Information
-
Patent Grant
-
6220720
-
Patent Number
6,220,720
-
Date Filed
Friday, July 16, 199925 years ago
-
Date Issued
Tuesday, April 24, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
- O'Shea; Sandra
- Neils; Peggy C
Agents
-
CPC
-
US Classifications
Field of Search
US
- 362 202
- 362 203
- 362 204
- 362 205
-
International Classifications
-
Abstract
A rotatable head flashlight utilizes a bulb carrier having a circuit board on which are mounted contacts which remain in engagement with energy cells in a battery compartment, a bulb-receiving socket, and a switch assembly engageable with, and operated by, a molded shelf on the inner wall of the battery compartment. The switch includes three contacts, one being a movable contact in the form of a resilient, bridge-like element overlying both of the other contacts, the latter two contacts being printed on the circuit board.
Description
SUMMARY OF THE INVENTION
This invention relates to flashlights, and particularly to improvements in water-resistant flashlights.
Conventional flashlights typically incorporate sliding switches in the sidewalls of their battery compartments. Such switches are subject to corrosion and wear, and have been notoriously unreliable. Moreover, because they are subject to leakage, they have been generally unsuitable for use in flashlights intended for underwater use.
These drawbacks of conventional flashlight switches have led to the use of rotatable head flashlights in which the battery compartment has no switch and is entirely water-tight, and in which a head, containing an assembly comprising a bulb, a parabolic reflector and a lens, is threaded onto the battery compartment. In rotatable head flashlights, switching is accomplished by rotation of the head relative to the battery compartment. Rotation of the head on the threads of the battery compartment causes the head to move axially, bringing contacts together, or separating them, depending on the direction of movement of the head. A water-tight seal is maintained between the head and the battery compartment, usually by an O-ring or other suitable sealing device. In some cases one of the contacts is a metal portion of the bulb itself. In others a battery terminal or a part of the battery case is used as one of the contacts. The use of portions of the bulb or portions of a battery or battery case as contacts has the advantage of reducing cost, but sometimes produces unreliable operation. Various other switching devices designed for cost reduction also give rise to a risk of unreliable operation. Still others utilize more complex head assemblies in the interest of reliability.
Reliability is, of course, an especially important consideration in underwater flashlight design, and an important object of this invention is to provide an inexpensive, water-resistant flashlight having a highly reliable switch.
The flashlight in accordance with the invention comprises a battery compartment having first and second opposite ends, and an internal space for containing an electrical energy source having a pair of terminals. The compartment is entirely closed except for a opening at one of the opposite ends, and has threads adjacent the opening. A head assembly, including a lens, has threads engaged with the threads of the battery compartment and provides a fluid-tight closure for the opening of the battery compartment. The operation of the threads moves the head assembly axially relative to the battery compartment as it is rotated. A bulb carrier assembly, supporting miniature incandescent bulb, is receivable through the opening of the battery compartment. The bulb carrier includes a reflector arranged to direct light generated by the light bulb through the lens. The bulb carrier is engageable by the head assembly and movable axially by the head assembly.
The bulb carrier has a pair of electrical terminals engageable with the terminals of the electrical energy source. The bulb carrier also has a normally open switch comprising at least two contacts one of which is movable relative to the bulb carrier. The contacts of the switch are carried by the bulb carrier, and conductors provide a series circuit through the bulb, the switch and the pair of electrical terminals. The battery compartment includes a surface engageable with the movable contact of the normally open switch, and positioned to urge the movable contact in a direction to close the series circuit when the head assembly moves the bulb carrier axially in a first direction relative to the battery compartment.
In a preferred embodiment of the invention, the carrier includes a printed circuit board on which the conductors are printed, and on which both electrical terminals, and the contacts of the switch, are mounted.
The board optionally has a socket mounted on it, removably receiving, and providing electrical connections to, the bulb. In the preferred embodiment, the switch includes three contacts, the movable contact being a resilient, bridge-like element overlying both of the other contacts. The surface engageable with the resilient element is preferably a molded shelf formed on the interior wall of the battery compartment.
Preferably, a spring in the battery compartment urges an electrical energy source in the battery compartment in a direction such that the terminals of the electrical energy source are continuously held in contact with the pair of electrical terminals of the bulb carrier. The electrical energy source preferably comprises a pair of cells disposed in side-by-side relationship and connected electrically in series.
Interengaging elements on the battery compartment and the bulb carrier may be provided to prevent rotation of the bulb carrier with the head assembly while permitting axial movement of the bulb carrier relative to the battery compartment.
Other objects, details and advantages of the invention will be apparent from the following detailed description when read in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a perspective view showing the exterior of a flashlight in accordance with the invention;
FIG. 2
is an exploded view of the flashlight;
FIG. 3
is a partially broken away view of the battery case portion of the flashlight;
FIG. 4
is an plan view showing details of the circuit board on the bulb carrier assembly, including the battery-contacting terminals and the switch;
FIG. 5
is an elevational view of the bulb carrier assembly;
FIG. 6
is a broken-away perspective view showing the bulb carrier assembly in the battery case, and illustrating the operation of the switch; and
FIG. 7
is a sectional view of the bulb carrier taken on plane
7
—
7
in FIG.
4
.
DETAILED DESCRIPTION
As shown in
FIG. 1
, the flashlight in accordance with the invention comprises a battery compartment
10
and a head assembly
12
. The head assembly comprises a lens
14
mounted in a hollow barrel
16
, which preferably has ribs
18
to facilitate manual gripping and rotation of the head assembly relative to the battery compartment. The battery compartment
10
is preferably an injection-molded, unitary element having a blind interior terminating in a closed end
20
having an external tab
22
with a hole
24
, for connection to a lanyard or the like. The battery compartment is preferably designed to hold two cylindrical 1.5 volt “AAA” cells mechanically in parallel relationship to each other, but electrically in series. Oval-shaped indentations are provided on both sides of the battery compartment to facilitate gripping, one such indentation being shown at
26
. The end of the battery compartment adjacent the head assembly is flared at
28
.
The exploded view of
FIG. 2
shows that the battery compartment has an externally threaded extension
30
on the flared part
28
, and that the barrel
16
has internal threads
32
, which are engageable with the threads on extension
30
. The threaded extension
30
is provided with an O-ring
34
, which fits a cylindrical inner wall
36
of barrel
16
.
Because of the cooperation of the threads, rotation of the head assembly relative to the battery compartment causes the head assembly to move axially relative to the battery compartment through a short distance. The cylindrical inner wall
36
of the barrel
16
slides on O-ring
34
, while compressing the O-ring to maintain a water-tight seal.
The flashlight also includes a bulb carrier assembly
38
, which preferably comprises a molded body
40
with a flared end
42
which is engageable with an annular surface
44
inside the head assembly. A printed circuit board
46
is mounted at the opposite end of bulb carrier assembly,
38
. The circuit board carries, on the side visible in
FIG. 2
, a pair of contacts
48
and
50
, and a switch
52
. A bulb-receiving socket (not shown in
FIG. 2
) is mounted on the opposite side of the circuit board. The bulb carrier assembly includes a parabolic reflector (not shown in FIG.
2
), which can be a metallized inside surface of molded body
40
. A slot
54
, extending in the longitudinal direction of the flashlight, is formed on the outer surface of the bulb carrier assembly.
FIG. 3
shows the battery compartment
10
with an electrical energy source consisting of two type “AAA” cells
56
and
58
, arranged mechanically in parallel relationship to each other, and connected electrically in series through a spring
60
inside the battery compartment. The spring consists of a single wire wound into two coils
62
and
64
, connected to each other by an interconnection
66
. The positive terminal
68
of cell
58
and the negative terminal
70
of cell
56
are exposed through the opening
72
in externally threaded extension
30
. The springs not only make the series electrical connection between the cells, but also allow for axial movement of the cells while their series connection between terminals
48
and
50
(
FIG. 2
) is maintained.
As shown in
FIG. 3
, the interior of the battery compartment has formed on it a small, shelf surface
74
, which, as will be seen, is engageable by an element of switch
52
. A molded key
76
extends axially from the location of the shelf surface
74
along the inner wall of extension
30
. This molded key
76
slides in slot
54
and the cooperation of key
76
and slot
54
prevents rotation of the bulb carrier
38
while allowing the bulb carrier to move axially. In a practical flashlight in accordance with the invention, the interior of the battery compartment will have two shelf surfaces directly opposite each other and two molded keys also directly opposite each other. With this construction, the bulb carrier can be inserted in either of two orientations, 180° apart.
FIGS. 4 and 5
illustrate details of the circuit board
46
and switch
52
. Contact
48
, which engages terminal
70
of cell
56
, is connected by conductor
78
to bulb socket terminal
80
. The other bulb socket terminal
82
is connected through conductor
84
(which is on the side of the board opposite to the side shown in
FIG. 4
) to a printed switch contact
86
. Contact
50
is connected to a printed switch contact
88
through conductor
90
.
Switch contacts
86
and
88
are normally disconnected from each other, but can be electrically connected together by a third contact in the form of a resilient spring metal bridge
92
, which is anchored to the circuit board at
94
and
96
. The bridge
92
overlies both contacts
86
and
88
, and has dimples
98
and
100
, which are positioned so that they touch contacts
86
and
88
respectively when bridge
92
is flexed by a force exerted on it by shelf surface
74
(FIG.
3
).
The manner in which the surface
74
approaches the bridge of switch
52
is best shown in FIG.
6
. This figure also shows the key
76
, which extends into slot
54
to prevent the bulb assembly from rotating as the head assembly
12
is rotated.
FIG. 7
shows the bulb carrier
38
, with the two pins of a bulb
102
removably inserted into socket connectors
106
and
108
on the side of the circuit board opposite to the side on which contacts
48
and
50
are located.
In operation, the circuit to the bulb is completed by twisting the head assembly clockwise, causing the bulb carrier to be pushed axially by annular surface
44
toward the blind end
20
of the battery compartment. The springs
62
and
64
allow the energy cells
58
and
56
to move axially as the bulb carrier is pushed, and at the same time maintain contact between energy cell terminal
68
and circuit board contact
50
and between energy cell terminal
70
and circuit board contact
48
. Shelf surface
74
presses on bridge
92
of switch
52
, closing the switch. By virtue of its use of a circuit board-mounted switch, the flashlight of the invention operates with high reliability, there being no use of an element of the bulb itself as a switch contact, and no use of cooperating switch elements mounted respectively on the battery compartment and on the head assembly. The flashlight is simple to manufacture, as all of the electrical switching parts, bulb socket elements and energy cell contacts are circuit-board mounted.
Although the circuit board-mounted switch can consist of one fixed contact and one resilient, movable contact, preferably the switch is a three-contact switch comprising two fixed contacts on the circuit board and an overlying, bridge-like, resilient element arranged to be urged into contact with both of the fixed contacts. The bridge-like element improves the reliability of opening of the switch.
Various modifications can be made to the flashlight described. For example, the battery compartment can be designed to hold a single energy cell, such as a “C” or “D” type cell, in which case one of the energy cell contacts on the circuit board may be centered on the board, and a conductor may be provided in the battery compartment to extend one of the energy cell terminals to a location such that it engages another energy cell contact appropriately positioned on the circuit board. alternatively, the battery compartment can be sized to hold “AA” cells, or elongated so that it can hold more than two cells, for example four “AAA” cells connected in series in a two-by-two arrangement.
Although, in the embodiment described, the bulb is mounted removably in a socket on the circuit board, the pins of the bulb can be instead soldered directly to conductors on the circuit board, in which case the circuit board can be replaced along with the bulb, when the bulb filament burns out. If the circuit board is permanently attached to the reflector, the entire bulb carrier assembly can be replaced.
Still other modifications may be made to the apparatus and method described above without departing from the scope of the invention as defined in the following claims.
Claims
- 1. A flashlight comprising:a battery compartment having first and second opposite ends, and an internal space for containing an electrical energy source having a pair of terminals, the compartment being entirely closed except for a opening at one of the opposite ends, and having threads adjacent the opening; a head assembly comprising a lens, the head assembly having threads engaged with the threads of the battery compartment and providing a fluid-tight closure for the opening of the battery compartment, the head assembly being rotatable on an axis and movable, by the threads as it is rotated, relative to the battery compartment along the axis; a light bulb; and a bulb carrier assembly, supporting the light bulb and receivable through the opening of the battery compartment, the bulb carrier including a reflector arranged to direct light generated by the light bulb through the lens of the head assembly; in which the bulb carrier is engageable by the head assembly and movable thereby along the axis; in which the bulb carrier has a pair of electrical terminals engageable with the terminals of the electrical energy source, a normally open switch comprising at least two contacts, one of which is movable relative to the bulb carrier, and all of which are carried by the bulb carrier, and conductors connected to provide a series circuit through the bulb, the switch and the pair of electrical terminals; and in which the battery compartment has an interior wall and includes a molded shelf formed on the interior wall of the battery compartment, the molded shelf being engageable with the movable contact of the normally open switch and positioned to urge the movable contact in a direction to close the series circuit when the head assembly moves the bulb carrier in a first direction, along the axis, relative to the battery compartment.
- 2. A flashlight according to claim 1, in which the bulb carrier includes a printed circuit board, and in which both terminals of the pair of electrical terminals are located on, and fixed to, the printed circuit board.
- 3. A flashlight according to claim 1, in which the bulb carrier includes a printed circuit board, and in which the contacts of the switch are mounted on the printed circuit board.
- 4. A flashlight according to claim 1, in which the bulb carrier includes a printed circuit board, in which both terminals of the pair of electrical terminals are located on, and fixed to, the printed circuit board, in which the contacts of the switch are mounted on the printed circuit board, and in which said conductors are printed on the printed circuit board.
- 5. A flashlight according to claim 1, in which the bulb carrier includes a printed circuit board, in which both terminals of the pair of electrical terminals are located on, and fixed to, the printed circuit board, in which the contacts of the switch are mounted on the printed circuit board, in which said conductors are printed on the printed circuit board, and including a socket on the printed circuit board removably receiving, and providing electrical connections to, the bulb.
- 6. A flashlight according to claim 1, in which the bulb carrier includes a printed circuit board, in which the contacts of the switch are mounted on the printed circuit board, and in which one of the contacts is a resilient element partly overlying at least one other one of said contacts.
- 7. A flashlight according to claim 1, including a spring in the battery compartment for urging an electrical energy source in the battery compartment in a direction such that the terminals of the electrical energy source are continuously held in contact with the pair of electrical terminals of the bulb carrier.
- 8. A flashlight according to claim 1, including an electrical energy source in the battery compartment, the electrical energy source comprising a pair of cells disposed in side-by-side relationship and connected electrically in series.
- 9. A flashlight according to claim 1, including interengaging elements on the battery compartment and the bulb carrier for preventing rotation of the bulb carrier with the head assembly while permitting axial movement of the bulb carrier relative to the battery compartment.
- 10. A flashlight according to claim 1, in which the bulb carrier includes a printed circuit board having conductors thereon, and in which the bulb is fixed to, and carried by, the circuit board and connected to said conductors thereon.
- 11. A flashlight according to claim 1, in which the bulb carrier includes a printed circuit board, and including a socket on the printed circuit board removably receiving, and providing electrical connections to, the bulb.
- 12. A flashlight according to claim 1, in which the normally open switch comprises two contacts fixed to the bulb carrier, and in which the movable contact is a resilient contact element overlying both of said two contacts and movable by said surface into contact with said two contacts.
- 13. A flashlight according to claim 12, in which said resilient contact element is a bridge-shaped contact element having two ends, and fixed at both ends to the bulb carrier.
- 14. A flashlight according to claim 13, in which the bulb carrier includes a printed circuit board, in which said two contacts are fixed to the printed circuit board, and in which the two ends of the bridge-shaped contact element are also fixed to the circuit board.
- 15. A flashlight according to claim 1, in which the normally open switch comprises two contacts fixed to the bulb carrier, in which one of said two contacts is connected to the bulb and the other of said two contacts is connected to one electrical terminal of the pair of electrical terminals engageable with the terminals of the electrical energy source, and in which the movable contact is a resilient contact element overlying both of said two contacts and movable by said molded shelf into contact with both of said two contacts.
- 16. A flashlight according to claim 15, in which said resilient contact element is a bridge-shaped contact element having two ends, and fixed at both ends to the bulb carrier.
- 17. A flashlight according to claim 16, in which the bulb carrier includes a printed circuit board, in which said two contacts are fixed to the printed circuit board, and in which the two ends of the bridge-shaped contact element are also fixed to the circuit board.
US Referenced Citations (7)