US3298462A

US3298462A - Traction lift for scaffolding towers

Info

Publication number: US3298462A
Application number: US521134A
Authority: US
Inventors: Ronald G Morris
Original assignee: BEAVER ADVANCE CORP
Current assignee: BEAVER ADVANCE CORP
Priority date: 1966-01-17
Filing date: 1966-01-17
Publication date: 1967-01-17
Anticipated expiration: 1984-01-17

Description

Jan. 17, 1967 R o s 3,298,462

TRACTION LIFT FOR SCAFFOLDING TOWERS Filed Jan. 17, 1966 4 Sheet-Sheet 1 I. m 1\ I Ill INVENTOR. Ronald 6. Morris HIS A T TORNE Y5 Jan. 17, 1967 R. cs. MORRIS TRACTION LIFT FOR SCAFFOLDING TOWERS 4 Sheets-Sheet 2 Filed Jan. 17, 1966 INVENTOR. l5 Ronald 6. Morris 4m, firm/443 M Ill 1' H/5 ATTORNEYS Jan. 17,- 1967 R. s MORRIS TRACTION LIFT FOR SCAFFOLDING POWERS 4 Sheets-Sheet 3 Filed Jan. 17. 1966 INVENTOR. Ronald 6. Morris HIS ATTORNEYS Jafi. 17, 1967 R G. MORRE; 3,298,462

TRACTION LIFT FOR SCAFFOLDING TOWERS Filed Jan. 17, 1966 4 Sheets-Sheet 4 INVENTOR. Ronald 6. Morris ztw, fiZM HIS A T TORNE Y5 United States Patent O 3,298,462 TRACTION LIFT FOR SCAFFOLDING TOWERS Ronald G. Morris, Beaver Falls, Pa.-, assignor to' Beaver- Advance Corporation, Ellwood City, Pa., a' corporation of Pennsylvania 1 Filed Jan. 17, 1966, Ser. No. 521,134

14 Claims. cl. tsp-.2

This invention relates to "means or apparatus for raising and lowering an overheadtraction machine" and its supporting platform to, in stages, extend the height of operation of a personnel elevator duringfthe progress of building construction, and particularly to supplemental means associated with the traction machine for changing its operating height in accordance with the height to which personnel and equipment are to be lifted within a scaffold elevator tower.

I In building construction and maintenancework, it has been customary to employ tubular and other types of scaffolding members and sections for progressively building up the working levels. as the work progresses. Scaffolding for use on the outside of a proposed building construction will be constructed in stages, for example, from an initial height of about 60 or 70 feet up to about 150 feet representing severalstories, in successive stages to the ultimate height of the building which may be 400 to 500 feet. That is, the' building is constructed by the workmen up to the initial or first stage height of the scaffolding and then additional stages of scaffolding are built up for each additional height as it is completed and the procedure is continued until the'full height of the building has been attained.

The present invention deals with apparatus for use with a scaffolding tower in which a lift platform carrying the traction machinery or a machine unit for raising and lowering theelevator that is employed to'raise and lower the workmen and their equipment, is first fixed or secured at one height level or stage with respect to a personnel scaffolding tower, is then after work has progressed, raised to an upper level and fixed or secured in position thereat. The traction machinery is used at each such level until the need arises forfurther raising the overhead operating level. Heretofore difficulty has been encountered in raising and lowering the platform and the traction machinery from one stage orlevel to another, inthe sense of leap frogging, during the con struction of the building. It has heretofore been customary to use a'special overhead crane for accomplishing this. purpose. The use of such crane which is generally otherwise idle during the building work, greatly adds to the cost involved and takes up space that could otherwise be made available for more productive purposes.

It has thus been an object of my invention to solve the problem of raising or better, inexpensively and expeditiously changing the position of the traction machine and its platform in accordance with the progress of building construction work;

Another object has been to devise a means or approach to the problem which will make use of equipment associated with the traction or elevator raising. mechanism in order to eliminate the need for an independent means for the purpose of raising and lowering the traction platform;

A further object of my invention has been to make use of the traction machinery on the platform for, itself, raising the platform and such machinery from one stage of the building construction level to another;

A still further object of my invention has been to provide a practical and inexpensive approach .to ac commodating the height positioning of traction machinery to the progress of building construction work;

These and other objects of my invention will appear to those skilled in the art from the illustrated embodiment, the descriptionthereof and the claims.

In the drawings, FIGURE 1 is a top plan view of a traction machine, apparatus or operating unit constructed in accordance with my invention;

FIGURE 2 is an end view in elevation on the scale of and taken from the left end of the apparatus of FIGURE v1; 1 p FIGURE 3 is a side view in elevation on the scale 'of FIGURES land 2 and taken from the front side of the apparatus of FIGURE 1;

FIGURE'4is an enlarged side sectional view in elevation taken along the line IVIV of FIGURE 1;

FIGURE 5 is an end sectional elevation ,on the scale of FIGURE 4 and taken along the line V-V of FIGURE 1; I

FIGURE v6 is a. further enlarged perspective view of a winding drum constructedin accordance. with my invention in an exploded relation to illustrate details of its construction;

FIGURE 7 is a fragmental end section on the scale of FIGURE 6 and taken along the line VIIVII of FIGURE 2.; a

FIGURE 8 is an end section on the scale of FIG- URES 6 and 7 taken along the line VIIIVIII of FIGURE 2 I FIGURE'9 is a somewhat diagrammatic, greatly reduced, view in elevation illustrating a scaffolding tower and the stages in which it is built up and its traction platform is advanced during work progress in a building construction; I

FIGURE 10 isa fragmental side view in elevation on the scale of FIGURES 4 an-d 5, illustrating details of the construction and mounting of an overhead cathead shown in FIGURE 9;

FIGURE 11 is a fragmental top plan view on the scale of and further illustrating the cathead of FIG U FIGURE 12 is a side fragment in elevation on the scale of FIGURES 10 and 1 1 and illustrating details of a preferred construction and mounting of a traction or lift platform for use with the scaffolding tower of FIGURE 9;

FIGURE 13 is a top plan fragment on the scale of i and of the platform of FIGURE 12; and

FIGURE 14 is a greatly redueed top plan view showing the complete platform whose details are illustrated in FIGURES 12 and 13. 1 e

In carrying out my invention as particularly illustrated in FIGURE 9, where a scaffold tower 10 is shown positioned on ground level 9, an overhead, traction unit supporting or lift platform 15 may be first secured in position at a stage A by means ,of under-positioned, opposed, "channel support members 11 on which the platform rests. The support members 11 are removably, semi-permanently secured in position by suitable means, such as' U-bolts 12 and their associated nuts, to spacedapart, upwardly-extending leg members of the personnel tower 10. As the work progresses, the platform 15, as shown by the dot and the dot and dash lines of FIGURE 9, may be periodically raised to successive heights, represented by B and C, at which its traction machinery is securely-supported and is then employed.

for raising and lowering a conventional elevator or cage 50. It will be noted that when the building construction is completed, assuming, for example, that its height is attained when the lift platform 15 has reached the position of stage C, such, platform may then be lowered to the ground level 9 by the same means which is employed for raising it periodically, progressively or suc- 3 cessively to positions A, B and C. As shown, the elevator 50 has conventional slide fingers 50a that are adapted to ride along opposed side rails 51 in a conventional manner.

In FIGURES 1 to 3 of the drawings, I have shown operating or traction apparatus securely-mounted on a platform 15 of structure members, such as channel members. The traction machinery or apparatus includes a suitable drive means that may, for example, be a reversing electric motor 16 of an induction type. The motor '16 is provided with a bottom mounting flange 16:: that is secured on a mounting plate 15aof the platform 15 by any suitable means, such as conventional bolts. It will be noted that the lift platform or frame 15 also has mounting

plates

15b, 15c, 15d and 15e for other parts of the traction apparatus.

Referring particularly to FIGURE 4, the motor 16 has a drive shaft 16b on which a hub flange '25 is keyed or secured as part of an electromagnetic brake unit 17. In this connection, a conventional brake unit, such as manufactured by the Hollister-Whitney Company, is illustrated. The hub flange 25 is, in turn, secured as shown in FIG- URE 4, by bolt and nut assemblies to a brake hub part i 26 which carries a circumferential brake drum 26a. The part 26 has a frusto-conical bore therein and may be secured, as shown, by bolt, nut and washer assemblies on the end of a driven gear shaft 18 which has a complementary cone-shaped end portion that fits with such bore. The drive shaft 18 is journaled within and extends along hub portions 21 and 21a of a gear housing 20 and, at its outer reduced end, within a roller thrust bearing assembly 22. The driven shaft 18 has an intermediate or central worm portion 18a which meshes with and drives a worm gear wheel or ring 19 (see also FIGURE to provide a positive, forward and backward driven, reduction gear unit. The gear housing 20' has a mounting flange 20a which is secured on a mounting plate 150 of the platform 15. It will also be noted that the magnetic brake unit 17 has a flange 17a which is bolted to the mounting plate 1512.

As also shown in FIGURE 5, a cross-extending, relatively short-length, stationary support shaft 33 extends through the gear unit housing 20' at right angles to the driven shaft 18. At its one reduced end, the support shaft 33 is mounted within a boss mount portion 27 of a stand 28 and its other and further reduced end portion-is carried within an opposed boss mount portion 37 of an opposed stand 38. The stand 28 has a mounting flange 28a secured on the mounting plate 15d and the stand 38 has a mounting flange 38asecured on the mounting plate 15s.

A rotatable, driven, sheave spider, shaft, sleeve part or casting member 30, having a bore providing a clearance relation with the central portion of the stationary shaft 33, is positioned to extend therealong between the mounting

bosses

27 and 37 by end

thrust bearing assemblies

31 and 32. The bearing

assemblies

31 and 32 are bolted in position on the sleeve member 30 and rotatably-position the member on intermediate reduced portions of the support shaft 33. One end portion of the sleeve member 30 has a peripherally-projecting, circular or annular flange portion 30a to which the worm gear ring or wheel .19 is secure-d as by nut and bolt assemblies for actuating it in accordance with the actuation of the driven shaft 18.

The sleeve member 30 has a central cylindrical or annular portion 3012 that connects the flange portion 30a with a second, outwardly-projecting, circular or annular flange portion 30c adjacent its opposite end. A main elevator sheave 35 of annular or ring shape is secured as by bolt and nut assemblies in a stepped interlocking fitted relation therewith to project radially-outwardly therefrom. The sheaves 35 serves to carry and reeve a conventional elevator lift cable 52 (see also FIGURE 9) which, at one end, is shown connected by an eyelet 50b to an elevator cage 50. The cable 52, at its other end, carries a counterweight 53 that is elongated, in order that it may raise and lower within side spacing between the personnel elevator cage 50 and its side guide rails 51 to minimize the force required for raising the elevator ca e.

i winding drum 40 which may be termed an auxiliary or traction platform lift drum is carried on the central portions 30b of the rotatable sleeve member 30 for simultaneous rotation therewith during its actuation by the motor 16. The drum 40 represents an important feature of my invention in that it is the means utilized in cooperative association with the ordinary elevator cage lifting means for raising and lowering the platform 15 and its supported traction machinery or unit.

In FIGURES 6, 7 and 8 I have illustrated details of the construction of the drum 40. It is shown made in two substantially complementary parts that are adapted to have a complementary interfitting relation with each other to define an annular spool-like shape when securelymounted in position on the central portion 30b of the rotatable driven sleeve member 30. Each drum half has oppositely-positioned, radial-ly-outwardly-projecting, annular side flanges of

wings

41 and 41 for containing a lift cable 49 for the platform 15, Each part or half of the flange 41 is shown provided with a radially-inwardly- .projecting and converging edge slot 41a for receiving an end of the cable 49 and locking it in position therein. The flange portions 41 and 41' of each half are connected together in a spaced relation by a cylindrical sleeve or hub portion 42. As shown particularly in FIGURES 6 and 7, each half ofthe drum 4.0 has a central-outwardlyopen, offset or recess portion 42a therein that terminates in a mounting flange 42b. A headed, threaded bolt 43 is adapted to extend through a bore hole in the flange portion 42b and to be secured Within a threaded bore 42d of the other half of the drum 40. In this manner, the two halves of the drum 40 are tightly-secured about the portion 30b of the sleeve member 30.

It will be further noted that the sleeve member 30 is provided with a series of radially-projecting, quadrant lug portions 39d (see particularly FIGURES 5 and 8) which are adapted to have a complementary fit within wedge-shaped quadrant slots 44 and quadrant slot halves 44a of the drum parts. The slotted portions 44 and .4a are shown cut in the flange 41 adjacent the hub 42. This provides a positive latching or locking relation of the drum 40 on and with respect. to the member 30 for rotation therewith.

As shown in FIGURES 2 and 3, the housing 20 not only encloses the driven shaft 18 which has the worm portion 18a, but also the worm ring ear 19, a portion of the sleeve 30 and a portion of the stationary support shaft 33 (see also FIGURES 4 and 5). The housing 2% has, as shown in FIGURES 2 and 3, upper and lower halves or portions which have cooperating abutting flanges 23 that are removably-secured together by bolts 24. This facilitates the mounting of the enclosed parts as well as their maintenance. Although I have shown an eyelet as applied to the housing of the motor 316 as an attaching means for the one end of the auxiliary cable 49, it will be apparent that such end of the cable may be secured directly to the lift platform 15 or to any other suitable means secured to such platform provided that, as shown in FIGURE 9, the cable 49 may be properly reeved over the overhead idler pulley 46 and connected at its ends in a substantially balancing relation with respect to the platform 15.

In the ordinary operation of the traction unit, the motor 16 will drive the shaft 16b, driven shaft 18, the sleeve 30 and the sheave 35 'to raise the elevator cage 50', for example, from the ground level 9 of FIGURE 9 to an upper level A for the convenience of the personnel and the transportation of their materials and equipment. During this period, a secondary or auxiliary cable 49 is can ried by the drum 40 and is maintained in a wound-up relation thereon. However, when one stage of the building has been constructed, such as A, and it is desired to then move the platform 15 to position B, the support channels 11 are maintained in place at A, one end of the ca'ble 49 is unwound from the drum 4t), reeved over an idler pulley 46, and connected at such end to an eyelet 16c projecting from the housing of the motor 16.

It will be noted that the. idler pulley or sheave 46 is rotatably-mounted on an overhead platform 45 that is designated as a cathead and that, during theraising operation, is secured byend channel members 55 and clam-

ping bracket assemblies

56, 57 on riser or vertical tubular members of the scaffolding above the position, such as B, to which the platform is to be raised. At this time, the channels 11 whichare to support the platform 15 at its upper position B are not in position.

The motor 16 is actuated to, in turn, actuate the drum 40; as the cable 49 winds upon such drum 4f), the platform 15 andits associated supported traction machinery will be lifted to the position B. At this time, channels 11 may be secured in position therebeneath. After, the one end of the cable 49 has been disconnected from the eyelet 16c and rewound on the drum 40 with its end projecting through one of the slots 41a, the traction machinery may then be employed using its sheave 35 to raise and lower the elevator-cage 50 from the ground level 9 from stage A to a position below ,thestage B. As the work progresses, the platform 15 may be raised in the same manner in successive stages as indicated by position C of FIGURE 9. Beforeeffecting a raising of the platform 15 and its traction apparatus to a new height level or stage, I first move the elevator 50 to, for example, a lower position, such as the ground position of FIGURE 9. To minimize the load on the motor 16, I may also temporarily disconnect the lower end of the cable 52 from the elevator 50 and lower the counterweight 53. i y

In FIGURES l0 and 11, I have illustrated details of a suitable construction for the cat'head platform 45. This platform is provided with clamping brackets adjacent its opposite ends for adjustably and removably securing it at desired selected positions along the scaffold tower, above the traction apparatus. As shown, a pair of longitudinally-extending transversely-spaced apart structural or channel members 45a are adapted to extend slightly beyond opposite pairs of riser or vertical tubular members of the scaffolding 10 and are formed into a narrow platform by cross-extending, connecting, spacer pin members 45b. The sheave or idler pulley 46 is shown rotatably-positioned on a pin shaft 47 which is supported on upwardly-projecting mounts 48 that are secured at a central position on the members 45a. As shown particularly in FIGURE 10, each mount 48 has on outwardlyprojecting angle piece 48a that provides a lug-extension'upon which an associated end of the shaft 47 rests. Suitable means, such as nut and bolt assemblies 47a are adapted to extend through cross bores in each end of the shaft 47 to secure it on the lug extensions of the angle pieces 48a.

The platform 45 is secured adjacent its opposite ends on a pair of endwise-extending channel members 55 that carry mounts 55a adjacent their opposite ends and that project inwardly of the members 55 to support a fixed half or portion 56 of a clamping bracket made up of a fixed half 56 and a removable half 57. The clamping brackets have semi-circular inner contours so as to complementary engage and fit over or about an associated member of the scaffolding 10 and to be tightly clamped thereon by means of nut and bolt assemblies 58. As illustrated particularly in FIGURE 10, a group of bracket assemblies, three being shown, are mounted in an adjacent cooperating relation to extend vertically along the inside of each member 55 at each end thereof so as 6 to provide a positive and sure type of gripping engagement with the vertically-extending members of the scaffolding 10. It is thus apparent that the cathead 45 may be securely but removably and adjustably positioned at any suitable hei-ghtalong the extent of the scaffolding I In FIGURES 12 to 14, inclusive, I have illustrated a preferred construction and mounting of a traction unit supporting or lift platform, designated as 15. As disclosed in FIGURE 14;. the platform 15 maybe of rectangular form made up of a pair of spaced-apart longi tudinally-extending side channel members 60 and a pair of spaced-apart and transversely-extending end channel members 61, is suitably reinforced in their assembled relation by diagonally-extending. I-bearn members 62. The platform 15is providedwith opposite end pairs of clamping brackets for adjustably and removably securing it at desired, selected positions along the scaffold tower.

. It will be noted that the side structural members 60 extend endw i se beyond the transverse or end structural members 61 and are secured to mounting bracket assemblies at their opposite ends. It will be further noted that the mounting bracket assemblies cooperate'with ad- 1 jacent vertical tubular members of the scaffolding 10 its opposite ends which is adapted to be secured, as by nut and bolt assemblies 63, to an inner end portion of an extension plate member 64. The extension plate member 64, in turn adjacent its outer end, carries a verticallyspaced group of clamping bracket assemblies, each of which has an inner bracket half 65 secured by a mount 64a thereto and has an outer half or part 66 which is substantially complementary with the half 65 and which cooperates therewith to substantially surround an associated tubular riser member of the scaffolding 10. Nut

. and bolt assemblies 67 cooperate with end flanges of the folding construction of FIGURES 12 to 14, inclusive,

eliminates any clearance problems, particularly from the standpoint of the movement of the platform through the tower of the scaffolding 10. It also eliminates the necessity for having two sets of channels 11 (see FIG- URE 9) or, in the alternate, to the letting of the traction platform 15 han-g free when one set is moved from a lower to a higher level. The

halves

65 and 66 of the end or corner clamping brackets may be merely loosened when the platform 15 is to be raised and lowered so that they serve as guides along the vertical members of the scaffolding 10 during such movement. They can of course, be opened or removed when the platform 15 is to be raised or lowered beyond a joint of the scaffolding 10. l

Although for the purpose of illustration, I have shown and described an embodiment of my invention, it will be apparent to those skilled in the art that various modifications and changes may be made without departing from the spirit and scope of the invention, as indicated by the appended claims.

I claim:

1. Traction apparatus for mounting on an overhead lift platform to raise and lower an elevator and to raise and lower the lift platform which comprises, a drive motor, a gear reduction unit having a driven shaft operatively-connected to said motor for actuation thereby, a support shaft, means for carrying said support shaft, sleeve means rotata'bly-positioned on said support shaft and connected to said gear reduction unit for actuation thereby, said sleeve means having a sheave to carry cable reeving for raising and lowering the elevator, a winding drum operatively-associated with said sleeve means for rotation therewith on said support shaft, and said winding drum having means to secure one end of a winding cable thereto for raising the lift platform from one to a second stage of elevation.

2. A traction apparatus as defined in claim 1 wherein a pulley for the winding cable is carried in an overhead relation with respect to the traction apparatus, and means is carried on the lift platform for securing the other end of the winding cable thereto.

3. Traction apparatus as defined in claim 1 wherein said gear reduction unit has a worm actuated by said driven shaft and a worm gear actuated by said worm and operatively-connected to said sleeve means.

4. Traction apparatus as defined in claim 1 wherein,

said drive motor has a drive shaft, said driven shaft has a brake drum secured on one end portion thereof and coupled to said drive shaft, and said gear reduction unit has a cooperating worm and worm gear for restricting the actuation of said sleeve means to power actuation effected by said drive motor.

' 5. Traction apparatus as defined in claim 1 wherein, said driven shaft has a worm portion, a ring-shaped gear meshes with said worm portion and is securely connected to said sheave means for actuating it through the agency of said drive motor.

6. Traction apparatus as defined in claim 1 wherein, said sleeve means and said winding drum have cooperating tongue and groove portions for locking them in nonrotatable engagement with respect to each other, said drum is of two-part construction, and means cooperates with the two parts of said drum for removably-securing them together on said sleeve means.

7. Traction apparatus as defined in claim 1 wherein, a housing encloses said gear reduction unit and said driven shaft, said gear reduction unit has a worm meshing with a ring gear, said worm is carried by said driven shaft, one end portion of said support shaft extends through said housing, stands are positioned in a spaced relation with said housing to carry the opposite ends of said support shaft, said sleeve means is positioned on a central portion of said support shaft between said housing and one of said stands, bearing means is operatively-positioned between opposite end portions of said sleeve means and said support shaft for rotatably-positioning said sleeve means thereon, and said sleeve means has a central sleeve portion extending along said support shaft and at one end carrying said ring gear and at its other end carrying said sheave, and said winding drum is secured on said central sleeve portion of said sleeve means between said ring gear and said sheave for rotation therewith.

8. Traction apparatus for scaffolding to be mounted on an overhead lift platform to raise and lower an elevator and to periodically raise and lower the lift platform as work progresses which comprises, a drive motor, a gear reduction unit having a driven shaft operativelyconnected to said motor for actuation thereby, a support shaft, means for positioning said support shaft above and at substantially right angles to said driven shaft, sleeve means r-otatably-positioned on said support shaft and having means operatively-connecting one end portion thereof to said gear reduction unit for actuation thereby, said sleeve means having a sheave positioned on the opposite end thereof for receiving an elevator lift cable, and a winding drum securely-mounted on said sleeve means between said sheave and said operativelyconnecting means for receiving a platform raising and lowering cable.

9. Traction apparatus as defined in claim 8 wherein, said winding drum is of partible construction, and said sleeve means and said winding drum have cooperating tongue and groove portions for positively-securing said 8 winding drum on said sleeve means for rotation there with.

10. In a scaffold tower provided with a lift platform, traction apparatus secured on the platform and having a sheave, an elevator, a cable on the sheave connected at one end to the elevator and at its other end to a counterweight, and an overhead pulley wheel above the traction apparatus, wherein the traction apparatus comprises, a drive motor adjacent one end of the lift platform, a worm reduction gear unit adjacent an opposite end of the lift platform operatively-connected for actuation by said drive motor, a stationary shaft, a spindle rotatablypositioned on said stationary shaft and carrying an output gear of said gear reduction unit at one end thereof and the sheave at the opposite end thereof, a Winding drum securely-mounted on said spindle between said sheave and said output gear for rotation therewith, a lift cable carried by and having one end secured to said winding drum and adapted to reeve over the overhead pulley wheel, and means on said drive motor for securing the other end of said lift cable thereto.

11. In a scalfold tower as defined in claim 10 wherein, a lift platform is provided, said traction apparatus is positioned on said lift platform, and said platform has a pair ,of clamping assemblies projecting from opposite ends thereof to adjustably-secure said platform at selected vertical positions on the scaffold tower.

12. In a scaffold tower as'defined in claim 10 wherein, a cathead platform is provided, said overhead pulley wheel is operatively-positioned on said cathead platform, and said cathead platform has structural end members carrying clamping brackets projecting therefrom to ad justably-secure said cathead platform at selected vertical positions on the scaffold tower above said traction apparatus; a lift platform is provided, said traction apparatus is positioned on said lift platform, and said lift platform has clamping means adjacent its opposite ends to adjustably-secure said lift platform at selected vertical heights on the scaffold tower.

13. In a scaffold tower as defined in claim 10 wherein, said drive motor. is a reversible electrical motor having a drive shaft for rotating said spindle in opposite directions, said gear reduction unit has an input shaft, coupling means connects said drive shaft to said input shaft, a brake drum is carried by said coupling means, and a brake is operatively-positioned between said motor and said gear reduction unit to cooperate with said brake drum.

14. In a scaffold tower as defined in claim 13 wherein, said spindle has projecting quadrant-positioned lugs thereon adjacent the sheave, said winding drum has a References Cited by the Examiner UNITED STATES PATENTS 7/1953 North 1872 11/1965 Cannella 1872 SAMUEL F. COLEMAN, Primary Examiner.

H. C. HORNSBY, Assistant Examiner.

Claims

1. TRACTION APPARATUS FOR MOUNTING ON AN OVERHEAD LIFT PLATFORM TO RAISE AND LOWER AN ELEVATOR AND TO RAISE AND LOWER THE LIFT PLATFORM WHICH COMPRISES, A DRIVE MOTOR, A GEAR REDUCTION UNIT HAVING A DRIVEN SHAFT OPERATIVELY-CONNECTED TO SAID MOTOR FOR ACTUATION THEREBY, A SUPPORT SHAFT, MEANS FOR CARRYING SAID SUPPORT SHAFT, SLEEVE MEANS ROTATABLY-POSITIONED ON SAID SUPPORT SHAFT AND CONNECTED TO SAID GEAR REDUCTION UNIT FOR ACTUATION THEREBY, SAID SLEEVE MEANS HAVING A SHEAVE TO CARRY CABLE REEVING FOR RAISING AND LOWERING THE ELEVATOR, A WINDING DRUM OPERATIVELY-ASSOCIATED WITH SAID SLEEVE MEANS FOR ROTATION THEREWITH ON SAID SUPPORT SHAFT, AND SAID WINDING DRUM HAVING MEANS TO SECURE ONE END OF A WINDING CABLE THERETO FOR RAISING THE LIFT PLATFORM FROM ONE TO A SECOND STAGE OF ELEVATION.