedly against at least a portion of said
printed circuit board and sealably containing said rotatable member
and said contact fingers and at least portions of said circuit
paths between said cover and said printed circuit board, electrical
leads connected to said circuit paths and protruding from said
cover, and coupling means coupling said rotatable member to
said
9. The structure as recited in claim 8, wherein, said rotatable
member includes a generally cylindrical surface having indicia
thereon indicative
10. The structure as recited in claim 8, and further including:
additional portions of said electrical circuit paths on said
printed circuit board protruding from said cover to form said
electrical leads, said cover sealably engaging and overlying across
said additional portions of said
11. The structure as recited in claim 8, wherein, said
last-mentioned coupling means includes a rotatable shaft coupling
said thumbwheel and said rotatable member for simultaneous
rotation, said shaft protruding through an opening in said cover
and extending between said thumbwheel and said rotatable member,
and further including: a sealing ring encircling said shaft and
covering said opening in said cover, said sealing ring being
compressed between said thumbwheel and said cover and thereby
12. The structure as recited in claim 8, wherein, said rotatable
member comprises an electrically conducting contact having at least
some of said
13. The structure as recited in claim 12, wherein said coupling
means includes both a wheel to which said contact is attached and a
shaft
14. In a rotary switch having a housing, a thumbwheel mounted for
rotation in said housing with manually engageable portions of the
thumbwheel protruding from said housing, a printed circuit board in
said housing and electrical contact fingers engageable on selected
ones of a plurality of printed circuit paths on said printed
circuit board upon rotation of said thumbwheel to selected
positions, the improvement comprising: a covering panel sealably
enclosing said electrical contact fingers and being sealably
received against said printed circuit board, said thumbwheel
15. The structure as recited in claim 14, and further including: a
wheel, a rotatable shaft connecting said thumbwheel and wheel, said
wheel supporting said contact fingers, said covering panel having
an aperture receiving said shaft therethrough, said sealing means
for sealing said
16. The structure as recited in claim 15, wherein, said sealing
means includes a sealing ring encircling the periphery of said
shaft and in compression between said covering panel and said
thumbwheel to form a compression seal for sealing said aperture
about the periphery of said
17. The structure as recited in claim 14, wherein, said contact
fingers are mounted on a rotatable wheel enclosed within said
covering panel, said rotatable wheel being rotatably received
within said covering panel and
18. The structure as recited in claim 17, wherein, said rotatable
wheel is generally cylindrical with the contact fingers projecting
from an end thereof, a cylindrical surface of said wheel having
indicia thereon
19. The structure as recited in claim 14, wherein, said covering
panel is secured directly to said printed circuit board with
portions of said printed circuit board protruding from said
covering panel, said circuit paths on said protruding portions of
said printed circuit board extending from said covering panel to
provide electrical leads, said covering panel
20. The structure as recited in claim 14, and further including:
detent means in said housing for engaging and retaining said
thumbwheel momentarily in one of said selected positions.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to rotatable indicator switch
structures, and more particularly to a sealed, thumb actuated
rotary indicating switch.
2. Description of the Prior Art
At the present time a substantial need exists for a small, compact,
reliable thumb actuated selector switch which can be conveniently
and inexpensively mass produced without impairing its quality. A
thumb selector switch which has been highly satisfactory in meeting
these requirements is disclosed in U.S. Pat. No. 3,665,127 to
Joseph L. Lockard and William H. Rose, filed Feb. 26, 1971, and
assigned to the same assignee as the present application. However,
while the thumb selector switch disclosed in the above noted patent
was found to be most reliable and desirable for use in certain
environments, it possessed a disadvantage in that its contact
structure was exposed to the atmosphere. Accordingly, when exposed
to particularly harsh conditions, such as salty sea air,
particularly humid tropical weather or air containing high
concentrations of corrosive chemicals, it was found that corrosion
could develop in the contact and printed circuit board assembly of
the switch. In addition, in particularly dirt or dust laden
atmospheres, dust particles could enter the contact and printed
circuit board assembly of the above described thumb selector
switch, resulting in abrasive wear to the contact and printed
circuit board assembly disclosed therein. Both corrosion and
abrasive wear naturally tend to reduce the operational life and
reliability of any type of switch, and particularly a rotatable
selector switch.
In addition, the thumb selector switch described in the above
referenced patent included a floating indicator wheel which
required the construction of a switch housing having an internal
bearing or supporting surface surrounding the outside of the
floating indicator wheel. Since the incorporation of this bearing
surface into the switch housing complicates the structure of the
switch housing, and therefore increases the cost of producing the
switch housing, it has been found desirable to simplify the switch
housing, and to eliminate this bearing surface.
SUMMARY OF THE INVENTION
Accordingly, one object of this invention is to provide a novel
thumb actuated selector switch structure.
Another object of this invention is to provide a unique thumb
selector switch structure having a sealed contact assembly.
Yet another object of this invention is to provide a novel sealed
selector switch structure having a simplified switch housing.
A still further object of this invention is to provide a novel
thumb selector switch structure having a rotatable contact carrying
indicia wheel sealed to a printed circuit device.
Briefly, these and other objects of the invention are achieved by
providing a printed circuit board panel having an angularly encoded
conductive pattern printed thereon. A contact carrying indicia
wheel is sealed by means of a plastic casing to the printed circuit
board assembly. A thumb actuatable wheel is coupled to the sealed
indicia and contact carrying wheel to provide actuation thereof.
The entire assembly is mounted within a protective housing having a
detent spring mounted therein.
DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and many of the
attendent advantages thereof will be readily obtained as the same
becomes better understood by reference to the following detailed
description when considered in connection with the accompanying
drawings, wherein:
FIG. 1 is a perspective view of a plurality of thumb switches in
accordance with the present invention mounted together to form a
switch bank;
FIG. 2 is an exploded view of the components of a thumb wheel
switch assembly in accordance with the present invention;
FIG. 3 is a section view taken along the line 3--3 of FIG. 1,
further illustrating the sealed contact assembly of the present
invention; and
FIG. 4 is a plan illustration of the printed circuit board
illustrated in FIGS. 2 and 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, wherein like reference numerals
designate identical or corresponding parts throughout the several
views, and more particularly to FIG. 1 thereof, a ten digit switch
bank 10 is illustrated. The switch bank 10 is comprised of a
plurality of sealed thumb selector switches 12 mounted together.
Each sealed thumb selector switch 12 includes a switch housing 14,
which is preferably constructed of a suitable plastic material.
Referring now to FIG. 2, the structure of the switch housing 14 is
illustrated in greater detail. The housing 14 includes a curved
front panel 16 having an aperture 18 therein. The aperture 18
includes two portions, a generally square indicia viewing opening
20, and an elongated thumb wheel opening 22. A pair of panel
mounting flanges 24 are molded integral with, and are positioned at
opposite ends of, the curved front panel 16. The panel mounting
flanges 24 are useful in positioning the thumb selector switches 12
in electronic panel boards, for example.
A positioning peg 26 and a positioning aperture 28 are formed on a
side surface 30 of the curved front panel 16. The positioning peg
26 and the positioning aperture 28 are used in mounting separate
sealed thumb selector switches 12 together, to form a switch bank
as illustrated in FIG. 1. The location of the positioning peg and
positioning aperture is alternated on opposite sides of each switch
housing 14 so that the individual housings may be readily coupled
together.
In addition to the curved front panel 16, the switch housing 14
also includes a top panel 32, a bottom panel 34, a rear surface 36
and one side panel 38. A spring securing stud 40 is mounted to the
side panel 38 at a position to the rear of the switch housing 14,
and near the bottom panel 34. A detent spring 42 having a detent
portion 44, not shown, is interference fitted about the spring
securing stud 40. A shallow cylindrical indentation 46 may be
provided in the side panel 38 of the switch housing 14, if so
desired, to interfit with a slight protrusion 39 on a thumb wheel.
However, the shallow indentation 46 may be omitted, if desired.
Accordingly, it will be apparent that, except for the spring
securing stud 40, the interior of the switch housing 14 is
substantially devoid of structural members, rendering it
particularly simple and inexpensive to mass produce.
A mounting aperture 48 is provided in a protruding portion 50 of
the rear surface 46 in order to facilitate assembly of the
completed sealed thumb selector switch structure 12, as will be
described hereinafter. In addition, the width of the rear surface
36 is slightly less than that of the front, top and bottom panels,
16, 32 and 34 respectively, providing a positioning ridge 52 which
extends across the rear area of the switch housing 14. The
positioning ridge 52 is extended along the interior surfaces of the
top and bottom panels 32 and 34 to form a peripheral surface
against which the remaining portions of the selector switch
assembly can be mounted.
A sealed indicia wheel and contact assembly 54 is also illustrated
in FIG. 2. This assembly includes a panel 56 of conventional
printed circuit board material, on which an appropriately
configured layer 58, not shown, of conductive material is
positioned. A contact carrying indicia wheel 60 is secured to the
panel of printed circuit board material 56 by means of a clear
plastic encapsulating material 62. A D-shaped axle 64 is secured to
the contact carrying indicia wheel 60, for rotating it. The
D-shaped axle 64 extends through the clear plastic encapsulating
material 62 to permit a thumb wheel 66 to be coupled to the contact
carrying indicia wheel 60. The thumb wheel 66 includes a D-shaped
aperture 68 at the center thereof for receiving the D-shaped axle
64. The thumb wheel 66 includes a scalloped outer surface including
a plurality of evenly spaced projections 70 separated by grooves
72. The projections 70, are, of course, adapted to permit easy
manual rotation of the thumb wheel 76. The grooves 72 cooperate
with the detent portion 44 of the detent spring 42 to restrain the
thumb wheel 66 and the attached contact carrying indicia wheel 60
in positions associated with particular digital outputs. The thumb
wheel 66 may be provided with a short cylindrical projection 39
adapted to interfit with the shallow cylindrical indentation 46 in
the side panel 38 of the switch housing 14, if so desired.
The contact carrying indicia wheel 60 is shown in greater detail in
FIG. 4. The wheel 60 preferably includes a hollow, cylindrical
member 74 having numerical indicia 76 printed on an outer
circumferential surface thereof. The hollow cylinder 74 is
preferably constructed of a conventional plastic material. A metal
contact 78 having a plurality of contact fingers 80 is mounted to
the base of the hollow cylinder 74.
The contact carrying indicia wheel 60 is sealed to the printed
circuit board material 54 by the clear plastic encapsulating
material 62. The clear plastic encapsulating material 62 is
preferably clear polycarbonate plastic, and is formed in the shape
of a flat panel 82, having a cavity in the form of a raised hollow
cylindrical portion 84 therein. The hollow cylindrical portion 84
is formed such that its interior dimensions correspond to the
exterior dimensions of the contact carrying indicia wheel 60. Thus,
in assembling the sealed thumb selector switch 12 of the present
invention, the contact carrying indicia wheel 60 is inserted into
the hollow cylindrical portion 84 for rotation therein. An aperture
86 is formed in the center of the hollow cylindrical portion 84 to
permit the D-shaped axle 64 of the contact carrying indicia wheel
60 to project therethrough. A shallow cylindrical well 88 is formed
in the outer surface of the hollow cylindrical portion 84
concentric with the aperture 86. An O-ring 90, formed of a suitable
flexible sealing material, is inserted into the shallow cylindrical
well 88 so that it surrounds the D-shaped axle 64, and seals the
aperture 86 through which the axle 64 projects.
In order to seal the clear plastic encapsulating material 62 to the
printed circuit board panel 56, a gasket 92 of a suitable bonding
material is preferably used. As shown in FIG. 3, the gasket 92 may
be placed on the printed circuit panel 56 substantially around the
pattern of conductive material 58. The gasket 92 is preferably
formed of B-stage epoxy impregnated into glass cloth, for example.
This material is commercially available from New England Laminatec
Company, Incorporated located at 481 Canel Street, Stamford,
Connecticut. The commercial designation for the material is NELCO
type 10-3205-8.
The particular pattern of the conductive material 58 may be any one
of a number of suitable patterns. The pattern illustrated in FIG. 4
is substantially the same as the coded pattern disclosed in U.S.
Pat. No. 3,665,127, mentioned above.
In assembling the sealed thumb selector switch 12 of the present
invention, the contact carrying indicia wheel 60 is first
preferably inserted into a reset portion provided by the hollow
cylindrical portion 84 in the clear plastic encapsulating material,
and the D-shaped axle 64 is inserted through the aperture 86. The
gasket 92 is then suitably implaced, and the clear plastic
encapsulating material 62 is then positioned over the gasket, and
the clear plastic encapsulating material is thereby sealed to the
printed circuit panel 56 to provide a cover over the printed
circuit panel, the contact carrying indicia wheel and the metal
contact 78 having the plurality of contact fingers 80. The O-ring
90 is subsequently inserted into the shallow cylindrical well 88 to
seal the aperture 86 surrounding the axle 64. The D-shaped axle 64
may then be inserted through the D-shaped aperture 68 in the thumb
wheel 66. When this is done, a short cylindrical projection 94 on
the thumb wheel 66 interfits with the shallow cylindrical well 88,
and applies pressure to the O-ring 90, fully sealing around the
shaft 64 in the aperture 86. In addition, a cylindrical ledge 96
formed on the thumb wheel 66 surrounds the periphery of the
encapsulated contact carrying indicia wheel 60, acting as a bearing
and supporting surface for the thumb wheel 66. This entire assembly
is then inserted into the switch housing 14 such that the thumb
wheel engages the detent portion 40 of the detent spring 42, and
projects through the thumb wheel opening 22 at the other side
thereof. The indicia 76 of the contact carrying indicia wheel 60
are then clearly visible through the indicia viewing opening 20. In
addition, peripheral edge portions of the sealed indicia wheel and
contact assembly 54 abut the positioning ridge 52 of the switch
housing 14, causing the sealed indicia wheel and contact assembly
to be firmly positioned with respect to the switch housing. In
addition, a mounting aperture 100 in the sealed indicia wheel and
contact assembly 54 then registers with the mounting aperture 48 in
the rear of the switch housing 14. Accordingly, a suitable bolt or
rivet, or other fastening means may be passed through the aligned
mounting apertures 48 and 100 to firmly secure the sealed indicia
wheel and contact assembly to the switch housing 14.
In operation, the portion of the thumb wheel, and particularly the
projections 70 thereof, which protrude through the thumb wheel
opening 22 may be manually engaged to rotate the thumb wheel. As
the thumb wheel rotates, it is caused to jump from one digital
position to the next with the detent spring 42 registering in a
corresponding groove 72, to retain the thumb wheel in its positions
selected. Rotation of the thumb wheel drives the contact carrying
indicia wheel 60 coupled thereto by the D-shaped shaft 64. As the
contact carrying indicia wheel 60 is caused to rotate, the contact
fingers 80 sweep across the conductive pattern 58 on the printed
circuit board 56. Accordingly, various connections are made within
the thumb switch, causing the selective energization of a plurality
of individual output terminals 98. However, as pointed out above,
the entire contact assembly is hermetically sealed, preventing dust
or any type of corrosive atmosphere from entering into the sealed
indicia wheel and contact assembly 54. Thus, the sealed thumb
selector switch 12 of the present invention is completely moisture
and dust proof, and is compatible with the sealed rotary switch
requirements set forth in Military Specification MIL-S-22710C.
Obviously numerous modifications and variations of the present
invention are possible in light of the above teachings. It is
therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described herein.
* * * * *