US2242393A - Cable hoist - Google Patents

Description

y 0 1941- r H. A. HARRISON. 2,242,393

CABLE HOI S T Filed 001:. 4, 1937 2 Sheets-Sheet 1 INVENTOR, jaam 542 2222072 Patented May 20, 1941 UNITED STATES-PATENT OFFICE CABLE HOIST Hugh Adam Harrison, Dallas, Tex., assignor of one-halfto Hugh Roy Harrison, Dallas, Tex.

Application October 4, 1937, Serial No. 167,120 1 Claim. (Cl. 254-177) One object of the invention is to provide a hoist of economical and desirable construction, which may be readily and conveniently utilized for raising or lowering a scaffold or the like to any desirable height or distance with a minimum loss of time and expense in use.

Another object of the invention is to provide new and novel means of connection between the scaffold and the suspension cable, whereby the scaffold will travel up or down the cable intermediate its ends.

A further object of the invention is to provide a new and novel means of suspending a scaffold from cable whereby a single cable of unrestricted length may be used for the suspension of numerous scaffold units, thereby eliminating the need for a number of various length cables on construction, repair or maintenance jobs of different sizes.

A construction designed to carry out the invention will be hereinafter described together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings in which an example of the invention is shown, and wherein:

Figure 1 is a side elevation of a device constructed in accordance with the invention.

Figure 2 is an end view of the same.

Figures 3 and 4 are vertical sectional views of the cable hoist taken at right angles to each other.

Figure 5 is an end elevation of a modified form of the invention for use when it is desired to suspend each corner or opposite sides of the scaffold.

Fig. 6 is a broken sectional view through one of the drums of the cable hoist.

In the drawings, as best shown in Figures 1 and. 2, the letter A designates the platform or main bed of a scaffold, which platform is formed of transverse supporting angles I upon which are mounted a plurality of planks or boards I I.

Angle bars l2 and I3 welded together in an angle shaped bracket are pivotally suspended from corresponding ends of each of the transverse angle bars ID by means of bolts l4 connecting the upper end of the angles l2 and the ends of the transverse angles 10. Angle braces l are pivotally connected between the lower portions of the angle bracket and said transverse angles l0 by bolts I6 for rigidly bracing the brackets, whereby planks I1 extending between said brackets form a suspended portion or drop walk B. By removing one of the bolts IE to disconnect the brace the drop walk may be pivotally retracted beneath the platform A for clearance of cornices l8 or other similar projections from building [9 (shown in dotted line) upon which the scafiold is being used in construction or repair work.

As best shown in Figure 1 the planks II are usually connected by cross ties 20 positioned at opposite sides of the transverse angles It] to prevent accidental displacement as well as increase stability. The planks H are likewise secured by cross ties 2!.

In Figures 1 and 2 the scaffold is shown suspended by means of a single cable 22 at each end of the scaffold, which cables are suspended from overhanging or projecting beams 23, usually located at the top of the building, as indicated in Figure 5. Each of the cables is wound or looped around a pair of drums 24 and 25 of a cable hoist C, with the lower end of the cable hanging loosely through a slot or crack in the platform A.

As best shown in Figures 3 and 4, the cable hoist 0 comprises a frame consisting of vertical channels 26 spaced apart at their upper ends by bars 2'! and at their lower ends by a U shaped member 28. This U member 28 is pivotally suspended from the channels 26 by a transverse bolt 29 and is rotatably connected with the transverse angle IU of the platform A by a suspension bolt 30, thus providing a semi flexible connection between the hoist and the platform.

The drums 24 and 25 are rotatably mounted in vertical alignment at the lower portion of the frame on shafts 3| and 32 which have their opposite ends extending through bossed portions 33 of the channels.

The drum 24 is loosely mounted on the shaft 3| which is secured in the frame by cotter keys 34. This drum has a smooth face and circumferential flanges 35'at its end to prevent-displacement of the cable.

The drum 25 is preferably provided with a plurality of separate annular grooves 36, best shown in Figures 3, 4 and 6, with which the cable 22 is engaged when looped around the drums 24 and 25 jointly As shown in Figure 6, these grooves are preferably wedge or V shaped to provide a maximum frictional contact or grip between the cable and the drum. This drum 25 is keyed to the shaft 32 which has one end 31 squared for receiving a ratchet wrench 38 or the like for turning the drum 25 to raise or lower the scaffold. Mounted on the shaft 32 adjacent the drum 25 and likewise keyed thereto is a ratchet wheel 39,

which is adapted for engagement by a pawl 40 that is loosely mounted on the shaft 3|. This pawl is held in engagement with the ratchet by gravitational force and by the added weight of a projecting operating handle 4|.

It is pointed out that, the wedge or V shaped grooves of the drum 25 provide greater frictional resistance between the cable and the drum than would be had if the drum were smooth. However, the invention is not to be limited to the use of grooved drums as good and advantageous resul are had with smooth faced drums. I

In mounting the hoist on the cable, the cable 22 is passed through a guide 42 on the cross-brace 21 and then looped under the bottom drum 25 and over the top drum 24 for 3 or 4 turns. The lower end of the cable is then left hanging through the scaffold and is preferably held taut by an 8 or'lO pound weight attached to its lower end. The

weight of the empty scaffold alone acting on the cable around the drums sets up more than sufficient frictional contact between the cable and the drums to securely hold the scaffold in position dependent on the rotation of the lower drums 25 for either upward or downward movement. The greater the weight of the scaffold the tighter the cable will grip the drums and the more secure the position of the scaffold against accidental displacement.

For stabilizing the scafiold A, a tie rod 43 connects the hoist with one side of the scaflold, preferably the front side or that on which the drop walk is located. This rod is secured by screw threaded nuts 44 to the web of one of the vertical channels 26 of the hoist C and has its lower end adjustably secured by screw threaded nuts 45 to an angle clip 46 which is welded to a corner upright 41 at the forward side of the scaffold. This rod not only serves as a brace but also as a levelling device by adjusting the nuts 45 on the rod the angle of tilt between the hoist and the scafiold may be varied to level the platform A as desired.

In Figure 5, I have shown an alternate form of the invention in which a cable hoist is used at each corner or opposite side of a scaffold for carrying greater loads and providing increased stability. These hoists D are substantially the same construction as the hoists C and each comprises a pair of vertical channel members 48 and 49 welded in spaced relation at their lower ends to the end portion; of a transverse angle 50 and secured at their upper ends by cross brace 5 I welded therebetween. In this form the frame is a rigid element of the scafiold in lieu of the loosely mounted frame of the hoist 0, previously described.

Cable drums 24' and 25' are mounted between the channels 48 and 49 similar to that of the drums 24 and 25 and are provided with a ratchet 39 and pawl 40'-4i' similar to those hereinbefore described. In mounting the hoist for use, the cable 22 is passed through a guide 42 on the cross brace 5| and looped around the drums as previously described.

The remaining construction of the scaffold shown with this alternate form of hoist is similar to that of the scaffold previously described and corresponding parts are identified by corre sponding numerals followed by a prime symbol such as l2, l1, etc., duplicate description being unnecessary. v It is pointed out that either form of hoist described herein or its equivalent may be used with "scaffolds or platforms other than those described and shown, and likewise that the scaffold or platform described herein may be used with other types of hoists or hangers, therefore the invention is not to be restricted to the combined use of the hoist and the scaffold described herein other than is required for securing the advantages and utility eifected only through their combination.

lit is pointed out that with this arrangement the drums literally climb or descend the cable, without accumulating coils of cable on the drum and obviously restricting the movement of the scaffold to limited capacity of the drums and decrease of actuating leverage through increased diameterof cable roll on said drum, as is the condition encountered with the use of hoist on which the cable is wound continuously.

Furthermore, with this invention the cable may be used in indefinite lengths such as on a jdb employing a continuous or adjacent scaifold supported by a quantity of hoists, a single cable pended claim.

What I claim is:

A cable hoist having a frame, a pair of spaced shafts mounted in said frame, one of said shafts being rotatable and the other fixed, a lower drum axially fixed to said rotatable shaft and an upper drum axially rotatable on said fixed shaft, a suspended cable having a plurality of loops wound around said drums, said cable depending from above said hoist about said lower drum,'then' upwardly over said upper drum, and so for a number of turns and finally extending downwardly from said upper drum, a ratchet wheel and operating handle fixed to said rotatable shaft and a pawl loosely mounted on said fixed shaft cooperating with said wheel.

HUGH ADAM HARRISON.

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