U.S. patent number 3,730,669 [Application Number 05/211,553] was granted by the patent office on 1973-05-01 for photographic flashlamp unit having control structure on base.
This patent grant is currently assigned to GTE Sylvania Incorporated. Invention is credited to John W. Shaffer.
United States Patent |
3,730,669 |
Shaffer |
May 1, 1973 |
PHOTOGRAPHIC FLASHLAMP UNIT HAVING CONTROL STRUCTURE ON BASE
Abstract
A multilamp flash unit or flashcube having a base upon which is
supported a plurality of percussively-ignitable flashlamps, each
having a primer tube depending therefrom, and a plurality of
preenergized striker springs individually releasable to fire a
respective one of the flashlamps by impact against its primer tube.
The base includes a plurality of bores, into which the primer tubes
are inserted for supporting the flashlamps, and a plurality of
apertures, each adjacent a respective striker spring. The unit is
usable on a camera having a mechanical actuating member that
sequentially is movable into the unit via the apertures, upon
indexing of the unit, to release successive striker springs and
thereby fire successive flashlamps in the unit. A control ramp is
located between each aperture and bore in the flashcube base for
guiding the travel of each striker subsequent to its release to
assure reliable firing of the respective flashlamp.
Inventors: |
Shaffer; John W. (Williamsport,
PA) |
Assignee: |
GTE Sylvania Incorporated
(Danvers, MA)
|
Family
ID: |
22787404 |
Appl.
No.: |
05/211,553 |
Filed: |
December 23, 1971 |
Current U.S.
Class: |
431/361 |
Current CPC
Class: |
G03B
15/0484 (20130101); G03B 15/0489 (20130101); F21K
5/026 (20130101) |
Current International
Class: |
F21K
5/14 (20060101); F21K 5/00 (20060101); G03B
15/03 (20060101); G03B 15/04 (20060101); F21k
005/02 () |
Field of
Search: |
;95/11L
;431/92,93,94,95 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Dority, Jr.; Carroll B.
Claims
What I claim is:
1. Control structure in a flashlamp-containing unit; said unit
being receivable on apparatus having a mechanical actuating member
for firing a flashlamp in said unit; said unit including a base
having an upper surface for supporting said flashlamp and for
supporting a preenergized striker releasable to fire said
flashlamp; said base further having means defining an aperture
adjacent said striker and through which said striker is accessible
to be released by said actuating member to fire said flashlamp; the
control structure comprising:
a ramp on the upper surface of said base between said aperture and
said flashlamp, said ramp substantially defining an inclined plane
rising toward said flashlamp, and said ramp being adapted to be
slidably engaged by said striker during the travel of said striker
subsequent to its release whereby the moving striker is guided to
reliably fire said flashlamp.
2. The control structure of claim 1 wherein said flashlamp is a
percussively-ignitable lamp having a primer tube depending
therefrom, said base further has means defining a bore in the upper
surface thereof for receiving the primer tube of said lamp, the
free end of said primer tube being inserted in said bore to thereby
support said flashlamp on said base, and said ramp is disposed
between said aperture and said bore.
3. The control structure of claim 2 wherein the perimeter of said
aperture in the upper surface of said base lies in a first
horizontal plane, the upper surface of said base proximate said
bore is substantially flat and lies in a second horizontal plane
elevated from said first horizontal plane, and said ramp rises from
said first horizontal plane to said second horizontal plane, said
flat surface proximate said bore being adapted to facilitate
insertion of the primer tube of said lamp into said bore during
assembly.
4. The control structure of claim 2 wherein said flashlamp
comprises: an hermetically sealed, light-transmitting envelope; a
quantity of filamentary combustible material located within said
envelope; a combustion-supporting gas in said envelope; and a
primer secured to and extending from the lower end of said envelope
and in communication therewith, said primer including said tube
sealed in said lower end of said envelope and having an exposed
segment outside said envelope, a wire anvil located within said
tube, and a body of fulminating material located on said wire anvil
intermediate its ends and on that segment of said wire anvil
located in said exposed segment of said tube but spaced from the
inside wall thereof, the lower boundary of said fulminating
material being spaced from the lower end of said wire anvil; and
wherein the upper surface of said base proximate said bore is
elevated from the upper surface of said base proximate said
aperture by the rise of said ramp whereby the depth of said bore is
sufficient to dispose said lower boundary of said fulminating
material within said bore when said primer tube is fully inserted
therein.
5. A base for a multilamp flash unit; said unit including a
plurality of percussively-ignitable flashlamps each having a primer
tube depending therefrom, and a plurality of preenergized strikers
individually releasable to fire a respective one of said
flashlamps; said unit further being receivable on apparatus having
a mechanical actuating member operable to release one of said
strikers to fire its respective flashlamp; the base comprising:
means defining first and second axially spaced surfaces;
means defining a plurality of bores in said second surface for
respectively receiving the primer tubes of said flashlamps to
provide support therefor;
means in said second surface for supporting said preenergized
strikers;
means defining an aperture in said base adjacent each striker and
through which aperture the respective striker is accessible to be
released by said actuating member to fire its respective flashlamp;
and,
a ramp on said second surface between each bore and aperture, said
ramp substantially defining an inclined plane rising toward the
respective bore, and said ramp being adapted to be slidably engaged
by a respective one of said strikers during the travel of the
striker subsequent to its release.
6. The base of claim 5 wherein a plurality of said bores, ramps and
apertures are symmetrically arranged in a circular pattern about
the center of said second surface, each of said apertures is a slot
having a circumferentially arcuate shape, and each of said ramps
has a circumferentially arcuate shape.
7. The base of claim 6 wherein the elevation of said ramp lies in
the range of about 0.001 inch to about 0.040 inch.
8. A multilamp flash unit receivable on apparatus including an
actuating member; the unit comprising:
a substantially planar base defining upper and lower spaced
surfaces and an aperture through the base;
a plurality of flashlamp devices supported on the upper surface of
said base, each device including a percussively-ignitable flashlamp
and a preenergized firing spring individually releasable to impact
against and fire a respective flashlamp, said firing spring
including a striker portion located closely adjacent said upper
surface and over said aperture to be released by said actuating
member to fire the flashlamp; and,
a striker guiding ramp on the upper surface of said base between
each aperture and flashlamp, said ramp substantially defining an
inclined plane rising toward a respective flashlamp, and said ramp
being adapted to be slidably engaged by the striker portion of a
respective one of said firing springs during the travel of said
striker portion subsequent to its release whereby the moving
striker portion is guided to reliably fire said respective
flashlamp.
9. The unit of claim 8 wherein each of said flashlamps comprises:
an hermetically sealed, light-transmitting envelope; a quantity of
filamentary combustible material located within said envelope; a
combustion-supporting gas in said envelope; and a primer secured to
and extending from the lower end of said envelope and in
communication therewith, said primer including a tube sealed in
said lower end of said envelope and having an exposed segment
outside said envelope, a wire anvil located within said tube, and a
body of fulminating material located on said wire anvil
intermediate its ends and on that segment of said wire anvil
located in said exposed segment of said tube but spaced from the
inside wall thereof, the lower boundary of said fulminating
material being spaced from the lower end of said wire anvil; and
wherein sd base further has a plurality of bores in the upper
surface thereof each for receiving the primer tube of a respective
one of said lamps to provide support therefore, each striker
guiding ramp is disposed between a respective aperture and bore;
and, the upper surface of said base proximate each bore is elevated
from the upper surface of said base proximate a respective aperture
by the rise of the respective ramp therebetween whereby the depth
of said bore is sufficient to dispose said lower boundary of said
fulminating material within the bore when said primer tube is fully
inserted therein, the striker portion of each firing spring being
releasable to impact against the primer tube of its respective
flashlamp and thereby fire said flashlamp.
10. The unit of claim 9 wherein each of said firing springs is a
folded torsional spring comprising a substantially hairpin
torsional section having two segments joined by a bight, said
striker portion projecting from one of said segments, a supporting
foot projecting from the other of said segments and fixedly mounted
on the upper surface of said base, and a catch formed at the tip of
said foot, said striker portion crossing said foot with said catch
restraining said striker portion in a cocked condition.
Description
BACKGROUND OF THE INVENTION
This invention relates to photographic flashlamp units and, more
particularly, to multilamp flash units, such as flashcubes, having
lamps of the percussive primer type and the means employed to fire
them.
The structure of a commercially available percussive-type
photoflash lamp is illustrated in FIG. 1. It comprises a length of
glass tubing defining an hermetically sealed lamp envelope 2
constricted at one end to define an exhaust tip 4 and shaped to
define a seal 6 about primer 8 at the other end thereof. The primer
8 comprises a metal tube 10, a wire anvil 12 coaxially disposed
therein, and a band of fulminating material 14 coated on the wire
anvil intermediate its ends. A combustible, such as filamentary
zirconium 16, and a combustion-supporting gas such as oxygen are
disposed within the lamp envelope. The outer surface of the
envelope 2 is covered with a suitable protective lacquer coating
(not shown), such as cellulose acetate, to render the glass tube
substantially shatterproof.
The lamp is mechanically fired by the impact of a striker against
primer tube 10. The striker indents the thin walled tube 10 to
thereby contact and ignite the fulminating material 14 whereby it
deflagrates up through the tube to ignite combustible 16 disposed
within the lamp envelope. A refractory bead 30, fused to the wire
anvil 12 just above the inner mouth of the primer tube 10,
eliminates burnthroughs and functions as a deflector to deflect and
control the ejection of hot particles of fulminating material from
the primer tube.
In order to provide high lamp reliability at realistic low striker
impact energies, a very sensitive composition of fulminating
material is required. Hence, any rubbing or pinching of the band of
fulminating material 14 must be avoided if the lamp is to withstand
normal shipping and handling. Accordingly, as shown in the enlarged
detail view of FIG. 2, the primer assembly of the lamp is
specifically designed to avoid accidental firing. More
specifically, wire anvil 12 is provided with a proturberance, or
head, 20 at the end thereof which is disposed within the primer
tube 10. Further, a first set of diametrically disposed
protuberances 22 are provided intermediate the ends of anvil 12,
and a second set of diametrically disposed protuberances 24 are
located above the first set of protuberances. To provide the
desired coaxial centering of the anvil within tube 10, the set of
protuberances 24 are located so as to lie in a plane substantially
at right angles with respect to the plane in which the set of
protuberances 22 lie. A crimp 28 in the metal tube on or about head
20 positively anchors wire 12, and the protuberances 22 and 24
stabilize it within the primer tube 10. The fulminating material 14
may be dip applied to the wire anvil below the protuberances 22 and
subsequently removed from the lower portion of the anvil including
head 20 so that the entire body of fulminating material is located
between the head 20 and the protuberances 22. A spacing y is
provided between band 14 and head 20 so as to leave an axial
clearance between the lower boundary 26 of the fulminating material
and the upper inside surface of crimp 28. The diameter of the head
20 and the diameter of a circumscribed circle about the
protuberances 22 and 24 are each larger than the diameter of the
coating of fulminating material 14 so as to also provide a radial
clearance X between the fulminating material and the the inner wall
of primer tube 10. Clearances X and Y must be sufficient to prevent
contact between the fulminating material 14 and the inner wall of
the metal tube 10 even when the lamp is vibrated such that the
anvil moves slightly relative to the tube in which it is
mounted.
One embodiment of a multilamp flash unit of the type with which the
present invention is concerned is illustrated in FIG. 3. This unit,
which may be referred to as a percussive flashcube 32, comprises a
substantially rectangular base 34 along each side of which is
arranged a percussive flashlamp 36, of the type described. Each
lamp 36 is provided with a respective reflector 38 and a respective
preenergized striker spring 42, and the assemblage of lamps,
striker springs and reflectors is enclosed in a transparent cover
40 secured to the base 34.
A single lamp-striker spring assembly, as mounted on a prior art
type of base, is more clearly shown in the simplified enlarged view
of FIG. 4. The flashlamp 36 is supported on the base by means of a
bore 44 into which the primer tube 10 is inserted. Spring 42 is a
folded torsion device typically formed from 0.021 inch music wire
about 2.5 inches long. The wire is shaped to form a hairpin
torsional section having segments 46 and 48 and a bight 50. The end
portion of segment 46 is shaped to define a stationary supporting
foot 52 (not shown in this view), the tip of which is shaped to
define a catch 54. The end portion of segment 48 is shaped to
define a striker 56, which when the spring is preenergized, or
cocked, as shown, crosses over the supporting foot 52 and is
restrained by catch 54. The stationary supporting foot is seated in
an elongated slot formed in the base on or near a diagonal thereof,
said slot being sufficiently shallow so that the catch 54 formed on
the free end of foot 52 will project a relatively substantial
distance above the plane of the upper surface of the base.
Displacement of the cocked striker 56 to release it from the catch
54 and thus permit it to strike the primer tube 10 and fire the
lamp, is effected by a suitable actuating member 58 moving up
through an aperture 60 provided therefor in the base. When the
member 58 pushes the striker 56 upwardly a distance sufficient to
clear the top of the catch 54, the striker swings clockwise, as
shown by the arrow, and hits and indents the impact sensitive
primer tube 10 at high velocity to cause deflagration of the
fulminating material located therein and thus ignite the
combustible foil 16.
The lower surface of the flashcube base is provided with a suitable
center post or the like (not shown) for mounting on apparatus such
as a camera and providing a means whereby the flashcube may be
rotated 90.degree. after a lamp has been flashed so that another
lamp may be advanced to the firing position. Hence, the actuating
member 58 may be part of a camera mechanism designed to enable a
photographer to flash a lamp in synchronization with the tripping
of the camera shutter to take a picture. The mechanical power input
to the actuating member from the shutter responsive triggering
mechanism is quite limited in practical camera designs, and a
minimum upward travel for the member 58 is desirable. One type of
camera mechanism suitable for use with percussive flashcubes is
described in U.S. Pat. No. 3,602,618.
Referring again to the flash lamp primer (FIG. 2), the location of
the lower edge 26 of the band of fulminating material 14 is subject
to certain manufacturing tolerances which are essentially
impossible to eliminate with automated equipment. In order to
prevent contact of the fulminating material 14 with the tube crimp
28, as discussed hereinbefore, it is desirable to provide a large
spacing Y between the anvil head 20 and the band 14 of fulminating
material. This helps assure freedom from inadvertent lamp flashing.
The spring striker 56, however, must indent tube 10 so that the
resulting impact pinches the fulminating material 14 between the
tube 10 and anvil 12. If the striker indents the tube at or below
the lower boundary 26 of the fulminating material, the lamp will
most probably fail to flash. Consequently, any upward movement of
the lamp tube 10 out of the bore 44 in the flashcube base, as could
occur due to vibration during manufacture, handling or use, can
result in decreased product reliability.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention
to provide an improved flash unit of the type containing a
percussive flashlamp and a preenergized striker for firing the
lamp.
A principal object of the invention is to provide a percussive
multilamp flash unit that maintains high reliability after severe
handling, and which has substantially less likelihood of
inadvertent lamp flashing during manufacture, handling and use.
Another object is to provide a percussive flashcube for cameras
which provides the above-mentioned objects while at the same time
retaining the desired minimum travel distance for the camera
actuating member.
These and other objects, advantages and features are attained, in
accordance with the principles of this invention, by providing a
ramp on the upper surface of the flashcube base between each
flashlamp and the aperture through which the camera actuating
member passes to release the overlying striker spring. The ramp
substantially defines an inclined plane rising toward the primer
tube of the flashlamp and is adapted to be slidably engaged by the
striker during its travel subsequent to release. In this manner,
the moving striker is guided to cause impact of the fulminating
material sufficiently above its lower boundary to reliably fire the
flashlamp. This type of control structure on the flashcube base is
particularly advantageous in that it simultaneously permits both
the desired low initial striker position, with minimized travel for
the camera actuating member, and a sufficient clearance between the
primer tube crimp and the fulminating material to reduce the
probability of inadvertent lamp flashing.
BRIEF DESCRIPTION OF THE DRAWINGS
This invention will be more fully described hereinafter in
conjunction with the accompanying drawings in which:
FIG. 1 is an elevational view partly in section of a percussive
type photoflash lamp to which previous reference has been made;
FIG. 2 is a fragmentary detail on an enlarged scale of the primer
of the lamp of FIG. 1 to which previous reference has been
made;
FIG. 3 is a simplified perspective view of a percussive flashcube
with a portion broken away for clarity and to which previous
reference has been made;
FIG. 4 is an elevational cross-section providing a simplified
illustration on an enlarged scale of a single lamp-firing spring
assembly mounted on a prior art type of flashcube base, and to
which previous reference has been made;
FIG. 5 is an elevational cross-section providing a simplified
illustration on an enlarged scale of a single lamp-firing spring
assembly mounted on a flashcube base in accordance with the present
invention;
FIG. 6 is a fragmentary view on an enlarged scale of a single
lamp-firing spring assembly of the flashcube of FIG. 3 embodying
the principles of this invention; and
FIG. 7 is a plan view of the base of the flashcube of FIG. 3 in
accordance with the invention with the several spring members shown
in full and the several flashlamps associated therewith shown in
phantom.
DESCRIPTION OF PREFERRED EMBODIMENT
The present invention may be embodied in a percussive flashcube of
the type generally shown in FIG. 3 by means of the base structure
illustrated with more particularity in FIGS. 5-7. The simplified
view of FIG. 5 is somewhat similar to FIG. 4 in that it shows a
percussive flashlamp 36 and a torsion spring 42, both of the type
described hereinbefore, mounted on a percussive flashcube base. In
accordance with the present invention, however, the base 34 of FIG.
5 includes a ramp 62 on its upper surface between the aperture 64,
through which actuating member 58 passes, and the bore 66 in which
the primer tube 10 of lamp 36 is inserted. The ramp 62 may be
molded as an integral part of the base 34 and is formed to
substantially define an inclined plane rising toward the primer
tube 10 of the flashlamp. Thus, whereas in FIG. 4 the upper surface
of the prior art flashcube base proximate bore 44 and aperture 60
is coplanar, FIG. 5 shows the upper surface of base 34 proximate
bore 66 elevated from the upper surface of base 34 proximate
aperture 64 by the rise of the ramp 62. In this manner, the depth
of the bore 66 is made sufficient to dispose the lower boundary 26
of the fulminating material in primer 8 (FIG. 2) well within the
bore when primer tube 10 is fully inserted therein. As a result of
this configuration, ramp 62 is adapted to be slidably engaged by
the striker 56 during its travel, subsequent to release from catch
54 by the upward movement of actuating member 58, to thereby guide
the moving striker 56 toward impact against primer tube 10 in a
manner operative to reliably fire the flashlamp 36.
During the development of the percussive flashcube, it was observed
that if the tip of the high velocity striker 56 made any contact
with other objects during its travel, such as scuffing an inside
face of the flashcube cover 40, the kinetic energy of the firing
spring and, consequently, the reliability of lamp flashing were
substantially reduced. It was quite surprising, therefore, to find
that the provision of a ramp 62 on the upper surface of the
percussive flashcube base raises the primer tube indent height
without either adversely affecting lamp reliability or causing the
striker to bounce too high and hit, for example, the glass envelope
of the lamp. These favorable results are probably due to the fact
that the ramp slidably engages the smooth underside of the striker
wire 56, as opposed to the cusp of the striker tip; also, the
velocity is greater at the tip of the striker than near its
fulcrum, and the leverage ratio and force characteristics
differ.
The primer tube 10 cannot be moved farther downward in the prior
art flashcube base. Similarly, the size of the anvil head 20 (FIG.
2) and the elevation of crimp 28 above the bottom of the tube 10
have been minimized. The only alternative way of increasing
clearance between tube crimp and fulminating material to reduce
inadvertent flashing, while at the same time giving a sufficient
minimum spring strike height on the primer tube to assure reliable
operation, would be to increase the overall base thickness and
initial height of the spring striker. As pointed out previously,
mechanical considerations of the camera actuating member drive
mechanism contraindicates such a change in the percussive
flashcube-to-camera interface dimensions.
Accordingly, the ramp control structure of the invention is
particularly advantageous in that it permits both the desired low
initial striker position with minimized travel for the camera
actuating member 58 and a sufficient clearance between the primer
tube crimp 28 and the lower boundary 26 of the fulminating material
(FIG. 2) to reduce the probability of inadvertent lamp
flashing.
A more detailed illustration of the percussive flashcube base
structure according to the invention is shown in FIGS. 6 and 7.
Referring first to FIG. 6 flash lamp 36 is supported on the base 34
by means of its primer tube 10 being fully inserted in bore 66.
Also mounted on the base 34 is a folded torsion spring 42 of the
type described hereinbefore. Again, the spring includes the pair of
segments 46 and 48 joined by bight 50, with the end portion of
segment 46 being shaped to define the stationary supporting foot
52, the tip of which is shaped to define catch 54. Portions of the
foot 52 and catch 54 are hidden in FIG. 6. Projecting from the
lower end of segment 48 is the striker 56 which, when the spring is
preenergized, or cocked, as shown, crosses the supporting foot 52
and is restrained by the catch 54. The stationary supporting foot
is seated in an elongated slot formed in the base 34 on or near a
diagonal thereof, the slot being sufficiently shallow to permit
catch 54 to project above the upper surface of the base 34.
Initially the striker 56 may be formed at an angle of about
90.degree. to the stationary supporting foot 52, although the angle
through which the striker is rotated to position it behond catch
54, as shown, may be of any value that does not cause overstressing
of the wire. A center post 68 on the upper surface of the base 34
provides a suitable bearing surface for the heel of the striker
during cocking, and it also aids in preventing accidental
displacement of the spring 42 sufficient to free the striker from
the catch some time after cocking and before firing is
intended.
As previously described, striker 56 overlies and is adjacent to the
aperture 64 whereby it is accessible to be released by the
actuating member 58. In this instance, aperture 64 comprises a slot
having a circumferentially arcuate shape. In accordance with the
invention, the ramp 62 begins at or near the end of slot 64 nearest
to the lamp 36 and rises to a height Z (FIG. 5) by the time it
reaches the bore 66 holding primer tube 10. A horizontal flat area
70 may be provided about the bore 66 to facilitate insertion of the
primer tube 10 into the bore. Thus, the perimeter of aperture 64 in
the upper surface of the base 34 lies in a first horizontal plane,
while the upper surface of base 34 proximate bore 66 is
substantially flat and lies in a second horizontal plane elevated
from the first horizontal plane, with the ramp 62 rising from the
first horizontal plane to the second horizontal plane. The total
elevation Z of the ramp 64 may vary from about 0.001 inch to about
0.040 inch, if desired; I prefer to use a ramp that rises 0.010
inch above the rest position of the striker 56, which is the upper
terminating surface of slot 64.
The bottom or lower face of the base 34 is provided with a suitable
center post or the like (not shown) for mounting on a camera and
providing a means whereby the flashcube may be rotated 90.degree.
after the lamp has been flashed so that another lamp may be
advanced to the firing position. As illustrated in FIG. 7, each of
the four flashlamps 36 is provided with its own firing mechanism as
shown in detail in FIGS. 5 and 6 and described above. The hairpin
torsional sections of the springs are clustered in the space behind
the reflectors 38 (FIG. 3), with a clearance being provided along
the lower edges of these reflectors to permit free operation of the
strikers. The four sets of bores 66, ramps 62 and apertures 64 are
symmetrically arranged in a circular pattern about the center of
the upper surface of base 34, with each of the apertures 64
comprising a slot having a circumferentially arcuate shape, and
each of the ramps 62 having a circumferentially arcuate shape.
As previously described, displacement of each cocked striker 56, to
release it from catch 54 and thus permit it to strike a respective
primer tube 10 and fire the respective lamp, is effected by the
actuating member 58 moving up through the slot 64. As noted before,
member 58 may be actuated by and in synchronism with the shutter
mechanism of a camera upon which the flashcube is mounted. When
member 58 pushes the striker 56 upwardly a distance sufficient to
clear the top of catch 54, the striker swings clockwise in a
circular arc as shown by the arrows in FIGS. 6-7. In this instance,
however, the control ramp 62, by virtue of its position, incline
and arcuate shape, engages the underside of the moving striker to
guide its path of travel whereby the striker indents the
impact-sensitive primer tube 10 so as to reliably pinch the band of
fulminating material 14 well above its lower boundary 26 (FIG. 2).
This high velocity impact causes deflagration of the fulminating
material up through the tube 10 to ignite the combustible foil
16.
In summary, the base control ramps 62 effectively raise the minimum
height on the lamp primer tube 10 that the striker 56 indents upon
camera activation, while at the same time permitting a desirable
low initial position for the spring striker 56. Such a base
configuration permits increased clearance between the primer tube
crimp 28 (FIG. 2) and the lower boundary 26 of the fulminating
material, thereby giving a lower probability of inadvertent lamp
flashes during manufacture, handling and use of the product. The
control ramps also increase the reliability of lamp operation in
the event of upward lamp displacement in the flashcube base as may
occur, for example, when the cube is dropped. A further advantage
is that such lamp movement is less liable to occur because the
increased base material about the primer tube, as described herein,
provides a better grip, on the tube by the percussive flashcube
base.
Although the invention has been described with respect to a
specific embodiment, it will be appreciated that modifications and
changes may be made by those skilled in the art without departing
from the true spirit and scope of the invention. For example, while
the invention has been described with respect to flashcubes, ti
will be understood the use of a ramp control structure to attain
the aforementioned advantages may also be employed with other types
of flash units, such as single lamp units, linear arrays of lamps,
and multilevel or bidirectional arrays of lamps.
* * * * *