IMPROVED SHEAVE PULLEY BLOCKS
Year: 1884

page_text: I, JAMES SWALWELL of Acre Street Battersea in the County of Surrey, Engineer,
and JOHN MOORE of South Stockton on Tees in the County of York, Engineer do
hereby declare the nature of our invention for IMPROVED SHEAVE PULLEY BLOCKS
to be as follows:-
Our invention is an improvement on ordinary sheave pulley blocks to be worked
by either a rope or a chain and consists in making such blocks self-sustaining by
applying a brake the action of such brake being regulated by part of the load and
also releasing such brake by every pull of the hand chain.
In carrying out our invention we use a central pin on which we place loosely a
collar which carries two eccentrics and a long arm or a long and short arm and
one or more eccentrics we also use a brake or brakes which swing loosely on the
cross-head above the sheave or sheaves which are placed on the eccentric or
eccentrics, the long arm carries two small rollers which act as guides for the rope
or chain. The whole is carried by a suitable frame.
In preparing a block with one sheave at the top and one at the bottom for
lifting one end of the rope or chain is attached to the short arm and then passed
down under the sheave of the bottom block Thence it is passed up and over the
sheave on the eccentric in the top block and down between the two small rollers on
the end of the long arm. To lift the load this end of the rope is pulled and the
load is then suspended part of the load being on the sheave on the eccentric on one
side of the central pin and the other part on the arm at the other side of the central
pin. It will thus be seen that the load may be balanced or any required degree of
pressure may be put upon the brake by lengthening or shortening the leverage of
the arm which carries one end of the rope that which we prefer being just sufficient
to safely sustain the load so that when the power is applied for lifting it will pull
the sheave from the brake and allow the weight to be lifted freely.
It will be seen that in blocks of more than one sheave the friction can be applied
to one or more of the sheaves as desired.
In a modification of our invention see figs 3 & 4 we use two eccentrics and a
long arm as before but instead of attaching one end of the rope to one of the
eccentrica or the short arm wo mount a pulley on each eccentric and attach the end
of the rope to the frame of the bottom block.
In preparing this block for lifting we attach one end of the rope to the frame of
the bottom block then carry the other end over one of the sheaves in the top block
then under the sheave in the bottom block thence over the other sheave under the
brake and down between the two small rollers on arm, the throw of the eccentrics
being such as to give the desired amount of pressure on the brake.
In some cases where a rope is used for lifting the break sheave may be corru-
gated to hold the rope and the friction applied to the sheave or a plain sheave may
be used and the friction applied to the rope as shown.

page_text: JAMES SWALWELL of Acre Street, Battersea, in the County of Surrey Engineer,
and JOHN MOORE of South Stockton-on-Tees, in the County of York, Engineer do
hereby declare the nature of our invention for IMPROVED SHEAVE PULLEY BLOCKS,
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement:―
Our invention is an improvement on ordinary sheave pulley blocks to be worked
by either a rope or a chain and consists in making such blocks self-sustaining by
applying a brake the action of such brake being regulated by part of the load, and
also releasing such brake by every pull of the hand chain.
In carrying out our invention we use a central pin on which we place loosely a
collar which carries two eccentrics and a long arm or a long and short arm and
one or more eccentrics, we also use a brake or brakes which swing loosely on the
cross-head above the sheave or sheaves which are placed on the eccentric or
eccentrics, the long arm carries two small rollers which act as guides for the rope
or chain. The whole is carried by a suitable frame.
In preparing a block with one sheave at the top and one at the bottom for
lifting, one end of the rope or chain is attached to the short arm and then passed
down under the sheave of the bottom block, thence it is passed up and over the
sheave on the eccentric in the top block and down between the two small rollers on
the end of the long arm. To lift the load this end of the rope is pulled and tho
load is then suspended part of the load being on the sheave on the eccentric on one
side of the central pin.
It will thus be seen that the load may be balanced or any required degree of
pressure may be put upon the brake by lengthening or shortening the leverago of
the arm which carries one end of the rope that which we prefer being just sufficient
to safely sustain the load so that when the power is applied for lifting it will pull
the sheave from the brake and allow the weight to be lifted freely.
It will be seen that in blocks of more than one sheave the friction can be applied
to one or more of the sheaves as desired.
In a modification of our invention see Fig we use two eccentrics and a long
arm as before but instead of attaching one end of the rope to one of the eccentrics
or the short arm we mount a pulley on each eccentric and attach the end of the
rope to the frame of the bottom block.
In preparing this block for lifting wo attach one end of the rope to the frame of
the bottom block then carry the other end over one of the sheaves in the top block
then under the sheave in the bottom block thence over the other sheaves under the
brake and down between the two small rollers on arm, the throw of the eccentrics
being such as to give the desired amount of pressure on the brake.
In some cases where a rope is used for lifting the brake sheave may be corru-
gated to hold the rope and the friction applied to the sheave or a plain sheave may
be used and the friction applied to the rope as shown.
When a chain is used the sheave may be made with sunken chambers to hold
the chain, and the friction applied to the sheave or a plain sheave may be used and
the friction applied to the chain.
In some cases we move the brake to the sheave instead of the sheave to the
brake and to effect this we swing on the cross-head or other convenient fulcrum
the long arm, with two eccentrics on one end and two small rollers on the other.
On one of the eccentrics we swing the brake and to the other we attach one end of

page_text: Second, making ordinary sheave blocks self-sustaining, by moving a brake or
brakes to a sheave or sheaves, by part of the load and from the same through a
lever by every pull on the hand chain or rope as in Figs 5 & 6.
Third, making lifting machinery self-sustaining by moving a brake to a friction
surface by part of the load and from the same through a lever by every pull on the
hand chain or rope.
We make the before mentioned claims substantially as herein described or any
mere modification thereof.
JAMES SWALWELL.
JOHN MOORE.