Improvements relating to Electrical Lamp Holders.
Year: 1891

page_text: Date of Application, 4th Dec., 1891
Complete Specification Left, 2nd Sept., 1892-Accepted, 8th Oct., 1892
PROVISIONAL SPECIFICATION.
Improvements relating to Electrical Lamp Holders.
CHARLES SCOTT SNELL of Culver Park, Saltash Cornwall, Electrical Engineer
and WOODHOUSE & RAWSON UNITED LIMITED of 88 Queen Victoria Street
London, Electrical Engineers and Contractors, do hereby declare the nature of this
invention to be as follows:-
This invention relates to that class of lamp holder which is intended to take an
incandescent or glow lamp & refers more particularly to suspension holders.
The improvement consists in forming the terminals in such a manner that a
cylindrical tube acting as a nut on the face of the insulating disc (and containing a
spring and plunger in the usual manner for capped lamps or a spring hook for
uncapped lamps) is caused when rotated to pull upon a taper headed terminal screw
& by drawing it through a similarly tapered hole in the insulating disc to cause it
to receive a squeezing action so that a flexible lead or other conductor (inserted in
a deep saw or other cut longitudinally made in the terminal screw) will be tightly
grasped & good contact & a firm fastening thereby insured.
The taper hole in the base in conjunction with a suitably formed head to the
terminal screw may be used to grip or otherwise fasten the lead or conductor by
squeezing or wedging the same between the terminal screw & the surrounding
insulating material instead of acting upon the conductor as described above.
If the insulating material be of a comparatively weak nature to which it is unwise
to apply the bursting force due to pulling a taper headed screw through a similarly
formed hole, a plain parallel sided countersunk hole may be used & a washer dropped
within through which the taper or similar or equivalent head is pulled.
The taper headed screw may have flats formed thereon or a slight key or
excrescence arranged to prevent rotation or the screw head and the corresponding
socket for the same may be somewhat modified from the above without departing
from the general arrangement of a gripping or fastening attachment worked adjusted
or similarly acted upon by the rotation of a nut forming tube, or its equivalent
upon the opposite side of an insulating disc.
Dhan 1001
C. SCOTT SNELL.
WOODHOUSE & RAWSON UNITED, LIMITED.
W. T. Stutchbury,
Convatam
COMPLETE SPECIFICATION.
Improvements relating to Electrical Lamp Holders.
CHARLES SCOTT SNELL of Culver Park, Saltash, Cornwall, Electrical
Engineer and WOODHOUSE AND RAWSON UNITED LIMITED of 88 Queen
Victoria Street London, Electrical Engineers and Contractors, 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 :--
This invention relates to that class of lamp holder, which is intended to take an
clectric incandescent or glow lamp, and refers more particularly to suspension
holders.
The improvement consists in forming the terminal in such a manner, that a
cylindrical tube, acting as a nut on the face of an insulating disc (and containing a

page_text: spring and plunger in the usual manner, for capped lamps or a spring hook for
uncapped lamps) is caused when rotated to pull upon a taper headed terminal screw,
and by drawing it through a similarly tapered hole, in the insulating disc, to cause
it to receive a squeezing action so that the lead (inserted in a deep saw or other
cut, longitudinally made in the terminal screw) will be tightly grasped, and a good
contact and firm fastening being thereby insured.
The taper hole in the base in conjunction with a suitably formed head to the
terminal screw, may be used to grip or otherwise fasten the lead or conductor by
squeezing or wedging the same between the terminal screw and the surrounding
insulating material, instead of acting upon the conductor as described above.
If the insulating material is of a comparatively weak nature, to which it is unwise
to apply the bursting force, due to pulling a taper headed screw through a similarly
formed hole, a plain parallel sided countersunk hole may be used and a washer
dropped within through which the taper or similar or equivalent head is pulled.
The taper headed screw may have flats formed thereon, or a slight key excresceuce,
arranged to prevent rotation, or the screw head and corresponding socket for the
same may be somewhat modified from the above, without departing from the general
arrangement of a gripping or fastening arrangement worked, adjusted or similarly
acted upon by the rotation of a nut forming tube or its equivalent upon the other
side of an insulating disc.
The better to make our meaning clear, reference is made to the accompanying
drawings, in which similar letters refer to similar parts.
Fig. I. is a vertical section of a lamp holder, constructed according to this
invention.
Fig. II. is a plan of an insulating base.
Figs. III. and IV. are respectively plan and elevation of the terminal screw.
Figs. V. and VI. are respectively section and plan of the nut forming tube, in
the section the spring is shown in position.
Figs. VII. and VIII. show elevation and plan respectively of the plunger.
Figs. IX. and X. are plan and section respectively of a metal plate or
arrangement to prevent bursting stress on the insulation.
Figs. XI. to XX. are modifications in the shape of the terminal screw.
By reference to Fig. I. it will be noticed that the metal case A with shade holding
ring B, locknut C, socket D, cord grip E and cap F constitute a common form of
suspension holder. In regard to the insulating disc G (shown partially in section) we'
use a tapered hole, as shown, and a shoulder is provided for the nut H to work
against. Obviously the rotation of the tube H will draw the taper headed terminal
screw I downwards, as it cannot itself revolve having flats formed thereon,
corresponding to the shape of the hole see J Fig. II. and the plan Fig. III. This
movement causes a squeezing action or shutting up of the slotted terminal screw,
and the lead having been inserted in the slot a tight grip results making good
contact and a firm fastening.
A rib L may be used separating the two terminals and by a pin across the
tube H or a slight indentation as shown dotted at M in Fig. I. the spring, see Fig. V.,
may be retained in place even when the tube is detached entirely from the holder.
This spring is for clearness omitted from Fig. I.
Figs. III., IV., V., VI., VII, VIII. are too simple to require special
explanation.
In Figs. IX. and X. it will be observed that the washer takes the bursting action
resulting from the tightening up of the nut.
In Fig. XI. is shown a circular recess, in addition to a plain slot in the terminal
screw.
Figs. XIII. and XIV. show the slot in the sides of the screw.
Figs. XV. and XVI. show a plain hole in the head, bored at an angle.
Figs. XVII. and XVIII. show two key forming excrescences notched to take
the lead, this form of course working in a correspondingly shaped recess in the
insulating disc.

page_text: Figs. XIX. and XX. illustrate a plain transverse hole. In all the cases
illustrated from Figs. XIII: to XX. it will be seen that the lead becomes squeezed
between the metal work and the surrounding material when the terminal screw
is pulled down, there being no flexibility in the metal itself, as in the form described
with reference to Fig. I.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is :-
I. The construction and combination of the parts of a lamp holder, whereby
the rotation of a tube or equivalent nut forming appliance on one face of an
insulator, is caused to draw down a taper headed terminal screw on the reverse side,
in such a manner that it is caused to squeeze or grip the lead inserted in a slot
therein, substantially as and for the purpose herein described and illustrated in
Figs. I to VIII.
II. The combination in a lamp holder of a tapered and slotted terminal screw,
a perforated metal disc and a nut forming tube, substantially as and for the purpose
herein described and illustrated in reference to Figs. IX. and X. in the
accompanying drawings.
III. The combination in a lamp holder of a nut forming tube acting upon
terminal screws, in such a manner that the drawing down action is caused to squeeze
or hold the lead between the said nut and the surrounding insulating material,
substantially as and for the purpose described and illustrated in Figs. XIII. to XX.
in the accompanying drawings.
Dated his Decond day of September 1892.
C. SCOTT SNELL.
WOODHOUSE & RAWSON UNITED, LIMITED.
H. F. Easton,
Secretary pro tem.