IMPROVEMENTS IN PULLEY BLOCKS
Year: 1874

page_text: LETTERS PATENT to Edwin Robert Wethered, of Woolwich, in the
County of Kent, Major, R.A., for the Invention of "IMPROVEMENTS
IN PULLEY BLOCKS."
Sealed the 1st June 1875, and dated the 24th December 1874.
PROVISIONAL SPECIFICATION left by the said Edwin Robert Wethered
at the Office of the Commissioners of Patents, with his Petition,
on the 24th December 1874.
I, EDWIN ROBERT Wethered, of Woolwich, in the County of Kent,.
Major, R.A., do hereby declare the nature of tho said Invention for
"IMPROVEMENTS IN PULLEY BLOCKS," to be as follows:-
The object of this Invention is firstly to provide a pulley block which
may either be used as an ordinary pulley for raising or lowering weights,
or as a friction pulley by which the rope which is passed over it may
have any desired amount of friction instantaneously applied to it to
retard or to stop its movement. For this purpose the pulley is mounted
upon an axis between a pair of side plates, and these plates at their
upper end have a pin passed through them to carry a loop by which the

page_text: pulley block may be suspended, below this pin a short vertical slot is
formed in cach of the side plates; through these slots is passed a pin to
each end of which two straps are connected, which pass downwards to
other pins similarly passing through slots in the side plates below the
pulley and on cach side of it. Upon each of these pins a small pulley is
mounted between the side plates, and by drawing the straps upwards
these small pulleys can be drawn against the rope, and compress it
against the pulley over which the rope is passed. In order to draw tho
straps upwards to thus put friction upon the rope, the upper pin to
which the straps are all connected and the pin which carries the
suspending hook are both embraced by an eccentric shaped loop, which
has a lever arm connected to it, and to the end of this arm a light cord
may be attached by which the arm can be drawn downwards. When
the arm is thus drawn downwards in order to lift the nipping pulleys, it
may also be brought against the side flanges of the pulloy in order to
act as a brake.
Other means than those above described may be adopted for drawing
the movable and fixed pulleys together to nip the rope between them.
In friction blocks constructed with three or more shoaves or pulleys,
over each of which the rope is led, I mount the pulleys between sido |
plates or checks. Some of the pulleys are mounted on pins fixed in the
checks, whilst one or more of the pulleys aro carried by pins passing
through slots in the checks, and are movable to and from the fixed
pulleys. When a weight is suspended from the rope or to the block the
movable pulleys will bo drawn towards the fixed pulleys and the ropo 1
will be nipped between them.
The degree to which the movable pulleys can approach the fixed
pulloys, and consequently the amount of friction put upon the rope may
bo controlled in various ways; the block may be suspended by a ring
connected to the side checks, or to the pin of one or other of the movable a
pulleys. If the block is suspended by a loop at the centre the block is
reversible, and weights may be lowered by either end of the rope.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edwin Robert Wethered in the Great Seal Patent
Office on the 24th June 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWIN
ROBERT WETHERED, of Woolwich, in the County of Kent, Major, R.A.,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of December, in the
year of our Lord One thousand eight hundred and seventy-four, in tho
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Edwin Robert Wethered, Her
special license that I, the said Edwin Robert Wethered, my executors,
administrators, and assigns, or such others as I, the said Edwin Robert
Wethered, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might make,
usc, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN PULLEY BLOCKS," upon the condition (amongst others)
that I, the said Edwin Robert Wethered, my executors or admini-
strators, by an instrument in writing under mý, or their, or one of
their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Edwin Robert Wethered, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in
and by the following statement thereof, that is to say :-
The object of this Invention is firstly to provide a pulley block which
may either be used as an ordinary pulley for raising or lowering weights,
or as a friction pulley by which the rope which is passed over it may
have any desired amount of friction instantaneously applied to it to
retard or to stop its movement. For this purpose the pulley is mounted
upon an axis between a pair of side plates, and these plates at their

page_text: upper end have a pin passed through them to carry a loop by which the
pulley block may be suspended. Below this pin a short vertical slot is
formed in each of the side plates; through these slots is passed a pin, to
each end of which two straps are connected, which pass downwards to
other pins similarly passing through slots in the side plates below the
pulley and on cach side of it. Upon each of these pins a small pulley is
mounted between the side plates, and by drawing the straps upwards
these small pulleys can be drawn against the rope, so as to compress it
against the pulley over which the rope is passed. In order to draw the
straps upwards to thus put friction upon the rope the upper pin to
which the straps are all connected has a lever arm connected to it, and
to the end of this arm a light cord may be attached by which the arm
can be drawn downwards.
Other means than those above described may be adopted for drawing
the moveable and fixed pulleys together to nip the rope between them.
In friction blocks constructed with three or more sheaves or pulleys
over each of which the rope is led, I mount the pulleys between side
plates or checks. Some of the pulleys are mounted on pins fixed in the
checks, whilst one or more of the pulleys are carried by pins passing
through slots in the checks, and are moveable to and from the fixed
pulleys. When a weight is suspended from the rope (or the block), the
moveable pulleys will be drawn towards the fixed pulleys, and the rope
will be nipped between them.
The degree to which the moveable pulley can approach the fixed
pulleys, and consequently the amount of friction put upon the rope may
be controlled in various ways, the block may be suspended by a ring
connected to the side checks or to the pin of one or other of the
moveable pulleys. If the block is suspended by a loop at the centre the
block is reversible, and weights may be lowered by either end of the
rope.

page_text: block by which one man can lower a very heavy weight or slack away
gradually under a heavy strain.
a is the main sheave mounted on an axis carried by the side checks ;
c represents a portion of a rope passed over the main sheave; dis the
cyc by which the block is suspended or made fast; d' is another similar
cyc; e, e, are the small nipping pulleys. Their axes e¹, e¹, are able to
slide in inclined slots 'in the side checks b, and they are also passed
through holes in the ends of the side straps ff. Through the other
ends of the strap f the ping is passed, and the same pin also passes
through the end of the lever ; i is one of the studs connecting the side
checks b, it serves also as a fulcrum for the lever h, so that when
pressure is applied to the outer end of this lever the pulleys e, e, aro
drawn inwards towards the axis of the main sheave a and the rope c is
nipped. The requisite pressure may be applied to the lever h in any
convenient manner, sometimes the hand of the workman may be directly
applied to it, in other cases a hand line may be attached to it, and again
it is sometimes convenient to pass the rope cover it after it leaves the
sheave a. A dotted line in the Drawing represents the direction in
which the rope is then led; Figure 3 is an elevation, and Figure 4 is a
section of a multiple shcave friction block constructed according to my
Invention, such a block is not applicable for raising weights but is
intended especially for lowering. a, a, are the side cheeks carrying
between them the sheaves b', b², b³, b', b³. The sheaves b', b², b¹, bº, aro
free simply to revolve, but the axis of the centre sheave is received
into guide slots in which it is able to slide from this axis, also the block
can be suspended by means of the hanger c; d is the rope rove over the
sheaves. This tackle forms an excellent fire escape when suspended
from a hook conveniently placed outside a window, the two free ends of
the rope are used alternately for lowering. The rope will always run,
but yet not so rapidly as to be dangerous even if uncontrolled, at the
same time the speed can with case be exactly controlled or the descent
may be arrested by maintaining a light hold of the ascending rope, and
this may be done either by the person who is going down, or by another
superintending the lowering. In some cases it may be convenient to
mako fast the rope, and attach the weight to be lowered to the block.
Figure 5 shows another form of sliding sheave friction pulley block.
This form is specially adapted for lowering ships' boats. The block is
fixed within the boat to the keel about midway of its length. Two ropes

page_text: as is shown rove through it. The boat hangs by these ropes; they
pass to blocks fixed to the boat near the two ends and so to the davits.
The ends or parts of the ropes above the block are during lowering
grasped and checked by the hands of the men by whom the lowering of
the boat is controlled.
Having thus described the nature of my said Invention and the
manner of performing the same, I would have it understood that I
claim,―
First. The construction of pulley blocks with instruments for checking
the rope by compressing it against the main sheave, substantially as
described in respect to Figures 1 and 2.
Second. The construction of friction pulley blocks with sliding sheaves
so arranged that the strain upon the rope causes it to become nipped or
held more or less tightly between the sheaves, substantially as described.
In witness whereof, I, the said Edwin Robert Wethered, have here.
unto set my hand and scal, this Twenty-third day of June, in
the year of our Lord One thousand eight hundred and seventy-
five.