Title:
MULTIFLASH DEVICE, SUCH AS FLASHCUBE, WITH MECHANICALLY IGNITABLE FLASHLAMPS
United States Patent 3702582


Abstract:
To prevent spurious firing of flashbulbs in a flashcube in which a striking echanism is provided, adapted to be released by a camera release pin and to strike an ignition tube having ignition material therein, a safety retaining device in the form of a ring is provided bearing against the sear pins on the flashcube to prevent dislocation of the striking arm. The safety device is lifted off its seat against the sear pins only when the flashcube is inserted on the camera, by engagement of projections formed on the ring with the camera locating projections positioning the flashcube on the camera housing.



Inventors:
Schilling, Werner (Heidenheim, DT)
Lukas, Josef (Augsburg, DT)
Application Number:
05/158967
Publication Date:
11/14/1972
Filing Date:
07/01/1971
Assignee:
PATENT-TREUHAND-GESELLSCHAFT FUR ELEKTRISCHE GLUHLAMPEN MBH
Primary Class:
Other Classes:
431/269
International Classes:
G03B15/04; (IPC1-7): G03B15/04; F21K5/02
Field of Search:
95/11L,11R,11.5 24
View Patent Images:
US Patent References:



Primary Examiner:
Greiner, Robert P.
Claims:
claim

1. A multiflash device for use with a camera having a multiflash fitting comprising:

2. A multiflash device as claimed in claim 1, wherein the projections formed on the ring snap into said apertures, and are movable by engagement with the camera fitting to lift the ring off the sear pins 9.

3. A multiflash device as claimed in claim 1, wherein the ring is made of resilient material.

4. A multiflash device as claimed in claim 3, wherein the ring is made of resilient plastic.

5. A multiflash device as claimed in claim 1, wherein the projections 12 have their terminal ends formed with radially outwardly extending lugs 14.

6. A multiflash device as claimed in claim 5, wherein the lugs are wedge-shaped.

7. A multiflash device as claimed in claim 1, wherein a reflector is a quadruple reflector, four mechanically ignitable flashlamps are provided, and the multiflash device is a flashcube.

Description:
Cross reference to related U.S. Pat. No. 3,576,156.

The invention relates to a multiflash device and particularly to a flashcube which is equipped with mechanically ignitable flashlamps. This flashcube is designed analogous to the conventional flashcubes with electrically ignitable flashlamps and consists of a cube-shaped, light transmissive envelope which surrounds a quadruple reflector seated on a mounting plate. The mounting plate is provided on its outer surface with a slip-on column which is designed to hold the flashcube in an appropriate fitting provided on the camera. Four mechanically ignitable flashlamps are inserted in the mounting plate in such way that their ignition tube will be inserted in pocket bores provided therefor.

The striking mechanisms necessary for ignition of the flashlamps are located inside the flashcube (see U.S. Pat. No. 3,576,156). These mechanisms include springs having striking arms held in a pretensioned position by sear pins located on the mounting plate.

If a lamp is to be ignited, a release pin synchronized with the shutter release mechanism is moved upwards by the camera and projects through an aperture in the mounting plate provided therefor. It lifts the striking arm, held in tensioned position by means of the sear pin, until it can no longer be retained by the sear pin and, due to its spring tension, snaps from the tensioned position to its rest position, striking the ignition tube of the flashlamp and initiating ignition thereof. It is an advantage of this construction that only low force has to be applied by the camera and by the release pin in order to furnish the relatively great striking force for ignition of the flashlamp. The low release force, however, may lead to undesired spurious ignition of the flashlamps, particularly during transportation, since a sufficiently large release force may occur spuriously, for instance, from impact. Moreover, the release points of the percussive springs are exposed due to the apertures in the mounting plate so that an unintentional release might occur by the action of small sharp objects. This might happen, for instance, if the flashcube taken out of the packing is put into a suit pocket.

SUBJECT MATTER OF THE INVENTION

A safety or retaining device is provided installed in the multiflash device, i.e., the flashcube, which prevents an undesired release of the striking arms of the striking mechanisms onto the flashcube in case the latter is not inserted into the fitting or holder of the camera.

The safety device, in a preferred form of the invention, is a plastic ring, snap-fitting with four projections into the apertures of the mounting plate in which the locating projections of the flash fitting of the camera are engaging. The plastic ring is normally resting on the pins holding the striking arms in tensioned position so that the striking arms cannot move out of their prestretched positions; undesired spurious ignition of the flashlamps is prevented. When the flashcube is inserted in the holder of the camera, the camera locating projections push the safety ring upwards, by engagement with the ring projections, which preferably are provided with sloping ends. This permits the striking arms to be lifted by the camera release pin projecting from below to clear the sear pins inserted on the flashcube mounting plate and ignition of the flashlamps can take place.

A multiflash device according to the invention is described by way of the following figures.

FIG. is an exploded perspective view of a multiflash device with its component parts.

FIG. 2 is a sectional detail along line A--A of FIG. 1.

As is to be seen from FIG. 1, the multiflash device is composed of a light-transmissive, cube-shaped cap 1, a quadruple reflector 2, four flashlamps 3 and the mounting plate 4. The quadruple reflector may consist of a folded foil strip with four deep-drawn reflectors or of a single compact reflector manufactured by injection molding. It is loosely seated on the mounting plate 4 and is held in its position by the cover cap 1. The four mechanically ignitable flashlamps 3 are fixedly inserted in the mounting plate. The tubes containing the igniting material and projecting externally of the lamp bulb are stuck in the pocket or blind bores 6 provided therefor in the mounting plate. Four striking mechanisms 7 are incorporated in the mounting plate, only one of them being illustrated in the figure. The striking mechanism is designed as a spring and is provided with a striking arm 8 which is held in a pretensioned position by means of a sear pin. Sear pin 9 may be embedded in or cast integral with the mounting plate; or the striking mechanism may be bent such that it forms, simultaneously, the sear. In order to release the striking arm from its prestressed position, it is lifted over sear pin 9 by means of a release pin extending from the camera, not illustrated, which engages in the mounting plate 4 through recesses 10. This lets the striking arm snap into its rest position, striking the ignition tube 5 of the mechanically ignitable flashlamp which extends in the pocket bore 6, and igniting the flashlamp.

According to the invention, and in order to avoid any spurious undesired ignition of the flashlamp during transportation or within the flashcube when the latter is not fitted to a camera, a retaining ring 11 is provided, made, for example, of plastic. This ring is equipped with four resilient projections 12. They are preferably integral with the ring and obtain their resiliency due to the ring material consisting of plastic. They are formed with sloping end portions 14, forming wedge-shaped lugs. The ring is slipped over the striking mechanisms 7 and snap-fits with its four projections into apertures 13 provided in the mounting plate. The camera fittings designed for flashcubes have webs provided at camera jack projections designed to engage in the apertures 13 in order to insure an exact fit and precise location of the flashcube in the camera fitting. Upon insertion of the flashcube on the camera body, projections 12 on the retaining ring 11 extending in the apertures 13 are pushed upwards by the camera webs of the flash fitting and the ring 11 is placed in raised position by the flexible projections 12, provided with sloping ends. This releases the striking mechanisms since ring 11 is no longer resting on the sear pin 9 and the striking arm 8 can be lifted over sear pin 9 by a camera release pin projecting through recess 10; ignition of a flashlamp can take place under control of the camera release pin, but not otherwise.