A foldable wheeled stand is provided for supporting a motor driven pipe threading machine during operation thereof, for transporting the machine from one location to another, and for storing the machine during periods of non-use. The stand includes an upper support portion on which the machine is mounted, and a scissors-type foldable leg assembly providing a lower support portion by which the upper support portion and threading machine can be elevated and lowered relative to an underlying support surface. Elevating and lowering is achieved through a crank actuated jackscrew arrangement. The lower support portion includes a pair of wheels, whereby the stand, when folded, can be pivoted relative to the wheels to an inclined angle at which the stand and the threading machine mounted thereon are supported by the wheels for movement along the underlying surface. Further, the lower support portion includes a pair of skids which, when the stand is folded, facilitate sliding of the stand and the reading machine mounted thereon upwardly or downwardly relative to a fixed edge or edges above the underlying surface such as would be defined for example by stairs, or the edge of the bed of a truck relative to which the stand and machine are to be loaded or unloaded.
Paul W. Gress, John H. Jansen
Original Assignee: Emerson Electric Co.
BACKGROUND OF THE INVENTION
This invention relates to the art of stands for metalworking machine and, more particularly, to foldable a stand for a power driven threading machine.
The use of portable power driven pipe and rod threading machines to facilitate the on site preparation of threaded pipe and rod is of course well known, and it is likewise well known to provide a stand to support such a machine during metalworking operations. Certain such stands heretofore provided have included four ground or floor engaging legs while others have included a pair of such legs and a pair of wheels which facilitate lifting one end of the stand for the stand and the machine mounted thereon to be supported by the wheels for movement from one location to another along an underlying support surface such as a floor or ground.
While stands of the foregoing character adequately serve to support the threading machine during operation thereof and provide a degree of portability with respect to the machine, a number of problems are encountered in connection with both the portability and transportability of the machine and stand. In this respect, the loading or unloading of the stand and machine thereon relative to the bed of a truck, a loading dock or the like, may require the use of a forklift truck, an elongated ramp if the stand is wheeled, and/or the physical efforts of at least two workmen, especially in connection with physically lifting or lowering the stand and machine relative to a truck bed or dock. In connection with wheeling the stand and machine up or down a ramp, or physically lifting or lowering the stand and machine, it will be appreciated that the vast majority of the weight of the stand and machine is that of the machine alone, which may for example be 150 to 200 pounds, and that the center of gravity of the stand and machine is therefore relatively high with respect to the underlying support surface, therefore, extreme care must be taken to avoid tipping of the stand and machine during such movement thereof, adding to the physical exertion on the part of the workmen in connection with such loading or unloading operations. Furthermore, if it is necessary to move the stand and machine up or down a stairway to or from a location of use, storage or like, the tipping and physical exertion problems are multiplied. Further in connection with moving the stand and machine up or down a stairway, the wheels of wheeled stands heretofore provided interfere with such movement and add to the difficulty and physical exertion required in connection therewith by engaging against the stair riser in moving up the stairs and by having to drop along the riser between adjacent steps in going down the stairs. Accordingly, it will be appreciated that the transportation of such stands with threading machines mounted thereon is time consuming, physically tiring, and can be extremely hazardous for the workmen and potentially damaging to the machine should tipping occur.
It has been proposed to provide a foldable stand for threading machines comprised of a scissors-like leg assembly having ground engaging wheel and handle components and which is spring loaded to be moved from the folded to the extended position with the metalworking machine mounted thereon. When folded, the wheels and handle facilitate elevating one end of the stand and machine relative to ground for the stand and machine to be supported by the wheels for movement from one location to another. However, the spring force required to facilitate displacement of the stand and machine to the extended position and to maintain the latter position is such that the folding and extending operations are hazardous to a workman and can lead to injury. Furthermore, while the collapsing does lower the center of gravity of the machine so as to reduce the problem of tipping in connection with transportation of the stand and machine, the loading or unloading of the stand and machine relative to a truck bed or movement of the stand and machine up or down a stairway remains time consuming and physically demanding on the part of the workmen performing these tasks. The latter is due at least in part to the interference of the wheels of the stand with such movement thereof as described above.
Another problem encountered in connection with pipe threading machine stands heretofore provided is the susceptibility thereof to tilting about an axis transverse to the machine axis under certain work loading conditions. In this respect, such machines are capable of threading one end of an elongated pipe or rod which can extend a considerable distance beyond the end of the machine opposite the end at which threading takes place. Accordingly, if the length of the workpiece extending from the machine is too long, the weight thereof, unless separately supported, will tilt the machine relative to the underlying surface. Therefore, either a separate workpiece supporting stand is required to preclude such tilting, or operation of the machine must be limited to predetermined lengths of workpieces. Even in connection with the latter, it will be appreciated that if the workman accidentally tries to thread a workpiece which is too long, the stand and machine may tilt in the foregoing manner. Any such tilting endangers the workman and is potentially damaging to the machine.
Yet another problem encountered in connection with such stands heretofore provided is that storage of the stand and machine mounted thereon consumes considerable floor space. Even if the stand is foldable, the latter and the machine mounted thereon are in a horizontal disposition when stored and, thus, require a floor area for storage at least equal to the area of the stand and machine during use. In connection with a foldable stand, the latter may require a greater floor area for storage when folded than than unfolded. Still a further disadvantage results from the fact that the threading machine has but one working position which is at a fixed elevation relative to ground, whereby operation of the machine may be uncomfortable or awkward for many workmen.
SUMMARY OF THE INVENTION
In accordance with the present invention, an improved foldable stand is provided for power driven threading machines which provides the advantage of lowering the center of gravity of the stand and a machine mounted thereon to facilitate the portability thereof without tilting and which further provides for the loading and unloading thereof relative to a truck bed, the elevating or lowering thereof relative to an elevated edge fixed relative to ground, such as the edge of a loading platform or the like, and/or the movement of the stand and machine up or down a stairway to be facilitated in a manner which minimizes physical effort on the part of a workman or workmen, the time required to achieve such movement of the stand and machine, and the exposure of such workman or workmen to hazardous conditions. Preferably, these attributes are achieved through a foldable stand having a first or upper support portion on which the machine is mounted and a second or lower support portion which is foldable relative to the upper support portion so as to elevate and lower the upper support portion relative to an underlying support surface, and the provision of the lower support portion with wheel, skid and handle components interrelated to facilitate portability and transportability when the stand is in its folded disposition. In this respect, the handle can be grasped to elevate the folded stand and machine to an inclined disposition in which the wheels engage the underlying surface to facilitate movement of the stand and machine therealong, and the skids extend in the direction between the wheels and handle and facilitate sliding displacement of the stand and machine relative to the edge of a truck bed or loading platform, or along stairs, so as to facilitate loading, unloading and/or other sliding displacements of the stand and machine which may be desired or necessary. Preferably, the wheels and skids are relatively dimensioned and/or positioned for the outer surfaces of the wheels to be slightly spaced from the plane of the skids so that such sliding movements of the stand and machine are achieved without interference between the wheels and the edge or edges along which the skids are moved.
In accordance with another aspect of the invention, relative displacement between the upper and lower support portions by which the machine is elevated and lowered relative to the underlying support surface is achieved positively, safely and in a manner which enables adjusting the elevation of the machine relative to the underlying surface. The latter enables providing a working position for the machine which is most comfortable for a workman operating the same. Preferably, such positive elevating and lowering and thus selective positioning of the machine is achieved by interconnecting the upper and lower support portions through a jackscrew arrangement suitably actuated by the workman such as through the use of a crank.
In accordance with yet another aspect of the invention, the lower support portion of the stand is provided with an anti-tipping and storage arrangement. The component parts which provide the latter are positionally related relative to the wheels of the stand so as to restrain tipping of the machine and stand about the wheel axis during use of the machine and so as to cooperate with the wheels when the stand is folded to engage the underlying support surface to facilitate storage of the stand and machine in an inclined disposition relative to the underlying surface.
It is accordingly an outstanding object of the present invention to provide an improved foldable stand to facilitate the support and portability of a power driven threading machine mounted on the stand.
Another object is the provision of a foldable stand of the foregoing character having wheels and skids which, when the stand is folded, respectively support the stand and machine for wheeled movement relative to an underlying surface and for sliding movement relative to an edge or edges which are elevated with respect to an underlying surface.
Yet another object is the provision of a foldable stand of the foregoing character which provides for adjusting the height or use position of the machine relative to an underlying support surface when the stand is unfolded.
Still another object is the provision of a foldable stand of the foregoing character which, when unfolded to support the machine in a use position, is adapted to restrain tilting of the stand and machine about the wheel axis during a metalworking operation.
Still a further object is the provision of a foldable stand of the foregoing character which, when folded, provides for storage of the stand and machine in an inclined disposition relative to an underlying support surface.
Yet a further object is the provision of a foldable stand of the foregoing character which optimizes portability and transportability of a power driven threading machine mounted thereon, optimizes the time and physical effort required on the part of an operator or workman in connection with performing unfolding, folding, transportation and storage functions in connection with the stand and machine mounted thereon and optimizes safety with respect to the workman in connection with such functions.
Still another object is the provision of a foldable stand of the foregoing character which, with the machine mounted thereon, is easy to manually manipulate between the folded and unfolded positions thereof, is efficient in connection with its use to support a threading machine during operation thereof, and is easy and efficient to use in connection with the transportation and storage of the machine thereon during periods of non-use.