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[0001] 1. Field of the Invention
[0002] The present invention relates to hand trucks, dollies, and other land vehicles. More particularly, the present invention relates to lightweight, telescoping foldable and convertible hand trucks and/or platform carts which are used for transporting objects.
[0003] 1. Description of Related Art
[0004] Many improvements have been made in the area of hand trucks and dollies for material handling. However, none of these improvements have efficiently and effectively addressed the needs of professional musicians. Professional musicians are required to transport wide varieties of musical instruments and related gear often utilizing small cars and trucks over various terrains and changing environments while travelling to and from performance sites. Due to the virtual explosion in technology over the last ten years regarding P.A. systems, electronic keyboards, effects and the like, musical groups require more equipment than ever before. The problems of transporting the above-mentioned equipment have become increasingly difficult. It is desirable to create a specialized dolly or cart that can satisfy the criteria of musicians.
[0005] In the past few years, mini-vans and small trucks have been placed in common use for the transport of musical and other equipment. As such, space limitations have become of great concern to musicians. Any transport carts must now have a size which can carry large loads yet collapse to a small storage size so as to leave maximum room for equipment with the mini-van. Space is at a premium within a mini-van or a small truck.
[0006] Initially, it is desirable to produce a lightweight cart weighing under thirty-five pounds. It has been found that professional musicians experience finger stiffening and muscle stiffening in the hands and forearms when lifting objects over forty pounds which is deleterious to musical performance. In addition, the carrying of heavy equipment can contribute to back problems and related physical impairment. In addition, it also tights laryngeal muscles and, thus, hampers singing performance.
[0007] When transporting musical equipment, any cart or dolly should be capable of supporting at least five hundred pounds or more. Musical equipment is delicate and should be transported smoothly and without shock. In addition, the musical equipment should be properly supported and handled with care. Any handtruck or dolly must be able to reduce to a size of three feet of length or less with one side flat so as to facilitate receipt in small cars or trucks and/or baggage handling in airports.
[0008] In order to effectively accommodate keyboards and large P.A. cabinets, a cart must have the ability to extend to approximately fifty-four inches. It should also be short enough to maneuver through labrinyth-like corridors and elevators, often found in hotels and stage areas. Support should be provided on each end of the cart so as to maintain the expensive and delicate equipment within the confines of the frame of the dolly. Tall foldable sides can be useful for securing equipment such as drums, guitars, horns and the like, as well as acting as a hanger for various stage clothes. Also, the cart should be able to act as a “platform cart” so that the bed of the cart is flat with one side upright so as to accommodate long 24-channel mixing consoles or lighting trusses that would overhang the ends of the cart.
[0009] Since the equipment must be transported over various terrains, the cart should have the quality suitable for rolling smoothly, shock-free and quietly over such various terrains. The wheeled mechanism of the dolly or cart should be suitable for traversing curbs, stairs, grass, dirt and rough pavement. The cart should provide a broad frame surface so as to easily receive the equipment. A non-skid surface is useful in order to prevent odd-shaped instruments and widely-used polyethylene cases (which are notoriously slippery) from slipping and falling off during transport. The cart should be able to be converted from a two-wheel hand truck to a four-wheel cart or any other configuration both extremely quickly and efficiently. Since the cart must be loaded and unloaded often between musical performances, complete assembly into any loading configuration should be completed within ten seconds.
[0010] It is often the requirement of musicians that they must set up extremely quickly and must break down the equipment quickly. As such, it is a requirement for a musical instrument transport cart that the cart be able to be assembled into its proper position for receiving equipment very quickly and easily. Undue manipulation of screws, nuts, bolts, and other items wastes a great deal of time and is generally unsuitable for the purposes of the musician. A musical instrument transport cart must be capable of rapid assembly. The cart should also be capable of assuming any configurations within ten seconds or less. The cart should also be able to carry small objects on the frame without falling through.
[0011] It is also important for musical equipment to be maintained on a surface parallel to the surface on which the cart is travelling. As such, the frame of the cart should be supported on wheels which maintain the frame in parallel relationship to the earth. Any angling of the frame will tend to cause the equipment to move to the lowest end of the cart. The angling may also cause excessive and unexpected pressures to be applied to cart components. In order to enhance the ability to maintain the parallelism of the cart to the surface, the handle should be foldable in such a way so as to maintain this parallelism.
[0012] Various patents have issued in the past which deal with various types of collapsible hand trucks and dollies. U.S. Pat. No. 1,662,730, issued on Mar. 13, 1928, to Wertenberger et al. shows a stylized truck having a broad surface with suitable caster wheels for transporting bathtubs. U.S. Pat. No. 2,519,113, issued on Aug. 15, 1950, to L. I. Cohn shows a hand truck having a collapsible handle at one end, a stair climbing apparatus, and an adjustable frame. U.S. Pat. No. 2,620,041, issued on Dec. 2, 1952, to Chenette et al. shows a truck having a treaded stair climbing attachment. U.S. Pat. No. 2,820,643, issued on Jan. 21, 1958, to L. I. Cohn shows a hand truck and dolly having an adjustable handle for converting the truck into a dolly. U.S. Pat. No. 3,104,890, issued on Sep. 24, 1963, to N. Hill shows a utility cart having telescoping tubular frame members. U.S. Pat. No. 3,206,790, issued on Sep. 21, 1965, to C. Romay describes a locking assembly for a swiveled caster as used on trucks and other carts. U.S. Pat. No. 3,759,538, issued on Sep. 18, 1973, to A. J. Fabiano illustrates a mobile storage facility having wheels and handles for supporting a tray for garden implements, accessories, and supplies. U.S. Pat. No. 3,761,107, issued on Sep. 25, 1973, to Dochery et al. shows an adjustable dolly for supporting furniture thereon. U.S. Pat. No. 3,837,667, issued on Sep. 24, 1974, to M. A. Sernovitz shows an open-framed cart for receiving containers stacked in a nested relationship. U.S. Pat. No. 4,009,891, issued on Mar. 1, 1977, to O. Jensen provides a hand truck and dolly with an adjustable frame and support chassis. U.S. Pat. No. 4,448,440, issued on May 15, 1984, to R. H. Gier discloses a hand truck having a load supporting platform pivotted to swing from an operative position to a position flush against the frame. U.S. Pat. No. 4,637,626, issued on Jan. 20, 1987, to Foss et al. shows a portable, foldable and convertible luggage trolley. U.S. Pat. No. 4,717,168, issued on Jan. 5, 1988, to J. R. Moon discloses a utility cart having a pair of balloon tire wheels supporting a frame counterbalanced for easy pushing. A pair of caster wheels are provided on the front of the inclined frame. U.S. Pat. No. 4,796,909, issued on Jan. 10, 1989, to V. S. Kirkendall describes a four wheeled pull-type service cart designed to transport heavy loads over sandy terrain. European Patent No. 294,249 shows a dolly having a detachable tubular structure which provides an extendible platform.
[0013] U.S. Pat. No. 5,228,716, issued on Jul. 20, 1993 to the present inventor, teaches a convertible transport cart. After experimentation with the transport cart of this patent, it was found that several improvements were possible. First, it was found that the rectangular frame, although strong, lacked a certain degree of structural integrity. Additionally, it was found that the rectangular frame of this patent inhibited the ability to transport certain small articles (i.e., those articles that had a length less than the width between the bars of the frame). Often, musicians would complain that certain small objects could not be conveniently transported by the cart because of the wide spacing between the sides of the frame. Another problem which was noted was when the cart was configured in its “hand truck” position, there were occasions when the telescoping U-shaped members would slide from one another, especially if the thumbnuts were not sufficiently tightened. The lack of a safeguard mechanism to prevent the members from telescoping apart was a concern to certain users of the cart.
[0014] U.S. Pat. No. 5,476,282, issued in Dec. 19, 1995 to the present inventor, teaches an improved convertible cart for transporting objects having a frame, a first handle connected to the frame, a second handle connected adjacent an opposite end of the frame and a plurality of wheels attached to the frame. Each of the handles is selectively movable between a first position generally perpendicular to the frame and a second position generally aligned with the frames. The wheels support the frame at a position parallel to the surface on which the wheels are placed. The frame has a longitudinal member extending centrally of the frame. The longitudinal member has an end which is offset from overlapping relationship with one end of the frame. A snap button is provided with the longitudinal member so as to limit telescoping movement of one portion of the longitudinal member with respect to the other portion.
[0015] The present inventor has experienced considerable success with the sale of the convertible transport carts identified in U.S. Pat. Nos. 5,228,716 and 5,476,282. However, it was noted that certain improvements could be made in the cart so as to enhance the ability of the cart to satisfy the needs of the consumers. In particular, it is very important and desirable for the convertible transport cart to be made as lightweight as possible while maintaining the full structural integrity of the cart. It has also been found important to be able to configure the cart so that it can be suitably folded for transport in overhead bins of aircraft. As such, the present invention should be configured so as to be as narrow as possible. It has further been found that the wheels of the cart should be configured so as to minimize weight and noise. Along with the ability to minimize the weight of the transport cart, it was found important to create structures which optimally minimize the cost of the production of the cart while maintaining and/or enhancing the structural integrity of the cart. It is important to be able to configure the cart to have eight configurations that can be easily assembled in a minimal amount of time.
[0016] It is an object of the present invention to provide a convertible cart designed to be use in combination with the transport of musical equipment.
[0017] It is an object to provide a cart that will carry up to five hundred pounds, will extend to fifty-two inches in length, weigh less than thirty-five pounds, and collapse to thirty-six inches in length for storage, be durable, and be relatively inexpensive.
[0018] It is another object of the present invention to provide a telescoping and collapsible cart for easy storage.
[0019] It is another object of the present invention to provide foldable handles having a sufficient height to allow for efficient stacking and carrying of delicate musical equipment as well as for allowing for easy storage.
[0020] It is another object of the present invention to provide a cart that is long enough so that the handle folds flat within the framework of the cart.
[0021] It is a further object of the present invention to provide a locking mechanism for the handles of a cart which allows the handles to be positioned up or down within one second each.
[0022] It is a further object of the present invention to provide a cart having handles and a frame that can be arranged so as to maintain a parallel relationship with the earth.
[0023] It is still a further object of the present invention to provide a cart that can be easily transported through airports and the like by having a folded length of three feet or less and a flat side for airport transport belts.
[0024] It is another object to provide a cart that has minimal protrusions for the prevention of snagging, scraping, and injury.
[0025] It is another object to provide a cart that will carry smaller objects as well as larger objects without slipping through the frame. telescoping movement and for preventing telescoping separation of the cart.
[0026] It is still a further object of the present invention to provide a cart that minimizes the weight of the cart.
[0027] It is a further object of the present invention to provide such a cart that minimizes the noise produced by the wheels of the cart.
[0028] It is still a further object of the present invention to provide a cart that is convertible between a short furniture dolly, a two wheel hand truck, a storage/transport configuration, a short hi-stacker cart, a short platform cart, a long platform cart, a long hi-stacker cart, and a longer furniture dolly.
[0029] These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.
[0030] The present invention is a convertible cart for transporting objects that comprises a frame, a first handle connected to the frame adjacent a first end of the frame, a second handle connected to the frame adjacent a second end of the frame, a first plurality of wheels connected to the frame adjacent to the first end of the frame, and a second plurality of wheels connected to the frame adjacent the second end of the frame. The first handle is selectively movable between a first position perpendicular to the frame and a second position generally coplanar with the frame. The frame has a first axle member in engagement with the first handle. The frame has a second axle member in engagement with the second handle. The first handle is rotatable between the first and second positions about the first axle member. The second handle is rotatable between the first and second positions about the second axle member. The first plurality of wheels are rotatably mounted about a tubular axle. The second plurality of wheels are casters rotatably interconnected to the frame.
[0031] In the preferred embodiment of the present invention, each of the first plurality of wheels is a pneumatic tire affixed around the hub. The hub is formed of a polymeric material having a central aperture therein. The central aperture receives roller bearings therein. The roller bearings receive the exterior surface of the tubular axle therein. The tubular axle has a pair of holes formed therein. These holes serve to receive a cotter pin therein at an end of the tubular axle outwardly of the wheel. Each of the second pair of wheels has caster frame pivotally connected to the frame and extending downwardly therefrom. The caster is rotatably mounted within the caster frame. The caster frame specifically includes a generally flat surface in parallel relationship with the frame. The flat surface is pivotally connected to the frame. A first wing member extends transversely outwardly from the flat surface on one side of the flat surface. A second wing member extends transversely outwardly from the flat surface on an opposite side of the flat surface in parallel relationship to the first wing member. The caster is rotatably mounted between the first and second wing members. Each of the first and second wing members has a plurality of holes formed therein and therethrough in spaced relationship downwardly from the flat surface. The caster has a thermoplastic tread bonded to a polymeric hub. The polymeric hub has a plurality of holes formed therein and therethrough and extending in generally spaced radial relationship around the center of the caster.
[0032] The frame has a first frame member and a second frame member in telescopic relationship to each other. The frame has a generally rectangular configuration. The frame is fixable in either a telescoped position or in a retracted position. The second frame member has an end surface extending between the second plurality of wheels. This end surface has a plurality of holes formed therein and therethrough. The plurality of holes are in spaced relationship to each other and extending such that the central axis of the plurality of holes are colinear with each other. The first frame member has a stair climber frame member affixed directly thereto and extending directly outwardly therefrom on an underside of the first frame member. The first frame member also has a second stair climber frame member on an opposite side of the first frame member. The second stair climber frame is in parallel relationship to the first stair climber frame.
[0033] In an alternative embodiment of the present invention, each of the first pair of wheels has a thermoplastic tread bonded to a polymeric hub. The polymeric hub has a central aperture suitable for receiving the tubular axle therein. A plurality of holes are formed therein and therethrough and extend in spaced radial relationship around the central aperture. The polymeric hub has a domed outer surface suitable for contact with an underlying surface. The first pair of wheels are no more than eleven inches apart. The first handle has a length which is less than a length of the second handle.
[0034]
[0035]
[0036]
[0037]
[0038]
[0039]
[0040] FIGS.
[0041]
[0042]
[0043]
[0044]
[0045] With reference to the drawings,
[0046] A stair climber attachment
[0047] A brace
[0048] Inverted U-shaped handles
[0049] The handles
[0050] As can be seen in
[0051] In
[0052]
[0053] The stair climber attachment
[0054] The use of the mild durable square tubular steel material is, by structural design, light enough in weight to be manually lifted onto a truck or into an automobile trunk. It is also structurally sound enough to withstand and support 350 pounds of equipment. The overall empty weight of the cart
[0055] The telescoping frame
[0056] The stair climbing device
[0057] The lateral support bars
[0058]
[0059]
[0060]
[0061] FIGS.
[0062]
[0063]
[0064] The alternative embodiment
[0065]
[0066]
[0067] In the design of the alternative embodiment of the cart
[0068] The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction may be made within the scope of the appended claims without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.