US3752263A

Movatterモバイル変換

Info

Publication number: US3752263A
Application number: US00216372A
Authority: US
Inventors: H Thevenot
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-01-10
Filing date: 1972-01-10
Publication date: 1973-08-14
Anticipated expiration: 1990-08-14

Abstract

A cage is mounted for reciprocation vertically in a scaffold or framework. An electric motor is secured to the cage together with a reduction gear box. A drive sprocket and an idler sprocket are mounted on said cage, the drive sprocket being connected to the electric motor. A further idler is journalled at the top of the scaffold and a sprocket chain is anchored by one end thereof to the cage. It extends upwardly of the scaffold, over the idler at the top of the scaffold and then back down to the cage whereupon it engages around the idler on the cage and around the drive sprocket so that the other end of the chain loops freely and is supported on the cage for convenience. Rotation of the drive sprocket pulls the cage up and down the scaffold with friction and mechanical advantage remaining constant.

Description

United States Patent [1 1 Thevenot ELECTRIC TRAVELLING POWERED MAINTENANCE SCAFFOLD Inventor: Henry Thevenot, 589 Spence St.,

Winnipeg, Manitoba, Canada Filed: Jan. 10, 1972 Appl. N0.: 216,372

[ Aug. 14, 1973 Primary Examiner-Reinaldo P. Machado Att0rney-Stanley G. Ade

[57] ABSTRACT A cage is mounted for reciprocation vertically in a scaffold or framework. An electric motor is secured to the cage together with a reduction gear box. A drive sprocket and an idler sprocket are mounted on said cage, the drive sprocket being connected to the electric motor. A further idler is journalled at the top of the scaffold and a sprocket chain is anchored by one end thereof to the cage. It extends upwardly of the scaffold, over the idler at the top of the scaffold and then back down to the cage whereupon it engages around the idler on the cage and around the drive sprocket so that the other end of the chain loops freely and is supported on the cage for convenience. Rotation of the drive sprocket pulls the cage up and down the scaffold with friction and mechanical advantage remaining constant.

10 Claims, 6 Drawing Figures Patented Aug. 14, 1973 3 Sheets-Sheet. I.

FIG.

Patented Aug. ,14, 1973 5 Sheets-Sheet 3 FIG. 6

FIG. 3

FIG. 4

Patented Aug. 14, 1973 3,752,263

3 Sheets-Sheet 5 Mus/a FIG. 5

BACKGROUND OF THE INVENTION This invention relates to new and useful improvements in travelling scaffolds used primarily for maintenance in buildings or the like although, of course, the device can be used for other purposes.

Such scaffolds are usually manually operated or hydraulically operated due to the fact that electrically operated scaffolds normally require a relatively heavy duty electric motor which makes the cost excessive apart from the fact that heavy duty motors of relatively large horsepower cannot be operated from conventional power outlets.

The reason for the requirement of heavy duty or large horsepower motors is due to the fact that such motors are usually stationary and transmit power to the platform or hoist cage either through chain and sprocket or cable so that when the platform or cage is the farthest distance from the electric motor, there are relatively large transmission losses due to friction, the weight of the cables and chains, and lack of mechanical advantage.

SUMMARY OF THE INVENTION The present device overcomes all of these disadvantages by providing a portable or movable maintenance scaffold having a cage or platform which moves vertically up and down the supporting structure and is provided with an electric motor which is secured to the cage or platform rather than the stationary scaffold.

By utilizing a chain and sprocket system in conjunction with a reduction gear box, it has been found that a one-fourth horsepower motor is adequate for normal operation due to the fact that the friction and other losses are constant throughout the entire length of travel of the cage or platform.

This enables a relatively light weight portable and economical maintenance scaffold to be provided which is entirely adequate for the majority of maintenance problems encountered in most buildings.

With the foregoing objects in view, and such other or further purposes, advantages or novel features as may become apparent from consideration of this disclosure and specification, the present invention consists of the inventive concept which is comprised, embodied, embraced, or included in the means, method, process, product, construction, composition, arrangement of parts, or new use of any of the foregoing, herein exemplified in one or more specific embodiments of such concept, reference being had to the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of the device.

FIG. 2 is a side elevation thereof.

FIG. 3 is a plan view of the platform.

FIG. 4 is a plan view of the base per se.

FIG. 5 is an enlarged section of the drive mechanism for the carriage or platform substantially along the line 5-5 of FIG. 1.

FIG. 6 is an enlarged fragmentary section along the line 6-6 of FIG. 2.

In the drawings like characters of reference indicate corresponding parts in the different figures.

DETAILED DESCRIPTION Proceeding therefore to describe the invention in detail, reference character 10 illustrates the base which consists of twolongitudinal members 11 in spaced and parallel relationship and maintained thereby a pair oftransverse members 12 extending therebetween and intermediate the ends as clearly shown in FIG. 4.

Castor wheel assemblies 13 are secured to each end of the longitudinals 11 as shown in the drawings thus enabling the device to be moved from one position to the other easily and readily. A conventional castor wheel brake indicated by reference character 13' is provided on one of the castor wheel assemblies.

Extending upwardly from thetransverse members 12 adjacent one member 1 1 is a vertical framework collectively designated 14 which consists of four

angle irons

15, 15A, braced by vertically lyingdiagonal braces 16 and horizontally extending

braces

17 and 17A.

This structure forms a three sided, vertically extending framework with the open side facing inwardly of the base and towards theother member 11.

Reference should be made to the angle irons specifically designated 15A, the flanges of which face inwardly towards one another as clearly shown in FIG. 4.

A cage or platform collectively designated 18 includes arectangular floor 19 andvertical guard structure 20 braced bydiagonals 21 andhorizontal members 22 thus forming a three sided wall structure. Asafety chain 23 extends between two of the vertical members and provides access to the cage for the operator.

A lower pair ofguide rollers 24 are journalled for rotation within the lower ends of a pair of spaced and parallelvertical members 24A which extend from the upper side to the lower side of the cage frame and on theinner wall 248 thereof. These members have a channel configuration when viewed in plan as seen in FIG. 6. Theseguide rollers 24 engage and bear against the outer surfaces 158 of the flanges of theangle irons 15A.

An upper pair ofguide rollers 25 are journalled for rotation within the upper ends ofmembers 24A and these guide rollers engage and bear against theinnerv surfaces 15C of the flanges of theangle irons 15A so that the cage is mounted for vertical reciprocation up and down theangle iron members 15A and is supported in a cantilever fashion therefrom (see FIGS. 4, 5 and 6).

A conventional U-shapedsafety brake assembly 26 cooperates between the flanges of theangle irons 15A and the cage if the drive chain breaks but as this is conventional in structure and operation, it is not deemed necessary to describe same in detail.

FIG. 5 shows details of the drive mechanism which consists of a source of power taking the form of anelectric motor 27 bolted to anangle iron 28 which in turn is secured to and assists in supporting thefloor 19 of the cage so that the electric motor is suspended below the cage as clearly shown.

A coupling 28' connectsdrive shaft 29 to inputshaft 30 of areduction gear box 31 also supported tomember 28 below thefloor 19 of the'cage.

An output ordrive shaft 32 extends from the reduction gear box at right angles to theshaft 30 and is provided with achain sprocket 33 secured thereto and rotatable therewith.

Anidler sprocket 34 is joumalled upon aspindle 35 which in turn is secured to a downwardly extendingsupport member 36 also depending from the underside of thecage 18.

Adjacent the upper end of the vertical scaffold orstructure 14, is a further idler sprocket 37 journalled upon aspindle 38 which is preferably provided with a roller bearing (not illustrated). Reference to FIGS. 1 and 2 show the position of this upper idler sprocket 37.

Achain 39 extends around the sprockets and oneend 40 of this chain is anchored by means ofclamp assembly 41 to the inner end ofmember 28, that is to the inner lower side of thecage 18 as shown in FIG. 5. The chain then extends upwardly and over the upper idler sprocket 37 and then downwardly and around the lower idler sprocket 34. It then extends upwardly and around the drive sprocket 33 and the free end or loopedportion 39A of the chain extends downwardly and then upwardly to be secured byend 42 to the underside of the cage as shown in FIG. 5.

An arcuatelycurved guide 43 extends around part of the periphery of thedrive sprocket 33 in order to maintain thechain 39 in contact with the drive sprocket and an angulated guide 44 is situated below drivesprocket 33 and maintains the desired separation between the substantially vertical runs of the chain upon each side thereof and prevents then wrapping around the drive sprocket.

In operation, the electric motor is controlled by means of aswitch assembly 45 within the cage. The motor is of course reversible and when it is operated to rotatedrive sprocket 33 in the direction of arrow 46 (see FIG. the cage will be moved upwardly with the excess chain forming a loop at 39A, until the cage reaches the uppermost limits of the scaffold orvertical structure 14.

By reversing the motor, the cage is lowered under power as desired.

Because the electric motor is always travelling with the cage, frictional losses are the same at either end of the travel and the mechanical advantage is also constant.

it will, of course, be appreciated than anelectric cable 47 extends freely from the electric motor to a convenient electrical plug and that the length of this cable is sufficient for same to be connected to the plug when the cage is at the uppermost position.

However, the fact that a fractional horsepower motor is used, means that a relatively lightweight cable is required so that even when fully extended, the weight thereof is slight.

Various modifications may be constructed or performed within the scope of the inventive concept disclosed. Therefore what has been set forth is intended to illustrate such concept and is not for the purpose of limiting protection to any herein particularly described embodiment thereof.

What I claim as my invention is:

l. A maintenance scaffold and the like comprising in combination a base, a vertically situated scaffold extending upwardly from said base and a cage in said scaffold, means mounting said cage for up and down movement in said scaffold, and power means cooperating between said cage and said scaffold for moving said cage up and down same, said power means including an electric motor mounted on said cage, a drive sprocket driven by said electric motor and upper idler means at the top of said scaffold, lower idler means on said cage, and a sprocket chain secured by one end thereof to said cage and extending operatively around both said idler means and said drive sprocket, said idler means taking the form of a chain sprocket journalled for rotation in said scaffold and said cage respectively, said idler sprocket on said cage being below said drive sprocket, said chain extending from said one end thereof, upwardly around said idler chain sprocket in said scaffold and then downwardly and around said idler chain sprocket and then up and over said drive sprocket.

2. The device according to claim 1 which includes an arcuately curved guide spaced from and extending around the upper side of said drive sprocket to maintain said chain in engagement therewith.

3. The device according to claim 1 which includes a further guide spaced from the underside of said drive sprocket to prevent said chain from wrapping around said drive sprocket.

4. The device according to claim 1 which includes a further guide spaced from the underside of said drive sprocket to prevent said chain from wrapping around said drive sprocket.

5. A maintenance scaffold and the like comprising in combination a base, a vertically situated scaffold extending upwardly from said base and a cage in said scaffold, means mounting said cage for up and down movement in said scaffold, and power means cooperating between said cage and said scaffold for moving said cage up and down same, said power means including an electric motor mounted on said cage, a drive sprocket driven by said electric motor and upper idler means at the top of said scaffold, lower idler means on said cage, and a sprocket chain secured by one end thereof to said cage and extending operatively around both said idler means and said drive sprocket, said means mounting said cage for vertical movement in said scaffold including a pair of spaced and parallel vertically extending members on said scaffold having inwardly facing flanges, channel means on said cage extending vertically thereof in spaced and parallel relationship and being spaced apart substantially the same amount as said vertically extending members, a lower roller journalled for rotation adjacent the lower end of each of said channel means, said rollers bearing against and engaging the outer surfaces of said flanges, and an upper roller journalled for rotation adjacent the upper end of each of said channel means, said upper rollers bearing against and engaging the inner faces of said flanges whereby said cage is mounted in a cantelever relationship with said scaffold.

6. The device according toclaim 5 in which said idler means taking the form of a chain sprocket journalled for rotation in said scaffold and said cage respectively, said idler sprocket on said cage being below said drive sprocket.

7. The device according toclaim 6 in which said chain extending from said one end thereof, upwardly around said idler chain sprocket in said scaffold and then downwardly and around said idler chain sprocket and then up and over said drive sprocket.

8. The device according to claim 7 which includes an arcuately curved guide spaced from and extending around the upper side of said drive sprocket to maintain said chain in engagement therewith.

9. The device according to claim 7 which includes a further guide spaced from the underside of said drive sprocket to prevent said chain from wrapping around said drive sprocket.

10. The device according to claim 8 which includes a further guide spaced from the underside of said drive sprocket to prevent said chain from wrapping around said drive sprocket.

I! i i

Claims

1. A maintenance scaffold and the like comprising in combination a base, a vertically situated scaffold extending upwardly from said base and a cage in said scaffold, means mounting said cage for up and down movement in said scaffold, and power means cooperating between said cage and said scaffold for moving said cage up and down same, said power means including an electric motor mounted on said cage, a drive sprocket driven by said electric motor and upper idler means at the top of said scaffold, lower idler means on said cage, and a sprocket chain secured by one end thereof to said cage and extending operatively around both said idler means and said drive sprocket, said idler means taking the form of a chain sprocket journalled for rotation in said scaffold and said cage respectively, said idler sprocket on said cage being below said drive sprocket, said chain extending from said one end thereof, upwardly around said idler chain sprocket in said scaffold and then downwardly and around said idler chain sprocket and then up and over said drive sprocket.

6. The device according to claim 5 in which said idler means taking the form of a chain sprocket journalled for rotation in said scaffold and said cage respectively, said idler sprocket on said cage being below said drive sprocket.

7. The device according to claim 6 in which said chain extending from said one end thereof, upwardly around said idler chain sprocket in said scaffold and then downwardly and around said idler chain sprocket and then up and over said drive sprocket.