An Improved Electrical Current Reverser and Testing Key.
Year: 1895

page_text: Date of Application, 22nd Feb., 1895
Complete Specification Left, 22nd Nov., 15-Accepted, 15th Feb., 1896
PROVISIONAL SPECIFICATION.
An Improved Electrical Current Reverser and Testing Key.
RICHARD HARVEY TONKING 84 Annandale Road East Greenwich Kent
Electrician do nereby declare the nature of this invention to be as follows:-
...
1. An improved method of reversing the direction of an electrical current by
means of a sliding switch which locks automatically in the positions necessary for
ordinary use; which method enables many tests to be performed without the aid
of a second key or other apparatus usually required.
inch thick has on it
inch from the
"L" & "E"
2. An ebonite base 6 inches long by 4 inches wide &
six fixed ebonite pillars & one moveable ebonite pillar, "P : the fixed pillars are
marked "L," "E" "Z," "C," "K," and "K₁," & when describing their positions
on the base their centres are given as the points measured to. The six pillars
stand in two rows, "L," "Z," & "K," on the left side of base, 1
edge thereof, & "E," "C," & "K₁," in like manner on the right.
are each 1 inch from back edge of base, "Z" & "C" are midway from back to
front, & "K" & "K, are 1 inch from front edge of base. The moveable
pillar, "P," is midway between the two sides of base & 18 inches forward from a
line joining "L" & "E."
"
3. The moveable ebonite pillar, "P," 1 inch diameter at the bottom & tapering
to 1 inches at the top, divided from the top downwards into two segments for
more perfect insulation by a slot "S," inch wide & 2 inches deep, is secured
by the bottom end to a brass turntable with a projecting lever, "1," of spring
brass.
66 "
S
4. The turntable is secured to the ebonite base by a shouldered brass screw
in such a way as to admit of the turntable & pillar being freely revolved around
the screw,
s," but without any rocking on the base.
"
5. The end of the lever, "," which has an upward set, works in a ratchet, ","
which limits the motion of the turntable & locks the lever in the necessary
positions.
6. On the top of each segment of the divided pillar, "P," is fixed a strip of
spring brass, each insulated from the other by the ebonite of the pillar, & more so
by the deep slot, "S." These strips, "b" & "b₁," project equal lengths before &
behind this pillar, "P," & are parallel to one another & to the lever "."
7. The two ends behind the pillar, "P," on the opposite side to the lever, "1,"
are bent downwards & back towards, & return almost to, the divided pillar "P,"
where, having platinum contacts on their under surface, they rub on two platinum
"" & "
contacts connected respectively with terminals on "L' E," & always
so rub.
"
8. In front of the divided pillar, "P," 2 inches distant from its centre, are five
platinum contacts, all on the same level, placed on the line of the arc made by
the contact points on the ends of the brass strips "b" & "," which project
before the pillar, "P"; each of these five contacts is separated from the next by
inch air space.
9. The central contact, "c," inch by inch surface, is connected with a
terminal on "C," & with nothing else.
"
Q. 1f. evaatival of the

page_text: central contact, "c" each inch by inch surface, are connected respectively
with the terminals on "K" & "K₁," which are joined to the two ends of a short
circuit key.
11. The outside two contacts, "" & "z," to the right & left respectively
of "k" & ",," each inch square surface, are connected together & to the
terminal on
Z'"
12. When the lever, "," is over to the left as far as the ratchet "" permits,
"L" is placed in connection with "Z" & "E" in connection with "C," by
means of the brass strips, “¿” & “b₁" respectively, on the segments of the divided
pillar.
13. When the lever, "," is over to the right the reverse is the case, "L" being
then in connection with "C," & "E" in connection with "Z."
14. When the lever, "," is in the central position, where it firmly locks, "L"
can either be connected to "E" by means of the short circuit key, K," "K₁,"
or insulated by breaking the circuit at "K." The contacts in connection with
the pillars "Z" & "C" are then disconnected from each other & from any other
part of the key.
66
15. The advantages claimed are that the contacts are all rubbing ones & are not
themselves touched by the operator, the lever, "," doing all the necessary work
of putting on, taking off, & reversing the current, (one hand only being required)
without any possible chance of the electrical contacts being strained out of
position by over-pressure on the lever, "/"; that when the battery is not in use,
that is, when the lever, "," is in the central position, the two poles of the battery
are free, thus avoiding all chances of running down or short-circuiting the battery;
that all the working parts are easily seen & easily got at to be cleaned or
examined; & that the battery can be reversed with or without "L" being put
to "E" during the operation of reversing, a very great consideration with many
electricians.
The accompanying drawings of two sheets (with duplicate copies) are not final,
but only sent to aid in explaining the action of the key.
Dated this 19th day of February 1895.
An Improved Electrical Current Reverser and Testing Key.
I, RICHARD HARVEY TONKING of 84 Annandale Road, East Greenwich,
Kent, 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 relates to a new or improved instrument or apparatus for
reversing the direction of an electrical current or testing key or galvanometer
reverser or means for enabling various electrical tests to be made not only easily
and quickly but without the aid of a second key or other apparatus usually
required heretofore-my invention having many advantages in use notably the
contacts are all rubbing ones and are not themselves touched by the operator as
the necessary work of putting on taking off or reversing the current is done by
the movement of a single lever or arm (one hand of the operator only being
required) and furthermore by my present invention I avoid any chance of the
electrical contact being strained out of position by any undue pressure on the said
operating lever; also when the instrument is not in use the two poles of the
battery are left perfectly free thus avoiding any chance of running down or short
circuiting of the battery; all the parts of the instrument are easily seen and
readily got at to be cleaned or examined; another advantage obtained being that

page_text: by my invention the battery can be reversed either with or without the "line"
being put to "earth" during the operation of reversing the battery current which
is a desideratum with many electricians.
And in order that my invention may be easily understood and readily carried
into practice will proceed to fully describe same with reference to the drawings
hereunto annexed.
Fig. 1 is a plan, Fig. 2 a side elevation and Fig. 3 an end view (looking in the
direction of the arrow Fig. 2) of an instrument or apparatus according to my
present invention.
Similar letters of reference indicate corresponding parts throughout.
A is the base of ebonite or other suitable non-conducting material upon which
are mounted six fixed pillars or supports LE Z C K and K and also the slotted
revolvable pillar or support P of ebonite or other suitable non-conducting
material.
The size of the said base A and relative positions thereon and to one another
respectively of the said six pillars LEZCK and K¹ may advantageously be
as follows ;-
The base A may be 6 inches long by 4 inches wide and inch thick and has
on it the said six fixed pillars and one movable pillar P the fixed pillars are
marked L EZC K and K and when describing their positions on the base their
centres are given as the points measured to.
The six pillars stand in two rows L Z and K on the left side of the base 1 inch
from the edge thereof and E C and K' in like manner on the right. L and E are
each 1 inch from back edge of base, Z and C are midway from back to front and
K and K are 1 inch from front edge of base.
The movable pillar P is midway between the two sides of base and + inches
forward from a line joining L and E.
The movable pillar P may be 1 inch diameter at the bottom and tapering
to 1 inches at the top divided from the top downwards into two segments for
more perfect insulation by a slot P¹ inch wide and 2 inches deep.
Or such parts may be of other suitable measurements and otherwise mounted
relatively to one another in any suitable manner without departing from the true
nature of my present invention.
If desired the instrument or the base A thereof may be supported on four
(or other suitable number of) legs or feet A¹ of ebonite or other suitable non-
conducting material as shown in the drawings herewith and such feet or supports A¹
will be found very advantageous particularly in instruments for use at sea as same
can be made to fit in corresponding holes in a stand or table to receive same and
thereby keep the instrument in its place (i.e. prevent it sliding about) while using
same in a sea-way. I wish to remark however that I herein make no separate
claim whatsoever to such short legs or feet A'.
P is slot in the movable pillar P.
is the head of a headed pin stud or pivot which is free to turn in a recess
formed to receive same in the bottom end of said pillar P-a shoulder on which
head s' fits closely like a turn-table in the plate a¹ so that there is no rocking or
sway possible.
The shank s of this headed pin passes through a circular hole (which it fits
accurately as aforesaid) in the circular plate or other suitable end a' of the
operating lever a² the other or free end of this lever operating in a ratchet which
limits the motion of the turn-table and locks the lever in the necessary positions
and then this lever a² is advantageously turned upwards and terminates in a knob
or button a by which said lever is operated.
Said shank s of this pin or stud is advantageously square below said plate a¹
(or other suitable form) and passes right through a hole of corresponding shape in
the base A in which it fits closely so that it cannot revolve and same is held in
position on the base A by a milled nnt such as sx (or equivalent) for instance the
shank s may terminate in a recess in the base A and be secured in position by a

page_text: nut such as s² as shown in dotted lines in Fig. 2-so that the pillar P can be
adjustably secured on the base A and by reason of the headed pin's not revolving
therefore there is no tendency to loosen the nut (or s²) thereon.
I is a flat contact surface connected by the arm with the ordinary or any
suitable contact screws or means for joining up the line wire on the pillar L.
"
e is a similar flat contact surface connected by the arm e' with the ordinary or
any suitable contact screws or means for joining up the "earth or return wire on
the pillar E.
2 and 2 are two separate flat contact surfaces each connected (the latter through
the bent arm) by the arm 2 to the ordinary or any suitable contact screws or
means for joining up the one pole of the battery (for instance the zinc pole) on the
pillar Z.
c is a flat contact surface connected by the arm cl with the ordinary or any
suitable contact screws or means for joining up the other pole of the battery (for
instance the copper or carbon) on the pillar C.
to the pillar K.
to the pillar K¹.
k is a flat contact surface connected by the arm
is a flat contact surface connected by the arm
M is a spring arm or short circuit key fixed to the pillar K¹ by the milled nut N
on the screw N which latter is carried on the pillar K' and passes through the
bent under end M' of said arm M and thereby normally keeps the latter in contact
with the arm k³.
The other end M2 of this spring arm or key M normally rests above and just
clear of the contact surface on the top of the pillar K that is to say the end M² of
said key M will normally remain supported above out of any connection with the
arm. A sliding button O is mounted on the key M and adapted to slide thereon
lengthwise at one end thereof-one part Ox of this button O' being of such a size
and shape as to be adapted to pass under a cross bridge O' fixed to the pillar K so
that in forcing said part of the button O under said bridge (or equivalent) O
thereby the end M2 is forced down and locked and held in contact with the
arm (see Fig. 3) thus forming a short circuiting device or key as hereinafter
explained.
bare two strips of spring brass (or other suitable material) respectively fixed
-on opposite sides of the division or slot P₁-to the top of the two segments
(formed by such slot P¹) of the pillar P so as to be completely insulated from one
another.
These strips or contact pieces 661 are respectively turned under at the one
end 6x as shown (see Figs. 1 and 2) so that a spring contact surface 6x is thereby
formed on the arm which rubs on the aforesaid contact surface and always so
rubs and a similar contact surface 6* on the arm b' which rubs on the aforesaid
contact surface e and always so rubs-the surfaces laud e being made of such a
size that the ends will not pass off same within the limits of the movement
imparted thereto (through the pillar P) by the lever a².
The other end 6** of each such arm 6 and 61 respectively are advantageously
bent downwards (as shown in Figs. 1 and 2) and each terminating as a spring arm
over the said contacts k and k respectively which latter together with the
contact cand 2 are all in exactly the same plane so that the said ends b** will
rub over same and pass on and off them readily and yet make good electrical
contacts as hereinafter explained.
All the said five contact surfaces 2 ke k' z' as also the two others and e are or
may be of platinum or other suitable material.
A great advantage obtained by this invention is that by having these rubbing
contacts the latter will automatically remove any dust or dirt and keep a cleau
contact surface and thereby ensure perfect contacts always being made.
The operation is as follows:-
When the operating lever a is in mid-position as in Fig. 1-thereby connection
is made from the "line" wire L through the parts bk k² to K-while
connection is made from E through the parts e' e b¹ k¹ k³ to K-thus entirely out

page_text: of connection with the battery or either pole Z or C thereof and moreover the
circuit is broken at K and "L" is now insulated from "E"; or if desired by
pressing down the end M2 of the key M (as aforesaid) thereby connection is made
through from L to Ẹ viz. from L to K (and E to K') as aforesaid and thence
from K to K' through M M M'.
If now the knob a (Figs. 1 and 3) he moved to the left then the arm b¹ rubs on
contact c and current from the pole C passes through band e from C to E while
the arm
simultaneously comes into contact with surface z and current from Z
passes throughz band 1 from Z to L.
To reverse the current-the button a is moved over to the opposite extreme
whereupon the arm b now comes over and in contact with surface c whereby
current from C passes by way of c and from C to L while simultaneously the
arm is moved into contact with the surface z¹ and the current from Z now passes
through and e from Z to E.
On returning the lever a² to mid-position all connection with the battery is again
cut off.
When the instrument is to be used only as galvanometer reverser and short
circuit key combined then the end 6xx (of each of the rubbing contact strips b
and may advantageously be widened or the contact surfaces z ke k¹ z¹ may be
widened or otherwise arranged in suchwise that the end 6xx of the strip will not
leave the contact surface before the end 6×× of the strip 6 has touched the
contact surface z (and similarly in the opposite direction---so that does not leave k
before has passed onto z¹).
Otherwise it is of importance that such short circuiting of the battery is
absolutely prevented as first described.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. An electric current reverser and testing key having two contact strips both
carried on a pillar or support but insulated from one another said pillar or support
being so mounted on the base as to be capable of turning thereon in combination
and acting in conjunction with two separate contact surfaces connected to the
terminals of the line and earth (or return wire) on one of which surfaces one end of
one said strip rubs and on the other said surface one end of the other said strip
rubs and five separate contact surfaces arranged in the same plane over which the
other end of each said strip rubs and makes or breaks contacts or reverses the
battery current substantially in the manner and for the purposes hereinbefore
described.
2. An instrument or apparatus for the purposes described consisting of a base of
insulating material such as A supporting a pillar thereon such as L carrying
a contact such as I connected to one terminal of the line or cable a pillar such as E
carrying a contact surface such as e connected to the terminal of the earth or
return wire pillars such as K and K' carrying contact surfaces such as k and k¹
respectively and means to connect or disconnect K and K' a pillar such as C
carrying a contact surface such as c connected to one pole of the battery or side of
the galvanometer said contact c arranged in the same plane with and between the
two said contacts k and ¹ a pillar such as Z carrying two contact surfaces such
as z and 2 both connected to the other pole of the battery or other side of the
galvanometer said contacts and being arranged with the contacts kek¹
between same and all in the same plane in combination and acting in conjunction
with two separate contact strips such as insulated from one another and
mounted on a pillar such as P adapted to turn on the base A a lever such as a²
connected to said pillar P a knob such as a by which to operate said lever a rack
such as r to limit the movement of said lever a² and pillar P and consequently
limit the movement imparted to the ends 6 and 6** respectively of the strips b

page_text: and b which latter rub on the aforesaid contact surfaces le z kc k¹ and z'
substantially in the manner and for the purposes herein before set forth.
3. An instrument or apparatus arranged constructed combined and acting
substantially in the manner and for the purposes hereinbefore described and
illustrated in the drawings hereunto annexed.
Din oond das of November 1905
TONGUE & BIRKBECK,
Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.