COMBINATION LADDER AND HINGE MECHANISM
A combination ladder with a hinge mechanism that utilizes a single latch bar to activate a pair of hinges to allow the ladder to lock into folded, A-frame, and extension ladder positions. The latch mechanism and hinge are located adjacent to the convertible ladder top cap to maximize the ladder length when in the extension position.
1 . A combination ladder comprising:
a pair of front rails spanned by a plurality of steps;
a pair of rear rails spanned by a plurality of rungs;
a hinge mechanism for rotating the pair of front rails in relation to the pair of rear rails and locking the rails in a folded orientation, an A-frame orientation, or an extension orientation, the hinge mechanism comprising:
a latch bar;
a pair of hinges, each hinge pivotally connected a respective front rail to a respective rear rail, each hinge comprising:
a front hinge plate;
a rear hinge plate; and
a latch bar guide positioned within its respective front rail;
wherein each rear hinge plate comprises:
a folded notch;
an A-frame notch; and
an extension notch.
2 . The combination ladder of claim 1 wherein each latch bar guide comprises a top edge and a latch bar guide slot.
3 . The combination ladder of claim 2 wherein each latch bar guide slot and latch guide top edge define a latch bar guide slot angle between 5-30 degrees.
4 . The combination ladder of claim 3 wherein the latch bar guide slot angle is 17.5 degrees.
5 . The combination ladder of claim 2 wherein the latch mechanism further comprises:
a latch spring;
a latch spring guide; and
a latch spring coupler, the latch spring coupler linking the latch spring to the latch bar.
6 . The combination ladder of claim 5 wherein the latch spring coupler comprises a guide channel and the latch spring guide comprises a shaft and wherein the latch spring guide shaft is at least partially disposed within the latch spring coupler guide channel.
7 . The combination ladder of claim 6 wherein the latch bar guide slot comprises a rear face that defines a guide slot depth and the latch spring biases the latch bar away from the rear face.
8 . The combination ladder of claim 7 wherein the latch bar has a latch bar depth and the latch bar guide slot depth is at least twice the latch bar depth.
9 . The combination ladder of claim 8 wherein the latch bar guide includes a visual indicator that the latch bar is completely inserted into the A-frame notch or the extension notch.
10 . The combination ladder of claim 8 wherein the latch bar comprises a latch bar grip.
11 . The combination ladder of claim 10 wherein the latch bar is moved by directly pulling on the latch bar or latch bar grip.
12 . The combination ladder of claim 1 further comprising a top cap wherein the hinge mechanism is adjacent to the top cap.
13 . A combination ladder comprising:
a pair of front rails spanned by a plurality of steps;
a pair of rear rails spanned by a plurality of rungs;
a hinge mechanism for rotating the pair of front rails in relation to the pair of rear rails and locking the rails in a folded orientation, an A-frame orientation, or an extension orientation, the hinge mechanism comprising:
a latch bar having a latch bar grip;
a pair of hinges, each hinge pivotally connected a respective front rail to a respective rear rail, each hinge comprising a latch bar guide positioned within its respective front rail, each latch bar guide comprising:
a latch spring;
a latch spring guide;
a latch spring coupler, the latch spring coupler linking the latch spring to the latch bar; and
a latch bar guide slot.
14 . The combination ladder of claim 13 wherein the latch spring coupler comprises a guide channel and the latch spring guide comprises a shaft and wherein the latch spring guide shaft is at least partially disposed within the latch spring coupler guide channel.
15 . The combination ladder of claim 14 wherein the latch bar guide slot comprises a rear face that defines a guide slot depth and the latch spring biases the latch bar away from the rear face.
16 . The combination ladder of claim 15 wherein the latch bar is moved by directly pulling on the latch bar or latch bar grip.
17 . The combination ladder of claim 16 wherein the hinge mechanism is adjacent to the top cap.
18 . A hinge mechanism for a combination ladder comprising:
a latch bar;
a pair of hinges functionally coupled by the latch bar, each hinge comprising:
a front hinge plate;
a rear hinge plate; and
a latch bar guide having a latch bar guide slot;
wherein each rear hinge plate comprises:
a folded notch;
an A-frame notch; and
an extension notch;
wherein the latch bar is moveable within the latch bar guide slot from a position within one of the folded notch, A-frame notch, or folded notch to outside of any of the notches.
19 . The hinge mechanism for a combination ladder of claim 18 wherein each latch bar guide further comprises:
a latch spring;
a latch spring guide;
a latch spring coupler, the latch spring coupler linking the latch spring to the latch bar.
20 . The hinge mechanism for a combination ladder of claim 19 wherein the latch spring coupler comprises a guide channel and the latch spring guide comprises a shaft and wherein the latch spring guide shaft is at least partially disposed within the latch spring coupler guide channel.