Year: 1886

page_text: I, JOHN LORIMER Corbett of 69 Union Street in the City of Glasgow, Waichumaker,
do hereby declare the nature of this invention to be as follows:-
My invention relates to telephone transmitters of the kind wherein variations of
pressure between contact points of metal and carbon or similar material, produced by
sound waves, are transformed into electrical impulses in a telephone circuit and it has
for its object to obtain greater sensitiveness and delicacy of action in such apparatus.
To that end my invention consists in suspending or balancing the contact piece con-
nected to one terminal of the line upon a pivot pin or lighi spindle so that at the
point of contact it may bear upon the block or piece connected to the other terminal
of the line with the pressure due merely to the tendency of the pivotted piece to
attain the position of stable equilibrium. The suspended piece may be either the
carbon button or the metallic contact point of the transmitter, or a carbon rod having
in it a platinum or other pin may form one part and a stationary or movable carbon
block may form the other part of the contact points, the metallic pin or point being
adjustable in each case. The suspended or balanced part may be hung from a pivot
pin or be carried by an arm having a counter-balancing weight, the use of springs.
being dispensed with.
In one construction of the apparatus the carbon block is of cylindrical or spheroidal
formation and is carried upon a spindle which may be turned periodically to bring a
fresh surface of the block into contact with the metallic point. A brush or scraper in
contact with the carbon block is provided for cleaning the surface as the block is
turned and a pencil or piece of graphite may be fitted in contact with the rotatory
carbon block to impart to it a surface coating of fresh carbon.
A ratchet is or may
be provided in connection with the spindle carrying the carbon block and may be
operated to partially rotate said block by the movement of the arm or hook upon
which the telephone is hung.
In telephonic transmitters of the improved construction herein before described I
find it unnecessary to provide a vibrating diaphragın.
CRUIKSHANK & FAIRWEATHER,
Glasgow, Agents.

page_text: 1, JOHN LORIMER CORBETT of 69 Union Street, in the City of Glasgow, Watch-
maker, 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 telephone transmitters of the kind wherein variations of
pressure between contact points of metal and carbon or similar material, produced by
sound waves, are transformed into electrical impulses in a telephone circuit and it has
for its object to obtain greater sensitiveness and delicacy of action in such apparatus.
To that end my invention consists in suspending or balancing the contact piece con-
nected to one terminal of the line upon a pivot pin light spindle or the like so
that at the point of contact it may bear upon ilie block, or piece connected to the other
terminal of the line with the pressure due merely to the tendency of the pivotied
piece to attain the position of stable equilibrium. The suspended piece may be either
the carbon button or the metallic contact point of the transmitter, or a carbon rod
having in it a platinum or other pin may form one part and a stationary or movable
carbon block may form the other part of the contact points, the metallic pin or point
being adjustable.in cach case. The suspended or balanced part may be hung from a
pivot pin or be carried by an arm having a counter-balancing weight, the use of springs
being dispensed with.
.
In one construction of the apparatus the carbon block is of cylindrical or spheroidal
formation and is carried upon a spindle which may be turned periodically to bring a
fresh surface of the block into contact with the metallic point. A brush or scraper in
contact with the carbon block is provided for cleaning the surface as the block is
turned and a pencil or piece of graphite may be fitted in contact with the rotatory-
carbon block to impart to it a surface coating of fresh carbon. A ratchet is or, may
be provided in connection with the spindle carrying the carbon block and may be
operated to partially rotate said block by the movement of the arm or hook upon which
the telephone is hung.
In the accompanying drawings figure 1 is an elevation showing one form of the
improved telephonic transmitter which consists of a box or slab A, having upon it a
metallic plate B, to which are connected by pivots, ball and socket joints or the like,
and suspended from their upper ends a series of carbon rods or blocks C, whose lower
ends rest on a cross rod D, of carbon or metal which is capable of being turned to
present a fresh bearing surface to the suspended rods. The plate B, forms one
terminal and the brackets E, in which the cross rod is carried form the other terminal
of the telephone circuit. Figure 2 shows a similar form of telephonic transmitter in
which the box supporting the transmitting devices is composed of an open tube whose
lower end is of conical form. The terminals is this case are formed by the brackets B,
the course of the, current being down through one rod C, across the rod D, and up
through the adjoining rod to the line, Figure 3 shows a transmitter in which

page_text: a carbon block C, suspended by a pivotted spindle & bears upon a metallic point d,
the transmitting devices which are connected to the line as usual being contained
within a short tube A, over which the message to be transmitted is spoken.
Figures 4 and 5, are respectively a front elevation and sectional side elevation of a
form of transmitter in which the carbon rod or block C, or a metallic point on it
bears upon a disc D of carbon carried by a spindle E, which is partially rotated by
movement communicated to it through a pawl F, and ratchet wheel G, from the
telephone hook H which is depressed by the weight of the telephone hanging on it
and is raised by a spring when the telephone is taken off the hook for use- One
terminal is formed by a spring 1, bearing on the metallic spindle E, and the other hy
a plate J, bearing on a bracket. K, which supports the carbon block C, and which is
provided with a screw for adjusting the position of the carbon block relatively with
the disc D. Figures 6 and 7, show in front elevation and sectional side elevation a
form of transmitter in which a carbon block C, rests on a cylinder D of carbon,
carried by a spindle E, which may be rotated by hand a doctor or scraper M, being
provided for cleaning the surface of the cylinder as it is turned.
In telephone transmitters of the improved construction hereinbefore described I find
it unnecessary to provide a vibrating diaphragm.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed, I declare that what I claim is :-
1. The combinations constituting the several arrangements of improved telephonic
transmitters, herein described with reference to the annexed drawings.
2. In a telephonic transmitter a carbon or other electrode formed by a rod or block
suspended by a pivot pin, spindle or the like whereby the use of a spring is dispensed
with, substantially as described.
3. In a telephonic transmitter a carbon or other electrode formed by a rod or har
adapted to be rotated automatically or by hand and with or without the addition of a
doctor or scraper, substantially as and for the purpose set forth.
CRUIKSHANK & FAIRWEATHER,
62, Saint Vincent Street, Glasgow,
Agents.