Information
-
Patent Grant
-
6499563
-
Patent Number
6,499,563
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Date Filed
Thursday, June 14, 200123 years ago
-
Date Issued
Tuesday, December 31, 200222 years ago
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Inventors
-
Original Assignees
-
Examiners
- Stodola; Daniel P.
- Thompson; Hugh B.
Agents
- Harness, Dickey & Pierce, P.L.C.
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CPC
-
US Classifications
Field of Search
US
- 182 107
- 182 108
- 182 214
- 182 129
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International Classifications
-
Abstract
A protective ladder cap for fitting over the end of a rail of a ladder is provided. The cap has an open end for fitting over the rail and a closed end. The ladder cap has tapered internal ribs for engaging the end of a side rail of a ladder. The ladder caps prevent the ladder side rails from damaging the surface upon which the ladder leans when in use.
Description
FIELD OF THE INVENTION
The present invention relates to ladders and, more particularly, to protective caps that secure over the ends of the rails of a ladder to protect the surface upon which the ladder leans when in use.
BACKGROUND OF THE INVENTION
Ladders have been used for decades by homeowners and commercial entities. Without a doubt, ladders provide great utility to those that use them. In decades past, most ladders were made of wood, but that has changed. Most ladders today are made of aluminum or fiberglass. Aluminum or fiberglass is desirable because the materials are lightweight and durable. Nonetheless, the rails that form the sides of the ladder have a tendency to cause damage to the surface upon which they are leaning. Further, hard plastic end pieces are often times used to protect the ends of the rails and are prone to damage the surface upon which they rest. It is not uncommon for the ladders to leave scratches and marks on, for example, vinyl siding.
Industry recognized this problem and, for a number of years, has offered protective caps that fit over the ends of the ladder rails. The caps are typically made from a pliable plastic. The caps serve to protect the surface upon which the ladder leans.
A problem, however, not addressed by the prior art is that ladder rails are not all sized the same. Thus, a protective cap designed to fit on one ladder rail will not fit on all ladder rails. If a user attempts to place a protective cap that is larger than the ladder rail cross-section, the cap will not fit securely on the ladder and can easily fall off the ladder rail. If a user attempts to place a protective cap on the ladder rail that is too small, it may not fit at all, or, if forced over the ladder rail, it may split after some time or during use. Further, the user often times does not know the size of the ladder rail. It is therefore much easier to buy a product that is adapted to fit over a broader range of varying sized side rails
SUMMARY OF THE INVENTION
This invention is directed to a protective ladder cap for fitting over the end of a rail of a ladder. The cap has an open end for fitting over the rail and a closed end. The cap has at least one elongated internal rib that tapers from a lower rib height closer to the open end than the closed end to a higher rib height closer to the closed end than the open end. In the preferred embodiment, the cap includes a plurality of internal ribs. The internal ribs also preferably comprise an indent portion adjacent the closed end of the rail to secure the cap on the ladder rail.
In the preferred embodiment, the protective ladder cap has two wide internal faces and two narrow internal faces. The internal ribs are on at least one of the wide internal faces, and preferably both. In an even more preferred embodiment, the internal ribs are on the narrow faces as well.
Because the internal ribs taper from a lower height to a higher height, the ladder cap is adapted to receive ladder rails of varying cross-section. Further, the tapered ribs ensure that the ladder cap is secured to the ladder, thus minimizing the ability of the ladder cap to fall off of the ladder rail. Because the ladder cap of the present invention is able to securely fit on ladder rails having varying cross-sections, consumers purchasing ladder caps are not required to know the cross-section size of their ladder rails. Thus, the ladder cap of the present invention also makes it much easier for consumers to purchase a ladder cap that fits snugly on the consumer's ladder.
These and other aspects of the invention are described more fully below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a perspective view of the ladder cap of the present invention shown as attached to the ends of the side rails of the ladder;
FIG. 2
is a perspective view of the ladder cap of the present invention;
FIG. 3
is a cross-sectional view of the ladder cap, taken along the plane parallel to the side face of the ladder cap and represented by section line
3
—
3
in
FIG. 5
;
FIG. 4
is a cross-sectional view of the ladder cap, taken along the plane parallel to the side face of the ladder cap and represented by section line
4
—
4
in
FIG. 5
; and
FIG. 5
is a cross-sectional view of the ladder cap, looking directly into the ladder cap and taken along the plane represented by section line
5
—
5
in FIG.
3
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to
FIG. 1
, the present invention is directed to a protective ladder cap
10
that is adapted to fit on a ladder
12
. The ladder, as is well known, typically includes two side rails
14
and a plurality of rungs
16
(only one shown) that are spaced apart to provide steps for the user. The ladder cap
10
is sized to fit over the ends of the side rails
14
to protect the surface upon which the ladder is resting.
As shown in
FIG. 2
, the protective ladder cap
10
comprises a cap
18
that has an open end
20
and a closed end
22
. The open end
20
is sized to fit over the end of the side rails. The opening is defined by the length from point
24
to point
26
, which is preferably about 3.5 inches and the length from point
28
to point
30
, which is preferably about 1.25 inches. The dimensions are sized to allow the ladder cap
10
to be easily slid over the ends of the side rails
14
. Referring to
FIGS. 3 and 4
, the inner surface
32
of the closed end
22
typically abuts against the ends of the side rails when the ladder cap is pushed onto the ladder side rails
14
. The cap
18
includes two wide sidewalls
34
and two narrow sidewalls
36
, which together with the top or closed end
22
form the cap
18
.
As shown best in
FIG. 3
, the ladder cap
10
includes two opposed side detents
38
that protrude inwardly to engage the side rails. From the detents
38
, the two wide sidewalls extend outwardly to the closed end
22
at approximately six degrees and the two narrow sidewalls extend outwardly to the closed end
22
at approximately fourteen degrees (i.e., both walls are angled outwardly slightly). The total height of the ladder cap
10
from the open end
20
to the closed end
22
is approximately 5.5 inches. The total height from the open end
20
to the middle of the detents
38
is approximately 2 inches.
The two wide sidewalls
34
of the ladder cap
10
have internal wide faces
40
and the two narrow sidewalls have internal narrow faces
42
. In the preferred embodiment, the ladder cap
10
includes a plurality of elongated internal wide face ribs
43
on the internal wide faces
40
, as shown in
FIGS. 3 and 5
. Referring to
FIG. 4
, the length of each wide face rib
43
is approximately 3 inches, and the height tapers from point
44
to a height of approximately 0.094 inches at point
46
. The taper from point
44
to point
48
is less than the taper from point
48
to point
50
. At point
48
, the height of the rib is approximately 0.219 inches and at point
50
the height of the rib is approximately 0.344 inches. The height at point
51
is approximately 0.438 inches. The internal wide ribs
43
preferably include a height of at least 0.250 inches and the rib is preferably tapered from a lower height of around zero inches to the maximum height, as shown in
FIG. 4
at point
51
. Nonetheless, it is appreciated that the lower height could be more than zero. The lower the height, however, the easier to facilitate a smooth engagement by the end of the ladder rail onto the surface of the internal rib. It should also be understood that the terms “narrow” and “wide” as used herein are used simply as descriptive terms to distinguish between the various sides; the terms should not be construed to be limited to a particular dimension or size.
The wide face ribs
43
also include an indent portion
52
in the preferred embodiment. The indent portion together with the closed end
22
forms a u-shaped channel. The depth from point
51
to the bottom
54
of the indent portion
52
is approximately 0.344 inches. The width of each wide face rib
43
is approximately 0.100 inches and the distance between each rib is approximately 0.210 inches. As shown in
FIG. 5
, wide face ribs
43
extend inwardly beyond the open end
20
such that when the ladder cap
10
is slid on the end of a side rail
14
through open end
20
, the side rail
14
engages the tapered internal wide face ribs
43
. If the ladder cap
10
is pushed onto the side rail
14
sufficiently, the side rail lodges into the indent portion
52
, further holding the ladder cap
10
on the side rail.
In the preferred embodiment, the ladder cap
10
also has narrow face ribs
60
on the internal narrow faces
42
, as shown in
FIGS. 3 and 5
. The narrow face ribs
60
are approximately the same length as the wide face ribs
43
. The rib height tapers from point
62
to a height of approximately 0.438 inches at point
64
to a height of approximately 0.750 inches at point
66
. The width of each narrow face rib
43
is approximately 0.100 inches and the distance between each rib is approximately 0.210 inches.
It should be understood that the dimensions are only illustrative. One skilled in the art can readily appreciate how to alter the dimensions provided without departing from the spirit and scope of the invention. The same is true with respect to the number of internal ribs. In fact, the present invention would work, although not preferably, with only one thicker internal rib that engages the side rail when it is inserted into the ladder cap
10
. Also, the product will perform well with ribs on only the internal wide faces
40
and will work adequately if the ribs are located only on the side faces
42
. By placing ribs on opposed faces, the ladder cap
10
slides over the side rail
14
more evenly and increases the surface area of frictional engagement. In the preferred embodiment, the ladder cap
10
includes at least 5 internal wide face ribs on each wide face
40
and at least two narrow face ribs.
In use, the ladder cap
10
is slid over the end of a side rail
14
through open end
20
. The side rail
14
engages the internal ribs
43
and
60
. To the extent the ladder cap
10
is slid over a side rail
14
all the way, the side rail
14
should become lodged in not only the detents
38
but also the unshaped channel formed by the indent portions
52
and the closed end
22
, thus further securing the ladder cap
10
to the side rail
14
. The wide sides
34
and the narrow sides
36
that extend upwardly beyond the detents
38
to form the closed end
22
are approximately 0.250 inches thick.
The ladder cap is preferably made out of a PVC plastic that is a dielectric material. In the preferred embodiment, the material is plastisol.
While a preferred protective ladder cap has been described in detail, various modifications, alterations, and changes may be made without departing from the spirit and scope of the ladder cap according to the present invention as defined in the appended claims.
Claims
- 1. A ladder cap comprising:a cap for fitting over the end of a rail of a ladder, the cap having an open end for fitting over the rail and a closed end, the cap including opposed side walls and opposed end walls, each of the walls being tapered and wider at about the closed end and narrower at about the open end; and at least one elongated internal rib that tapers from a lower rib height closer to the open end than the closed end to a higher rib height closer to the closed end than the open end.
- 2. The ladder cap of claim 1 wherein the internal rib further comprises an indent portion adjacent the closed end of the cap.
- 3. The ladder cap of claim 2 wherein the indent portion of the internal rib and the closed end define a channel for receiving at least a portion of the rail when the cap is fitted over the end of the rail.
- 4. The ladder cap of claim 1 wherein the cap includes a plurality of the internal ribs.
- 5. The ladder cap of claim 4 wherein the internal ribs include an indent portion adjacent the closed end of the cap.
- 6. The ladder cap of claim 5 wherein the ladder cap is made of a dielectric material.
- 7. The ladder cap of claim 6 wherein the material is polyvinyl chloride plastisol.
- 8. The ladder cap of claim 4 wherein the ladder cap has two wide internal faces and two narrow internal faces and the internal ribs are on at least one of the wide internal faces.
- 9. The ladder cap of claim 8 wherein the internal ribs are on the two wide internal faces.
- 10. The ladder cap of claim 9 wherein the internal ribs are on the two wide faces Ad and the two narrow faces.
- 11. The ladder cap of claim 1 wherein there are at least five internal ribs on each wide face.
- 12. The ladder cap of claim 11 wherein the higher rib height of the internal ribs is at least ¼ of an inch in height.
- 13. The ladder cap of claim 1 wherein there are at least five internal ribs on each wide face and there are at least two internal ribs on each narrow face.
- 14. The ladder cap of claim 13 wherein the higher rib height of the internal ribs on each wide face are at least ¼ of an inch and the higher rib height of the internal ribs on each narrow face are at least ⅜ of an inch in height.
- 15. The ladder cap of claim 1 wherein the ladder cap material is plastic.
- 16. The ladder cap of claim 1, further comprising detents disposed at about the open end of the cap, the detents being configured to constrict around the ladder rail received therein.
- 17. The ladder cap of claim 1 wherein the lower rib height is about zero inches.
- 18. A ladder cap for covering an end of a ladder side rail, the ladder cap comprising:a cap having at least two narrow sides, two wide sides, and a top, the narrow sides, wide sides and top defining an open end for fitting over the rail and a closed end, each of the narrow and wide sides being tapered and wider at about the closed end and narrower at about the open end; and a plurality of internal ribs on the two wide sides for engaging the ladder side rail, wherein each of the plurality of internal ribs on the two wide sides comprises an indent portion.
- 19. The ladder cap of claim 18, further comprising detents disposed at about the open end of the cap, the detents being configured to constrict around the ladder rail received therein.
- 20. The ladder cap of claim 18 wherein the indent portions of the plurality of internal ribs on the two wide sides are adjacent the closed end of the cap.
- 21. The ladder cap of claim 20 wherein the indent portions of the plurality of internal ribs on the two wide sides and the closed end define a channel for receiving at least a portion of the rail when the cap is fitted over the end of the rail.
- 22. The ladder cap of claim 18 wherein internal ribs are on the two wide sides and the two narrow sides and wherein the rib height of the internal ribs on the two wide sides is at least ¼ of an inch and the rib height of the internal ribs on the two narrow sides is at least ⅜ of an inch in height.
- 23. The ladder cap of claim 18 wherein the plurality of internal ribs on the two wide sides are tapered.
- 24. The ladder cap of claim 18 wherein the rib height of the internal ribs is at least ¼ of an inch.
- 25. A ladder cap for covering an end of a ladder side rail, the ladder cap comprising:a cap having at least two narrow sides, two wide sides, and a top, the narrow sides, wide sides and top defining an open end for fitting over the rail and a closed end, each of the narrow and wide sides being tapered and wider at about the closed end and narrower at about the open end; and a plurality of internal tapered ribs on the two wide sides for engaging the ladder side rail.
- 26. The ladder cap of claim 25, further comprising detents disposed at about the open end of the cap, the detents being configured to constrict around the ladder rail received therein.
- 27. The ladder cap of claim 25 wherein the tapered ribs also include an indent portion adjacent the closed end of the cap.
- 28. The ladder cap of claim 27 wherein the indent portions of the ribs and the closed end define a channel for receiving at least a portion of the rail when the cap is fitted over the end of the rail.
- 29. The ladder cap of claim 27 wherein the internal tapered ribs are on the two narrow sides.
- 30. A ladder cap for covering an end of a ladder side rail, the ladder cap comprising:a cover adapted to fit over the end of the ladder side rail, and defining an open end for receiving the end of the ladder side rail and a closed end, the cap including two narrow sides and two wide sides, each of the narrow and wide sides being tapered and wider at about the closed end and narrower at about the open end; and tapered means, within the cover, for frictionally engaging the end of the ladder side rail when the end of the ladder side rail is received through the open end.
- 31. A ladder cap for covering an end of a ladder side rail, the ladder cap comprising:a cover adapted to fit over the end of the ladder side rail, and defining an open end for receiving the end of the ladder side rail and a closed end, the cap including two narrow sides and two wide sides, each of the narrow and wide sides being tapered and wider at about the closed end and narrower at about the open end; and means, within the cover, for frictionally engaging the end of the ladder side rail when the end of the ladder side rail is received through the open end, and comprising retention means for retaining the cover on the end of the ladder side rail when a sufficient portion of the ladder side rail has been received through the open end.
US Referenced Citations (6)