US2726755A

US2726755A - Guarded winding drum

Info

Publication number: US2726755A
Application number: US393641A
Authority: US
Inventors: Irving S Moser
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1953-11-23
Filing date: 1953-11-23
Publication date: 1955-12-13
Anticipated expiration: 1972-12-13

Description

Dec. 13, 1955 s, MQSER 2,726,755

GUARDED WINDING DRUM Filed Nov; 23, 1953 To Load Man pulls this end INVENTOR. Irving 5. Maser,

A TOR/V5 Y- United States Patent O 2,726,755 GUARDED WINDING DRUM Irving S. Moser, Houston, Tex., assignor, by mesne assignments, to Esso Research and Engineering Company, Elizabeth, N. J., a corporation of Delaware Application November 23, 1953, Serial No. 393,641 3 Claims. (Cl. 203-340) This application is directed to a guarded hoisting drum.

The objects and advantages of the present invention may be seen from the following description taken with the drawing in which the single figure is in the form of an elevation with parts cut away and with portions shown schematically.

It is conventional in the art to use a hoisting drum with a load carrying line wrapped around the hoisting drum with one end of the line attached to the load and the other end held by an operator. The operator may tighten the wraps of line on the hoisting drum so that the load is lifted by frictional contact between the Wraps of the line and the rotating hoisting drum. The operator may disengage the load from the hoisting drum by slackening the line so that there is not suflicient frictional contact between the wraps of line and the drum to support the load.

The present invention is directed to a hoisting drum with which a load supporting line is used. In the device of the present invention, the wraps of line on the hoisting drum are totally enclosed so that only the ends of the line are exposed. In this way the hazard of an operator being caught in the wraps of line on the drum'is eliminated.

Turning now specifically to the drawing, a shaft A is adapted to be connected to and rotated by a suitable prime mover P, such as a steam engine or the like. In order to simplify the drawing, the prime mover has been shown schematically.

Mounted on shaft A are two coaxial cylindrical hoisting drums B and C. Drums B and C have their outside surfaces 7 and 8 respectively of identical diameter and have adjacent ends 9 and 10 substantially abutting each other so that they define a common cylindrical surface and yet allow the two drums to have rotational movement independent of each other.

Drum B is fixed to shaft A with its axis concentric therewith by cap screws 11 and 12.

Drum C is mounted for free rotation with respect to shaft A and drum B. In the drawing, this free rotation is provided by bearing

assemblies

13 and 14 which are arranged to carry drum C on shaft A. It will be seen that with this arrangement drum C is arranged for free rotation or may be described as a free wheeling drum with respect to drum B and shaft A.

A load carrying line D is shown with a portion thereof wrapped on the common cylindrical surface provided by drums B and C with the wraps designated as 15, 16, 17, 13, and 19 and the two ends designated as 20 and 21.

A cover E is made up as a unit which consists of a cylindrical portion 22 terminating in inwardly extending annulus shaped

ends

23 and 24. Adjacent end 23 is an opening 25 through which end 20 of line D extends and adjacent end 24 is an opening 26 through which end 21 of line D passes. The annular space bounded by the inner surface of cylindrical section 22, the inner walls of

ends

23 and 24 and the common cylindrical surface of drums B and C embraces the wraps of line through 19, inclusive, of line D. While this space provides ample clearance for the free operation of line D, its limits are such that addi- 2 tional wraps of line cannot be put on the common cylindrical surface defined by drums B and C. This insures that a fixed number of wraps of line remain in the desired relationship at all times.

A power means F is arranged for moving cover E along the longitudinal axis of shaft A and drums B and C. This power means is shown diagrammatically as a rectangle 27 which may represent, for example, a piston and cylinder assembly powered by compressed air, this assembly being connected through rod 28 to cover E. Means for actuating the power means is designated as G.

consists of a compressed air supply line 29 connected to a suitable supply of compressed air, not shown in the drawing, and connected to valve 30 which in turn is connected through compressed air line 31 to the power means 27. The valve means 30 may be actuated by a treadle 32, the end of which may be engaged with the teeth of lever 33 pivoted at point 34. The treadle 32 may be released as desired by the use of foot operated lever 35 which is pivoted at point 36.

In the device shown, the maximum number of wraps of load carrying line which are intended to be used with the device are wrapped on the common cylindrical surface defined by surfaces 7 and 8 of hoisting drums B and C. If the drum cover E is moved to its extreme right position, all of the wraps of line are on the surface 8 of free wheeling drum C and no load can be picked up by the drum shaft A. To carry a load, the cover E is moved from its extreme right position to the left so as to cause the desired number of wraps of line to be brought into contact with surface 7 of drum B for carrying the load when the line D is frictionally engaged therewith. For convenience it will be assumed that end 21 is fastened to the load while end 20 is handled by the operator and to lift the load the operator pulls on end 20 with enough force toproduce the required frictional contact between drum B and load carrying line D.

The wraps of line 15 to 19 are contained in cage E and these wraps are moved longitudinally by moving cage E. In the embodiment shown, this movement is actuated by prime mover F which in turn is controlled by the operators actuation of treadle 32 and lever 35.

The preferred method for using the device of the present invention is for the operator to move cage E to the extreme right position when carrying no load. Then to pick up a load, the operator depresses treadle 31 which forces the cage E to move to the left, the operator moving cage E to the left such an amount as to slide the desired number of turns of line from free wheeling drum C to load carrying drum B.

It is Well known that the advantage of a hoisting drum may be designated by the formula:

Tz=pull of operator =coefficient of friction 0=radians of contact of rope on cathead Thus, the operator will cause cage E to place such a number of turns on the load carrying drum B as is necessary and still allow the operator to have a good feel on the line. Thus, although the number of turns carried in cage E is the number required to lift the maximum load to be handled by the device any time, the operator can select the number of turns which will actually carry the load and still allow him to have a good feel on the line since the turns which remain on the free wheeling spool C do not take up any load.

The assembly G While a'specific embodiment of the present invention has been described, it will be obvious to a workman skilled I mounted on a rotatingtshaft comprising, in combination,

a first drum having a cylindrical surface arranged to be concentrically fixed to said shaft for rotation therewith, a second drum having a cylindrical surface of the same diameter as said first drum, bearing means carried by said second drum for mounting it on said shaft concentric with said shaft and with said first drum for rotative movement with respect to said first drum and shaft with an end of said first drum and an end of said second drum substantially abutting so that the outer surfaces of said first and second drums define receiving wraps of line, a'cover slidably mounted on the cylindrical surfaces of said first and second drums and cooperatingrtherewithto form an annular shaped space of fixeddimensions movable longitudinally along the common axis of said drums and receiving a single layer of a predetermined number of wraps of a load carrying'line with the ends of the line freely slidable, and means connected to said cover arranged to move said cover along the longitudinal axis of said drums.

2. A guarded hoisting drum assembly adapted to be mounted on a rotating shaft comprising, in combination, a first drum having a cylindrical surface arranged to be concentrically fixed to said shaft for rotation therewith, a second drum having a cylindrical surface of'the same diameter as said first drum, bearing means carried by said second drum for mounting it concentrically on said shaft for free rotative movement with respect to saidfirst drum and said shaft with an end of said first drum and an end of said second drum substantially abutting so that the outer surfaces of said first and second drums define a common cylindrical surface for receiving wraps of a single layer of line, a generally cylindrical cover having inwardly a common cylindrical surface for wraps on said common cylindrical surface, a cover having ,Which a line may pass,

cover being radially spaced away from the surfaces of extending end' flanges mounted onrsaid first and second drums with said end flanges making sliding contact with the cylindrical surfaces of said drum with an opening at each end of said cover adjacent said end flanges through. the cylindrical portion of said said drums to receive a'. single layer of a predetermined number of wraps of a load carrying line, and means connected to said cover arranged to move said cover along the longitudinal axis of said shaft. 7 a

3. A guarded hoisting drum comprising, in combination, a drum shaft, a first cylindrical drum concentrically fixed tov said shaft for rotation therewith, a second drum having the same diameteras said first drum, bearings arranged to mount'said second drum on said shaft with adjacent ends of said first and second drums substantially abutting so that the surfaces of said first and second drums define a common cylindrical surface for receiving a single layer of wrap of a load carrying line with said second drum freely rotative with respect to said shaft and said first drum, a load carrying line having a single layer of a cylindrical body and inwardly extending end flanges with a first opening at one end and a second opening at the other end through which a line may pass mounted, over the wraps of said line with a first end of the line extending through the first opening and a second end of the line extending through said second opening, the inner surface of said cover cooperating with the common cylindrical surface of said first and second drums to define an annulus for receiving a single layer of a predetermined number of wraps of said line, and means arranged to move said cover along the longitudinal axis of said shaft and drums.

References Cited in the file of this patent UNITED STATES PATENTS Segelhorst Apr. 8, 1924 Kelley Sept. 12, 1950