A New or Improved Tap-switch for Electric Incandescence Lamps.
Year: 1899

page_text: A New or Improved Tap-switch for Electric Incandescence Lamps.
I, GEORGE GARDNER, of 7, Northampton Grove, Mildmay Park, Canonbury, 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 particu-
larly described and ascertained in and by the following statement: -
This invention relates to a new or improved tap-switch which is more especially
intended for use in connexion with a holder for electric incandescence lamps in
which a current of high voltage is employed, and the principal objects of the
invention are to ensure a greater and more positive break between the switch
and the terminal points when the tap is switched off than is usual in fittings
of this description, and to provide perfect insulation between the various parts.
In the accompanying drawings is illustrated a tap-switch constructed in accord-
ance with this invention in which Figure 1 is a front elevation; Figure 2 a
similar view but with the lower front portion removed and turned one half of
a revolution to the right so as to shew the two adjacent faces of this part of
the tap-switch; Figure 3 a side elevation looking towards the tap handle;
Figure 4 a plan view; Figure 5 a similar view but with the upper part removed;
Figure 6 a longitudinal section on line a, b, of Figures 1, 4 and 7; Figure 7
a back elevation; Figure 8 a detail view shewing the special means employed
for insulating the tap handle; and Figure 9 a front elevation of the holder which
contains the parts illustrated, and to which the incandescence lamp is connected
in the usual manner.
Similar letters of reference relate to like parts in all the figures of the
drawings.
c, d is a block of porcelain, vulcanite, or other suitable non-conducting
material, preferably made in two pieces, as seen clearly in Figure 2. Each of
these semi-blocks is fitted with a spring contact ef by which electrical con-
nexion is established between the tap-switch and the lamp in the usual manner.
It will be seen that these spring contacts e and f are completely insulated the
one from the other, the contact e being in electrical connexion with one con-
ducting wire g which enters the hole h and is clamped therein by the screw 2,
and the contactf being in electrical connexion with the switch terminal which
is screwed into the metal tube in which the spring contact f works. The other
switch terminal k is screwed into a metal block 7 sunk into the insulating block c
as shewn in Figure 2, and is in electrical connexion with the other conducting
wire m which enters the hole and is clamped therein by the screw o.
?) is a
block of insulating material preferably attached to the block d by the tee-shaped
brass plate as shewn in Figure 7. "This box or casing p carries between its
two side walls the copper switch-bars rands formed from one piece of metal
as shewn, and mounted on the axis or spindle t which turns in bearings in the
said side walls as shewn. The switch bars r and s are caused to turn to a limited
extent with the axis by means of the pin which is screwed through the said
axis and bears against the back portion of the switch bars rands which latter are

page_text: "
shaped as seen in Figure 6 so as to cause them to press against the blade spring Z
which spring retains the said switch bars in either the " on or off" position
by bearing against one or other of their square sides as shewn. One end of the
axis or spindle t is formed with a flange (see Figure 8), to which is attached,
by screws or otherwise, the disc w of insulating material. The stem of the
handle y is furnished with a square or other head or flange z which is bedded
in the insulating disc w before the latter is attached to the flange of the axis t.
The handle or head y is attached to the stem x by the pin 2 or in any other
convenient manner. This means of connexion between the tap handle y and the
axis or spindle t is very secure, and the electrical current is effectually prevented
from passing into the handle y.
The blocks c and d may be held in position by the heads of the screws i and o
taking into corresponding recesses in the blocks c and d respectively, and when
placed in the holder (Figure 9) they are held securely in place without further
fastening. In some cases the blocks c and d may be in one piece, and the
metal pieces in which the wire-holes h and n appear are situated on the top of
the block and fixed thereto by screws or otherwise.
It will be understood that the current passes through the conducting wire g,
screw, spring contact e, through the lamp, spring contact f, terminal j, switch
bar n, switch bar r, terminal k, block 7, screw o, and conducting wire m.
It will also be understood that when the switch bars r and 's are turned by
the handle y out of contact with the switch terminals j and k, they are caused
to turn right back into the position shewn in Figure 6 so as to be quite free
from such terminals and make a long break thus avoiding any possibility of
sparking.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
First. A tap-switch for electric incandescence lamps which consists of the
blocks cd and box or casing p of insulating material, the switch bars r, s,
spring, terminals j, k, and spring contacts e, f, the whole combined, arranged,
and operating substantially as described with reference to the drawings, and for
the purposes specified.
Second. A tap-switch for electric incandescence lamps which consists of a
block c, d in one piece and box or casing p of insulating material, the switch
bars r, s, spring 1, terminals j, k and spring contacts e, f the whole combined
arranged, and operating substantially as described and for the purposes specified.
Third. In a tap-switch for electric incandescence lamps the means for in-
sulating the tap handle y from its axis or spindle ₺ substantially as described
with reference to Figure 8 of the drawings.
Fourth. The improved tap-switch for electric incandescence lamps constructed
and arranged substantially as described.
Total
T 1
1000