IMPROVEMENTS IN ELECTRIC LAMPS OR LIGHTING APPARATUS
Year: 1883

page_text: PROVISIONAL. SPECIFICATION left by Henry Harris Lake at the Office
of the Commissioners of Patents on the 5th March 1883. Communicated to
him from abroad by Edward Weston of Newark, New Jersey, United States
of America.
HENRY HARRIS LAKE, of the firm of Haseltine, Lake, & Co, Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN ELECTRIC LAMPS OR LIGHTING
APPARATUS" [a communication to him from abroad by Edward Weston of
Newark, New Jersey, United States of America.]
This invention relates more particularly to clutch or clamp lamps, that is to say
lamps in which gripping mechanism for the carbon-holder is employed in con-
junction with a suitable system of electro-magnets, and it consists mainly in
improvements in the character and disposition of the magnets and armatures
whereby a better and cheaper lamp than those heretofore made may be produced.
The following is a description of the nature of the said invention that is to say.
The lamp-regulating mechanism is enclosed in a suitable casing and is mounted
on an insulated plate. The said casing is clamped to a board containing terminal
hooks and surmounted by a tube that covers the hole through which projects the
carbon-holder. On the said plate is screwed a U-shaped standard or frame. From
the sides extend short arms and from its top extends another arm.
To the short arms a rectangular frame is pivoted, the said frame consisting of
soft iron side pieces, and ends of brass or other non-magnetic metal. On opposite
sides of the frame are secured electro-magnets, one for the main circuit and the
other the shunt magnet, the cores of the two being parallel, and both being so
placed that the sides of the pivoted frame will pass close in face of their poles.
A carbon-holder passes through guides in the U-shaped frame and insulated
plate, and a suitable clutch, such as a perforated plate and tail piece or any similar
device surrounds said carbon holder and is hinged in proper manner to a bar
carried by the sides of the pivoted frame, or is otherwise connected with a part of
the said frame capable of imparting to it the requisite movement. A plate is
secured to the end of the upper arm by a slot and screw and is bent over to form
a step for the end of the clutch.
A dash-pot, the piston rod of which is hinged to the upper part of the casing, is
connected with one end of the pivoted frame.

page_text: It will be readily perceived that the pivoted frame and its appurtenances may
be considerably modified without departure from the spirit of this invention.
For instance the ends may be dispensed with, or the sides may be fixed to a rock-
shaft, or other alterations of a like nature may be made without materially affecting
the result.
In conjunction with the aforesaid board I employ for suspending the lamp, a
second board on which are screwed plates provided with means for engaging the
suspending terminal hooks, and connected with binding posts.
On the under side of the second board is also arranged a cut-out or safety device
consisting of a magnet included in the main circuit of the lamp, a vibrating
armature, a contact stop or arm, and a wire connecting one terminal of the lamp
with the said armature and containing a resistance equal to the combined resistance
of the magnet coils of the lamp and the carbons.
The magnet which is in the shunt circuit around the lamp, may be wound in
either direction, but the best results will be obtained by magnetizing it so that its
poles correspond with those of the main circuit magnet. In either case the shunt
magnet acts in opposition to the other magnet, and draws back the frame into a
position to release the clutch when the arc lengthens.
The special advantages which the described arrangement of magnets and
armatures present, are that both ends of the cores are utilized, though both cores
form really a part of the same magnetic system, since one of the sides may be
regarded as the connecting piece, the other as the armature.
It may be stated that other forms of feed mechanism may be combined with the
swinging or pivoted frame, but in practice I prefer that described.