Improvements in Magneto-electric Bells or Generators in connection with Telephonic Call Apparatus.
Year: 1889

page_text: Date of Application, 14th Sept., 1889
Complete Specification Left, 3rd June, 1890-Accepted, 19th July, 1890
PROVISIONAL SPECIFICATION.
Improvements in Magneto-electric Bells or Generators in connection
with Telephonic Call Apparatus.
I, ARTHUR GREENWOOD, of Woodhall Hills, Calverley, near Leeds in the County
of York, Electrician, do hereby declare the nature of this invention to be as
follows:
This invention consists of Improvements in Magneto Electric Bells or Generators
in connection with magneto electric or electric extension call bells, and is intended for
use in signalling in connection with telephone instruments and lines.
This invention is based upon the fact of a telephone 'subscriber' having his
telephone instruments (including magneto generator) fixed in a telephone call box or
similar room provided for that purpose, and one, or any number of, extension call
bells (in connection with the said telephone instruments) fixed elsewhere. When a
person goes to the telephone instruments to make a call, he, upon turning the
generator handle, rings the extension bells at the same time, and thus calls up other
persons (who do not know he is there) to attend to telephone, unless some means are
provided whereby he can cut off extension bells before using telephone. The present
general method of doing this is provided in the shape of a switch, movable by hand;
as this, however, is dependent on the will of the user of the telephone, in many cases
the said user either forgets to switch off extension bells before using (causing the
difficulty before mentioned) or forgets to switch on the extension bells after using,
thereby leaving himself liable to miss any call which may afterwards be sent from the
Telephone Exchange or other end of line.
This invention is for the purpose of improving upon the before mentioned switching
arrangements by automatically switching the extension bell or bells out of circuit
when the magneto generator is in motion, and by automatically switching the
extension bell or bells into circuit when the magneto generator is at rest.
To accomplish this I utilise the motion made by the generator shaft of a magneto
bell in a horizontal and lateral direction; this motion is used in ordinary magneto
bells for the purpose of shunting the armature circuit when the armature or generator
is at rest, and is made by means of a spiral spring arrangement known as the cut out.
I employ this motion for the purpose of switching off and on the extension bell or
bells automatically, by causing the generator shaft, handle and gearing, to break the
connection between armature and line or earth (made by a contact spring) when the
armature, gearing and shaft are at rest; and by causing the armature to be connected
through the said contact spring to line or earth when the armature, gearing and shaft
are in motion.
In this invention I cause a separate contact to be made for the end of the generator
shaft when at rest (instead of allowing the shaft to make contact with the armature
contact spring, as done in ordinary magneto bells).
I make the following arrangements for disconnecting the armature circuit when
armature is at rest and connecting it when armature is in motion :-
In the first arrangement of this invention I fix the armature contact spring in such
position, that a spring or lever hereinafter described shall, when the armature and
shaft are at rest, cause the armature contact spring to be disconnected from the
armature, by holding the said contact spring apart.
I also cause a spring or lever to be fixed from any side of the magneto bell case
(preferably the side on which are the handle and driving wheel) to the generator
shaft; the said spring or lever must be entirely insulated from the shaft and every
part of generator; I attain this effect by attaching to the spring or lever a piece of

page_text: ebonite, vulcanite or other insulating substance, against or through which the shaft
revolves. The said spring or lever I adjust to be in such position that when the shaft
and armature are in motion, the shaft will revolve freely against or through the
insulating part of the spring or lever, and that when the shaft and armature come to
rest the said spring or lever shall be moved, by means of the before mentioned spiral
spring arrangement known as the cut out, against the armature contact spring causing
the latter to be disconnected from the armature the whole of the time the said
armature and shaft are at rest; the end of the shaft, during the same time, making
contact with the before mentioned separate contact piece.
I make the electrical connections in this case in the following manner :-
From incoming or line wire to magneto bell coils and thence to generator shaft and
framework (to which one end of the armature coil is connected); from the armature
contact spring (with which the other end of armature coil makes contact when in
motion) to outgoing or earth wire. I attach one side of extension bell to the before
mentioned separate contact piece for shaft, and other side of extension bell to outgoing
or earth wire; thus when the armature and shaft are put in motion (thereby
generating a current) the only circuit along which the generated current can pass is
through armature and magneto bell coils to line on the one side and through armature
contact spring to earth on the other side; the extension bell circuit is disconnected by
the breaking of the connection between the end of the shaft and the before mentioned
separate contact piece, which is caused by drawing away the shaft from the said
contact piece in order to work the armature. This is the same motion by which the
armature contact spring is allowed to make contact with the armature. Any current
received from the Telephone Exchange or other end of line passes through magneto
bell coils, generator shaft, separate contact piece, and extension bells to earth. The
armature and shaft being at rest, the armature circuit is disconnected in the before
described manner.
In a second arrangement of this invention I allow the armature contact spring to
remain permanently in contact with the armature; I fix two contact pieces, one a
movable spring and the other a fixed contact, either vertically from the bottom of the
magneto bell case, or horizontally from the door of the said case, or in any other
convenient position, but they must be fixed in such manner that by means of an
insulating washer, which I fix on the generator shaft, the movable contact spring will
be held apart or disconnected from the fixed contact piece when the generator shaft is
at rest, and released so as to make contact with the said fixed contact piece whilst the
generator shaft is in motion.
I also fix the separate contact piece, as in the first arrangement, to make contact
with the end of the generator shaft when the latter is at rest. I alter the electrical
connections in the following manner :-
outgoing or earth wire
Instead of connecting the armature contact spring direct to
I connect it to the before mentioned movable contact spring and connect the before
mentioned fixed contact piece to the outgoing or earth wire. By these means I
accomplish the same end as in the first arrangement.
In a third arrangement of this invention I cause by means of an arrangement of
bevelled wheels for driving gear, the following effect:- -When in motion, armature to
make contact with armature contact spring, and generator shaft to break contact from
separate contact piece mentioned in the previous arrangements; when at rest,
armature to be, held away or break contact from armature contact spring, and
generator shaft to be held against the separate contact piece before mentioned.. The
electrical connections to be made as in the first arrangement. The result hereby
obtained will be the same as in the previous arrangements.
If the line used is a metallic, that is, a return line wire substituted for outgoing or
earth wire, this invention in all its arrangements will act as herein described; for the
circuit, instead of being to earth, will be complete along the return line substituted
for earth.
I do not confine myself to the arrangements herein described, as my invention

page_text: consists of applying, by various methods, the horizontal and lateral motion and cut
out of the generator shaft to the purpose of automatically disconnecting and connecting
extension bells.
Dated this Thirteenth day of September 1889.
ARTHUR GREENWOOD.
COMPLETE SPECIFICATION.
Improvements in Magneto-electric Bells or Generators in connection
with Telephonic Call Apparatus.
I, ARTHUR GREENWOOD, of Woodhall Hills, Calverley, near Leeds in the County
of York, 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'consists of improvements in magneto electric bells or generators in
connection with magneto electric or electric extension call bells, and is intended for
use in signalling in connection with telephone instruments and lines.
This invention is based upon the fact of a telephone subscriber having his
telephone instruments (including magneto generator) fixed in a telephone call box or
similar room provided for that purpose, and one or any number of extension call bells
(in connection with the said telephone instruments) fixed elsewhere. When a person
goes to the telephone instruments to make a call, he, upon turning the generator
handle, rings the extension bells at the same time, and thus calls up other persons
(who do not know he is there) to attend to telephone, unless some means are provided
whereby he can cut off extension bells before using telephone. The present general
method of doing this is provided in the shape of a switch, movable by hand; as
this, however, is dependent on the will of the user of the telephone, in many cases the
said user either forgets to switch off extension bells before using (causing the
difficulty before mentioned) or forgets to switch on the extension bells after using,
thereby leaving himself liable to miss any call which may afterwards be sent from
the Telephone Exchange or other end of line.
This invention is for the purpose of improving upon the before mentioned switching
arrangements by automatically switching the extension bell or bells out of circuit
when the magneto generator is in motion, and by automatically switching the
extension bell or bells into circuit when the magneto generator is at rest.
To accomplish this I utilise the motion made by the generator shaft of a magneto
bell in a lateral and horizontal direction; this motion is used in ordinary magneto
bells for the purpose of shunting the armature circuit when the armature or generator
is at rest, and is made by means of a spiral spring arrangement known as the 'cut out.'
I employ this motion for the purpose of switching off and on the extension bell or
bells automatically, by causing the generator shaft, handle and gearing to break the
connection between armature and line or earth (made by a contact spring) when the
armature gearing and shaft are at rest; and by causing the armature to be connected
through the said contact spring to line or earth when the armature gearing and shaft
are in motion.
In this invention I cause a separate contact piece G to be made for the end of the
generator shaft when at rest (instead of allowing the shaft to make contact with the
armature contact spring as done in ordinary magneto bells).
In order that my invention may be readily understood I now proceed to describe
the accompanying drawings on which are shewn some of the various arrangements by
which this invention may be carried into practice. The same letters of reference
indicate the same parts throughout the corresponding figures.
In the first arrangement of this invention I fix the armature contact spring F in such
position that a spring or lever A, hereinafter described shall, when the armature D
and shaft B are at rest, cause the armature contact spring F to be disconnected from
the armature D, by holding the said contact spring F apart.

page_text: Figures 1, 2 and 3 refer to the first arrangement of this invention. Figure 1 is
the front elevation of the generating part of a magneto bell. A is a spring or lever
which I cause to be fixed from any side of the magneto bell case (preferably the side
on which are the handle and driving wheel) to the generator shaft B; the said spring
or lever A must be entirely insulated from the shaft B and every part of the generator;
I attain this effect by attaching to the spring or lever A, a piece of ebonite, vulcanite
or other insulating substance C, against or through which the shaft revolves. The
spring or lever A I adjust to be in such position that when the shaft B and the
armature D are in motion the shaft will revolve freely against or through the
insulating part C of the spring or lever A, and that when the shaft B and armature D
come to rest the spring or lever A shall be moved, by means of the before mentioned
spiral spring arrangement known as the 'cut out' (lettered E), against the armature
contact spring F causing the latter to be disconnected from the armature D the whole
of the time the said armature D and shaft B are at rest; the end of the shaft B
during the same time making contact with the before mentioned separate contact
piece G. Figure 2 is a plan of this arrangement. The dotted line shews the
position of the armature contact spring F when the generator shaft B and armature D
are in motion; the line F shews position of the said contact spring when the shaft B
and armature D are at rest. A is the spring or lever before mentioned. Figure 3
represents section at H H of spring or lever A, shaft B and insulation C.
I make the electrical connections in this case in the following manner :—
From incoming or line wire to magneto bell coils and thence to generator shaft B
and framework I (to which one end of the armature coil D is connected); from the
armature contact spring F (with which when in motion the other end of armature
coil makes contact) to outgoing or earth wire. I attach one side of extension bell to
the before mentioned separate contact piece G and the other side of extension bell to
outgoing or earth wire; thus when the armature D and shaft. B are put in motion
(thereby generating a current) the only circuit along which the generated current
can pass is through armature D and magneto bell coils to line on the one side and
through armature contact spring F to earth on the other side; the extension bell
circuit is disconnected by the breaking of the connection between the end of the
shaft B and the contact piece G, which is caused by drawing away the shaft B from
the said contact piece G in order to work the armature D. This is the same motion
by which the armature contact spring F is allowed to make contact with the
armature D.
Any current received from the Telephone Exchange or other end of line passes
through magneto bell coils, generator shaft B, separate contact piece G and extension
bells to earth. The armature D and shaft B being at rest, the armature circuit is
disconnected in the before described manner.
Figures 4 and 5 illustrate a second arrangement of this invention. In this case I
allow the armature contact spring F to remain permanently in contact with the
armature D; I fix two contact pieces, one a movable spring K and the other a
fixed contact piece L, either vertically from the bottom of the magneto bell case
(as shewn in figure 4) or horizontally from the door of the said case or in any other
convenient position, but they must be fixed in such manner that by means of an
insulating washer M, which I fix on the generator shaft B, the movable contact
spring K, will be held apart or disconnected from the fixed contact piece L when the
generator shaft B is at rest, and released so as to make contact with the said fixed
contact piece L whilst the generator is in motion.
I also fix the separate contact piece G, as in the first arrangement, to make contact
with the end of the generator shaft B, when the latter is at rest. Figure 5 is a
sketch shewing more clearly the armature contact spring F and separate contact
piece G. I alter the electrical connections in the following manner :-
Instead of connecting the armature contact spring F direct to outgoing or earth
wire I connect it to the before mentioned movable contact spring K and connect the
before mentioned fixed contact piece L to the outgoing or earth wire. By these means
I accomplish the same end as in the first arrangement of this invention.

page_text: If the line used is a metallic, that is, a return line wire substituted for outgoing or
earth wire this invention in all its arrangements will act as herein described; for the
circuit, instead of being to earth, will be complete along the return line substituted
for earth.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is:
The application and use of the lateral motion and cut out of the generator shaft
(whether fixed vertically, horizontally, obliquely or in any other position in the
magneto bell) by various methods to the purpose of automatically disconnecting and
connecting extension call bells.
Dated this Thirtieth day of May 1900
ARTHUR GREENWOOD.