Improvements in Switches for Electric Circuits.
Year: 1898

page_text: Date of Application, 19th July, 1898
Complete Specification Left, 18th Apr., 1899-Accepted, 20th May, 1899
Pittsburg, U.S.A., and GILBERT WRIGHT, of Wilkinsburg, U.S.A., Electrical
Engineers.]
Improvements in Switches for Electric Circuits.
I, REGINALD BELFIELD, of 32, Victoria Street, Westminster, in the County of
London, England, Electrician, do hereby declare the nature of this invention
to be as follows:-
My invention relates to switches for electric circuits and has for its object to
provide a switch for varying the active length of an electrical conductor. Accord-
ing to my invention I do this by dividing the entire conductor into two parts,
one of said parts being divided into a number of units which are cut in onc
by one, and when all of the said units have been cut in, the undivided portion
of the conductor is, by means of an auxiliary switch, substituted for the divided
portion to which it is approximately equal and then the several units of the
divided portion can be cut in again in succession until the entire conductor is
in circuit. The active length of the conductor can be gradually reduced by
cutting out successive lengths of the divided portion and when the said portion
has been thus cut out re-inserting the said portion and cutting out the undivided
portion of the conductor. By substituting in this manner an undivided portion
of the resistance or coil for a similar divided resistance or coil I am enabled to
vary the resistance or length of the windings within very wide limits, and at
the same time the switch is made with a smaller number of terminals and fewer
connections are required than would be the case where the entire resistance or
coil is divided into units.
In the apparatus I have devised for effecting the above changes in the circuit
the auxiliary switch operates automatically to substitute one portion of the con-
ductor for the other when necessary said apparatus is illustrated in the accom-
panying drawings as applied to transformers for use with two phase currents,
but my invention is not necessarily restricted to such use.
Figure 1 is a frent elevation with a portion of the casing removed shewing my
improved switch.
Figure 1 is a detail view of a modified form of contact device.
Figure 2 is a vertical section, certain of the parts being shewn in elevation.
Figure 3 is an elevation and
Figure 4 a side view of the portion of the apparatus shewn in dotted lines in
Figure 1.
Figure 5 is an elevation and
Figure 6 a side view partly sectional of an auxiliary switch.
13
"
10
11

page_text: Figure 11 is a diagram shewing how the switch is connected in circuit with
the transformer windings.
Figure 12 is a diagram illustrating a modified form of switch.
Referring now to Figures 1 to 10, 1 is the middle portion of the combined
supporting frame and casing. 2 and 2 being end plates secured to the portion 1
and enclosing the operating parts of the switch. 3 and 3" are circular vertical
plates of insulating material bolted to lugs 3b and 3 projecting inwardly from
the frame 1. The plate 3 has an annular series of cylindrical contact pieces 4,
the fastening bolts of which extend through the supporting plate 3 and are
provided with connectors 5 for the conducting wires. The two adjacent parts t
at the top are connected by a conducting segment 6 so as to form a single broad
contact as shewn. Small insulated cylinders 7 are arranged between the contact 4,
but are not connected in any way to the circuit being merely dummies to prevent
the contact piece of the switch arm from dropping between the contacts 4.
The contact arm 8 is supported by a shaft 9 which extends through an opening
in the centre of the plate 3, and is journalled in a suitable bearing box 10 which
also extends through the supporting plate and is bolted or otherwise fastened
thereto. An auxiliary arm 8b is also supported by the shaft 9. The arms are
separated by a washer 8 but are not independently movable. The auxiliary
arm has a strip 11 fastened to its outer end which is bemt at substantially right
angles to said arm and is provided with a laterally extending head 12, such
head having at or near its ends, contact pieces 13. These contact pieces 13 are
electrically connected with the contact arm 8 and with each other and make
initial and final contact with the cylindrical surfaces of the contact pieces 4 and
serve to take any arcs which may be formed as the arm 8 is moved from one to
another of the contact pieces 4.
The plate 3 is provided with parts 4", 5", 6" and 7" similar to those above
described with reference to the plate 3; also contact arms 8", 8d with appur-
tenances 8, 11, 12, and contacts 13" mounted on the plate 3", are provided
similar in construction and operation to those just described.
In Figure 1 is shewn a modification in which the head 12 fastened to the
end of extension 11 is of non-conducting material and the supplemental con-
tacts 13b mounted thereon are spaced apart a sufficient distance to simultaneously
make contact with adjacent contact pieces 4. These supplemental contacts 13
aro electrically connected with each other through a resistance coil 53, and sub-
stantially the middle point of the latter is connected to the extension 11'.
By this means the current is reduced sufficiently to prevent destructive arcing
between the supplemental contacts 13 and the contact pieces 4.
Each of the contact arms 8 and 8 project beyond its shaft in a direction
opposite to its contact end a considerable distance, the former being provided
with a roller 14, and the latter with a corresponding roller 14".
The inner end of the shaft 9 is provided with a head 15 to which is fastened,
by means of screws or otherwise, a plate 16 of insulating material. A similar
plate 17 having a laterally projecting stud 18 is riveted or otherwise securely
fastened to the plate 16. A ratchet wheel 19 is mounted rigidly upon the stud 18
and has pivoted to its outer face, near the edge, a stop piece 20, see Figures 3
and S. The adjacent plate 17 is cut away at 21 to provide space for the movement
of the stop piece 20, and in this space is mounted a flat spring 22, the free
end of which bears against the inner edge of the stop piece 20, so as to retain
such stop piece in any position to which it may be moved. A head 15", plates 16ª
and 17, a stud projecting from the latter but not shewn, a ratchet wheel 19ª, a
stop piece 20°, and a spring therefor of like construction to the parts above
mentioned are correspondingly located with reference to the plate 3 and its
contact pieces.
Located centrally with reference to the plates 3 and 3 is an operating lever
which is journalled upon the hubs of the two ratchet wheels 19 and 19. This
lever comprises two principal parts 24 and 25, the main part 24 which is jour-

page_text: nalled upon the hubs of the ratchet wheels 19 and 19ª being provided with a
socket extending some distance downward from its upper end, and in this socket
is located the lower end of the part 25. This part 25 projects through an oblong
opening 26 in the top of the frame or casing, and, just above such opening, is
provided with a pointer 27 and a handle 28 (see Figure 7). Pivoted to the main
portion 24 of the lever, a short distance above the ratchet wheels, are two double-
ended pawls, 29 and 29", each of which is in the same plane with the corresponding
ratchet wheel. The pawls 29 and 29" are respectively provided with laterally
projecting pins 30 and 30" near their lower edges and midway of their ends.
The upper end of the socket portion 24 of the lever is provided with pairs of
notches 31 and 31", and extending through the upper portion 25 of the lever
in position to rest in one or the other pair of notches is a long pin 2, (see
Figures 8 and 10). The ends of this pin 32 are connected by coiled springs 33
and 33 with the corresponding laterally projecting pins 30 and 30° on the lower
edges of the pawls 29 and 29.
In order to permit the upper portion 25 of the lever to be given a partial
rotation so as to move the pin 32 from one pair of notches to the other, it is
provided with a pin 34 which projects laterally through an opening 35 in the
side of the socket (see Figure 9). This opening 35 is of such size that, while it
will permit of the necessary degree of rotation of the upper portion of the lever,
it will also prevent the withdrawal of such lever portion from its socket. The
lever 23 projects downward from its middle or bearing portion to a point near
the bottom of the frame and has pivoted to its lower end a double ended dog 36,
the lower end being bifurcated in order to receive this dog. The dog is provided
midway of its ends and at its lower edge with a pin 37 which projects laterally
from both sides, and the lever, at some distance above the dog is provided with a
similar pin 38. Coiled springs 39 and 39 connect the corresponding ends of
these pins, as shewn. A plate or bar 40 having a toothed or notched upper edge
is located in the bottom of the frame or casing, the teeth being arranged in the
are of a circle and in the plane of the path of movement of the dog 36 as the
lever is moved back and forth on its bearings. This toothed plate is also provided
on one side with two lugs or projections 40" extending upward a sufficient
distance to be in the path of movement of one end of the pin 37.
41 and 41 are holding pawls pivoted at the ends of the plate 40 and adapted
to engage with the ratchet wheels 19 and 19" respectively, said pawls are con-
nected together by a spring 44 having looks 45 engaging with the pins 43 and
which passes through an orifice 46 in the lever 24, so as to permit the latter to
move freely (see Figures 2, 3 and 4).
47 is an auxiliary switch arm pivoted at the outside of the plate 3, its pivot
pin being provided at the back with a wire connector. The said arm 47 has
two lugs 48 and 49 projecting below its pivet, one of which is always in position
to be engaged by the roller 14 on the lewer end of the contact arm 8, and is
adapted to engage in its extreme positions with one or other of two stationary
contact pieces 50 and 51 secured to the plate 3 (see Figures 5, and 6, and 11).
The plate 3 is provided with a switch arm 47° having projections 48 and 49
and with contact pieces 50 and 51ª similar to those above described for the
plate 3.
Figure 11 is a diagram shewing the two parts of the switch separated for
convenience of illustration with the primary windings of two transformers 52
and 52, so that by the operation of the switch the length of the primary winding
of each transformer can be varied step by step. The transformers are intendeil
for the transformation of two-phase currents the line wires for one phase being
connected at L L and for the other phase at Lª LA.
The operation of the apparatus is as follows:-
Assuming that the parts are in the positions indicated in Figures 3. 6, 7, and 11.
the lever 24 being at the extreme left position and the part 25 tarned, as indicated´
in Figure 7, so as to lower the electromotive force, if the handle be moved from

page_text: left to right as far as the opening in the top of the casing will permit, the
pawl 29 will move the ratchet wheel 19 one notch and with it the corresponding
contact arm 8". With the parts in the position just indicated, it will be observed
by referring to Figure 11 that the circuit through the switch arm 8" at the right,
the contact piece on which it rests and the auxiliary switch 47", 51", includes the
portion of the primary winding of transformer 52. When the arm 8" is moved,
by means of the lever 23, the pawl 29" and ratchet 19", on to the next stationary
contact, this same portion of the primary winding of the transformer 52" will
be in circuit and also one division of the portion b It will be observed that in
moving the handle and its lever from left to right, a complete stroke is necessary
before returning it to the original position, for the reason that the dog 36 drags
over the toothed edge of the plate or bar 40, and is held in such position by the
springs 39 and 39", and that if any attempt is made to reverse the movement of
the lever before the complete stroke is made, the dog will catch upon a tooth
and stop the motion of the lever. When, however, the lever is moved completely
to the end of the slot in the top of the casing, the pin 37 will strike against the
lug 40" at the left and trip the dog, thus carrying the springs 39 and 39 to the
other side of the centre where they will hold the dog in the tripped position.
The same function will be effected when the movement of the lever is made in
the other direction until the end of the stroke, when the lug 40" at the right hand
side will again trip the dog into the position shewn in Figures 1 and 3.
The movement of the lever from right to left will carry with it the correspond-
ing ratchet wheel 19 and the contact arm 8 by reason of the pawl 29 which engages
with the adjacent tooth of the ratchet wheel and thus cut into circuit a division
of the portion of the primary of the transformer 52, in the same manner as has
been described in connection with the transformer 52. This back and forth
movement is repeated and the contact arms are moved step by step in opposite.
directions to cut into circuit, one after another, the divisions of the portions a²
and of the transformer-primaries until the contact arms have reached the last
stationary contact pieces before coming upon the long contacts 6 and G at the
top of the switch. When these points are reached, the entire divisions a² and
of the primary windings are in circuit. When the contact arms are moved the
next step or notch, the rollers on their lower ends engage with the outermost lugs
projecting from the auxiliary switch arms and move the arms from their stationary
contacts. The circuits will then include the portions a, a and b, b₁ of the primary
windings and the portions and 2 will be cut out. The next movement of one
notch or step throws the auxiliary switches over to their other stationary contacts,
as is shewn in Figure 1.
The operation may be continued the same as has already been described, the
portions and 2 of the transformer primary windings being cut step by step
into circuit as the contact arms are moved from contact to contact in opposite
directions around the two discs or plates. When these arms have been moved
until they come to the last contacts before reaching the long contacts at the top,
the entire winding of each transformer will be included in circuit and it will be
impossible to continue the operation of the parts from that point, for the reason
that the stop pieces 20 and 20" will respectively engage with the pins 53 and 53ª
projecting from the sides of the holding pawls. If it is now desired to raise the
electromotive force, the handle 25 is given a partial rotation which carries with
it the pin 32 and the springs 33 and 33" connecting the ends of the same with
the pins 30 and 30% on the lower side of the pawls 29 and 29 until the pin 32
drops into the other pair of notches 31 and 31 in the top of the socket. This
position of the pin brings the pulling action of the springs to bear at such an angle
that the two pawls will be tripped or reversed as is shewn in Figure 8. When
in this position the movement of the operating handle will move the ratchet
wheels and contact arms step by step from contact to contact in the same manner
as has already been described and gradually cut out of circuit the portions a²
and of the primary windings, until one revolution of the armis has been made,.

page_text: when the rollers on the lower ends of the arms will engage with the projections
on the auxiliary switch arms and throw them into contact with the other stationary
contact pins or pieces, thus cutting into circuit the portions a² and 2 and
simultaneously cutting out of circuit the portions a¹ and 6'. The operation may
then be continued until the portions and are entirely cut out, leaving only
the portions a and b in circuit. It will be readily understood that this entire
operation need not be carried out, since any degree of variation of the electro-
motive force either up or down may be effected by a proper manipulation of the
operating lever.
It should be stated that when the main and auxiliary switch contact arms are
in the positions indicated in Figure 11, and the operating parts are as indicated
in Figure 3, the stop pieces are so located with referance to the stop pins pro-
jecting from the holding pawls that the forward end of the stop pieces will clear
such pins during the first rotation; but that in passing the pins and making
the second rotation, these stop pieces will be turned on their pivots by such pins,
as will be understood, so that when the second rotation is completed, the ends
which project beyond the line of the pins will come into contact therewith and
stop the ratchet wheels and contact arms.
It will be understood that the portion of each transformer winding that is
always in circuit may have any length desired, it being desirable, however, that
the two portions which replace each other should be approximately of the same
length.
In Figure 12, I illustrate another form of switch for varying the length of the
transformer winding in a similar manner to that above described. The switch
is shewn in plan and has two sets of stationary contacts 101 to 11 and 101"
116", each set being arranged substantially in a semi-circle. The contacts 101
to 117 are connected to a series of leads from a portion of the primary winding
of the transformer 52, and the contacts 101" to 116" are connected to corre-
sponding leads from a portion of the primary winding of the transformer 52ª.
The number of sub-divisions of each of these portions and which is included
in the main circuit is determined by the position of a pivoted arm E having
contacts e and at its respective ends which close the circuit between the
stationary contacts and corresponding concentrically located semi-annular strips (2
and The pivoted arm E is provided near its respective ends with pins et
and each of which is so located as to engage with one of the projections f on
a pair of auxiliary switch arms F and F so as to throw said arms simultaneously
from the respective co-operating stationary contacts f¹ and f² to the contacts f³
and f, or rire mersa, according to the direction of movement of the arm É.
g and are two stationary contact pieces respectively connected electrically with
the contact pieces e3 and 101 and located in the path of movement of a contact
arm G. which is mechanically connected to and movable with the arm E. The
arm E is provided with a projection H. from which depends a stop piece (not
shewn) which engages with a stop pin when the arm E has made a complete
rotation.
Assuming that the auxiliary switch arms F and F are in the positions indicated
in the drawing and that the switch arm E is to be moved in the direction of the
hands of a clock, the operation is as follows:-
In the position shewn, the first subdivision of each of the sections a² and 2 of
the primary windings is cut out, as will be readily seen by tracing the circuits
from the conductors designated L L and L", L" through the half rings 2 and 3,
movable contacts e and and stationary contacts 115 and 115, and the corre-
sponding circuit wires. If the arm E be moved another step, it will first cub
but another subdivision of the primary of the transformer 52", and then another
subdivision of the primary of the transformer 52, and so on, until very nearly
a half revolution of the arm E has been effected when the pin e and will
respectively come into contact with the outermost projections f on the auxiliary

page_text: switch arms F and F and throw them out of engagement with the corresponding
contacts and f
A continuation of this movement of the arm E will cause the pins et ande to
move the arms F and F into contact with the stationary contact pieces f* and f'.
This, as will be seen, will so change the circuits that when the contacts e and e
engage with the pieces 116 and 116, the subdivided portions a² and 2 of the
transformer primary winding will be again in circuit and the divisions a¹ and '6¹
will be cut out of circuit.
It will be observed that the arrangement of the sets of stationary contacts with
reference to each other and with reference to the contacts è and e' is such that
both circuits are never broken at the same time. When the contact,e is passing
and thus
from contact 100 to contact 116", the arm G bridges the strip
At that
closing the circuit for one phase through the strip and contact 100".
time contact e¹ is on contact 117 and the circuit for the other phase is through
that contact and strip e³.
If the rotation of the arm. E is continued in the same direction until the
stationary contacts are all passed a second time, the divisions a², a¹ and 72, 1
of the transformer primary windings will be entirely cut out. Further move-
ment of the arm E is prevented by the engagement of the stop piece on the pro-
jection Hwith the pin h. A reverse movement of the arm E will serve to reinsert
the subdivided portions of the windings step by step until a half rotation is
effected, when the auxiliary switches will be thrown in the other direction to
cut out these subdivided portions and at the same time cut in the next portions.
Another half rotation of the arm will serve to again cut in the subdivided portions
of the transformer windings, step by step, until the entire primary windings are
in circuit.
This replacing of a subdivided portion by a corresponding length which is not
subdivided is extremely advantageous by reason of the fact that a much smaller
and less complicated switching apparatus may be employed, since the number
of stationary contact pieces is only one-half what it would be if the entire portion
of the transformer winding cut out should be cut out step by step.
I desire it to be understood that my invention is in no wise limited to the
particular apparatus illustrated and described, since any apparatus which may
be devised or employed for practising the method may be used without departing
from the spirit and scope of the invention.
I desire it to be also understood that my invention is not limited to any specific
kinds of
number or kind of circuits, either as regards phases of current or
apparatus producing or utilizing the same."
Dated tho 10th Ja of Tu 1908
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C.,
Patent Agents for the Applicant.
Improvements in Switches for Electric Circuits.
I, REGINALD BELFIELD, of 32, Victoria Street, Westminster, in the County of
London, England, 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:-
My invention relates to switches for electric circuits and has for its object to
provide a switch for varying the active length of an electrical conductor.
Accord-

page_text: ing to my invention I do this by dividing the entire conductor into two parts,
one of said parts being divided into a number of units which are cut in one
by one, and when all of the said units have been cut in, the undivided portion
of the conductor is, by means of an auxiliary switch, substituted for the divided
portion to which it is approximately equal and then the several units of the
divided portion can be cut in again in succession until the entire conductor is
in circuit. The active length of the conductor can be gradually reduced by
cutting out successive lengths of the divided portion and when the said portion
has been thus cut out re-inserting the said portion and cutting out the undivided
portion of the conductor. By substituting in this manner an undivided portion
of the resistance or coil for a similar divided resistance or coil, or vice versa, I am
enabled to vary the resistance or length of the windings within very wide limits,
and at the same time the switch is made with a smaller number of terminals
and fewer connections are required than would be the case where the entire
resistance or coil is divided into units.
In my improved apparatus the substitution of an undivided portion of the
conductor for a divided portion or rice versa is effected by an auxiliary switch
which is automatically operated every time the main switch arm passes the last
of the set of contacts to which the several sections of the divided portion of the
conductor are connected. The movement of the main switch arm is then repeated
passing over the set of contacts as many times as may be necessary to complete
the whole series of changes which can be made in the length of the conductor.
In the accompanying drawings the apparatus is illustrated as applied to the
primary windings of transformers for two phase currents but my invention is
not necessarily restricted to such use.
Figure 1 is a front elevation with a portion of the casing removed shewing my
improved switch.
Figure is a detail view of a modified form of contact device.
Figure 2 is a vertical section, certain of the parts being shewn in elevation.
Figure 3 is an elevation and
Figure 4a side view of the portion of the apparatus shewn in dotted lines in
Figure 1.
Figure 5 is an elevation and
Figura 6 a side view partly sectional of an auxiliary switch.
Figures 7 to 10 are detail views hereinafter referred to.
Figure 11 is a diagram shewing how the switch is connected in circuit with
the transformer windings.
Figure 12 is a diagram illustrating a modified form of switch.
Referring now to Figures 1 to 10, 1 is the middle portion of the combined
supporting frame and casing. 2 and 2 being end plates secured to the portion !
and enclosing the operating parts of the switch. 3 and 3 are circular vertical
plates of insulating material bolted to lugs 3 and 3 projecting inwardly from
the frame 1. The plate 3 has an annular series of cylindrical contact pieces 4,
the fastening bolts of which extend through the supporting plate 3 and are
provided with connectors 5 for the conducting wires. The two adjacent parts
at the top are connected by a conducting segment 6 so as to form a single broad
contact as shewn. Small insulated cylinders 7 are arranged between the contact 4,
but are not connected in any way to the circuit being merely dummies to prevent
the contact piece of the switch arm from dropping between the contacts 4.
The contact arm S is supported by a shaft 9 which extends through an opening
in the centre of the plate 3, and is journalled in a suitable bearing box 10 which
also extends through the supporting plate and is bolted or otherwise fastened
thereto. An auxiliary arm 8b is also supported by the shaft 9. The arms are
separated by a washer 8 but are not independently movable. The auxiliary
arm has a strip 11 fastened to its outer end which is bent at substantially right
angles to said arm, and is provided with a laterally extending head 12, such
head having at or near its ends, contact pieces 13. These contact pieces 13 are

page_text: electrically connected with the contact arm $ and with each other and make
initial and final contact with the cylindrical surfaces of the contact pieces 4 and
serve to take any ares which may be formed as the arm 8 is moved from one to
another of the contact pieces 4.
The plate is provided with parts 4", 5", 6" and 7" similar to those above
described with reference to the plate 3; also contact arms 8", 8d with appur-
tenances 8, 11, 12, and contacts 13" mounted on the plate 3", are provided
similar in construction and operation to those just described.
In Figure 1ª is shewn a modification in which the head 12 fastened to the
end of extension 11' is of non-conducting material and the supplemental con-
tacts 13 mounted thereon are spaced apart a sufficient distance to simultaneously
make contact with adjacent contact pieces, 4. These supplemental contacts 13
are electrically connected with each other through a resistance coil 53, and sub-
stantially the middle point of the latter is connected to the extension 11b.
By this means the current is reduced sufficiently to prevent destructive arcing
between the supplemental contacts 13 and the contact pieces 4.
Each of the contact arms 8 and 8" project beyond its shaft in a direction
opposite to its contact end a considerable distance, the former being provided
with a roller 14, and the latter with a corresponding roller 14".
The inner end of the shaft 9 is provided with a head 15 to which is fastened,
by means of screws or otherwise, a plate 16 of insulating material. A similar
plate 17 having a laterally projecting stud 18 is iveted or otherwise securely
fastened to the plate 16. A ratchet wheel 19 is mounted rigidly upon the stud 18
and has pivoted to its outer face, near the edge, a stop piece 20, see Figures B
and S. The adjacent plate 17 is cut away at 21 to provide space for the movement
of the stop piece 20, and in this space is mounted a flat soring 22, the free
end of which bears against the inner edge of the stop piece 20, so as to retain
such stop piece in any position to which it may be moved. A head 15", plates 16"
and 17, a stud projecting from the latter but not shewn, a ratchet wheel 19", a
stop piece 20", and a spring therefor of like construction to the parts above
mentioned are correspondingly located with reference to the plate * and its
contact pieces.
Located centrally with reference to the plates 3 and 3 is an operating lever
which is journaler upon the hubs of the two ratchet wheels 19 and 19 This
lever comprises two principal parts 24 and 25, the main part 24 which is jour-
nalled upon the hubs of the ratchet wheels 19 and 19 being provided with a
socket extending some distance downward from its upper end, and in this socket
is located the lower end of the part 25. This part 25 projects through an oblong
opening 26 in the top of the frame or casing, and, just above such opening, i
provided with a pointer 27 and a handle 28 (see Figure 7). Pivoted to the main
portion 24 of the lever, a short distance above the ratchet wheels, are two double-
ended pawls, 29 and 29ª, each of which is in the same plane with the corresponding
ratchet wheel. The pawls 29 and 29 are respectively provided with laterally
projecting pins 30 and 30 near their lower edges and midway of their ends.
The upper end of the socket portion 24 of the lever is provided with pairs of
notches and 31 and extending through the upper portion 25 of the lever
in position to rest in one or the other pair of notches is a long pin 32, (see
Figures and 10). The ends of this pin 32 are connected by coiled springs 33
and 33 with the corresponding laterally projecting pins 30 and 30 on the lower
edges of the pawls 29 and 29.
In order to permit the upper portion 25 of the lever to be given a partial
rotation so as to move the pin 32 from one pair of notches to the other, it is
provided with a pin 34 which projects laterally through an opening 35 in the
side of the socket (see Figure 9). This opening 35 is of such size that, while it
will permit of the necessary degree of rotation of the upper portion of the lever,
i will also prevent the withdrawal of such lever portion from its socket. The
lever 24 projects downward from its middle or bearing portion to a point near

page_text: the bottom of the frame and has pivoted to its lower end a double-ended dog 36,
the lower end being bifurcated in order to receive this dog. The dog is provided
midway of its ends and at its lower edge with a pin 37 which projects laterally
from both sides, and the lever at some distance above the dog is provided with a
similar pin 38. Coiled springs 39 and 39 connect the corresponding ends of
these pins, as shewn. A plate or bar 40 having a toothed or notched upper edge
is located in the bottom of the frame or casing, the teeth being arranged in the
arc of a circle and in the plane of the path of movement of the dog 36 as the
lever is moved back and forth on its bearings. This toothed plate is also provided
on one side with two lugs or projections 40" extending upward a sufficient
distance to be in the path of movement of one end of the pin 37.
41 and 41" are holding pawls pivoted at the ends of the plate 40 and provided
with rollers 42, 42" adapted to engage with the ratchet wheels 19 and 19" respec-
tively, said pawls are connected together by a spring 44 having hooks 45 engaging
with the pins 43 and which passes through an orifice 46 in the lever 24 so as to
permit the latter to move freely (see Figures 2, 3, and 4).
47 is an auxiliary switch arm pivoted at the outside of the plate 3, its pivot
pin being provided at the back with a wire connector. The said arm 47 has
two lugs 48 and 49 projecting below its pivot, one of which is always in position
to be engaged by the roller 14 on the lower end of the contact arm 8, and is
adapted to engage in its extreme positions with one or other of two stationary
contact pieces 50 and 51 secured to the plate 3 (see Figures 5, and 6, and 11).
The plate 3 is provided with a switch arm 47" having projections 48 and 49"
and with contact pieces 50" and 51" similar to those above described for the
plate 3.
Figure 11 is a diagram shewing the two parts of the switch separated for
convenience of illustration with the primary windings of two transformers 52
and 52", so that by the operation of the switch the length of the primary winding
of each transformer can be varied step by step. The transformers are intended
for the transformation of two-phase currents the line wires for one phase being
connected at L L, and for the other phase at L* L*.
The operation of the apparatus is as follows:-
Assuming that the parts are in the positions indicated in Figures 3, 6, 7, and 11,
the lever 24 being at the extreme left position and the part 25 turned, as indicated
in Figure 7, so as to lower the electromotive forec, if the handle be moved from
left to right, as far as the opening in the top of the casing will permit, the
pawl 29" will move the ratchet wheel 19" one notch and with it the corresponding
contact arm 8". With the parts in the position just indicated, it will be observed
by referring to Figure 11 that the circuit through the switch arm 8 at the right,
the contact piece on which it rests and the auxiliary switch 47, 51", includes the
portion 6 of the primary winding of transformer 52. When the arm 8" is moved,
by means of the lever 25, the pawl 29" and ratchet 19ª, on to the next stationary
contact, this same portion of the primary winding of the transformer 52" will
be in circuit, and also one division of the portion 62. It will be observed that in
moving the handle and its lever from left to right, a complete stroke is necessary
before returning it to its original position, for the reason that the dog 36 drags
over the toothed edge of the plate or bar 40, and is held in such position, by the
springs 39 and 39%, and that if any attempt is made to reverse the movement of
the lever before the complete stroke is made, the dog will catch upon a tooth
O and stop the motion of the lever. When, however, the lever is moved completely
to the end of the slot in the top of the casing, the pin 37 will strike against the
lug 40 at the left and trip the dog, thus carrying the springs 39 and 39 to the
other side of the centre where they will hold the dog in the tripped position.
The same function will be effected when the movement of the lever is made in
5 the other direction until the end of the stroke, when the lug 40 at the right hand
side will again trip the dog into the position shewn in Figures 1 and 3.

page_text: The movement of the lever from right to left will carry with it the correspond-
ing ratchet wheel 19 and the contact arm 8 by reason or the pawl 29 which engages
with the adjacent tooth of the ratchet wheel and tous cut into circuit a division
of the portion at of the primary of the transformer 52, in the same manner as has
been described in connection with the transformer 52". This back and forth
movement is repeated and the contact arms are moved step by step in opposite
directions to cut into circuit, one after another, the divisions of the portions a
and 62 of the transformer primaries until the contact arms have reached the last
stationary contact pieces before coming upon the long contacts 6 and 6" at the
top of the switch. When these points are reached, the entire divisions a and b
of the primary windings are in circuit. When the contact arms are moved the
next step or notch, the rollers on their lower ends engage, with the outermost-lugs
projecting from the auxiliary switch arms and move the arms from their stationary
contacts. The circuits will then include the portions a, a and b, b¹ of the primary
windings and the portions a² and 62 will be cut out. The next movement of one
notch or step throws the auxiliary switches over to their other stationary contacts,
as is shewn in Figure 1.
The operation may be continued the same as has already been described, the
portions a and 62 of the transformer primary windings being cut step by step
into circuit as the contact arms are moved from contact to contact in opposite
directions around the two discs or plates. When these arms have been moved
until they come to the last contacts before reaching the long contacts at the top,
the entire winding of each transformer will be included in circuit and it will be
impossible to continue the operation of the parts from that point, for the reason
that the stop pieces 20 and 20" will respectively engage with the pins 53 and 53"
projecting from the sides of the holding pawls. If it is now desired to raise the
electromotive force, the handle 28 is given a partial rotation which carries with
it the pin 32 and the springs 33 and 33" connecting the ends of the same wit
the pins 30 and 30" on the lower side of the pawls 29 and 29" until the pin 32
drops into the other pair of notches 31 and 31" in the top of the socket. This
position of the pin brings the pulling action of the springs to bear at such an angle
that the two pawls will be tripped or reversed as is shewn in Figure 8. When
in this position the movement of the operating handle will move the ratchet
wheels and contact arms step by step from contact to contact in the same manner
as has already been described and gradually cut out of circuit the portions a²
and 6 of the primary windings, until one revolution of the arms has been made,
when the rollers on the lower ends of the arms will engage with the projections
on the auxiliary switch arms and throw them into contact with the other stationary
contact pins or pieces, thus cutting into circuit the portions a² and 62 and
simultaneously cutting out of circuit the portions a¹ and b¹. The operation may
then be continued until the portions a² and 62 are entirely cut out, leaving only
the portions a and b in circuit. It will be readily understood that this entire
operation need not be carried out, since any degree of variation of the electro-
motive force either up or down may be effected by a proper manipulation of the
operating lever.
It should be stated that when the main and auxiliary switch contact arms are
in the positions indicated in Figure 11, and the operating parts are as indicated
in Figure 3, the stop pieces are so located with reference to the stop pins pro-
jecting from the holding pawls that the forward end of the stop pieces will clear
such pins during the first rotation; but that in passing the pins and making
the second rotation, these stop pieces will be turned on their pivots by such pins,
às will be understood, so that when the second rotation is completed, the ends
which project beyond the line of the pins will come into contact therewith and
ston the ratchet wheels and contact arms.
It will be understood that the portion of each transformer winding that is
always in circuit may have any length desired, it being desirable, however, that

page_text: the two portions which replace each other should be approximately of the same.
length..
In Figure 12, I illustrate another form of switch for varying the length of the
transformer winding in a similar manner to that above described. The switch
is shewn in plan and has two sets of stationary contacts 101 to 117 and 101" to
116", each et being arranged substantially in a semi-circle. The contacts 101
to 117 are connected to a series of leads from a portion of the primary winding
of the transformer 52, and the contacts 101" to 116" are connected to corre-
sponding leads from a portion 2 of the primary winding of the transformer 52".
The number of sub-divisions of each of these portions 2 and 2 which is included
in the main circuit is determined by the position of a pivoted arm having
contacts and e¹ at its respective ends which close the circuit between the
stationary contacts and corresponding concentrically located semi-annular strips
and e. The pivoted arm E is provided near its respective ends with pins
and each of which is so located as to engage with one of the projections f on
a pair of auxiliary switch arms F and F¹ so as to throw said arms simultaneously
from the respective co-operating stationary contacts f¹ and f2 to the contacts f
and f, or vice versa, according to the direction of movement of the arm E
g and glare two stationary contact pieces respectively connected electrically with
the contact pieces e3 and 101 and located in the path of movement of a contact
arm G, which is mechanically connected to and moveable with the arm E. The
arm E is provided with a projection H from which depends a stop piece (not
shewn) which engages with a stop pin h when the arm E has made a complete
rotation.
Assuming that the auxiliary switch arms F and F are in the position indicated
in the drawing and that the switch arm E is to be moved in the direction of the
hands of a clock, the operation is as follows:-
In the position shewn, the first subdivision of each of the sections ² and 12 of
the primary windings is cut out, as will be readily seen by tracing the circuits
from the conductors designated L L and L" L" through the half rings and e',
movable contacts e and c and stationary contacts 115 and 115", and the corre-
sponding circuit wires. If the arm E be moved another step, it will first cut
out another subdivision of the primary of the transformer 52", and then another
subdivision of the primary of the transformer 52, and so on, until very nearly
a half revolution of the arm E has been effected when the pin, et, and e³, will
respectively come into contact with the outermost projections f on the auxiliary
switch arms F and F and throw them out of engagement with the corresponding
contacts and f³.
A continuation of this movement of the arm E will cause the pins and to
move the arms F1 and F into contact with the stationary contact pieces f* and f':
This, as will be seen, will so change the circuits that when the contacts e and e¹
engage with the pieces 116" and 116, the subdivided portions and 2 of the
transformer primary winding will be again in circuit and the divisions a¹ and ¿¹
will be cut out of circuit.
It will be observed that the arrangement of the sets of stationary contacts with
reference to each other and with reference to the contacts e and e¹ is such that
both circuits are never broken at the same time. When the contact e is passing
from contact 100 to contact 116, the arm G bridges the strip and thus
closing the circuit for one phase through the strip and contact 100°. At that
time contact e¹ is on contact 117 and the circuit for the other phase is through
that contact and strip e³.
If the rotation of the arm E is continued in the same direction until the
stationary contacts are all passed a second time, the divisions a², a¹, and 6º,
of the transformer primary windings will be entirely cut out. Further move-
ment of the arm E is prevented by the engagement of the stop piece on the pro-
jection by the pin h. A reverse movement of the arm E will serve to reinsert
the subdivided portions of the windings step by step until a half rotation is

page_text: effected, when the auxiliary switches will be thrown in the other direction to
cut out these subdivided portions and at the same time cut in the next portions.
Another half rotation of the arm will serve to again cut in the subdivided portions
of the transformer windings, step by step, until the entire primary windings are
in circuit.
I desire it to be also understood that my invention is not limited to any specific
number or kind of circuits, either as regards phases of current or kinds of
apparatus producing or utnising the same.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, as communicated to
me by my foreign correspondents, I declare that what
claim is: :-
1. A switch of the kind described in which the substitution of an undivided
portion of the conductor for a divided portion thereof, or cice versa, is effected by
an auxiliary switch which is automatically operated when the main switch arm
passes the last of the set of contacts to which the several sections of the divided
portion of the conductor are connected, further changes in the length of the
conductor being caused by the switch again traversing the same set of contacts,
substantially as described.
2. A duplicate regulating switch of the kind described, for varying the active
length of two dependent or independent circuits, both parts of the switch being
actuated by the same handle, substantially as described.
3. In an electric switch a device for preventing the reversal of the movement
of the actuating lever until said lever has completed its stroke, substantially s
described with reference to Figure 3 of the accompanying drawings.
4. In an electric switch having a contact arm carried by a ratchet wheel the
arrangement for varying the direction of movement of said ratchet wheel by
rotating the operating lever thereof on its longitudinal axis, substantially as
described with reference to Figures 3, 4, 8, 9 and 10 of the accompanying
drawings.
5. Regulating switches for one or for two circuits, constructed and operating
substantially as described with reference to Figure 1 to H, or to Figure 12, of
the accompanying drawings.
Dated the 18th day of Anril 1899.
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham.