Improvements in Fuse Blocks for Electric
Year: 1899

page_text: Improvements in Fuse Blocks for Electric
I, HARRY PHILLIPS DAVIS, of 327, Neville Street, Pittsburgh, in the County of
Allegheny and State of Pennsylvania, U.S.A., Electrical Engineer, do hereby
declare the nature of this invention to be as follows:-
My invention relates to fuse blocks for electric circuits and has for its object
to provide an improved device of that kind in which the fuse block consists of
two parts one of which is fixed and is provided with circuit terminals, and the
other of which contains the fuse and is removable from the fixed portion of the
block so that a fresh fuse can be readily inserted when desirable.
My invention consists in the special constructional arrangements by means of
which the two parts of the fuse block are secured together so that they can be
separated with a minimum expenditure of time and labour and a maximum
degree of safety.
The accompanying drawings shew a fuse block constructed in accordance with
my invention.
Figure 1 is a vertical section.
Figure 2 is a plan partly sectional.
Figure 3 a section on the line 3-3 Figure 1, and
Figure 4 an under plan view shewing the locking portion of the block.
The fixed portion of the block is indicated by the numeral 1 and carries the
spring circuit terminals 2 with which the heads 3 in metallic connection with the
fuse wire make contact when the fuse is in position.
The removable portion of the block 4 has a projecting part 4 which enters an
orifice in the fixed part of the block and is secured therein by means of a screw
clamp 6. The part 4 has a cross channel 7 forming the fuse chamber through
which the fuse wire passes, the ends of the fuse wire being clamped between the
screw caps 3 and plugs which are secured in the part 4 of the fuse block. The
fuse chamber 7 has a lateral opening 8 which passes through the portion 5 and
acts as a blow-out opening to permit the escape of the gases formed when the
fuse is vapourized and to assist in blowing out any arc which may be established
between the fuse terminal. The fixed portion 1 of the fuse block is provided
with flanges 9 which engage with corresponding flanges 10 on the removable por-
tion 4 of the block and a packing ring 11 of india-rubber or other suitable
material is interposed between the two portions so that the fuse and terminals

page_text: will be enclosed in practically water-tight chamber when the two parts of the
block are secured together (see Figures 1 and 3).
The clamping means which I prefer consists of a combined screw and bayonet
catch, the part 5 being provided with two diametrically opposite longitudinal
grooves 12 and 13 and with diagonal or helical grooves 14 and 15 which extend
through nearly the semi-circumference and communicate with the longitudinal
grooves 12 and 13 respectively. 6 is a clamping nut provided with a handle and
having two projections or lugs 16 which engage with the above mentioned
grooves.
The various parts of the fuse block and length of the grooves are so propor-
tioned that when the two parts 1 and 4 are in proper position the lugs 16 on
the clamping nut 6 will be at the inner ends of the grooves 12 and 13 so that
a half turn of the clamping but will force the removable part 4 of the block
against the fixed portion squeezing the packing ring 11.
It is clear that instead of the special form of clamping nut shewn provided
with lugs, an ordinary screw nut may be used. The method of securing the fuse
wire in position by means of the terminal screw caps 3 is well known to electrical
engineers and needs no further description.
Toted the 20th day of July
1800
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.
Improvements in Fuse Blocks for Electric Circuits.
I, HARRY PHILLIPS DAVIS,. of 327, Neville Street, Pittsburgh, in the County of
Allegheny and State of Pennsylvania, U.S.A., Electrical Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement:-
My invention relates to fuse blocks for electric circuits and has for its object
to provide an improved device of that kind in which the fuse block consists of
two parts one of which is fixed and is provided with circuit terminals, and the
other of which contains the fuse and is removable from the fixed portion of the
block so that a fresh fuse can be readily inserted when desirable.
My invention consists in the special constructional arrangements by means of
which the two parts of the fuse block are secured together so that they can be
separated with a minimum expenditure of time and labour and a maximum
degree of safety.
The drawings filed with the Provisional Specification shew a fuse block con-
structed in accordance with my invention.
Figure 1 is a vertical section.
Figure 2 is a plan partly sectional.
Figure 3 a section on the line 3-3 Figure 1, and
Figure 4 an under plan view shewing the locking portion of the block.
The fixed portion of the block is indicated by the numeral 1 and carries the
spring circuit terminals 2 with which the heads 3 in metallic connection with the
fuse wire make contact when the fuse is in position.
The removable portion of the block 4 has a projecting part 5 which enters an
orifice in the fixed part of the block and is secured therein by means of a screw
clamp 6. The part 4 has a cross channel 7 forming the fuse chamber through
which the fuse wire passes, the ends of the fuse wire being clamped between the

page_text: screw caps 3 and the plugs which are secured in the part 4 of the fuse block. The
fuse chamber 7 has a lateral opening 8 which passes through the portion 5 and
acts as a blow-out opening to permit the escape of the gases formed when the
fuse is vaporized and to assist in blowing out any are which may be established
between the fuse terminal. The fixed portion 1 of the fuse block is provided
with flanges 9 which engage with corresponding flanges 10 on the removable por-
tion 4 of the block and a packing ring 11 of india-rubber or other suitable
material is interposed between the two portions so that the fuse and terminals
will be enclosed in a practically water tight chamber when the two parts of the
block are secured together (see Figures and 3).
The clamping means which I prefer consists of a combined screw and bayonet
catch, the part 5 being provided with two diametrically opposite longitudinal
grooves 12 and 13 and with diagonal or helical grooves 14 and 15 which extend
through nearly the semi-circumference and communicate with the longitudinal
grooves 12 and 13 respectively. 6 is a clamping nut provided with a handle and
having two projections or lugs 16 which engage with the above mentioned
grooves.
The various parts of the fuse block and length of the grooves are so propor-
tioned that when the two parts 1 and 4 are in proper position the lugs 16 on
the clamping nut 6 will be at the inner ends of the grooves 12 and 13 so that
a half turn of the clamping nut will force the removable part 4 of the block
against the fixed portion squeezing the packing ring 11.
It is clear that instead of the special form and of clamping nut shewn provided
with lugs, an ordinary screw nut may be used. The method of securing the fuse
wire in position by means of the terminal screw caps 3 is well known to electrical
engineers and needs no further description.
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 fuse block of the kind described having the fixed portion of the block pro-
vided with an opening through which a projection of the removable portion
extends being clamped by suitable clamping device, and with or without a blow-
out orifice extending through said projection of the removable portion.
2. A fuse block constructed substantially as described with reference to the
accompanying drawing.
Dated the 18th day of Anril 1900
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester, and Birmingham.