This invention relates generally to ladders and step stools, more specifically to ladders and step stools adapted for indoor use.
Previously, ladders have been made with little concern for basic safety. Standards have now been implemented that require a constraint which prevents the user from accidentally folding a ladder or step stool during use. The constraint must prevent an unintended fold up or collapse of the ladder or step stool. Such an unintended folding up of the ladder or step stool can result from a user running up to a ladder or walking briskly onto the ladder. The sideways force of the user can cause the ladder or step stool to fold or collapse. In other instances, the user may move to one side or the other and the resultant forces could cause the ladder to collapse or prematurely fold. The results can be very devastating. The user may fall and become injured. The items attached to the ladder or step stool may spill or fall. The items being carried by the user may also spill and fall causing further damage.
Several step stools and ladders now are provided with latches or other constraints. Some latches are for locking a bifurcated step into one of two positions. U.S. Pat. No. 4,485,892 teaches a locking mechanism for a platform stool which is used to lock a bifurcated step into one of two positions. U.S. Pat. No. 5,722,507 teaches a locking mechanism for a ladder which is used to lock a step into one of two positions. U.S. Pat. No. 5,762,163 also teaches locking mechanism for a step stool which is used to lock a bifurcated step into one of two positions. Both U.S. Pat. Nos. 5,722,507 and 5,762,163 are assigned to Cosco, Inc. of Columbus, Ind.
Some latches are for prevention of the collapse or premature folding of a ladder or step stool. The locking mechanisms shown are generally difficult to use. The latches are located below a step on the step stool or ladder and are generally not visible to the user. The user may unfold the step stool or ladder which may engage the lock or latch. However, since the latches or locks are hidden from view folding the ladder or step stool back into its collapsed or storage position may be a problem. Since the lock is not visible, users may become frustrated when trying to fold the ladder or step stool. Sometimes users feel the step stool or ladder is broken and resort to brute force to forcibly fold the step stool or ladder. This ruins the ladder or step stool or causes a loss in the structural integrity of the unit.
What is needed is a step stool or ladder that has a latch that prevents premature or an undesirable folding. What is also needed is a latch that is readily visible when the ladder is in use. Also needed is a ladder which is easy to store within the house.
The disclosed ladder or step stool has a first frame member and a second frame member. The second frame member folds to a position within the confines of the first frame member to provide a thin, easily stored ladder for use within a household. The first frame member includes a safety hoop at which the user can easily grab while on the step or rung of the ladder or step stool. The frame also includes a cross member which spans a portion of one of the frame members. The ladder or step stool has one or more steps. At least one of the steps is supported primarily by the cross member in its unfolded position in which a user can ascend on the steps of the stool or ladder. One or more other steps may be attached to step which is primarily supported by the cross member.
The step that is primarily supported by the cross member includes a latch that has a first curved end which engages the cross member to prevent the step primarily supported by the cross member from disengaging the cross member. The latch has a curved end which engages the cross member. The other end of the latch extends through an opening in the step so that the latch is accessible and visible to the user. The end passing through the opening in the step is provided with a knob that gives further visual cues to the user. The knob also maintains the latch in its position in the opening in the step. The midsection of the latch includes a portion which is bent out of the main plane of the latch. The bent portion serves to limit the amount of travel between the knob and the bent portion. The latch rotates on the portion of the latch between the bent portion and travel limiter and the knob attached to the latch.
In use, the latch is spaced so that it will engage the cross member with a normal gravitational force. The curved end slips over the cross member. By pushing down on the knob accessible on the outside of the step, the curved end of the latch disengages the cross member. Advantageously, the latch is visible by the user and the knob is provided with a simple written instruction so that the use of the latch is more intuitive. This prevents the user from becoming frustrated and forcibly trying to close the ladder.
USPTO Backgrounds
USPTO Backgrounds