An Improved Automatically Disengaging Safety Coupling for Shafts.
Year: 1897

page_text: Date of Application, 24th Nov., 1897-Accepted, 19th Feb., 1898
COMPLETE SPECIFICATION.
An Improved Automatically Disengaging Safety Coupling for Shafts.
We, JESALAS MARGULIES and GUSTAV GIER, both of Lodz, in the Empire of Russia,
Engineer and Mechanician respectively, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement:-
This invention has for its object an automatically disengaging coupling adapted
in the event of a mishap to automatically disconnect the shaft, and in the event of
the slipping off of a belt to suitably regulate the speed of the transmission shaft
without stopping the steam engine or motor.
The invention is shown in the accompanying drawings, in which:
Figure 1 is a longitudinal section:
Figures 2 and 3 are cross sections on the lines, and y-y, respectively.
This invention is more particularly intended to bring the shaft to a standstill
in case a workman be caught by a belt and to regulate the transmission in case a
belt slips off. For the first object a wire is arranged to run in proximity to the
shaft, which wire is connected with the disconnecting mechanism and is thus
adapted to operate the same when a body at any part of the shaft encounters the
said wire.
The coupling between the driving shaft a and the transmission shaft b is effected
by a toothed disc c keyed on the shaft in the teeth of which disc there engage
clutches or pawls d. These pawls are revolubly mounted in a disc e which
is keyed in turn on the shaft b. So long as the clutches or pawls bear against the
teeth, the shaft 6 will be rotated together with the shaft a. The disconnecting is
effected by bringing these clutches or pawls out of engagement with the teeth.
For this object a second disc g is arranged in proximity to the disc e so as to
loosely revolve on the nave of the latter. in which disc g elongated holes h,
(Figure 3) are provided. In these holes the clutches or pawls engage by means
of a pin i. If the disc be rotated against the disc e (in Figure 3 to the right) the
pins i will move in the holes h away from the axis until the clutches are brought
out of engagement with the teeth of the disc e, thus producing a disconnecting.
This movement of the disc g relative to the disc is produced by the disc g being
embraced by a brake band k which is drawn taut or applied by means
of a weight 1. The brake band is not normally on, as the
weighted lever is held in an inclined or horizontal position by means of any
suitable stop device. This stop device is connected with the wire hereinbefore
mentioned which runs by the side of the transmission shaft, in such a way that in
case of a shock or blow being given to the wire, the stop device is released so that the
weighted lever drops and draws on the brake band. As by this means the disc
is braked, whilst the disc e continues to rotate further, the desired displacement
of both discs relative to one another is effected, and as before mentioned produces
the disengagement of the coupling.
When the device has performed its duty, it is then only a question of again
coupling up the two shafts. This is attained by the disc o instead of boine

page_text: "
mounted to travel entirely loosely on the nave of the disc e, being connected with a
set ring m by means of a spiral spring n, the set ring being in turn mounted on
the nave of the disc c. During the time in which the apparatus is uncoupled, the
spiral spring n is stretched and is held in this position by a wedge » connecting
the discy and the set ring m as it projects through the latter into an opening in the 5
former and is prevented springing out by means of a semicircular shaped spring p.
When it is desired to again couple the two shafts, the wedge o is, by means of
any suitable device, drawn out so far as to release the disc g. By the action of
the stretched spring n the disc will then be rotated against the set ring and thereby
against the disc e in a direction contrary to that in which the disconnecting took 1
place. The clutches or pawls will also be axially adjusted in the opposite direc-
tion so that they again come into engagement with the teeth of the dise c. Both
shafts are thus again coupled or connected.
of 2
One circumstance must however not be lost sight of. The shaft a revolves with
its ordinary speed, whilst the shaft is stationary. If therefore the coupling is 1
effected in the manner hereinbefore described it would naturally take place with
such a shock that a breakage of the device would be inevitable. In order to over-
come this, the shaft is already set in rotation before the actual coupling takes
place. For this object a brake disc is arranged to loosely revolve on the disc c
and is connected therewith by means of a spiral spring r, the brake band
said disc s being capable of being applied or drawn taut by means of a hand
lever. Wedge shaped brake segments 2! are arranged on the periphery
of the disc e, which correspond with suitable notches in the disc e. These
segments v rest on a steel band 10 which may be pressed apart by
means of arms, whilst the arms engage with the pins in elongated
holes in the disc s. If the discs be braked by pulling the lever it moves
itself relatively against the direction of the arrow P and the pins y and the arms a
move in the elongated holes of the said disc towards the shaft and press the
ring w apart by the displacement or movement of the elliptical pins. This ring
in turn presses the segments into the notches of the disc c and forces the latter
thereby to take part in the movement of the disc c. The shafts a and then
revolve at an equal speed and by the withdrawal of the wedge o in the manner
hereinbefore mentioned the connection or coupling of the pawls d may be effected
without the slightest shock.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
1. An automatically disengaging safety coupling for transmission shafts charac-
terized by a toothed disc (e) being mounted on the driving shaft () and adapted
to carry with it the transmission shaft (b) by engaging pawls (7) carried by a
disc (e) mounted on the said driven shaft (b) until the said pawls (d) are released
or disconnected by the braking of a dise (y) which is loosely and revolubly mounted
on the pawl dise (e) and carried round with it by a connection of springs, the said
brake disc (9) having tangentially directed slots (h) to adjust the pawls when it
is braked or released, the coupling being further characterized by:-
() The brake device (k) being operated or thrown into action by means of a
pull device, such as a wire, chain or the like arranged parallel to the shaft out
of reach of the discs, wheels and the like arranged on the driven shaft, the moment
the said wire, chain or the like is drawn out of its position by being encountered
by any body carried round unintentionally with the rotating shaft, and
(b) The automatic re-engagement of the pawls () in the toothed disc (c) after
the brake () has been released being prevented by means of a wedge which is
constantly carried round with the pawl disc (e) and which is adapted to spring
automatically into a recess (a) in the brake disc () after the mutual rotation of
the two discs (g & e) has produced a full or thorough disengagement of the
pawls (7), substantially as hereinbefore described.

page_text: 2. A shaft coupling such as described, characterized by a spring brake ring (vw)
being arranged on the toothed disc (c) and adapted to come into firm contact with
a suitably notched surface on the pawl disc (e) the moment a disc (s) having a
spring connection with the toothed disc (e) and carried round with it is braked to
cause a mutual rotation of both dises (s & c). whereby link pieces (r) which with
one end bear against the spring brake ring ( ) and with the other end against
the disc (s) are brought out of their radially directed position into a tangenial posi-
tion, substantially as described.
Dated this 23rd day of November 1897.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicants.