Year: 1899

page_text: Date of Application (in United Kingdom), 1st June, 1899
Complete Specification Left, 1st Mar., 1900-Accepted, 7th Apr., 1900
I, HARRY PHILLIPS DAVIS, of 327, Neville Street, Pittsburgh, in the County
of Allegheny and State of Pennsylvania, United States of North America, Elec-
trical Engineer, do hereby declare the nature of this invention to be as follows;--
My invention relates to circuit breakers and in particular to devices of this
description having a fuse wire through which the current passes, so that the pas-
sage through the circuit of a current exceeding a pre-determined amount melts
the fuse wire and causes the interruption of said circuit.
The object of my invention is to provide a circuit breaker which shall be espe-
cially suitable for use with circuits of high voltage, and for this purpose I arrange
that upon breakage of the fuse the terminals of the circuit shall become separated
by a considerable space, so that although a comparatively short fuse only is used,
there shall be no danger of any are being maintained between the fuse terminals
for a sufficiently long time to injure the same, or to be harmful to the circuit
which it is desired to protect.
When dealing with higher voltage circuits, it is desirable that the operation
of reinserting the fuse shall be entirely free from danger to the attendant, and
I therefore provide that the device to which the fuse is directly connected or of
which it forms part, shall be able to be detached from the terminals and the fuse
inspected or a fresh fuse inserted after which the device can be re-attached to
the circuit terminals; I further arrange a simple means for opening the circuit
at the fuse terminals without damaging the fuse.
According to my invention, the device consists of two members hinged together
and also connected by the fuse wire, the whole being arranged in such a manner
that when the fuse wire breaks, the two members of the device are forced or fall
apart, and the terminals to which the fuse wire was attached are separated by a
considerable air space.
The invention is shewn in the accompanying drawings in which,
Figure 1 is a side elevation of my improved circuit breaker attached to the
terminals of a circuit.
Figure 2 is a similar view shewing the upper portion of one of the members.
Figure 3 is a section on the line -- Figure 1 looking upward.
Figure 4 is an elevation of the upper portion of the second member of the
device looking in the direction of the arrow y shewn in Figure 1.

page_text: Figures 2, 3 and 4 are drawn to an enlarged scale.
1 is an insulating supporting base; 2 and 3 are the circuit terminals provided
with connectors 4, the front end or head 5 of the terminal 2 being provided with
a notch 6 opening upward and the head of the terminal 3 having side contact
surfaces S. One member 9 of the circuit breaker consists of a long rod of
insulating material upon the upper end of which is a fuse terminal 11 in connec-
tion with a spring contact piece 15, the arms 14 of which make frictional contact
with the sides of the head 5, being connected by a pin 16 which rests in the
notch 6 of the said head. The upper portion of the terminal 11 has a socket 17
in which is clamped a block 18 of carbon or other infusible material. This
block has a central perforation 19 through which passes the fuse wire 46, the
end of the fuse wire being held by means of a clamp. One portion 22 of the said
clamp is secured to or forms part of the socket 17, the other portion 24 being
pivoted on to the stud 25 and provided with an arm 26 to which is fastened a
cord 27. The clamping head 28 of the part 24 is in the form of an arc of a circle
eccentric to the pin 25, so that the fuse wire can be tightly nipped between the
fixed and movable jaws of the clamp. The clamping means is very clearly
shewn in Figure 4.
The member 9 of the circuit breaker is provided opposite the terminal 3 of the
circuit with a contact device consisting of a U-shaped spring contact 29, the
arms of which will make frictional contact with the side of the head 7 of the
terminal 3 when the pin 16 is supported in the notch 6 of the upper terminal
and the member 9 is pressed inward toward the lower one; this is clearly shewn
in Figure 3.
The member 9 is provided with a bracket 30 having projecting arms 30 to
which the other member 34 of the circuit breaker is hinged. Between the
arms 30 a spring 33 is secured, the upper end of said spring serving to press
the member 34 of the circuit breaker outward and the lower end serving as a
buffer to prevent it falling down further than the position shewn in dotted lines
in Figure 1.
The upper end of the member 34 has a fuse terminal 37 clearly shewn in
Figure 2. said terminal is provided with a socket 40 in which is clamped a
block 41 of carbon or other infusible material having a central perforation through
which the fuse wire 46 passes, its outer end being secured to a binding screw 43.
The terminal 37 is connected to the spring contact 29 by means of a flexible
connection 44 which may pass up inside the member 34 or may be attached to
the outside if desired, or in place of a flexible connection the current may pass
through the hinge or bracket 30.
As will be seen from the general view Figure 1, the fuse wire 46 which may be
of any suitable length, connects the upper ends of the members of the circuit
breaker and prevents the same from moving apart, the other ends of the members
being connected by the hinge. Consequently when the fuse breaks through an
excessive current passing through, the member 34 will fall down to the position
shewn in dotted lines in Figure 1 and the fuse terminals will be separated by a
large gap, which effectually prevents the formation of an are. If it is desired
to open the circuit, the cord 27 is pulled rotating the part 24 thereby releasing
one end of the fuse wire from the clamp and permitting the member 34 to fall.
For inspection or renewal of a fuse the entire circuit breaker may be detached
from the terminals 2 and 3 by withdrawing the parts 29 from contact with the
head of the lower terminal, and then raising the device so that the pin 16 is
withdrawn from the notch 6 of the upper terminal. The fuse can then be
inspected or a fresh one inserted and the device readily replaced in position.
The member 9 is shewn as projecting some distance below the bracket 30; this
enables tlie device to he readily detached from the circuit terminals, and at the
same time the circuit breaker is located at such a distance above the floor that
the member 34 will not descend low enough to strike the heads of persons who
way chance to be beneath when the circuit breaker opens.

page_text: I have here shewn a particular form of my improved circuit breaker, but it
is clear that it may be modified in various details without departing from the
scope of the invention. In the form shewn the member 9 is normally fixed and
the member 34 movable, but any person skilled in the art will be able from the
foregoing description to construct forms in which both members are movable, the
fuse terminals on said members being, if necessary, each connected by a flexible
connection with the terminals of the circuit.
Tated the 1st day of Tune 1800
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant,
I, HARRY PHILLIPS DAVIS, of 327, Neville Street, Pittsburgh, in the County
of Allegheny and State of Pennsylvania, United States of North America, Elec
trical 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 statenient:-
My invention relates to circuit breakers and in particular to devices of this
description having a fuse wire through which the current passes, so that the pas-
sage through the circuit of a current exceeding a pre-determined amount melts
the fuse wire and causes the interruption of said circuit.
The object of my invention is to provide a circuit breaker which shall be espe-
cially suitable for use with circuits of high voltage, and for this purpose I arrange
that upon breakage of the fuse the terminals of the circuit shall become separated
by a considerable space, so that although a comparatively short fuse only is used,
there shall be no danger of any are being maintained between the fuse terminals
for a sufficiently long time to injure the same, or to be harmful to the circuit
which it is desired to protect.
When dealing with higher voltage circuits, it is desirable that the operation
of reinserting the fuse shall be entirely free from danger to the attendant, and
I therefore provide that the device to which the fuse is directly connected or of
which it forms part, shall be able to be detached from the terminals and the fuse
inspected or a fresh fuse inserted after which the device can be re-attached to
the circuit terminals; I further arrange a simple means for opening the circuit
at the fuse terminals without damaging the fuse.
According to my invention, the device consists of two members hinged together
and also connected by the fuse wire, the whole being arranged in such a manner
that when the fuse wire breaks, the two members of the device are forced-or fall
apart, and the terminals to which the fuse wire was attached are separated by a
considerable air space.
The invention is shewn in the drawings left with my Provisional Specification
in which,
Figure 1 is a side elevation of my improved circuit breaker attached to the
terminals of a circuit.
Figure 2 is a similar view shewing the upper portion of one of the members.
Figure 3 is a section on the line. Figure 1 looking upward.
Figure 4 is an elevation of the upper portion of the second member of the
device looking in the direction of the arrow y shewn in Figure 1.
Figures 2, 3 and 4 are drawn to an enlarged scale.
1 is an insulating supporting base; 2 and 3 are the circuit terminals provided

page_text: This
with connectors 4, the front end or head 5 of the terminal 2 being provided with
a notch 6 opening upward and the head 7 of the terminal 3 having side contact
surfaces S. Que member 9 of the circuit breaker consists of a long rod of
insulating material upon the upper end of which is a fuse terminal 11 in connec-
tion with a spring contact piece 15, the arms 14 of which make frictional contact
with the sides of the head 5, being connected by a pin 16 which rests in the
notch 6 of the said head. The upper portion of the terminal 11 has a socket 17
in which is clamped a block 18 of carbon or other infusible material.
block has a central perforation 19 through which passes the fuse wire 46, the
end of the fuse wire being held by means of a clamp. One portion 22 of the said
clamp is secured to or forms part of the socket 17, the other portion 24 being
pivoted on to the stud 25 and provided with an arm 26 to which is fastened a
cord 27. The clamping head 28 of the part 24 is in the form of an arc of a circle
eccentric to the pin 25, so that the fuse wire can be tightly nipped between the
fixed and movable jaws of the clamp. The clamping means is very clearly
shewn in Figure 4.
The member 9 of the circuit breaker is provided opposite the terminal 3 of the
circuit with a contact device consisting of a U-shaped spring contact 29, the
arms of which will make frictional contact with the side of the head 7 of the
terminal 3 when the pin 16 is supported in the notch 6 of the upper terminal
and the member 9 is pressed inward toward the lower one; this is clearly shewn
in Figure 3.
The member 9 is provided with a bracket 30 having projecting arms 30° to
which the other member 34 of the circuit breaker is hinged. Between the
arms 30 a spring 33 is secured, the upper end of said 'spring serving to press
the member 34 of the circuit breaker outward and the lower end serving as a
buffer to prevent it falling down further than the position shewn in dotted lines
in Figure 1.
The upper end of the member 34 has a fuse terminal 37 clearly shewn in
Figurd 2, said terminal is provided with a socket 40 in which is clamped a
block 41 of carbon or other infusible material having a central perforation through
which the fuse wire 46 passes, its outer end being secured to a binding screw 43.
The terminal 37 is connected to the spring contact 29 by means of a flexible
connection 44 which may pass up inside the member 34 or may be attached to
the outside if desired, or in place of a flexible connection the current may pass
through the hinge or bracket 30.
As will be seen from the general view Figure 1, the fuse wire 46 which may be
of any suitable length, connects the upper ends of the members of the circuit
breaker and prevents the same from moving apart, the other ends of the members
being connected by the hinge. Consequently when the fuse breaks through an
excessive current passing through, the member 34 will fall down to the position
shown in dotted lines in Figure 1 and the fuse terminals will be separated by a
large gap, which effectually prevents the formation of an arc. If it is desired
to open the circuit, the cord 27 is pulled rotating the part 24 thereby releasing
one end of the fuse wire from the clamp and permitting the member 34 to fall.
For inspection or renewal of a fuse the entire circuit breaker may be detached
from the terminals and 3 by withdrawing the parts 29 from contact with the
head of the lower terminal," and then raising the device so that the pin 16 is
withdrawn from the notch 6 of the upper terminal. The fuse can then be
inspected or a fresh one inserted and the device readily replaced in position.
The member 9 is shewn as projecting some distance below the bracket 30: this
enables the device to be readily detached from the circuit terminals, and at the
same time the circuit breaker is located at such a distance above the floor that
the member 34 will not descend low enough to strike the heads of persons who
may chance to be beneath when the circuit breaker opens.
I have here shown a particular form of my improved circuit breaker, but it
is clear that it may be modified in various details without departing from the

page_text: scope of the invention. In the form shewn the member 9 is normally fixed and
the member 34 movable, but any person skilled in the art will be able from the.
foregoing description to construct forms in which both members are movable, the
fuse terminals on said members being, if necessary, each connected by a flexible
connection with the terminals of the circuit.
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. A circuit breaker consisting of two members hinged together and provided
with infusible circuit terminals between which is connected a fuse wire, so that
when the wire breaks the members separate and a large gap is formed between
the said terminals for the purpose specified.
2. In.a circuit breaker of the kind described clamping one or both ends of the
fuse wire in such a manner that said fuse wire can be released by pulling a cord
or the like, substantially as described.
3. The means for detachably connecting a circuit breaker to a circuit substan-
tially as described.
4. Circuit breakers constructed substantially as describal with reference to
the accompanying drawings.
Dated the 1st day of March 1900.
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham.