Improvements in Safety Attachments and Brakes for Hoists.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in Safety Attachments and Brakes for Hoists.
I, CARL KUNTZE, of Zawodzie, near Kattowitz, Upper Silesia, Engineer, do
bereby declare the nature of this invention to be as follows :—
The cbject of the present invention is to construct a safety attachment and brake
for hoists which shall be free from concussion when brought into use.
It consists
in the use of serrated blades for gripping or penetrating the guides of the hoi-t
when the rope breaks to bring the cage to a standstill without shock.
The accompanying drawing shows a safety attachment and brake constructed in
accordance with this invention.
Fig. 1 shows it attached to the cage of a hoist.
Figs. 2 to 5 show details of construction.
In the drawings a is the rope and the guide. On the rope a breaking the
springs c are brought into action and force the pins d downwards. The levers e
are turned accordingly imparting an upward movement to the arms e¹ and thereby
simultaneously bringing the serrated or saw blades into contact with the guide .
The serrated or saw blades cut grooves in the guide b which is made of wood and
the resistance which they offer in this operation gradually diminishes the force of
the descent of the cage. By means of this safety brake the force or motive power
of the cage is absorbed through the work of the saws a feature which distinguishes
the present invention from all appliances heretofore used for the same purpose.
Another distinguishing feature in this safety brake is the oblique position of the
cutting surfaces of the serrated blades. The blade edges i.e. the entire front
cutting surface of the blades is not made parallel to the guide b but forms an angle
with the same. By this means the saw blades are gradually brought into contact
with the guides the gradual absorption of the energy and weight of the cage is
affected and the latter brought to a standstill without concussion.
advantage arising from the oblique position of the serrated surfaces of the blades
consists in the case with which the bits cut by the saws fall down and can be
removed.
A further
It is obvious that the number and dimensions of the serrated or saw blades may
be varied according to the load to be carried by the cage and the nature of its
construction and that in a brake of this description the spaces between the blades
and the depth to which they penetrate the groove must be capable of being
regulated. This can be easily attained by the arrangement (Fig. 3) by means of
which the serrated or saw blades can be adjusted at any distance from each other
and the distance determined in a very simple manner.
The advantages which the present safety brake possesses over all other methods
and particularly over the well known knife clutch arrangement are of an important
nature and may be described as follows:-
As previously stated the stopping of the cage of the hoist is effected gradually
and without concussion. The guide is not torn or seriously damaged as was
formerly the case as soon as the brake began to work particularly when the wood
was dry but only slight cuts are made by the serrated blades in the guide which
by no means render it unfit for further use. The greatest drawback however of
of the former safety appliances or brakes consists in the inability of the parts which
catch in the guide or groove-particularly the knife shaped clutches-to cut throug b

page_text: knots therein and consequently there has arisen either a sudden shock or the parts
which supply the brake power have been destroyed.
Dated this 25th day of April 1895
1, CARL KUNTZE, of Zawodzie, near Kattowitz, Upper Silesia, 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 :-
The object of the present invention is to construct a safety attachment and
brake for hoists which shall be free from concussion when brought into use. It
consists in the use of serrated blades for gripping or penetrating the guides of the
hoist when the rope breaks to bring the cage to a standstill without shock.
The drawing left with the Provisional Specification shows a safety attachment
and brake constructed in accordance with this invention.
Fig. 1 shows it attached to the cage of a hoist.
Figs. 2 to 5 show details of construction.
In the drawings a is the rope and the guide. Should the rope a break the
springs are brought into action and force the pins d downwards. The levers e are
turned accordingly imparting an upward movement to the arms e¹ thereby
simultaneously bringing the serrated or saw blades g into contact with the guide .
The serrated or saw blades cut grooves in the guides which is made of wood and
the resistance which they offer in this operation gradually diminishes the force of
the descent of the cage. By means of this safety brake the force or motive power
of the cage is absorbed through the work of the saws a feature which distinguishes
the present invention from all appliances heretofore used for the same purpose.
Another distinguishing feature in this safety brake is the oblique position of the
cutting surfaces of the serrated blades. The blade edges i.e. the entire front cutting
surface of the blades are not placed parallel to the guide but form an angle with
By this means the serrated or saw blades are gradually brought into
contact with the guides the gradual absorption of the energy and weight of the
cage is eflected and the latter brought to a standstill without concussion. A further
advantage arising from the oblique position of the serrated surface of the blades
consists in the ease with which the bits cut out thereby fall down and can be
removed.
the same.
It is obvious that the number and dimensions of the serrated or saw blades may
be varied according to the load to be carried by the cage and the nature of its
construction and that in a brake of this description the spaces between the blades
and the depth to which they penetrate the groove must be capable of being
regulated. This can be easily attained by the arrangement (Fig. 3) by means of
which the serrated or saw blades can be adjusted at any distance from each other
and the distance determined in a very simple manner. A nut or sleeve is screwed
over an arm or link pivoted on the shaft by which the bearing is moved to or from
the centre of the cage.
The advantages which the present safety brake possesses over other methods and
particularly over the well known knife clutch arrangement are of an important
nature and may be described as follows.-
As previously stated the stopping of the cage of the hoist is effected gradually
and without concussion. The guide is not torn or seriously damaged as was
formerly the case as soon as the brake began to work particularly when the wood
was dry but only slight cuts are made by the serrated blades in the guide which

page_text: by no means render it unfit for further use. The greatest drawback however of
the former safety appliances or brakes consists in the inability of the parts which
catch in the guide or groove-particularly the knife-shaped clutches-to cut
through knots therein and consequently there has arisen either a sudden shock or
the parts which supply the brake power have been destroyed.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what I
claim is.
(1.) A. catch brake for hoists capable of acting without concussion constructed
with adjustable serrated blades which engage with the guides whereby when
brought into operation the descending force or weight of the cage is gradually
absorbed substantially as described.
(2.) In a brake for hoists such as described in Claim 1 the adjustment of the
serrated blades g so that the front working edge forms an angle with the guide b
for the purpose of allowing the blades to come gradually into operation and
facilitating the removal of the bits of wood from the cuts.
(3.) A brake for hoists having the several parts constructed and arranged in
combination substantially as described and shewn.
Dated this 21st day of January 1896.
WM. P. THOMPSON & Co.