IMPROVEMENTS IN ATTACHING LAMPS TO CARRIAGES AND SHIPS
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by John Haden at the Office of the
Commissioners of Patents on the 30th December 1878.
JOHN HADEN, of Birmingham, in the County of Warwick, Carriage Lamp Manu-
facturer, and JOHN WATHEN, of Birmingham aforesaid, Tool Maker and Machinist.
"IMPROVEMENTS IN ATTACHING LAMPS TO CARRIAGES AND SHIPS."
Our Invention consists in constructing in the manner herein after described the
part of the arm or "iron" fixed to the carriage or ship, and the part of the lamp
with which the arm or "iron" engages in attaching the lamp to the carriage or
ship.
The end of the arm which engages with the side of the lamp is flat and oblong.
We will herein after call the flat oblong part the end of the arm. In the outer
face of the end of the arm, that is, the face which when the lamp is fixed on the
arm is turned from the lamp, we form two cross grooves or depressions extending
all across the said end of the arm. The upper groove passes obliquely across the
end of the arm, and the lower one crosses the arm at a right angle. The lower
groove is curved at its lower side, and its upper edge is rounded at one end of the
groove.
At the side of the lamp a cap or case is affixed. This case is open at bottom for
the introduction of the end of the arm which fits in a recess formed in the case. In
the case described is a worm wheel turning upon an axis fixed to the case. This
worm wheel when the end of the arm is inserted in the case lies parallel with and
close to the outer face of the arm. On the face of the worm wheel in contact with
the arm are two projections or side cams, the one cylindrical and of a size proper
to fit in the upper groove in the end of the arm, the other a nearly straight rib
of a length nearly equal to the breadth of the ond of the arm. These projections
or cams make with the centre of the wheel an angle of about 120 degrees.
When the worm wheel is in such a position that the nearly straight rib or cam is
at its highest point, the end of the arm can be inserted in the case on the side of
the lamp, the said case can consequently be dropped upon the end of the arm
until the top of the arm comes in contact with the said rib or cam on the worm
wheel.

page_text: By now turning the worm wheel by means of a thumb plate on the end of the
worm engaging in it, the cylindrical projection or cam enters the upper groove in
the end of the arm, and by its motion the case is drawn down upon the end of the
arm. After the worm wheel has performed a nearly semi-rotation, the nearly
straight rim or cam enters the lower groove in the end of the arm, and by the
further motion of the worm wheel that portion of the arm between the two grooves
is tightly gripped between the two projections or cams on the worm wheel, and the
arm and lamp are firmly bound together.
By turning the worm wheel so as to reverse the motions of the projections or
cams on its side, the case of the lamp is first raised upon the end of the arm and
then liberated.
The motion of the worm wheel may be produced by a vertical or horizontal
worm. Or a wheel without a worm may be employed, the motion of the wheel
being produced by turning its axis. We prefer however the use of a worm and
worm wheel.
Our Invention is applicable to the attaching of lamps to all kinds of carriages
and ships.