US796807A - Scaffold-support. - Google Patents

Description

No. 796,807. PATENTED AUG. 8, l905.

Y M. GAVANAGH.

SCAPFOLD SUPPORT.

APPLIoATIoN HLBD Nov. 22.1904.

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PATENTED AUG. 8, 1905.

M. CAVANAGH. SCA-IFOLD SUPPORT.

APPLICATION FILED Nov. 22, 1904.

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MICHAELl CAVANAGH, OF NEW YORK, N. Y.

SCAFFOLD-SUPPORT.

Specicaton of Letters Patent.

Patented Aug. 8, 1905.

Application filed November 22, 1904` Serial No. 233,811.

. ments in the scaffold-support for which Letters Patent were granted to William J. Murray on September 6, 1904, No. 769,395, said improvements being designed with a view of remedying some of the defects of the scaffoldsupport referred to and to permit the quicker and more effective operation of the same when raising or lowering the scaold; and for this purpose the invention consists in the novel features and combinations of parts, which will be fully described hereinafter and finally pointed out in the claim.

In the accompanying drawings, Figure l is a front view of a part of the wall of a building, showing my improved scaffold-support suspended from the steel or iron frame of the building. Fig. 2 is a vertical transverse section on line 2 2, Fig. l. Fig. 3 is a side view of oneof my improved scaffold-supports. Fig. 4 is a plan view of Fig. 3; and Fig. 5 is a vertical transverse section of said scaffold-support on line 5 5. Fig. 3.

Similar letters of reference indicate corresponding parts.

Referring to the drawings, c designates a portion of a Wall of a building, which wall is built around and incloses the usual steel or iron framework composed of horizontallyarranged beams b and vertical columns or supports The framework of the building is also provided with horizontally arranged beams b2, which are placed at right angles to the front beams b, as shown in Fig. 2. As the Wallis raised and the erection of the building progresses, it is necessary to supply the material for the surrounding and partition walls, for which purpose it is customary to provide al scaffold c, which has to be raised as the wall is raised and the erection of the building gradually continued. The scaffold c is supported at either end by means of ropes f g, which are attached attheir lower ends by means of eyes to hooks on the scaffold and which are wound up on two parallel drums f g', that are supported on a horizontal frame which comprises two parallel beams CZ, that are placed transversely to the wall beam or beams b and extend suliiciently forward from the same so as to permit the free raising and lowering of the scaffold c, suspended from the ropes. The inner ends of the beams dl are attached to the supplemental transverse beams Z2 of the framework of the building by means of locking-yokes or other locking devices 0l', so as to be firmly held in position thereon. The beams d are preferably arranged in pairs, as shown in Figs. 1 and 4, and serve for supporting the framework e, on whichthe journal-bearings of the parallel drums f g are supported. The frame is made in the form of parallel side angle-irons e2 and transverse connecting members e3, said angle-irons resting on the beams Z of the framework and being attached thereto in any suitable manner, so as to prevent their shifting on the supporting-beams. To the angular side rails of the frame Je are attached the journal-bearings for the shafts of the drums f g', which drums are provided at one end with worm-gears f2 g2, which mesh, respectively, with right and left hand worms f 3 g3 of a worm-shaft s, which is supported in bearings at the upper ends of upright supports e', as shown clearly in Figs. 3 and 4. An actuating device for said wormshaft is operative from the scaffold to turn the shaft in either direction for raising or lowering the scaffold. The actuating device shown for this purpose will now be described. To the end of the worm-shaft s is attached a sprocket-wheel t, over which is passed an endless sprocket-chain L, which is of sufficient length to extend in downward direction nearly to the scaffold c. Separate locks are provided for each drum to render the scaold safe in case the thread of either worm should become worn or for any reason be disengaged from its worm-gear. This is important, because the disengagement of the worm-gearing for either drum would precipitate the occupant of the scaffold to earth. For convenience in operation-and to avoid a multiplicity of parts a releasing device common to both said locks' is operative from the scaffold. By such means the operator on the scaffold may release both locks with one hand and raise or lower the scaffold with the other. The opposite ends of the drums f g are provided with ratchetwheels t', the teeth of which extend in opposite directions and which are engaged by pawls z', that are pivoted to upright supports on the framework e, said pawls being provided with downwardly-extending arms 2, which are connected at their lower ends by ropes or other flexible connections 3 with the connecting ringer link c of a rope or similar connection i, that extends in downward direction to the scaffold, so as to be conveniently taken hold of by the man on the scaffold whenever it is desired to release the pawls or drop the same for locking the drums.

By operating the sprocket-wheel chain the worm-shaft is turned and the drums rotated in opposite direction to each other by the worm-gear transmission. The suspensionropes f and g on which the scaffold is suspended are wound upon the drums in opposite directions, one rope, f, being attached to one end of the drum, while the rope g is attached to the opposite end of the drum, so that the strain exerted by the suspensionropes on the drums, being in opposite direction, balance each other and produce thereby the even winding of the ropes on the drums, the ropes extending in downward direction at the outer circumference of the drums, Iso as to provide the distance required by them for suspending the scaffold without the necessity of any guide-pulleys for one or both suspension-ropes.

The scaffold can be raised and instantly stopped at any desired point owing to the wellknown locking action on the motion-transmitting worm-gears. While the scaffold is raised by the worm-gear mechanism described the drums are turned toward each othe r, while the pawls pass over the teeth of the ratchetwheel and are always held in locking engagement with the same, so that no danger of any slipping of the suspension-ropes under the weight placed on the scaffold is possible, the ratchet-wheel and pawl mechanism serving as an auxiliary safety-guard for the locking action of the worm-gear transmission. When the scaffold. is to be lowered, the pawls have to be released from the teeth, so as to permit the downward motion. For this purpose the ropet'5 is pulled, which lifts the pawls and withdraws them from the teeth of the ratchetwheels. The pawls are held out of engagement with the ratchet-Wheels by the rope until the lowering motion is completed, when they are permitted to drop again into engagement with the teeth of the ratchet-wheels. The scaffold-support is moved to the points required on the steel or iron framework of the building to be erected and also for the higher stories of the building as the erection of the same progresses.

The advantages of my improved scaffold-support are, first. that the construction is considerably sim pliiied; second', that the speed at which the scaffold can be raised or lowered is considerably increased; third, that the perfect safety and reliability of the scaffold is obtained owing to the combined action of the worm-gear and pawl-and-ratchet mechanism; fourth, that the suspension-ropes being arranged at the outside of the drums and wound up in diagonally opposite directions on the same prevent any uneven strain on the drums and produce the even winding on and unwinding of the suspension-ropes from the drums.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- A scaold -support comprising a frame, winding-drums supported thereby parallel to each other, suspension-ropes wound and unwound from said drums and adapted for connection with opposite ends of the scaffold,

worm-gears in fixed relation to said drums, a worm-shaft supported on said frame and provided with worms engaging said worm-gears respectively,means operative from the scaffold to turn said shaft in either direction for raising or lowering said scaffold, separate auxiliary safety-locks for the respective drums, and a releasing device common to said locks and operative from the scaffold.

In testimony that I claim the foregoing as my invention I have signed my name in presence of two subscribing witnesses.

MICHAEL CAVANAGH.

Vitnesses:

PAUL GonPnL, HENRY J. SUHRBIER.

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