US2662734A - Swing stage scaffold - Google Patents

Description

Dec. 15, 1953 R. ALLENBAUG SWING STAGE SCAFFOLD 2 Sheets-Sheet 1 Filed June 13, 1952 Dec. 15, 1953 R. ALLENBAUGH SWING STAGE SCAFFOLD 2 Sheets-Sheet 2 Filed June 15, 1952 Patented Dec. 15, 1953 swme STAGE SCAFFOLD Ralph Allenbaugh, Mansfield, Ohio, assignor of one-half to Wilberd F. Feigenbaum, Mansfield,

Ohio

Application June 13, 1952, Serial No. 293,322

20 Claims. (01; 254-176) This invention relates generally to swing stage scaffolds such as are used to support workmen and materials adjacent the exterior of a building or Wall while painting or otherwise working thereon. More specifically the invention relates to a power-operated mechanism by which a scaffold is raised and lowered as desired. This invention is a modification of the scaffold hoisting mechanisms shown in my co-pending application serial No. 102,488, filed July 1, 1949, and Serial No. filed November 6, 1950.

As shown herein, my improved swing stage scaffold comprises a pair of spaced similar stirrups and a swing stage plank which extends between and is carried by the stirrups. The stirrups are adjustably secured for up and down movement to two spaced single strands of cable which are secured to and extend downwardly from suitable supports which are mounted upon and extend outwardly from the top of a building or wall. Each stirrup has mounted thereon an electric motor operated mechanism which engages the associated strand of cable and is cnerativetomove the stirrup up and do n the cable and to hold the stirrup in any desired position.- The two mechanisms are identical and their construction is such that they in effect climb up and down the suspended cables when operated, and remain in fixed position on the cable when not operating. They operate independently of each other, and are power-operated in both directions so that the scaffold cannot be lowered by gravity. In case of a power failure while the scaffold is elevated the motors can be removed and manually operable cranks substituted therefor. means, which must be manually released while descending, is provided to prevent falling of the scaffold in the event the motor-operated mechanism is damaged to such an extent that itwill not remain in fixed position on the cable.

The principal object of the invention is to provide an improved swing stag scaffold which is constructed to be adjustably supported for up and down movement by two spaced single strands of rope or cable.

Another object of the invention isto provide a power-operated scaffold hoisting mechanism of light weight which is very efficient in operation, is of simple construction and is relatively inexpensive to manufacture. I

Other and more limited objects of the invention will be apparent from the following specification and the accompanying drawings forming a part thereof wherein: p v I Fig. 1 is an end elevation of a swing stage scatfold constructed according to myinventiong- Safety braking Fig. 2 is a front elevation of the lefthand end thereof;

Fig. 3 is a horizontal section taken substantially on the line 3-3 of Fig. 1;

Fig. 4 is a vertical section taken on the line 44 of Fig. 3;

Fig. 5 is an enlarged detail section through the safety braking means taken on the line 55 of Fig. 1;

Fig. 6 is a horizontal section taken on the line 6-6 of Fig. 5;

Fig. 7 is a view similar to Fig. 5 taken on the line '!-1 of Fig. 1; and I Fig. 8 is a horizontal section taken on the line 8-8 of Fig. 7.

Referring to the drawings by reference characters the numeral l indicates a swing stage plank which is carried by two spaced similar stirrups 2. The stirrups 2 are mounted for up and down movement upon a pair of cables 3 which are secured to'and hang down from a pair of fixed supporting members which extend outwardly from the top of a building or wall. Each stirrup 2 has permanently mounted thereon a hoisting mechanism which is generally indicated by the numeral 6 and is driven by any suitable electric power means 1. The hoisting mechanisms 6 are operative to move the stirrups 2 and the plank carried thereby up and down the cables 3 and to hold the stirrups 2 in fixed position on th cables 3 as desired. i

' With the exception that one is lefthand and the other right hand the stirrups 2 and the hoisting mechanisms 6 carried thereby are identicalin construction and operation. Consequently. only thejleft hand stirrup and hoisting mechanism are shown and described herein.

The stirrup 2 comprises a horizontally disposed cylindrical bar 10 having the upturned ends i which are permanently secured as by welding in the lower ends of upwardly extending tubular side rods l2. The tubular side rods [2 are disposed -in the same plane and extend vertically upwardly a short distance from the upturned ends l I of the bar In and then converge inwardly into engagement with opposite sides of a vertically slotted guide sleeve l3 to which the upper ends of the rods H are welded. The guide sleeve I3 is offset outwardly from the plane of the side rods H! a short distance so that a cable extending vertically downwardly from the sleeve I 3 will be spaced from the stirrup 2. Two spaced horizontal tubular braces l4 and 15 extend between the rods l2 and are welded thereto. A tube It is rotatably mounted upon the bar Hi between collars 11 which are welded to the bar I0, one

adjacent each end thereof. A pair of spaced parallel upwardly extending bolts |8 are rigidly secured to the tube I6, one adjacent each end thereof. The plank I is seated on the tube l6 and is clamped firmly thereto by a clamping bar H], which is slidably mounted upon the bolts l8, and a pair of wing nuts 20 threaded onto the bolts III. This means of clam ing the plank to the stirrups 2 makes it possible to rais one stirru higher than the other without danger of the plank sliding out of the stirrups. A bracket 2| in which a back bar or guard rail 22 is mounted is welded to and extends forwardly from one of the upwardly extending rods l2 near the upper end thereof. Pins 23 which are inserted through apertures in the back bar 22 prevent the back bar from sliding out of the brackets 2|.

The hoisting mechanism 5 comprises a gear case 25 which is rigidly secured to the cross braces I4 and I5 by suitable clamping means 26. A horizontal shaft 21 which is perpendicular to the plane of the stirrup 2 is rotatably mounted upon anti-friction bearing 28 carried by the case 25. A worm gear 29 which is keyed to the shaft 21 within the case 25 between the bearings 28 meshes with a worm 30 mounted upon a vertical drive shaft 3| which is rotatably supported by anti-friction bearing 32 carried by the case 25. The shaft 3| extends out through the top of the case 25 and terminates in a triangular section 33. The shaft 3| is driven in either direction by the electric power means 1 which is detachably connected to the triangular end 33 of the shaft 3|.

As shown herein the electric power means '1 consists of a standard electric drill which is available on the open market. It comprises a reversible motor 35 having the hand grips 36, 31 and 38 secured thereto. Speed reduction gearing 39 is mounted in a casing 40 secured to the lower end of the motor 35. The motor 35 drives, through the reduction gearing 33, a chuck 4| by which the power means 1 as a whole is connected to the end 33 of the shaft 3|. The power means 'I is removably secured in place with the chuck 4| gripping the end 33 of the shaft 3| by a clamp 42 which secures the free end of the hand grip 31 to one of the uprights I2 and a screw 43 which secures the hand grip 35 to a bracket 44 carried by the other upright I2. The operation of the motor 35 is controlled by a switch which is actuated by a trigger 45 in the hand grip 35. The direction of rotation of the motor 35 is controlled by a reversing switch which is actuated by finger lever 46. Current is supplied to the motor 35 from any suitable source through a long extension cord 41.

A drum 50 and a traction pulley 5| are keyed to the projecting end of the shaft 21 with the drum 50 adjacent the housin 2 T e drum 5 has end flanges 52 Which are spaced far enough apart for the cable 3 to be wound around the drum 50, between the end flanges, a plurality of turns. The pulley abuts the outer end of the drum 50 and has a single peripheral groove 53 the base of which is the same diameter as the diameter of the drum 50, between the end flanges 52, so that the base of the groove 53 and the outer surface of the drum 50 will have the same peripheral speed when rotated in unison by the shaft 21. As shown herein the drum 50 and traction pulley 5| are made as separate units, but if desired the traction pulley can be formed integrally with the drum 50. The drum 50 is disposed a short distance outwardly from the stirrun 2, and the gear case 25 and power mechanism '1 are disposed inwardly of the stirrup 2 as clearly shown in Figs. 2 and 3.

A bell crank lever 54 having the angularly disposed arms 55 and 56 is pivotally mounted on a stud 51 carried by a bracket 58 which is rigidly secured to the cross brace IS in spaced relation rea-rwardly of the drum and traction pulley 5|. The arm extends upwardly and rearwardly from the pivot stud 51 and the arm 56 extends upwardly and forwardly from the upper end of the arm 55. A grooved idler pulley 60 is rotatably mounted upon a pivot stud 6| carried by the bell crank lever 54 near the junction of the arms 55 and 56. A thin pressure wheel 62 is rotatably mounted upon a pivot stud 63 which is carried by the bell crank 54 at the free end of the arm 55, The idler pulley 50 is disposed rearwardly of the drum 50 and the pressure wheel 62 is disposed directly rearwardly of the traction pulley 5| so that it extends into the groove 53 in the traction pulley 5| during operation.

In use the cable 3 extends down through the slot 65 in the guide sleeve I3 and around the drum 50 a plurality of turns. From the top of the drum 5|! the cable extends to the top of the idler pulley 6|! and substantially half way therearound. From the bottom of the idler pulley 60 the cable 3 extends to the bottom of the traction pulley 5| and then substantially three quarters of the way around the traction pulley. From the traction pulley 5| the cable 3 hangs loosely downwardly from between the pulley 5| and the pressure wheel 62. After leaving the traction pulley 5| the cable 3 extends through a slotted guide sleeve 63, similar to the sleeve l3, which is secured to and outwardly of the cross beam l5 by arms 64. When the motor 35 is running the drum 56 and traction pulley 5| will be rotated in unison through the reduction gearing 39, worm 30, worm gear 23 and shaft 2I. When the motor 35 is running in one direction the cable 3 is wound onto the drum 50 at the end thereof adjacent the stirrup 2 and is withdrawn from the other end thereof and around the idler pulley 50 by the traction pulley 5|. Since the diameter of the drum 50 and the diameter of the base of the trac tion pulley groove 53 are the same the cable is withdrawn from the drum 5:) at the same linear speed that it is wound onto the drum. When the motor 35 is running in the opposite direction the cable 3 is fed around the idler pulley 60 and onto the outer end of the drum 50 by the traction pulley 5|. From this it will be apparent that when the drum 50 and traction pulley 5| are being rotated counterclockwise as viewcd in Fig. l the stirrup 2 will climb up the cable 3, and when rotated clockwise the stirrup will descend the cable 3. The construction of the worm 30 and worm gear 29 with which the worm meshes is such that they will lock the shaft 2'! against rotation when the motor 35 is not running.

During use the cable 3 must be maintained taut upon the drum 50 and traction pulley 5| at all times so that there will be no slippage between the cable and the drum 50 and/or the pulley 5|. The pull on the lower stretch of the cable 3, after it leaves the drum 50, necessary to maintain it taut upon the drum is very slight being at the most two or three pounds. The idler pulley 60 and the pressure wheel 62 mounted upon the bell crank 54 are provided for this purpose. The pressure wheel 52 holds the cable 3 tight against the traction pulley 5| and the idler pulley 60 guides the cable 3 from the drum 5' onto the traction pulley The idler pulley 60 and the cable 3 passing therearound cooperate to rock the bell crank 54 towards the drum 5!! and thereby urge the pressure wheel 62 toward the traction pulley 5i so as to firmly grip the cable between the pressure wheel 62 and pulley 5!. Obviously the greater the weight suspended by the upper stretch of the cable, the tighter the cable will be gripped between the pressure wheel and traction pulley.

In order to retain the cable 3 in the slots t5 and B6 of the guide sleeves l3 and 63 and to provide braking means which will prevent dropping of the stirrup 2 in the event the hoisting mechanism 6 becomes disabled I provide a brake t! which is carried by the guide sleeve 53 and a similar brake 53 which is carried by the guide sleeve 63. The brake 5! comprises a disc to which is eccentrically mounted upon a removable pin "ii! carried by a pa? of ears H secured to and extending outwardly from the sleeve it one on each side of the slot 55. The disc 69 has an actuating arm 12 formed integrally therewith and extending outwardly therefrom. The brake 63 comprises a disc 53, similar to the disc 69, which is eccentrically mounted upon a removable pin M carried by a pair of ears '55 which are secured to and extend outwardly from the sleeve 33 one on each side of the slot The disc 53 has an actuating arm it formed integrally therewith and extending outwardly therefrom sub stantially parallel to the arm '52. The arms '52 and "F6 are tied together by a link H which is pivotally secured to the outer ends of the arms. A handle 13, by which the link ll is raised to release the brakes Si and 58 in unison, is secured to the link Ti and extends inwardly therefrom into position to be readily grasped by an operator. The arrangement is such that the weight of the arms 12 and E6, the link ll and the handle is always bias the brakes 6i and 68 into locking engagement with the cable In descending the brakes 6i and 83 must be manually held in re leased position by the handle '58 and link Tl.

While both of the brakes i5? and (i3 cooperate -31 to hold the stirrup 2 in fixed position upon the cable 3, the primary purpose of the lower brake 68 is to prevent fouling of the cable 3 upon the drum 5% and pulleys 5i and so. In descending the traction pulley 5! in effect raises the lower stretch of the cable 3 and feeds it onto the drum 59, but since the stirrup 2 and. the hoisting mechanism carried thereby are moving downwardly at the same rate that the traction pulley iii is tending to lift the lower stretch of the cable 3 there is no upward movement of the lower stretch of cable. But if only the upper brake 5? were provided the operator might forget to release the upper brake when attempting to descend in which case the upper brake ti would hold the stirrup stationary and then the traction pulley would actually lift the lower stretch of the cable and foul it around the drum and pulley.

If desired the operating mechanism may be enclosed by a suitable removable cover which will prevent workmen from getting their hands or clothing caught therein. Such a cover will also prevent damage to the mechanism by falling articles.

From the foregoing it will be apparent to those skilled in this art that I have provided a very simple and efficient mechanism for accomplishing the objects of the invention.

t is to be understood that I am not limited to the specific construction shown and described 6. herein as various modifications may be made therein Within the scope of the appended claims,

What is claimed is:

1. A swing stage scaffold comprising a suspended cable, a stirrup adapted to support a plank, a guide sleeve through which said cable passes carried by said stirrup at the upper end thereof, a gear case carried by said stirrup below said guide sleeve, a shaft rotatably mounted in said gear case with one end thereof extending out from said gear case, power means by which said shaft is rotated in either direction carried by said gear case, a drum about which said cable is wounda plurality of turns after it leaves said guide sleeve, a traction pulley around which said cable passes after leaving said drum, said drum and said'traction pulley being secured to the extending end of said shaft, a lever having one end thereof'pivotally secured to said stirrup, a pressure wheel carried by said lever in alignment with said traction pulley, an idler pulley carried by said lever in offset relation to said pressure wheel, said idler pulley being operative to guide said cable onto said traction pulley after it leaves said drum, said pressure wheel being operative to hold said cable tight against said traction pulley, and said traction pulley being operative to withdraw said cable from one end of said drum at the same linear speed that said cable is be ing wound onto the other end of said drum.

2. A swing stage scaffold as defined in claim 1 in which said stirrup comprises a horizontally disposed bar adapted to support one end of a plank, and two upwardly extending side rods the upper ends of which are permanently secured to said guide sleeve. I

3. A swing stagescaifold as defined in claim 1 in which said guide sleeve is vertically slotted for the reception of said cable and has connected therewith detachable means operative to hold said cable in said slot.

4. A swing stage scaffold as defined in claim 1. in which said guide sleeve is vertically slotted for the reception of said cable and has a safety brake connected therewith which is operative to hold said cable in said slot and to prevent falling of said stirrup.

5. A swing stage scaffold as defined in claim 4 in which said safety brake comprises an eccentrically mounted disc which extends into said slot into engagement with said cable.

6. A swing stage scaffold as defined in claim 1 in which said power means comprises a worm gear secured to said shaft within said gear case.

' a worm rotatably mounted in said case in mesh with said worm gear, and an electric motor detachably connected to said worm.

'7. A swing stage scaffold comprising a suspended cable, a stirrup adapted to support a plank, a guide sleeve through which said cable passes secured to said stirrup adjacent the upper end thereof, a gear case mounted upon said stirrup in spaced relation to said guide sleeve, a shaft rotatably mounted in said gear case with one end thereof extending out from said gear case, power means by which said shaft is rotated carried by said gear case, a drum about which said cable is wound a plurality of turns after it leaves said guide sleeve, a traction pulley around which said cable passes after it leaves said drum, said drum and said traction pulley being rigidly secured to the extending end of said shaft, a shiftable member movably mounted upon said stirrup, a pressure wheel carried by said shiftable member in alignment with said traction pulley, an idler pulley carried by said shiftable member in offset relation to said pressure wheel, said idler pulley being operative to guide said cable onto said traction pulley after it leaves said drum, said pressure wheel being operative to hold said cable tight against said traction pulley, and said traction pulley being operative to withdraw said cable from one end of said drum at the same linear speed that said cable is being wound onto the other end of said drum.

8. A swing stage scaffold as defined in claim 7 in which said stirrup comprises a horizontally disposed bar adapted to support one end of a plank, and two upwardly extending side rods the upper ends of which are permanently secured to said guide sleeve.

9. A swing stage scaffold as defined in claim 7 in which said guide sleeve is vertically slotted for the reception of said cable and has connected therewith detachable means operative to hold said cable in said slot.

10. A swing stage scaffold as defined in claim 7 in which said guide sleeve is vertically slotted for the reception of said cable and has a safety brake connected therewith which is operative to hold said cable in said slot and to prevent falling of said stirrup.

11. A swing stage scaffold as defined in claim 10 in which said safety brake comprises an eccentrically mounted disc which extends into said slot into engagement with said cable.

12. A swing stage scaffold as defined in claim 7 in which said power means comprises a worm gear secured to said shaft within said gear case, a worm rotatably mounted in said case in mesh with said worm gear, and an electric motor detachably connected to said worm.

13. A swing stage scaffold comprising a suspended cable, a stirrup adapted to support a plank, upper and lower guide sleeves through which said cable passes carried by said stirrup in vertically spaced relation to each other, a driven drum around which said cable is wound a plurality of turns, a driven traction pulley around which said cable passes after leaving said drum, said drum and said traction pulley being disposed between said upper and lower guide sleeves, said traction pulley being operative when rotated in one direction to withdraw said cable from said drum and when rotated in the opposite direction to feed said cable onto said drum, a first brake carried by said upper guide sleeve and operative in braking position to grip said cable and hold said stirrup in fixed position on said cable, a second brake carried by said lower guide sleeve and operative when in braking position to grip said cable and prevent said traction pulley feeding said cable onto said drum.

14. A swing stage scaffold as defined in claim 13 in which said second brake is also operative when in braking position to grip said cable and hold said stirrup in fixed position on said cable.

15. A swing stage scaffold as defined in claim 14 in which said first brake and said second brake are connected together for actuation in unison.

16. A swing stage scaffold as defined in claim 13 in which said first brake and said second brake each comprises an eccentricall mounted disc pivotal on its respective sleeve extending into a slot in the sleeve and into engagement with said cable.

17. A swing stage scaffold as defined in claim 13 in which both of said brakes are normally biased to braking position.

18. A swing stage scaffold as defined in claim 17 in which said first brake and said second brake are connected together for actuation in unison.

19. A swing stage scaffold as defined in claim 18 in which said first brake and said second brake each comprises an eccentrically mounted disc which extends into a slot in the associated sleeve and into engagement with said cable.

20. A swing stage scaffold as defined in claim 13 in which said first brake and said second brake are connected together for actuation in unison.

RALPH ALLENBAUGI-I.

References Cited in the file of this patent FOREIGN PATENTS Number Country Date 690,519 France June 23, 1930

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