Improvements in Automatic Grip Pulleys.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in Automatic Grip Pulleys.
I, NICHOLAS GHERASSIMOFF, of 36 Troitzkaya Street, St. Petersburg, Russia,
Second Captain, do hereby declare the nature of this invention to be as
follows:-
This invention relates to pulleys for the transmission of power by means of
ropes or it may be cords, cables, chains or the like.
The periphery of the pulley carries grippers and the rope as it passes over the
pulley lies between the grippers.
The grippers are brought into action by stationary guide surfaces; there are
rollers on the outer ends of the grippers which run in grooves in the guide surfaces
and these grooves are so formed and of such a depth that at the proper time they
cause the grippers to approach and to nip the rope between them at their inner
ends.
The grippers are carried by radial projections at the periphery of the pulley
and on these projections other guides cause the grippers to travel radially a short
distance, the object of this is that the rope may not be bent at the place where the
grippers operate but may, whilst held by the grippers, travel in a direction
tangential to the periphery of the pulley. The rope will consequently wear much
longer than it otherwise would.
Thus the grippers are moveable in two ways upon the pulley which carries them,
they can move parallel to the axis of the pulley and they can also move radially.
The pulley may consist of two hoops each with radial spokes; the hoops are
connected by cross pieces and the radial spokes projecting through the hoops serve
to carry the grippers.
Means are provided for accurately adjusting the distance between the guide
surfaces so that the grippers may be made to approach each other sufficiently to
nip and hold the rope without exposing it to undue pressure. Screws with
indicating dials and pointers may be employed to effect this adjustment.
The arrangement may be simplified by having one only of the grippers of cach
pair moveable.
The grippers may be made double to take two ropes side by side. The grip
pulley can also be provided with two or more sets of grippers at different distances
from the centre and so several ropes may be worked on the same pulley.
For working at high speeds and to avoid risk of displacement, the grippers. may
be locked upon the radial projections and unlocked at the time when the guide
surfaces come into operation.
Dated this 18th day of June 1895.
CARPMAEL & Co.,
Agents for the Applicant.

page_text: I, NICHOLAS GHERASSIMOFF, of 36 Troitzkaya Street, St. Petersburg, Russia,
Second Captain, 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 has for its object in the transmission of motive power by means
of cords cables or belts to substitute an automatic grip for friction upon the rim of
pulley, and for this object I have invented a system of pulleys with automatic
grippers.
a
This system of gripping pulley is applicable to all mechanical transmission of
motive power, even by means of belts, the action of the pulley being based upon
the friction between the grips and the transmitting means (cord, chain, strap, &c.).
The principle of my cord grips is as follows:-
Let us suppose a surface A Figure 1 moving in the direction shown by the arrow
between two stationary surfaces B B'. The surface A carries two cord grips d f c
and dfc mounted upon two pins ff in such a manner that they can move
independently the one to the other in a direction perpendicular to that of the
surface A. Springs in the cord grips compel the ends c and c¹ to follow the guide
grooves formed in the surfaces B and B', consequently the ends d and d' will be
compelled to describe curves parallel to the direction of the grooves in the
surfaces B B¹. Now by selecting this direction suitably, any required pressure by
the cord grips upon the cord S placed between the ends d and d is obtained. If
the surface A is round, a pulley on my system is obtained.
The details of construction of the cord grip are shown in Figures 2, 3, 4, 5, 6
and 7.
The cord grip consists in a plate a of steel, iron or cast iron (according to the
required degree of resistance) having at its centre a rectangular hole by means
of which the cord grip is mounted upon the pin or bolt g fixed to the rim of the
pulley; the plate a is provided at one end with a caoutchouc facing and at the
other end with a cast iron roller i.
Figure 2 is a plan of the cord grip, Figure 3 is a longitudinal section on the
line C-D of Figure 2. It will be seen in Figure 2 that a spring e is placed in
the cavity b, which bears on one side against the wall of the cavity b and on the
other against a plate K (shown separately in Figure 4). This plate K is provided
with small projections K' K' which guide it in the grooves m no formed in the
inner walls of the cavity b. The plate K insures a regular pressure upon the
projection g independently of the more or less elevated position of the cord grip
upon the projection.
The arrangement shown in Figure 5 which is a transverse section and Figure 6
which is an elevation partly in section shows that the cord grips can be moved up
and down upon the pins g by means of suspension rods P.P the upper horizontally
curved portion of which bears against a guide bar q r Figure 9 at the part of the
circumference where the cord grips should bear upon the rim of the pulley or that
curved portion of each rod p rides upon another guide bar st in the intermediate
portion of the circumference traversed by the ends of the rods p. The necessity
for displacing the cord grips along the pins g in the case of transmission by
metallic cables is explained by the following considerations.
In order to prevent too rapid wear of the cables they should not be subjected at
the same time to the action of the forces of traction and flexion. By causing the
cord grips to act upon the cable at the points u and v Figure 8 it is clear that the
mobility of the cord grips upon the pins allows the cable to traverse a certain

page_text: distance u and ev¹ in a direction tangential to the pulleys A A' whereas fixed
cord grips would force the cable to follow the curvature of the pulleys.
In the case of transmission by means of cords &c. when the mobility of the cord
grips is not a necessity, the cord grips may be made stationary upon the pin by
means of a transverse peg a Figure 7 fixed in a corresponding hole formed in the
pin g.
Figure 7 shows an arrangement which allows the end of the plate a to be lifted
out of contact with the cord, which is useful for enabling the cord to be easily
placed upon the pulley between the cord grips. For this object the end a¹ is
connected to the plate a by means of a hinge which. allows this end to be raised
into the position shown in dots in Figure 7.
The pulley A does not differ from ordinary pulleys except that it is provided
with pins or projections g which may simply be prolongations of the spokes through
the rim of the pulley. The construction of the pulley is shown in elevation and
plan in Figures 14 and 15 as well as in Figure 5 which is a transverse section and
Figure 6 which is an elevation partly in section. It will be seen that the pulley
has two parallel rims E E' connected together by means of transverse bars F F¹
through which the pins g pass.
The pedestal or support for the pulley carries two fixed cast iron guide rings H
the shape and construction of which are shown in Figure 6 which is a vertical
section Figure 9 which is a front view, Figure 10 which is a rear view and
Figure 11 which is a general view. Figure 12 shows a regulating dial and
Figure 13 the shape of the groove at the place where pressure is applied. The
width of this groove Figure 6 is greater by three to four millimetres than that of
the roller of the cord grip and at the spot at which the cord grip should
commence its action the groove takes the direction of a tangent to the circumference
of the pulley, its depth is lessened by the amount necessary for gripping in the
direction of the distance between the cord grips upon the pulley; afterwards the
groove returns to its normal depth.
One of the guide rings H Figure 6 is permanently fixed to the frame or
support K; the opposite ring H is moveable in such a manner that the distance
between the corresponding cord grips may be regulated within certain limits. For
this object the support K is provided with three uniformly threaded openings K'
to receive the three screws L which end in discs lodged in the corresponding
holes (Figure 10) in the guide ring H. The holes are contracted laterally in
such a manner that on turning the guide ring through a small angle in the direction
of the travel of the cord, this ring becomes fast with the screw L and consequently
The end of each
may be brought nearer to or further from the support K.
screw L projecting from the support is provided with a crank handle and with a
pointer moving over a dial M Figure 12 fixed to the support and marked out
into divisions showing the distances between the cord grips at the moment of
applying pressure. The thread of the screw L should be such that one turn of
the crank is sufficient to vary the pressure from the minimum to a distance greater
than that of the diameter of the cord. By this arrangement the degree of
pressure may be regulated with the utmost precision, and one turn of the crank is
sufficient to cause the friction of the cord to cease and consequently the transmission
of power. The frame of the support extends somewhat beyond the wheels and
rings Figure 11 and its legs are connected together by means of cross bars which
do not allow them to yield under the gripping action. The frame is of ordinary
construction, except that it is provided with a curved casing N formed of wooden
planks which protects and guides the cable. For pulleys of small size and for
hempen cords the details of the arrangement may be simplified.
If the cable be allowed to bend around a portion of the circumference, the cord
grips may be fixed in place by means of a pin which simplifies construction.
A single series of cord grips may be employed the other being replaced by bosses
or pins fixed upon the rim of the pulley as in Figure 16, but in this case the
support will be exposed to lateral pressure and the rolling friction will be replaced

page_text: by sliding friction; the working of the arrangement will therefore be less
advantageous.
For a two cable system the arrangement shown in Figure 17 may advantageously
be employed. The middle pin may be a simple boss upon the rim or the
continuation of the spokes of the pulley without the cord grip. For four cables
the construction shown in Figure 18 may be employed that is to say, with the cables
arranged in two tiers the upper cable being the lighter.
The guide rings may be immoveable if the construction of the cord grips
shown in Figure 7 is used.
In lifts the pulleys should have the smallest possible diameter. When chains
are employed the chain grips should be arranged upon the pulley in such a manner
that they gear with the chains in the same position of the links.
My system of pulleys with automatic cord grips has the following advantages
when compared with common pulleys.
1. The weight and the cost of construction are less for the same force
transmitted.
2. Owing to the favourable conditions under which the work is done, the life of
the transmission parts is much lengthened.
3. Advantages in working such as facility in raising and arranging the cords
chains and the like (which are not stretched) upon the pulleys; the possibility of
stopping the transmission of movement at any time and of applying the power of
the engine to any other object; the possibility of increasing the speed of the
pulleys (the centrifugal force of the transmission having no effect); independence
of the work from any tendency of the cords to stretch and finally a greater result
thanks to the absence of loss of power due to slipping, friction, etc.
4. In lifts, this system gives a much greater power, and in towing chains may
replace cords.
When the speed of the pulleys has to be great centrifugal force will tend to press
the horizontal arms of the suspension rods Figure 6 on to the guide bars. In this
case I employ the construction shown in Figures 19, 20, 21, 22 and 23.
Figure 19 shows the shape of the groove or fixed guide which is interrupted at the
spot where pressure is applied and has a supplementary bar 1, 2, 3. The suspension
rod is forked and carries at its upper end a roller and at its lower end the prongs
of this rod are connected by a cross bar which is lodged in a corresponding
recess in the ping in which it is kept in an inclined position (see Figure 22) by
the pressure of a spring y. At the moment of pressure a projection z¹ on the
plate a of the cord grip acts against the spring y' and places the cross rod in a
perpendicular position (see Figure 23) in which position it can ascend freely along
the longitudinal groove 2 in the rod y Figure 20 which allows the roller of the
suspension rod to be raised to the bar 1, 2, 3 by the action of centrifugal force.
The part 2, 3 of this bar brings the roller back against the lower track and as the
pressure has ceased the projection 2' allows the spring y' to place the cross rod in
the inclined recess in the pin.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is
1. A pulley system for the transmission of motive power by means of cords
cables or chains characterised by the disposition of cord grips on both sides of the
cable and which are caused to press by two fixed guide surfaces.
2. The cord grips mounted upon pins or bolts fixed to the rim of the pulley and
capable of being moved in a direction transverse to the rim and radially along the
pins for the purpose specified.
3. The combination of the novel pulley with the fixed annular guide surfaces
producing the transverse movement of the cord grips and another series of guide
surfaces producing the radial movement of the cord grips along the pins upon the
pulley.

page_text: 4. The rim of the pulley consisting of two parallel rings connected together by
cross bars and provided with pins which are arranged in pairs at equal distances
apart and which are radial to the rim.
5. Accurate regulation and indication of the distance between the cord grips by
the variation of the position of one of the guide surfaces by means of screws
provided with pointers moving in front of a dial.
6. The combination of moveable and fixed cord grips for transmissions of minor
importance.
7. The combination of cord grips in several tiers for transmission of power by
means of four or other number of cables.
8. An arrangement of suspension rods for cord grips characterised by locking
and unlocking with the carrying pin to be used with pulleys rotating at great
speed.
וי.
101 1
1005
N. GHERASSIMOFF.