US2500459A - Work supporting attachment for hoists - Google Patents

Description

March 14, 1950 w. s. HoovER ETAL 2,500,459

WORK SUPPORTING ATTACHMENT FOR HOISTS Filed May 24, 1948 I n n- Wf/ amg VL//f/fl Siwa/IMO@ i 717i!! iam 5. l'oo z/er' and Thamaslfjea www mentes Mu. 14, 195o :rows

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, ,Callf sspueeuen my :4, im. semi Na zam Chilli. 287-1) This invention relates to an auxiliary lowering attachment for hoists and has as its primary object the provision of a device for use in connection with a hoist, such as ablock and tackle, employed in the assemblage of heavy structures, in cases where it is necessary to bring a suspended part into accurate alignment or assemblage with a stationary part to which it is to be united, and whereby the suspended part may be lowered independent of the hoist from a position slightly above the position it is to occupy when assembled, and whereby proper positioning of the suspended piece may be more readily eifected than through Athe medium of the hoist alone.

Another object is to provide a lowering device by means of which a load may be lowered with extreme slowness whereby the load may be set down or positioned on a determined plane with a high degree of accuracy as in disposing a suspended heavy structure in apposition in which side openings or projections thereon are brought into register or alignment with side openings or projections on another structure. v

vAnother object is to provide an auxiliary lowering attachment for hoists which is hydraulically controlled and in which the lowering operation' is effected through the manipulation of -a' control valve to permit discharge of entrapped fluid beneath a load supporting piston to .allow the latter to move downwardly in accordance with the volume of the released iluid.

Another object is to provide a construction whereby the load carrying piston maybe auto'- matically restored to normal on being relieved of its load -but under the-control of a hydraulic control valve.

A further object is to provide an arrangement whereby a load carrying piston in moving under the iniiuence of the load imposedv thereon will move in opposition tb the resistance of hydraulic fluid passing through a restricted oriilce and also against the increasing resistance 4oi? a coiled" spring tensioned to oppose movement of the piston under its load.

With the foregoing objects in view, together with such other objects and advantages as may subsequently appear, the'invention resides in the parts and in the combination, construction and arrangement of parts hereinafter described and claimed, and illustrated by way of example in' the accompanying drawing, in which:

Fig. l is a view of the attachment as seen in vertical section with parts shown in elevation;

Fig. 2 is a detail horizontal section taken on the line2-2ofF1g.1: and

, 2 Flg.3isadiagraminsideelevationillusnating the application and mode of operation of the invention. Referring to.the drawings more specifically A lindicates an elongated tubular housing formed with an end wall I constituting a lower when v`the housing is disposed in an upright or. vertical' position. The interior of the housing A V is formed with a cylindrical interior which is' preferably lined with a replaceable cylinder I whicl'rsnugly fits the inner surface of the housing and extends'rrom the lower' end wall I to. the other or vupper end of the housing, which latter' is provided with a removable cap I closing the upper end of the cylinder I. The cap I is de tachab'ly secured tothe upper end of the housingAas by bolts 1. lThe cap I isiltte'd with'i.' yoke Ifor engagement with .the hook I of the conventional' block and tackle B as illustrated in 3, or other suitable hoist, whereby the. husin'gjl may be suspended in its vertical posi ion.;I

Arranged within the 'cyunde'i is a piston c fixed n: a stem II 'projecting through the lower end wall I of the housing and fitted on its. lower end with a swivel ,hookg il for engagement with piece l? to be and lowered in relationto" a nx plece E. A packing gland!! is carried?- by thu' end wall I and encompassesthezlte'lrllfy 'I l to iriford @seal therearound. A coiled spinarl'A between the piston C and wall Ijbf the housing and is tensioned tolyield# and also to restore the ptstoi to its'uppennsat position when freed of a load after depressed.

Formed in the iower'feu-pertion of inder I is ayport- Il which "opens toa ls in the' housing s leading to the' mtenervoff the eyunder above the piston c adjacent the *up-f per end of, the cylinder through a port II. The

cylinder e and the passage is is nneswitna ametrically through thestem adaptedtobe siiioned in and out oi' communication with the passage I5. The stem I1 is encompassed by a packing gland I9 and is tted with a handle 20 by which it may be turned to open or close the valve B.

A collar 2| is fixed on the stem i0 in suitable spaced relation to the wall l to serve as a Stop to limit downward movement of the piston; the collar being adapted to abut the end wall I when the stem I is advanced therethrough the determined distance.

In the application and operation of the invention the housing A is suspended from the hoist B with the piston C in its uppermost position in the cylinder and with the valve H closed. The piece D to be suspended is attached to the hook l i and the hoist B is operated to elevate the piece to a plane slightly above the position that the piece D is to occupy when assembled with its companion piece E as shown in full lines in Fig. 3. Having thus disposed the piece D proximate its assembled position the valve H is operated to partially open the passage l5 thereby permitting the ow of lluid G from beneath the piston C under the load imposed thereon, thus permitting the piston to move downwardly in opposition to the spring F. The piece D is thus lowered to the desired point whereupon the valve H is closed, thereby cutting oil the ow of the uid G from beneath the piston C and preventing further downward movement of the latter within the cylinder. The piece D will then be held suspended in its secondary lowered position, as illustrated by dotted lines in Fig. 3 with projections a on the piece D aligned with holes b in the piece E so that the projections may then be readily inserted in the holes. If perchance the piece D is thus lowered beyond the point of or below the plane of its assemblage with the piece E it may again be elevated by the hoist B and if need be the valve H again manipulated to effect the lowering of the piece to the required position.

During the downward movement of the piston C under the load of the piece D the spring F is placed under compression so as to resist downward movement of the piston and which resistance increases progressively as the piston moves downwardly. The spring F thus yieldably opposes downward movement of the piston C which with the control ail'orded by the valve H enables extremely delicate regulation of the lowering of the piece D relative to the hoist B.

While we have shown and described a specific embodiment of our invention we do not limit ourselves to the exact details of construction set forth, and the invention embraces such changes, modifications and equivalents of the parts and their formation 4and arrangement as come within the purview of the appended claims.

We claim:

1. In a supplemental lowering attachment for hoists, a housing, an enclosed cylinder within said housing, a piston in said cylinder. a stem attached to said piston having an end portion extending exteriorly o! said housing, a load engaging member on said stem, a hydraulic uid within said housing nlllng said cylinder on opposite sides of said piston, a passage connecting the opposed end portions of said cylinder, a regulating valve in said passage, and a coiled spring wound around said stem in said cylinder yieldably opposing movement of said piston in one direction under the urge of a load on said stem and operable to restore the piston from an advanced to a normal position when the stem is free oi.' a load and when the valve is open.

2. In a supplemental lowering attachment for hoists, a tubular housing, an end wall on said housing, a cylinder lining the interior of said housing having a port adjacent each of its ends, said housing being formed with a passage leading between said ports, a removable cap on said housing closing one end of said cylinder, a piston' within said cylinder, a stem extending through said end wall on which said piston is mounted, a coiled spring interposed between said piston and end wall yleldably opposing movement of said piston in one direction and operable to move the piston in the opposite direction, a hydraulic fluid occupying the space Within said cylinder on opposite sides of said piston and lling said ports and passage, and a control valve in said housing arranged to close said passage and cut oil flow of fluid therethrough and operable to open said passage to the oW of the uid therethrough.

3. The structure called for in claim 2 together with a collar on the stem cooperable with the end wall to limit movement of said stem in one direction.

4. In a supplemental lowering attachment for hoists, a cylinder, a piston therein, a stem carrying said piston, a housing encompassing said cylinder having an end wall through which said stem projects, said cylinder having a port adjacent each end thereof and said housing having a passage connecting said ports, a hydraulic uid filling said cylinder on opposite sides of said piston and occupying said ports and passage, a control valve for regulating the flow of uid through said passage and for preventing such flow, means for attaching said housing to a hoist in a suspended position, and means for suspending a load on said stem.

5. The structure called for in claim 4 togetherv with spring means for yleldably opposing advance movement of said stem in one direction under the inuence of a load imposed thereon and operable to move the stem in the other direction after having been advanced on being relieved of a load.

- WILLIAM S. HOOVER.

THOMAS H. REA.

No references cited.

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