GB2211924A

GB2211924A - Electric torch

Info

Publication number: GB2211924A
Application number: GB8725518A
Authority: GB
Inventors: Ho Leung Leslie Chow
Original assignee: ACCURIST
Current assignee: ACCURIST
Priority date: 1987-10-30
Filing date: 1987-10-30
Publication date: 1989-07-12
Also published as: GB8725518D0

Abstract

An electric torch is turned off and on by screwing and unscrewing the head assembly (H) on the body (11), which causes axial movement of a lamp mounting (33), due to a spring (20), to make and break contact between a fixed contact ring (15) and a movable contact (17b) which is part of the lamp mounting (33). Ears (23f) of a molded plastic part (23) of the lamp mounting (33) project forwardly of the fixed contact ring (15) to engage a ring portion (22a) of a reflector (22) in the head assembly (H), to produce the axial movement of the lamp mounting (33). <IMAGE>

Description

Electric Torch This invention relates to an electric torch.

All or nearly all known electric torches are each provided with a manually operable switch to open and close electrical contacts for switching on and off. Not only is such a manually operable switch usually of complicated construction and liable to fail after repeated use, but it is also extremely difficult or impossible to render water-proof if the torch as a whole is required to be water-proof.

United States patent specification no. 4,577,263 (Maglica) discloses an electric torch comprising a barrel (21) forming a battery compartment, a mounting for a lamp (45), a head assembly (23) which can be unscrewed from the barrel (21), the head assembly (23) including a lens (26) for the light from the lamp (45), and on/off electrical contacts adapted to be operated by partial screwing and unscrewing of the head assembly (23).

Maglicals torch uses a miniature lamp (45) with rearwardly extending electrodes (43, 44) which extend through a so-called upper insulator receptacle (47) having extensions configured to mate with a so-called lower insulator receptacle (41), the lower and upper insulator receptacles(41, 47) forming the mounting for the lamp (45).

The present invention provides an electric torch as claimed in the claims.

The invention will be described by way of example with reference to the drawings, in which: Fig. 1 illustrates an electric torch embodying the invention in section, showing it switched on; Fig. 2 corresponds to Fig. l but shows the torch switched off; Fig. 3 is an exploded perspective view of a lamp mounting of the torch, without the lamp; Fig. 4 is a plan view of a switch housing of the torch: Fig. 5 is a section on line 5-5 of Fig. 4; Fig. 6 is a plan view of a fixed electrical contact ring of the torch; and Fig. 7 is a side view of the contact ring of Fig. 6.

The illustrated torch 10 comprises the following parts:- a barrel-shaped metal body .................. 11 a metal head ................................ 12 a bezel ..................................... 13 a metal rear cover .......................... 14 a fixed electrical contact ring ............. 15 a lamp holder of metal ...................... 16 a lamp holder base of metal ................. 17 a conductor pin of metal .................... 18 a conducting cap of metal ................... 19 a first conducting spring of metal .......... 20 a second conducting spring of metal ......... 21 a reflector of aluminium-coated molded plastic 22 an insulating switch housing of molded plastic 23 a lens ...................................... 24 a plastic ring .............................. 25 first, second and third elastomeric 0-rings . 26-28 a lamp ...................................... 29 a spare lamp ................................ 30 The barrel-shaped metal body 11 forms a compartment 31 for two electric batteries 32 in series. The batteries 32 can be replaced by unscrewing the rear cover 14 from the body. The first 0-ring 26 forms a water-tight seal between the body 11 and the rear cover 14. The first conducting spring 20 seats in a recess 14a in the rear cover 14 and makes electrical contact with the electrically negative rear end 32a of the battery 32.

The spare lamp 30 occupies a second recess 14b which extends from recess 14a. The spare lamp 30 is retained in place, until required, by the spring 20.

The bezel 13 is screwed onto the metal head 12 and secures thereto the reflector 22 and the lens 24, to form a head assembly H. The reflector 22 is of molded plastic with a vacuum-plated aluminium surface. The second 0-ring 27 forms a water-tight seal between the head 12 and the lens 24. The third 0-ring 28 forms a water-tight seal between the body 11 and the head 12, which is screwed onto the body 11.

A lamp mounting 33 (Fig. 3) is formed by an assembly of the lamp holder 16, the lamp holder base 17, the conductor pin 18, the conducting cap 19, the second conducting spring 21 and the switch housing 23.

The lamp 29 (identical of course to lamp 30) is a standard miniature lamp and is retained between a cylindrical ring portion 17a, which is externally screwthreaded, of the metal lamp holder base 17 on the one hand and the metal lamp holder 16, which is internally screwthreaded and screwed onto ring portion 17a, on the other hand. This produces good electrical contact with the lamp casing 29a. A flat annular portion 17b of the lamp holder base 17 forms a moving electrical contact. The ring portion 17a of the lamp holder base 17 fits tightly onto a cylindrical portion 23a of the insulating plastic switch housing 23 to hold them assembled together.

The conductor pin 18 is slidably seated in a bore 23b of switch housing 23 and is biased into electrical contact with the end terminal 29b of the lamp 29 by the second spring 21, which occupies an enlarged bore 23c in a cylindrical portion 23d of switch housing 23, between the pin 18 and the cap 19. The spring 21 is retained in the bore 23c by the cap 19, which is pinched at two places - one being shown at 19a - to secure it to portion 23d of switch housing 23.

The plastic ring 25 is fixed inside body 11 rearwardly of switch housing 23 except for the cylindrical portion 23d, which projects therethrough-.

The first spring 20 urges two batteries 32 forwardly, to bring the positive terminal 32b of the front or top battery 32 into electrical and physical contact with the cap 19, an electrical path to the lamp contact 29b being provided by the pin 18 and spring 21, both insulated by the housing 23.

The lamp holder 16 and base 17, which make electrical contact with the lamp casing 29a, are normally electrically insulated from the body 11 by the housing 23.

The fixed contact ring 15 has outer spring tabs 15a which project radially outwardly from an annular portion 15b and which engage the inside surface of the body 11 to secure the contact ring 15 to the body 11 at or near the front end thereof and to make electrical connection via the body 11, the rear cover 14 and the first spring 20 with the rear end 32a of the battery 32.

The contact ring tabs 15a extend radially through slots 23e between axially extending ears 23f of switch housing 23. The ears 23f project axially forwardly of fixed contact member 15, as shown in Figs. 1 and 2.

The distal ends of the ears 23f of switch housing 23 are pressed against a cylindrical ring portion 22a of the reflector 22 by the action of the first spring 20 pressing on the battery 32, which presses on the cap 19 and hence on the switch housing 23.

Hence, when the head assembly H is partially unscrewed from the body 11, moving the reflector 22 progressively forwardly, that is, axially away from the rear cover 14, the lamp mounting 33 also moves progressively forwardly, pushed by the first spring 20, until the flat annular portion 17b (forming the moving electrical contact) of lamp holder base 17 engages the annular portion 15b of the fixed contact ring 15, to switch the torch on, as in Fig. 1. Upon engagement of electrical contacts 15b, 17b, the lamp mounting 33 is prevented from further forward movement, so that any further unscrewing of the head assembly H moves the reflector 22 forwardly relative to the lamp 29 to vary the spread, or conversily the focus, of the light beam.

When the head 12 is screwed down again on the body 11, the reflector portion 22a presses on the ears 23f of switch housing 23 and hence moves the lamp mounting 33 axially towards the rear cover 14, disengaging the contacts 15b, 17b to switch the torch off.

In both conditions, that is, on and off, water-tightness is maintained by the 0-ring 28.

Thus the torch 10 is waterproof, and yet attractive.

The head assembly (of head 12, bezel 13, lens 24 and bring 27) can be completely unscrewed from body 11 leaving 0-ring 28 and lamp mounting 33 still attached to body 11.

Claims

1. An electric torch (10) comprising:a barrel-shapped body (11) of metal, forming a battery compartment (31), and means (14, 20) for removably retaining at least one battery (32) in said compartment (31) and making electrical connection between a rear end (32a) of the at least one battery (32) and said body (11), and spring-biasing said at least one battery (32) towards a front end of the body (11); a head assembly (H) comprising a metal head (12), a reflector (22) and a lens (24) assembled together and screwed onto the front end of the body (11) so as to be capable of being unscrewed therefrom by means of the metal head (12) being screwed onto the front end of the body (11); a fixed electrical contact member (15) at or near the front end of the body (11), therewithin; a lamp mounting (33) comprising a member (23) of molded plastic assembled together with parts (16-19, 21) of metal for mounting of a lamp (29), a first said metal part (19) being adapted and arranged to make electrical contact with a front terminal (32b) of said at least one battery, a second said metal part (17b) forming a moving electrical contact, the lamp mounting (33) being inside, and movable axially of, the body (11) to bring the moving electrical contact (17b) into and out of electrical contact with the fixed electrical contact member (15) for switching the lamp (29) on and off, said first and second metal parts (19, 17b) being electrically connected to respective terminals of the lamp (29), both when switched on and when switched off; at least one portion (23f) of the lamp mounting (33) projecting forwardly of the fixed electrical contact member (15) and being engageable by a portion (22a) of the head assembly (H), whereby said axial movement of the head assembly (H) relative to the body (11) by screwing and unscrewing of the head assembly (H) causes corresponding axial movement of the lamp mounting (33) and hence switching off and on of the lamp (29).

2. A torch (10) as claimed in claim 1 wherein said second metal part (17b) is annular and is engageable with an annular portion (15b) of said fixed electrical contact member (15).

3. A torch (10) as claimed in claim 2 wherein radially outwardly projecting portions (15a) of said fixed electrical contact member (15) project through spaces (23e) in said member (23) of molded plastic into engagement with said body (11).

4. A torch (10) as claimed in 1, 2 or 3 wherein said at least one forwardly projecting portion (23f) of the lamp mounting (33) is at least one portion (23f) of the member (23) of molded plastic.

5. A torch (10) as claimed in any preceding claim wherein the portion (22a) of the head assembly (H) engageable by the at least one forwardly projecting portion (23f) of the lamp mounting (33) is a portion (22a) of the reflector (22).

6. A torch (10) as claimed in any preceding claim wherein said first metal part (19) is a metal cap mounted on the member (23) of molded plastic, said parts (16-19, 21) of metal also comprising a pin (18) to engage the lamp (29) and a spring (21) between the pin (18) and the cap (19).