US2598730A

US2598730A - Portable dock scaffold

Info

Publication number: US2598730A
Application number: US12844A
Authority: US
Inventors: John L Thompson; Bibb John
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-03-03
Filing date: 1948-03-03
Publication date: 1952-06-03
Anticipated expiration: 1969-06-03

Description

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PORTABLE DOCK SCAF'FOLD J. L. THOMPSON EIAL June 3, 1952 Filed March 5, 1948 June 1952 J. L. THOMPSON ETAL 2,598,730

PORTABLE DOCK SCAFFOLD Filed March 3. 1948 2 SHEETSSHEET 2 INVENTORS JOHN L. THOMPSON JOHN BIBB i W BY T? W ATTORNEY Patented June 3, 1952 PORTABLE DOCK SCAFFOLD John L. Thompson, Dial, and John Bibb,

Port Hueneme, Calif.

Application March 3, 1948, Serial No. 12,844

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 4 Claims.

'IShis invention relates to portable scaffolds, and more particularly to a portable scaffold capable of being positioned to give access to the underside of piers and docks.

Underneath a typical waterfront dock there are numerous operations which mustbeperiodically performed. Oil lines and other plumbing must :be repaired and inspected. Telephone wires and electric wiring often require servicing. Tension members holding posts and bollards often need tightening. Braces must often be shimmed as they shrink with the passage of time. The bolts and nuts which hold the timbers together often must be cleaned-and'painted. In addition, it is necessary to inspect the underside of docks as a matter of general preventive maintenance.

It is an object of this invention to provide a portable scaffold which may be readily moved into place beneath a .dock,whereby necessary operations under the dock may be performed.

It is another object of this invention to provide a'portable scaffold which may be simply and detachably mounted to the lift fork of a truck, which truck may'then be used to transport the scaffold to various locations and lower it into place underneath the dock.

It is another object of this invention to obviate the cost and time involved in constructing temporary-scaffolding under a dock, by using a completely portable scaffold which has no attachment whatever to the dock, being positioned in place solely by the proper disposition of the lift "truck which carries it about.

'It is a further object of this inventionflto provide a portable scaffold for use under docks whereby the safety, health, and convenience of maintenance and service personnel maybe enhanced.

In accordance with this invention, .the scaffold comprises a horizontal, generally elongate frame, from one end .of which depends :a pair of vertical frames. To the bottom edges of the frames is secured a horizontal platform extending beneath the horizontal frame. The horizontal frame includes .a pair of transverse girders, one of them being disposed at the end of the frame, the other -being spaced inwardly of the frame. The inward girder is secured to the frame in a plane slightly above that of the outward girder, so that the frame may beheld to the horizontal extending fork of a lift truck, with the outer girder disposed immediately under the fork, and theinward girder disposed ,above 2 supported in cantilever fashion, With the platform depending below the fork of the truck.

In use, the truck is driven to the edge of the dock, and stopped with the front wheels abutting the barricade timber. The fork is then lowcred, thereby lowering the entire scaffold over the edge of the dock. When the horizontal, upper frame is almost touching the timber, the truck is backed away until the vertical frame almost touches the edge of the dock, thus positioning the platform in under the dock.

A gangplank is telescopically mounted beneath the platform, so that it may be extended for added length, to enable the workmen to get in farther under the dock. A ladder is vertically secured between the horizontal frame and the platform to provide access to and fromthe platform when it is in position under the dock.

The horizontal frame is strengthened against bending by the provision of a vertical bridge frame secured transversely to and above the horizontal frame, which serves to mount an elongate member in the form ,of a T sectioned beam anchored at its respective ends to the ends of the horizontal frame, and extending up and over the edge of the bridge frame, to which it'is secured. In this way the effective section modulus of the horizontal frame is made great enough to accept the weight of the platform and th workmen thereon.

A preferred embodiment of the instant invention is'shown in the drawing, wherein:

Fig. 1 is a side View of the scaffold;

Fig. 2 is an end view thereof;

Fig. '3 is a detailed view showing the manner in which the telescoping gangplank is mounted beneath the platform;

Fig. 4 is a fragmentary enlarged view showing the mounting of a telescoped hand rail for the g-angplank;

Fig. 5 is a View showing the scaffold secured to its fork lift truck, in position to be lowered over the edge of the dock; ,and

Fig.6 is a view v,sllowing'thescaffold in use with the .gangplank extended to give maximum access to the underside of the dock.

Referring to Fig. 1, there is shown a horizontal frame H, comprised of .a pair of longitudinal channel beams i 2 secured together by transverse girders .I3 .M, .and 15. The girder L5 is disposed at one end of the frame 1 I and is attached to the bottom ,edge of the beams l2. The girder i4 is secured transversely of the frame H,:-inwardly of the gg-irder I15. is attached at the top'edge the 9f the fork. in this way the frame is cf themember l2- fIhe-two gi de s-J nd 1-5 to the lower edges of which is secured a horizontal platform I8 extending inwardly underneath the frame II, the general effect of the scaffold being that of a U tipped on its side. i The section modulus of the frame [I alone i not enough to support the overhanging weight of the structure depending therefrom. It is therefore necessary to strengthen the frame II by 1 securing thereabove' a vertical bridge frame 2|, 1 consisting of a pair of upright members 22 anchored to the respective beams I2 and bridged by a horizontal member 23. The frame 2| is strengthened by diagonals 24. Elongate tension members in the form of T sectioned beams 25 are secured at their respective ends to the ends of the frame I I, and extend up and over the edge of the vertical bridge 2|, to which they are secured as by welding at 25. The bridge member 2| is preferably disposed in the same vertical plane as that occupied by the transverse girder 4, thereby providing maximum section modulus for the given type of construction.

Tension members 3| are diagonally mounted within the vertical frame I! to lend added strength thereto. Similarly, diagonal members 32 are mounted between the two frames transversely of the scaffold at the end of the frame I 2,

to give strength to the assembly.

Beneath the platform [8, the two edges of which are formed of channel members 33 (Fi 3). is telescopically mounted a gangplank 34, which may be extended from the platform I8 as shown 3 inFig. 1 to give access farther in under the dock.

Balustrades 35 at the end of the platform provide for mounting hand rails 36, formed of angle iron,

in which are secured, as by welding, pipes 31 (Fig. 4) Telescopically within each pipe 31 is mounted another pipe 7 38, which constitutes a hand rail being supported by a balustrade 39 at the end of the gangplank 34. A hand rail 4| is secured transversely between the two balustrades 39 to prevent workmen from walking off the end of the gangplank 34.

A ladder 42 is mounted in one of the frames I! to provide ready access to and from the platform |8 when the scaffold is in position underneath a dock.

Operation Use of the instant invention will now be described. The no; fork I5 is first inserted between 1 edge of the clock 41, as shown in Fig. 5, the fork I6 is lowered until the platform I8 is substantially level with the dock 41.

At this point workmen may board the platform |8 under the rail 4|.

The fork I6 is then lowered further until the frame II is positioned just above the timber 46.

, for the gangplank 34, these hand rails in turn This brings the platform l8 well beneath the level of the dock 41, so that the truck 45 may then be backed up until the inner edges of theframes almost touch the edge of the dock 41. The fork I6 is then lowered until most of the weight of the scaffold rests on the timber 46, as shown in Fig. 6. The gangway 34 is then ready to be extended as shown in Fig. 6, so that a considerable length of elongate platform is provided under the dock 41.

Necessary repairs may then be made as required. The weight of the truck 45, coupled with the fact that the scaffold rests principally on the timber 45, serves to maintain the scaffold safely in position. Much of the work may be done with the center of gravity of the scaffold and its contents substantially beneath the front wheel of the truck 45, thereby providing a very stable and safe assembly. During operation, access to the platform I8 and the gangplank 34 is had by the ladder 42.

The invention described herein may be manufactured and used by or for the Government of the UnitedStates of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. A portable scaffold adapted to be carried by a lift truck, comprising a flat, horizontal, generally elongate frame including a pair of transverse girders, one of said girders being disposed at one end of said frame, the other girder being spaced from said one girder inwardly of said frame and in a plane slightly above said one girder, said frame being adapted to be held by the lifting fork of the truck in cantilever fashion with said one girder disposed under said fork and said other girder disposed over said fork, a verticalbridge frame secured transversely to and above said horizontal frame, an elongate tension member secured at its respective ends to the ends of said horizontal frame and secured intermediate its ends to the top of said bridge frame, a vertical frame secured to said horizontal frame at the overhanging end thereof and depending therefrom, and a horizontal platform secured to said vertical frame and extending beneath said horizontal frame.

2. A portable scaffold adapted to be carried by a lift truck, comprising a flat, horizontal, generally elongate frame including a pair of transverse girders, one of said girders being disposed at one end of said frame, the other girder being spaced from said one girder inwardly of said frame and in a plane slightly above said one girder, said frame being adapted to be held by the lifting fork of the truck in cantilever fashion with said one girder disposed under said fork and said other girder disposed over said fork, a pair of flat vertical frames secured respectively to opposite sides of said horizontal frame at the overhanging end thereof and depending therefrom, a horizontal, generally elongate platform secured to the lower ends of said vertical frames and extending beneath said horizontal frame, and a gangplank telescopically mounted beneath said platform and selectively extendable away from said vertical frame.

3. A portable scafiold adapted to be carried by a lift truck, comprising a fiat, horizontal, generally elongate frame including a pair of transverse girders, one of said girders being disposed at one end of said frame, the other girder being spaced from said one girder inwardly of said frame and in a plane slightly above said one girder, said frame being adapted to be held by the lifting fork of the truck in cantilever fashion with said one girder disposed under said fork and'said other,

frame secured transversely to and above said horizontal frame, an elongate tension member secured at its respective ends to the ends of said horizontal frame and secured intermediate its ends to the top of said bridge frame, a pair of fiat vertical frames secured respectively to opposite sides of said horizontal frame at the overhanging end thereof and depending therefrom, a. horizontal, generally elongate platform secured to the lower ends of said vertical frames and extending beneath said horizontal frame, a gangplank telescopically mounted beneath said platform and selectively extendable away from said vertical frames, and a ladder secured vertically between said horizontal frame and said platform.

4. A portable scaffold adapted to be carried by a lift truck, comprising a flat, horizontal, generally elongate frame including a pair of transverse girders, one of said girders being disposed at one end of said frame, the other girder being spaced from said one girder inwardly of said frame and in a plane slightly above said one girder, said frame being adapted to be held by the lifting fork of the truck in cantilever fashion with said one girder disposed under said fork and said other girder disposed over said fork, a vertical bridge frame secured transversely to and above said horizontal frame in substantially the same vertical plane as said other girder, an elongate tension member secured at its respective ends to the ends of said horizontal frame and secured intermediate its ends to the top of said bridge frame, a pair of flat vertical frames secured respectively to opposite sides of said horizontal frame at the overhanging end thereof and depending therefrom, a, horizontal, generally elongate platform secured to the lower ends of said vertical frames and extending beneath said horizontal frame, a gangplank telescopically mounted beneath said platform and selectively extendable away from said vertical frames, and a ladder secured vertically between said horizontal frame and said platform.

JOHN L. THOMPSON.

JOHN BIBB.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 466,890 Dean Jan. 12, 1892 1,268,607 Pettis June 4, 1918 1,427,453 Fleming Aug. 29, 1922 2,068,825 Stevenson Jan. 26, 1937 2,362,170 Swaisgood Nov. 7, 1944 FOREIGN PATENTS Number Country Date 9,147 Great Britain 1911 250,300 Switzerland June 1, 1948