US2839233A - Step ladder - Google Patents

Description

June 17, 1958 R. c. MOKINNIE 2,839,233

STEP LADDER Filed.June 22, 19 56 INVENTOR.

ATTORNEYS United States atent O STEP LADDER Roxton C. McKinnie, Los Angeles, Calif.

Application June 22, 1956, Serial No. 593,090

1 Claim. (Cl. 228-29) This invention relates to step ladders and more particularly, to an improved portable step ladder and pail shelf.

Most conventional step ladders used today comprise a pair of front and rear legs secured together at their upper ends for scissoring movement from an opened to a closed position for convenient storage. To provide stability when the ladder is in open position, a spreader arrangement, usually in the form of a pair of pivoted links, extends between the front and rear legs to limit the angle of divergence of the legs. In folding these ladders for storage, it is conventional practice to crook the pivoted links and then scissor the front and rear legs together.

Many of the above types of step ladders are also provided with a pail shelf in the form of a fiat board arranged to extend in a horizontal position at a convenient spacing below the top step of the ladder. In ladders of this type, it is usually necessary to first fold the shelf to a closed position, and then actuate the spreader means when the ladder is to be stored. In some instances, it has been proposed to employ part of the pail shelf structure itself as a spreader means for securing the front and rear legs in a desired open position whereby folding away of the pail shelf will simultaneously effect scissoring together of the front and rear legs for storing the ladder. In such arrangements, however, employing the pail shelf as a spreader support will not provide sufficient stability inasmuch as the pail shelf and thus the spreader portion must be located close to the top of the ladder. If the pail shelf is lowered in order that a portion of it may 'be employed simultaneously as a spreader to overcome this stability problem, then the shelf proper is usually too far below the top step of the ladder for convenient use.

Bearing the above in mind, it is a primary object of the present invention to provide an improved pail shelf and step ladder combination which may be readily folded away by a single manual operation in which both the pail shelf and front and rear legs are simultaneously moved to their folded or closed position.

More particularly, it is an object of the invention to provide a step ladder of the above type having an improved degree of stability over conventional type ladders in both the pail shelf structure and the spreader arrangement.

These and other objects and advantages of the present invention are attained by providing a step ladder incorporating a pail shelf and a spreader means. In accordance with the invention the pail shelf is pivoted between the rear legs and includes a shelf support means extend ing between the rear legs towards the front legs. The extreme ends of the support means terminate under one of the front steps. The shelf is arranged to swing between the rear legs from a substantially horizontal position towards a vertical position whereby the shelf support means in engagement with the underside of one of the steps is free to swing downwardly away from the step while the shelf swings upwardly during the folding 2,83%,233 Patented June 17, 1 953 operation. On the other hand, when any weight is placed on the pail shelf, the shelf is prevented from moving in a downward direction by the engagement of the shelf. support means against the bottom of the opposing step.

A spreader means is also employed between the front and rear legs substantially below the pail shelf at a position where proper stability will be attained. In accordance with a primary feature of the invention, a pail shelf lever in the form of a rigid bar is pivoted at one end to the pail shelf, forward of the point where the shelf support is pivoted to the rear legs and extends downwardly to a pivot point disposed intermediate one of the links of the spreader means. The arrangement is such, that upon folding of the pail shelf from its horizontal position towards a vertical position, suitable forces are transmitted through the shelf lever to the spreader means to crook the same and thus fold the front and rear legs together whereby a single manual movement will effect folding away of both the pail shelf and the legs. A1- tern-atively, the spreader links may be initially crooked and the legs scissored together in a conventional manner whereby the shelf lever operates automatically to simultaneously fold the pail shelf to its closed position. By suitable dimensioning of the shelf lever means, the spreader arrangement may be properly positioned between the top and bottom of the front and rear legs so that reliable stability of the ladder is attained in open position.

A better understanding of the invention will be had by referring to theaccompanying drawings, in which:

Figure 1 is a perspective view of one embodiment of the step ladder of this invention;

Figure 2 is a side elevational view of the ladder in open position;

Figure 3 is a view similar to Figure 2 showing the lad der in partially folded position; and,

Figure 4 illustrates the ladder in completely folded position.

Referring to Figure 1, there is shown a step ladder comprising a pair of front legs 10 and 11 and pair of rear legs 12 and 13. The front and rear legs are secured together at their upper ends to the underside of a top step 14 in a manner such that they may be scissored together to move from an open to a closed position. The front legs 10 and 11 serve to support a plurality of steps indicated at 15, 16, 17 and 18.

The rear legs 12 and 13 support a pail shelf 19 including rearwardly extending shelf support members 29 and 21. Intermediate the far ends of the supports 20 and 21 there is provided a pivot rod 22 passing through the members and the rear legs 12 and 13 as at 23 and 24 whereby the pail shelf 19 may be pivoted from a horizontal position towards a vertical position by arcuate swinging movement about the pivot rod 22. As shown in Figure 1, when the pail shelf 19 is in the open operative position, it is supported in a substantially horizontal plane parallel to the top step 14, the rearwardly extending shelf supports 20 and 21 passing under the step 15 between the front legs 10 and 11.

Disposed at a suitable distance below the pail shelf is a spreader means comprising links 25 and 26 pivoted to gether at 27 and to the front leg 10 and rear leg 12 as at 28 and 29 respectively. Similarly, a pair of links 30 and 31 pivoted at 32, extend between the front leg 11 and rear leg 13 and are pivoted thereto as at 33 and 34. The pivoted links 25, 26, 39 and 31 are dimensioned such that when the front and rear legs are spread at a stable angle whereby the steps 15, 16, 17 and '18 are substantially parallel with the floor, the respective links extend substantially in a straight line between the legs.

As shown in Figure 1, there is also provided on the 7 step ladder a shelf lever comprising a rigid member 35 tween the shelf support 21 and spreader 31 on the opposite side of the ladder.

Referring now to Figure 2, the various components described in Figure l are shown in the positions they assume when the ladder is in open operative position- It will.

be evident that any weight placed 'on the pail shelf 19 will tend to rotate the shelf in a clockwise direction about the pivot point 23 whereby the rear ends of the shelf supports such as the support 20 will be in pressing upward engagement with the step 15. Arcuatemovement of the shelf 19 in a clockwise direction down from the horizontal position shown in Figure 2 is thereby checked. Such weight on the shelf 19 will also be transmitted through the shelf lever 35 to the spreaderlink 26 insuring that'the links 25 and 26 will not become accidentally crooked to the position shown in Figure 3. .Because of the proper length dimensioning of the shelf lever 35, the spreader links 25 and 26 may be spaced a suflicient distance below the shelf to insure stability between the front and rear legs 10 and 12.

In order to fold away the ladder of Figure 2, either the shelf 19 may be pivoted in a counterclockwise direction as'indicated in Figure 3 by the arrow, or the spreader links 25 and '26 may be manually crooked to the position shown. In either event, one action simultaneously effects the other through the rigid connecting lever 35whereby a complete arcuate swinging of the shelf 19 in a counterclockwise direction about the pivot 23 will cause the front "and rear legs to scissors together to a final position shown in Figure 4.

In the event the front and rear legs 10 and 12 are simply manually pushed together thereby crooking the spreader links 25 and 26 to a greater degree, such action is transmittedthrough the shelf lever 35 to the shelf portion 19 thereby automatically causing the shelf to rotate in a counterclockwise direction towards a vertical position about the pivot point 23 to its folded position.

' Unfolding of the ladderffrom the position shown in Figure 4 to the position shown in Figure 2'may be readily effected by simply spreading the legs 10 and 12 whereby the reverse actions described previously take place, the'pail shelf 19 beingcaused to swing arcuately in a clockwise direction about the pivot point '23 as the spreader links 25 and 26 move towards alignment.

It will be evident from. the above description, that the present invention provides an improved step ladder having a desired degree of stability and yet capable of being folded or unfolded .in one manual operation effective to fold both the pail shelf and legs simultaneously. In the event'the legs are longer than those illustrated, the spreader means would be located closer to the lower ends of the legs to insure proper stability. For example, the links 25 and 26 could be pivoted adjacent the step 17 and increased in length. Similarly, the length of the shelf lever 35 would be increased to reach from the shelf to the link 26. The folding and unfolding operation would then take place exactly as described previously.-

Other such minor modifications within the scope and spirit of this invention will occur to those skilled in the art. Thestep ladder is, therefore, not .to be thought of as limited to the specific embodiment chosen for illustrative purposes.

What is claimed is:

In a step ladder including a pair of front legs supporting a plurality of steps therebetween and a pair of rear legs secured at their upper ends adjacent said front legs for scissoring movement from an open to a closed posi- 7 tion, and a co-operating pail shelf, the combination comprising: shelf support means secured to said pail shelf and pivoted betweensaid rear legs for arcuate swinging movement of said shelf about a horizontal axis from a substantially horizontal position, when said ladder is open, towards a vertical position as said ladder is closed, said shelf support means extending towards said front legs and terminating'under'one of said steps; spreader means disposed between said front and rear legs below said pail shelf, said spreader-means comprising pivoted link members having their free ends respectively pivoted to said front and rear legs; and shelf lever means pivoted at one end adjacent to said pail shelf at a point horizontally beyond both said front and rear legs so that the point at which said shelf support means is pivoted between said rear legs lies between said one end of said lever means and said one ofsaid steps, said lever means being pivoted at its other endto the one of said pivoted link members pivoted to said rear legs, at an intermediate point thereon, whereby the load upon said pail shelf is transmitted to said spreader means, thereby relieving strain upon said rearlegs at the pivot point of said shelf support'means,

and whereby movement of said pail shelf from a horizontalposition towards a vertical position causes said link members to fold together to close simultaneously the front and rear legs of said ladder.

References Cited in the file of this patent UNITED STATES PATENTS

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