An Arrangement for Raising and Lowering the Seats of Operation Chairs.
Year: 1887

page_text: [Communicated from abroad by CLAUDIUS ASH and Sons of Jäger Strasse, No. 68,
Berlin, Manufacturers of Mineral Tooth and Dental Appliances.]
า
An Arrangement for Raising and Lowering the Seats of Operation
Chairs.
7
I ERNEST ASH of No. 30 Moorgate Street in the City of London Solicitor 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 followings
statement:-
The object of the combination of levers and wheels shown in the drawings
Figures 1-5, is not only to raise the seat of an Operation Chair in an easy and safe
way by means of the foot, but also to lower the seat in the same way without it being
necessary to make use of the hands.
The principal sketch Fig. I represents the longitudinal section in a vertical position.
The pedal lever t which is used to lower the seat is shown. See also Fig. 2. About
the centre of this lever tor t, (the latter serves to raise the seat q-Fig. 5) a revolving
hinge joint w is fixed by means of a screw. The connecting rod oo, hangs on the
hinge w, and is moveably connected with it. The upper fork of each rod o o, takes up
the catches PP, between it and the revolving plate levers n n₁, that guide them round
the axle of the cog-wheels. A spring fitted on each lever nn, and catch p p.
presses the lower ends of the latter against the circumference of the cog wheels,
these wheels zz, are obliquely cogged. It will be easily seen (Fig. 3) that a lowering
of the lever t, will be followed by a movement from right to left of the wheels z z₁ and
of the conical wheel ₁. The two plate lovers n n₁ are between the discs of the cog
wheels 2
The pedal levers have each two guiding levers h h, hung on their front ends,
through this the upwards and downwards movement of the parts is almost in a
straight line. Through this construction the catches p and p, which are between the
connecting rods oo, and the levers n n, work exactly on the surface of the cogwheel
discs, so that catching or irregular working together of the cogged cone with the
wheels, is rendered impossible.
:
From the sketch Fig. 2 a partly horizontal section through the axle of the cog
wheels, the connection can be seen between the cog arrangement and pedal levers,
which are at both sides of the wheel r, and are guided in the grooves kk; the up and

page_text: downwards movement of the rods tt, when they have been started by the foot is
controlled by the grooves kk.
xx, is the cross bar projecting up and downwards on the front ends of the levers t t₁
each of which is fitted with a fork to hold the guiding levers h₁. The pedal lever is
raised after each downwards movement by the self acting levers h h, and two powerful
springs which are fixed on to the frame.
The feet a are held together at the back by a cross bar the open space both
between the front and back legs a is in both cases filled up by an iron trellis to hide
the mechanism. This trellis having no connection with the mechanism is not repre-
sented in the drawings.
The feet a are connected below in the front by the bar f. Besides these two con-
nections the feet a are held together above by a strong diagonal connection, the side
flaps of which c, are tightly screwed to the upper part of the front feet a. The centre
of this connection consists of two conductors c and d which hold the axles of the
wheels zz, and in position. In the hollow centre post of the feet a is a piston with
up & downwards movement which has two pivots on the sides of the upper cross
bar, on which the scat 7 Fig. 5 is fixed, so as to revolve. In the centre of the cross
connection of the piston & (Fig. 1) above the conductor c, a cylinder with flat thread
is fixed, to guard against it turning on its axis.
It is now easy to see from the drawings that on the raising of the cylinders, the
piston b will ascend with the seat g, or the reverse. The raising or lowering of the
cylinders is effected by the turning of the conical cogwheel which has a thread
fitting that of the cylinder s.
The conductors c and d have smooth edges, and suite in size the outer diameter of
the cylinder.
The small wheel which serves as nut, is set in motion by the above mentioned
largo wheel 111 and as already explained on pressing down the pedal levert the seat I
is raised. In the samo way the lowering of the seat takes place on pressing the
pedal t, (Fig. 3 and 4).
In order to make it possible to raise and lower the seat without trouble, it is
naturally necessary, to bring the catches pp, away from the cog wheels &
This is simply effected through the upper ends of the catches, when the pedal is at
the highest point, pushing against the rib i (Fig. 1 & 3) and thus freeing them-
selves. As soon as the pedal or t, is pressed down, the springs, bring the
catches pp at once into contact with the teeth of the cog wheels z and
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
1. An arrangement for raising and lowering the seats of Surgical or Dental
Operation Chairs through use of two pedal levers which are conducted by guiding
levers in such a manner that the lines of motion are almost in a straight line substan-
tially as described.
2. The arrangement of the connecting rods in connection with the above mentioned
pedals which rods are connected by the revolving hinge with the levers in the upper
fork end of the catches and which take up the guiding plate lever and thus cause
through pressing down the pedal levers with the foot a partial turning of the wheels
which gives motion to the conical wheel substantially as described.
3. The arrangement of a fixed cylinder on the piston which can be raised or
lowered as desired through a conical wheel substantially as described.
Dated this 29th day of December 1887.