Improvements in and relating to Pulley Blocks and Tackle.
Year: 1892

page_text: Date of Application, 19th Nov., 1892-Accepted, 4th Feb., 1893
COMPLETE SPECIFICATION.
Improvements in and relating to Pulley Blocks and Tackle.
I, MARC PIERRE EMANUEL LÉTANG, of 21 Boulevard Poissoniere, Paris, in
the Republic of France, 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 :-
My invention relates to improvements in the arrangement or construction of
pulley blocks and tackle provided with an automatic brake.
The said improvements simplify the construction and ensure the operation of
these apparatus under all circumstances which may occur. They limit the mov>
ment of the rope employed to a single direction at least whenever the action of the
same is prevented by means of a clamping device which can be operated at will
and which also forms part of my invention.
To render these improvements properly understood I will now proceed to describe
the same with reference to the accompanying drawings, which represent by way of
example some kinds of my brake-pulley blocks and tackle.
In all the figures of these drawings corresponding parts are designated by similar
letters of reference.
A brake pulley block constructed according to my said invention comprises a
frame and a rocking beam.
In appearance and construction the frame (Figure 1) is similar to that of a simple
pulley. This frame carries at one of its extremities a suspension hook and has at
its two faces a certain number of holes.
At about one-third of its length from below is the hole O designed for the passage
of the cross-piece upon which the rocking beam oscillates. Above this hole is
another hole K designed for the passage of a cross-piece constituting one of the
blocks of the pulley. At the lower part is pierced the hole M the object of which
will be explained in the description of the improved tackle.
The rocking beam (Figure 2) is composed of two similar cheeks, only one of
which is represented; these checks are rigidly connected with one another by
cross-pieces, one of which, passing through C¹ carries a ring Z (Figure 3). These
cross-pieces are fixed at each end of the rocking beam in the holes C and C¹ in
such a manner that they leave between the two cheeks a sufficient space for the
sheaves which they are to carry.
These sheaves L and L', mounted upon axes the extremities of which are placed
in the holes D and D' and in corresponding holes in the other cheek, do not present
any characteristic feature.
Near the centre of figure of the rocking beam is the hole O designed for the
passage of the axis common to the frame and rocking beam and upon which the
latter can oscillate.
In proximity to the hole are two holes E and E¹ designed to support the two
cross-pieces which constitute the second block of the automatic brake.
The union of the frame and rocking beam is effected by means of an axis
traversing successively the holes O in the frame and in the rocking beam. The
apparatus has then the appearance represented in Figure 3, apart from the sheave
mounted at M and any device underneath.
To properly understand the operation of this particular arrangement it is
necessary to consider the path followed by the rope, which moves directly from
the sheath L on to the sheave L', passing between the cross-pieces K and E E¹
which constitute the jaws between which the rope will be clamped.
If I now suppose a weight or load is attached to the part p of the rope tho

page_text: corresponding part of the rocking beam will be lowered. Under these circum-
stances the cross-pieces E E situated on the other side of the point O rise
towards the fixed cross-piece, the rope is clamped at this point with a force pro-
portional to the lengths of the lever arms, and the weight or load is rendered
immovable.
The arrangement is such that the clamping will be sufficiently energetic for
effecting the complete stoppage of the rope.
If now a traction is exerted upon the part of the rope and this traction is
greater than that exerted upon the part the rocking beam will oscillate in the
opposite direction to that of the preceding oscillation, the cross-pieces E E¹
recede from the cross-piece K, and the brake thus releases the rope which will
be free to move from p to p¹.
I suppose that the parts p p of the rope leaving the pulley are practically
parallel and that the forces applied thereto act in the same direction, as shown
in Figure 3. .
However the movement of the rope in the two directions may be permitted by
exerting through the medium of the ring % upon the cross-piece C₁a sufficient.
traction to prevent the rocking beam from oscillating towards p so that the dis-
engagement or release of the rope will be optional.
It is evident that, by connecting the frame with the rocking beam so as to
prevent any oscillation of the latter, I can prevent the operation of the automatic
brake, and the brake pulley block then acts like an ordinary pulley block.
By modifying the positions of the sheaves L and L' relatively to the axis O of
the rocking beam, I may obtain a pulley block adapted to operate when the ends
of the rope are at about an angle of 90 degrees at their passage into and from the
apparatus. Such an arrangement is represented in Figure 6.
Figure 4 represents the frame and. Figure 5 the rocking bean of this special.
arrangement.
The frame (Figure 4), for enabling the apparatus to operate properly, must be
fixed rigidly so as to be immovable. For this purpose I have provided holes for
the passage of fixing screws. At O is the axis upon which the rocking beam can
oscillate; at K is the cross piece constituting one of the clamping jaws or blocks of
the brake.
The rocking beam (Figure 5) has at a hole for the passage of the axis of
oscillation, at D D' holes for the axis of the sheaves L L¹, and at E E¹ the holes
for the cross-pieces which constitute the second clamping jaw or block of the brake;
below is a slot B in which the part I fixed to the frame passes and can move
freely.
Figure 6 represents the apparatus mounted and the path followed by the rope,
which moves directly from the sheave L to the sheave L, passing between the
cross-pieces K and E E', and also the direction of the ends which leave a similar
pulley block.
The operation takes place in the same manner as that of the pulley block repre-
sented in Figure 3. The disengaging device placed on a prolongation Z of the
rocking beam is operated and acts also in a similar manner.
The brake tackle comprises, not the combination, but the union of an ordinary
tackle and a brake pulley in the same frame. Each of the two parts retains its
independent operation.
Figure 3 shows how this adjunction is effected, particularly from the point of
view of the stability of the apparatus.
The hole M in the frame (Figures 1 and 3) is designed to be traversed by an
axis bearing with each of its extremities upon one and the other of the cheeks.
This axis carries the number of sheaves less one, which the tackle is to have. The
position of this axis and consequently that of the hole M is such that the oscillation
of the whole apparatus, which takes place in each stoppage of the brake, will be
reduced as much as practicable. With this object it is fixed to the left of the
large axis in Figures 1 and 3.

page_text: The operation of the apparatus thus constructed is as follows:-
The rope is first wound upon the tackle to which is fixed the weight and upon
the sheaves placed at the base of the frame upon the axis M exactly in the same
manner as if the two systems of sheaves which constitute an ordinary tackle had to
be coupled. The last part of the rope, coming from the tackle to which the weight
is fixed, passes first on to the sheave L, then directly on to the sheave L' following
the path represented in Figure 3 in such a manner that the apparatus has all the
properties of ordinary tackle and that the operation of the automatic brake takes
place in the same manner as in the case of a simple brake pulley block.
This adjunction, being independent of the form of the rocking beam, can also be
combined with the arrangement represented in Figure 6 or with any other similar
arrangement.
It is evident that the form or the constitution of the above-described devices may
be varied according to the form, nature and constitution of the pulleys, cables, belts
or the like which they may have to clamp.
The movements of the rocking beam cause the approach or separation of the jaws
or blocks of the brake may be effected in numerous ways for example by means of
connecting rods, eccentrics or tie-rods of any kind.
Figure 7 represents one of these arrangements in which the movement of the
rocking beam is transmitted to the jaw through the medium of the connecting rod D²
which terminates in an eccentric collar surrounding the eccentric disc E³ which is
fixed upon the axis O firmly united with the rocking beam.
In the apparatus herein before described provision may be made for the clamping
to take place laterally as well as vertically. Figure 8 shows an arrangement of
this kind in transverse section.
A and A2 are the two cheeks of the frame B' B are the cheeks of the rocking
beam. A cross piece H represented in Figure 9 is fixed with each of its
extremities to each of the cheeks A1 and A2.
In the rectangular space which this cross-piece leaves in the middle is arranged
the small axis N. Upon the latter oscillate, like scissors, the rods m and m¹ upon
which are fixed the blocks k k¹. At the other extremity of the rods m and m¹ are
pivoted the two parts n and n¹ which are articulated together at f. The two
checks B and B of the rocking beam are united by the cross-piece G, and the
middle part of this cross-piece is connected to the point f by a ring i. Owing to
this arrangement, when the rocking beam is lowered this ring exerts a traction upon
the articulation of the parts n and n' which act in their turn upon the parts mand m³,
thereby causing the approach of the blocks k and k¹ and the clamping of the rope,
while the reverse movement of the rocking beam causes the release of the brake.
Figures 10, 11 and 12 represent an arrangement of a brake pulley block in which
the cord for effecting the disengagement is dispensed with.
This
The rocking beam, always constituted by two similar checks, between which the
sheaves L and L' are arranged, has articulated at a, at one of its extremities, a
part a', Figures 11 and 12, presenting more or less the shape of a cross.
part a possesses at its lower end an eye or hole through which passes the
end p of the suspension rope coming from the sheave L' before passing to the
hand of the operator and at its extremity opposite the articulation a it has a
notch behind an inclined plane e'. The notch e, on the part pl of the rope
being pulled to the right, bears upon a pin 6 of the frame when the rocking
beam, is in the open position (Figure 10)...
Under these circumstances the rocking beam, fixed at two points, is immovable
and remains in the open position. For rendering it movable it is necessary to pull
the part p' of the rope to the left, with the object of releasing the part a',
The form of this part and the position of the pin b may be varied, the latter may
be placed above the rocking beam instead of putting it below or let the extremity
of the part a' butt against the upper part of the frame, a suitable form being given
to it for each position. It is also possible to place the pin b directly upon the
rocking beam and the part a' upon the frame to which it may be connected by its

page_text: axis of oscillation. All these arrangements may moreover be such as to operate
either in the general plane of the pulley block or in a plane perpendicular to the
latter.
Figures 13 and 14 show an arrangement which enables the apparatus to operate
when the part p of the rope which carries the load passes in any direction from the
vertical position to that of a right angle through the arc a (Figures 4 and 5); this
arrangement consists in placing the sheaves L and L' at an unequal distance
relatively to the axis of oscillation O of the rocking beam that from which passes
the part of the rope which supports the load being longer than the other.
Moreover the line DO D¹ from centre to centre is a broken line, and the
oscillation of the rocking beam is limited by means of a slot B or in any other
appropriate manner.
Figure 15 shows a particular arrangement of the rocking beam in which the
sheaves L and L' are parallel to one another and nearly side by side instead of
being one before the other in the same plane. In this arrangement (Figure 6) the
frame has at its upper part a suspension hook X and a cross piece Y whose central
shoulder pierced with a hole serves as an axis of oscillation O for the rocking beam.
The lower part of the frame is pierced with two holes for the passage of the
guides and ¹ of the secondary frames Q and Q₁ of the same form but one of
which, Q (Figure 16) carries a ring 9 at its lower part. These two secondary
frames are articulated to the rocking beam and receive each a sheave for the
passage of the rope. The rocking beam employed is very short, and one of its
extremities carries a ring Z (Figures 15 and 17) for the cord employed in this case
for the disengagement.
Above one of the sheaves is a brake block K' (Figures 15 and 18) designed to
clamp the rope between it and the sheave to which it corresponds. This block is
fixed upon the principal frame.
To increase the clamping force, one of the ends of the rope fixed to the ring g
passes over the first sheave of an ordinary tackle (Figure 15) then passes back
over the sheave L of the frame which carries the said ring, to be conducted thence
over the second sheave of the ordinary tackle and finally over the sheave L¹
between it and the block K¹ from which it passes freely. To the ordinary tackle
provided with a hook, is attached the load to be raised.
My brake pulley block thus arranged operates in the following manner.
When the free part p¹ of the rope is pulled the rocking beam is lowered, and at
the same time the sheave L' of the frame Q'recedes from the block K' until the
rocking beam acted upon by the frame Q, oscillates in the opposite direction and
until owing to this fact, the rope is clamped between the sheave L' and the fixed
block K¹. The clamping force is such as to stop the rope and to discontinue the
descent of the load when it is left to itself.
For releasing the suspension rope it is enough to exert upon the rocking beam,
by means of the cord attached to Z, a sufficient traction for moving it back to the
open position.
In lieu of securing the suspension rope to the ring 9 I may for example give the
arm of the rocking beam on the side of this ring a greater length than that which
carries the other frame.
This arrangement of the brake tackle may itself be modified as represented in
Figure 19, which shows a guide sheave R fixed to the principal frame and placed
perpendicular to the sheaves L and L'..
This modification has for its object to wind up the suspension rope in the same
manner as in the case of the brake tackle shown in Figure 15 and to transform the
apparatus in this manner into an automatic brake pulley block of a reduced bulk,
the operation of which is effected in a similar manner.
It is evident that the number of sheaves employed either in the tackle or in the
pulley block constructed according to this modification is not. limited. If the
number is even I may either distribute a suitable number of the sheaves in each of
the frames so that the clamping and release are effected properly, or have them

page_text: the loads symmetrically with regard to the point of attachment, and the said
eccentric arrangement of the axis of these sheaves in combination with the rocking
beam and the clamping and stop jaws, as herein specified with reference to the
accompanying drawings.
4. The arrangement of the pulley block comprising a rocking beam, two
sheaves L and L', a fixed frame, the whole arranged and operating in the manner
described with reference to Figure 6 of the accompanying drawings and with
the object of enabling the traction to be exerted at any angle relatively to the
direction of the load to be raised.
5. In pulleys, tackle and the like having a rocking beam, the special arrangement
of the jaws represented in Figures 7 and 8 of the drawings, the said jaws being set
in action either by an eccentric (Figure 7) or by a system of articulated rods
(Figure 8) or in any other appropriate manner and designed to effect the clamping
of the rope, as herein described.
6. In brake pulley blocks and automatic brake tackle the arrangement of a
clamping part in combination with a pin with the object of effecting the
clamping and release of the rocking beam with sheaves L L' by the simple
displacement of the part pl of the suspension rope, that is to say without the
intervention of a special rope for the disengagement, as herein described with
reference to Figures 10, 11 and 12 of the accompanying drawing.
7. In brake pulley blocks and automatic brake tackle the special arrangement of
the rocking bean with sheaves L L enabling the suspension rope of the said
apparatus to operate in any direction as herein described with reference to
Figures 13 and 14 of the accompanying drawings.
8. In brake pulley blocks and automatic brake tackle the arrangement of the
sheaves L and L side by side, that is to say parallel to each other through the
medium either of two secondary frames Q Q articulated to a rocking beam
perpendicular to their plane, or of two levers T T¹ performing at the same time
the part of a rocking beam, the clamping being effected either directly between
one or more sheaves and the rim of one or more sheaves, or between two blocks
actuated directly or indirectly by the movement of the rocking beam or levers, as
herein described with reference to Figures 15, 16, 17, 18, 20, 21 and 22 of the
accompanying drawings.
9. The arrangement of a supplementary sheave R, perpendicular to the movable
sheaves L L placed side by side and serving as a guide sheave for permitting of a
particular winding of the rope designed to transform the brake tackle shown in
Figure 15 into a brake pulley block of reduced bulk as herein described with
reference to Figure 19 of the accompanying drawings.
Dated this 10th dow of November 1802
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.

page_text: carried by the principal frame by inserting them between the two movable frames ;
this latter arrangement is immaterial from the point of view of the operation of the
apparatus.
Inversely, as the apparatus operates in all cases as if the rope were fixed to the
movable frames, it is possible to dispense with one of the sheaves, by attaching one
extremity of the rope to the rocking beam either directly or through the medium
of a part adapted for this purpose.
Figures 20, 21 and 22 show an arrangement which is designed to obviate the
lateral movement which the rocking lever may impart to the secondary frames.
This arrangement consists in substituting for the rocking beam a system of
levers T and T (Figures 11, 12 and 13) carrying each a sheave L L' and actuating
one another mutually in such a manner that when one of them is raised the other
is lowered an equal distance and vice versa. This movement enables the clamping
of the suspension rope to be effected either between the rim of one of the sheaves
and the block, or between two brake jaws, or else enabling the rope to be clamped
upon the whole of the sheaves. The release is then effected by exerting a traction
from the outside upon the levers so as to bring them to the open position.
It will therefore be seen that the aforesaid two levers oscillate at t t upon the
principal frame and one of them, T', carries a pin engaging by means of its.
extremity with the grooved in the other lever T. The lever T₁ carries the ring
designed to attach the rope for the disengagement and the lever T carries a ring
designed to attach the suspension rope. Above the sheave L' is placed a block K'
fixed to the frame (Figure 20). The suspension rope extending from the ring 9
passes over the first sheave of the ordinary tackle then rises to move over the
sheave L, next descends on to the second sheave of the ordinary tackle and finally
passes over the sheave L' between the block K' and the sheave L' whence it leaves.
freely in order to be actuated by the operator.
It will be observed that in the arrangements herein before described, and also in
those which are the corollaries of the same, the position of the centre of oscillation
of the rocking beam relatively to the sheaves may be varied in any desired manner
according to the object to be realized. It is in fact evident that by lengthening the
lever arm of the rocking beam in one or the other direction, I obtain a more
powerful clamping action or an easier releasing action. It may also be advantageous
to displace this centre of oscillation relatively to the line which joins the centres of
the axes of the two sheaves.
In all my arrangements of pulley blocks with an automatic brake I may also
provide for several ropes to be used in the same apparatus, for this purpose it.
suffices to give the axes of rotation a sufficient length for placing side by side a
number of sheaves equal to the number of the ropes employed, and to place between
the latter metallic strips or any other devices which ensure their direction in the
passage through the apparatus.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In pulleys, tackle and the like the special arrangement of a rocking beam
carrying only two sheaves over which passes freely a rope moving directly from
one to the other, the said rocking beam oscillating in one direction or in the other
according as a greater traction is exerted upon one or the other part of the rope.
2. In pulleys tackle and the like the arrangement of the oscillating beam
specified in the first claim in combination with one or the other kind of jaws
represented in the drawing, with the object of effecting the clamping and
consequently the stoppage of the rope by the utilization of the movement produced,.
substantially as described.
3. In tackle, with the object of diminishing or obviating the oscillations produced
in each upward movement and in each stoppage of the weight, the eccentric
arrangement of the axis of the sheaves of the tackle with the object of distributing.