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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C23/00—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes
- B66C23/62—Constructional features or details
- B66C23/72—Counterweights or supports for balancing lifting couples
- B66C23/74—Counterweights or supports for balancing lifting couples separate from jib
- B66C23/76—Counterweights or supports for balancing lifting couples separate from jib and movable to take account of variations of load or of variations of length of jib
UNITED STATES PATENT OFFICEo THOMAS WRIGHTSON, OF TEESDALE IRON WORKS, ENGLAND.
SPECIFICATION forming part of Letters Patent No. 234,160, dated November 9, 1880.
Application filed September 27, 1880.
To all whom it may concern:
Be it known that I, THOMAS WRIGH'rsoN, a subject of the Queen of Great Britain, residing at the Teesdale Iron Works, near Stockton-on-Tees, in the county of Durham, England, have invented certain new and useful Improvements in Center-Cranes and in other mechanism in which in like manner a jib or beam is supported by and movable with or about a central standard, (for which I have received Letters Patent in England, No. 2,749, dated July 5, 1880,) of which the following is a specification.
This invention has for its object improvements in center-cranes and in other mechanism in Which in like manner a jib or beam is supported by and movable with or about a central standard.
In center-cranes as at present constructed it is usual to have a horizontal `jib or beam carried upon the head of the ram of a hydraulic press. The load, consisting, say, of the ladle containing the metal, is applied at the outer end of the jib or beam, and by the injection of water to the cylinder of the press the ram, the jib or beam, and the load are all raised together vertically, and the load can be carried around a circular course either by the rotation of the ram Within the press-cylinder or by the movement of the jib or beam upon the top of the ram. At present the dimensions to which these cranes can be made are limited by the very heavy strain which is experienced when a heavy load is held suspended at the end of a long jib or arm.
According to my invention I relieve the central standard from this strain. For this purpose I arrange the jib or beam so that it may rock through a small angle. Near the two ends of the jib or beam I attach to it stay ropes or chains, which Ilead round over headpulleys suitably carried above the standard, and I bring these ropes or chains together and connect them with a counterpoise. By this arrangement it results that while the jib or beam is, as usual, under the control of the central press and can be raised and lowered by it, and while the jib or beam is free to turn under the control of the center standard, nevertheless this standard is relieved (either in part or completely) from the tipping strain (No model.) Patented in England July 5, 1880.
by means of the stay ropes or chains, the overhead-pulleys, and the counterpoise. The jib or beam by tipping tightens the stay ropes or chains attached to its more heavily loaded end, While the stays upon the other side become comparatively slack.
A very convenient arrangement for a cenF ter-crane is to have a center post supported at the bottom so that it may be able to turn freely. The post also has a top bearing. It may be in the roof of the building. rI he lower part of the post is surrounded by a cylinder having glands at its ends, so that it can work up and down water-tight upon the post. The part of the post which works in the lower gland is larger than the part which works in the upper gland, so that when water under heavy pressure is admitted to the cylinder it rises up upon the post. The water is admitted by a hydraulic pivot to the lower end of the post, and it issues by an aperture in the side ofthe post and is conveyed from it to the cyl inder. At the top of the post there is a frame of pulleys receiving the stay ropes or chains. The cylinder carries the jib or beam, which, however, is not fixed to it, but is connected in such a manner that it is free to rock through a small angle. The counterpoise is of an annular form and surrounds the post. I make the counterpoise of about one-half the weight of the load-it may be more or less-and I also put a weight-say one-half that of the load-at the opposite end of the jib or beam. In cases where it is inconvenient to employ a suspended counter-weight a small hydraulic press may be substituted.
In order that my invention may be fully understood, l have shown in the drawings hereunto annexed a crane in which my improvements are embodied.
Figure l shows a side elevation, partly in section, of the crane. Fig. 2 shows a horizontal section of the same, and Fig. 3 an end elevation, partly in section.
A is the central post, which, in order that it may revolve freely, I support in a water-pivot. Surrounding part of this post is a cylinder, B, which, by means of a key, is caused to turn with the post. C is a support, attached, say,
to a roof, for supporting the top of the post. The cylinder is, as shown, provided at the bot- IOO tom with a gland of larger diameter than at the top, so that by admitting water under pressure to the cylinder the cylinder can be caused to rise upward on the post.
D is an arm orjib extending on two opposite sides of the post A.
E E are pivots at the bottom of thc cylinder, on which the arm or jib l) can have a slight rocking motion.
F is a frame tixed on the central post and carrying sheaves F.
G is an annular balance-weight surrounding the post, and connected by chains, which pass over the shea-ves, to the two arms ot' the jib D.
H is a ladle on one arm of the jib, and capable of containing, when full,eight tons of steel.
I isa balanceweight on the opposite arm of the jih, adjusted so as to balance the cradle when the ladle contains half its charge, or tour tous ot' steel.
Tile annular balance-weight G, l make pret'- erably of such weightas will balance the whole four tous maximum prqionderating weight at any time possible ou the cradle, or it might he of greater weight.
J showsthelowest position otbalauce-weight when cradle is raised.
K is the water-pivot supporting the bottom ot' the post A. The area of the ram of this pivot is arranged so that nearly the whole constant weight is balanced by the pressure ot' Water admitted into the cylinder ot' the pivot to act upon the rain, the small remainder of the Weight coming on a steel center.
L are radial pipes conveying water to and from machinery on the jib-arm; M, position 0f the same pipes when cradle is raised.
N is a cylinder for moving;` ladle to and fro along the arm; 0, position ol' valves for controlling the working of the crane, at which point is also a platform, on which a man may stand to work the valves.
I is a water-passage from lower end ot' post A, by which water under pressure can pass to the radial pipes L L, and from them, hy a pipe, Q, to the valves at O.
R is a pipe for admitting water under pressure to and for exhaust from the lifting-cylinder.
S is a pipe for admitting water under pressure t0 and for exhaust from the back end of the cylinder by which the ladle is moved outing to radial exhaust-pipes V, which conduct the exhaust to an exhaust-passage in the post A, from which it passes out at the top through 6o a revolvingjoint at W.
The crane may be revolved by hydraulic or other machinery, or by hand, as desired.
I would state that, I do not conne myself to the means above described for controlling the movements of the cranes, as the valves for admitting water under pressure to and for exhaust from the lifting-cylinder might be at any spot outside the crane andthe water-passage from the valves to the lifting-cylinder be carried up through the center of the post or standard. When this arrangement for working the lifting-valves is adopted the valves for controlling the movement of the ladle outward or inward along,r the arm may be controlled in any suitable manner.
l would state that, in place of water-power being used to raise and lowerthejib-arm on the post and to move the ladle inward or outward along the jib-arm, other mechanical means might be used to effect these objects.
Having thus described my invention and the manner of performing the same, I would state that I claim- 1. The center-crane or other mechanism in which a jib or beam is supported by and movable with or about a central standard., with the jib or beam projecting on two opposite sides of the central standard and capable of rocking upon pivots at the standard, and connected on both sides ot' the standard by chains passinar over pulleys ou the standard to a balanceweight which can rise or fall, or to a hydraulic press or equivalent therefor, substantially as described.
2. The center crane constructed with the jib-arm projecting on two opposite sides of the central standard and capable of rocking upon horizontal pivots at the standard, and with a means of carrying the load to he moved on one arm and a couuterbalanceweight of about one-half the load to be moved on the other arm, and with the two ends of the arm connected hy cords or chains passing over pulleys on the standard to acounterbalance-weight which can rise or fall, or equivalent therefor, substantially as described.
Geo. W. WILSON,
Stockton-on-Tees. ROBERT HowE,
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