A New or Improved Telephone Transmitter:
Year: 1892

page_text: Date of Application, 6th July, 1892
Complete Specification Left, 18th Nov., 1892-Accepted, 31st Dec., 1892
PROVISIONAL SPECIFICATION.
A New or Improved Telephone Transmitter:
I, ROWLAND HUGHES JONES, of Vron Haulog, Colwyn Bay, in the County
of Denbigh, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to a new or improved telephone transmitter in which the
diaphragm usually employed for the reception of the sound waves produced by the
speaker's voice is dispensed with.
My invention in its usual form consists of two blocks of carbon placed horizontally
one over the other and bridged across by a number of carbon rods, the ends of
which may enter recesses in the said blocks. By means of an adjusting screw or
adjusting screws I am able to vary the pressure between the said blocks and rods.
I attach one terminal of each of the circuit wires to each block so that the said
circuit is completed through the blocks and rods.
When the sound waves produced by the voice are directed between the carbon
blocks that is to say in a direction normal to the direction of the rods and parallel
to the plane of the blocks the two blocks tend to separate more or less and therefore
vary the pressure between them and the rods.
I enclose the parts mentioned in a suitable case furnished with a mouthpiece
across which I generally stretch gauze or the like to shield the carbon rods from
injury.
By making the upper block of sufficient mass or by attaching a weight thereto
I may dispense with the adjusting screws.
In some cases I may by electrically connecting the lower ends of the rods and
fixing them in position dispense with the lower block altogether.
The rods and blocks are not necessarily of carbon.
any other suitable microphonic material.
Dated this 6th day of July 1892.
may substitute therefor
TITTAA
ROWLAND H. JONES,
Per J. G. L.
COMPLETE SPECIFICATION.
A New or Improved Telephone Transmitter.
I, ROWLAND HUGHES JONES, of Vron Haulog, Colwyn Bay, in the County of
Denbigh, Engineer, 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:-
My invention relates to a new or improved telephone transmitter in which the
diaphragm usually employed for the reception of the sound waves produced by the
speaker's voice is dispensed with.
My invention in its usual form consists of two blocks of carbon placed horizontally
one over the other and bridged across by a number of carbon rods, the ends of
which may enter recesses in the said blocks. By means of an adjusting screw or
adjusting screws I am able to vary the pressure between the said blocks and rods.
I attach one terminal of each of the circuit wires to each block so that the said
circuit is completed through the blocks and rods.
When the sound waves produced by the voice are directed between the carbon
'

page_text: "
blocks that is to say in a direction normal to the direction of the rods and parallel
to the plane of the blocks the two blocks tend to separate more or less and therefor
vary the pressure between them and the rods.
I enclose the parts mentioned in a suitable case furnished with a mouthpiece
across which I generally stretch gauze or the like to shield the carbon rods from
injury.
In some cases I may by electrically connecting the lower ends of the rods and
fixing them in position dispense with the lower block altogether.
The rods and blocks are not necessarily of carbon. I may substitute therefor any
- other suitable microphonic material.
Having thus described my invention in general terms so as to define its scope
I shall now proceed to describe an actual instrument embodying the best form of
my invention with which I am acquainted at this date. For the purposes of such
description I shall refer to the sheets of drawings which I have appended hereto in
the several figures of which similar letters of reference indicate similar parts.
Figure 1 is a front elevation of my telephone transmitter with the front of the
case removed.
Figure 2 is an end elevation with one end of the case removed and showing only
one row of the carbons.
Figure 3 is a plan of the upper block and
Figure 4 is a front elevation of the mouth piece.
In these figures A is the wall plate by which the instrument is secured to a wall
or the like and B B B B are the binding screws thereon. C C¹ C² C³ C* and C
are, respectively, the top, the bottom, the left side, the right side, the front and the
back walls of the case containing the microphonic elements and the induction
coil D. E is the mouth piece fixed in the front wall of the case and bearing the
sheet of wire gauze F which is placed at the inner end of the mouth piece for the
purpose of acting as a shield for the carbons. G is the upper block and H
the lower block whilst J J J represent the carbon rods. The block H is fixed to
the bottom of the case by screws or otherwise. The upper block G is perforated
by orifices through which pass the necks jjj of the rods J. The said rods J J J
have other necks which are soldered in recesses in the block H. The con-
nections are as usual, the primary circuit passing from the block G to the block H
through the rods J.
Although I have shown my instrument with an induction coil, as is usual in the
case of lines of any length, I would say that owing to the low resistance of my
instrument it will be apparent that it is particularly applicable for direct working
without an induction coil.
It will be seen that when the instrument is spoken into the sound waves passing
between the two blocks will tend to raise or lower the block G (and thus decrease
or increase the pressure of the said block G upon the shoulders of the rods J) and
consequently to vary the resistance between the said two blocks, or in other words
vary the resistance of the primary circuit.
I have spoken of the ends of the rods entering recesses in the blocks, this however
is not essential as my invention would act equally well if projections on the blocks
entered recesses in the rods; or again such recesses and projections might be
dispensed with altogether, in which case the rods might be soldered to the lower
block and the upper block simply rest upon the upper extremities of the rods.
It will be seen that in the instrument illustrated I have dispensed with the
adjusting screws by which I may when desired regulate the initial pressure between
the blocks and the rods. As a rule it is better to dispense with such adjusting
screw, and to make the upper block G of the required weight in the first place.
I find it convenient to make the said upper block of the following dimensions,
namely, 9 inches in length and width, and of an inch in thickness. This block
I generally cut from hard retort carbon. Its weight is then about one ounce.
rods I generally cut from ordinary arc lamp carbons of ten millimetres or two-fifths
of an inch diameter.
The

page_text: 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. The new or improved telephone transmitter substantially as set forth.
2. The arrangement and combination of parts substantially as set forth.
3. The combination substantially as set forth of a number of vertical conducting
rods and a conducting block resting thereon substantially as set forth.
4. The combination of two conducting blocks placed horizontally one over the
other and a number of conducting rods bridging across from one of the said blocks
to the other and either with or without an adjusting screw serving to adjust the
pressure between the said blocks and rods.
Dated this 17th day of November 1892
J. G. LORRAIN, M. Inst. E.E., M. Inst. M.E.,
Norfolk House, Norfolk Street, Strand, London, W.C.,
Chartered Patent Agent.