US-12624594-B2 - Adjustable hinge for a multi-position ladder

US12624594B2US 12624594 B2US12624594 B2US 12624594B2US-12624594-B2

Abstract

An improved adjustable hinge for a multi-position ladder that is positionable in a variety of configurations while being ergonomic to adjust and which is structurally sound, rigid, and easy to adjust, light in weight, and has a long service life. The mating surfaces of the outer hinge plates, inner hinge plates, and inner hinge center spacer are large, contributing to overall hinge rigidity and stability. The size of the lock button and lock bracket are each relatively large, making them ergonomic to operate, while also being large enough to be operable by a gloved human hand. A method of assembling an improved adjustable hinge for a multi-position ladder that is positionable in a variety of configurations.

Inventors

Joseph P. Foley
Dennis D. Simpson
Benjamin P. Williams

Assignees

TRICAM INDUSTRIES, INC.

Dates

Publication Date: 20260512
Application Date: 20230906

Claims (14)

1 . An adjustable hinge for a multi-position ladder, comprising: two outer hinge plates, each outer hinge plate having an outer hinge plate mating surface; two inner hinge plates, each inner hinge plate having an inner hinge plate mating surface, the inner hinge mating surface having an inner hinge mating surface diameter; a center lock pin; a lock sleeve; a lock button having a locked position and an unlocked position and a diameter; a lock bracket having a locked position and an unlocked position, said lock bracket having a pair of locking pins, each locking pin having an equal locking pin radius; two outer hinge outside spacers, each outer hinge outside spacer disposed opposite each outer hinge plate mating surface; two inner hinge outside spacers; an outer hinge center spacer; a lock spring coaxial to and surrounding the lock sleeve and between the lock button and one of the outer hinge plates biasing the lock bracket in the locked position, the lock spring being visible when the lock button is in the locked position; and wherein said outer hinge outside spacers, said outer hinge plates, and said outer hinge center spacer form an outer hinge extension having a width; wherein said inner hinge outside spacers and said inner hinge plates form an inner hinge extension having a width, the inner hinge extension width defined by a perpendicular distance between parallel opposite edges of the inner hinge plates; wherein the inner hinge plate mating surface diameter is a length within a range defined between 170-200% of the inner hinge extension width; wherein the lock button diameter is greater than the inner hinge extension width and the lock button diameter is generally equal to two times the locking pin radius.
2 . The adjustable hinge of claim 1 wherein the diameter of the lock button is at least 110% of the inner hinge extension width.
3 . The adjustable hinge of claim 1 , wherein the radius of the lock bracket is at least 75% of the inner hinge extension width.
4 . The adjustable hinge of claim 1 wherein the outer hinge plates and inner hinge plate are manufactured from an alloy of aluminum.
5 . The adjustable hinge of claim 1 wherein the outer hinge plates and inner hinge plates are manufactured from an alloy of steel.
6 . The adjustable hinge of claim 1 further comprising an inner hinge center spacer, wherein the inner hinge center spacer is manufactured from a synthetic polymer.
7 . The adjustable hinge of claim 6 wherein the inner hinge center spacer is manufactured from polyoxymethylene.
8 . The adjustable hinge of claim 1 wherein the outer hinge outside spacers and inner hinge outside spacers are manufactured from a synthetic polymer.
9 . The adjustable hinge of claim 1 wherein the outer hinge outside spacers and inner hinge outside spacers are manufactured from polyoxymethylene.
10 . The adjustable hinge of claim 1 wherein the outer hinge outside spacers and inner hinge outside spacers are manufactured from an alloy of aluminum.
11 . The adjustable hinge of claim 1 wherein the outer hinge outside spacers and inner hinge outside spacers are manufactured from an alloy of steel.
12 . A multi-position ladder, comprising: two adjustable hinges, each of two said hinges comprising: two outer hinge plates, each outer hinge plate having an outer hinge plate mating surface; two inner hinge plates, each said inner hinge plate having an inner hinge plate mating surface, the inner hinge plate mating surface having an inner hinge plate mating surface diameter; a center lock pin; a lock sleeve; a lock button having a locked position and an unlocked position and having a lock button diameter; a lock bracket having a locked position and an unlocked position, said lock bracket having a locking pin, the locking pin having a locking pin radius; two outer hinge outside spacers, each outer hinge outside spacer disposed opposite each of said two outer hinge plate mating surfaces; an inner hinge center spacer; two inner hinge outside spacers; an outer hinge center spacer; a lock spring coaxial to and surrounding the lock sleeve and between the lock button and one of the outer hinge plates biasing the lock bracket in the locked position, the lock spring being visible when the lock button is in the locked position; and wherein said outer hinge outside spacers, said outer hinge plates, and said outer hinge center spacer form an outer hinge extension having a width; and wherein said inner hinge outside spacers and said inner hinge plates form an inner hinge extension having a width, the inner hinge extension width defined by a perpendicular distance between parallel opposite edges of the inner hinge plates; wherein each inner hinge plate mating surface diameter is a length of 170-200% of the inner hinge extension width; wherein the lock button diameter is greater than the inner hinge extension width and the lock button diameter is generally equal to two times the locking pin radius; and a multi-position ladder rail matably attached to each inner hinge extension; and a multi-position ladder rail matably attached to each outer hinge extension.
13 . The multi-position ladder of claim 12 wherein the multi-position ladder is primarily manufactured from aluminum.
14 . The multi-position ladder of claim 12 wherein the multi-position ladder is primarily manufactured from fiberglass.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of application Ser. No. 15/464,807, filed Mar. 21, 2017, which claims the benefit of application Ser. No. 29/589,674, filed Jan. 4, 2017, now U.S. Pat. No. D860,476, each of which is hereby fully incorporated herein by reference. FIELD OF THE INVENTION The present invention relates generally to a ladder. More particularly, the present invention relates to an improved adjustable hinge for an ergonomic, multi-position ladder that is structurally sound, rigid, light in weight, and easy to adjust. BACKGROUND OF THE INVENTION Portable ladders are commonly used for a variety of applications, with several different styles being widely used. The two best known designs are extension ladders, which must be leaned against a vertical surface for support, and step ladders, which are free standing. For some time it has been known that constructing ladders with two sections that are slidably mounted with respect to each other enables the overall length of the extension ladder to be varied depending upon the desired use of the extension ladder. This feature is particularly useful for transporting the ladder to a desired use location. However conventional extension ladders do not have the ability to stand up without being leaned against another object. In certain circumstances it is not possible to lean the extension ladder against other objects. To overcome this shortcoming, Kummerlin et al., U.S. Pat. No. 3,692,143, pivotally attaches two extension ladders together. This ladder retained the benefits of being able to adjust the height of the ladder while adding the benefit that the ladder could remain erect without leaning against other objects. Multi-position ladders have become very popular in recent years because of their versatility, and are being used for a variety of applications by members of the construction trade, maintenance personnel, and homeowners, among others. Many improvements have been made to the design of multi-position ladders. Simpson et al., U.S. Pat. No. 6,857,503, is directed to a multi-position ladder that is versatile, light weight, and relatively low in cost. A common element of most multi-purpose ladders is the hinge assembly, which enables the adjustability of the ladder's position while also contributing to its stability while in a working position. Accordingly, many improvements have been made to the design of the hinge components of multi-position ladders. U.S. Pat. Nos. 4,407,045 and 4,566,150, to Boothe, are both directed to a hinge for an articulating ladder. The hinge includes two hinge plates that are pivotally attached with a central hub. Pivoting of the hinge plates is controlled with a locking handle that extends through apertures in the hinge plates. The locking handle is biased to a locking position where the legs on the locking handle extend into the hinge plate apertures. Most hinges on adjustable ladders generally include a locking handle that secures the sections of the ladder in place when in use, and a spring-loaded actuator that is used by the operator to disengage the locking handle in order to adjust the position of the hinge, and accordingly the position of the ladder. Lee et al., U.S. Pat. No. 6,711,780, is directed at a concealed spring within the locking mechanism to prevent the hands or gloves of an operator from becoming jammed in the spring when the press part is pressed. An alternative to the press-part design of adjustable ladder hinges utilizes a locking cam. Sheng, U.S. Pat. No. 5,620,272, is directed toward hinge design that utilizes a locking rod and a coupling disc containing a plurality of holes in various positions to enable hinge position adjustment. Purkapile, U.S. Pat. No. 4,773,503, is directed at a hinge that employs circular teeth on mating faces of the adjustable hinge and a cam lock, offering the ability for the hinge to assume a greater number of adjustable positions than that available with the aforementioned design. When selecting a multi-purpose ladder for use or purchase, users may consider many factors including product cost, ladder weight, ease of use, and safety. In particular, the ease of use for a multi-position ladder pertains to the ease of adjustability for its hinges, and the speed at which the hinges can be adjusted for repositioning. For users of multi-position ladders in the construction and crafts trades, where the multi-position is used extensively in their work, it may be cumbersome to operate the adjustment features on popular hinge styles that require pushing inward on the press part from the outside of the ladder on each side of to disengage the locking handle, particularly when the ladder is being used in a confined space. The relatively small size of the press part is not very ergonomic and comfortable to operate, especially when this motion may be repeated numerous times by an operator during the work day. Also, while it may be possible to pull inwar