WO2004040082A1

WO2004040082A1 - Drywall panel carrier

Info

Publication number: WO2004040082A1
Application number: PCT/US2002/034527
Authority: WO
Inventors: Charles Ray; David Peterson
Original assignee: Charles Ray; David Peterson
Priority date: 2002-10-25
Filing date: 2002-10-25
Publication date: 2004-05-13
Also published as: CA2503758C; CA2503758A1; AU2002350022A1

Abstract

Apparatus for lifting and transporting panels on a lift platform has a pair of panel-supporting legs (100) of square metal tubing attachable to side rails (14, 20) of the lift platform. Each of the legs is connected to the rails by an upper bracket (116) at the top (102) of the leg and a lower bracket (156) at a middle location. A panel-receiving U-shaped channel (124) is located on the opposite side of the leg, away from the rails. The lower bracket has a standoff member (162) included in its connection to the leg, projecting the bottom of the leg outward at an angle. A roller (136) at the base of the channel provides low-friction rolling contact with an inserted panel, and a groove (142) in this roller serves to guide the panel. Rollers (118) at the top of the legs and elsewhere are placed to keep panels from being damaged by contact with the legs.

Description

DRYWALL PANEL CARRIER CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in part of Application Serial No. 09/842,584, filed 04/25/2001 by one of the present applicants.

FIELD OF THE INVENTION

This invention relates to handling of building panels at construction sites and more particularly to equipment for transporting and lifting of panels to an elevated position convenient for installers.

BACKGROUND OF THE INVENTION

Handling of building panels such as drywall or "Sheetrock" panels has presented difficulties, especially for large panels being installed in commercial buildings at heights above a first floor level. Drywall panels for such applications may be as large as four feet by twelve feet and weigh one hundred pounds or more. It is readily apparent that any improvement in equipment and procedures for lifting such panels to a required elevated location would be welcomed by installers.

Use of scissors-type lift machines has become a common practice at commercial building sites. These devices have sets of paired extendable arms mounted on a wheeled and powered chassis and a work platform supported by the arms. For safety reasons the platforms have horizontal rails around their outer edges supported by upright posts. The rail structure generally includes an upper rail some three feet above the platform floor and a lower rail halfway between the floor and the upper rail. The rails generally take the form of square or round metal tubing. Lift platforms of this type may be eight feet by three feet or larger in size and provide space for two to three workmen. Such machines are exemplified by U. S. Patent No. 6, 158,550, issued December 12, 2000 to Arnoldy, which patent is hereby expressly incorporated by reference.

Attempts have been made to use existing lift machines for lifting large panels along with the workmen to an elevated working level, with the panel being supported by measures such as placing the panel on edge on a workman's foot extending outside of the platform at each end. This approach is dangerous and difficult to maintain for the period of time required to move the machine from a stack of panels to a desired final location. Other approaches such as placing the panel on top of the platform rail are not effective for large panels owing to a lack of space, and may result in damaging the panel when it comes into contact with metal surfaces or corners.

Desirable features for a panel- supporting device include a bottom channel adapted to allow a panel to be slid on edge into a transporting position under conditions avoiding exposure of the panel to scraping or tearing, a means to restrain the panel from sliding out during transport and a means to facilitate movement of the panel when lifted by workmen off the device and into position for installation.

SUMMARY OF THE INVENTION The present invention is directed to apparatus for lifting and transporting panels of material such as drywall to a desired location at a construction site. The apparatus comprises a pair of panel-receiving legs attachable to side rails of a lift platform, with the legs when attached extending generally in a vertical direction. Square metal tubing is a suitable material for making the legs.

Each of the legs has a top, bottom and midpoint along its length, an inside surface facing the platform when installed and an outside surface facing the opposite direction. Means are provided for removably connecting the tops of the legs to the upper rail and midpoints to the lower rail of a lift platform. Clamps connected to the rails and having opposing jaws engaging the rails or u-shaped brackets secured by pins may be used.

The legs each have a panel-receiving channel at the bottom of the leg and on the outside thereof, with a low-friction contact member at the base of the channel to obtain enhanced rolling or sliding movement of the panels. The contact member may comprise a material such as a plastic having a slick, low-friction surface or a roller. A preferred structure is to use a spool- shaped roller having lips on its ends, defining a groove between the lips of sufficient width to receive the thickness of the panel and guide it along, preventing the panel edge from coming in contact with metal components of the leg. This protects the panel edge area from being scratched or damaged.

Low friction contact surfaces may also be provided at various other locations so as to keep the panels from being slid over surfaces which would present higher friction. This feature may be implemented in the form of rollers placed to guide panel faces as well as edges from coming into contact with other structural components of the legs.

An additional roller may be provided at the top of the leg mounted on an axis parallel to the platform rail. This roller is placed to keep the panel from coming into contact with other structures of the top of the leg when the panel is lifted up for movement to a position required for installation. In addition this roller serves as a pivot point around which the panel is manipulated and guided by the workmen.

To provide for easier handling of panels and to keep them from tipping outward at the top while being moved the bottoms of the legs may be positioned outward from the platform floor while the tops are held close to the top rail, causing the panel to be tilted slightly inward at the top. This result may be obtained by mounting the lower clamp on a standoff member of a suitable length whereby the leg is projected outward at the bottom. Inclining the leg at an angle of ten to fifteen degrees is preferred.

Variations in distance between upper and lower rails of different platform lifts may be accommodated by mounting the lower clamp on a sleeve which fits over the leg and is free to move upward and downward within limits.

Another feature of the invention is to provide an adaptation for use in lifting narrower panels having a width such as two to three feet. The panel- receiving structure may be mounted with bolts and wing nuts at the bottom end of the leg or at an alternative location upward from the bottom. The upper location enables the upper edge of narrower panels to reach the level of the upper roller when placed in position to be lifted.

The invention also may include a braking mechanism for the rollers at the base of the channels of the legs in order to prevent unintended rolling or sliding when the platform stops or starts. This may be provided in the form of a lock pin insertable in openings in the rollers or a friction brake. Apparatus embodying the invention provides important advantages, particularly in the ease and convenience of moving large and heavy panels to a position which is optimum for further movement to a final location for installation. Safety and productivity are thereby enhanced, and damage to panels is reduced.

It is accordingly an object of this invention to provide a panel-carrying attachment for lift platforms.

Another object is to provide a panel-carrying attachment having low friction, load-bearing surfaces enabling ease of handling panels.

Yet another object is to provide a panel-carrying attachment which includes means for protecting panels from being damaged.

Other objects and advantages of the invention will be apparent from the following detailed description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view of a panel-supporting leg embodying the invention.

Fig. 2 is an elevational view thereof taken from a side.

Fig. 3 is an elevational view taken from outside the leg when installed.

Fig. 4 is a perspective view of a panel-receiving assembly removably attachable for use with narrow panels.

Fig 5 is a perspective view showing a pair of legs installed on rails of a lift platform, with a drywall panel shown in dashed lines.

Fig. 6 is a perspective view of an embodiment of the invention using a grooved roller at the base of the panel-receiving channel.

Fig. 7 is an enlarged view of a panel-receiving assembly of Fig. 6. Fig. 8 is a sectional view of the bottom roller of Fig. 6.

Fig. 9 is a sectional view of an alternate roller.

Fig. 10 is a fragmentary view showing use of a plastic bumper to protect panels from damage.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to Fig. 6 of the drawings there is shown a panel- supporting leg 100 which is a component of a panel-lifting and carrying apparatus embodying the invention. Two such legs are required at spaced-apart locations along the length of a lift platform for effective support of panels. Leg 100 preferably takes the form of a square metal tube which may have a width of one inch and a length of three feet. The leg has a top end 102, a bottom end 104 and a middle area 106 between the ends. Flat side 108 of the leg is positioned on the inside of the tube when connected to upper horizontal rail 14 and lower rail 20 of the lift platform (Fig. 5), and flat side 110 is positioned away from the rails.

An upper plate 114 is connected across top end 102 of the leg, providing support for a U-shaped bracket 116 defined in the inner end of the plate and for a roller 118 mounted on tabs 120 connected to the plate. Bracket 116 is adapted to be hooked over the upper rail and secured by set screw or L-bolt 122. Roller 118 is placed so that its outer circumference 117 extends past edge 112 of plate 114 at its juncture with top end 102 at flat side 110, thus keeping the carried panel spaced outward from metal components at the top of the leg. Rollers 118 also provide convenient pivot points guiding movement of the panel during an initial step of unloading at an installation site. A panel- receiving channel 124 is provided adjacent the lower end of the leg or at an alternate, higher location when adjustment is made for narrower panels. Components which form the channel in combination with the leg may be provided in the form of an assembly 126 adapted to be bolted on at the selected location. In the embodiment shown in Fig. 6 assembly 126 includes a U-shaped bracketl28 conforming to the shape of the leg, a base plate 130, a vertical side plate 132 and a horizontal guide plate 134 parallel to the bracket base.

A roller 136 is mounted above base plate 130 on an axis perpendicular to flat side 110 of the leg. The roller has lips 138, 140 at each end, defining a groove 142 in which edge portions of panels pay be placed, These rollers support the weight of the panel as it is being slid into position and result in less effort being required for loading. The grooves serve to keep edges of the panel bearing down on the rollers from sliding over and coming into contact with metal framework owing to tilting of the panels, which is carried out in order to obtain an optimum orientation for unloading.

The assembly 126 may also include a pair of rollers 144, 146 mounted on bracket 128 on axes parallel to the leg and having their circumferences spaced into the channel so as to keep faces of the panel from coming into contact with the leg. A similar pair of rollers 148, 150 may be mounted on the leg at a middle point of the leg, these rollers serving the same purpose as rollers 144, 146 and being oriented in the same direction.

Assembly 126 also includes a braking mechanism for locking roller 136 in place once a panel is loaded so as to prevent panels from sliding off when movement of the lift platform is started or stopped. A locking pin 152 carried in plate 132 may be inserted in a selected aperture 154 in roller 136 to restrain the roller from rotating.

Assembly 126 may be secured in place at the bottom of the leg by bolts or pins 135, 137 extending through apertures in the bracket and the leg (not shown). Alternate apertures 139 and 141 are provided at a location one foot higher on the leg, Additional apertures at other locations may also be used.

A bracket 156 is provided at a middle location on the leg for connecting it to the lower rail of the lift platform. This bracket has a U-shaped structure with an opening on a side away from the leg, the bottom plate 158 of the bracket carrying a screw 160 which may be used to close the opening when the bracket is in place over the rail. The bracket is carried on a standoff arm.162 which in turn is connected to a sleeve 164. The sleeve fits loosely over the leg so as to allow the bracket to be moved to different levels for use on lift platforms having this rail located at varying levels.

Standfoff arm 162 is used to impart a slight tilt to the leg, resulting in the panel being inclined outward at the bottom. This stabilizes the panel during movement of the lift platform and facilitates performance of an initial step wherein workmen unloading the panel are required to lift the panel over their heads. The standoff arm may preferably have a length sufficient to incline the leg at an angle of ten to fifteen degrees away from vertical.

Fig. 8 shows details of roller 136, which is located at the base of assembly 126 in Fig. 7. The roller has lips 138 and 140 at opposite sides, defining a groove 142 with a flat bottom between the lips. Groove 142 has a width sufficient to receive an edge portion of a panel and guide it along as the panel is moved into position. This measure serves to prevent damage to bottom edges of panels, which might otherwise occur due to a tendency of a tilted panel to slide over and come into contact with metal components of the assembly. Fig. 9 shows another embodiment alternative to the roller shown in Fig. 8. In this embodiment roller 166 has a concave arcuate groove at its center disposed between side end portions 168 and 170.

Fig, 10 shows an embodiment where bumpers 174 and 176 are applied to outside surface 110 of the leg at positions where the panel might come into contact with metal surfaces or corners of the leg. The bumpers are preferably semicircular in shape and may be made of high molecular weight plastic, which is a commercially available product characterized by having a low-friction surface. This measure may be used as an alternative to providing rollers at all locations except at the base of the panel-receiving channel and at the top of the leg.

In order to prevent overloading of the panel lifting apparatus, as might occur if too many heavy panels were placed on the legs at one time, the width of panel-receiving channel 124 is preferably limited to a distance between rollers 144 and 146 and guides 134 of about one to one and one- half inch. This would allow room for only panel, with enough slack provided to enable free movement. Also, after one panel is loaded on the supporting legs, it would be difficult to load a second one because rotation of the rollers when the second panel is being slid into position would cause the first panel to be moved outward. The width of groove 142 in roller 136 further limits loading to a single panel of drywall material. In operation of of the apparatus of this invention for installing wall panels, it is preferred to bring the lift platform, when loaded, into a position such that the legs and supported panels are located on a side rail away from the wall on the panels are being installed. This allows the opposite side of the platform to be brought closer to the wall and minimizes the distance over which the installers would need to reach. Removal of the panel from the legs and into position on the wall also proceeds more smoothly than if the legs were on a side adjacent to the wall.

By reducing the amount of manual physical effort required on the part of workmen in lifting and transporting drywall panels, use of the invention may allow a reduction in the number of workmen needed for a crew performing this work. Under typical conditions, only two men would be needed instead of three as previously required for operation of a lift platform in installing large drywall panels.

Figs. 1 to 5 are directed to embodiments of the invention wherein certain features of the embodiments of Figs. 6 to 10 are lacking, in particular use of a grooved roller at the base of the panel-receiving assembly.

Although the invention is described with reference to drywall panels, it is to be understood that the panels may be comprised of other materials such as plywood and other wood-based compositions as well as polymeric materials such as polycarbonates and glass.

The posts for panel- supporting legs preferably may be metal tubes having a rectangular or square cross-section, but the invention includes posts in the form of shapes such as angle iron, circular pipes, beams or the like.

It is also to be understood that although the invention is described above in terms of specific embodiments, it is not so limited, but is limited only as defined in the appended claims.

Claims

1. Apparatus for supporting sheet material panels on a lift platform having a floor and a plurality of spaced-apart horizontal rails disposed around a periphery of said floor and above said floor, said apparatus comprising: a pair of panel-supporting legs attachable to said rails, each said leg comprising a rigid post having a top end, a bottom end, a middle portion, a first side facing a said rail when installed and a second side facing away from said rail when installed; each said leg at said top end having attached thereto an upper rail- engaging member located on said first side and adapted for being connected to an upper one of said rails; each said leg also having attached thereto at a said middle portion thereof a a lower rail-engaging member located on said first side and adapted for being connected to a lower one of said rails; each said leg at a lower portion thereof having support members embers defining a panel-receiving channel on said second side facing away from said rails, said support members including a roller mounted on an axis perpendicular to said leg at said second side and providing a rotating base upon which a panel may be placed, said roller having a lip at each end thereof, defining therebetween a groove in which a said panel may be placed on edge and supported for movement in a direction parallel to said rails.

2. Apparatus as defined in claim 1 wherein said rail-engaging member comprises a plate having a proximate end joined to said top end of said leg and a distal end including a first bracket adapted to be hooked over a said rail and removably connected thereto.

3. Apparatus as defined in claim 2 including a second roller mounted on said plate on an axis parallel to said rails and having its circumference located outwardly past said second side of said leg whereby a panel in contact with said second roller will be kept spaced apart from said leg.

4. Apparatus as defined in claim 2 wherein said lower rail-engaging member comprises a second bracket connected to said middle portion and positioned in spaced-aparlt relation to said leg.

5. Apparatus as defined in claim 4 including a standoff arm disposed between said leg and said second bracket whereby said leg may be placed in position so as to be tilted toward the rails at the upper end of the leg when installed.

6. Apparatus as defined in claim 5 including a sleeve slidably disposed over said leg and connected to a proximate end of said standoff arm whereby said second bracket may be moved to variable vertical positions.

7. Apparatus as defined in claim 6 including a first pair of rollers mounted on said leg at a middle location thereof, each roller of said pair placed across from on another and on an axis parallel to said leg and each said roller of said pair having a circumference extending outwardly past said second side of said leg, whereby contact of a supported panel with said second side will be prevented and movement of a panel in a longitudinal direction will be facilitated.

8. Apparatus as defined in claim7 further comprising a second pair of rollers mounted on said leg adjacent said panel-receiving channel , each roller of said second pair placed across from one another on an axis parallel to said leg, and each roller of said second pair having a circumference extending outwardly past said second side of said leg whereby contact of a supported panel with said second side will be prevented.

9. Apparatus as defined in claim 1 including a bumper made of low friction plastic material dispased along a vertically extending portion of said second side of said legs.

10. Apparatus as defined in claim 1 wherein said support members defining a panel-receiving channel comprise an assembly removably attachable to said leg at a selected one of a plurality of vertically spaced apart locations on said leg .