A New or Improved Telephone Transmitter.
Year: 1891

page_text: Date of Application, 6th Jan., 1891
Complete Specification Left, 6th Oct., 1891-Accepted, 28th Nov., 1891
PROVISIONAL SPECIFICATION.
A New or Improved Telephone Transmitter.
I, ERHARD LUDWIG MAYER, of 11 Billiter Square, London, in the County of
Middlesex, Engineer do hereby declare the nature of this invention to be as
follows:-
My invention relates to a new or improved telephonic transmitter whereby speech
can be transmitted with great clearness and distinctness.
In carrying my invention into effect I employ two or more pieces of carbon or
other suitable material to constitute the microphonic contact or tension regulator.
These pieces are placed so as to be actuated by the movements of a diaphragm and
are arranged in the form of an elbow or toggle, so that a very wide variation of
pressure or of extent of contact surface may result from a comparatively small
amplitude of vibration of the diaphragm.
Dated this 6th day of January 1891.
J. G. LORRAIN, M.I.E.E., M.I.M.E.,
Norfolk House, Norfolk Street, London, W.C., Applicant's Patent Agent.
COMPLETE SPECIFICATION.
A New or Improved Telephone Transmitter.
I, ERHARD LUDWIG MAYER of 11 Billiter Square, London in the County of
Middlesex, 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 telephonic transmitter whereby speech
can be transmitted with great clearness and distinctness
In carrying my invention into effect I employ two or more pieces of carbon or
other suitable material to constitute the microphonic contact or tension regulator.
These pieces are placed so as to be actuated by the movements of a diaphragm and
are arranged in the form of an elbow or toggle, so that a very wide variation of
pressure or of extent of contact surface may result from a comparatively small
amplitude of vibration of the diaphragm.
Having now described my invention in general terms I shall proceed to describe
it in greater detail and for that purpose I shall refer to the figures in the accom-
panying sheets of drawings which illustrate certain forms of my invention.
these figures similar letters refer to similar or equivalent parts.
In
Figure 1 shows in vertical section the diaphragm and tension regulator of one
form of my new or improved telephone transmitter and
Figure 2 is a plan view of the same parts.
A is the diaphragm which may be made of any of the usual materials but which
I prefer to construct of aluminium carefully annealed to get rid of any inequality
of molecular tension. To A is attached in any of the usual ways the front support B
of the tension regulator. The rear surface of B is hollowed out to receive the fore
end of the front toggle piece C. This also is hollowed out to receive the fore
end of the rear toggle piece D. E is the back support of the tension regulator
and is hollowed out to receive the rear end of the rear toggle piece D. It is
rigidly attached to the back of the instrument case or other fixed part. B, C, D
and E may be made of any of the usual microphonic materials but I prefer to
construct them of carbon. It will be seen that B, C, D and E engage one another

page_text: by projections entering recesses; but I desire it to be understood that where pro-
jections are shown in the drawings recesses may be substituted and vice versa.
Thus, for example, instead of the fore end of D entering a recess in C, D might be
recessed to receive the rear end of C. Projections and recesses are not however
necessary as the parts may simply abutt against one another. To prevent lateral
movement of the carbons I find it convenient to employ two vertical glass rods f, f
as shown; and to prevent disengagement of the toggle pieces when the instrument
is for any reason turned upside down I find that another glass g, rod placed hori-
zontally as shown, serves well.
Figure 3 shows in plan a modified form of tension regulator constructed under
my present invention. It differs from that shown in Figures 1 and 2 in that for
the single rear toggle piece D and back support E two rear toggle pieces D¹
and D2 and two back supports E¹ and E2 are substituted.
Figure 4 shows in plan another modified form of my invention.
It differs from
that shown in Figures 1 and 2 merely in that a union piece H is inserted between
the toggle pieces C and D.
Figure 5 is yet another form of my invention specially designed for cases in
which I require the transmitter to be of low resistance. This form differs from that
shown in Figures 1 and 2 in that the tension regulator is triplicated, the three
microphone elements being coupled up in quantity. In this form I generally
electro-deposit copper upon the carbon pieces in order to still further lessen the
resistance.
Other modifications may be made without departing from the spirit of my inven-
tion, but the forms shown are typical.
In practice I prefer to employ the form of my invention shown in Figures 1
and 2 on account of its simplicity; and I have found that an instrument of this
form and constructed to the following weights and dimensions gives excellent
results. Diaphragm 38 inches in diameter and of thickness equal to No. 22 standard
guage, constructed of well annealed aluminium. Front toggle piece of arc lamp
carbon rod 1 inch in length, 4 millimetres thick and 9 grains in weight. Rear
toggle piece of similar carbon 1 inch long, 8 millimetres thick and 36 grains in
weight. With an instrument so constructed I prefer to employ an induction coil
having a primary winding of half an ohm and a secondary winding of two hundred
and fifty ohms resistance I also prefer to arrange the two toggle pieces so that
the front one slopes to an angle of about 45 degrees with the vertically placed
diaphragm whilst the rear toggle piece is nearly horizontal. The tension regulator
may be connected up in the usual way but I generally connect the positive lead to
the back support and the negative lead to the front support.
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. A telephone transmitter having a tension regulator constructed substantially
as set forth.
2. In a telephone transmitter a tension regulator consisting essentially of two
toggle pieces arranged to form a toggle or elbow, the said pieces being freely
articulated at each of their extremities substantially as set forth.
הנימד
E. L. MAYER.
Witness:
J. G. LORRAIN, M. Inst. E.E., M. Inst. M.E.,
Norfolk House, London, W.C., Applicant's Patent Agent.