Improvements in and relating to Apparatus for Advertising, Display, Decorative, and such like Purposes.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in and relating to Apparatus for Advertising, Display,
Decorative, and such like Purposes.
I, ERNST BÖHM, of 42 Little Britain, in the City and County of London,
Electrician, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
This invention relates to apparatus for advertising, display, decorative, and such
like purposes.
The invention consists of a tube or tubes of glass bent or curved to the desired
shape so as to form a letter, figure, word, design, or other part of an advertisement
or decorative device, or the like and so connected and mounted as to admit of the
practical application to advertising, display, decorative, and such like purposes of
the well-known brilliant and beautiful effects of the sparking of the electric current
when passing through a vacuum tube.
The tube or tubes may be of white or coloured glass, as desired, and may be
exhausted, or may be filled with nitrogen or other gases.
The tube or tubes being bent or curved to the desired shape, I mount them as
follows:-I lay the tube upon a flat surface of board, millboard, glass, or other
suitable substance prepared for the purpose (this prepared surface or mounting I
shall hereafter for convenience speak of as the board); the ends of the tube are
bent or curved backwards and carried through apertures made in the board to
receive them, and, in like manner, other parts of the tube or tubes, forming con-
nections between letters, words, or parts of a design, may, where advisable, be bent
or curved backwards and carried through apertures in the board made for their
reception and brought again to the front surface.
At each place where a tube passes from the front to the rear of the board or
vice versa, I support and affix the tube to the board by paraffin wax, cement, or other
suitable means for rigidly fastening and maintaining the tube in position.
It is, of course, essential that the tube should be continuous between the electrical
contacts, otherwise the circuit could not flow, and by my method of mounting I am
enabled to make words or designs in continuous tubing of considerable length which,
if not so mounted and supported would be liable to fracture from the least shock or
jar, or from the specific gravity of the tubing itself. I sometimes cover the board
with dark plush, velvet, or other substance, whereby the apertures through which
the tube is carried are concealed and the electrically lighted tube is shown to
greater advantage.
For further protection I place the board with the tube mounted thereon, as
before described, in a suitable frame or case having a glass front or window. The
tube whether exhausted or filled with nitrogen or other gases, is provided with
platinum or other contacts which are connected with terminals upon the outside of
the case to which the leads from an induction coil or transformer, made suitably to
the conditions used, are attached.
My system of mounting tubes as described may be clearly seen by reference to
the accompanying drawings. Figure 1 shews an elevation and Figure 2 a plan of
a board having the name of "E. Bohm & Co." thereon: the said name is formed
from a vacuum tube bent to the shape of the letters and secured to the board:
Figure 3 is a section on the line X X Figure 1 looking in the direction of the arrow
shewn. The ends of the tube are carried through the board as shewn at 6, 6,
Figure 2 and the tube is bent and carried through the board at 7 Figure 2, between
the first letter "E" and the second letter "B," the connection between the two
letters being on the back of the board as shewn at 8 Figure 2. The dotted lines

page_text: in Figure 1 indicate the parts of the tube which are situated at the back of the
board and such parts are clearly shewn in Figure 2.
Where a letter is curved or looped, as for instance in the letter "B" the two
parts of the loop of the tube will lie one upon the other as shewn in Figure 3 so
that the current may flow through every part of the letter, word, or design.
To prevent the diminution of the vacuum, which often occurs by air entering at
the electrical contacts, I adopt the means shewn in section in Figure 4. In each
end of the tube I form a chamber 10 into which protrude the ends of platinum or
other electrical contact pieces 9 and 11. One of these contacts projects into the
interior of the vacuum tube and the other is connected with the source of electricity.
The chamber 10 is filled with mercury which acts as a seal to prevent the entrance
of air and, at the same time, completes the circuit between the electrical con-
tacts 9 and 11.
"
As an illustration of a fanciful design in which my invention may be used in an
effective manner I have shewn in Figure
a representation of the letter " "A
which may be made like an ordinary block letter of wood, or other suitable material
on which vacuum tubes may be laid and mounted and secured in the same manner
as before described. In large letters so produced each part of the letter may be
separately connected with the source of electricity. For example, in the letter
shewn it would be more convenient to connect the vacuum tubes laid upon each leg
and upon the cross piece separately to the electric source than to make the tube
continuous and thus cause one electric current to traverse every part of the
letter.
Another method of mounting a design of this description would be to fix strips of
reflecting glass at an angle to each other and to secure the vacuum tube at the apex
of the angle between them. When the current was sparking through the tube or
tubes the reflection of the mirrors would produce a dazzling effect.
As a modification of my invention I may take vacuum tubes, properly mounted
and connected, and cover them with an opaque envelope from which the word or
words of the advertisement etc. has been cut out or perforated.
With each or any of the methods of using my invention as herein described an
automatic mechanism may be used for making and breaking contact at intervals
so that the current passes through the tube or tubes intermittently, thus enhancing
the effect and economising the electric current required.
I am aware that vacuum tubes have been already formed into letters, words, and
various designs, and therefore I make no claim to the construction and use of
vacuum tubes so made. Hitherto however it has been found impossible to use such
tubes for commercial purposes on account of the fragile nature of the tubes, and
the insufficient manner of supporting them, and therefore I shall claim only the
use of such tubes when mounted in the manner substantially as hereinbefore
described.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
(1) For advertising, display, decorative and such like purposes, the use of a
vacuum tube or tubes formed into the shape of letters, words, or other designs and
provided with electrical contacts which may be connected to any suitable source of
electricity for the purpose of passing the electrical current through the vacuum
tube or tubes, and fixed upon or to a suitable mount stand, or backing in such
manner that these delicate and fragile designs are supported and protected
SO as to be available for the purposes stated substantially as described and
shewn.
(2) In combination with a mount, stand, or backing of any kind, a vacuum tube
or tubes passed through or otherwise connected to the said backing, the vacuum
tube or tubes aforesaid being connected with the source of electricity substantially
as and for the purposes herein before set forth and illustrated.

page_text: (3) The means herein described and shewn in Figure 4 of the accompanying
drawings for preventing the entry of air at the electrical contacts into vacuum
tubes constructed and used in the manner and for the purposes set forth consisting
of two disconnected contacts dipping into a seal of mercury contained in a bulb or
chamber formed in the end of the tube substantially as stated.
(4) My improvements in and relating to apparatus for advertising, display, and
such like purposes substantially as described.
Dated this 30th day of April 1891
"
CASTLE SMITH,
Invention" Office, 54, Fleet Street, London, E.C., Agent for the Applicant.