Land vehicles – Wheeled – Body with bracketed-type or nonsuspended axles
Reexamination Certificate
2001-02-23
2003-07-15
Lerner, Avraham (Department: 3611)
Land vehicles
Wheeled
Body with bracketed-type or nonsuspended axles
C280S047300, C016S029000, C016S030000
Reexamination Certificate
active
06592134
ABSTRACT:
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
None.
FIELD OF THE INVENTION
The present invention pertains to methods and apparatus for assisting a person when, alone or with others, he or she moves a ladder from place-to-place, as for example, from its storage place to a work site or one work site to another.
BACKGROUND OF THE INVENTION
Many kinds of ladders and stepping-stools are known which are mounted on wheels and casters that automatically or manually retract when a person's weight is placed on their steps. The casters facilitate movement of the ladder from one location to another. For safety purposes, the casters retract so that the ladder legs rest on the supporting surface, usually a floor or the ground. Some ladders are either too large or too cumbersome for one person to carry easily and without potential for injury. Some of these ladders use caddies, dollies or wheeled attachments to facilitate transport by a single person. However, many ladders are made with no such device.
U.S. Pat. No. 4,564,203 to Ronald Williams and dated Jan. 14, 1986, discloses an aid for transporting a narrow oblong object (such as a ladder leg 72. His device does not permit the ladder to be erected on the wheel-supported end without removing the concave socket and wheel assembly (releasable embodiment 70). Therefore this embodiment of the device is not easily usable on the step ladder shown earlier in the drawings since it can only be placed on the free end of the step ladder legs 33 and must be removed before that ladder can be erected in order that an appropriate surface support the ladder legs. That embodiment 70 is also not easily used on an extension ladder. Assuming that it is clamped to the topmost end of an erect ladder, an irregular and flimsy element 74, 79 is then placed against the wall against which the ladder top is supported, a potential safety hazard. If it is placed on the lower segment of the ladder, the socket interferes with the upper segment's flush fit on the lower segment. In order to transport the it, the ladder must be fully lowered and then swung right or left or allowed to drag down the surface against which it was leaning in order to place the wheel on the ground or other supporting surface. This is difficult to do with very long or heavy ladders. The most appropriate position for this device being at the lower ends of the ladder legs, the user is compelled to remove it in order to safely mount the ladder. Williams has provided a narrow wheel for end support. His wheel, therefore, must be moved from side-to-side and pinned in place to prevent the ladder from tipping. Finally, since the ladder leg must fit into the concave socket 73, such a socket can not be sized universally for all sizes and shapes of ladder legs.
In his U.S. Pat. No. 3,580,601, dated May 25, 1971, Ray P. Miller discloses a skate device for transporting unwieldy, flat objects with ease. The device comprises an elongated base member containing a pair of brackets at each end and a clamping bracket member at its midsection. Rollers are provided on the bottom of the base member and are all in line. The end rollers are mounted slightly above the midsection roller to enable the skate to be tipped backward or forward on the end rollers for maneuverability. The skate is clamped to an edge of the flat object for transporting. Miller's device is limited to placement along a thin edge of flat, heavy objects with large surface areas (col. 1, line 3-5) such as doors, sheet rock, plywood, etc. Its elongated base member is large, heavy, and can not reasonably be left in place on an ordinary ladder in use and therefore has marginal utility for ladder transport.
U.S. Pat. No. 5,566,780, dated Oct. 22, 1996 was issued to Harry M. Hambrough. It describes a combination cart and ladder apparatus including a first and a second ladder assembly. Such devices are often used for hunting. A pair of wheel assemblies are supported by the first ladder assembly at preselected positions on its length. Translation of the second ladder assembly with respect to the first ladder assembly is not interfered with by the wheel connection assemblies. A first platform assembly is connected to distal ends of second lateral support members. A stop element is connected to a bottom side of the first platform element. The stop element includes a fixed portion connected to the first platform element and a free-end portion projecting from the fixed portion at an obtuse angle. A strap assembly is connected to the first platform element and connects the apparatus to a tree. When the combination cart and ladder is used to provide an elevated platform in a tree, the fork assembly which holds the wheels is adjusted so they are no longer in contact with the ground. Wheel brakes are, therefore, not needed. Applicants' wheels need no adjustment when the ladder is erected since they are placed in a position which obviates their contact with ground except when the ladder is being transported. Applicants' ladder with transport attachment is not intended to be used as a cart for moving other objects.
Peter DiSario's U.S. Pat. No. 5,727,799 presents a dolly for supporting a ladder during movement to a work site. The dolly has a frame adapted to be attached by clips to the rungs of the ladder. The dolly has a single, relatively large wheel in terms of ladder width pivotally mounted on the frame for supplying rolling support in order to enable a single individual to move a long, heavy ladder over sloping or rough ground. The wheel assembly is very large and because of its position in the center of the ladder side rails or legs where the user would ordinarily mount the ladder, it prohibits use of the ladder when it is erected, unless the wheel and frame are completely removed or the ladder can be placed against a wall allowing clearance for the wheel. With DiSario's caddy, the ladder cannot be transported on its edge.
U.S. Pat. No. 5,086,872 to Fan-Nam Lim discloses a foldable ladder equipped with a pair of wheels so the ladder can be converted into a push cart for transportation of various goods with ease. The foldable ladder is made up of a number of sections joined together one by one by adjustable knuckles which can be put in a number of positions so the ladder can be transformed into a plurality of forms of cart when a pair of wheels are removably attached to the bottom of the ladder. The heavy-duty wheels and axle are not easily removed, being bolted to the ladder legs and spanning across the width of the ladder. This configuration permits transport of the ladder device basically as a cart, the width being constrained parallel to the supporting surface, floor or ground. As a result, the ladder can not be transported on edge as may be required to pass through narrow doorways.
Brookes et al. in their U.S. Pat. No. 4,049,283 describe a caddy for transporting a heavy ladder to a work site. The caddy is formed of a pair of transverse pieces having resilient clips installed thereon adapted to engage and clamp onto any rung of the ladder. The pieces are attached at spaced positions to the bridge of a two-wheeled carriage so that the pieces are adapted to straddle and engage a pair of adjacent rungs on the ladder in wheel-barrow position. The caddy must be disengaged and removed from the ladder before the ladder can be erected for use.
James R. Wilson in his U.S. Pat. No. 5,382,032, dated Jan. 17, 1995 discloses a wheeled stepladder dolly wherein the dolly is engageable with both a step of the ladder and existing cross braces on the support portion of a conventional stepladder to temporarily hold the step ladder in fixed relationship with the dolly, thus providing a stepladder dolly assembly to be used for transporting heavy boxes of tools and the like. The engagement means are adjustable and configured to be adaptable for a number of brands and varieties of commercially available stepladders. Wilson describes a means for transporting a stepladder and heavy objects placed on the face of the ladder. However, it appears that the
Giaacherini Thomas N.
Inovent, Inc.
Lerner Avraham
LandOfFree
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