US3643761A

US3643761A - Platform

Info

Publication number: US3643761A
Application number: US857519A
Authority: US
Inventors: Donald F Melton
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-09-12
Filing date: 1969-09-12
Publication date: 1972-02-22
Anticipated expiration: 1989-02-22

Abstract

This invention relates to a traveling suspended platform, for use with vertical work surfaces, which is stabilized against oscillation or sway while exerting relatively little force on the vertical work surface.

Description

EJfiEe States Ptent Melton 1 Feb. 22, 1972 [54] PLATFORM [56] References Cited [72] Inventor: Donald F. Melton, 899 West Highway 96, UNITED STATES PATENTS 55112 2,645,531 7/1953 Rector ..182/37 [22] Filed: Sept. 12, 1969 2,692,168 10/1954 Gregory 182/13 pp No: 85 ,519 2,710,418 6/1955 Putnam ..l82/l28 Primary Examiner-Reinaldo P. Machado Attorney-J. Vincent MartinJoe E. Edwards and M. H. (jay 52 11.5.0 ..1s2/19, 182/37, 182/142, [571 ABSTRACT 182/1 This invention relates to a traveling suspended platform, for [51] lnt.Cl ..E04g 3/10 use with vertical work surfaces, which is stabilized against [58] Field of Search 182/12, l3, 19, 142, 36, 37, oscillation or sway while exerting relatively little force on the 182/229, 14 vertical work surface.

11 Claims, 5 Drawing Figures bul q 1:2 1! 22 2 q :1; i if 2/ 15/ :11 I

PLATFORM Suspended platforms are a widely used means for affording workmen access to vertical work surfaces. In some operations, such as for example the painting, lining, or insulating of large storage tanks, a traveling suspended platform moving horizontally around the tank in either stepwise or continuous movement, would provide an advantageous means for moving workmen and supplies from one wall section where work has been completed to another section where it has not.

However, suspended platforms, and particularly traveling suspended platforms, have the disadvantage of instability. They tend to swing or oscillate in reaction to the movement of the workmen or the overhead support apparatus. These oscillations make work more difficult and may be dangerous to the workmen. Also, the instability problem increases with increased distance from the overhead support to the platform. Since. in some storage tanks, as for example the cryogenic storage tank disclosed in the US Pat. to Smith et al., No. 3,196,622, the tank walls may be 60 feet or more in height, the problem of eliminating instability in the platform should be solved if traveling suspended platforms are to be used. It is also desirable that the method used to stabilize the platform not require the exertion of substantial forces on the tank walls, since in tanks such as the Smith cryogenic storage tank the walls may be covered by lining or insulation material which will not support heavy loading.

It is, therefore, an object of this invention to provide a suspended platform which may be used with a wall of any height without being subject to dangerous swaying or oscillations.

Another object is to provide a suspended platform adapted to travel horizontally across a wall at a constant rate of speed without substantial swaying or oscillation.

Another object is to provide such a platform which requires no structural connection to the wall, which exerts relatively little pressure on the wall, and which will travel freely therealong without damaging delicate coatings or insulation which may be on the wall.

Another object is to provide a suspended platform which is adapted to travel peripherally around the interior of a circular storage tank having a layer of insulation material thereon at a constant rate of speed without dangerous swaying or oscillation, and without exerting sufficient pressure on the tank walls to damage the insulation thereon.

These and other objects and advantages of the invention will become apparent from the drawings, specification and claims.

In the accompanying drawings which illustrate the preferred embodiment of the present invention, and wherein like numerals indicate like parts:

FIG. 1 is a view in elevation ofa platform and overhead trolley in accordance with the present invention;

FIG. 2 is a plan view ofthe platform ofFlG. 1;

FIG. 3 is an end view of the same platform;

FIG. 4 is an enlarged sectional view taken along line 44 of FIG. 3; and

FIG. 5 is a schematic illustration of the automatic limit switch used on the platform of the present invention.

The traveling suspended platform of the present invention is well suited for use in the construction of large insulated storage tanks, such as the cryogenic storage tank disclosed in the above referenced Smith patent. For convenience and clarity, this disclosure of the preferred embodiment of the present invention is made in relation to its use in the construction of such a cryogenic storage tank, although it may be utilized in conjunction with any wall.

An arcuate section of the circular wall of a large storage tank is indicated generally at 10, the concave side of wall representing the tank interior and the convex side representing the tank exterior. As shown, the wall 10 comprises two layers, a structural layer 10a of concrete or other suitable material, and a layer of insulation material 10!; disposed on the concave side of the structural layer 10a. The apparatus of the present invention may be viewed as being used to apply to the insulation layer 10b a vapor liner'material, a second layer of insulation material, etc,

Disposed on the concave side of wall 10, but spaced therefrom, are suitable platform retaining means. it is preferred that these consist of a plurality of vertical posts 12 spaced from each other and spaced approximately equidistant from the tank wall 10.

Disposed between the wall 10 and the platform retaining means is an overhead track 13, such as an l-beam, on which is supported a trolley; indicated generally at 14. The trolley has two end trucks 15 which ride on the track 13 with rollers 16. In addition to the rollers 16, the two end trucks 15 may mount other rollers (not shown) which stabilize the trolley by riding two outrigger beams (also not shown) running parallel to and on each side of the track 13. Power means for moving the trolley l4 horizontally along track 13 may be provided by a traction unit 17 mounted at one end of the trolley 14 and having a variable speed motor 18, and rollers 19 adapted to engage the track 13.

Spaced below the trolley is a platform, indicated generally at 20, which is basically rectangular in shape and is preferably constructed of aluminum for lightness. The platform 20 carries a safety railing 21, a central mast 22 and end masts 23 and 23a.

Means for suspending the platform 20 from the trolley 14 may be provided in the form of flexible metal cables 24. In the preferred form, two such spaced metal cables 24 depend from each of the two trolley end trucks l5 and have their lower ends wrapped on the drums of four hand winches 25 which are secured to the deck of platform 20. The platform 20 is therefore suspended in the annular region defined by the circular tank wall 10 and the concentric platform retaining means within the tank. The platform will travel horizontally around the annular region as the trolley 14 moves along the overhead track 13; and the platforms vertical position may be readily adjusted by the operation of hand winches 25 to increase or decrease the effective length of suspension cables 24.

Stabilizing means for the suspended platform is provided by expansible means mounted on the platform and adapted to simultaneously engage the wall 10 and the platform retaining meansin this case the spaced vertical posts 12. In the preferred form, these expansible means comprise two units: A wall-engaging unit, indicated generally at 26, and adapted to engage the tank wall 10; and a roller carrier beam 27 disposed on the opposite side of platform 20 and adapted to engage the spaced vertical posts 12. One of the wall-engaging unit 26 and beam 27, preferably the wall-engaging unit, is fixed to the platform.

The wall-engaging unit 26 includes an elongate member 29 preferably disposed with its horizontal axis parallel to that of the platform. The member 29 is rigidly attached to a crossbeam 28 mounted on the platform central mast 22 a suitable distance above the platform deck. Two pneumatic tire wheels 30 are mounted, one near each end of the elongate member 29 on the side facing the tank wall 10, and are adapted to rollably engage the insulation layer 10b of tank wall 10 as the platform moves horizontally around the tank.

The second part of the platform stabilizing means is a roller carrier beam 27 which is movably mounted on the platform and adapted to engage the vertical posts 12. The beam 27 is elongated and arcuate, being contoured to follow the line of posts 12, and is of a length sufficient to be in contact with at least two of the posts 12 at all times, and preferably with three posts during transition from post to post. Roller carrier beam 27 has disposed along its edge adjacent the posts 12 a plurality of small rollers 32 which rollably engage the posts 12 as the platform moves around the tank. Only a few of these rollers are shown, but they, extend the length of beam 27. A larger roller 33 is mounted at each end of beam 27 to insure proper rolling engagement with each post 12 as the platform moves into engagement with a new post.

The roller carrier beam 27 is movably mounted on the platform central mast 22 and end masts-23 and 23a for free movemeat toward or away from the vertical posts 12. Referring to FIGS. 3 and 4, a bracket 34 extending perpendicularly from the back of beam 27 has a lower flange 35 which is confined between grooved bracket guides 36 and 36a mounted on crossbeam 28 of central mast 22. Thus, the bracket 34 can move freely only in the direction of the longitudinal grooves in the bracket guide 36. The beam 27 is attached to bracket 34 by a pivot 34a. This arrangement permits free movement of beam 27 toward or away from the vertical posts 12 and assures that no torque will be exerted by beam 27 to turn the platform relative to the wall. The end masts 23 and 23a, mounted one at each end of the platform 20, support the extremities of roller carrier beam 27. Rollers, not shown, ride on the top surface of

masts

23 and 230. These rollers allow beam 27 to move freely in the horizontal plane but not vertically.

Pressure exerting means are provided for resiliently urging the platform's expansible means away from each other and into simultaneous engagement with the tank wall and the vertical posts 12, so as to maintain the platform in a stable position. In the preferred form, this is accomplished with a pulley-and-weight arrangement. A pulley 37 is mounted on the bracket guides 36 and 36a. A flexible tension member 38, one end of which is attached to the free end of the roller carrier beam bracket 34, is passed over pulley 37 and on its lower end are hung weights 39. This creates a tension in line 38 which urges the roller carrier beam 27 away from the platform and toward the posts 12 with a force corresponding to the amount of weight 39. An equal force in the opposite direction is exerted on the platform 20 by the pulley 37. This reaction force urges the platform toward the tank wall 10 and thereby maintains the wheels of the wall-engaging unit in constant engagement with the insulation layer 10b of tank wall 10. The force which the roller carrier beam 27 exerts against the vertical posts 12 and the force which the wall-engaging wheels 30 exert against the insulation layer 10b can be readily adjusted merely by changing the weight 39 suspended from pulley 37.

An idler wheel 31 is mounted near each end of the platform 20 on the side adjacent the tank wall 10 to prevent the platform body from engaging and damaging the insulation layer 1011 should the platform momentarily tip.

Although the simultaneous engagement of the tank wall and the platform-retaining means by expansible means associated with the platform will greatly stabilize the platform, providing stabilization when the platform and trolley are moving circumferentially with respect to the wall, against platform oscillation may be obtained by driving the platform 20 horizontally along the tank wall 10 at the same rate as the trolley 14 moves along the overhead track 13. While this may be accomplished in any desired manner, we prefer to accomplish it by using a variable speed motor 40 mounted on the wall-engaging unit 26 to drive the pneumatic tire wheels 30 which are in contact with the tank wall 10. The variable speed motors on the trolley and the platform should be set at speeds such that the trolley and platform will move about the tank at approximately the same rate.

To assure perfect synchronization of the trolley and platform, sensing means may be provided, associated with the flexible suspension cables 24, which are adapted to sense when the platform body is out of plumb with respect to the overhead trolley 14 and automatically adjust the relative rates of travel of the trolley and the platform to bring them back into plumb relationship. This is accomplished with

limit switches

41 and 43, indicated schematically in FIG. 4. The switches are disposed one on each side of one of the platform suspension cables 24 and are actuated by contact with the cable. As long as the platform hangs plumb with the trolley, neither switch is operated, If the trolley is driven faster than the platform, the platform lag switch 41 will be contacted by cable 24 and will operate through a voltage-varying device indicated generally at 43 to slightly reduce the speed of the trolley motor 18. If the trolley is operating too slowly, the platform lead switch 42 will be contacted by cable 24 and will operate through the voltage-varying device 43 to slightly speed up the trolley motor 18. Of course, the choice of whether to vary the speed of the trolley motor or the platform motor is arbitrary.

From the foregoing it can be seen that the present invention constitutes an improved type of traveling suspended platform wherein the platform has expansible means for simultaneously engaging both the wall and a retaining means to greatly reduce platform instability while exerting relatively little force on the wall; and the platform and its overhead support means may be driven at the same speed to virtually eliminate sway and oscillation of the platform.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the i]- LII lustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

1. An apparatus comprising:

A trolley adapted to be supported on an overhead track disposed between a substantially vertical wall and substantially vertical platform-retaining means spaced horizontally from said wall;

a platform;

means for suspending said platform from said trolley, said platform being suspended between said wall and said retaining means;

stabilizing means for said platform comprising,

expansible means on said platform for simultaneously engaging said wall and said retaining means, and

pressure-exerting means for resiliently urging said expansible means into simultaneous engagement with said wall and said retaining means.

2. The apparatus of claim 1 wherein:

said expansible means comprises,

means fixed on the platform for engaging one of the wall and the retaining means, and

means movably mounted on the platform for engaging the other of the wall and the retaining means.

3. The apparatus of claim 1 wherein said expansible means carries roller means to rollably engage said wall and said retaining means.

4. The apparatus of claim 1 wherein said trolley has powered motive means associated therewith for moving said trolley along said overhead track.

5. An apparatus comprising:

A trolley adapted to be supported on an overhead track disposed between a wall and a retaining means spaced from said wall;

powered motive means associated with said trolley for moving said trolley along said overhead track;

a platform;

flexible means for suspending said platform from said trolpowered wall-drive means fixed to said platform and adapted to engage said wall and urge said platform substantially horizontally therealong;

roller-carrier means movably mounted on said platform and adapted to rollably engage said retaining means;

pressure-exerting means for resiliently urging said walldrive means and said roller-carrier means away from each other and into engagement, respectively, with said wall and said retaining means; and

sensing means associated with said flexible means and adapted to sense when said platform body is out of plumb with respect to said overhead trolley and automatically adjust the relative rates of travel of said trolley and plat- 'form to bring said trolley and said platform back into plumb relationship.

6. The apparatus of claim 5 wherein:

Said sensing means comprises limit switches disposed on opposite sides of said flexible means and adapted to be actuated by contact with said flexible means as it moves from a vertical to a nonvertical position.

71 A traveling platform for use with a vertical wall, comprising a platform,

platform-retaining means comprising a plurality of substantially vertical posts spaced from each other in a line and spaced approximately equidistant horizontally from said wall,

a trolley movably supported on a track disposed over said platform and between said wall and said retaining means,

means for suspending said platform from said trolley and between said wall and said retaining means,

stabilizing means for said platform comprising expansible means on said platform for simultaneously engaging said wall and said retaining means, and

pressure exerting means for resiliently urging said expansible means into simultaneous engagement with said wall and said retaining means.

8. The apparatus of claim 7 wherein said expansible means comprises,

means fixed on the platform for engaging one of the wall and the retaining means, and means movably mounted on the platform for engaging the other of the wall and the retaining means. 9. The apparatus according to claim 8 wherein said means to engage said retaining means includes,

an elongated beam longitudinally contoured to follow the line of said spaced posts, the length of said beam being sufficient to be in contact at all times with at least two of said posts. 10. The apparatus according to claim 7 wherein, said expansible means carries roller means to rollably engage said wall and said retaining means. 11. The apparatus ofclaim 7 wherein, said trolley has powered motive means associated therewith for moving said trolley along said overhead track.

Claims

1. An apparatus comprising: A trolley adapted to be supported on an overhead track disposed between a substantially vertical wall and substantially vertical platform-retaining means spaced horizontally from said wall; a platform; means for suspending said platform from said trolley, said platform being suspended between said wall and said retaining means; stabilizing means for said platform comprising, expansible means on said platform for simultaneously engaging said wall and said retaining means, and pressure-exerting means for resiliently urging said expansible means into simultaneous engagement with said wall and said retaining means.

2. The apparatus of claim 1 wherein: said expansible means comprises, means fixed on the platform for engaging one of the wall and the retaining means, and means movably mounted on the platform for engaging the other of the wall and the retaining means.

5. An apparatus comprising: A trolley adapted to be supported on an overhead track disposed between a wall and a retaining means spaced from said wall; powered motive means associated with said trolley for moving said trolley along said overhead track; a platform; flexible means for suspending said platform from said trolley; powered wall-drive means fixed to said plAtform and adapted to engage said wall and urge said platform substantially horizontally therealong; roller-carrier means movably mounted on said platform and adapted to rollably engage said retaining means; pressure-exerting means for resiliently urging said wall-drive means and said roller-carrier means away from each other and into engagement, respectively, with said wall and said retaining means; and sensing means associated with said flexible means and adapted to sense when said platform body is out of plumb with respect to said overhead trolley and automatically adjust the relative rates of travel of said trolley and platform to bring said trolley and said platform back into plumb relationship.

6. The apparatus of claim 5 wherein: Said sensing means comprises limit switches disposed on opposite sides of said flexible means and adapted to be actuated by contact with said flexible means as it moves from a vertical to a nonvertical position.

7. A traveling platform for use with a vertical wall, comprising a platform, platform-retaining means comprising a plurality of substantially vertical posts spaced from each other in a line and spaced approximately equidistant horizontally from said wall, a trolley movably supported on a track disposed over said platform and between said wall and said retaining means, means for suspending said platform from said trolley and between said wall and said retaining means, stabilizing means for said platform comprising expansible means on said platform for simultaneously engaging said wall and said retaining means, and pressure exerting means for resiliently urging said expansible means into simultaneous engagement with said wall and said retaining means.

8. The apparatus of claim 7 wherein said expansible means comprises, means fixed on the platform for engaging one of the wall and the retaining means, and means movably mounted on the platform for engaging the other of the wall and the retaining means.

9. The apparatus according to claim 8 wherein said means to engage said retaining means includes, an elongated beam longitudinally contoured to follow the line of said spaced posts, the length of said beam being sufficient to be in contact at all times with at least two of said posts.

10. The apparatus according to claim 7 wherein, said expansible means carries roller means to rollably engage said wall and said retaining means.

11. The apparatus of claim 7 wherein, said trolley has powered motive means associated therewith for moving said trolley along said overhead track.