Improvements in Friction Ratchet Mechanism.
Year: 1894

page_text: Date of Application, 15th Jan., 1894-Accepted, 24th Feb., 1894
COMPLETE SPECIFICATION.
Improvements in Friction Ratchet Mechanism.
I, WILHELM LORENZ, of 57 Krieg Strasse, of Karlsruhe, in the Grand-
Duchy of Baden, Kingdom of Prussia, German Empire, 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 following
statement:
This invention relates to a mechanical movement, in which the rotations of a
crank or crank-disk are transferred on a wheel or dise by means of a lever fitted
loosely to the shaft or axle of said latter wheel or disk, and by a pawl loosely fitted
to the end of said lever, and acting on the periphery of the wheel, the lever being
connected with the crank or crank-disk by a rod causing said lever to oscillate
when the crank rotates, so that the wheel is intermittently moved by the intermittent
action of the pawl.
This intermittent or step-by-step motion may be turned into a continuous one by
the employment of two levers, two pawls and two connecting-rods, Figs. 1 & 3,
instead of but one of these parts, the pawls then being arranged on opposite sides
of the wheel or disk to be rotated. Independent from this the velocity of the
intermittent or of the continuous rotation may be altered, i.e. may be decreased or
increased by a link (Figs. 7-9) arranged between the connecting-rod proper of the
crank, and the one or two rods oscillating the lever-arms, the link thus transferring
the oscillating to- and fro-motion of said connecting-rod to the rods connected to said
one or two levers.
When employing two levers and, consequently, two pawls, I may let act the
latter on two wheels or disks arranged either on one axle or on different, but
parallel ones (Fig. 10), which may be in the same plane, as well as in different
ones.
As the velocity imparted to the wheel or disc from the crank or crank-disk is
not a uniform one, may provide means for rendering said velocity wholly or
nearly uniform; this may be attained, for instance, by connecting the crank-pin
with the connecting-rod, or the crank or crank disk with its axle or shaft not
rigidly but elastically (Figs. 12-14), as will be more fully described hereinafter.
In order to make my invention more clear, I refer to the accompanying drawing,
in which similar letters denote similar parts throughout the different views, and in
which:
Fig. 1 shows the disk to be rotated acted on by two pawls secured to two levers,
the latter being connected by rods with one and the same crank;
Fig. 2 shows a side-view of the disk, the upper pawl with its accessories being in
section;
Fig. 3 shows a modified configuration and arrangement of the pawls;
Fig. 4 shows a side-view of the above modification ;
Fig. 5 shows another modification,
Fig. 6 shows a third modification,
Fig. 7 shows the disk driven by but one pawl, and a link arranged between the
rod of the crank, and that of the lever;
Fig. 8 shows the combination of two levers and rods with a link,
Fig. 9 shows a modification in the means for adjusting the link;
Fig. 10 shows two levers and pawls acting on two disks;
Fig. 11 shows a modified mode of construction, in which a strap is used instead

page_text: Fig. 12 shows an elastic connection between crank-pin and connecting-rod ;
Fig. 13 shows an elastic connection between crank-disk and shaft, the disk being
in section, and
Fig. 14 shows a back-view of this latter elastic connection.
Referring to Figs. 1 & 2, a is the wheel or disk, which shall be driven from
the crank or crank-disk b. Axle c of wheel a forms the fulcrum for the two pairs
of levers d d', which are connected with crank b by the rods e e'. The bolts f, by
means of which the parts d and e, or d'and e' respectively, are connected, hold the
pawls gg by means of suitable links h; the pawls are shaped in this case like
brake-shoes, and the upper pawl is pressed on to the periphery of disk a by a
spring i.
If, now, crank 6 rotates in the direction of arrow 15, the pawls g and g¹ press
alternately onto the periphery of disk a, and slide back again; that is to say, one
pawl is pressing whilst the other is sliding, and, as the changes of these functions
of the two pawls occur always simultaneously, the wheel or disk a is set into a
continuous rotatory motion.
Instead of using a disk or wheel with a flat periphery, as in Figs. 1 and 2, I may
employ a pulley, the periphery of which is shaped like that of a rope-pulley, as
shown as an example in Figs. 3 & 4. The pawls are, consequently, shaped
accordingly, and they are held in that mode of construction not by the bolts f
connecting the levers d d' and rods e e', but by special bolts f".
I may entirely dispense with the bolts f, and may attach the rods directly to the
pawls, if the latter are formed into double-armed levers by an elongation or arm g³,
as represented in Fig. 5. Rude is connected with this arm g' by a bolt f, and the
leverd is, thus, moved indirectly from rod e by said elongation g³.
It may be desirable in some cases to change the direction of movement of disk
or wheel a. For this purpose I have devised the changeable double-pawl g³, Fig. 6,
which is formed by a three-armed lever, the middle-arm of which is connected by a
hinge with a rod displaceably arranged in a casing 1. The latter is journalled in
the upper end of lever d, and contains a spring m, which may be compressed by a
small disk or by a pin a fixed to rod k.
In the position shown in Fig. 6 in full lines, the left-hand foot of the double pawl
is the one which intermittently acts on disk a. If, now, the pawl is turned into the
position shown in dotted lines, the other foot of the pawl will be the working one,
and the wheel will be transported during that time, in which the pawl is drawn
backwards by rod e, so that, consequently, the direction of rotation is reversed.
As has been mentioned already in the preamble, the velocity of (movement in one
or the other direction) may be altered by effecting the transfer of the motion of
crank on wheel a by means of a link. I have shown one mode of construction of
such an arrangement in Fig. 7, in which o is the link, which is fulcrumed at p to a
suitable part of the frame. The link is oscillated from crank or crank-disc b by
the connecting-rod e³, and the oscillatory movement of the link is transferred to
Rode has an
rode by means of a slide 9 arranged in the slot or groove of link o.
elongation e² extending beyond slide g; said elongation is connected by a rod r with
an angular band-levers, by means of which slide g may be raised or lowered within
the slot or groove of link o, so that, consequently, the extent of movement of pawl g
may be increased or decreased.
The same arrangement, or a more or less similar one, may be connected also with
two levers and pawls, as shown as an example in Fig. 8, in which the two levers d d'
are operated by the mediation of link o. Only one, however, of the rods ee has
the elongation. The link is fulcrumed in this case by its lower end (at p'), the
connecting-rod being attached to the upper end of the link.
Instead of employing a straight link, as in Figs. 7 & 8, I may use also a curved
one, as shown at o' in Fig. 9. And further, instead of raising or lowering the
elongation g', or the connecting-rod respectively, by a band-lever (as s in Figs. 7
& 8), we may attach said rod r to a slide t, Fig. 9, adapted to be moved by a
threaded spindle u. This latter may be rotated by a handle v.
j

page_text: When using two levers and two pawls, it is not indispensably necessary to let
them act on one and the same wheel or disk, but two wheels or disks may be
employed, as represented for instance in Fig. 10. The arrangement of the parts is
in this case a somewhat other one; the alterations are, however, perfectly
immaterial, as the manner of working is not in the least changed. The two
wheels a a' are held by the two parallel axles c c', and the link (which, as a matter
of course, may be dispensed with, as the two rods e e' can be moved directly from
the crank see Figs. 1-6) is arranged between said two axles. The further details
are clear from the drawing without any further explanation.
I need not indispensably use a pawl for transferring the motion of lever d
(Figs. 5 & 6) to the wheel or disk, but I may employ instead thereof other means,
by which a larger surface of contact can he attained. Such a means has been
shown in Fig. 11, in which a strap wo is used, the two ends of which are secured to
two arms of a three-armed lover 9 journalled to the projecting upper end of
lever d. As soon as rod e is moved in the direction of arrow 16, the strap is first
pressed against the disk and the latter is then turned a certain way according to the
extent of movement of rod e. On the back-stroke of rod e, the disk is released from
the strap, and lever d is drawn backwards together with the loose strap, disk a
remaining in its newly gained position.
When driving the disk or wheel continuously in the manner represented in
Figs. 1, 3, 8 & 9, the rotation of the disk will not be a uniform one on account of
the irregular extent and velocity of motion of the connecting-rods e e¹ (Figs. 1 & 3),
or connecting-rod e* (Fig. 8) respectively in different parts of their or its path.
To overcome this, the two devices shown in Figs. 12-14 have been devised.
Concerning Fig. 12, rod e is attached to crank-pin b not directly but by means of
a slide b' adapted to glide to and fro in the slotted rear-part e' of rod e. Springs y y'
are arranged between the slide and the opposite inner surfaces of the slot, and the
force is then transmitted not directly but by the mediation of said springs. I have
shown this arrangement in Fig. 7 connected with the other parts of the mechanical
movement, and it will be seen, that slide b' is directly in the midst of the slotted
parte, when the resistance offered by rod e' is in its maximum. Rod e³ is, then,
moved by the crank not with the velocity of the latter, but with a slower velocity
as part of said resistance is taken up by the springs y and y. The resistance
offered by rod becomes the less the inore lever d approaches the end of its path,
and the velocity of rode becomes during this time a correspondingly greater one
than that of the crank, as the springs give off now their force to said rod es, so that,
consequently, the velocity of lever d with its pawl 9 is made wholly or nearly
independent of the velocity of the crank, and the disc, therefore, rotates with
a velocity wholly or nearly uniform.
The same result may be attained by making the connection between the crank-
disc (Figs 13 & 14) and its shaft z elastic. This is performed in said figures
by means of flat steel-straps y situated with their middle parts in a suitable hole in
the end of shaft 2, whilst the two ends of said elastic plates y³ catch between
suitable projections at the inner surface of the rim of the disk. The manner of
working of this mode of execution is essentially the same as that described with
reference to Fig. 12.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a mechanical movement, the combination with a lever having its fulcrum
on the shaft or axle of a wheel, disk or pulley, and carrying a pawl adapted to act
on said wheel, disk, or pulley, of a crank connected with said lever, and adapted to
oscillate the same, for the purpose as described.
2. In a mechanical movement, the combination with a lever having its fulcrum.
on the shaft or axle of a wheel, disk or pulley, and carrying a pawl adapted to act
on said wheel, disk or pulley, of a rotating crank connected by a rod with said lever,

page_text: said rod being adapted to turn the rotatory motion of the crank into an oscillatory
motion of the lever carrying the pawl, for the purpose as described.
3. In a mechanical movement, the combination with a lever having its fulcrum
on the shaft or axle of a wheel, disk or pulley, and carrying a pawl adapted
to act on said wheel, disk or pulley, of a link connected with said lever as
well as with a crank, the latter being adapted to oscillate said lever by the
mediation of said link, for the purpose as described.
4. In a mechanical movement, the combination with a lever having its fulcrum
on the shaft or axle of a wheel, disk or pulley, and carrying a pawl adapted to act
on said wheel, disk, or pulley, of a link connected with said lever by a slide, and of
a rotating crank connected with said link by a rod adapted to turn the rotatory
motion of said crank into an oscillatory motion of the link, the slide of the latter
being adapted to be displaced, for the purpose as described.
5. In a mechanical movement, the combination with two levers having their
fulcrums on the shaft or axle of a wheel, disk or pulley, and carrying each a pawl
adapted to act on said wheel, disk or pulley in a like direction, of a crank
connected with said levers, and adapted to oscillate the same, for the purpose as
described.
6. In a mechanical movement, the combination with two levers having their
fulcrums on the shaft or axle of a wheel, disk or pulley, and carrying each a pawl
adapted to act on said wheel, disk or pulley in a like direction, of a rotating crank
connected by rods with said levers, said rods being adapted to turn the rotatory
motion of the crank into an oscillatory motion of the levers carrying the pawls,
the latter being adapted to act alternately on the wheel, disk or pulley, for the
purpose as described.
7. In a mechanical movement, the combination with two levers having their
fulcrums on the shaft or axle of a wheel, disk or pulley, and carrying each a pawl
adapted to act on said wheel, disk or pulley in a like direction, of a link
connected with said levers as well as with a crank, the latter being adapted to
oscillate said levers by the mediation of said link, for the purpose as described.
8. In a mechanical movement, the combination with two levers having their
fulcrums on the shaft or axle of a wheel, disk or pulley, and carrying each a pawl
adapted to act on said wheel, disk or pulley in a like duection, of a link connected
with said levers by a slide, and of a rotating crank connected with said link by a
rod adapted to turn the rotatory motion of said crank into an oscillatory motion of
the link, the slide of the latter being adapted to be displaced, for the purpose as
described.
9. In a mechanical movement, the combination with two levers having their
fulcrums on the shaits or axles of two wheels, disks or pulleys, and carrying each a
pawl adapted to act each on one of said wheels, disks or pulleys, of a crank
connected with said levers, and adapted to oscillate the same, for the purpose as
described.
10. In a mechanical movement, the combination with two levers having their
fulcrums on the shafts or axles of two wheels, disks or pulleys, and carrying each a
pawl adapted to act each on one of said wheels, disks or pulleys, of a rotating
crank connected by rods with said levers, said rods being adapted to turn the
rotatory motion of the crank into an oscillatory motion of the levers carrying the
pawls, for the purpose as described.
11. In a mechanical movement, the combination with two levers having 'their
fulcrums on the shafts or axles of two wheels, disks or pulleys, and carrying each
a pawl adapted to act each on one of said wheels, disks or pulleys, of a link
connected with said levers as well as with a crank, the latter being adapted to
Oscillate said levers by the mediation of said link, for the purpose as described.
12. In a mechanical movement, the combination with two levers having their
fulcrums on the shafts or axles of two wheels, disks or pulleys, aud carrying each
a pawl adapted to act each on one of said wheels, disks or pulleys, of a link
connected with said levers by a slide, and of a rotating crank connected with said

page_text: link by a rod adapted to turn the rotatory motion of said crank into an oscillatory
motion of the link, the slide of the latter being adapted to be displaced, for the
purpose as described.
13. In a mechanical movement, the combination with a lever having its
fulcrum on the shaft or axle of a wheel disk or pulley, and carrying a double-pawl
adapted to act on said wheel, disk or pulley in either direction, of a crank
connected with said lever, and adapted to oscillate the same for the purpose as
described.
14. In a mechanical movement, the combination with a lever having its
fulcrum on the shaft or axle of a wheel, disk or pulley, and carrying a double-pawl
adapted to act on said wheel, disk or pulley in either direction, of a rotating-crank
connected with said lever by a rod adapted to turn the rotatory motion of said
crank into an oscillatory motion of said lever, the two working parts of the double-
pawl being rigidly connected with a lever connected moveably with a displaceable
rod, the latter being constantly acted on by a spring tending to press one or the
other working-part of the double-pawl onto the wheel, disk or pulley, for the
purpose as described.
15. In a mechanical movement, the combination with a lever having its
fulcrum on the shaft or axle of a wheel, disk or pulley, and carrying an angular
lever holding the two ends of a strap surrounding said wheel, disk or pulley, of a
crank connected with said lever and adapted to oscillate the same, for the purpose
as described.
16. In a mechanical movement, the combination with a lever having its
fulcrum on the shaft or axle of a wheel, disk or pulley, and carrying an angular
lever holding the two ends of a strap surrounding said wheel, disk or pulley, of a
crank connected with said angular lever, and adapted first to strain said strap, and,
then, to turn the said first lever together with the wheel, disk or pulley, for the
purpose as described.
17. In a mechanical movement, the combination with a lever having its
fulcrum on the shaft or axle of a wheel, disk or pulley, and carrying a pawl
adapted to act on said wheel, disk or pulley, of a crank connected elastically with
said lever, and adapted to oscillate the same, the force imparted to the crank-axle
being transmitted to said lever by the mediation of springs, for the purpose as
described.
18. In a mechanical movement, the combination with a lever having its
fulcrum on the shaft or axle of a wheel, disk or pulley, and carrying a pawl adapted
to act on said wheel, disk or pulley, of a crank connected elastically by a rod with
said lever, and adapted to turn the rotatory motion of said crank into an oscillatory
motion of said lever the force imparted to the crank-axle being transmitted to said
rod by means of springs inserted between the crank-pin and said rod, for the
purpose as described.
WILHELM LORENZ,
By F. G. Cassell,
Of Cassell & Co.,
22, Glasshouse Street, Regent Street, London, W.,
Agent for the Applicant.