Improvements relating to Resistance Frames and the like used for Electrical Purposes.
Year: 1891

page_text: Date of Application, 30th Oct., 1891
Complete Specification Left, 29th July, 1892-Accepted, 8th Oct., 1892
PROVISIONAL SPECIFICATION.
Improvements relating to Resistance Frames and the like used for
Electrical Purposes.
We, CHARLES SCOTT SNELL of Culver Park Saltash Cornwall, Electrical
Engineer, and WOODHOUSE AND RAWSON UNITED LIMITED of 88 Queen
Victoria Street London, Electrical Engineers and Contractors, do hereby declare
the nature of this invention to be as follows:-
The object of this invention is to produce convenient and easily manufactured
resistance frames, and it consists in one case in arranging the rods tubes or other
distance pieces parallel to the coils, in such a manner that the tension on the coils
may be capable of regulation, for instance by means of one tube sliding within
another or equivalent telescopic arrangement, capable of being clamped or other-
wise fixed in any one position, a considerable range of adjustment is possible, or in
place of the telescopic arrangement, a frame or frames on the lazy-tongs principle
may be made use of
For facility in erecting we preferably make use in single frames, of upper and
lower pieces of angle iron, and on the horizontal flange of each piece drill
holes to take cylindrical "shouldered" insulators, which are formed with holes
co-incident with their axes. The holes in the angle irons may be broken through
to the edges thereof thus making a key-hole shaped aperture and admitting of a
section of wire being taken away from the frame or replaced without disturbing
the whole system.
To join any two adjacent sections of wire, their ends are threaded through their
respective insulators and enter corresponding holes in a metal bar, being held there
by suitably arranged screws.
A switch to put in or take out the whole or part of the resistance may be
attached to the frame.
Obviously the same adjustability may be given by a telescopic arrangement of
centre spindle and discs or spiders top and bottom, the resistance being circularly
arranged, and further the whole may be made capable of rotation, and by a suitable
commutator vary the number of coils in the circuit, or a switch may be attached to
the top disc or spider.
In case of cylindrical drum winding of the resistance wire in place of separate
spiral coils, we may support or clamp the drum when wound by a top and bottom
disc of spun or stamped metal (or if preferred some insulating material may be
used) these two ends being held together by a central spindle, either admitting of
revolution of the drum or otherwise as may be desired.
In some cases we may so arrange the resistance wire, that some or all the wire
employed is short circuited by a number of fusible wires or plugs, in such a manner
that upon one or more fuses going, a corresponding amount of the resistance wire
8 put in the circuit.
Where a number of coils are arranged to form parallel rows, the top plate may
be of metal with holes for the insulators, and the coupling pieces may be as
described, the corners of the plate having telescopic distance pieces or their
equivalent, to admit of adjustment. A switch may be arranged in combination
with this system.

page_text: In place of the metal top as above arranged, porcelain or slate may be used and
the insulation dispensed with.
October 29th 1891.
COMPLETE SPECIFICATION.
Improvements relating to Resistance Frames and the like used for
Electrical Purposes.
CHARLES SCOTT SNELL of Culver Park Saltash Cornwall, Electrical Engineer,
and WOODHOUSE & RAWSON UNITED, LIMITED of 88 Queen Victoria Street,
London, Electrical Engineers and Contractors, 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 :-
The object of this invention is to produce convenient and easily manufactured
resistance frames and it consists in one case in arranging the rods, tubes or other
distance pieces parallel to the coils in such a manner that the tension on the coils
may be capable of regulation for instance by means of one tube sliding within
another or equivalent telescopic arrangements, capable of being clamped or other-
wise fixed in any one position a considerable range of adjustment is possible, or in
place of the telescopic arrangement, a frame or frames on the lazy tongs principle
may be made use of.
For facility in erecting, we preferably make use in single frames of upper and
lower pieces of angle iron, and on the horizontal flange of each edge drill holes to
take cylindrical shouldered" insulators, which are formed with holes co-incident
with their axes. The holes in the angle irons may be broken through to the
edges thereof thus making a keyhole shaped aperture and admitting of a section
of wire being taken away from the frame or replaced without disturbing, the whole
'system.
To join any two adjacent sections of wire their ends are threaded through their
respective insulators and enter corresponding holes in a metal bar, being held there
"by suitably arranged screws.
A switch to put in or take out the whole or part of the resistance may 'be
attached to the frame.
Obviously the same adjustability may be given by a telescopic arrangement of
the centre spindle and dises or spiders top and bottom, the resistance being circularly
arranged, and further the whole may be made capable of rotation and by a suitable
commutator vary the number of coils in the circuit or a switch may be attached to
'the top disc or spider.
In case of cylindrical drum winding of the resistance wire in place of separate
spiral coils, we may support or clamp the druin when wound by a top and bottom
disc of spun or stamped metal (or if preferred some insulating material may be
used) these two ends being held together by a central spindle, either admitting of
revolution of the drum or otherwise as may be desired.
In some cases we may so arrange the resistance wire, that some or all of, the
wire employed is short circuited by a number of fusible wires or plugs in such a
mauner that on one or more fuses going a corresponding amount of the resistance
wire is put in the circuit.
Where a number of coils are arranged to form parallel rows, the top plate may
be of metal with holes for the insulators, and the coupling pieces may be as
described, to admit of adjustment. A switch may be arranged, in combination
with this system.

page_text: the insulation dispensed with.
The better to explain our meaning reference is made to the accompanying
drawings in which
Fig. 1 is a front elevation and Fig. 2 a plan of one arrangement.
Figs. 3-6 are details of the same.
Fig. 7 shows the alternative arrangement on the lazy tongs principle.
Fig. 8 shows a general view of the frame and switch.
Figs. 9-10 show telescopic centre spindle arrangement with a commutator and
rotating frame.
Fig. 11 shows switch and fixed frame.
Figs. 12 and 13 show a cylindrical drum wound resistance clamped between spun
or stamped metal discs.
Fig. 14 is a diagram of fuse arrangements for automatically putting in
resistance.
4
Referring to Fig. 1 it will be seen that the distance pieces of the two sides
consist respectively of a rod A working in a tube B, and admitting. of being
clamped by screw C (see Fig. 6 which is a detail of the fastening) thus giving a
large range of adjustment as regards the distance between the upper and lower
members of the frame. It will also be seen that the said members consist of angle
iron, the horizontal flange of each being provided with openings for cylindrical
shouldered insulators (illustrated more clearly by Figs. 3 and 4 and marked D)
these openings may be keyhole shape see É Fig. 2, thereby admitting of the
removal of any section of wire without disturbing the whole frame.
In Figs. 3 and 4 it will be seen that any two adjacent sections of wire are joined
by being threaded through their respective insulators D and being clamped by the
screws F in the metal bar. In Fig. 5 section, and Fig. 6 plan, of the connection
it will be seen that a bar H is used in conjunction with the casing I so that if the
frame is fastened to a wall or its equivalent through the holes J J, the upper
member of the frame may be freely raised or lowered.
In Fig. 7 it is obvious that drawing together the joints KK by the screw L
pushes the upper and lower members of the frame apart. In Fig. 8 it will be seen
that a slate base M may be put below the frame and switch attached to vary the
resistance. In Fig. 9 the centre spindle is telescopic as explained in reference to
Fig. 1 and by putting one end of the resistance wire in connection with the disc,
base and the terminal N, the resistance between that and the other terminal O may
be varied by rotating the whole frame as a contact tongue P bears on the strips Q
and makes the necessary connection. These strips Q as shewn in the inverted
plan Fig. 10 are the equivalent of the metal bar G in Figs. 3 and 4.
Fig. 11 is a plan of the top with switch working on the metal strips, this of
course saves rotating the whole frame. Fig. 12 shows section and Fig. 13 plan, of
a drum wound resistance clamped by the centre spindle between the two spun
discs R, insulating pieces S being inserted at intervals. Fig. 14 shows diagram-
matically the coils of a resistance frame arranged with fuses T so that excess of
current causing one or more fuses to go a corresponding amount of resistance is
automatically inserted in the circuit.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. The construction or combination of the parts of a resistance frame so that
the distance or other pieces which regulate the tension on the spiral coils are
capable of adjustment substantially as herein described and illustrated in the
accompanying drawings.
2. The combination in a resistance frame of adjustable distance pieces cylindrical
shouldered insulated "keyhole" apertures and connecting metal bars substantially
as herein described and illustrated in the accompanying drawings.

page_text: 3. The combination in a resistance frame of one or more vertical adjustable
distance pieces, a centre spindle admitting of rotation of the frame and a contact
tongue or its equivalent substantially as herein described and illustrated in the
accompanying drawings.
4. The combination with a drum wound resistance coil of spun or stamped
metal clamping discs substantially as herein described and illustrated in the
accompanying drawings.
5. The combination with a resistance frame of fuses so arranged as to short
circuit the coils and thereby upon the fuses "blowing" to cause automatically an
increased resistance to be inserted in the circuit.
A
1000
C. SCOTT SNELL.
WOODHOUSE & RAWSON UNITED, LIMITED
A. L. Foley, Secretary.