U.S. patent application number 10/725341 was filed with the patent office on 2005-06-02 for anti-slip step for a motor vehicle and a method of forming the same.
This patent application is currently assigned to American Trim, LLC. Invention is credited to Byrne, Robert M., Dalman, Clifford G..
Application Number | 20050117969 10/725341 |
Document ID | / |
Family ID | 34620285 |
Filed Date | 2005-06-02 |
United States Patent
Application |
20050117969 |
Kind Code |
A1 |
Byrne, Robert M. ; et
al. |
June 2, 2005 |
Anti-slip step for a motor vehicle and a method of forming the
same
Abstract
An anti-slip step for a motor vehicle is provided. The step
includes a tread plate with a top surface and a bottom surface. A
plurality of grip structures extend upwardly from the top surface
of the tread plate and a plurality of drain structures extend
downwardly from the bottom surface of the metal plate. Each of the
grip structures and the drain structures at least partially defines
a hole extending through the tread plate. Each of the grip
structures includes a base, having a continuous, curved side wall
that is joined to the tread plate, and a plurality of spaced-apart
tabs joined to the base and extending upwardly therefrom. Each of
the drain structures includes a plurality of spaced-apart tabs
joined to the tread plate.
Inventors: |
Byrne, Robert M.; (Lima,
OH) ; Dalman, Clifford G.; (Spring Lake, MI) |
Correspondence
Address: |
RANKIN, HILL, PORTER & CLARK, LLP
925 EUCLID AVENUE, SUITE 700
CLEVELAND
OH
44115-1405
US
|
Assignee: |
American Trim, LLC
Lima
OH
|
Family ID: |
34620285 |
Appl. No.: |
10/725341 |
Filed: |
December 1, 2003 |
Current U.S.
Class: |
404/19 ;
404/36 |
Current CPC
Class: |
E04F 11/112 20130101;
B60R 3/00 20130101; E04F 15/02172 20130101 |
Class at
Publication: |
404/019 ;
404/036 |
International
Class: |
E01C 011/24 |
Claims
1. An anti-slip step comprising: (a) a tread plate with a top
surface and a bottom surface; (b) a plurality of grip structures
extending upwardly from the top surface of the tread plate, each of
said grip structures at least partially defining a hole extending
through the tread plate and each of said grip structures
comprising: a base having a continuous, curved side wall that is
joined to the tread plate; and a plurality of spaced-apart tabs
joined to the base and extending upwardly therefrom; and (c) a
plurality of drain structures extending downwardly from the bottom
surface of the tread plate, each of said drain structures at least
partially defining a drain hole extending through the tread
plate.
2. The anti-slip step of claim 1, wherein each drain structure
comprises a plurality of spaced-apart tabs.
3. The anti-slip step of claim 2, wherein the tabs of the drain
structures are joined to the tread plate.
4. The anti-slip step of claim 2, wherein the tabs of the drain
structures each have a substantially angular shape.
5. The anti-slip step of claim 1, wherein the tabs of the grip
structures each have a substantially angular shape.
6. The anti-slip step of claim 1, wherein the grip structures are
arranged in at least two rows and the drain structures are arranged
in at least one row, and wherein the at least one row of the drain
structures is disposed between the at least two rows of the grip
structures.
7. The anti-slip step of claim 6, wherein the at least one row of
the drain structures and the at least two rows of the grip
structures are all parallel to each other.
8. The anti-slip step of claim 1, wherein in each of the grip
structures, the base has a plurality of top ends disposed between
the tabs and the tabs have a plurality of top ends, and wherein the
top ends of the tabs have substantially the same length as the top
ends of the base.
9. (canceled)
10. An anti-slip step comprising: (a) a tread plate with a top
surface and a bottom surface: (b) a plurality of grip structures
extending upwardly from the top surface of the tread plate, each of
said grip structures at least partially defining a hole extending
through the tread plate and each of said grip structures
comprising: a base having a continuous, frusto-conical side wall
that is joined to the tread plate; and a plurality of spaced-apart
tabs joined to the base and extending upwardly therefrom; and (c) a
plurality of drain structures extending downwardly from the bottom
surface of the tread plate each of said drain structures at least
Partially defining a drain hole extending through the tread
plate.
11. The anti-slip step of claim 10, wherein the tread plate is
composed of a metal.
12. An anti-slip step comprising: (a) a tread plate with a top
surface and a bottom surface; (b) a plurality of grip structures
extending upwardly from the top surface of the tread plate, each of
said grip structures having a height (H) and at least partially
defining a hole extending through the tread plate, each of said
grip structures comprising: a base having a continuous side wall
joined to the tread plate so as to form a radius of curvature (RC)
between the base and the top surface of the tread plate, wherein
the ratio of the radius of curvature (RC) to the height (H) of the
grip structure is greater than 0.5; and a plurality of spaced-apart
tabs joined to the base and extending upwardly therefrom; and (c) a
plurality of drain structures extending downwardly from the bottom
surface of the tread plate, each of said drain structures at least
partially defining a drain hole extending through the tread
plate.
13-14. (canceled)
15. The anti-slip step of claim 12, wherein the holes of the tread
plate each have a diameter (D), and wherein in each of the grip
structures, the ratio of the height (H) of the grip structure to
the diameter (D) of the hole is less than 0.75.
16. The anti-slip step of claim 15, wherein in each of the grip
structures, the ratio of the height (H) of the grip structure to
the diameter (D) of the hole is less than 0.5.
17. The anti-slip step of claim 12, wherein in each of the grip
structures, the base has a plurality of top ends disposed between
the tabs and the tabs have a plurality of top ends, and wherein the
top ends of the tabs have substantially the same length as the top
ends of the base.
18-22. (canceled)
Description
BACKGROUND OF THE INVENTION
[0001] The present invention generally relates to steps and more
particularly to steps for heavy duty motor vehicles, such as
industrial trucks, to facilitate the ingress and egress of
operators to and from cabs of the trucks.
[0002] Truck steps are conventionally constructed from metal plates
having planar support surfaces. Grip structures are typically
formed in the support surface to prevent slippage, especially when
the step is wet or covered with ice. Drainage holes may also be
formed in the metal plate to allow water to drain from the support
surface. The grip structures are disposed around openings in the
plate and usually have curved side walls defining continuous top
rims. While grip structures of this construction will improve the
grip of a step, the continuous nature of the top rims can still
render the top rims and, thus, the step quite slippery when the
step is wet or covered with ice. In order to address this
deficiency of conventional grip structures, other grip structures
have been developed. Such grip structures are disclosed in U.S.
Pat. No. 3,181,440 to Mullaney et al. and U.S. Pat. No. 4,343,119
to Bahnfleth.
[0003] The rosette of the Bahnfleth patent includes a plurality of
spaced-apart extensions having arcuate edges. The extensions slope
inwardly to provide the rosette with a relatively narrow
cross-shaped opening. Although contact portions of the rosette
edges are discontinuous in a plane of contact, these contact
portions are small. Moreover, the slope of the extensions present
major surfaces that are located just below the contact portions.
These major surfaces can become slippery when the rosette is wet or
covered with ice. Moreover, the narrowness of the opening in the
rosette can make the rosette susceptible to clogging with dirt or
ice.
[0004] The grip structures of the Mullaney et al. patent comprise
cylindrical flanges that extend upright from a metal tread plate
14. Top portions of the flanges are gulleted to provide a number of
fairly deep truncated gripping edges. In order to increase the
height of the flanges and permit the flanges to extend upright, the
flanges are thinned. With the foregoing high-profile construction,
the flanges may trap footwear and cause injury if they are not
properly spaced apart. For this reason, the Mullaney et al. patent
discloses that the flanges must be spaced closely together. Such
close spacing, however, may not always be desirable.
[0005] Based on the foregoing, there is a need in the art for an
improved anti-slip step having low profile grip structures. The
present invention is directed to such an anti-slip step.
SUMMARY OF THE INVENTION
[0006] In accordance with the present invention, an anti-slip step
for a motor vehicle is provided. The step includes a tread plate
with a top surface and a bottom surface. A plurality of grip
structures extend upwardly from the top surface of the tread plate.
Each of the grip structures at least partially defines a hole
extending through the tread plate. Each of the grip structures
includes a base having a continuous, curved side wall that is
joined to the tread plate. A plurality of spaced-apart tabs are
joined to the base and extend upwardly therefrom. A plurality of
drain structures extend downwardly from the bottom surface of the
tread plate. Each of the drain structures at least partially
defines a drain hole extending through the tread plate.
[0007] In accordance with another feature of the present invention
each of the grip structures has a height (H) and the side wall of
the base is joined to the tread plate so as to form a radius of
curvature (RC) between the base and the top surface of the tread
plate, wherein the ratio of the radius of curvature (RC) to the
height (H) of the grip structure is greater than 0.5.
[0008] Also provided in accordance with the present invention is a
method of forming an anti-slip step. Pursuant to the method, a
tread plate is provided having top and bottom surfaces. A plurality
of holes are formed in the tread plate. For at least one of the
holes, a boundary region of the tread plate disposed around the
hole is bent so as to extend out of the plane of the top surface
and thereby form a first structure at least partially defining a
first opening. For at least another one of the holes, a boundary
region disposed around the hole is bent so as to extend out of the
plane of the top surface and thereby form a second structure at
least partially defining a second opening, wherein the second
structure extends a farther distance from the tread plate than the
first structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The features, aspects, and advantages of the present
invention will become better understood with regard to the
following description, appended claims, and accompanying drawings
where:
[0010] FIG. 1 is a perspective view of a step;
[0011] FIG. 2 is an elevational view of a grip structure in a tread
plate of the step;
[0012] FIG. 3 is an elevational view of a drain structure in the
tread plate of the step;
[0013] FIG. 4. is a vertical sectional view of the grip
structure;
[0014] FIG. 5 is a vertical sectional view of the drain
structure;
[0015] FIG. 6 is a plan view of a hole in the tread plate from
which the grip structure is formed; and
[0016] FIG. 7 is a plan view of a hole in the tread plate from
which the drain structure is formed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] It should be noted that in the detailed description that
follows, identical components have the same reference numerals,
regardless of whether they are shown in different embodiments of
the present invention. It should also be noted that in order to
clearly and concisely disclose the present invention, the drawings
may not necessarily be to scale and certain features of the
invention may be shown in somewhat schematic form.
[0018] Referring now to FIG. 1, there is shown a portion of a step
10 embodied in accordance with the present invention. The step 10
is adapted for installation on a motor vehicle, especially an
industrial truck having an elevated cab, such as a dump truck or a
tractor for pulling a semitrailer. The step 10 includes a support
structure 12 that is preferably composed of a metal, such as
aluminum. The support structure 12 includes a tread plate 14, a
pair of opposing end flanges 16, front flange 18 and a rear flange
(not shown). The tread plate 14 is rectangular and includes top and
bottom surfaces 22, 24. The end flanges 16 are joined at bends to
opposing end portions of the tread plate 14, respectively, and
extend downwardly therefrom. Although not shown, the end flanges 16
may have holes formed therein for receiving screws, bolts or other
elongated fasteners that may be used to secure the step 10 between
side supports of a stair. The front flange 18 and the rear flange
are joined at bends to opposing side portions of the tread plate
14, respectively, and extend downwardly therefrom. Each of the
front flange 18 and the rear flange has an L-shaped cross-section
and includes a downwardly-extending first member 26 joined at a
bend to an inwardly-extending second member 28 so as form an
interior ledge. In each of the front flange 18 and the rear flange,
the first and second members 26, 28 are preferably disposed at
least substantially perpendicular to each other. The second members
28 of the front and rear flanges 18, 20 are preferably disposed at
least substantially parallel to the tread plate 14. The support
structure 12 is preferably formed from a single metal plate by
appropriately cutting out the corners of the single plate and
appropriately bending front, rear and end portions of the single
plate to form the end flanges 16, the front flange 18 and the rear
flange, respectively.
[0019] A plurality of grip structures 32 and drain structures 34
extend from the tread plate 14 and at least partially define a
plurality of grip openings 36 and drain openings 38 in the tread
plate 14, respectively. The grip structures 32 extend upwardly from
the top surface 22 of the tread plate 14, while the drain
structures 34 extend downwardly from the bottom surface 24 of the
tread plate 14. The grip structures 32 provide non-continuous
gripping to footwear brought into contact with the tread plate 14,
while the drain structures 34 facilitate the drainage of water from
the top surface 22 of the tread plate 14 so as to prevent the
pooling of water thereon.
[0020] Preferably, the grip structures 32 and the drain structures
34 are arranged such that the tread plate 14 has alternating
longitudinally-extending rows of grip structures 32 and drain
structures 34. In the specific version of the invention disclosed
in FIG. 1, there is a longitudinal middle row of drain structures
34 disposed between longitudinal front and rear rows of the grip
structures 32. It should be appreciated, however, that the present
invention is not limited to this particular arrangement of the grip
structures 32 and the drain structures 34.
[0021] Referring now to FIGS. 2 and 4, each of the grip structures
32 comprises a curved base 40 that is joined to the top surface 22
of the tread plate 14. The base 40 preferably comprises a
continuous curved side wall. More preferably, the base 40 comprises
a frusto-conical side wall. A plurality of tabs 42 are joined to
the base 40 and extend upwardly therefrom. The base 40 and each of
the tabs 42 have at least substantially the same thickness as the
thickness of the tread plate 14. Preferably, each of the tabs 42
has a substantially angular shape, with a pair of non-parallel
sides 42a extending downwardly and outwardly from opposing ends of
a free top end 42b. Bottom portions of the tabs are 42 integrally
joined to top portions of the base 40. The tabs 42 at least
partially define the grip opening 36, which has a diameter "D1", as
is best shown in FIG. 4. The tabs 42 are spaced apart around the
periphery or circumference of the base 40 so as to cooperate with
the base 40 to form a plurality of alternating ridges and valleys,
wherein the ridges are comprised of the top ends 42b of the tabs 42
and the valleys are comprised of top end portions 40a of the base
40. The sides 42a of the tabs 42 are joined to the top end portions
40a of the base 40 at bends. Both the top ends 42b of the tabs 42
and the top end portions 40a of the base 40 are slightly arcuate in
the horizontal direction. Outer and inner edges of both the top
ends 42b of the tabs 42 and the top end portions 40a of the base 40
are preferably uniform in height along their lengths. In addition,
the top ends 42b of the tabs 42 are substantially horizontally
disposed. The top end portions 40a of the base 40, however, slope
slightly inward. The top ends 42b of the tabs 42 are disposed a
height "H" above the top surface 22 of the tread plate 14, i.e.,
each grip structure 32 has a height "H". Preferably, the top end
portions 40a of the base 40 have at least substantially the same
arcuate length as the top ends 42b of the tabs 42.
[0022] In each grip structure 32, the base is joined to the top
surface of the tread plate 14 so as to form a radius of curvature
RC1 between the base and the top surface, wherein the ratio of the
radius of curvature RC1 to the height H1 of the grip structure
(i.e., RC1/H) is greater than 0.5, more preferably greater than
0.75, still more preferably greater than 1. In addition, each grip
structure is constructed such that the ratio of the height H of the
grip structure to the diameter D1 of the grip opening of the grip
structure (i.e., H/D1) is less than 0.75, more preferably less than
0.5, still more preferably less than 0.3. Furthermore, the ratio of
the height H of each grip structure 32 to the thickness "T" of the
tread plate 14 (i.e., H/T) is preferably less than 3, more
preferably less than 2. With the IS foregoing structure, the grip
structures 32 have low profiles that do not require the grip
structures 32 to be disposed closely together.
[0023] Referring now to FIGS. 3 and 5, each of the drain structures
34 comprises a plurality of tabs 46 joined to the bottom surface 24
of the tread plate 14 and extending downwardly therefrom. The tabs
46 have at least substantially the same thickness as the thickness
of the tread plate 14. Preferably, each of the tabs 46 has a
substantially angular shape, with a pair of non-parallel sides 46a
extending upwardly and outwardly from opposing ends of a free
bottom end 46b. Top portions of the tabs 46 are integrally joined
to the bottom surface 24 of the tread plate 14. The tabs 46 at
least partially define the drain opening 38, which has a diameter
"D2", as best shown in FIG. 5. The bottom ends 46b of the tabs 46
are disposed a distance or depth "Dp" below the bottom surface 24
of the tread plate 14, i.e., each drain structure 34 has a depth
"Dp".
[0024] In each drain structure 34, each tab 46 is joined to the
bottom surface 24 of the tread plate 14 so as to form a radius of
curvature RC2 between the tab 46 and the bottom surface 24, wherein
the ratio of the radius of curvature RC2 to the depth Dp of the
drain structure 34 (i.e., RC2/Dp) is greater than 1, more
preferably greater than 2, still more preferably greater than 3.
Preferably, the radius of curvature RC2 of the drain structures 34
is at least substantially the same as the radius of curvature RC1
of the grip structures 32.
[0025] The diameter D2 of the drain openings 38 of the drain
structures 34 is preferably at least substantially the same as the
diameter D1 of the grip openings 36 of the grip structures 32. The
depth Dp of the drain structures 34, however, is preferably less
than the height H of the grip structures 32. Still more preferably,
the ratio of the depth Dp of the drain structures 34 to the height
H of the grip structures 32 (Dp/H) is less than 1, more preferably
less than 0.75, still more preferably less than 0.5.
[0026] In lieu of having the construction described above, the
drain structures 34 may have the same structure (with the same
dimensions) as the grip structures 32 (except for extending
downwardly from the bottom surface 24), wherein the tabs 46 are
joined to bases joined to the bottom surface 24.
[0027] Preferably, each of the grip structures 32 and each of the
drain structures 34 is formed using a punching operation and an
embossing operation, wherein in the punching operation, a hole is
formed in the tread plate 14, and in the embossing operation, a
boundary region of the tread plate 14 around the hole is pushed
away from the tread plate 14 so as to extend out of the plane of
the tread plate 14, i.e., so as to extend out of the plane of the
top surface 22 or the bottom surface 24, as the case may be. The
holes for forming the drain structures 34 are similar to the holes
for forming the grip structures 32, except the holes for forming
the drain structures 34 are about 13% larger than the holes for the
grip structures 32 and except for the difference noted below. In
another embodiment of the present invention, all of the holes for
the grip structures 32 and the drain structures 34 have the same
size and configuration.
[0028] One of the holes for the grip structures 32, designated with
the reference numeral 50, is shown in FIG. 6. The hole 50 is
generally star-shaped and is defined by a plurality of interior
edges of the tread plate 14 that define tabs 52 that will become
the tabs 42 for the grip structure 32. The interior edges of the
tread plate 14 include radially-inward first edges 54 and
radially-outward second edges 56, which respectively correspond to
the top ends 42b of the tabs 42 and the top end portions 40a of the
bases 40. Each of the first and second edges 54, 56 has a slight
outward bend (about 8 degrees) to permit the top ends 42b of the
tabs 42 and the top end portions 40a of the base 40 to be smoothly
formed when the boundary region (designated by the reference
numeral 58) of the tread plate 14 around the hole 50 is pushed
outward. The boundary region 58 has an outer perimeter 60 shown by
a circular dashed line.
[0029] One of the holes for the drain structures 34, designated
with the reference numeral 62, is shown in FIG. 7. The hole 62 is
also generally star-shaped and is defined by a plurality of
interior edges of the tread plate 14 that define tabs 64 that will
become the tabs 46 for the drain structure 34. The interior edges
of the tread plate 14 include radially-inward first edges 66 (which
respectively correspond to the bottom ends 46b of the tabs 46) and
radially-outward second edges 68. Each of the first and second
edges 66, 68 has a slight outward bend (about 10 degrees) to permit
the bottom ends 46b of the tabs 46 to be smoothly formed when the
boundary region (designated by the reference numeral 70) of the
tread plate 14 around the hole 62 is pushed outward. The boundary
region 70 has an outer perimeter 72 shown by a circular dashed
line.
[0030] Once the holes 50, 62 are formed in the tread plate 14, the
boundary regions 58, 70 of the tread plate 14 around the holes 50,
62 are contacted by embossing dies on a press and pushed upwardly
or downwardly (depending on the arrangement of the press and the
support structure 12) to form the grip structures 32 and the drain
structures 34. With regard to the hole 50 for a grip structure 32,
the boundary region 58 extends radially outward from the second
edges 56 to form an annular portion between the second edges 56 and
the outer perimeter 60 of the boundary region 58. With regard to
the hole 62 for a drain structure 34, the boundary region 70 has a
radius about equal to the distance of the second edges 68 from the
center of the hole 62. The boundary regions 58 for the holes 50 are
determined by the radii of the dies for the grip structures 32, and
the boundary regions 70 for the holes 62 are determined by the
radii of the dies for the drain structures 34. The dies for the
grip structures 32 have larger radii than the dies for the drain
structures 34.
[0031] When the dies for the drain structures 34 are aligned with
the holes 62 and pressed against the tread plate 14, the dies for
the drain structures 34 only contact the tabs 64 and bend them to
form the tabs 46 for the drain structures 34, whereas when the dies
for the grip structures 32 are aligned with the holes 50 and
pressed against the tread plate 14, the dies for the grip
structures 32 contact the annular portions of the tread plate 14
disposed radially outward from the second edges 56 and bend them to
form the bases 40 for the grip structures 32.
[0032] From the foregoing description, it should be appreciated
that the step 10 of the present invention is simple to produce, has
improved anti-slip features and facilitates the drainage of water
from the step 10. The low profile of the grip structures 32 permits
the grip structures 32 to be more spread out without increasing the
risk of trapping footwear.
[0033] While the step 10 is especially adapted for use on an
industrial truck having an elevated cab, the step 10 can also be
used in other applications, such as on ships, locomotives and on
fixed structures, such as elevated industrial walkways.
[0034] While the invention has been shown and described with
respect to particular embodiments thereof, those embodiments are
for the purpose of illustration rather than limitation, and other
variations and modifications of the specific embodiments herein
described will be apparent to those skilled in the art, all within
the intended spirit and scope of the invention. Accordingly, the
invention is not to be limited in scope and effect to the specific
embodiments herein described, nor in any other way that is
inconsistent with the extent to which the progress in the art has
been advanced by the invention.
* * * * *