Land vehicles – Wheeled – Tiltable vehicles – stabilized by attendant or article
Reexamination Certificate
1999-11-23
2002-11-19
Johnson, Brian L. (Department: 3618)
Land vehicles
Wheeled
Tiltable vehicles, stabilized by attendant or article
C280S047270, C029S897200
Reexamination Certificate
active
06481727
ABSTRACT:
BACKGROUND OF THE INVENTION
The toe plate of a hand truck is located at the lower front edge of the truck adjacent to the ground and functions to support the load being transported with a horizontal angular portion cantilevered outward which transmits the weight of the load to the remaining structure of the hand truck. The horizontal portion of the toe plate is the most highly stressed part of the hand truck as to any bending loads.
Traditionally, toe plates have been either cast aluminum or a welded steel plate fabrication. Since the end of the toe plate must sustain substantial bending loads, light-gauge steel plate has not been utilized until the design of the present invention.
SUMMARY OF THE INVENTION
The toe plate of the present invention is formed from a relatively light gauge coiled steel sheet which forms the toe plate through a series of automated steps including punching and forming. The first step involves forming a series of three longitudinal ribs in the horizontal load supporting portion of the toe plate and three additional ribs in the vertical mounting portion of the toe plate which are aligned with the three ribs in the horizontal portion of the plate.
The second progression or step of the tooling stamps a series of mounting holes in the vertical portion of the toe plate and also shapes the ends of the toe plates leaving a small tab area so as to retain the still-flattened toe plates as a part of the feed sheet coming off the coil.
In the third progression, lateral side notches are cut in the sheet defining the horizontal portion of the toe plate from the vertical mounting portion of the toe plate.
The fourth progression step bends the mounting ears back through a 90 degree bend from the mounting portion of the toe plate.
The fifth progression step forms a 90 degree bend between the horizontal load supporting portion of the plate and the vertical mounting portion of the toe plate as the dies come together in the fifth progression. Also in the fifth step, three additional rib areas are formed in the toe plate between the horizontal load portion and the vertical mounting portion and these additional rib areas connect the previously formed six ribs from the first step into three continuous ribs which pass through the 90 degree bend between the horizontal and vertical portions of the toe plate. These continuous three ribs add substantial bending strength to the relatively thin gauge sheet stock from which the toe plate has been formed. Also in progression step five, the tab areas connecting each toe plate to the progressing coil sheet are severed prior to the 90 degree bend. In the fifth stage, an additional gusset rib is formed across the top of the vertical mounting portion between the two mounting ears to provide additional reinforcement in the mounting area of the toe plate. The completed toe plate is formed in a single piece having three reinforcing ribs which extend across the horizontal portion of the toe plate and extend up into the vertical mounting areas of the toe plate so as to provide a relatively high bending strength toe plate formed from a relatively thin gauge of sheet stock. The three reinforcing ribs which extend from the horizontal portion of the toe plate through the 90 degree bend to the vertical portion of the toe plate add substantial strength to the toe plate thus permitting the use of a much simplified form with a substantial weight reduction over previously cast or welded toe plate designs.
The principal objective of the present invention is to provide an inexpensive lightweight toe plate design formed from coiled sheet stock with automated tooling without any welding or assembly requirements.
REFERENCES:
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patent: 2921798 (1960-01-01), Cislak
patent: 3361439 (1968-01-01), Olson
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patent: 3927898 (1975-12-01), Weyrauch
patent: 4120065 (1978-10-01), Sivachenko
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patent: 5186571 (1993-02-01), Hentzschel
patent: 5419600 (1995-05-01), Tisbo
patent: 5549317 (1996-08-01), Dunkle
patent: 5564248 (1996-10-01), Callies
patent: 5749588 (1998-05-01), Stallbaumer
patent: D395105 (1998-06-01), Stallbaumer
Sheet Metal Fabricating, Reinhold Publising Corp., 1951.*
Magliner Catalog 1997 and attached web page from 2000.
Bottorff Christopher
Brown, Jr. Edward L.
Harper Trucks, Inc.
Johnson Brian L.
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