Improvements in Electrical Switches.
Year: 1890

page_text: Date of Application, 17th Nov., 1890
Complete Specification Left, 17th Sept., 1891-Accepted, 17th Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in Electrical Switches.
I HENRY JAMES PIERCE of South Acton Works Beaumont Road South Acton
in the County of Middlesex Electrical Engineer do hereby declare the nature of
this invention to be as follows:―
This invention relates to electrical switches and more especially those for large
currents and the object of the invention is to cause the surfaces of such switches to
be held securely and closely in contact.
On a suitable insulating base are fixed face to face at an interval the two
vertical blocks between which contact is to be made; to another block or bearing
is horizontally pivoted a split or forked lever, and on the same axis is a handle
which may be moved down upon the lever aforesaid and thereafter by continuation
of its movement press the latter down between the contact blocks; within the fork
of the lever is pivoted a second lever, the one end of which extends outward and
terminates in a welge between the outer ends of the two blades of the forked con-
tact lever, and the other end of which projects backward within the fork to be
operated by a rising projection on the handle. When the lever is arrived with its
faces between the contact blocks an anvil set between these blocks stops the wedge
so that during further downward movement of the forked lever the wedge presses
the faces of the latter into firm contact with the blocks.
When releasing the lever, the handle having a certain amount of free movement
raises the inner lever pressing down the wedge, or in other words lifts the forked
lever by such downward pressure on the wedge reacting on the fulcrum thereof and
so releases the contact surfaces from the pressure of said wedge as they are lifted
from between the blocks after which a spring tends to lift them and hold them
raised.
'Dated this 17th day of November 1890.
HERBERT & Co.,
Agents to Applicant.
COMPLETE SPECIFICATION.
Improvements in Electrical Switches.
I, HENRY JAMES PIERCE, of South Acton Works, Beaumont Road, South
Acton in the County of Middlesex, Electrical Engineer, 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 stateinent :—
This invention relates to electrical switches and more especially those for large
currents and the object of the invention is to cause the surfaces of such switches to
be held securely and closely in contact.
In the drawing
Fig. 1 is a side elevation, Fig. 2 a plan of the improved switch.
On a suitable insulating base K are fixed face to face at an interval the two
vertical blocks J J₁ between which contact is to be made; to another block or
bearing is horizontally pivoted a split or forked lever A and on the same axis
(pin E) is a handle G which may be moved down upon the lever A aforesaid and
thereafter by continuation of its movement press the latter down between the con-
tact blocks; within the fork of the lever is pivoted a second lever the one end of
which extends outward and terminates in a wedge B between the outer ends of the
n •

page_text: two blades of the forked contact lever A and the other end of which projects back-
ward within the fork to be operated by a rising projection F on the handle G.
When the lever A is arrived with its faces between the contact blocks JJ an
anvil K set between these blocks stops the wedge B so that during further down-
ward movement of the forked lever A the wedge B presses the faces of the latter
into firm contact with the blocks J .J.
When releasing the switch by hand, the handle G having a certain amount of
free movement is drawn back and presses with its projection F against the under-
side of the rear end of the lever O and thus rocks this lever on its fulcrum C
pressing down the wedge B upon the anvil K¹. Since the wedge B is already
resting on this anvil, the aforesaid action lifts the forked lever A by such downward
pressure on the wedge reacting on the fulcrum C of the lever O and also causes
the contact surfaces to be released from the spreading pressure of said wedge Bas
the lever A is lifted froin between the blocks J J. The spring D promotes a
quick break by its interposition between the nose F and the lever O; the nose
presses against the spring and brings it into tension until its tension overcomes the
friction of contact and the lever A springs suddenly out of contact. E is a stop
for the lever O. M M'M' M* M* are fixing screws. LL contact screws.
The spring F here shown is a flat spring fixed in a notch in the wedge head of
the lever and extending underneath the lever O up to the rear end of this lever,
it rests midway against the bulged part of the lever O near the pivot C and con-
sequently its free end stands away from the end of the lever O so that the nose F
of the handle G, when the said handle is moved, comes first into contact with and
deflects the springs Fas hereinbefore stated. This construction of spring F¹ is
not essential, any spring which receives the pressure of the nose and com-
municates this pressure, by or under the tension of the spring, to the lever O will
answer the purpose. If "quick break" is not desired the spring may be wholly
omitted.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :—
The combination with the blocks J J¹ of the anvil K', the forked lever A, the
lover pivoted therein, the wedge B on said lever O and the handle G having the
nuse F the whole substantially as and for the purpose set forth.
HERBERT & Co.,
18, Buckingham Street, Strand, London, W.C., Agents to Applicant.