Improvements in Adjustable Pendants for Lamps or the like.
Year: 1899

page_text: Date of Application, 4th Mar., 1899-Accepted, 10th June, 1899
COMPLETE SPECIFICATION.
Improvements in Adjustable Pendants for Lamps or the like.
I, DAVID SCHLESINGER, of 34, Oranienstrasse, Berlin, in the Empire of Germany,
Lamp Manufacturer, 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 an improved locking device for lamp rods and the
like, enabling the lamp or other suspended object to be maintained at any desired
height without the employment of chains or counter weights.
The operation of this improved locking device. is based upon the known prin-
ciple, which consists in arranging spherical bodies between the suspended object
and. conical surfaces, in such a manner that, owing to the weight of the part
enclosing the spheres itself, these spheres are forced into the gradually decreasing
space between the conical surface and the suspended object, thereby locking the
suspended extensible part in position.
With this known form of locking device, however, the suspended part can be
drawn down so as to occupy a lower position only by releasing the locking
arrangement whilst this is being effected. This is effected by screwing up a bear-
ing part, which forces the spherical bodies out of the locking position.
The object of this invention is to obviate the necessity for any such special opera-
tion, in order. that the suspended object may be lowered.
All that is necessary
for this purpose, is a slight rotation of the suspended part in a right-hand direc-
tion. Upon releasing the device, the weight of a tube becomes operative; this
tube, in conjunction with the suspended extensible part, effects a corresponding
left-hand rotation, so that the locking again takes place and the suspended exten-
sible part is automatically maintained in position.
In the accompanying drawing;
Figure 1 is a longitudinal section through an extensible lamp rod and
Figures 2 and 3 illustrate upon a larger scale, section through the locking
device in its two extreme positions.
Upon the lower extremity of an outer tube a which is suspended from the ceil-
ing, is screwed a conical box or casing b, which forms a portion of the locking
device and at the same time serves as a stuffing box for the extensible tube d.
The tube is inserted in a tube e and is guided in. its displacement in this latter
by means of a projection which enters a slot e' in the said tube e. Upon the
lower extremity of this tube e is provided a socket f, somewhat smaller in diameter
'than the outer tube a. The lower extremity of the socket is conical in shape
whilst upon its outer circumference is formed a spiral groove f¹ into which enters
a pin or stud b provided upon the box 6. In the conical end of the socket f are
formed three or more apertures f2 which serve to enclose steel balls g these latter
run between the outer wall of the tube d and the inner wall of the box b and
are displaced with the socket f, according as the tube d is raised or lowered.
In Figure 2 the balls 9 are shewn in the reduced portion of the conical box b,
which position they assume owing to the weight of the tube e itself. In this

page_text: position the suspended part (in this instance the tube ) is fixed in place. If it
is desired to fix the tube d at a different height, it is rotated slightly towards the
right-hand. As the projection d' only enables the tube to move independently
in a longitudinal direction, as it enters the slot e¹, in the tube e, this latter is
caused to participate in the rotation in a right-hand direction of the tube d. It
follows from this that the socket f, which is fixed upon the tube c, mounts upon
the pin of the box by means of its spiral groove f¹, its motion being spirally
upwards; the position assumed being shewn in Figure 3. The balls g.then occupy
a position in which there is a larger space between the tube d and the conical
part b, by reason of the displacement of the socket f, so that the tube d is no
longer locked and may therefore be raised or lowered, being guided in the slot e¹
of the tube e.
As soon as the tube d is released, the weight of the tube e is free to act, and
such action may be reinforced if desired by means of a spring (Figure 1)
causing the balls to resume the locking position (Figure 2) as the tube d, together
with the socket f effects a left hand rotation corresponding to the previous right
hand rotation.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
A locking device for extensible lamp rods or other suspended 'objects' charac-
terised by a socket (f) containing balls (g), which socket slides upon a pin or
stud (6) fixed to a conical box (6) by means of a spiral groove (f¹) formed in its
circumference, and participates in the rotation of the supporting tube or rod'();
in such a manner that it rises upon the rotation of this latter in a right-hand
direction, raising the balls into a wider portion of the box (b) and thereby releas-
ing the device, whilst, when the tube (d) is released the socket again descends and
locking is effected.
Dated this 4th dow of Vorel 1900
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.