Improvements in Driving Mechanism for Ratchet Wheels.
Year: 1899

page_text: Date of Application, 25th Nov., 1899-Accepted, 20th Jan., 1900
COMPLETE SPECIFICATION.
Improvements in Driving Mechanism for Ratchet Wheels.
I, PETER CHRISTIAN HENRIKSEN, of 95, Vesterbrogade, Copenhagen, Engineer;
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 follow-
ing statement;-
-
'
The object of the present invention is a driving mechanism for ratchet-wheels
by which the disagreeable noise always connected with the use of the ordinary
ratchet-wheels when the pawl drags upon the ratchet-teeth will be avoided,
while, moreover, the wear of the pawl as well as of the ratchet-teeth is reduced
to a minimum. In the present mechanism the pawl will, after each movement
of the ratchet-wheel, be automatically lifted out of gear with the ratchet-
teeth and remain in this position during the drawing backward of the working
lever, so that the pawl will not at all touch the teeth of the ratchet-wheel until
this is again turned.
-
The invention is illustrated on the accompanying drawing in which-
Figures 1 and 2 show a mechanism of the kind described, seen in side-elevation
and in two different positions.
Figure 3 is the same mechanism seen in front elevation; and
Figures 4 to 10 are various forms of construction of the said device.
a is the axle that has to be turned and upon which the ratchet-wheel b is
rigidly fixed. On one or on each side of the wheel loose discs c are arranged
upon the axle, in which discs the axle may turn but which by means of a clamp d
are fixed in a suitable manner to the frame. A ringe which is movable and
slides upon the outer rim of the disc with a certain friction, is placed around
each one of the discs c. The rings e are cut open and their extremities connected
by screws f by means of which the rings may be tightened more or less around.
the discs c. The friction between these and the rings e may thus be regulated.
The rings e have flaps placed directly opposite each other and connected by.
two bolts h and i. On the bolt a working lever is arranged in such a manner
that it may be moved to and fro. The bolt i carries the pawl which has the
shape of a double lever, whose one arm gears with the teeth of the ratchet-wheel b
and whose other arm stretches along the one side of the working lever k. This
latter arm is by means of two links m, arranged moveably as well on the pawl /
as on the working-lever k, connected with the working lever.
The mechanism acts in the following manner:
In the position of the pawl 7, shown in Figure 1, this one gears with the teeth
of the ratchet-wheel b, and the working lever is moved in the direction indi-*.
cated by the arrow n whereby the ratchet-wheel is turned. When the working
lever k is moved in the opposite direction (arrow o Figure 2) i.e., during the back
stroke. the working lever will, when the friction between the rings e and the
discs c be sufficiently great, commence to turn round the bolt h and one arm of
the pawl being connected with the working lever by means of the links m, the
pawl will turn round the bolt i so that the lower arm gets disengaged from the
teeth of the ratchet-wheel b. Everything is thus adjusted. that the upper arm

page_text: of the pawl will bear against the working-lever, k just in the moment when the
lower arm of the pawl is disengaged, (Figure 2), and a further turning of the
working lever in the direction of the arrow o will consequently cause a turning
of the working-lever, the pawl, and the rings e as a whole; the rings turning
upon the dises e. During this movement the pawl will remain- disengaged from
the ratchet wheel so that neither noise nor wear may ensue.
When the movement in the direction of the arrow is at an end, and the work-
ing lever is moved the opposite way, the working lever will again turn round the
bolt and thereby bring the pawl, the upper arm of which is moved forward by
the links m, into gear with the ratchet wheel. The working lever, the pawl,
and the rings e will thereupon altogether, as one single piece turn round and move
the pawl-wheel 6 and the axle a as long as the working lever is moved in the
direction of the arrow n.
To permit the mechanism to work as described above the friction between the
rings e and the fixed discs c must be greater than the friction arising from the
moving of the working lever and pawl in relation to the ring e. It is evident
that the friction, which in the form of construction here described is produced
between the rings e and the fixed disc c and which only serves to offer a certain
resistance against the turning of the flap g around the axis of the ratchet-wheel,
may also be produced in some other known manner, for instance by a spring or
brake.
By adjusting the travel of the working lever k, in such a manner that the total
movement of the pawl is only a trifle greater than a full number of teeth, even
the slight noise that is produced by the pawl striking against the teeth may be
avoided.
Figure 4 shows a modification of the device in which the small play between
the pawl and the working lever may be accurately adjusted by means of a set-
screw p and check-nut r.
Figure 5 shows another modification. Here it is not the pawl 7 but the
link m which by impact against the working lever k limits the movement of
the pawl 7.
From the above it will be seen that generally speaking the action of the
mechanism is dependent upon the movement of the sides of a jointed square in
relation to one another. These sides are the pawl 7, the working lever and the
sides and m lying between these, of which the side g is moveable (with a
suitable friction) round the axis of the ratchet wheel.
7. Maintaining the principal features the appearance of the mechanism may be
very much varied.
In Figure 6 for instance the sides and m of the above-mentioned square are
interchanged, that is to say that the side m takes the place of the working lever.
By moving the rod m in the direction of the arrow the pawl is brought to gear
with the ratchet-wheel, while movement of the rod in the opposite direction disen-
gages the pawl from the ratchet-wheel, until the movement.is stopped by means
of a suitable stopper. In a similar manner m may for instance act as pawl
and ór k as the working-lever.
Figure 7 represents a form of construction of the mechanism in which m forms
the working-lever as well as the pawl, while and are changed into links.
Figure 8 represents a form of construction in which the link m is omitted, and
the nawl directly connected with the working lever by means of a pin s upon the
pawl arranged to slide in a slot in the drawing rod. The slot may be either
curved or straight. The mechanism may in this case be looked upon as if the
side m of the aforesaid square were indefinitely long.
Another of the sides of the square may in similar manner be replaced by a
pin (with or without slide-block) moving in a slot.
Even two of the sides of the squares may simultaneously be indefinitely long,
... replaced by pins, with or without slide blocks, moving in slots. Figure 9
shows such a form of construction. The pawl and the working lever are in one

page_text: piece and are provided with slots in which pins w, fixed on the flap g, may
move. In this case the sides and are indefinitely long.
In Figure 10 there is lastly, shown an extremely simple form of construction
the sides of the square being here indefinitely small. Pawl and working lever
are in one piece and arranged to turn round a bolt a upon the flap g.
An adjust-
able stopper, a set-screw y with check-nut z limits the movement of the working
lever.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what I
claim is:-
1. A driving mechanism for wheels characterized by a jointed square whose
three sides are formed by the pawl e a working lever k, and a link m, while the
fourth side is formed by a part arranged to move with a suitable friction round
the axis of the ratchet-wheel, whereby the working lever by its to and fro' move-
ment displaces the sides of the square in relation to each other in such a manner
that the pawl is moved against the ratchet wheel when the working lever is
moved forward and away from the ratchet-wheel during the return stroke of the
working lever.
2. A form of construction of the driving mechanism for ratchet-wheels indicated
in Claim 1 characterized by a moveable ring e or the like arranged concentrically
with the axle of the ratchet-wheel and upon the pawl as well as the working
lever a, moveably mounted, for instance by means of bolts i and h, the said pawl
and working-lever being outside the ring e mutually connected by means of a
link m.
3. A form of construction of the mechanism indicated in Claim 2 characterized
by one or two moveable rings e mounted with a suitable friction upon one or
two discs c fixed to the frame of the apparatus, and in which the axle a of the
ratchet-wheel may freely turn round, the said rings e being mutually connected
by means of two bolts h and i upon which the working lever k and pawl i re-
spectively are moveably mounted and mutually connected by means of two
links m the length and point of fixing of these links being thus adjusted that the
pawl, when its one arm is out of gear with the teeth of the ratchet-wheel, bears
with its other arm against the working lever k, while the first mentioned arm
is brought to gear with the ratchet-wheel, when the latter arm is moving away
from the working lever by the turning of same.
4. In the mechanism described in Claims 2 and 3 the arrangement that the
ring or rings e are cut open and their free ends connected by screws f for the
purpose of regulating the friction between the disc e and the rings e.
5. Modifications of the form of construction of the mechanism described in
Claims 2 and 4 characterized thereby that the sides of the jointed square indicated
in Claim I change parts, as shown as examples in Figures 6 and 7, or thereby
that one or two of the sides of the square are replaced by pins with or without
slide-blocks moving in slots, as shown in Figures 8 and 9.
Dated this 25th day of November 1899
EDWARD EVANS & Co.,
27, Chancery Lane, London, W.C., Agents for the Applicant.