Improvements in the Construction of Electric Light Switches and Cut-outs.
Year: 1893

page_text: Date of Application, 6th Mar., 1893-Accepted, 29th Apr., 1893
COMPLETE SPECIFICATION.
Improvements in the Construction of Electric Light Switches
and Cut-outs.
We, CHARLES MARK DORMAN of Ordsal Electrical Works, Salford, in the
County of Lancaster, Electrical Engineer, and REGINALD ARTHUR SMITH of
Ordsal Electrical Works, Salford, in the County of Lancaster, 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
statement:-
Our invention consists principally of an improved form of the terminal pillar
described in our Patent No. 16434 Sept. 14th 1892. In our new terminal instead
of using the thick washer described in above Specification we form the terminal
with a shoulder or projection which rests direct on the metallic part of the switch
which is to be held down on the porcelain base, and if necessary drill and tap the
hole for pinching screw after the angular position of the terminal has been ascer-
tained by screwing it firmly down in the base with the metallic part in position
between the collar or projection on the terminal and the base.
Our invention also consists in a modification of our improved terminal pillar for
carrying electrical fuses. The object of our invention is to make it possible to
manufacture switches and fuses in which the metallic parts are attached to the
face of a porcelain base by means of screws tapped into the porcelain with the
smallest possible number of screws and these of comparatively large diameter and
coarse pitch.
Referring to the drawings
Fig. 1 is a section on the line ... of a single break switch fitted with our
improved terminals.
Fig. 2 is a plan of switch with cover and handle removed.
a. a 1. are the improved terminals screwed direct into the porcelain base b. one of
them a 1. holding down the contact tongue c. and the other a. the contact plate d.
In the switch shewn there are three tapped holes only in the porcelain base, two
to receive the terminals a. a 1. and one to receive the centre pillar of switch e.
which in addition to the terminal a. secures the plate d. to the base. When
necessary we use additional screws, steady pins, or other fasteners to attach the
fittings to the base.
It is obvious that our improved terminals are equally adapted for use for switches
of the double break type, in which case two of the improved terminals clamp the
two contact plates or jaws to the porcelain base with or without the use of additional
screws, steady pins, or fasteners, and the centre pillar of switch for carrying
the revolving arm may be screwed into the base as shewn in single break switch.
It is also apparent that our improved terminals are applicable for holding down
the contact jaws of switches of the tumbler type and also for switches containing
a fuse in same case.
Fig. 3. is a section and Fig. 4. a plan of our improved fuse pillar. It will be
seen that the hollow terminal is screwed direct into the porcelain base and the
fuse clamped on the upper part of the pillar between a shoulder on the pillar
and the nut g.
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. In electrical switches mounted on porcelain bases the method of securing the

page_text: by means of hollow terminal pillars into which the conductors are led and secured
by means of pinching screws, the terminal pillars being screwed direct into the
porcelain base and the holes for pinching screws drilled and tapped if necessary
after the angular position of terminal has been ascertained by screwing the pillars
hard down in the porcelain base with the metallic parts in position between the
collar or projection on the terminal and the base substantially as described and
shown.
2. In single break switches of the rotary type shown in drawings the method of
securing the metallic parts to base by means of the improved terminals and the
centre pillar of switch all screwed into the base, with or without the addition of
other screws, steady pins, or fasteners.
3. In double break switches of the rotary type the method of securing the con-
tact jaws, tongues or plates by means of the improved terminals with or without
the addition of other screws, steady pins, or fasteners, the centre pillar on which the
contact arm revolves being screwed direct into the porcelain base.
4. In electrical fuses the method of securing the conductors and fuse to the
porcelain base by means of hollow terminal pillars into which the conductors are
led and secured by means of pinching screws, the hollow terminals being screwed
direct into the porcelain base and the holes for pinching screws drilled and tapped
if necessary after their angular position has been determined by screwing the pillars
hard down, the fuse being held by means of a nut screwed on the upper part of the
pillar substantially as described and shown.
Dated this 3rd day of March 1893
CHARLES MARK DORMAN.
REGINALD ARTHUR SMITH.