Year: 1885

page_text: I, ROBERT PIRIE, of 9, Woodville Road East, Cathaya, Cardiff, in the County
of Glamorgan, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention, which relates to automatically balanced cranes, consists in the
use, in connection with the crane, of a travelling counterweight, which is connected
to the main chain of the crane and is operated so as to counteract any tendency on
the part of the crane to be overturned by the strain exerted in raising or lowering
weights.
Extending backwards from the main body of the crane frame are rails or bars
which constitute a track or way for the travelling counterweight.
This track or way is curved upwards from the points at which it extends from
the main body of the frame of the crane-The counterweight is fitted with wheels
which rest on the rails or bars of the track or way-The working chain of the
crane, that is the chain by which weights are raised and lowered, is connected at
one end to the winding gear. Thence it is conducted over a pulley carried in
bearings in the jib towards the outer end thereof, and is passed below the pulley
of a pulley block, to which is fixed the hook by which the chain is attached to the
weights to be raised. Thence the chain is carried upwards and passed over a
pulley carried in bearings at the top or outer end of the jib. The chain is now
conducted back over the jib and is coupled to a cross-shaped frame and is connected
by chains or ropes to the travelling counterweight aforesaid.
To that end of the middle limb of the cross-shaped frame which is towards the
counterweight is attached a chain or rope which is passed over a guide pulley, or
pulleys carried in bearings at the top of the main frame of the crane. This last
mentioned chain or rope is secured to the lower end of the plunger of a ram
vertically arranged near the king post. Above the ram is a tank or reservoir for
the supply of water or other liquid to the cylinder of the ram with which it
communicates, the communication being controlled by a valve.
The main frame of the crane is pivotted to the king post at or near the top of
the latter and is capable of being tilted upon its pivot within narrow limits.
D
077

page_text: When the crane is put into operation to take a weight, the travelling counter-
weight is drawn backwards and upwards on the track or way above mentioned,
the plunger of the ram rises in the cylinder and no lifting strain is as yet exerted
on the weight attached to the working chain. When the counterweight has thus
been drawn to such a point, that the rear side of the crane becomes heavier than
the front, the main frame of the crane is tilted backwards, a plate is brought
into contact with a disc which is connected to the valve spindle, and the valve
is thereby closed. The liquid previously admitted to the cylinder, and now
remaining therein, is, by the closing of the valve, prevented from returning to
the tank or reservoir, and the further ascent of the plunger in the cylinder is
resisted by the liquid. The lifting strain is then exerted on the..weight to be
raised, and the strain which is taken by the crane is received vertically on the
king post of the now effectively counter balanced crane.
The closing of the valve of the ram may be effected in other ways than that
indicated.
W. LLOYD WISE,
Applicant's Agent.

page_text: Improvements in Automatically Balanced Cranes.
I, ROBERT PIRIE, of 9, Woodville Road East, Cathays, Cardiff, in the County of
Glamorgan, Engineer, do hereby declare the nature of this invention, and in what
manner the saine is to be performed, to be particularly described and ascertained
in and by the following statement :—
This invention, which relates to improvements in automatically balanced cranes,
consists in the use therein of a travelling counterweight connected to the working
chain of the crane and operated so as to counteract any tendency on the part of
the crane to be overbalanced by the strain exerted at the front in raising or
lowering weights.
Extending backwards from the body of the crane frame are rails or bars which
serve as a track or way for the wheels of the travelling counterweight. The rails
are curved or inclined upwards as they extend backwards from the body of the
crane frame.
The working chain of the crane is connected at one end to the barrel of the
windlass as usual. Thence the chain is conducted over a pulley carried in bearings
towards the outer end of the jib and is passed below the pulley of the pulley block
to which is connected the hook by which the weights are attached. The chain is
then carried upwards and passed over a pulley carried in bearings at the top of
the jib, and, after having been conducted back over the jib, is attached to a
cross-shaped frame which is connected by chains or ropes to the travelling
counterweight.
To the rear end of the middle limb of the cross-shaped frame is attached a chain
which is passed over a series of pulleys situated over the upper end of the cylinder
of a hydraulic ram.
Thence the chain is conducted down and passed round a similar series of pulleys
carried at the lower end of the plunger of the ram, and is anchored beyond the
latter series of pulleys to any convenient fastening.
The water or other liquid for the rau is contained in a tank or resevoir
conveniently carried upon the frame of the crane.
Communication between the ram cylinder and the tank is controlled by a valve
operated through the medium of a spindle which is actuated as hereafter described.
At the lower end the valve spindle is furnished with an antifriction roller or disc.
The frame of the crane is hinged at the top to the king post and is capable of
being tilted on its hinge to an extent limited by the size of an orifice in the bed
plate. Upon the bed plate is a loose plate baving on its face a wedge.
This plate fits the king post and is stationary. The action of the crane in
operation is as follows:-
In its normal position the counter weight is at the "home" or inner end of
its travel; the valve of the rain is closed, the roller or disc at the lower end of
the spindle being at a point which ensures this. The weight to be raised being

page_text: attached to the hook, the windlass is put into operation, the frame of the crane is
tilted forward and the counterweight drawn back on the rails aforesaid. By the
tilting forward of the frame the valve of the ram, previously closed, is opened, the
disc or roller of the spindle being caused to ascend the wedge below it. When
the counterweight has travelled back on the ways to counterbalance the weight
brought to bear at the front, the frame is tilted backwards and the ram valve
closes. The liquid previously admitted to the cylinder is prevented from escape
and the ascent of the plunger is arrested. The effort exerted at the windlass is
then made available for raising the weight, and the strain taken by the crane is
received vertically on the king post.
Referring to the accompanying sheet of illustrative drawings, Fig. 1 thereon
represents a longitudinal section of a crane constructed and arranged in accordance
with this invention. Fig. 2 represents a plan the windlass being omitted.
Fig. 3 is a transverse vertical section taken through the centre of the ram
cylinder.
"
Extending backwards from the middle part of the frame A of the crane are bars
or rails A¹ which serve as a track or way for the wheels b of the counterweight B..
In the form shown in the drawing the counterweight consists of a box or chest
designed to be charged with lead or other suitable substance. Other forms of
counterweight may be used. The rails A¹ are curved upwards as they extend
backwards, the degree of curvature or inclination being such as to admit of proper
control by the ram of the travel of the counterweight.
The working chain C is attached at one end to the barrel e of the windlass E.
Thence the chain is conducted over the pulley g carried in bearings in the jib G,
and is passed under the pulley h of the pulley block H which carries the hook by
which the weights to be raised or lowered are attached. The chain C'is then
carried up and passed over the pulley g¹ at the top of the jib G, and, after having
been taken back over the jib, the chain is attached to the cross-shaped frame I
which is connected by the chains c to the counterweight B, as seen more
particularly at Fig. 1.
To the rear end of the short limb of the frame I is attached one end of the
chain C which is passed over a series of pulleys i situated over the cylinder K of
the ram.
Thence the chain C is conducted downwards, and, after having been
passed round a similar series of pulleys ; carried at the lower end of the ram
plunger J, is anchored at any convenient place.
The water or other liquid for the ram is contained in a tank or resevoir M which
communicates with the cylinder K by means of the pipe m, the communication
being governed by the valve n. The valve n is not attached to the spindle n¹.
At its lower end the spindle n¹ is furnished with an antifriction roller o free to
turn in its bearings. The valve n is guided in its vertical travel by the rod n'
attached to its upper face-see Fig. 3.
The frame of the crane is pivotted at a to the king post L and is capable of
being tilted on its pivot within the limits afforded by the space X in the bed
plate P. Upon the bed plate P is a loose plate Q, which fits round the king post
and revolves with the whole machine when necessary.
Upon the face of the plate Q is a wedge r.
At Figs. and 5 are shown
respectively a longitudinal section and plan-drawn to an enlarged scale of the
bed plate P and the loose plate Q.
In its normal position as shown in the drawing-the counterweight B is at the
" home or inner end of its range of travel, the valve n is down on its seat, the
roller or disc o at the lower end of the spindle n³ being at a point which ensures
this. The weight required to be raised being now attached to the hook, the
windlass E is put into operation, the crane frame is tilted forward by the jib G
and the counterweight B drawn back on the rails A¹. By the tilting forward of
the crane the roller o ascends the wedge, the valve n is opened and the plunger J
of the ram rises in the cylinder K and expels the liquid behind it into the tank M.

page_text: When the counterweight B has travelled back on the rails A¹ to the point
required to overbalance the weight brought to bear against it, the frame of the
crane is tilted back, the roller o of the spindle n¹ descends to the point of the
wedge and the valve n descends to its seat and closes the communication between
the cylinder K and the tank M. Further ascent of the plunger J is thus obstructed
and the effort exerted at the windlass E is then made available for raising the
weight connected to the working chain, and the strain is received vertically on the
king post.
Instead of the means described for operating the valve n, a lever may be
employed carrying a roller and hinged to an arm to be operated by the action of
the tilting frame of the crane.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what
I claim is:-
1st In a crane the use of a travelling counterbalance weight such as B, or its
equivalent, mounted on rails such as A' and actuated to counterbalance the crane
in an automatic manner through the medium of the hinged frame A, substantially
as herein before described and for the purpose specified.
2nd In a crane the use of a plate such as Q having a wedge such as r, or fitted
with mechanism equivalent thereto, for opening a valve such as n and permitting
the same to close, through the medium of the hinged frame A and counterbalance
weight B, substantially as described and for the purpose specified.
3rd The combination in a crane of a hydraulic ram and valve, a travelling
counterbalance weight such as B and chains or ropes C, C¹ and c and windlass E,
arranged and operating substantially as herein before described and shown in the
accompanying sheet of drawings.