US3666046A

US3666046A - Portable scaffold

Info

Publication number: US3666046A
Application number: US107764A
Authority: US
Inventors: Clarence A Meinecke Jr
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-01-19
Filing date: 1971-01-19
Publication date: 1972-05-30
Anticipated expiration: 1989-05-30

Abstract

Described herein is a portable, vertically adjustable, scaffold. This scaffold comprises a base, a telescoping mast hingeably attached thereto and a platform. The telescoping mast is raised by a hydraulic hoist and the mast is rotated about its lower end with a hydraulic hoist. As the telescoping mast is raised, a cable secured to the mast raises the platform assembly along the mast. Outriggers are provided to add stability to the scaffold.

Description

United States Patent Meinecke, Jr.

[451 May 30, 1972 PORTABLE SCAFF OLD Clarence A. Meinecke, Jr., 306 South Pinet, Jefferson. lowa Filed: Jan. 19, 1971 Appl. No.: 107,764

Inventor:

3,344,885 10/1967 Rasmussen 182/145 3,378,101 4/1968 Zeitler 3,493,079 2/1970 Dudschus ..182/63 3,576,233 4/1971 Thatcher 182/ 145 Primary Examiner-Reinaldo P. Machado Attorney-Henderson & Strom [5 7] ABSTRACT Described herein is a portable, vertically adjustable, scaffold. This scaffold comprises a base, a telescoping mast hingeably attached thereto and a platform. The telescoping mast is raised by a hydraulic hoist and the mast is rotated about its lower end with a hydraulic hoist. As the telescoping mast is raised, a cable secured to the mast raises the platform assembly along the mast. Outriggers are provided to add stability to the scaffold.

8 Claims, 9 Drawing Figures Patented May 30, 1972 2 Sheets-Sheet l I Patented May 30, 1972 3,666,046

2 Sheets-Sheet 2 :4: 6 Mmswmz Mm A390.

BACKGROUND OF THE INVENTION This invention relates to a portable, vertically adjustable, scafiold which can be readily mounted on a pickup truck.

Portable scaffolds can be used for a wide variety of purposes. They are essential in building construction, in maintenance of street lights, window washing, etc. For many years, inventors have searched for a truly portable scaffold. These attempts are documented in Wille, U.S. Pat. No. 3,367,448; Bergman, U.S. Pat. No. 3,l78,048; Wiegand, U.S. Pat. No. 3,003,584; Smith, U.S. Pat. No. 3,232,377; Aune, U.S. Pat. No. 2,423,167; and Dudscus, U.S. Pat. No. 3,493,079.

Although all of these scaffolds serve a useful purpose, they do not meet the requirements of simplicity, low cost, and ease of portability. The present invention provides a simple, economical, easily portable scaffold that can be mounted on a pickup truck or can be used by itself with a minimum of conversion time. The scaffold is readily mounted on or removed from a pickup truck.

SUMMARY OF THE INVENTION This invention relates to a portable, vertically adjustable scaffold comprising a base means, a telescoping mast having an inside and an outside elongated tube, the inside tube being rotatably attached at its lower end to the base means, the mast having a hydraulic means for raising the outside tube in sliding engagement with the inside tube. A second hydraulic means is provided for rotating the mast about the lower end of the inside tube. The platform is arranged for vertical guiding movement on the mast when the mast is in the vertical position and the platform is raised and lowered by means of cables secured to the mast and to the platform. When the outside tube is raised, the platform is also raised.

It is an object of this invention to provide a portable scaffold of novel construction which is economical to build and readily portable.

Another object is to provide a portable scaffold having a telescoping mast hingeably secured to the base.

A further object is to provide a portable scaffold which can readily be mounted on or removed from a pickup truck.

Yet another object is to provide a scaffold having a foldable mast which can be folded quickly and easily.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a pickup truck having the portable scaffold of this invention mounted thereon with the mast in folded position.

FIG. 2 is a side view of the portable scafiold of this invention mounted on a pickup truck with the mast in a raised position.

FIG. 3 is an enlarged side view of the portable scaffold of this invention illustrating, in phantom, the platform assembly in raised position.

FIG. 4 is a perspective view of the forward end of the portable scaffold with the top of the mast cut away.

FIG. 5 is a cross-sectional side view of the portable scafi'old taken along line 5-5 of FIG. 4 showing the locking arm in engagement with the mast.

FIG. 6 is a side view of the platform assembly in guiding engagement with the mast. Portions of the platform assembly are cut away to show the wheels which contact the mast and guide the platform. 1

FIG. 7 is a cross-sectional front view of the upper portion of the platform assembly taken along 7-7 of FIG. 6.

FIG. 8 is a top view of the platform assembly taken along line 8-8 of FIG. 6 and showing the mast in cross-section.

FIG. 9 is a schematic of the hydraulic system of the portable scaffold.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, the portable scafi'old of this invention is generally indicated at 11 in FIGS. 1-3. The portable scaffold 11 is comprised of a base means 12 (FIGS. 3-5 a telescoping mast 13 (FIG. 3) having an inside tube 14 and an outside tube 16 with a first hydraulic means 17 connected thereto. A second hydraulic means 18 is secured to the mast 13 for rotating the mast 13 about its lower end. A platform assembly 19 supported by cables 21 is arranged for vertical guiding movement on the outside tube 16 when the mast 13 is in a vertical position.

More specifically, the base means 12 (FIGS. 3-5) is preferably comprised of l-beams 22 disposed at right angles in the same horizontal plane and rigidly secured together. The lbeams 22 generally are arranged in rectangular configuration but many other configurations can be utilized. Preferably, the base means 12 is of such a size that it can readily be placed in a standard pickup truck 23 as illustrated in FIGS. 1 and 2.

Two angle members 24 and 26 (FIG. 4) are secured between opposite sides of the base means 12. The lower end 27 of the hydraulic cylinder 28 of the second hydraulic means 18 is rotatably supported by a pin 29 secured to cross

members

31 and 32 which in turn are secured to the

angle members

24 and 26.

Longitudinal struts 33 (FIGS. 3 and 4) are rigidly connected between the front I-beams 34 and the forwardmost angle member 24. A heavy duty hinge 36 is secured to the front I- beam 34 and, additionally, is secured to the longitudinal struts 33.

The mast 13 (FIG. 3) comprises an inside tube 14, an outside tube 16, and a first hydraulic cylinder 17. The inside tube 14 is hingeably secured to hinge 36 at its lower end 37 and is rotatable therearound. The inside tube 14 can be of any configuration in cross-section but, preferably, is square or rectangular. The length of the inside tube 14 is not critical but preferably is about the length of the box of an ordinary pickup truck. Depending on the particular use desired, the inside tube 14 can be either longer or shorter. On the forward side 38 of the inside tube 14, a bar 39 is horizontally disposed which mates with a latching arm 40 secured to the front I-beam 34. Proximate the lower end 37 of the inside tube 14 and on the rearward side 41, a lug 42 is formed for rotatably securing the upper end 43 of the hydraulic cylinder 38 thereto.

The outside tube 16 (FIG. 3) is of the same general configuration and length as the inside tube 14. The outside tube 16 should be slightly larger in inside diameter than the inside tube 14 is in outside diameter. Therefore, the outside tube 16 mates over the inside tube 14 and is slidingly engaged therewith. The outside tube 16 is hollow and open on both ends 44 and 46. At the upper end 46, two pulleys 47 are rotatably secured by axle 48 The first hydraulic means 17 (FIGS. 3 and 9) comprises an elongate hydraulic cylinder 49. The cylinder 49 is disposed within the inside tube 14 and is secured at its lower end 51 to the inside tube 14 proximate the lower end 37 of the inside tube 14. The upper end 52 of the cylinder 49 is secured to a plate 53 rigidly secured horizontally proximate the upper end 44 of the outside tube 16. The plate 53 is provided with apertures 54 through which cables 21 can pass. Hydraulic fluid is supplied to the cylinder 49 by a pump 56 through a two-way valve 57.

A latching arm 40 (FIGS. 3 and 4) is secured on the front beam 34 and is securable with bar 39. The latching arm 40 is rotatably secured on forwardly extending lug 58 mounted on the front I-beam 34. Mechanical linkage 59 (FIG. 4) is utilized to release and/or lock the latching arm 40 in engagement with bar 39. The latching arm 40 is matable with the bar 39 only when the mast 13 is in an upright or vertical position.

The second hydraulic means 18 (FIG. 3), as indicated previously, is a hydraulic cylinder 28 rotatably connected to the inside tube 14 of the mast l3 and to the base means 12 and is utilized to rotate the mast 13 about the lower end 37 of the inside tube 14 between an essentially horizontal position and a vertical position. The twoway valve 57 and the pump 56 supply hydraulic fluid to the cylinder 28 and control the flow of hydraulic fluid thereto.

The two-way valve 57 is mechanically connected to the latching arm 39 by arm 60 (FIG. When the mast 13 is in a vertical position and locked in position, hydraulic fluid flows only into the first hydraulic cylinder 49 and the fluid in the second hydraulic cylinder 28 is sealed therein thereby locking the second hydraulic cylinder 28. When the latching arm 39 is in the release position, hydraulic fluid flows only into the second hydraulic cylinder 28.

The platform assembly 19 (FIGS. 3 and 6) is arranged for vertical guiding movement along the outside tube 16. The platform assembly 19 comprises a deck 61 disposed rearwardly of the mast 13 when the mast 13 is in a vertical position. The deck 61 is generally of rectangular configuration. A series of lateral bars 62 and longitudinal bars 63 comprise the superstructure and these

bars

62 and 63 are covered with decking material 64. Guard rails 65 are dcmountably secured around the sides of the deck 61. Centering guides 66 are formed on the bottom 67 of the deck 61 and secure the platform assembly 19 from moving horizontally when the mast 13 is in its folded position.

Two vertical struts 68 and 69 (FIGS. 3, 6 and 8) of L- shaped configuration are secured to the forward edge 71 of the deck 61 and extend upwardly of the deck 61 on opposing sides of the mast 13.

A plurality of wheel means 73 or rollers are secured to the platform assembly 19 for guiding the platform assembly 19 vertically along the outside tube 16 of the mast 13. The rollers 73 are disposed on all four sides of the mast 13.

The forward roller 74 (FIGS. 6 and 7) is supported on an axle 76 joining the top and forwardmost portions 77 of the L- shaped

struts

68 and 69 and is in constant contact with the outside tube 16 when the mast 13 is in an upright position. Side rollers 78 are secured to the

struts

68 and 69 and rollingly engage the sides of the outside tube 16. The rear roller 79 is secured to the deck 61 and contacts the rearward side of the outside tube 16. The mast 13 can readily be folded into the horizontal position without disengaging or otherwise manipulating any of the rollers 73.

At least one cable 21, and preferably two cables 21, secure the platform assembly 19 to the mast 13 (FIG. 3). One end 81 of the cables 21 is secured to the deck 61 by means of side straps 72 on each side of the mast. The cables 21 extend upwardly and over the pulleys 47 secured to the top 46 of the outside tube 16. The cables 21 then extend downwardly through the outside tube 16, through the apertures 54 in plate 53 and are secured, at the other end 82, to the inside tube 14. As the outside tube 16 is raised, the platform assembly 19 is raised twice as far as the outside tube 16.

The hydraulic pump 56 is controlled from the platform assembly as shown in FIG. 2. An electrical line 83 secured on the platform assembly 19 is utilized to control the raising and lowering ofthe platform assembly 19.

Outrigger means 84 of novel construction are secured to the base means 12. The outrigger means 84 comprises arcuate, 90,

arms

86 and 87 extending outwardly of opposite sides of the portable scaffold 11. The

arms

86 and 87 are slidingly engaged with the base means 12 by clamp means 88.

Each of the clamp means 88 (FIG. 4) is comprised of the flat, widened end 89 of the

arm

86 and 87, a spacer 91 and a bottom widened member 92. The clamp means 88 is secured together by nuts and bolts 93. The nuts and bolts 93 can be loosened to render the clamp means 88 in sliding engagement with the front I-beam 34.

The other end 94 (FIG. 4) of the

arms

86 and 87 is comprised of an attachment cylinder 96. Two holes are formed through the attachment cylinder 96 to secure the jack extensions 97 in either a vertical position or in a horizontal position.

The jack extensions 97 (FIG. 4) are similar to those jacks used on pickup campers. The foot 98 may be turned down or up manually or electrically and is capable of reaching the ground and stabilizing the scaffold 11. A hollow attachment cylinder 99 is formed on the jack extensions 97 and mates with the first attachment cylinder 96.

If it is desired to use the scaffold 11 without the truck 23, the

arms

86 and 87 can be secured to the bottom portion 10 of the I-beams 22 and wheels (not shown) can be secured to the first attachment cylinder 96.

The outrigger means 84 can be utilized to load and unload the scaffold from the truck 23. A third outrigger (not shown) can simply be attached to the mast 13 in folded position or to the rear of the base means 12. The scaffold 11 can then be easily raised and/or lowered.

In a second embodiment of this invention, two masts 13 can be utilized, one on each end of the base means 12. The operation of the scaffold 11 is exactly the same except the rearward mast 13 folds forwardly rather than rearwardly. By using this construction, heavier loads can be raised and lowered.

Although a preferred embodiment has been described, it is to be remembered that various modifications may be made without departing from the invention as defined in the appended claims.

I claim:

1. A portable, vertically adjustable, scaffold comprising:

base means;

a telescoping mast having an inside, elongated tube hingeably attached at the lower end thereof to said base means and rotatable about said lower end from an essentially horizontal position to a vertical position; an outside, elongated tube mating over said inside tube and slidingly engaged with said inside tube; and first hydraulic means secured to said inside tube and connected to said outside tube for raising said outside tube relative to said inside tube;

second hydraulic means for rotating said mast about said lower end ofsaid inside tube;

a platform assembly arranged for vertical guiding movement along said outside tube when said mast is in a vertical position;

at least one cable having two ends, one of said ends being secured to said platform and the other of said ends being secured to said mast so that said platform is raised when said outside tube is raised; and

outrigger means adjustably secured to said base means for adding stability to said vertically adjustable scaffold.

2. The portable scaffold of claim 1 wherein said first hydraulic means is disposed inside said inside tube.

3. The portable scaffold of claim 1 wherein a locking arm is rotatably secured to said base means, said locking arm secu rable to said mast when said mast is in an upright position.

4. The portable scaffold of claim 3 wherein a two-way valve controls the flow of hydraulic fluid into said first hydraulic means and said second hydraulic means, said two'way valve being mechanically connected to said locking arm and allowing hydraulic fluid to flow into said first hydraulic means only when said locking arm is secured to said mast and allowing hydraulic fluid to flow into said second hydraulic means only when said locking arm is not secured to said mast.

5. The portable scaffold of claim 4 wherein said platform assembly comprises:

a platform deck disposed rearwardly of said mast when said mast is in a vertical position;

two vertical struts of inverted L-shaped configuration secured to said deck on opposite sides of said mast;

a plurality of wheel means secured to said deck and said struts for guiding said platform deck vertically along said outside tube of said mast.

6. The portable scaffold of claim 5 wherein at least one pulley is secured proximate the upper end of said outside tube;

one end of said cable is secured to the platform deck by side strap means, and said other end of said cable is secured proximate the upper end of said inside tube, said cable passing upwardly through said outside tube and around said pulley to said side strap means. 7. The portable scaffold of claim 6 wherein said base means comprises l-beams disposed at right angles and rigidly secured together.

8. The portable scaffold of claim 7 wherein said outrigger means comprises:

arcuate arms slidably secured on opposite sides of said

Claims

1. A portable, vertically adjustable, scaffold comprising: base means; a telescoping mast having an inside, elongated tube hingeably attached at the lower end thereof to said base means and rotatable about said lower end from an essentially horizontal position to a vertical position; an outside, elongated tube mating over said inside tube and slidingly engaged with said inside tube; and first hydraulic means secured to said inside tube and connected to said outside tube for raising said outside tube relative to said inside tube; second hydraulic means for rotating said mast about said lower end of said inside tube; a platform assembly arranged for vertical guiding movement along said outside tube when said mast is in a vertical position; at least one cable having two ends, one of said ends being secured to said platform and the other of said ends being secured to said mast so that said platform is raised when said outside tube is raised; and outrigger means adjustably secured to said base means for adding stability to said vertically adjustable scaffold.

3. The portable scaffold of claim 1 wherein a locking arm is rotatably secured to said base means, said locking arm securable to said mast when said mast is in an upright position.

4. The portable scaffold of claim 3 wherein a two-way valve controls the flow of hydraulic fluid into said first hydraulic means and said second hydraulic means, said two-way valve being mechanically connected to said locking arm and allowing hydraulic fluid to flow into said first hydraulic means only when said locking arm is secured to said mast and allowing hydraulic fluid to flow into said second hydraUlic means only when said locking arm is not secured to said mast.

5. The portable scaffold of claim 4 wherein said platform assembly comprises: a platform deck disposed rearwardly of said mast when said mast is in a vertical position; two vertical struts of inverted L-shaped configuration secured to said deck on opposite sides of said mast; a plurality of wheel means secured to said deck and said struts for guiding said platform deck vertically along said outside tube of said mast.

6. The portable scaffold of claim 5 wherein at least one pulley is secured proximate the upper end of said outside tube; one end of said cable is secured to the platform deck by side strap means, and said other end of said cable is secured proximate the upper end of said inside tube, said cable passing upwardly through said outside tube and around said pulley to said side strap means.

7. The portable scaffold of claim 6 wherein said base means comprises I-beams disposed at right angles and rigidly secured together.

8. The portable scaffold of claim 7 wherein said outrigger means comprises: arcuate arms slidably secured on opposite sides of said portable scaffold and extending outwardly thereof, each of the outer ends of said arcuate arms terminating in an attachment cylinder; jack extensions secured on said attachment cylinders and rotatable thereon; said jack extensions capable of reaching the ground when said portable scaffold is mounted on a truck.