IMPROVE- MENTS IN SWITCHES FOR ELECTRIC LAMPS
Year: 1882

page_text: LETTERS PATENT to Thomas William Cowan, Foreman to Messieurs Guest and
Chrimes of Rotherham in the County of York for an Invention of “IMPROVE-
MENTS IN SWITCHES FOR ELECTRIC LAMPS "
PROVISIONAL SPECIFICATION left by the said Thomas Willian Cowan at
the Office of the Commissioners of Patents on the 16th October 1882.
THOMAS WILLIAM COWAN, Foreman to Messieurs Guest and Chrimes of
Rotherham in the County of York "IMPROVEMENTS IN SWITCHES FOR ELECTRIC
LAMPS"
My Invention relates to Improvements in Switches for Electric Lamps whereby
a Lamp or a number of lamps can be lighted or extinguished at will after the
manner in which gas lamps are lighted and extinguished.
The switch constructed according to my Invention is provided with contact
pieces at each end suitably arranged for making contacts with the Lamp Bracket
or supports and with the Lamp Holder there being an insulating material between
these contact pieces.
In order to transmit or break the Electrical Current as required one of the
external conducting wires is passed through the switch-the other conductor is
formed by the Tubular Bracket or Lamp support.
To effect and maintain a good Electrical contact I cause a lever-acted upon by a
thumb-bit or other suitable arrangement carried on the insulating material (but in
metallic contact with one of the contact pieces aforesaid) to come into contact with
a spring on the other conducting portion of the switch which spring is placed in
compression or in tension making a firm and efficient contact when the lever is
turned in one direction to complete the circuit and light the lamp. On turning
the said lever in the other direction the contact is broken and the lamp
extinguished.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas William Cowan in the Great Seal Patent Office on the
16th April 1883.
THOMAS WILLIAM COWAN Foreman to Messieurs Guest and Chrimes of Rotherham
in the County of York "IMPROVEMENTS IN SWITCHES FOR ELECTRIC LAMPS"
My Invention relates to Improvements in Switches for Electric lamps whereby a
lamp or a number of lamps can be lighted or extinguished at will after the manner
in which gas lamps are lighted and extinguished. The switch constructed
according to my invention is provided with contact pieces at each end suitably
arranged for making contacts with the lamp bracket or supports and with the Lamp
Holder there being an insulating material between these contact pieces.
In order to transmit or break the electrical current as required one of the
external conducting wires is passed through the switch-the other conductor is
formed by the tubular bracket or lamp support.
To effect and maintain a good electrical contact I cause a lever acted upon by a
thumb-bit or other suitable arrangement carried on the insulating material (but in
metallic contact with one of the contact pieces aforesaid) to come into contact with
a spring on the other conducting portion of the switch which spring is placed in
compression or in tension, inaking a firm and efficient contact when the lever is.
turned in one direction to complete the circuit and light the lamp-On turning
the said lever in the other direction the contact is broken and the lamp
extinguished.
And in order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed Sheet of Drawings the same letters of reference
indicating corresponding parts in all the corresponding figures..
Figures 1 and 2 are elevations at right angles to each other and figure 3 is a
vertical section of a switch inado according to my Invention. The said switch
consists of the body part A which is made of insulating or non-conducting material
to which are secured the two contact pieces, one at B and the other at C, the
contact piece B consists of a socket piece or screwed connection by which the
attachment to the bracket or electrolier is affected.-This socket piece lins a metallic
conducting piece b, carried out to the exterior and there terminating in a plate b².
and spindle 6. upon which spindle a lever & is mounted so as to be capable of
turning thereon the said lever being provided with a thumb bit or button e-The
other contact piece C consists of a similar socket piece or screwed connection pro-
vided with a spring c. 9 is the one conductor passing through, the switch, the other
conductor being formed in part by the metal of the switch and fittings-When the
lever d'is turned into the position shewn in full lines in the drawing the metallic
continuity past the insulating material, A, is effected and the circuit is completed
and the lamps lighted but when the said lever is turned into the position shewn
by dotted lines in figure 3 metallic continuity through the switch is broken and
the lamps thereby extinguished. The plate b has stops thereon upon one or other
of which the pin d. on the lever d bears to limit the motion of the said lever in
either direction. Figures 4 and 5 represent in elevation and vertical section a
alightly modified construction of this switch wherein the continuity of metal
between the two contact pieces B and C, is effected by means of a handle thumb-
piece or button e, the stem of which is furnished with a pin e², which engages with
n helical groovef; formed on the part 0, the said stem of the handle or thumb-piece o,
terminating in a contact maker d. which is situated in a recess, a, made in the body

page_text: part A, of non-conducting material.-The spring c, is placed in compression between
the piece, C, and the said contact maker, d,-Thus, when the handle e, is turned in
one direction, the pin, e²., travels inwards in the groove f, and thereby the contact
maker, d, comes into contact with the strip, 62. projecting from the contact piece, B,
and the circuit is completed from the contact piece, B, through the strip, 62, contact
maker, d, and spring, c, to the part C, and so the lamps are lighted-On turning
the handle in the other direction, the said pin, e²., travelling back in the slot f,
causes the contact of the part d, with the part b². to be broken and the lamps'
are thereby extinguished.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the herein before in part
recited Letters Patent is :
The combinations and arrangements of parts constituting the Switches for
Electric lamps herein before described and illustrated in figures 1, 2 and 3 and 4
and 5, of the accompanying Drawings.
In witness whereof I the said Thomas William Cowan have to this my
Specification set my hand and seal this thirteenth day of April One
thousand eight hundred and eighty-three.
THOMAS. WILLIAM. COWAN. (L.S.)