Patent Grant
8807277
Not applicable.
Not applicable.
Not applicable.
Not applicable.
1. Field of the Invention
The present invention relates to ladder assemblies. More particularly, the present invention the relates to shoe bracket assemblies that are used at the bottom of the rail of ladder so as to securely position the ladder with respect to an underlying surface.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
Ladders are conventionally utilized to provide a user thereof with improved access to elevated locations that might otherwise be inaccessible. Ladders come in many shapes and sizes, such as straight ladders, straight extension ladders, stepladders, and combination step and extension ladders.
Ladders known as straight ladders or straight extension ladders are ladders that are conventionally positioned against an elevated surface, such as a wall or the edge of a roof, to support the ladder at a desired angle. A user then ascends the ladder to obtain access to an elevated area, such as access to an upper area of the wall or access to the roof. Straight ladders and straight extension ladders are referred to as being “straight” because their rails are typically straight and generally parallel to one another throughout the length of the ladder. A pair of feet or pads, one being coupled to the bottom of each rail, are conventionally used to engage the ground, a floor or some other supporting surface.
A ladder foot commonly comprises a U-shaped shoe pivotally coupled by a pin to the bottom of a rail of a ladder in a manner whereby the shoe is angularly adjustable between flat, toe-down and intermediate positions. In the flat position, the bottom of the shoe rests on the ground or other footing to provide maximum adhesion to smooth flat surfaces, such as asphalt, wood, concrete, etc. In the toe-down position, the shoe is tilted to have its front part contact the ground and serve as a pick-like device to provide maximum penetration and holding power on ice or hard, soft, sandy, or frozen earth.
In the past, it has been a common practice for the shoe of a ladder foot to be coupled to a rail of the ladder by a pin-and-slot coupling wherein the pin is passed laterally through a hole in the rail to be translationally fixed in relation thereto, and wherein the pin has opposite ends projecting out from laterally opposite sides of the ladder rail, and those opposite ends of the pin are received in two slots respectively formed in the two sidewalls of the U-shaped shoe.
A ladder foot of such construction has, however, a number of disadvantages for use in present day ladders. In order to provide ladders that are inexpensive, light in weight, and durable, the rails thereof are often in the form of lengths of fiberglass of U-shape in cross section so as to have a central, longitudinal elongated relatively thin web and, also, two longitudinally elongated side flanges projecting out in the same direction from the opposite sides of the web. Such rails do not lend themselves readily to a pin-and-slot coupling of a shoe to the rail wherein the two slots are in the shoe and the pin passes through a hole in the web of the rail to be translationally fixed in relation thereto. That is so, because, in view of the thinness of the fiberglass web, it would be difficult to maintain the bolt fixed in its normal alignment to the web and, because of the web thinness and the lack of mechanical strength of the fiberglass web, the transmission of half the weight of the ladder and its occupant from the web to the pin would create undue stresses in the region of the web near the pin.
In another consideration, the provision of pivotally mounting the shoe to the ladder rail by a pin-and-slot coupling wherein slots are formed in the sidewalls of the shoe has the disadvantage that the slots take up substantial space in the shoe's sidewalls in which the slots must be surrounded with a sufficient thickness of sidewall material throughout the length of the slot to withstand the mechanical strain imposed on each sidewall when the shoe is bearing substantial weights. This means, however, that each of the sidewalls of the shoe must be larger in dimension than is really necessary.
In the past, various patent have issued relating to ladder shoes and ladder shoe bracket assemblies. An early patent is that of U.S. Pat. No. 2,449,609, issued on Sep. 21, 1948 to O. A. Linder. This patent shows a rectangular plate secured of the lower leg of the ladder. Vertical flanges border the plate. A U-shaped member is slidably mounted within the flanges. A resilient means retains the sliding member upwardly retracted between the flanges. A bracket is secured to the sliding member. A T-shaped member is carried by the bracket such that the leg of the T is in an outwardly extended position. A cylindrical tube is secured to the sliding member. A ground engaging foot is resiliently carried within the tube. The T-leg is adapted to be lowered and locked against the resilient means to position the foot in an extended ground-engaging position.
U.S. Pat. No. 2,691,479, issued on Oct. 12, 1954 to J. E. Sharp, describes a ladder shoe. This ladder shoe is adapted to be pivotally and shiftably attached to the base of ladder rail upon a bolt projecting through the ladder rail above its base edge. The bottom carries an anti-slip tread on its underside and a spike at one end thereof. A pair of parallel side walls upstanding from the bottom and spaced apart sufficiently receive the ladder rail base therebetween. Relatively aligned apertures in the side walls allow the attaching bolt to extend therethrough. The apertures are elongated to permit shifting of the shoe upon the bolt.
U.S. Pat. No. 3,456,757, issued on Jul. 22, 1969 to B. S. Sain, describes a ladder stabilizer boot. The ladder legs are securely deposited in adjustable sleeve or channel. The sleeve is swivelly mounted on the boot along various angles. The boot has a base formed with a horizontal flange which is provided with ground-gripping means including holes through which anchoring pins may be driven. The sleeve is adapted to receive the ladder leg and is provided with bolts to penetrate holes in the ladder legs so as to secure it firmly to the sleeve.
U.S. Pat. No. 4,415,062, issued on Nov. 15, 1983 to J. L. Shaw, discloses a ladder foot having a bracket attached at its upper end to a ladder rail and includes a stud extending downwardly from this end. A shoe has a central sole plate and a pair of upper plates extending from the sole plate to straddle opposite sides of the bracket. A pin is fixedly secured with the upper plates and passes from one to the other through the bracket adjacent the front side of the stud. The downward extent of the stud includes an upper range within which the stud fits between the pin and sole plate in such manner that the shoe is locked in toe-down position. There are portions integrally joined with the stud so as to serve as stops for the pin.
U.S. Pat. No. 5,154,255, issued on Oct. 13, 1992 to Kiska et al., teaches a ladder shoe and method of use. The ladder shoe has a shoe body having a first side plate, a second side plate and a base. The first side plate and the second side plate are attached to the base. The side plates include curved slots through which a fastener is disposed and which movably connects the ladder shoe to the end of the side rail of the ladder. This allows the ladder shoe to move between a first position where the base is at a first angle with respect to the side rail and a second position where the base is at a second angle with respect to the side rail. Each slot has a notch in which the fastener catches causing the shoe to be maintained in an intermediate position until the shoe body is desired to be placed into another position. The base has a bottom which provides a slip-resistant surface for engaging the shoe body to essentially flat surfaces when the shoe body is in the first position.
U.S. Pat. No. 5,370,203, issued on Dec. 6, 1994 to S. A. Kiska, shows a ladder shoe spur plate. The ladder shoe has a base. This base has an elongate portion having a first side and a second side, a first edge and a second edge, and a top face and a bottom face. The top face is attached to the ladder rail attachment portion. The base has a foot pad. The base includes of a blade portion extending from the first edge. The base has a first flange portion extending from the bottom face and integrally connected thereto. There is also a second flange portion extending from the bottom face and integrally connected thereto. The base further includes a third flange portion extending from the bottom face and integrally connected thereto. A fourth flange portion extends from the bottom face and is also integrally connected thereto. The first, second, third and fourth flange portions form a pocket in which the footpad is held along the bottom face and sides of the footpad.
It is an object of the present invention to provide a shoe bracket assembly that can be preassembled prior to attachment to the ladder.
It is another object of the present invention to provide a shoe bracket assembly that is securely retained at the end of the ladder rail.
It is another object of the present invention to provide a shoe bracket assembly that is easy to repair or replace.
It is another object of the present invention to provide a shoe bracket assembly that provides stronger support to the fragile bottom ends of the ladder rails.
It is still a further object of the present invention to provide a shoe bracket assembly that allows the ladder rail to be securely positioned upon an underlying surface.
It is another object of the present invention to provide a shoe bracket assembly that properly guides the end of the rail into a properly seated position.
It is still a further object of the present invention to provide a shoe bracket assembly that simplifies assembly of the shoe bracket of the ladder.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.
The present invention is a shoe bracket assembly for attachment to a bottom of a rail of a ladder. The shoe bracket assembly includes a channel member having a side wall, a first end wall and second end wall. The first end wall and the second end wall extend in generally transverse relationship to the side wall. The channel member has a hole formed therethrough. A bracket is affixed to a side wall of the channel member and positioned between end walls of the channel member. The bracket has a central portion having a first flange and a second flange extending outwardly therefrom. The first flange and the second flange are affixed to the side wall of the channel member. The bracket has a third flange and a fourth flange extending outwardly from the central portion. The third flange and the fourth flange are positioned in spaced relationship to the side wall so as to define a space therebetween. The third and fourth flanges extend in a plane and in parallel relationship to a plane of the first and second flanges. The central portion has a hole formed therethrough in axial alignment with the hole of the channel member.
The central portion of the bracket has a shoulder formed therein at a location adjacent the first and second flanges. The first and second flanges are riveted to the side wall of the channel member. The third and fourth flanges each have a hole formed therethrough.
The shoe bracket assembly of the present invention also has a foot having a bottom surface. The foot has a first surface and a second surface extending upwardly from the bottom surface. Each of the first and second surfaces have an opening formed therein. The first surface is positioned adjacent a side wall of the channel member. The second surface is positioned adjacent the central portion of the bracket. An axle extends through the openings of the first and second surfaces and through the hole in the side walls of the channel member and the hole in the central portion of the bracket. Each of the first and second openings comprise an elongated slot extending along the respective surfaces of the foot. In the preferred embodiment of the present invention, axle is a bolt having a head bearing against one of the first and second surfaces and a nut bearing against the other of the first and second surfaces. The elongated slot has a longitudinal axis extending at a non-transverse acute angle with respect to the bottom surface. The foot can have a polymeric or elastomeric gripping surface attached to the bottom of the foot.
When the shoe bracket assembly is attached to the rail of ladder, the channel member will have the first end wall positioned adjacent to the first end side of the ladder. The second end wall of the channel will be positioned adjacent to the second end side of the rail. The side wall of the channel member is positioned adjacent to the central side of the rail. The bottom edge of the rail will extend in the space between third and fourth flanges and the side wall of the channel member. The bottom edge of the rail will rest on a shoulder formed in the bracket adjacent to the first and second flanges.
The side wall of the channel member includes a first hole and a second hole formed therein. The third and fourth flanges each have a hole formed therein. The first and second holes of the channel member are aligned respectively with the holes of the third and fourth flanges. A first fixing member extends through the central side of the rail and through the first hole of the channel member and through the hole of the third flange. A second fixing member extends through the central side of the rail and through the second hole of the channel member and through the hole of the fourth flange. The side wall of the channel member is riveted to the central side of the rail. The bottom edge of the rail bears against the shoulder of the bracket. The hole of the central portion of the bracket and the hole of the channel member positioned below and in spaced relation to the bottom edge of the rail.
The foregoing Section is intended to describe, in generality, the preferred embodiment of the present invention. It is understood that modifications to this preferred embodiment can be made within the scope of the present invention. As such, this Section should not to be construed, in any way, as limiting of the scope of the present invention. The present invention should only be limited by the following claims and their legal equivalents.
As can be seen in
The bracket 14 is affixed to the side wall 16 of the channel member 12. The bracket 14 is positioned between the end wall 18 and the end wall 20 of the channel member 12. The bracket 14 has a central portion 22 having a first flange 24 and a second flange 26 extending outwardly therefrom. The first flange 24 and the second flange 26 are affixed by suitable rivets to the side wall 16 of the channel member 12. The bracket 14 also has a third flange 28 and fourth flange 30 extending outwardly of the central portion 22. The third flange 28 and the fourth flange 30 are positioned in spaced relationship to the side wall 16 of the channel member 12 so as to define a space therebetween. As such, the bottom edge of the ladder rail can reside in the space between the third flange 28 and the fourth flange 30 and the side wall 16. The third flange 28 and the fourth flange 30 extend in a plane and in generally parallel relationship to a plane in which the first flange 24 and the second flange 26 extend. It can be seen that there is a hole 32 formed in the central portion 22. The side 16 of the channel member 12 has a hole 34 formed therein. Hole 32 will be axially aligned with the hole 34. As such, the holes 32 and 34 can provide an area through which an axle can extend for the attachment of a foot to the shoe bracket assembly 10.
The bracket 14 has central portion 22 arranged in spaced relationship to the side wall 16. The hole 32 is formed through the central portion 22. Similarly, the hole 34 is formed through the side wall 16. Holes 32 and 34 are illustrated as in axial alignment. As such, holes 32 and 34 are suitably arranged so as to receive the axle of the foot therein.
In
The shoe bracket assembly 10 is illustrated as having the channel member 12 secured around the bottom end of the ladder rail 50. The channel member 12 has its first end wall 18 positioned against the first end side 52 of the rail 50. The second end wall 20 of the channel member 12 is secured against the outer surface of the second end side 54 of the ladder rail 50. The side wall 16 will be positioned against the outer surface of the central side 56 of the ladder rail 50.
In
As can be seen in
In
Upon assembly, the shoe bracket assembly 10, along with the foot 62 will be properly secured to the bottom of the rail 50 of the ladder.
The present invention achieves significant advantages over the prior art. Fundamentally, since no modification is necessary in the bottom of the ladder rail, the structural integrity of the bottom end of the ladder rail is maintained. Assembly is simplified since it is only necessary to insert the assembled bracket assembly onto the lower end of the ladder rail. If repair is necessary, this bracket assembly can be easily removed by separating the rivets from the structures of the ladder and from the structures of the bracket assembly. The shoe can be easily and strongly attached by a bolt. The proper positioning of the end edge of the ladder rail is assured because of the placement of the shoulder within the bracket. Additionally, the structural integrity of the end of the ladder rail is enhanced because of its sandwiched configuration between the strong structures associated with the bracket and the channel member. The placement of the end edge of the ladder rail a sufficient distance above the foot further avoids any potential damaging contact between the foot and the end edge of the ladder rail.
The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction can 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.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2449609 | Linder | Sep 1948 | A |
| 2691479 | Sharp | Oct 1954 | A |
| 3456757 | Sain | Jul 1969 | A |
| 4415062 | Shaw | Nov 1983 | A |
| 5154255 | Kiska et al. | Oct 1992 | A |
| 5370203 | Kiska | Dec 1994 | A |
| 5791439 | Plotner et al. | Aug 1998 | A |
| 7516817 | Pate et al. | Apr 2009 | B2 |
| 7837010 | Astor | Nov 2010 | B2 |
