U.S. patent number 3,878,344 [Application Number 05/438,881] was granted by the patent office on 1975-04-15 for cam operated switch assembly having split housing, double action wiping resilient contacts and detent structure.
This patent grant is currently assigned to AMP Incorporated. Invention is credited to Joseph Larue Lockard.
United States Patent |
3,878,344 |
Lockard |
April 15, 1975 |
Cam operated switch assembly having split housing, double action
wiping resilient contacts and detent structure
Abstract
A miniature switch having a manually actuated cam in a first
position resiliently biasing a pair of resilient spring contacts to
positions disengaged from each other thereby interrupting
electrical contact therebetween. The contacts are maintained in
their resilient biased condition to prevent chattering of the
contacts. The cam is manually pivoted to a second position in order
to resiliently deflect at least one of said contacts into wiping
engagement with the other contact and thereby provide electrical
contact therebetween. With the cam in its second position, the
contacts are maintained in resiliently biased conditions to prevent
chatter when the contacts are in electrical engagement. Integral
stops are provided on the cam to limit rotation thereof. The cam
geometry provides positive detent action with at least one of the
contacts to provide positive positioning and retention of said cam
at either of said first and second positions.
Inventors: |
Lockard; Joseph Larue
(Harrisburg, PA) |
Assignee: |
AMP Incorporated (Harrisburg,
PA)
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Family
ID: |
27006789 |
Appl.
No.: |
05/438,881 |
Filed: |
February 1, 1974 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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374841 |
Jun 29, 1973 |
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243678 |
Apr 13, 1972 |
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Current U.S.
Class: |
200/6B; 200/241;
200/318; 200/343; 200/6BB; 200/294; 200/303; 200/318.1; 200/559;
74/527; 74/531; 74/567 |
Current CPC
Class: |
H01H
21/50 (20130101); H01H 23/006 (20130101); Y10T
74/20636 (20150115); Y10T 74/2066 (20150115); Y10T
74/2101 (20150115) |
Current International
Class: |
H01H
21/00 (20060101); H01H 23/00 (20060101); H01H
21/50 (20060101); H01h 021/80 (); H01h 001/50 ();
H01h 009/02 () |
Field of
Search: |
;200/6R,6B,6BA,6BB,6C,11DA,17R,153L,153LA,153LB,291,292,298,318-328 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Scott; James R.
Attorney, Agent or Firm: Kita; Gerald K. AMP
Incorporated
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part application of
application Ser. No. 374,841 filed June 29, 1973, and now
abandoned, which is a continuation-in-part of application Ser. No.
243,678 filed Apr. 13, 1972, and is now abandoned.
Claims
What is claimed is:
1. A switch comprising, a housing, a rotary cam carried by said
housing, and first and second resilient spring contacts, said cam
in a first position engaging each of said contacts and resiliently
deflecting each of said contacts to positions disengaged from each
other, each of said resiliently deflected contacts with said cam in
said first position storing spring energy which acts to provide
engagement pressure against said cam and to prevent chattering
engagement of said contacts, said cam being rotatable from said
first position to a second position engaging said first contact and
resiliently deflecting said first contact into electrical
engagement with said second contact to complete an electrical
circuit therebetween, said cam having a projection thereon
displaceable along an arcuate displacement path as said cam is
rotated from said first position to said second position, said
projection being displaceable along said arcuate displacement path
to an intermediate position between said first and said second
positions and into engagement with said first contact and
deflecting said first contact together with said second contact,
with said contacts in engagement with each other, and thereby
causing a first relative sliding engagement between said contacts
to produce a first wiping action to improve the electrical
engagement between said contacts, said projection being
displaceable from said intermediate position to said second
position along said arcuate displacement path allowing said first
and said second contacts to deflect resiliently by resilient spring
action and thereby cause a second relative sliding engagement
between said contacts to produce a second wiping action for
improving the electrical engagement between said contacts, and an
electrical terminal portion provided on each of said contacts for
making an electrical connection externally of said housing.
2. The structure as recited in claim 1, and further including: a
recess provided in said first contact receiving said projection
therein with said projection in said second position along said
arcuate displacement path, thereby latching said projecting in said
recess and retaining said cam in its second position.
3. In a switch, the combination comprising: a housing, first and
second spring contacts in said housing, a rotary cam carried by
said housing and rotatable in a first angular direction and
deflecting said second spring contact in a direction away from said
first spring contact, thereby interrupting electrical contact
between said spring contacts, said cam including a first bearing
surface, said first contact overlying and engaging said first
bearing surface and retaining said rotary cam fixedly in a first
position and preventing rotation of said cam, first stop means on
said cam engageable on said housing with said cam in said first
position, said cam being rotatable in a second angular direction to
a second position, said cam in said second position being
disengaged from said second spring contact and having said first
stop means disengaged from said housing and further having said
first bearing surface disengaged from said first spring contact,
said cam having a second stop means engageable on said housing with
said cam in said second position, said cam including a second
bearing surface engaging at least one of said spring contacts and
deflecting said first and second spring contacts into engagement
with each other to complete an electrical circuit therebetween.
4. The structure as recited in claim 3, wherein said second bearing
surface is of arcuate projecting configuration and said first
spring contact includes an arcuate detent means receiving said
second bearing surface upon rotation of said cam to said second
position.
5. The structure as recited in claim 4, and further including: said
second bearing surface resiliently deflecting said first spring
contact into engagement with said second spring contact and further
resiliently deflecting said first spring contact and said second
spring contact to cause relative sliding engagement between said
first spring contact and said second spring contact to produce a
wiping action and improve the electrical conduction therebetween,
and said first and second spring contacts storing resilient spring
energy in opposition to said deflection by said second bearing
surface thereby resiliently retaining said first spring contact and
said second spring contact into positive engagement in opposition
to said cam to prevent chatter of said contacts when subjected to
vibration or magnetic forces.
6. The structure as recited in claim 4, wherein said second bearing
surface resiliently deflects both said first and second spring
contacts while in mutual contact for storing resilient spring
energy to provide pressure against each other and prevent chatter
of said contacts.
7. The structure as recited in claim 3, wherein said housing
includes a base and a cover, said contacts having portions
protruding from said base, said cover including portions thereof
overlying said contact protruding portions and fixedly retaining
said contact protruding portions on said base, and latching means
connecting said base and said cover.
8. The structure as recited in claim 7, said housing further
including a tool receiving recess means adjacent said latching
means for receiving a prying tool for releasing said latching means
and unlatching said cover from said base.
9. The structure as recited in claim 3, wherein said first bearing
surface engages and at least partially resiliently deflects said
first spring contact, said first contact storing resilient spring
energy acting in opposition to deflection by said bearing surface
whereby said first contact is maintained in pressure against said
first bearing surface to prevent chattering of said first
contact.
10. The structure as recited in claim 3, wherein said first bearing
surface and said second bearing surface are adjacent each other
along the periphery of said cam, said cam upon rotation from said
first position to said second position displacing said second
bearing surface in an arcuate path about the axis of rotation of
said cam with said second bearing surface forcing said contacts to
resiliently deflect first to a relative maximum and then allowing
partial return deflection of said contacts to create a wiping
action between the engaged contacts.
11. In a switch array comprising a plurality of switches in
relatively closely spaced relationship and individually
programmable for either completing or interrupting respective
circuit paths through the switch array, the combination comprising:
a housing of electrical insulation material having a base portion
and a cover, said base portion having a plurality of projections
thereon forming adjacent and generally parallel spaced partitions,
a space between each adjacent pair of partitions receiving a pair
of resilient spring contacts of electrically conducting material
having first portions projecting into the space between adjacent
pair of spaced partitions and having second portions projecting
outwardly of said base, a rotatable cam of insulation material
rotatably mounted in the space between each adjacent pair of spaced
partitions each said rotatable cam having first biasing means
thereon and being capable of rotation on said single shaft to a
first position engaging said biasing means against at least one of
said first portions of corresponding spring contacts to deflect
resiliently at least one of said corresponding spring contacts into
electrical engagement with the other and thereby establish an
electrical circuit path therebetween, each said rotatable cam
having second biasing means thereon and being capable of rotation
to a second position disengaging said first biasing means from said
first portion of at least one of said corresponding spring contacts
and engaging said second biasing means against said first portions
of said corresponding spring contacts to deflect resiliently said
corresponding spring contacts out of engagement with each other,
thereby interrupting the electrical circuit path therebetween, said
cover overlying said second portions of said spring contacts and
retaining said second portions of said spring contacts against said
base and in depending relationship therefrom to provide depending
electrical leads, each said rotatable cam having portions thereof
protruding from said cover for receiving thereon externally applied
forces required for rotating said cam, each said partition being
relatively closely spaced with each said rotatable cam and
corresponding spring contacts being of relatively low profile
permitting miniaturization of said switch array.
12. The sturcture as recited in claim 11 and further including: a
first shoulder on each said rotatable cam engageable with said
housing upon rotation of said cam to said first position, at least
one of said corresponding spring contacts resiliently biasing said
cam to urge said shoulder against said housing to prevent
inadvertent movement of said cam from said first position, and a
second shoulder on each said rotatable cam engageable on said
housing with said cam in said second position, at least one
corresponding spring contact resiliently biasing said cam to urge
said second shoulder against said housing to prevent inadvertent
movement of said cam from said second position.
13. The structure as recited in claim 12, wherein said first
biasing means of each cam purposely deflects at least one of said
corresponding spring contacts into sliding engagement with the
other to produce a wiping action between the corresponding
electrical contacts and thereby improve the electrical continuity
of the electrical circuit path established therebetween.
14. The structure as recited in claim 11, wherein, as each cam is
individually rotatable to a corresponding first position, said
first biasing means of each cam initially deflects at least one of
said corresponding spring contacts into engagement with the other,
and further resiliently deflects both of said corresponding spring
contacts with said contacts retained in engagement with each other
to produce relative sliding engagement therebetween and thereby
provide a wiping action which improves the electrical continuity of
the electrical circuit path established therebetween.
15. A switch, comprising:
a housing defined by sidewalls,
a pair of contacts molded into the sidewalls of said housing and
projecting into the interior of said housing,
said housing having a cam thereon connected to said housing by a
resiliently deformable hinge,
said housing having a latching portion thereon connected to said
housing by a resiliently deformable hinge portion,
said contacts protruding into said housing and initially being in
spaced relationship,
said cam being pivotable about its hinge to deflect one of said
contacts into engagement with the other contact and complete an
electrical circuit therebetween,
said cam being latchably engageable with said latching portion to
retain said contacts in engagement with each other.
16. A switch having a base and a removable cover portion,
comprising:
a plurality of electrical contacts mounted on said base portion and
having depending electrical terminal portions providing electrical
terminals externally of said base portion,
said base portion defining an exposed enclosure receiving said
electrical contacts,
feet means on said base portion for elevating said base
portion.
said cover portion having thereon having a plurality of manually
actuable cams for biasing selected electrical contacts into and out
of mutual engagement, and
said cover portion being selectively removable from said base
together with said cams to selectively expose said enclosure and
said electrical contacts received in said enclosure.
17. The structure as recited in claim 16, wherein, said enclosure
communicates with a space beneath said base portion, which space is
defined by elevating said base portion with said feet means.
18. A switch, comprising:
a housing,
at least a pair of contacts mounted on said housing initially in
spaced relationship and having portions projecting from said
housing providing pluggable electrical terminals,
at least one actuator cam mounted in said housing and being
displaceable into engagement with at least one of said contacts
deflecting one of said contacts into engagement with the other of
said contacts,
said actuator cam being further displaceable to an intermediate
position deflecting both said contacts while engaged with each
other to produce a first wiping action to improve the electrical
engagement between said contacts, and
said actuator cam being further displaceable from said intermediate
position to another position permitting return resilient deflection
of said contacts while engaged with each other to produce a second
wiping action to improve the electrical engagement between said
contacts.
19. The structure as recited in claim 18, and further including:
detent means on one of said contacts, said actuator cam being
detented in said detent means when said actuator cam is in said
another position.
20. The structure as recited in claim 18, wherein, said housing
includes at least a pair of partitions, said actuator cam is
rotatably supported between said partitions, and said contacts are
received between said partitions.
Description
This invention relates to a miniature switch having a manually
actuated cam in a first position resiliently biasing a pair of
resilient spring contacts to positions disengaged from each other
thereby interrupting electrical contact therebetween. The contacts
are maintained in their resilient biased condition to prevent
chattering of the contacts. The cam is manually rotatable or
pivoted to a second position in order to resiliently deflect at
least one of said contacts into wiping engagement with the other
contact and thereby provide electrical contact therebetween. With
the cam in its second position, the contacts are maintained in
resiliently biased conditions to prevent chatter when the contacts
are in electrical engagement. Integral stops are provided on the
cam to limit rotation thereof. The cam geometry provides positive
detent action with at least one of the contacts to provide positive
positioning and retention of said cam at either of said first and
second positions. As the cam is rotated about its axis of rotation
or pivoted from its first position to its second position a
projection on the periphery of the cam is displaced along an
arcuate path of displacement. The projection engages one of the
contacts at an intermediate point along the path of displacement
and resiliently biases the contact into positive engagement with
the other contact to complete the electrical circuit therebetween.
The projection remains in engagement with the contact until the
projection is further displaced to an end point of the arcuate
displacement path where the projection is received in a recess of
the contact to provide a positive detent action. Also as the
contacts are in engagement, displacement of the projection along
the arcuate displacement path purposely creates first a maximum
deflection of the engaged contacts followed by a partial return
deflection, thereby producing a wiping action between the engaged
contacts which improves electrical conduction therebetween. The
entire switch assembly has a low profile and is readily adapted for
miniaturization, enabling a plurality of rotary switch assemblies
to be located in a standard dual-in-line package (DIP)
microelectronic component. The resilient spring contacts are
advantageously formed into DIP leads for plugging into a printed
circuit board or a DIP header.
Accordingly it is an object of the present invention to provide a
miniature switch having a manually actuated cam resiliently biasing
a pair of spring contact either into or out of electrical
engagement with each other.
Another object of the present invention is to provide a miniature
switch with a cam for selectively biasing a pair of resilient
spring contacts into electrical engagement with each other, the cam
purposely providing a wiping action between the contacts.
Another object of the present invention is to provide a manually
actuable miniature switch of low profile to enable a plurality of
similar switches to be incorporated into a DIP microelectronic
component, with the contacts of each switch advantageously forming
the electrical leads for the DIP package.
Other objects and many attendant advantages of the present
invention will become apparent upon perusal of the following
detailed description taken in conjunction with the drawings,
wherein:
FIG. 1 is an enlarged perspective of a DIP incorporating a
plurality of miniature rotary switch assemblies according to the
present invention, together with a fragmentary perspective of an
apertured printed circuit board receiving the electrical leads of
the DIP;
FIG. 2 is an enlarged, fragmentary exploded perspective of the
perferred embodiment shown in FIG. 1 and further illustrating the
component parts of an exemplary miniature rotary switch assembly of
the DIP;
FIG. 3 is an enlarged section taken along the line 3--3 of FIG. 1
illustrating an exemplary rotary switch assembly with the resilient
spring contacts thereof biased resiliently to interrupt electrical
contact therebetween;
FIG. 4 is an enlarged section taken along the line 4--4 of FIG. 1
further illustrating the embodiment of FIG. 3 with the rotary cam
in an intermediate position causing a maximum deflection of the
contacts;
FIG. 5 is a section taken along the line 5--5 of FIG. 1
illustrating a positive detent action between the rotary cam and
one of the spring contacts;
FIG. 6 is an enlarged perspective of another preferred embodiment
according to the present invention;
FIGS. 7-9 are each enlarged fragmentary cross-sections taken along
the line 7--7 of FIG. 6 illustrating the modes of operation of the
preferred embodiment of FIG. 6; and
FIG. 10 is an enlarged fragmentary section taken along the lines
10--10 of FIG. 6;
FIG. 11 is a perspective view of a portion of the embodiment
illustrated in FIGS. 6-10;
FIG. 12 is a fragmentary perspective of the embodiment shown in
FIG. 11 mounted on a printed circuit board.
With more particular reference to FIG. 1 of the drawings, there is
shown in FIG. 1 generally at 1 a DIP incorporating a plurality of
rotary switch assemblies according to the present invention. As
shown in FIG. 1 taken in conjunction with FIG. 2, the DIP includes
a base 2 of electrical insulation material provided thereon with
parallel spaced partitions, two of which are shown at 4. Each of
the partitions has associated therewith corresponding wedge-shaped
latches 6 located along each lateral margin 8 and also 8' of the
base 2. Between each adjacent pair of partitions 4 are assembled a
pair of resilient spring contacts 10 and 12. The spring contacts
are generally of L-shaped configuration and may be stamped and
formed from metal strip. The first contact 10 includes at one end
thereof a recessed arcuate detent portion 14. The other end portion
of the contact is formed into an electrical lead 16. Adjacent the
lead, the contact is provided with a pair of opposed arcuate
recesses 18. When assembled between the pair of partitions 4, the
recesses 18 receive respective arcuate projections 20 on the edge
margin 8 of the base 2. The projections 20 thereby positively
locate the contact 10 in desired position on the base 2, with the
lead 16 depending from the base, and with the detent portion 14
located between the partitions 4. The second contact 12 is
similarly formed with an electrical lead portion 22 and recessed
portions 24 adjacent the lead portion 22. Such recessed portions 24
also receive projecting portions (not shown) on the base margin 8'
which are similar to the projections 20. The second contact 12 is
thereby positively located in position on the base with one end
disposed between the partitions 4 and the lead portion 22 depending
from the base.
With further reference to FIG. 2, the partitions 4 are provided
with aligned notches 26 adapted to receive and support a shaft 28.
A rotary cam of insulation material generally shown at 30 includes
a central bore 32 which freely receives the shaft 28, thereby
allowing the cam 30 to be freely rotatably mounted on the shaft 28.
In assembly, the rotary cam 30 is disposed between the pair of
partitions 4 in overlying relationship with respect to the contacts
10 and 12. To complete the assembly, a recessed cover of insulation
material generally shown at 34 is received over the pair of
partitions 4. Each of the sidewalls 36 are provided with a pair of
wedge-shaped recesses 38. With the cover received over the
partitions 4, the latching portions 6 will be latchably received in
corresponding recesses 38 to latchably secure the cover 34 to the
base 8 in order to cover the assembly of the contacts 10 and 12,
the rotary cam 30 and the shaft 28. In addition, the sidewalls 36
of the cover will retain the depending lead portions 16 and 22 of
the contacts against the edge margins 8 and 8' of the base 2. Thus
each contact will be constrained from motion by the base edge
margins 8 or 8', the projections 20 which are received in the
recesses 18 and 24 of the contacts and the cover plate sidewalls
36. Additionally, the depending leads 16 and 22 will be positively
located in depending relationship from the base 8. This is an
important feature as shown in FIG. 1, wherein the leads 16 and 22
must be maintained in desired alignment for ease in pluggability
into corresponding apertures 40 and 42 provided in a printed
circuit board 44.
With reference to FIG. 2, taken in conjunction with FIGS. 3, 4 and
5, the cover 34 is shown to be provided with a generally
rectangular slot 46 which is partially received over the rotary cam
30. The slot 46 not only properly aligns the cam 30 for free
rotation between the partitions 4, but also allows operator access
to the cam 30 for manual rotary actuation thereof. Adjacent the
slot 46, the cover is provided with a pair of sidewalls 48 which
are adapted to overlie the corresponding partitions 4. More
particularly, each of the sidewalls 48 is defined by a pair of
inverted inclined sidewalls 50 which intersect directly over the
notch portion 26 of a corresponding partition 4. Also, each of the
notch portions 26 is defined by inclined sidewalls. Thus, the shaft
28 is positively centered in the notch portions 26 by virtue of the
inclined sidewalls shape of the notch portion and by the
intersecting inclined surface configurations 50 of the cover plate
partitions 48 which overlie the partitions 4. Thus what has been
described is a miniature rotary switch assembly. The low profile of
the switch assembly permits the partitions 4 to be spaced closely
together enabling a plurality of similar switch assemblies to be
located in adjacent spaced relationship and incorporated into a DIP
as shown at 1 in FIG. 1. The leads 16 and 22 of each assembly are
maintained on center spacings corresponding to the center spacings
normally associated with other microelectronic circuit components,
thus readily illustrating the miniaturization obtainable in the
rotary switch according to the present invention. Each of the
rotary switch assemblies of the DIP is independently operated.
Accordingly, either a plurality of rotary switch assemblies may be
incorporated into a DIP on a common rotary shaft 28, or a single
rotary switch assembly may be fabricated and used by itself alone
as desired.
For further details of the rotary cam 30 as well as details of
operation of the switch, reference will be made to FIGS. 3, 4 and
5. The rotary cam 30 is generally circular in shape as shown in
elevation in the figures. The cam being received in the slot 46
partially protrudes from the cover 34. The cam is provided with a
pair of intersecting recessed planar surfaces 52 and 54 on the
portion of the cam which partially protrudes from the cover 34. The
cam is further provided with a radially outwardly projecting
integral stop portion 58. The outer circumferential surface of the
stop is generally arcuate and terminates in a shoulder 60 at one
end thereof and a generally reduced diameter arcuate knob or
projection 62 at the other end thereof. Immediately adjacent to the
knob 62 the cam circular periphery is provided with an inverted
notched or undercut relieved portion 64. Immediately adjacent to
the undercut portion 64 is provided another projecting arcuate knob
66 provide on the circular periphery of the cam 30. The arcuate
surface of the knob 66 is purposely continuous with the surface of
the undercut portion 64 to form a smooth surface transition
therebetween. In circumferential spaced relationship from the knob
or projection 66, the outer circular periphery of the cam 30 is
provided with another projecting stop 68 provided at one end
thereof with a shoulder 70. In operation, typically the assembly is
mounted on the printed circuit board 44 with the leads 16 and 22
plugged into corresponding printed circuit board apertures 40 and
42. Typically the leads are soldered in place such that they make
electrical contact with printed circuit paths illustrated at 72 and
74. The contacts 10 and 12 have portions overlapping each other.
When the contacts 10 and 12 are in mechanical engagement, a circuit
path is completed between the circuit path 72, through the contact
10, into the contact 12, and through the printed circuit path 74.
As shown in FIG. 3, when it is desired to interrupt the circuit, an
operator manually rotates the cam 30 clockwise by applying pressure
to the planar surface 52 causing the cam to rotate clockwise until
the surface 52 is generally coplanar with the top surface 56 of the
housing 34. With the cam in such a desired position, the projection
62 will engage and resiliently bias or deflect the contact 12
generally counter-clockwise in cantilever fashion. In addition, the
surface 70 of the projecting shoulder stop 68 will stop against the
undersurface of the top wall 56 of the cover 34 to prevent
excessive clockwise rotation of the cam 34 by the operator. Also,
the contact 10 will be at least partially received in and engaged
on the surface of the undercut portion 64. The surface of the
undercut portion will partially resiliently deflect the contact in
cantilever fashion. Accordingly, with the cam in the position as
shown in FIG. 3, the contacts 10 and 12 will be resiliently biased
out of contact with each other to interrupt the described circuit
path. In addition, the cam engages both contacts and resiliently
biases them in cantilever fashion, thereby storing spring energy in
the contacts in opposition to the biasing cam. The stored spring
energy thus insures positive retention of the contacts in desired
position by the cam to prevent chattering of the contacts and
possible contact therebetween when the assembly in subjected to
vibration or magnetic force fields. In addition, the stored spring
energy of the contact 10 forcibly urges the cam in a clockwise
direction, forcing the shoulder 70 to positively stop or seat
against the top wall 56 of the housing 34 thus restraining the cam
from inadvertent rotary movement. As the shoulder 70 is positively
urged into seating relationship by the resilient stored spring
energy of the spring contact 10, a positive detent action is
experienced, indicating to an operator that the cam has been
sufficiently rotated to a position whereby the circuit is
interrupted by virtue of disengaging the contacts 10 and 12 from
each other.
In FIG. 5, the cam is shown rotated counterclockwise from its
position in FIG. 3 to a second desired position whereby the circuit
path is re-established by virtue of contact between the resilient
spring contacts 10 and 12. In operation, an operator manually
applies pressure to the surface 54 rotating the cam until the
surface 54 is generally coplanar with the top wall 56 of the
housing 34. This rotates the knob 62 out of engagement with the
spring contact 12. With the cam in this position, the surface 60 of
the stop 58 becomes positively seated against the undersurface of
the top wall 56 of the cover 34. In addition, the knob 66 is
displaced in an arcuate displacement path about the axis of the
shaft 28. The knob engages the spring contact 10 and forcibly
biases or deflects it resiliently clockwise in cantilever fashion
and in opposition to the stored spring energy therein. The knob 66
also deflects the spring contact 10 into engagement with the
contact 12 to establish the electrical circuit therebetween. Once
contact between the springs 10 and 12 is accomplished, arcuate
displacement of the knob is continued in order to forcibly deflect
both spring contacts 10 and 12 in resilient cantilever fashion. At
the end point of its displacement path, the knob 66 registers in
the recess portion 14 of the contact 10. Since the contact 10 is
resiliently deflected by the knob 66, a positive detent action will
be experienced when the knob registers within the recess portion
14. This indicates to an operator that sufficient counterclockwise
rotation of the cam has been accomplished to complete the
electrical circuit by virtue of electrical contact between the
spring contacts 10 and 12. With the knob 66 in registration within
the recess portion 14, both contacts 10 and 12 will be resiliently
biased by the cam in cantilever fashion. Resilient spring energy
will thus be stored in the contacts 10 and 12 to assure the
application of pressure therebetween which improves electrical
conduction at the point of engagement between the contacts. In
addition, the spring energy retains both contacts positively in
resilient opposition against the cam to prevent chattering of the
contacts when the assembly is subjected to vibration or magnetic
force fields. As a further feature, the resilient stored energy of
the spring contact 10 is transmitted in a direction offset radially
with respect to the shaft 28 tending to urge the cam
counterclockwise to positively seat the shoulder 60 against the top
wall 56 of the housing 34, and prevent inadvertent movement of the
cam from its desired position as shown in FIG. 5. The smooth
surface transition from the undercut portion 64 to the knob 66
assures relatively friction free travel of the cam over the contact
10 which allows smooth rotation of the cam and smooth operation of
the switch.
As a further feature of the invention reference will be made to
FIG. 4. As shown in the figure, the cam 30 is in an intermediate
position during counterclockwise rotation from its position shown
in FIG. 3 to its position shown in FIG. 5. The knob 66 engages the
contact in an intermediate point along its arcuate displacement
path about the axis of the shaft 28. As shown the knob engages and
forcibly deflects the contact 10 into engagement with the contact
12. In addition, both contacts 10 and 12 are deflected to a
relative maximum deflection with the knob 66 in its intermediate
point as shown in FIG. 4. Thus, the knob engages the contact 10 at
an intermediate point along the path of displacement resiliently
biasing the contact into positive engagement with the other contact
to complete the electrical circuit therebetween. The projection
remains in engagement with the contact until the projection is
further displaced along the arcuate displacement path to an end
point where the projection is received in a recess of the contact
to provide a positive detent action. In addition, with the two
contacts in engagement, displacement of the projection along its
arcuate path from its intermediate point to its end point purposely
creates a relative maximum cantilever deflection of each contact in
opposition to their spring energy, followed by a partial return
cantilever deflection of each contact when the knob is received in
the recess portion 14, thereby producing a wiping action between
the engaged contacts which improves electrical conduction
therebetween.
Advantageously, the recess portion 14 forms a protruding line
contact between the contacts 10 and 12. As a further feature,
aperture 76 may be provided in the cam adjacent to each of the
surfaces 52 and 54, such that when a plurality of cams are located
in a DIP, the corresponding apertures 76 of similarly positioned
cams will be in alignment to allow passage therethrough of a wire
which locks the cams from rotation. Of course, when it is desired
to reposition the cams, the wire may be removed from the apertures
to allow individual rotation of the cams over the common shaft 28.
As a modification each recess 38 of the cover may include a flared
relieved portion 39 to permit entry of a prying tool for separating
the cover from the assembly.
FIGS. 6 through 10 illustrate another preferred embodiment
according to the present invention wherein there is shown generally
at 78 a switch having a base portion 80 molded of a dielectric
material into a generally U-shaped channel configuration. The base
portion includes spaced rows of resilient spring contacts 82 which
are stamped and formed from metal strip and are similar to the
contacts 12. More particularly, each contact 82 is generally of
L-shaped configuration and is provided at one end thereof with an
arcuate portion 84, with the other end portion of the contact
formed into an electrical load 86 which projects outwardly through
the sidewall of the base 80 in depending relationship for
connection within apertures of a printed circuit board illustrated
generally at 88. As shown the contacts 82 of one row have their
arcuate portions formed upwardly, whereas the contacts 82 of the
other row have the end portions 84 downwardly and initially in
spaced relationship with the upwardly bent arcuate portions 84 of
the contacts in the one row. The base has a pair of sidewalls 81
into which the contacts 82 are molded. Two sidewalls 83 bridge
across the sidewalls 81, although the sidewalls 83 are of shorter
elevation than the sidewalls 81. Each of the sidewalls have a pair
of integral projecting arcuate feet 85 positioned at each corner of
the base 80.
A cover portion for the base is illustrated generally at 88 and
comprises a singular molded member of dielectric material.
More particularly, the cover portion includes an encircling frame
having integral sidewalls 90, 92, 94 and 96. Each of the sidewalls
94 and 96 straddles across the sidewalls 81 and includes an
integral depending rectangular portion 98 which is inserted between
the sidewalls 81 in the base portion 80. The rectangular sidewall
portions 98 thereby provide partitions at each end of the U-shaped
channel base portion 80, with the contacts 82 contained within the
housing interior formed by the cooperating cover 88 and base
portion 80. The cover 88 is provided with a plurality of adjacent
and spaced cams some of which are shown at 100. Each cam 100 has a
relatively thin web or hinge 102 adjoining the cam integrally with
the sidewall 90. Each cam 100, as shown in FIGS. 7-10, is generally
of inverted elbow-shaped configuration, with one arm portion of the
elbow illustrated at 104 and provided with a first shoulder portion
106 at the terminal end of the outwardly projecting arm portion
104. An inverted shoulder 108 is provided at an opposite end of the
arm portion 104 adjacent to the bend in the elbow shaped portion of
the cam 100. Each cam 100 adjacent to the hinge portion 102 thereof
has a relatively thickened portion 110 which terminates in an
arcuate cam surface 112 which projects internally into the interior
of the housing formed by the cooperating cover portion and base
portion. As shown in FIG. 7, each cam portion 100 has its
relatively narrow resiliently deformable hinge 102 outwardly
flaring into an inverted shoulder 114 which registers in overlying
relationship against a corresponding partition 81 and which is
integrally joined to the sidewall 90.
Also shown in FIGS. 7 through 10, the sidewall 92 is provided with
an elevated projecting portion 116. As shown in FIG. 10, the
sidewall 92 is generally L-shaped with the projecting portion 116
forming an upright leg of the L-shaped portion. A generally
horizontal extending leg 118 of the L-shaped sidewall 92 is
provided thereon with a plurality of projecting latching portions
120 which are adjacent to in spaced relationship from the
projecting wall portion 116. Each latching portion 120 has a
projecting tip defined by a tapered inclined sidewall portion 122
which terminates in an inverted shoulder 124 to define a generally
inverted hook-shaped latching portion. Each latching portion 120
terminates in a relatively reduced thickness resiliently deformable
hinge portion 126 integral with the leg 118 of the sidewall 92.
With reference to FIG. 10, the sidewall 90 and the leg portion 118
are each provided with a plurality of integral depending latching
arms 128 which terminate in inverted wedge-shaped latches or hook
portions 130. Each of the depending portions 128 register within
corresponding grooves 132 provided in the outer surfaces of the
sidewalls 81. The grooves 132 communicate with notch portions 134
provided in the outer surfaces of the sidewalls 81. When the cover
portion 78 is received over the sidewalls 81, the latch portions
130 will register within the notch portions 134. The sidewalls 81
will thereby be compressibly received between the partitions 98 and
the latch portions 128.
In operation reference will be made to FIGS. 7, 8 and 9. Initially,
the cam 100 is illustrated in its relaxed position as shown in FIG.
7 with the arcuate projection 112 thereof in adjacent spaced
relationship with respect to one of the arcuate contact portions
84. The contact portions 84 are in spaced relationship with respect
to each other. When the cam 100 is pivoted about its resiliently
deformable hinge 102, in a clockwise direction as shown in FIGS. 7
and 8, the arcuate projection 112 thereof will initially engage the
contact portion 84 of one of the contacts 82, deflecting the
portion of the contact 82 which projects into the housing interior
in cantilever resilient deflection until it initially engages the
other contact portion 84 of the other contact 82. Such pivotal
displacement of the cam 100 causes the projection 104 thereof to
engage against the latching member 120 adjacent its inverted hook
portion 124. This will cause the latching member 120 to pivot
resiliently about its resiliently deformable hinge 126 in a
clockwise direction as shown in FIG. 8. Although contact between
the projection 104 of the cam 100 and the latch member 120 is not
illustrated, the latching member 120 is illustrated in a greatly
exaggerated deflected position for the purpose of illustrating that
the latching member 120 is capable of pivotal deflection until
engagement against the projecting leg 116 of the sidewall 92 to
prevent excessive deflection and breakage along the resiliently
deformable hinge portion 126. Thus the projecting leg portion 116
provides an antioverstress stop limiting the pivotal motion of the
latching member 120. Accordingly, merely upon manually pivoting the
cam member 100 in a clockwise direction, it will engage the
latching member 120 and cause it also to pivot clockwise, thereby
eliminating the need for purposely pivoting the latching portion
120 by separate operation.
Clockwise pivotal motion of the cam 100 continues until the arcuate
projection or cam surface 112 engages and deflects one of the
contact portions 84 into forceful engagement against the other
contact portion 84. Clockwise pivotal motion of cam 100 is
continued with both of the contact portions 84 in mutual
engagement, thereby causing both contacts 82 to resiliently deflect
in cantilever fashion while their contact portions 84 thereof are
in mutual engagement. Since the contacts 82 are fixedly secured in
their respective sidewalls 81, and since the contact portions 82
undergo cantilever deflection with their contact portions 84 in
engagement, a substantial sliding action occurs between the surface
of the contact portions 84 to provide a wiping action. Such wiping
action provides a scrubbing or cleaning of the surfaces of contact
between the contact portions 84 to improve the electrical
engagement therebetween. The pivotal displacement of the cam 100
continues until the arcuate projecting cam surface 112 registers
within the concave configuration of the contact portion 84 to
provide a positive detent action of the cam geometry with at least
one of the contact portions 84 and to provide positive positioning
and retention of said cam in its position shown in FIG. 9. In
addition, the inverted shoulder 108 of the cam 100 will engage
against the top surface of the sidewall 81 of the base portion of
the housing. Accordingly, the housing provides a positive stop
against which the cam is seated to position and retain the cam in
its position as shown in FIG. 9. The shoulder portion 106 of the
cam 100 will be received under the inverted shoulder or hook
portion 124 of the latching member 120. Since the latching member
120 originally was resiliently deflected in counterclockwise
pivotal-motion, the hinge 126 will cause resilient counterclockwise
pivotal motion of insure that the hook portion 124 is received over
the shoulder portion 106 of the cam 100, again positively
positioning and retaining the cam in its position as shown in FIG.
9. In addition as shown in FIG. 9 the shoulder 106 is retained in
partial compression against the latching member 120 retaining it in
a slightly clockwise displaced position in order to retain some
residual spring energy in the hinge portion 126 and thereby
insuring that the latch portion 124 is resilient biased by the
hinge portion 126 into a latching engagement over the shoulder
portion 106 of the cam 100. The cam 100 in its position shown in
FIG. 9 retains the contacts 82 in partially deflected conditions
with their contact portions 84 is mutual engagement to complete a
circuit path therebetween. The contacts are maintained in their
resilient biased condition to prevent chattering of the contacts
due to vibration.
To release the cam 100 and to interrupt the circuit between the
contact portions 84, the latching member 120 is manually grasped
and forcefully pivoted in clockwise deflection, to its position as
shown in FIG. 8. This removes the hook portion 124 from engagement
on the shoulder portion 106 of the cam 100, permitting the cam 100
to pivot in counterclockwise fashion due to the resilient action of
its resiliently deformable hinge 102. The cam 100 therefore will be
allowed to resiliently pivot and return to its original position as
shown in FIG. 7, thereby allowing the contact portions 84 to
separate and assume their initial positions shown in FIG. 7 and
interrupt the circuit therebetween.
With more particular reference to FIGS. 11 and 12, additional
features of the preferred embodiment illustrated in FIGS. 6-10 will
be explained in detail. FIG. 11 more particularly illustrates the
base portion as having an enlarged interior compartment 136 defined
by the encircling side walls 128 and the end walls 83. As shown the
compartment 136 is completely uncovered and thus fully exposes the
contacts 82 which are mounted in protruding relationship through
the side walls 128 as described. Also as shown in FIG. 11, a
plurality of optional interior partitions 138 may be fabricated
integral with the side walls 128 to divide the interior
compartments 136 into a plurality of smaller compartments 136a,
136b, 136c, and 136d. Each compartment accordingly holds or
separates one corresponding pair of contacts 82 from the other
pairs of contacts. It is however to be understood that the
partitions 138 are optional and that the contacts 82 may be located
in spaced pairs by the sidewalls 128 along without a need for the
partitions 138. The base portion 80 is fabricated as shown in FIG.
11 purposefully to prevent enclosure of the contacts until the
cover portion 88 is assembled to the base portion. The advantage of
such a construction will become apparent by reference to FIGS. 8
and 12. As shown in the figures, the base portion 80 is first
mountable on the printed circuit board 88 with the depending end
portions 86 of the contacts 82 being received in corresponding
apertures of the printed circuit board 88 and being soldered in
place to secure the base portion on a surface of the printed
circuit board at a desired location. The feet portion 85 engage the
surface of the printed circuit board 88 and therefore slightly
space the base portion 80 away from the surface of the printed
circuit board. The end walls 83, the side walls 128, the partitions
138, if provided, and the contacts 82 therefore are spaced from the
surface of the printed circuit board 88. The printed circuit board
88 may then the subjected to a cleaning operation while the base
portion 80 is mounted thereon. Since the base portion is spaced
from the surface of the printed circuit board 88 cleaning and
rinsing chemicals and solutions are allowed to pass freely under
the base portion 80 to thoroughly clean the surface of the printed
circuit board 88 which lies beneath the base portion. Since the
cover portion 88 has not yet been assembled to the base portion 80,
there is no danger that the cleaning and rinsing operation would
result in trapping chemicals or other contaminants within the
enclosure 136 of the base portion. In fact, the exposed contacts 82
also may be cleaned and rinsed during the same operations together
with the surfaces of the printed circuit board 88. Also the exposed
nature of the base portion 80 permits a thorough inspection after
the cleaning and rinsing operations to ensure that no contaminants
are in fact contained within the enclosure 136. Subsequent to the
cleaning and rinsing operations, the cover portion 88 may be
removably assembled to the base portion 80 as previously described.
The resultant structure of the switch embodiment described thus
fulfills a long existing need in the prior art for a switch which
avoids internal contamination. Previously such a switch was in the
form of a completely sealed capsule. It was difficult to fabricate
and seal such a switch because the mating parts were of miniature
size and had to be fabricated with close tolerances. To add to the
difficulty, sealant material in the form of an epoxy, adhesive or
other fluid or semi-fluid substance was utilized to seal all the
seams between mating parts. Due to the miniature size of the parts,
however, the sealant material was difficult to control a would
often migrate to cover the contacts and other operative moving
parts of the switch which were utilized to make and break the
contacts during the required switching operations. The present
invention resulted from a need to eliminate such disadvantages of a
sealed switch. Instead it was discovered advantageous to provide a
completely exposed base portion of the switch which allowed free
passage therethrough of cleaning and rinsing solutions. Thus
instead of attempting to provide a completely sealed switch in
order to avoid entrapment of contaminants, the switch according to
the present invention avoids entrapment of contaminants by
providing a switch interior which is fully exposed for cleaning,
and more particularly for preventing accumulation of contaminants
therein. Thus the switch according to the present invention
fulfills a long existing need for a switch which can be mounted on
a printed circuit board and yet avoid entrapment of contaminants on
the printed circuit board when subjected to cleaning and rinsing
operations. The provision of such a switch allows such cleaning and
rinsing operations to be delayed until all of the contaminant
impervious circuit components are mounted on the printed circuit
board and soldered in place. Since all the components are mounted
to the board before a final cleaning operation, there is no danger
that the board surfaces will be recontaminated by repeated
handling, and yet the components when mounted to the printed
circuit board will be either impervious to the cleaning solutions,
or, in the case of the switch accordingly to the present invention,
will avoid internal contamination by being purposely exposed during
such cleaning and rinsing operations.
Although preferred embodiments of the present invention have been
shown and described in detail, other embodiment and modifications
of the present invention are intended to be covered by the spirit
and scope of the appended claims wherein:
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