U.S. patent number 3,790,912 [Application Number 05/293,922] was granted by the patent office on 1974-02-05 for flashlight and switch assembly.
Invention is credited to John D. Murphy.
United States Patent |
3,790,912 |
Murphy |
February 5, 1974 |
FLASHLIGHT AND SWITCH ASSEMBLY
Abstract
An improved flashlight construction which substantially reduces
the possibility of arcing, having a glass enclosed magnetic reed
switch electrically connected to the conductor strips along the
wall of the flashlight case and having the magnet required to close
the contact arms of the reed switch incorporated into a slidably
mounted switch cover, the conductor strips being electrically
connected in a fixed position between the conductor rings at the
ends of the case. In a modified form of the switch assembly, the
magnet is positioned in a preformed case which is mounted on the
outside of the flashlight case so that the movable parts of the
switch are completely separated from the internal parts of the
flashlight. Other modifications of switch covers having magnets
mounted therein which can be locked in either the "On" or "Off"
position by means of magnetizable steel are also shown.
Inventors: |
Murphy; John D. (Bayonne,
NJ) |
Family
ID: |
26905509 |
Appl.
No.: |
05/293,922 |
Filed: |
October 2, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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210791 |
Dec 22, 1971 |
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156661 |
Jun 25, 1971 |
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Current U.S.
Class: |
335/205; 335/207;
362/310; 362/205 |
Current CPC
Class: |
F21V
23/04 (20130101); H01H 36/0006 (20130101); F21V
23/0414 (20130101) |
Current International
Class: |
H01H
36/00 (20060101); F21V 23/04 (20060101); H01h
036/00 () |
Field of
Search: |
;335/205,206,207
;240/10.66 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Envall, Jr.; Roy N.
Attorney, Agent or Firm: Koenig; Gloria K.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application is a division of Ser. No. 210,791 filed Dec. 22,
1971 which is in turn a continuation-in part of Ser. No. 156,661
filed June 25, 1971, now abandoned.
Claims
1. A switch cover assembly for use with a magnetic reed switch
operatively mounted in the external wall of a device
comprising:
a. switch cover formed with a chamber and having a front end, back
end, two side walls, an open bottom and a top face formed with an
opening;
b. a switch button slidably mounted over the opening in the top
face of the switch cover;
c. a magnet having its north and south poles in alignment with the
front and back ends of the switch cover and having its north and
south poles positioned parallel to the longitudinal dimensions of
the contact arms of the reed switch, affixed to the underside of
the switch button for movement therewith within the chamber;
d. two strips of magnetizable steel, one strip of steel being
mounted at each end of the switch cover, parallel to the upper face
of the switch cover, the inner end of each steel strip bent
perpendicular to the strip, the perpendicular faces of the strips
being substantially parallel to the ends of the magnet, the
perpendicular faces of the strips being a predetermined distance
from each other with respect to the magnet, so that when the magnet
is magnetically held at one steel face it will be directly over the
center portion of the reed switch and when the magnet is
magnetically held by the second steel strip it will be held away
from the center portion of the reed switch; and
2. A switch cover assembly for use with a magnetic reed switch
operatively mounted in the external wall of a device
comprising:
a. switch cover formed with a chamber and having a front end, back
end, two side walls, an open bottom and a top face formed with an
opening;
b. a switch button slidably mounted over the opening in the top
face of the switch cover;
c. a switch-controlling magnet having its north and south poles in
alignment with the front and back ends of the switch cover and
having its north and south poles positioned parallel to the
longitudinal dimensions of the contact arms of the reed switch,
affixed to the underside of the switch button for movement
therewith within the chamber;
d. two magnets, one magnet being mounted at each end of the switch
cover in alignment with the switch-controlling magnet, with the
north pole of one magnet facing the south pole of the
switch-controlling magnet and with the south pole of the second
magnet facing the north pole of the switch-controlling magnet, the
magnets being a predetermined distance from each other with respect
to the switch-controlling magnet, so that when the
switch-controlling magnet is magnetically held by one magnet it
will be directly over the center portion of the reed switch and
when the switch-controlling magnet is magnetically held by the
second magnet it will be held away from the center portion of the
reed switch; and
e. means to mount the switch assembly on the external wall of a
device.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an improved flashlight wherein the
switching mechanism comprises a glass enclosed magnetic reed switch
mounted in the case and electrically connected to the conductor
strips between the conductor rings formed at the ends of the case.
The normally open contact arms of the reed switch are closed and
the battery operated circuit is completed by the attraction of a
magnet over the contact arms of the reed switch, the magnet being
encased within a slidably mounted switch cover positioned over the
reed switch. In a modified form of the invention, the magnet is
positioned in a preformed plastic case mounted outside of the case
and completely separated from the flashlight assembly within the
case.
In two other modifications of the switch cover, the attraction of
the magnet to steel strips or auxiliary magnets mounted at the ends
of the switch cover is employed to hold the magnet over or away
from the contact arms of the reed switch.
In all forms of the invention, the contact strips along the
longitudinal dimension of the case are welded to the contact rings
at the ends of the case. The reed switch assembly and fixed contact
strips reduce the possibility of arcing within the flashlight and
greatly increase the safety aspects of the flashlight.
2. Description of the Prior Art
There is a great need in mines, in oil refineries and in other
explosive atmospheres for flashlights with safety features which
reduce the chance of any spark which might cause an explosion.
Flashlights are manufactured, known as "permissible" flashlights,
which have received the approval of the Bureau of Mines,
Underwriters Laboratories, Bureau of Ships and the U.S. Coast Guard
which have safety features such as no exposed metal parts, hermetic
seals, and contact points in the switch sealed with rubber.
Nevertheless, even the most carefully made flashlight has several
contact points within the housing of the flashlight which may arc
and cause an explosion in a flamable atmosphere if any part of the
insulation in the housing is defective. The six contact points
within the ordinary flashlight, whether or not safety approved, are
between the coiled spring and one battery, between the batteries,
at the switch where one resilient conductor strip is moved to
contact another resilient conductor strip working in cooperation
with the switch moved to contact the metal reflector cone holding
the bulb assembly, at the friction socket holding the bulb and at
the point of contact between bulb assembly and the battery.
SUMMARY OF THE INVENTION
It is an object of this invention to provide an improved
construction of a flashlight which eliminates two of the contact
points between pieces of metal which are found in all flashlights
made at the present time and which thereby substantially reduces
the possibility of arcing in the flashlight. The use of a glass
enclosed magnetic read switch whose contact arms are in a normally
opened position, provides a switch wherein any spark which might be
caused upon opening or closing the switch is rendered harmless
because of the glass enclosure; the use of the reed switch also
eliminates the need for movable contact strips along the length of
the flashlight case, thus providing a safer flashlight.
It is another object of the invention to provide a novel switch
means by slidably mounting the magnet required to close the contact
arms of the reed switch within a preformed housing which is affixed
to the case separate from the flashlight assembly within the
case.
It is another object of this invention to provide several
structures of switch covers wherein a magnet is mounted within the
switch cover.
It is another object of this invention to provide an inexpensive,
compact flashlight unit which is easy to manufacture.
It is a further object of this invention to provide a switch
assembly which is adaptable for use with other portable devices,
such as sealed beam lanterns.
These and various other objects and advantages of this invention
will be more fully apparent from a consideration of the following
description, drawings and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal sectional view of the device, showing one
form of switch assembly.
FIG. 2 is a top plan view of a portion of the exterior wall of the
device shown in FIG. 1 with the switch removed.
FIG. 3 is a perspective view of a modified form of switch.
FIG. 4 is a sectional view of the switch on the line 4 -- 4 of FIG.
3.
FIG. 5 is a sectional view of the switch on the line 5 -- 5 of FIG.
4.
FIG. 6 is a view similar to FIG. 5 with the locking pin in a
different position.
FIG. 7 is a view similar to FIGS. 5 and 6 with the magnet assembly,
spring and locking pin removed.
FIG. 8 is a sectional view of a modified form of switch cover.
FIG. 9 is a bottom plan view of the switch cover shown in FIG.
8.
FIG. 10 is a bottom plan view of another modified form of switch
cover.
FIG. 11 is a sectional view of another modified form of switch
cover.
FIG. 12 is a sectional view of the switch on the line 12 -- 12 of
FIG. 11.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now specifically to the drawings, a flashlight
constructed according to my invention is shown generally by the
numeral 10 in FIG. 1. The flashlight is formed with a cylinderical
insulating case 11 having a removable front end 12 formed with an
opening and a removable back end 13. An aperture 14 is formed in
the circumferential wall 15 of the case. The front end 12 and back
end are threadely mounted on to the case 11 by threads 38 formed on
the inner surfaces of ends 12, 13 and the outer surface of the case
11. A lens 16 and rubber gasket 35 are mounted at the front end of
the case, the rubber gasket 35 forming an airtight seal at the
front end of the case. A rubber gasket 36 is also mounted between
back end 13 of the case and the body 11 of the case to form an
airtight seal.
The case serves to house a reflector cone 17 of conducting
material, a bulb 18, two D-batteries 19, 20 and a compression
spring 21 of conducting material; the bulb 18 being in electrical
contact with the metal end of one of the batteries 19. Two rings of
conducting material 22, 23 are formed along the inner walls at the
front and back of the case respectively, and a metal contact strip
37 is formed at the back end 13 of the case, one metal ring 23 and
the metal contact strip 37 at the back end of the housing being in
contact with the compression spring 21 and the second metal ring 22
being in contact with the reflector 17, the spring 21 urging the
batteries, reflector, bulb and conducting rings into touching
relationship.
The details of construction and placement to form a partial circuit
between the reflector, bulb, batteries, spring and metal rings are
well understood and further description is not believed
necessary.
A commercially available glass enclosed magnetic reed switch 24 of
the spring leaf type having two contact arms 25, 26 in a normally
open position is mounted in the aperture 14 of the case 11. The
reed switch has a front end 41, back end 42 and center portion 43.
Two strips of conducting material 27, 28 are fixedly mounted along
the longitudinal dimension of the inner wall of the case in
alignment with the ends of the reed switch 24. One conducting strip
27 is electrically connected between the conducting ring 22 at the
front of the case and the front end of the reed switch 41 and the
second conducting strip 28 is electrically connected between the
conducting ring 23 at the back of the case and the back end 42 of
the reed switch.
The closing of the contact arms 25, 26 of the reed switch 24 is
controlled by the attraction of a magnet 29. When a magnet having
its north and south poles parallel to the longitudinal dimension of
the contact arms 25, 26 is placed adjacent to the center portion 43
of the reed switch 24, the normally separated contact arms 25, 26
are brought together by the attraction of the magnet 29 and the
circuit is closed. When the magnet 29 is moved from the center
portion 43 of the reed switch the contact arms 25, 26 separate and
the circuit is opened.
As shown in FIGS. 1 and 2, a switch cover 30 formed with a chamber
39 is slidably mounted in a track 31 formed on the circumferential
wall 15 of the case, on each side of the aperture 14 in which the
reed switch 24 is mounted. The magnet 29 is mounted within the
chamber 39 of the switch cover 30, over the reed switch, with the
north and south poles of the magnet 29 parallel to the longitudinal
dimension of the contact arms 25, 26 of the reed switch. The magnet
may be tied, bolted or held adhesively to a nonconducting block 32
for mounting within the switch cover. Stops 33, 34 or a ridge are
formed on the ends of the track 31 to limit the movement of the
switch cover 30. The switch cover and magnet are positioned so that
when the switch cover 30 is moved forward toward the front end 12
of the case the magnet 29 is directly over the center portion 43 of
the reed switch 24 and the contact arms 25, 26 close to complete
the circuit. When the cover is moved toward the back end of the
case 13 the magnet 29 is moved away from the center portion of the
reed switch 24 and the contact arms open to break the circuit, the
stops 33, 34 limiting the forward and backward movement of the
switch cover 30.
Two modified forms of switch covers to hold the magnet 29 are shown
in FIGS. 8, 9 and 10. As shown in FIGS. 8 and 9, a switch cover,
indicated generally by the numeral 70, is formed as a hollow
rectangular housing having a chamber 71 and having a top face 73, a
front end 81, a back end 82, two side walls 83, 84 and an open
bottom 85 which is adapted to cover a magnetic reed switch 24 which
is mounted in a flashlight case 15 or other device. An opening 72
is formed in the top face 73 of the housing over which a switch
button 74 is slidably mounted. A magnet 29 having its north and
south poles in alignment with the front end 81 and back end 82 of
the switch cover is fixedly mounted on the underside of the switch
button 72 for movement therewith. The magnet 29 is positioned over
a reed switch 24 with its north and south poles parallel to the
longitudinal dimensions of the contact arms 25, 26 of the reed
switch 24 to cause the reed switch to operate as heretofore
described. Two strips of steel 75, 76 are mounted at the ends 81,
82 of the switch cover, parallel to the top face 73 of the switch
cover with the inner or unattached ends of each strip, 75a and 76a,
formed or bent upward at right angles, perpendicular to the strip
so that the perpendicular faces are substantially parallel to the
end faces of the magnet 29. When the magnet 29 is manually moved by
the switch button 74 to either end of the switch cover chamber 71,
it is magnetically attracted to a perpendicular face 75a, 76a of a
steel strip 75, 76 and is held in position until the switch button
74 is again moved manually. The perpendicular faces 75a, 76a of the
magnetizable strips 75, 76 are positioned a predetermined distance
from each other with respect to the magnet 29 so that when the
magnet is magnetically held at one steel face 75a it will be
directly over the center portion 43 of the reed switch 24 and the
contact arms 25, 26 of the reed switch 24 will close. When the
magnet 29 is magnetically held at the second steel face 76a it will
be held away from the center portion 43 of the reed switch 24, and
the contact arms 25, 26 of the reed switch will open. The switch
cover assembly is mounted over a reed switch 24 in a flashlight or
other device by fastening means 77, such as screws, pins or
studs.
A modified form of the aforesaid switch cover is shown in FIG. 10.
In this form of the invention, two magnets 78 and 79 are fixedly
mounted at the ends 81, 82 of the chamber 71 of the switch cover
with the north pole of one magnet facing the south pole of the
switch-controlling magnet 29 and the south pole of the second
magnet facing the north pole of the switch-controlling magnet 29.
As previously described with respect to the steel strips 75, 76,
the magnets 78, 79 are positioned a predetermined distance from
each other with respect to the switch-controlling magnet 29, so
that when the switch-controlling magnet 29 is magnetically held by
one magnet 78 it will be directly over the center portion 43 of the
reed switch 24 and the contact arms 25, 26 of the reed switch will
close. When the switch-controlling magnet 29 is held by the second
magnet 79 it will be held away from the center portion 43 of the
reed switch 24, and the contact arms 25, 26 will open.
It can be seen that the aforesaid arrangements provide switch
assemblies which lock the switch in either the "On" or "Off"
positions and which are responsive to gently finger pressure to
change the position.
A modified form of switch assembly indicated generally by the
numeral 40 is shown in FIGS. 3 through 7, where like parts are
identified by the same numerals as in FIGS. 1 and 2. A base 44 of
non-conductive material preferably rectangular in shape, is formed
with a front wall 45, a back wall 46, and a channel 47 extending
axially of the base between the front and back walls 45, 46. A
switch button 48 is slidably mounted within the channel 47. As
shown in FIG. 4, the button 48 is slidably mounted on a rod 51
mounted between the front and back walls 45, 46. The button 48 may
be formed with a projection 50 along its lower surface, which
projection is formed with a slot for holding the magnet 29.
However, other means of mounting the magnet onto the underside of
the button may be used. As heretofore described, the magnet 29 is
positioned with its north and south poles parallel to the
longitudinal dimensions of the contact arms 25, 26 of a magnetic
reed switch 24 mounted in aperture 14 along a circumferential wall
15 of a flashlight case.
The switch assembly 40 is affixed to the wall 15 of the flashlight
case, over the magnetic reed switch 24 by fastening means 52, such
as pins or studs. The base 44 is affixed to the flashlight case so
that when the switch button 48 is pushed to the front end of the
base, the magnet 29 is positioned directly over the reed switch 24
and the contact arms 25, 26 will close to complete the circuit.
When the button is pushed to the back end 46 of the base the magnet
is shifted away from the center portion 43 the reed switch and the
contact arms 25, 26 open to break the circuit. The attractive force
of the magnet is effective to close the contact arms of the reed
switch despite the presence of the plastic base 44 of the switch
between the magnet 29 and the reed switch 24.
To increase the safety aspects of the flashlight, the switch may
contain resilient means, such as a compression spring 53 positioned
around the guide rod 51, between the front wall 45 of the base and
the front surface 49 of the switch button 48, the guide rod 51
retaining the compression spring 53 and switch button 48 in
alignment. The compression spring 53 urges the switch button 48
toward the back wall 46 of the base, thereby urging the magnet 29
away from the center portion 43 of the reed switch 24. In the event
that a person using the flashlight inadvertently dropped it, the
forward finger pressure on the switch button would be removed, the
switch button 48 with magnet 29 attached would be urged away from
the center portion 43 of the reed switch 29 and the flashlight
circuit would open. However, even in flammable situations it is
sometimes necessary for a person to have the flashlight on while
his hands are free to do some work. Therefore, I have provided a
locking means such as non-magnetizable S-shaped pin 54 for holding
the switch button in the forward or on-position when required. To
support the locking means 54, an aperture 55 is formed through one
side 56 of the base, proximate to the back wall 46 and opening into
the channel 47; a hole 58 is formed through the center portion of
the back wall 46 and an aperture 59 is formed in the back wall 46,
rearward from the hole 58, the aperture 59 extending part way
through said back wall 46, the apertures 55 and 59 being on
opposite sides of the case. An S-shaped pin 54 is movably mounted
transversely of the channel 47, through the hole 58 and apertures
55 and 59, one arm 60 of the S-pin 54 passing through the aperture
55, the second arm 61 of the S-pin 54 passing into the aperture 59,
and the body of the S-pin 54 passing through the hole 58. In
ordinary operation the arm 60 of the S-pin is positioned within the
side wall 56 of base and does not extend into the channel 47 as
shown in FIG. 5. The switch button 48 can then move forward and
backward in the channel, with the spring 53 urging the switch
button toward the back wall 46. When it is desired to lock the
switch in the on-position, the switch button 48 is pushed toward
the front wall 45, the arm 60 of the S-pin is pushed into the
channel 47, blocking the backward movement of the switch button and
thereby locking the magnet in position over the contact arms 25, 26
of the reed switch 24. The movement of the arm 60 into the channel
47 forces the arm 61 to extend out of the aperture 59 at the other
side 57 of the back wall. To release the switch button, the arm 61
is pressed into the aperture 59 thereby moving arm 60 out of the
channel. The switch assembly described provides a unit in which all
moving parts are completely separated from the electrical circuitry
within the flashlight. It is obvious that the switch assembly may
be used on any device containing a magnetic reed switch operatively
mounted in an external wall of the device.
Another modified form of switch cover to hold a magnet 29 is shown
in FIGS. 11 and 12. A switch cover, indicated generally by the
numeral 80, is formed as a hollow rectangular housing having a
chamber 71 and having a top face 73, a front end 81, a back end 82,
two side walls 83, 84 and an open bottom 85 which is adapted to
cover a magnetic reed switch 24 which is mounted in a flashlight
case 15 as heretofore described. An opening 72 is formed in the top
face 73 of housing over which a switch button 74 is slidably
mounted. A magnet 29 is fixedly mounted on the underside of the
switch button 74 for movement therewith within the chamber 71.
Resilient means such as a compression spring 53 are positioned
within the chamber 71 between the front end 81 of the switch cover
and one end of the magnet 29, the compression spring 53 urging the
magnet toward the back end 82 of the switch cover. The switch cover
is affixed to the wall 15 of the flashlight case, over the magnetic
reed switch 24 by fastening means 77 such as screws, pins or studs.
The switch cover 80 is affixed to the flashlight case so that when
the switch button is pushed toward the front end 81 of the switch
cover, the magnet 29 is positioned directly over the reed switch 24
and the contact arms 25, 26 will close to complete the circuit.
Locking means such as a steel S-shaped pin 90 are provided for
holding the magnet in the forward or on-position when the switch
button is pushed forward. To support the locking means, the first
side wall 83 is formed with a pair of apertures, a front aperture
86 and a back aperture 87, both apertures being positioned toward
the back end 82 of the switch cover 80. The second side wall 84 is
also formed with a pair of apertures, a front aperture 88 and a
back aperture 89, both apertures being positioned toward the back
end 82 of the switch cover, slightly rearward of the apertures 86,
87 in the first side wall 86. The S-shaped steel pin 90 is movably
mounted transversely of the chamber 71, the front arm 91 of the
S-pin passing into the aperture 86, the back arm 92 of the S-pin
passing into the aperture 89 and the body of the S-pin passing
through apertures 87 and 88. In the off-position, the front arm 91
is positioned at the edge of the first side wall 86 and the magnet
29 is urged toward the back wall 82 of the switch cover, away from
the reed switch 24. When the switch button is manually moved toward
the front wall 81 of the switch cover the attraction of the magnet
pulls the front arm 91 of the steel S-pin 90 into the chamber 71
behind the magnet thereby locking the magnet into the forward or
on-position directly over the center portion of the reed switch 24.
When it is desired to turn the flashlight to the off-position,
finger pressure on the back arm 92 of the S-pin forces the front
arm 91 out of the chamber 71 and the pressure of the spring 53 on
the magnet 29 forces the magnet away from the center portion of the
reed switch 24 toward the back wall 82 of the switch cover. The
front aperture 86 is formed in the first side wall 83 at a
predetermined distance from the magnetic reed switch 24 with
respect to the size of the magnet 29 so that when the front arm 91
of the S-shaped steel pin 90 is pulled into the chamber 71 by
magnetic attraction it will hold the magnet over the center portion
43 of the reed switch 24 to cause the contact arms 25, 26 to remain
closed until the front arm 91 of the S-shaped steel pin 90 is
forced out of the chamber 71.
It will thus be seen that I have provided a new and improved
flashlight with several modifications of switch assemblies.
Modifications may, of course, be made in the illustrated and
described embodiments without departing from the invention as set
forth in the accompanying claims.
* * * * *