Improvements in Pawl and Rachet Feed Mechanism.
Year: 1899

page_text: Date of Application, 16th Nov., 1899-Accepted, 16th Dec., 1899
COMPLETE SPECIFICATION.
Improvements in Pawl and Rachet Feed Mechanism.
We, Dr. LUIGI CEREBOTANI, Professor, of No. 5, Rothmund Strasse, and CARL
MORADELLI, Purveyor to the Court, of No. 2, Baum Strasse, both in the City of
Munich, in the Kingdom of Bavaria, and German Empire, 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 state-
ment:-
Hitherto there has been only one means known of attaining the advance tooth
by tooth of a motion, viz., the employment of an escapement wheel, this neces-
sitating, of course, the cooperation of a train with special motive power.
The attempts which have been made to attain an automatic forward motion
by means of another device, for instance by means of a hook with suitablo
brake, or of an anchor, click, arrangement of double wheels and the like, have
proved wholly unsatisfactory, since at the point where the impulse is rela-
tively energetic, or where the impulses follow one another in rapid succession,
it is always the case that the number of teeth advanced larger than the
number of impulses.
By means of the present invention this drawback is overcome and a tooth
by tooth advance effected with the same certainty as with an escapement, no
train being required.
The invention is illustrated by the accompanying drawing which shows one
manner in which it may be carried into effect. The four figures show the same
device in four successive positions, as will be described.
a is a ratchet wheel, in the teeth of which a spring pawl d, pivoted to an
arm engages, being held against the wheel by a spring . The wheel a is
provided with a series of pins p at right angles to its face and equal in number
to the number of teeth. The arm turns about the point o, between two
stops and e, being drawn towards the latter stop by a spring s.
It is repre-
sented as being impelled in the contrary direction by a force acting at the
point c, which force may be of any nature.
In addition to the pawl d, which may be of any convenient form, a kind of
double armed brake lever is pivoted to the arm at the point z, and moves
between stops m, n.
This brake lever is drawn upwards by a spring u attached
to the arm t. Upon the pawl d operating the wheel a, the left hand arm w of
the brake lever engages between two pins pp, in such manner that when the
wheel has advanced through the space of one tooth, the upper of the two pins
strikes upon the upper surface of the arm w and depresses it, so that the other
arm rises from-n and strikes against m.
Fig. 1 shows the device in position of rest. The point of the pawl d lies
between two of the teeth of the wheel a, whilst the point of the brake lever
lies slightly outside the circle formed by the row of pins p, and also a little
above the level of one of the pins.
Fig. 2 shows the device at the commencement of the action of the force at
tending to overcome the spring s. The pawl d, as shown, has not yet reached

page_text: the next tooth, whilst the point of the arm w has entered between the two pins
referred to and lies just clear of the one pin, so that if the pawl were to impart
an impulse to the wheel a sufficient to rotate it further than through the space
corresponding to one oscillation of the arm, the arm of the brake lever r
would come into operation to prevent this, as shown in Fig. 3.
This latter figure shows the device in the position it assumes after a com-
plete impulse. The pawl d has now reached the other tooth and has advanced
ine wheel through the space of one tooth. The one pin has, in the manner
above mentioned, not only reached the arm w lying under it, but has turned it
on its pivot z, so that its second or outer arm lies against the stop m.
This stop
effectually prevents further rotation of the wheel a, even though the impulse
given by the pawl d may be exceedingly energetic.
Fig. 4 shows the device in the position it takes up when the spiral spring s
exercises its force. The pawl d now lies in inclined. position. and is ready,
under the pressure of the spring to engage in the next tooth. The chief
member of the device, that is to say, the brake lever r is seen in the position
just prior to the moment when it becomes free from the pressure of the pin p
above it, and when it turns, in consequence of the action of the spring, so as
to be ready to spring in between the next pair of pins (as shown in Fig. 1.)
The essential feature of the invention consists in the pivotal arm r, the point w
of which, when it has left the interval between any two pins, can take up a
position in which it is ready to be inserted into the next space between two
pins, and so on. Were this movement not to take place, in the regularly pro-
gressive manner as illustrated by the drawing, there would be no control or
braking of the motion at all.
The system described may find a very wide application. It can, for instance,
be successfully employed for electric clocks, for tachometers and measuring
and indicating instruments generally, where a train of wheels or the like cannot
be used.
It. is obvious that the precise construction of the device may be greatly
varied; without departing from the essential characteristic of the invention.
Thus, for example, instead of pins 2, another form of projection or other forma-
tion of the wheel may be used to perform the same service. By a different
arrangement of the stops and spring u, the brake r, shown on the drawing as
a double armed lever, may also be given another form. The same applies to
the other members of the device.
Having now particularly described and ascertained the nature of our said in-
vention, and in what manner the same is to be performed, we declare that what
we claim is :-
A device for controlling the motion of automatic propulsion mechanism,
comprising a pivoted member having limited motion, influenced by the impel-
ling force against spring pressure, a spring pawl pivoted to said member, a
ratchet wheel receiving impulses from said pawl and provided with projections
arranged in circular form corresponding in number to the number of the teeth.
and a spring arm having limited motion pivoted to said pivoted member
adapted to engage between said projections and so brake the said ratchet wheel
at a required moment, all substantially as described.
Dated this 16th day of November 1899.
BOULT, WADE & KILBURN,
Agents for the Applicant.