Year: 1888

page_text: We, SIDNEY SHARP and JULIAN MONEY VERNON MONEY-KENT both of Connaught
Mansions, Westminster in the county of Middlesex, Electrical Engineers, and HENRY
JOHN PAYNE of 1 River View Barnes in the county of Surrey, Engineer, do heroby
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 certain improvements in electrical switches of that class in
which a bar or bridge for making and breaking contact is not wholly operated by the
handle but in part by an auxiliary force independently of the control of the operator,
their object being in some degree to prevent liability of formation of arcs and
sparking.
"
In such switches as usually constracted the contact bar is acted upon by the said
auxiliary force in one direction only, viz., to spring the switch "off," the whole motion
of turning it on" being performed by the handle and sometimes the contact bar has
to be held "
on" by frictional spring catches, the spring for springing it "off" thus
being in compression or tension during the whole time that the switch is in use. In
other types the contact bar has been so connected with the handlo as to be necessarily
moved synchronously with it, either entirely or to a certain point, when the spring
"off" takes place, whereby imperfect contact is possible.
The object of our invention is to so arrange the switch as to sprung both "off" and
on" positively and instantaneously and independently of the control of the operator
from the moment at which the contact bar is moved. To this end we arrange the
contact bar quite free and independent of the handle, and so as not to be affected
until a certain degree of turning has been effected when by the simultaneous combined
action upon a rotatory block of peculiar form of a special arrangement of fixed and
independent spring contact is instantaneously and positively made or broken, and thus
imperfect contacts arcing and sparking are absolutely impossible; and further
according to our arrangement the springs are inactive except only during actual use
of the switch.
We will now more fully describe our improvements referring in so doing to the
accompanying drawings in which figures 1, 2 and 3 are plans of a switch with cover

page_text: "
and handle removed. Figures 1 and 2 show the switch on " and "off" respectively.
Figure 3 shows the parts in position just before action. Figure 4 is an alternative
arrangement of springs. Figure 5 is a cross section on centre line ay of figure 1.
Figures 6 and 7 are inverted plans of two arrangements of handle. Figures 89, 10, 11
illustrate different forms of block. Figures 12, 13 and 14 are alternative forms of
contact bars. Similar letters refer to similar parts in all of these figures.
A is the usual base plate of slate or suitable material and carrying the contact
plates aa which may have spring jaws to receive a contact bar having its ends plain,
or formed as illustrated in figures 12 and 13, or an ordinary brush bar may be used
with plain contact plates; no gripping action of the contact plates is required, a good
frictional contact only being essential. In a recess of convenient size and depth about
the centre of plate A are fixed four pins B B which can conveniently be cast upon
one plate p as shown.
Centrally in the recess is pivotted either upon a hollow spindle on the plate p or
otherwise the block C: This block may be of a square, diamond, rhomboidal, or oval
shape as illustrated in figures 8 to 11, and carries one or two pins cc on its upper
surface or the said surface may advantageously machined in two directions so as to
leave one or two projections ce as in figure 8; about the four sides or opposite quarters
of the block are disposed the ends of two or more sets of independent springs bb fixed
and disposed around the pins B B, and arranged either as in figures 1 or 4. Overlying
the block is a free contact bar E which may if desired be suitably formed about its
central parts to receive the thrust of the block pin or pins c as illustrated by figs. 1
and 2.
The operating or starting handle D may be fixed to the spindle d which passes
loosely through the contact bar E, the hollow spindle of the block C, and base plate A,
and is secured by a washer and nut with tension plate if desired at the base as at d¹
figuro 5 (but in case of using a brush contact piece the tension plate is necessary): or
the spindle may be in one with the block C and the handle fixed loose upon it as may
be most convenient: the lower surface of the handle D is provided with a plate d²
either straight as in figure 7 or provided with a slot das in figure 6, adapted to
take against the pin or pins c of block C; the usual casing covering the working parts
is provided.
The action is as follows:-
Assuming electrical contact to be made as in figure 1 when it is desired to break
circuit the first turning of the handle in the direction of the arrow brings one end of
slot 3 or one side of plate d² figures 6 and 7 against the pin or projection c of block C,
and further turning starts the rotary block C from its position of rest compressing
springs bb After a quarter revolution the block arrives at the dead centre position
shown in figure 3, the springs bb being now in full compression ready for action :
So far during this turning the contact bar is not affected, but on further turning the
instant the block C passes the dead centre the simultaneous combined action of all the
springs d d upon it in the same direction cause it to spring instantaneously "off" to
position illustrated in figure 2, by the thrust of the pin c against the bar E. Precisely
the same action takes place when the handle is turned in the reverse direction, and
remakes the contact. Thus it will be seen that no pushing action is applied by the
handle to the contact bar which is always free from the handle and the block, and
the action being so rapid and positive it is impossible by giving a central position to,
or holding the handle, or otherwise tampering with the apparatus to give a slow
motion to the contact bar, or to obtain imperfect contact, or to make ares and sparking:
A slotted plate similar to d³ figure 6 may be fixed to the base of plate p or in suitable
position to prevent the handle being turned continuously in the same direction or
further than is desirable.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. In an electrical switch the hereinbefore described means of both making and

page_text: breaking electric contacts instantaneously and positively consisting in the use of a
rotary block adapted to be turned through a given distance in either direction by the
operating handle and then to be instantaneously sprung over by a special arrangement
of springs to a position the reverse of its first position carrying with it a contact bar
independently of further action of the handle, and the control of the operator for the
purposes set forth.
2. In an electrical switch the use in combination of a rotary block carrying a pin
or pins, fixed independent springs, a free contact bar, and a starting handle all
constructed arranged and operating substantially as and for the purposes set forth.
3. The specific arrangements of working parts constituting the hereinbefore described
improvements in electrical switches for the purposes set forth.
J. C. CHAPMAN,
70, Chancery Lane, W.C.,
Agent for Applicants.