Improvements in Mechanism for Producing Rotatory Motion from Reciprocatory Motion.
Year: 1894

page_text: Date of Application, 18th June, 1894-Accepted, 28th July, 1894
COMPLETE SPECIFICATION.
Improvements in Mechanism for Producing Rotatory Motion from
Reciprocatory Motion.
1, HERMANN GANSWINDT, of 76 Herbert Strasse, Schoneberg, near Berlin in
the Empire of Germany, 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 apparatus for producing rotatory motion in shafts and
such like by means of straps, cords, chains, or other similar device operated by
treadles, the to and fro movement of the piston of an engine, or any other suitable.
reciprocating device. The drawing or pulling device acts on round or curved discs
or pulleys, or on curved lever-like parts on the shaft that is to be driven. In the
first case the pulling device is fixed at one end to the pulley or disc and is carried
round the same in a direction suitable for giving the required motion to the shaft ;
in the latter case, that is when a curved lever-like part, or a part furnished with a
surface bounded by a curve, is employed on the shaft, the pulling device lies on
the curved surface so that the distance from the centre of the shaft of the point at
which the pulling device runs off tangentially from the lever-like part is the
effective lever arm for driving the shaft. In this apparatus the driving power
varies according to the varying length of the lever; on the other hand this
apparatus offers a means of employing an expansively-acting motor, the resulting.
variable force of which can be converted into a constant or uniform turning effect
on the shaft by varying the length of the lever arms to a corresponding degree by
properly curving the lever-like parts.
In the annexed drawings is shown, by way of example, a driving apparatus for a
shaft actuated by means of foot treadles, whereby a lathe or other tool for example
can be driven direct.
Figure 1 is a side view of the driving apparatus.
Figure 2 a front view of a ratchet pulley intended to turn loosely on the shaft.
Figure 3 a section taken on line -y of Figure 2.
Figure 4 a front view of the pawl carrier fixed on the shaft.
Figure 5 shows, in partial section, a modified arrangement with the ratchet pulley
fixed on the shaft and the pawl carrier loose thereon.
Figure 6 is a section through the shaft with side view of the ratchet wheel and
pawl carrier.
In the arrangement shown in Figures 1 to 4 the rotation of the shaft C is effected
by means of the draw-cords a a' which are connected to the foot treadles T T¹
which turn on a pint for example in a suitable bearing, so that they can be moved
up and down.
These draw-cords lead to cord pulleys A A' which turn loosely on the shaft C,
and have on their sides crown ratchet teeth s. These teeth come opposite to
pawls & contained in the carriers or holders B3 B₁ fixed on the shaft C. These
The
pawls are pressed by springs into gear with the crown ratchet teeth s.
number of crown ratchet teeth &, and of pawls k, is so arranged that a very slight
turning motion of the cord pulley A or A' with its crown ratchet teeth causes the
gearing of a ratchet tooth with a pawl. This turning of the cord pulley A or A' by
pressing down the treadle T or T' causes the shaft C to be carried round therewith
through the gearing of the ratchet teeth with one or more of the pawls. The
cords a al are so connected with their respective pulleys that the downward motion.
of each foot treadle effects a continuous rotation of the shaft in one direction.
The raising of the treadles and the backward rotation of the cord pulleys A and A'
for the purpose of winding up the cords a and a' in readiness for the next stroke of

page_text: the treadles is effected in any suitable way, for example, in the arrangement shown
it is effected by springs g g which may be connected by cords with the cord
pulleys A A or, as shown, with cord rollers formed therewith or connected
thereto.
In the arrangement shown in Figures 5 and 6 the ratchet teeth are formed on a
wheels fixed on the shaft C, and the spring-urged pawls K are so placed on the
cord pulleys A and A' that they gear with the ratchet teeth of the wheel s.
The driving apparatus above described operated by foot treadles possesses the
very practical and important advantage that the weight of the body can be utilised
in the most convenient manner for effecting the rotation of the shaft, by pressing
down each treadle alternately with the feat. Such a driving apparatus is more
regular in its action than the ordinary one used in lathes for example consisting of
a crank shaft operated by a single trendle that permits of the use of one leg only
which easily fatigues the operator and makes a regular continuous rotation of the
shaft impossible. Besides this the treadles being fulcrumed at one end, the
effective length of the lever arms, that is to say the position of the point of
application of the power can be varied, as also the size of the cord pulleys, whereby
the power acting on the shaft. can be altered as may be required without difficulty.
When instead of the foot treadles a motive power engine is employed with a
reciprocating piston driven by an expansive fluid and therefore with variable
pressure, instead of round cord pulleys, eccentric or curved lever-like parts may be
placed on the shaft and have the pulling devices connected thereto in such manner
that the greater pressure is caused to net ou a shorter lever arm and conversely the
smaller pressure on a longer lever arm with the consequence that the motion of the
shaft remains constant.
In the drawing an arrangement is shown in Figures 7 to 10 in which by means
of several curved discs or pulleys which I call cord snails the above mentioned
object is attained namely the utilization of a varying pressure such as that derived
from the piston rod of an explosive engine for the production of uniform rotatory
motion of a shaft for example.
In the drawing Figure 7'is a front view of the apparatus in its starting position
which as the apparatus revolves through an angle of 360° or 720° for one stroke of
the motor piston is also the terminal position for which latter position the pulling
cord is shown in dotted lines.
Figure 8 shows the same apparatus in the position corresponding to the middle
position (half stroke) of the piston of the motor.
Figure 9 is a side view of the cord snail on the shaft to which motion is to be
communicated (seen from the right hand).
Figure 10 is a plan of the cord snail on the countershaft.
The shaft C carries the cord or sunil pulley which runs loosely thereon and is
furnished with side teeth which gear with a corresponding half coupling (not
shown in the drawings) fixed on the shaft C like the pulley A or A' in Figure 1.
On the spiral path running round the snail pulley is placed the strap or pulling
cord which after being wound round the said spiral path outwardly from the
smaller radius to the largest radius that is to the outer end furthest removed from the
centre of the shaft is fixed there at a. A spring, the arrangement of which is
shown in Figures 7 and 9, effects the necessary backward return of the smail
pulley e after each pull of the strap or cord .
=
Instead of the strap or cord acting direct on the shaft C it acts in this case
through two cord snails pq fixed at a suitable angle to one another on a counter-
shaft r. The strap or cord is fixed at the outer end of the circumferential path
of the larger snail'p so that it winds up from the outer and larger radius to the
inner and smaller radius when the snails are turned in the direction of the arrow
and unwind from the inner and smaller radius to the outer and larger radius when
the snails are turning in the reverse direction. On the other hand the pulling strap
or cord a which is connected at one end with the motor piston is fixed at the other
end to the suail y at the point y' so that the said pulling strap or cord is wound up

page_text: on the circumferential path of the snail inwards by the time the strap or cord has
unwound as far as its point of attachment at p. This position, seen in Figure 7,
corresponds to the outer stroke or position from which the effective pull on the
strap a by the power piston can begin.
=
1
2
=
ย
2
1 now the strap a is drawn in the direction indicated by the arrow near it both
cord snails p must turn in the direction of the arrow, whereby the strap or cord a
unwinds from the snail 7 continually increasing the distance of its effective acting
point from centre of the countershaft r whilst on the other hand winds on to p
and thereby its effective acting point continually approaches nearer to the centre of
the said shaft. The middle position is shown, as before explained, in Figure 8.
It will be understood that the two cord snails correspond in their manner of
action to a bell crank lever, the arms of which change their lengths in the opposite
sense, so that if for instance at the beginning of the stroke the leverage
1
4.64 ✓100
the leverage at the end of the stroke is
The
9.28 23/100
final position of the straps or cords a and is shown in dotted lines, and after
reaching this position a backward revolution of the countershaft through 360°,
and of the shaft C through 720°, allows of the backward motion of the piston, and
the slackening of the said straps or cords to enable the one to be wound up on to
the snail and the other to be unwound from the snail p until the initial position
is reached. The previous winding up of one end of on the snail corresponds
to the unwinding of the other end from the snail which is thereby caused to turn
in the direction of the arrow. Inasmuch as the effective acting point of the
pulling device constantly recedes from the centre of the shaft the lever arm which at
first = gradually increases until it reaches its outermost position and maximum
value (= 100). By means of this change in the length of the lever arm the pro-
portionate leverage which as before shown was brought to the limits and
7'
1
4.64
2
19
:
1 4.64
again changed, because from the proportion
9.28
1
2
1
1
X
9.28
a proportion which is equal to
=
9.28
]
(100)
✓ 100)³
WC have
1
(namely
100 (100) ✓100).
3
4-64 4.64'
According to this it follows that under the above conditions the effective leverage
which causes the turning of the cord smail is 100 times less at the beginning than
at the end of the stroke. If therefore the pulling power of the motor, or the gas
pressure in the power cylinder is reduced to the hundredth part for example of the
initial pressure, a constantly uniform amount of power is still transmitted to the snail
shaft C by means of the above described apparatus.
In the snail r, which is arranged to make two complete revolutions (forwards and
backwards) the circumferential path must be exactly equal to that of the pulley p.
The proportions and sizes of the cord snails should be adapted to circumstances
and be calculated according to the greatest and least pressures that are to be
transmitted. The double cord snail may be replaced by a single one where
abnormal dimensions would not thereby be rendered necessary.
The form of the pulley or disc bodies as cord snails is preferable to that of the
cord drum, because they are easily adapted to suit the required purpose.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed 1 declare that what
I claim is :-
First. The improved apparatus for producing rotatory motion which consists of
pulleys, curved lever-like parts or snails operated by straps, cords, chains or the
like and transmitting motion during their forward movements, to the part to be
rotated, by means of ratchet gear, their backward movements for rewinding
up of the said straps, cords or chains being effected automatically, substantially
as described.

page_text: Second. The arrangement of the apparatus forming the subject of the first
claiming clause hereof in which the power applied to the pulling device is trans-
mitted thereto by means of foot treadles TT which enables the weight of the
body to be utilized for effecting the rotation of the part to be driven, substantially
as described.
Third. The arrangement of the apparatus forming the subject of the first
claiming clause hereof. in which the circular cord pulleys on the shaft or other
part to be driven are replaced by curved lever-like parts or sunils from which
the pulling devices run off tangentially, so that when using a motor operated by
variable pressure, a constant driving effect is obtained on the shaft or other part to
be driven, substantially as described.
WATCH TRAs own any of an 10.
H.
GANSWINDT,
Per W. H. Beck,
115, Cannon Street, London, Agent.
H. GANSWINDT,
Per W. H. Beck,
115, Cannon Street, London, Agent.