Patent ID: 12241309

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings wherein like reference numerals refer to similar or identical parts throughout the several views, and more specifically toFIGS.1and2thereof, there is shown a stepladder100. The stepladder100comprises a front section102having a first front leg1aand a second front leg1b. The stepladder100comprises a step3attached to the first front leg1aand the second front leg1b. The stepladder100comprises a latch8engaged with the step3. The stepladder100comprises a rear section104having a first rear leg2aand a second rear leg2band a cross bar6attached to the first rear leg2aand the second rear leg2b. The rear section104is pivotably attached to the front section102. The rear section104has a first stud13awhich extends from the first rear leg2atoward the second rear leg2band separate and apart and not in contact with the second rear leg2band not in contact with the cross bar6. The latch8is engaged with and latched to the first stud13ato define an engaged position where the first front leg1aand the first rear leg2aare in an open position and form an inverted v shape and are prevented from folding together, and the latch8when pulled up from the engaged position, disengages from the first stud13aand allows the front section102and rear section104to fold together into a closed position where the first rear leg2aand the first front leg1aare in parallel.

The latch8may have a first latch end10athat engages with the first stud13aand a second latch end10bthat engages with a second stud13bwhen the latch8is in the engaged position, as shown inFIGS.3and5. The rear section104may have a second stud13bwhich extends from the second rear leg2btoward the first rear leg2aand is separate and apart and not in contact with the first rear leg2aand the first stud13aand not in contact with the cross bar6. The latch8may include a latch bar9connected to the first latch end10aand the second latch end10bwhich causes movement of the first and second latch ends10a,10bto occur in unison. The latch bar9may be disposed below the step3when the latch8is in the engaged position. The latch8may include a restoring mechanism which moves the first and second latch end10a,10bwhich causes movement of the first and second latch ends10a,10bto occur in unison. The latch bar9may be disposed below the step3when the latch8is in the engaged position. The latch8may include a restoring mechanism which moves the first and second latch ends10a,10binto engagement with the first and second studs13a,13b, respectively, from a disengaged position of the latch8when the first and second latch ends10a,10bdo not engage the first and second studs13a,13b, respectively. The restoring mechanism may include a first spring11awhich engages with the first latch end10aand a second spring11bwhich engages with the second latch end10b.

The step3may include a first side106, a second side108, a front110and a rear112, and including a first step link5aattached to the first rear leg2aand the first side106of the step3; and a second step link5battached to the second rear leg2band the second side108of the step3. The crossbar may support the rear112of the step3when the latch8is in an engaged position. Each latch end may have a cam portion16, as shown inFIG.8. As the cam portion16contacts the respective stud when the rear112of the step3is moved downward, the cam portion16moves so that a hook portion14of the latch end, shown inFIG.6, bypasses the respective stud until the hook portion14clears the respective stud, at which point the respective spring moves the hook portion14to engage the respective stud and place the latch8into the engaged position.

The step3may include a first stop12adisposed on the first side106of the step3and a second stop12bdisposed on the second side108of the step3, as shown inFIG.3, which prevent the latch8from rotating beyond a desired position. Each hook portion14of each latch8may be disposed beneath the respective stud and held there by torque supplied by the respective spring. The first stud13amay not support the step3. The stepladder100may include a latch pivot20which extends through a latch end and a boss120on the step3and about which the coil section of the spring is positioned.

The present invention pertains to a method of positioning a stepladder100. The method comprises the steps of pivoting a front section102having a first front leg1aand a second front leg1brelative to a rear section104having a first rear leg2aand a second rear leg2band a cross bar6attached to the first rear leg2aand the second rear leg2bto an open position. The rear section104has a first stud13awhich extends from the first rear leg2atoward the second rear leg2band is separate and apart and not in contact with the second rear leg2band not in contact with the cross bar6. There is the step of engaging a latch8to the first stud13ato define an engaged position where the first front leg1aand the first rear leg2aare in an open position and form an inverted v shape and are prevented from folding together. The latch8is engaged with a step3and the step3is attached to the first front leg1aand the second front leg1b. There is the step of pulling up on the latch8from the engaged position to disengage the latch8from the first stud13a. There is the step of folding the front section102and rear section104together into a closed position where the first rear leg2aand the first front leg1aare in parallel.

There may be the steps of contacting the first stud13awith a cam portion16of a first latch end10aof the latch8; moving the cam portion16so that a hook portion14of the first latch end10abypasses the first stud13a; and moving the hook portion14clockwise to engage the first stud13aand place the latch8into the engaged position after the hook portion14clears the first stud13a.

In the operation of the invention, the following describes the design and operation of the disclosed latch8as applied to the simplified single-step folding stepladder seen inFIGS.1,2, and3. It should be understood that this latch8design could also be applied to folding stepladders having multiple steps.

FIG.1shows the stepladder in the open position. Front legs1are hinged to the rear legs2. A step3is attached to the front legs1by rivets4so that the step3can pivot to a closed position seen inFIG.2. Step links5are pivotally connected to the step3and to the rear legs2. The step links cause the rear legs to move to a position parallel to the front legs when the stepladder is folded.

A cross bar6is rigidly attached to the rear legs2. The cross bar6provides added stiffness to the rear legs and supports the rear112of the step3when in the open position by way of projections7on the underside of the step3which contact the cross bar6. This can be seen inFIG.6.

A symmetric latch8is pivotally attached to the sides of the step3. The latch8consists of a latch bar9and two latch ends10. This is seen inFIG.3. Springs11are symmetrically mounted at both ends of the latch8in such a way as to apply a torque to the latch8. The torque is in a CW direction when seen inFIG.4, which is a view with the rear legs, etc, removed for clarity. Stops12on both sides of the step3(FIGS.3&4) prevent the latch8from rotating CW beyond the position shown inFIG.4.

Additional details of the springs11and their mounting can be seen inFIG.11. In this Figure the rear legs and step link are not shown. The springs11consists of a coiled section17and two ends and is similar to the torsion spring of a common clothes pin. (FIG.12shows the spring in its relaxed state.) The coiled section17is installed concentric with the latch pivot20. The fixed end18is hooked into a hole122in the step3and the moving end19is hooked over the latch end10. By comparingFIG.6andFIG.7it can be seen that when the latch8is moved toward the unlatched position, the fixed end18does not move but the moving end19moves with the latch8and biases the latch back toward the latched position. The latch pivot20is a rivet which extends through a latch end10and a boss120on the step3and about which the coil section17of the spring11is positioned.”

Two studs13(seen inFIGS.2,3, &5) serve to attach the step links5to the rear legs2and provide engagement points for the latch8. InFIG.5the step3has been removed to show one stud13more clearly. The studs13do not support the step3in any way.

Note,FIGS.6,7,8, &9are phantom views with components shown “wireform”. These views show the right side of the stepladder but it should be understood that the stepladder and all its latch components are symmetric about the center plane.

FIG.6shows the stepladder when fully opened and the latch8in the fully engaged position. The hook14portion of the latch end10is beneath the stud13and held there by the torque supplied by the spring11. In this position the latch positively prevents the stepladder from folding.FIG.10is a closeup of the right side latch components as seen from the rear112when the latch is fully engaged.

FIG.7shows how the latch8is disengaged from the stud13in order to fold the stepladder. The user reaches under the rear112of the step3and lifts up on the latch bar9of the latch8. The latch8will rotate against spring11torque until the latch bar9contacts the underside15of the step3. By that time the hook14portion of the latch end10has disengaged from the stud13. The user can then lift up the rear112of the step3to fold the stepladder. Once the rear112of the step3has risen a short distance the user may allow the latch8to return to the position seen inFIGS.3&4.

To move the stepladder to its open and latched position the user pushes the rear edge of the step3rearward and downward.FIG.8shows the cam16portion of the latch8as it contacts the stud13. Continued downward motion of the rear edge of the step3causes the latch8to rotate CCW (as viewed) so that its hook14portion is able to bypass the stud13as seen inFIG.9. As seen inFIG.6, when the projections7on the step3contact the cross bar6, the latch8returns under spring11torque to its fully engaged position. The user is assured that the latch is engaged by hearing and feeling it snap into its engaged position.

Although the invention has been described in detail in the foregoing embodiments for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be described by the following claims.