Note: Descriptions are shown in the official language in which they were submitted.
.-.. 2~'C~ 1~1~
4134-pat/tp 1
SWITCH FOR PORTABLE LIGHT SOURCE
BACKGROUND OF TF~E INVENTION
This invention relates generally to portable
light sources and, :pore particularly, to switches for
portable light sources that are actuated through axial
movement of the switch mechanism, or so-called
push-button switches.
Flashlights and other portable light sources
having pushbutton switches for opening and closing the
electrical circuit between the lamp bulb and the
source of electrical energy, typically batteries, are
well-known. The ruggedness and reliability of such
switches is particularly important because, in the
case of most portable light source designs, if the
switch fails it is not otherwise possible to
illuminate the lamp bulb. Switch failure is one of
the more common problems encountered with such
devices. It occurs generally through malfunction of
the mechanical movement of the switch mechanism or
2~ failure of the electrical contacts in the switch to
make proper connection. In addition to being rugged
and reliable, it is desirable that such switches have
a relatively simple and inexpensive design, with
components that are easily assembled to allow
economical manufacture. Many prior pushbutton
switches for portable light sources have not provided
all these attributes.
2~~131~
4134-pat/tp
Another concern of those involved in the
design of portable light sources is preventing
inadvertent operation of the switch to connect the
electrical circuit when not desired. In the design of
hand-held portable light sources, such switches are
typically located in the handle (which in a common
flashlight is its barrel or battery cell tube) so that
the switch may be conveniently operated by the user s
thumb while the handle is grasped in the palm of the
hand. In order to diminish the risk of inadvertent
operation, the switch may be recessed in the handle so
that the pushbutton does not extend significantly
above the handle surface.
In another type of portable light source,
however, the pushbutton switch may be located where it
is either undesirable or impractical to recess it.
Such is the case, for example, with flashlights of the
type having a pushbutton switch located in the tail
cap of the flashlight. With such a flashlight, the
user grasps the barrel in the palm of the hand so the
thumb extends over the end of the barrel to depress
the tail cap switch axially. In this orientation, the
angle of the thumb does not readily permit depression
of a recessed switch with ease. The pushbutton thus
is designed to extend beyond the end of the barrel,
but it is then susceptible to being inadvertently
switched on or off.. There is a need for a switch for
such applications which overcomes this problem and yet
is still easy to operate.
.~ 2~ 01314
4134-pat/tp 3
SUMMARY OF THE INVET1TION
In accordance with the present invention, a
switch assembly for a portable light source is
provided which i.s rugged, reliable, and easily
assembled. The switch is designed to have a multiple
self-wiping action for good electrical contact when
the switch is actuated and uses a contact which is
also self-centering. In a further aspect of the
invention, the switch can be locked in the "off"
configuration to prevent inadvertent switching "on" of
the lamp bulb.
The switch assembly has a push-button which is
axially movable to allow ease of operation and which
is rotatable for locking the switch in the "off"
position. The switch assembly is adapted for use in a
portable light source such as a flashlight which
includes a housing for carrying a power supply, the
power supply having first and second power supply
electrodes. A lamp bulb is supported by the housing
and has first and second lamp contacts, wherein the
first lamp contact electrically couples to the first
power supply electrode. Conductor means are
electrically coupled to the second lamp contact
wherein the power supply, the lamp bulb and the
conductor means are connected in series, when the
power supply is in place, to form an open circuit
having first and second terminals. The switch
assembly includes a switch body securable to the
201310
4134-pat/tp 4
housing. The switch assembly also includes actuator
:neaps axially moveable relative to the switch body for
electrically coupling and uncoupling the first and
second terminals in the housing to thereby switch the
lamp bulb on and off, and rotatably moveable relative
to the switch body for substantially preventing axial
movement of the actuator means and thereby locking the
portable light source in either the on or off state.
In one form of the invention, the actuator
means includes a push-button external to and guided by
the switch body and which is axially movable to turn
the portable light source on and off and rotatably
movable to lock it in either the on or off state
through interaction of the push-button with tangs on
the switch body. This precludes inadvertent turning
on of the portable light source, thereby prolonging
battery life. In a further form of the invention, the
actuator means may include a plunger having
projections or equivalent means for engaging a pocket
or recess after rotation of the plunger in order to
prevent any substantial axial movement of the
plunger. This wauld also serve to lock the portable
1ight source on ar off, thereby providing a second
locking mechanism. The recess may be formed in a
guide sleeve placed in the switch body for guiding the
plunger in its axial and rotational movement. The
projections on the plunger are then guided by the
guide sleeve.
__ 2~~ 131
4134-pat/tp
In a preferred embodiment, the plunger
contacts a rotor having alternating peaks and valleys
for cooperating with peaks on the plunger. The rotor
also includes projections for cooperating with the
projections on the plunger. The rotor follows the
axial movement of 'the plunger and is guided by bearing
surfaces in the guide sleeve. The rotor supports a
preferably four-pronged contact which is insulated by
the guide sleeve from the remainder of the switch body
when the switch is off. The contact can be moved out
of the guide sleeve, against the bias of a
counteracting metal spring contacting a battery, into
electrical contact with a retainer in the switch body
thereby closing an electrical circuit between the
spring and the switch body. In addition to its linear
wiping action, the contact preferably also produces a
wiping action through rotational motion of the contact
as the rotor moves axially and rotationally in the
guide sleeve. The four prongs serve to center the
contact in the switch and provide redundant electrical
contact. Rotation. of the contact during actuation of
the switch causes each of the four prongs in contact
with the retainer to wipe against a different portion
of the retainer surface than during the immediately
preceding actuation of the switch.
Interaction of the plunger, rotor and guide
sleeve during operation of the switch preferably
produces audible clicks so that the user knows when
the switch has been activated sufficiently to hold the
portable light source on or to lock or unlock the
2i~01310
4134-pat/tp
switch. An audible click is produced when the
actuator means is depressed sufficiently to turn the
portable light source on for constant illumination,
after the switch is released to keep it on, when the
actuator means is depressed sufficiently to be able to
turn the portable light source off, and when the
actuator means is returned to its original position to
keep it off. An audible click is also produced when
the actuator means, while the portable light source is
off, is rotated to the locked position or back again
to the unlocked position. However, the switch can be
turned on and he:Ld on with constant pressure on the
actuator means without having the audible click
produced.
Preferably a dual diameter/dual pitch spring
is used to make electrical connection between the
contact and one electrode coupled to the battery. The
larger diameter portion of the coil spring biases the
contact against the rotor and is retained within the
tail cap switch by a bushing and retainer having an
opening only large enough to allow the smaller
diameter portion of the coil spring to extend out of
the switch body for making contact with the battery.
Other features and advantages will become
apparent upon considering the following more detailed
description of the preferred embodiment and the
claims.
._ zaQl~la
4134-pat/tp
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a side elevation and partial cut
away view of a flashlight having a push-button switch
in accordance with a presently preferred embodiment of
the invention;
FIG. 2 is a side elevation view and partial
quarter section of the tail cap and switch shown in
FIG. 1:
FIG. 3 is an exploded perspective view of four
components of the switch of FIG. 2;
FIG. 4 is an end elevation view of a rotor in
the switch of FIGS. 2 and 3;
FIG. 5 is a front elevation view of the
plunger in the switch of FIGS. 2 and 3:
FIG. 6 is a side elevation view of the plunger
of FIG. 5;
FIG. 7 is 3 top plan view of the plunger of
FIG. 5;
FIG. 8 is a side elevation view of a body for
the tail cap and switch of FIGS. 2 and 3;
FIG. 9 is a front elevation view of the
push-button of FIG. 1:
2~C~131~
4134-pat/tp g
FIG. 10 is a side elevation view of a
push-button lock;
FIG. 11 is a perspective view of the
push-button lock of FIG. i0;
FIG. 12 is a side section of the body of
FIG. 8;
FIG. 13 is a front perspective view of a dual
diameter, dual pitch spring used in the switch of
FIG. 1;
FIG. 14 is a front perspective view of a
bushing to be placed on the reduced diameter section
of the coil spring of FIG. 13;
FIG. 15 is a front perspective view of a
retainer for the switch of FIG. 1;
FIG. 16 is a partial side elevation and
partial section view of a portion of the switch
mechanism of FIG. 2 showing the plunger in a locked
position;
FIG. 17 is a partial side elevation and
partial section view of the switch mechanism shown in
FIG. 2 with the plunger in an unlocked position.
FIG. 18 is a partial side elevation and
partial section view of the switch mechanism of FIG. 2
z~ol~~o
4134-pat/tp g
showing the plunger advanced to compress the coil
spring; and
FIG. 19 is a partial side elevation and
partial section view of the switch mechanism of FIG. 2
showing the rotor in a position for maintaining the
flashlight on.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The switch of the present invention is
particularly suited to portable light sources, with
particular application to flashlights, such as the
flashlight 30 shown in FIG. 1. The flashlight
includes a housing in the form of a battery cell tube
or barrel 32 for holding one or more power supply
elements, such as batteries 34. In many flashlights
of well known design, the batteries are oriented in
series and extend substantially from a first end 36 to
a second end 38 of the housing. A lamp bulb 40 is
located at the first end within the flashlight head or
bulb enclosure 42. The bulb is located at the apex of
a reflector 44, as is well known in the art. The bulb
is illuminated by passing current from a positive
terminal 34A to a first lamp terminal for the bulb 40
and through the bulb to a second lamp terminal. In
many flashlights commonly available, the circuit then
continues through the battery cell tube, such as where
the battery cell tube is machined aluminum or some
other conductive material, to a tail cap 46, which is
r.. 20C~ 1310
4134-pat/tp 10
in electrical contact with the negative terminal 34B
of the battery. Depending on the flashlight design
and the type of bulb used, there may be one or more
conductors between the positive terminal 34A of the
battery and the bulb and also between the bulb and the
battery cell tube. Additionally, a conductor other
than the battery cell tube may be used to form a
continuous circuit between the bulb terminal and the
tail cap.
The on/off operation of flashlights is
accomplished in a number of ways, particularly for
hand held flashlights such as that shown in FIG. 1.
The switch for operation of the flashlight can be~
placed on the barrel of the flashlight, in the head or
at the tail cap. In each case, the switch operates by
opening and closing the circuit to the bulb, as is
well known in the art. By placing the switch at the
location of the tail cap, one-handed operation of the
flashlight and operation of the locking feature for
the switch in the present design are made easier.
However, it should be understood that the switch as
described more fully herein provides advantages as a
result of its design apart from its location on the
flashlight, and placement of the switch in the tail
cap is preferred for the additional reasons discussed.
Where the switch is placed at the location of
the tail cap, the barrel and the negative terminal 348
form first and second portions of the circuit which
are separated from each other by the switch in the
2ooi~so
4134-pat/tp 11
tail cap. The switch includes a switch body 56 which
also serves as the tail cap closing the end of the
battery cell tube and holding the batteries within the
barrel. (The terms "tail cap" and "switch body" are
used interchangeably because the tail cap in the
preferred embodiment serves the functions both of a
tail cap and a switch body.) The switch, generally,
also includes an actuator including a push-button 68
(FIG. 2), plunger 120, rotor 130, guide sleeve 140, a
contact 172, a coil spring 72 and bushing 76 and a
retainer 74, the retainer being for retaining the
rotor, contact, coil spring and bushing substantially
within the switch body. In general, the push-button
68, plunger 120, rotor 130 and contact 172 are axially
movable so that the contact, which is electrically
coupled through the coil spring 72 to the negative
terminal 34B of the battery, advances from the
insulated guide sleeve 140 into contact with the
conductive retainer 74 which is electrically coupled
to the metallic switch body 56. This closes the
circuit between the barrel and the batteries, thereby
illuminating the bulb. Subsequent operation of the
actuator returns the contact and the other elements to
their starting positions, thereby opening the
circuit. Rotation of the push-button about the
central axis of the switch body serves to lock the
switch, preventing any substantial axial movement of
the switch, as described more fully below. As used
herein, the terms "lock" and "locking" are to be
interpreted broadly to include the functions of
2~ ~~:~ ~~
4134-pat/tp 12
holding or blocking the flashlight switch in a
particular position.
Considering the external features of the
preferred embodiment of the tail cap/switch in more
detail, the tail cap/switch assembly 46 is threaded
into the second end 38 of the barrel through
threads 48 recessed from the end of the barrel below a
counterbore 50. The circumferential wall of the
counterbore forms a moisture seal through an 0-ring 52
seated in an O-ring groove 54 in the tail cap.
The outer surface of the switch body forms a
cylindrical ring 58 having a diameter substantially
identical to the outer diameter of the barrel 32. The
ring 58 is at the approximate longitudinal center of
the switch body. The ring extends toward the barrel
and terminates at a land 60 for the O-ring groove 54
(FIGS. 2 and 8). The O-ring groove is bounded on the
opposite side by a second land 62. The switch body
includes external threads 64 for engaging the internal
threads 48 formed :in the second end 38 of the barrel,
and the switch body can be threaded into the 38 barrel
so that the second end seats against the edge of
ring 58. Threaded engagement of the switch body and
barrel continues part of the electrical circuit from
the barrel into the switch body.
The remainder of the switch body 56 on the
side of the ring 58 opposite the threads 64 includes a
2~Q~1~1~
4134-pat/tp 13
reduced-diameter cylindrical portion 66 for accepting
and guiding a push-button 68 (FIG. 2), which forms a
part of the axially movable actuator means. The
reduced-diameter cylindrical portion terminates in a
transverse surface from which extend a pair of
diametrically oppositely disposed projections or
tangs 70 having rectangular transverse
cross-sections. T3ls tangs have a larger radial
dimension than tangential dimension and have a
function described more fully below.
Also external to the tail cap 46 is part of a
conductive means in the form of a dual-diameter,
dual-pitch coil spring 72, extendable from the body 56
(FIGS. 1 and 2). The spring makes electrical contact
with an electzode of the battery when the tail cap is
threaded onto tile second end 38 of the barrel 32 and
when the battery 34 is held in the barrel. The spring
also serves to bias the battery or batteries away from
the tail cap and into electrical contact (not shown)
with a contact coupled to the bulb 40. The spring is
held in the end of the switch body by a retainer 74
and is electrically insulated from the retainer and
the switch body by a rubber or a plastic bushing 76.
The bushing includes a ring 78 (FIG. 14) for
encircling the reduced diameter portion of the coil
spring and seating against the larger diameter portion
of the spring. The bushing 76 includes a cylindrical
section 80 extending upwardly from the ring which also
encircles the reduced diameter section of the spring
and extends through an opening 82 in the exposed end
2~~ 1310
4134-pat/tp 14
of the retainer 74 (FIG. 15) so that the spring does
not contact the retainer. The opening 82 is formed in
she end of the retainer which includes wrenching flats
for threading the retainer for engaging internal
threads 86 in a bore 84 of the switch body
(FIG. 12).
The push-button 68 is substantially
cup-shaped, having a cylindrical wall or skirt 90 and
an end 92 closed by a push-button lock 88 (FIGS. 2 and
10) having a disk 94 for covering the end 92. The
skirt is axially slidable over and rotatable about the
cylindrical surface 66 of the switch body 56. The
skirt protects the switch plunger and other internal
parts from damage due to impact side loads against the
push-button. The skirt defines an internal cavity 96
whose depth is almost equivalent to the axial length
of the skirt. A cylindrical wall or second skirt 98
extends from the base of the cavity internally
approximately halfway to the open end of the cavity.
The second skirt is capped off by a cap 100 defining a
rectangular opening 102, the portions of the cap 100
which extend radially inward from the second skirt 98
forming a ledge to be engaged by a portion of a
plunger (described below).
The cavity of the push-button includes a pair
of segments 104 corresponding to the pair of tangs 70
on the switch body. Each segment 104 is complimentary
to the other and, therefore, only one segment will be
described hereafter. The segment is defined by first
20~1~1~
4134-pat/tp 15
and second walls 7_06 and 108, respectively, extending
upwardly coextensive with the second skirt 98.
Neither of the first and second walls are located on a
diameter. The space between the walls define an arc
through which the push-button may rotate, the outer
limits of the arc being defined by contact between the
walls 106 and 108 and the corresponding sides of the
respective tang 70. Preferably, the arc is
approximately 22°. The arc approximates the amount
of rotation accomplished by the push-button and by the
plunger in order t.o lock the tail cap switch, thereby
preventing axial movement of the push-button and
plunger.
The first wall defines a first cavity 110 for
receiving or into which the tang extends, thereby
allowing axial movement of the push-button relative to
the switch body. The first cavity 110 extends to the
bottom of the overall cavity 96. The first cavity is
defined on the other side by a wall 112 forming a
ledge or shelf extending between the wall 112 and the
second wall 108. The shelf 114 is slightly below the
ends of the first and second walls 106 and 108,
respectively. In the unlocked condition, with the
push-button in a first rotational position, the
push-button can move axially relative to the tangs 70
and the switch body, thereby allowing the flashlight
to be turned on ;and off. When the push-button is
rotated such that the end of the respective tang is
opposite, or in alignment, with the shelf 114, the
shelf prevents any substantial axial movement of the
201: 1~
4134-pat/tp 16
push-button. The second wall defines a stop surface
116 against which the tang abuts upon rotation of the
push-button. The interaction of the tangs and the
sectors 104 form a locking mechanism far locking the
switch in the "on" or "off" position. When the switch
is locked in the "off" position, axial movement of the
actuator means i;s prevented. Additionally, as
described more ful:Ly below, rotation of the actuator
means also serves to disengage the plunger lugs from
the rotor lugs thereby resulting in a dual locking
mechanism.
The push-button cap 88 (FIGS. 2, 10 and 11)
closes the end of the push-button. The push-button
cap includes an insert post 118, extending
perpendicularly from the center of disk 94, preferably
having a rectangular transverse cross-section and a
curved end. Two opposing sides (the wider sides)
include a locking ridge extending width-wise across
each side for engaging corresponding notches at the
end of the plunger. Each locking ridge includes a
ramp sloping upward from an approximately middle
portion of the insert post in a direction toward the
disk and terminates in an edge perpendicular to the
side. The push-button lock serves to lock the
push-button and plunger together so that axial
movement of the push-button moves the plunger axially
and rotation of the push-button rotates the plunger.
The internal elements of the switch will now
be described. The push-button engages a preferably
2~f~1~1~
4134-pat/tp 1~
plastic plunger 120 for axially and rotatably moving
the plunger with respect to the switch body 56. The
plunger includes a link body 122 and a cylindrical
plunger body 124 extending on respective sides of an
O-ring 126 encircling the plunger in an 0-ring
groove. The link body 122 links the plunger to the
push-button. The plunger body 124 co-acts with the
guide sleeve 140 while operating on the rotor 130.
The link body includes a pair of oppositely
facing externally rounded sides for passing through a
reduced diameter bore 132 in the switch body (FIGS. 2
and 12). The O-ring 126 engages the cylindrical wall
of the bore for protecting the interior of the switch
body from moisture and other foreign matter and also
for creating a drag force with the bore. The
dimensions of the O-ring and of the rounded sides are
such as to allow both axial and rotational movement of
the plunger within the switch body.
The link body 122 also includes a pair of
oppositely facing flat sides connecting the rounded
sides so that the link body can fit through the
rectangular opening 102 in the push-button. Each
rounded side of the link body 122 includes a groove
134 at the end of a transversely extending ramp 136
extending upwardly between the end of the link body
122 and the groove. The ramps facilitate insertion of
the link body into the rectangular opening in the
push-button. The ramps force the rounded sides of the
link body to move inwardly as the link body is passed
2~01~10
~ 13 4 -pat/ tp 1 g
into the rectangular opening. When the grooves 134
engage corresponding walls in the push-button opening,
the rounded sides of the link body spring outwardly
approximately to their original configuration. The
thickness of the walls forming the rectangular opening
in the push-button are approximately the same as the
width of the grooves 134. This engagement of the link
body with the push-button allows any axial or
rotational motion of the push-button to be translated
to the plunger 120.
The push-button cap 88 engages the link body
in a substantially U-shaped groove 137 in the link
body 122 extending from one flat surface to the
other. The U-shaped opening extends along the same
diameter as that connecting the tangs 70 of the switch
body. The groove substantially conforms to the insert
post 118 on the push-button lock and includes slots
138 for engagement with the respective locking ridges
on the insert post 118. The lead-in surface for the
U-shaped opening is sloped to facilitate insertion of
the insert post 118 and the locking ridges thereon
into the L-shaped opening. In order to accommodate
the locking ridges, the walls of the U-shaped opening
spread slightly until the locking ridges engage the
slots 138. In this configuration, the push-button
cap 88 sandwiches the push-button between the disc 94
and the plunger link body 122. The remainder of the
plunger extends along the bore 132 of the switch body
and into a preferably plastic cylindrical guide sleeve
140.
._ 2t~0 ~l~'~ 1~
4134-pat/tp lg
The guide sleeve 140 (FIGS. 2 and 3) includes
diametrically oppositely facing ribs 142 on the
outside surface for engaging corresponding grooves 144
in the bore 84 o:E the switch body. The guide sleeve
seats down againsr the bottom surface 146 of the bore
of the switch body. The ribs 142 are at the end of
the guide sleeve closest to the batteries. The guide
sleeve has guide surfaces for guiding axial movement
of the plunger and both axial movement and rotational
movement of the rotor 130. The guide sleeve also
provides a lock zone for the plunger such that axial
movement of the plunger is prevented when the plunger
is rotated a certain amount relative to the guide
sleeve. The internal configuration of the guide
sleeve accomplishing these functions will be described
more fully below after consideration of the plunger
and rotor in more detail.
The cylindrical plunger body 124 is
substantially circular in transverse cross-section and
defines a bore 148 into which a cylindrical portion of
the rotor fits so that the rotor can rotate relative
to the plunger. The cylindrical plunger body
terminates in a rim having preferably four
axially-directed points each formed by a pair of
primary cam surfaces 150 oriented preferably 45
degrees to the central axis 151 of the switch and
converging to an apex defining the point. Each point
is oriented diametrically opposed from another and
extends parallel to the central axis of the plunger
body .
2~~ ~~~~
4134-pat/tp 20
Formed on the circumferential face of the
cylindrical plunger body 124 are full lugs 152, one
full lug correspanding to each of the points forming
the primary cam surfaces 150. Each of the full lugs
152 have a pair of secondary cam surfaces 154
co-planar or lush with each of the primary cam
surfaces on the corresponding point. The secondary
cam surfaces are not coextensive with the primary cam
surfaces and terminate at longitudinally extending
guide surfaces 156 for engaging corresponding guide
surfaces in the guide sleeve 140. The lugs extend
only a portion cf the length of the cylindrical
plunger body 124.
The rotor 130, referred to above, engages the
plunger and supports and moves the contact 172. The
rotor includes a cylinder 158 for insertion into the
bore 148 of the plunger and which is long enough to
ensure that it remains inserted during normal
operation of the switch. The rotor also includes
alternating peaks 160 and valleys 162 so that there
are twice as many peaks on the rotor as their are
points on the plunger. The peaks and valleys have
primary bearing surfaces which extend outwardly a
distance equivalent: to the corresponding distance for
the primary cam ;surfaces on the plunger. Therefore,
the peaks and valleys of the rotor engage the primary
cam surfaces 150 on the plunger. The peaks and
valleys on the rotor constitute primary cam
followers. Corresponding to every other peak on the
rotor, the rotor includes half lugs 164, one of which
._. 2Q~ ~3 ~~
4134-pat/tp 21
also corresponds at any given time to a respective
full lug 152 on the plunger. Each half lug includes a
secondary bearing or cam follower surface 166 oriented
preferably at 45° to the central axis of the switch
to follow the mating secondary cam surface on the full
lug of the plunger. The secondary cam follower
surface 166 is coextensive with the primary cam
follower surface on the corresponding peak. However,
each half lug omits the complementary portion or other
half of a full lug in order to facilitate coaction of
the half lugs with the guide surfaces in the guide
sleeve 140. The peaks and valleys and the half lugs
tenainate in a transversely extending contact support
surface 168 which supports the base 170 of the metal
contact 172.
The contact 172 electrically couples the coil
spring to the retainer 74, and therefore the switch
body, to turn the flashlight on. The contact includes
an opening 174 far passing the base of the contact
around a cylindrical contact support 176 on the
rotor. The contact. preferably includes four resilient
leaf portions for increased electrical contact and to
serve a self-centering function. Each leaf portion
has a rectangular transverse cross-section and extends
radially outward from the base of the contact and
axially toward the battery portion of the flashlight.
The end of each leaf curves inward toward the central
axis of the switch so that the square end of each
leaf does not come into contact with the switch body.
Preferably only intermediate portions of each leaf
2~0 ~ 1,31,
4134-pat/tp 22
make contact with any other portion of the switch. It
is also preferred that contact occurs at two points on
~he intermediate portions of each leaf, i.e., at the
side edges. This adds redundancy in the electrical
contact and increases the linear and rotational
self-wiping action.
The coil spring 72 is supported by the base
170 of the contact and provides a forward bias for the
batteries and a backward bias for the rotor and
plunger. The coil spring also provides an electrical
contact between one electrode of the battery and the
contact 172. The coil spring 72 is preferably a dual
diameter, dual pitch coil spring (Fig. 13) with the
larger diameter, larger pitch portion extending
between the contact base and the bushing 76 and the
smaller diameter, smaller pitch portion extending from
the bushing 76 to make contact with the battery. Hy
having the two diameters and pitches, variations in
battery sizes or the number of batteries do not affect
the bias on the :rotor and plunger as much as would
occur with a single diameter, single pitch spring.
The larger diameter portion provides more electrical
contact between the spring and the contact 172, and
provides a ledge against which the ring 78 of bushing
76 can bear to provide the necessary amount of tension
between the bushing and the contact and rotor. The
spring also acts as a buffer for the contact and rotor
whereby differences in compression of the reduced
diameter portion due to different battery sizes does
not significantly affect the amount of compression of
2~~~13~.~
4134-pat/tp 23
the large diameter 'portion between the bushing and the
contact in the rotor. A single diameter spring would
also function adequately if the center of the spring
is fixed relative to the switch body so that
compression by the batteries does not affect the bias
on the rotor and the plunger.
When the flashlight switch is in the "off"
position, part of the plunger and the rotor, all of
the contact and a portion of the coil spring fit into
the guide sleeve :L40. The guide sleeve, when used
with a plunger and rotor having four lugs, has four
sectors, each of which is identical with the other
three. Therefore, only one sector will be described
hereafter. Each sector takes up approximately a 90°
angle and extends axially to each end of the guide
sleeve. Axially, the guide sleeve can be separated
into three zones, a lock zone 180, for locking the
plunger against axial movement, an intermediate rotor
control zone 182, for controlling the axial movement
and rotation of the rotor and, therefore, the contact,
and a contact zone 184, for holding the contact 172
entirely within the plastic guide sleeve thereby
maintaining an open circuit. Each sector includes a
boss 186 defining bearing surfaces for guiding the
lugs on the plunger and rotor. The bearing surfaces
do not affect the primary cam surfaces. A groove 188
extending from the base end of the guide sleeve up to
the contact zone 184 guides the axial movement of the
plunger through the full lugs 152. The lugs on the
plunger can move from the base of the guide sleeve
X0:1310
4134-pat/tp 24
substantially to the contact zone. The lock zone
includes a pocket 190 into which the full lug 152 of
the plunger can be rotated from a first angular
position in the groove 188 to a second angular
position in the pocket 190 whereby the point of the
lug is directly in alignment with a portion of the
boss 186. In this plunger position, the boss prevents
forward axial movement of the plunger.
One side surface on the boss defining the
groove 188 terminates at a backwardly sloping, half
lug bearing surface 191 for guiding a half lug 164 on
the rotor to a recess for the flashlight "on"
position. This position is defined by a valley 192 in
the guide surface. The opposite side of the valley is
defined by an axially directed bearing surface 194
against which the half lug rests when the rotor is in
the "on" position. The bearing surface 194 also
serves to guide the half lug upward upon being pushed
by the plunger. The bearing surface 194 terminates in
a second sloping bearing surface 196 for the "off"
position which guides the half lug back into the next
groove 188. T:he sloped bearing surface 191
corresponding to t:he "on" position is longer than the
sloped bearing surface 196 so that the rotor can
rotate further with respect to the peaks on the
plunger sufficiently to advance the peaks 160 on the
rotor past the respective points on the plunger.
The switch body is preferably formed from a
conductive material such as aluminum. The O-rings are
~0~3~~
4134-pat/tp 25
standard items, a.nd the push-buttons, push-button
lock, plunger, rotor, and guide sleeve are preferably
plastic. The bushing 76 is preferably plastic. The
spring and the contact are metallic as would be known
to those skilled in the art. The materials available
for the remaining portions of the flashlight are well
known to those skilled in the art and selection of
materials will depend on the end use, etc.
Assembly of the switch will now be described.
The guide sleeve 140 is placed in the switch body 56
and the ribs 142 aligned with the corresponding
grooves 144 in the switch body. The ribs on the guide
sleeve provides initial alignment of the plunger with
the tang on the switch body. It also prevents
rotation of the sleeve in the switch body. The
plunger is then inserted into the guide sleeve so that
the full lugs pass along the grooves 188 and so that
the link body 122 passes substantially through the
reduced diameter bore 132 in the switch body. The
link body is inserted into the bore of the push-button
68 such that the arcuate sides of the link body are
pressed inward until the external grooves 134 engage
the sides of rectangular opening 102. The push-button
cap 188 is then inserted into the opposite end of the
push-button so that: the insert post 118 is inserted
into the U-shaped groove in the link body 122. When
the push-button cap is seated, the locking ridges on
the insert post will engage the slots 138 in the
walls of the U-shaped groove. By locking the
push-button to the plunger, the plunger and
~0131(~
4134-pat/tp 26
push-button cannot be disassembled without destroying
one or more of the components. This ensures that one
or more of the parts are not lost upon otherwise
inadvertent disassembly of the switch.
The rotor and contact are then inserted into
the open end of the switch body so that the cylinder
158 of the rotor rests in the bore 148 of the
plunger. The plunger will be oriented in the guide
sleeve such that the full lugs lie in the
corresponding grooves 188. The cylinder 158 is larger
in diameter than the contact support 176 so that the
rotor will not be inadvertently reversed on assembly.
The positioning of the rotor is otherwise immaterial
since the half lugs will either fall in the grooves
188 or the valleys 192. The coil spring can then be
installed on the cylindrical contact support 176 of
the rotor and the. rubber bushing placed over the
reduced diameter portion of the coil spring. The
retainer 74 is then threaded into the end of the
switch body through complimentary internal threads in
the bore of the switch body. The retainer is
dimensioned so that the end adjacent the guide sleeve
abuts the mating end of the guide sleeve and so that
the internal diameter of the guide sleeve is less than
or equal to that of the retainer so that there is an
easy transition fo:r the leaf portions 178 of the
contact when traveling from the contact zone in the
guide sleeve to the internal bore of the retainer.
When the retainer is fully threaded or seated, there
is preferably a gap remaining between the underside of
2l~i~la
4134-pat/tp
the wrenching flats of the retainer and the end of the
switch body. The bushing supports the coil spring
laterally as the tail cap is screwed in. The bushing
also floats with respect to the retainer to the extent
that the bushing extends outside the retainer. When
the spring is depressed by the battery, the bushing
moves slightly with the spring. Upon final assembly,
the switch can be threaded onto the barrel and will
appear as shown in fIG. 1.
With the above-described embodiments, the
flashlight is particularly suited for one-handed
operation. The barrel of the flashlight can be
grasped such that the push-button can be rotated
between the thumb and the forefinger from the locked
to the unlocked position and back again. The
flashlight can be easily turned on by applying
pressure to the push-button by either the thumb or one
of the fingers.
Operation of the switch will now be
described. It will be assumed that there exists a
complete circuit between one electrode of the battery
immediately adjacent the switch and the end of the
barrel into which 'the tail cap is threaded. This may
take any number o:f configurations. Moreover, the
particular form of the electrical connection between
the switch and the battery and between the switch and
the circuit in the barrel can also take any number of
configurations. Considering the disclosed embodiment,
FIGS. 16 and 17 show the switch in the locked and
'~t~~~it~
4134-pat/tp ~g
unlocked configurations, respectively. The flashlight
is off and t:~e contact 172 is housed entirely within
the guide sleeve 140. The plunger and, therefore, the
corresponding °ull lugs 152 are rotated to a second
position shown in FIG. 16 from a first position shown
in FIG. 17. Each point is contained in its
corresponding pocket 190 in the guide sleeve, thereby
preventing axial movement, in the direction right to
left as shown in FIG. 16. In that configuration, it
should be understood that the push-button has also
been rotated to an angular position such that the
tangs on the switch body are directly opposite the
corresponding shelf 114 in the cavity 96 of the
push-button. Further rotation of the push-button and
of the plunger is prevented by the stop surface 116
and the side of the pocket 190, respectively. Also in
this configuration, the primary cam surface 150 on the
plunger is adjacent the corresponding primary cam
follower surface on the rotor 130. (Compare Figs. 16
and 17) Because 'these two surfaces are adjacent one
another, rotation of the plunger back to the position
shown in FIG. 17 is facilitated. Movement of the
point on the half lug over the secondary cam surface
on the full lug is facilitated. Additionally,
movement of the half lug over the point on the full
lug and back down to the position shown in FIG. 17
produces an audible click indicating that the motion
has been completed. An audible click is also produced
upon rotation of the plunger in the opposite direction
for the same reason.
~t3131~
4134-pat/tp 2g
With the configurations shown in FIG. 16 and
17, the rotor is in its lowest point of equilibrium,
the plunger is unextended and the larger diameter
portion of the coal spring is in its most expanded
configuration. Additionally, each of the four leaves
on the contact bear against the inside plastic surface
of the guide sleeve.
In order to turn the flashlight on, the
push-button 68 is depressed, thereby pushing the
plunger axially forward toward the batteries of the
flashlight. The C~-ring 126 on the plunger slides
within the reduced diameter bore 132 in the switch
body. The primary and secondary cam surfaces on the
plunger engage the corresponding primary and secondary
cam follower surfaces on the rotor to push the rotor
against the opposing force of the coil spring. The
rotor is prevented from rotational movement by the
sidewalls of the groove 188. But for the presence of
the sidewalls of the groove, the half lug on the rotor
would slide down toward the rim of the plunger along
the secondary cam surface on the full lug of the
plunger.
As the plunger and rotor advance, the leaves
of the contact move from the end of the guide sleeve
into the bore of the retainer, thereby making
electrical contact with the retainer. This closes the
electrical circuit for the flashlight bulb and
illuminates the bulb. At the transition between the
guide sleeve and the retainer, the half lug of the
2101310 .
4134-pat/tp 30
rotor is still retained between the walls of the
groove 188. Therefore, cahen the flashlight is
unlocked, the flashlight can be turned on with a
minimum of :notion and without any audible click being
produced, as occurs when the half lug rotates after
leaving the confines of the groove 188. If the
push-button is released before the rotor rotates along
the guide sleeve, t:he plunger and rotor will return to
their respective positions shown in FIG. 17. This
allows silent use of the flashlight when necessary
during law enforcement work and the like.
Upon further depression of the push-button,
the tip .of the half lug clears the side edge of the
channel 188. , The spring bias from the coil spring
along with sloped surface of the half lug and of the
bearing surface 191 cause the rotor to rotate to the
position shown in FIG. 18 when the push-button is
fully depressed and the plunger has moved its full
axial extent. The contact also rotates with the rotor
to same extent ha7.f lug moves along the bearing
surface 191. 7:n this configuration of the
push-button, the tangs have reached the bottom of the
cavity 110 in the push-button. The O-ring on the
plunger, however, is still pressed between the O-ring
groove and the reduced diameter bore in the switch
body. An audible click is produced when the valley
162 of the rotor reaches the point of the primary cam
surfaces on the plunger.
When the push-button is released, the bias of
the coil spring forces the rotor, plunger and contact
2a~i31~
4134-pat/tp 31
axially rearward as the point on the half lug slides
along the sloping surface toward the valley 192. The
rotor rotates slightly beyond an angle of 45o from
the groove 188 to the valley 192. The peaks and
valleys intermediate the half lugs do not interfere
with the rotation of the rotor except to the extent
that the primary cam surface 150 on the plunger slides
along the primary cam surface on the peak 160 of the
rotor, because only the follower surface on the half
lug contacts the bearing surfaces on the guide
sleeve. Upon continued rotation of the rotor in
response to the bias of the coil spring, the plunger
is pushed back sufficiently until the half lug comes
to rest in the corresponding valley 192. In this
Position, the peak 160 has rotated beyond the
corresponding point: on the primary cam surfaces of the
plunger. In the configuration shown in FIG. 19, the
contact has rotated slightly more than 45° all the
while achieving a wiping action between the edges of
each portion of the leaf which is in contact with the
surface of the bare in the retainer. The wiping
action is both as a result of the axial movement of
the contact and the. rotational movement of the contact
achieved through rotation of the rotor. This enhances
flow of current while the circuit is closed. While
the contact rotates with the rotation of the rotor, it
does not necessarily rotate an equal amount with the
rotor with every operation of the switch. Rotation of
less than 45° may occur.
In the configuration shown in FIG. 19, the
plunger can be manually retracted sufficiently to
~~t~~o
4134-pat/tp 32
allow it to be rotated back into the pocket 190 in the
guide sleeve. This occurs simultaneously with the
orientation of the push-button with the tang so that
the tang and its corresponding shelf are in
alignment. This in effect locks the flashlight on.
However, the only bias preventing return of the
push-button or plunger to the position shown in FIG.
19 is the friction created between the O-ring 126 and
the bore of the switch body. This may be overcome by
pushing on the push-button after rotation of the
push-buttcn to the unlocked position. The plunger
0-ring 126 contributes a desirable uniform resistance
or drag °orce which smooths out the switch operating
forces. It also keeps the actuator components (i.e.,
the plunger and push-button) in position when the
switch is on and no spring bias is being applied to
them.
In order to return the tail cap switch to the
configuration shown in FIG. 17 the push-button is
depressed, thereby moving the plunger forward against
the rotor. The primary cam surfaces on the plunger
contact the primary cam surfaces on the peaks of the
rotor pushing the rotor against the bias of the coil
spring. As soon as the longitudinal side surface of
the half lug clears the bearing surface 194 in the
guide sleeve, the half lug travels down the bearing
surface 196 and back into the groove 188. The rotor
and contact will then have moved 90 degrees. The
plunger can be rotated as before to relock the
switch.
~2~131~
4134-pat/tp 33
With the flashlight having a switch in the
above-described embodiment, the skirt of the
push-button is guided along the outside of the switch
body. The push-button is substantially prevented from
rocking due to any side impacts against the
push-button. This is due both to the close proximity
of the skirt to the switch body and to the fixed
interconnection between the push-button and the
plunger. Having the skirt extend over the side of the
switch body also allows for easy manipulation for
rotating the push-button between the locked and
unlocked positions. The interaction of the tangs with
the push-button also serves a locking function which
combines with the locking function of the plunger and
the guide sleeve. Preferably, the locking function
through the tail cap is equivalent to the locking
function served by the plunger.
Use of a plunger and rotor and corresponding
cam and following surfaces causes rotation of the
Zp contact and therefore provides a wiping action through
the contact and ,also provides for audible clicks
during action of the switch mechanism. Moreover, by
having the circuit close upon partial advance of the
push-button and plunger, a momentary "on"
configuration for the flashlight can be achieved
without creating an audible click.
Importantly" the plunger and rotor are not in
stable equilibrium when the full lug and half lug are
in alignment except for the fact that they are
~i31(3
4134-pat/tp 34
retained within the groove 188. As a result, as soon
as the half lug is freed from the confinement of the
groove 188, it can rotate freely in response to the
bias of the coil spring.
It should be noted that the above are
preferred configurations, but others are foreseeable.
The described embodiments of the invention are only
considered to be preferred and illustrative of the
invented concept. The scope of the invention is not
to be restricted to such embodiments. Various and
numerous other arrangements may devised by one skilled
in the art without departing from the spirit and scope
of the invention.
