US2126805A - Stepladder - Google Patents

Description

Aug. 16, 1938.

R. R. PARKISON ET AL STEPLADDER Filed March 17, 1937 2 Sheets-Sheet 1 INVENTOR5. 0 7?. RIIEKI/l/JO/l/ Patented Aug. 16, 1938 UNITED STATES PATENT OFFICE STEPLADDER Application March 17, 1937, Serial No. 131,436

1 Claim.

This invention relates to step ladders.

The primary object of the invention is to provide an improved step ladder with a folding top adapted to be unfolded and extended so as to provide a rigid top of considerable area, means of connection being provided between the folding. extensible top and the step ladder to spread the ladder into open position as the top is unfolded, and also to automatically engage the top when fully extended to hold the same rigid.

Other objects and advantages are to provide a step ladder that will be superior in point of simplicity, inexpensiveness of construction, positiveness of operation, and facility and convenience in use and general efficiency.

In this specification and the annexed drawings, the invention is illustrated in the form considered to be the best, but it is to be understood that the invention is not limited to such form,

because it may be embodied in other forms; and

it is also to be understood that in and by the claim following the description, it is desired to cover the invention in whatsoever form it may be embodied.

The invention is clearly illustrated in the accompanying drawings, wherein-- Fig. 1 is a side view of a step ladder embodying our invention.

Fig. 2 is a side view of the ladder folded up.

Fig. 3 is an enlarged fragmental side view of the operating connection between the extension top and the ladder.

Fig. 4 is a fragmental rear view of the ladder.

Fig. 5 is a plan view of a modified form of ladder shown in the extended position, and partly broken away to illustrate the interior construction thereof.

Fig. 6 is a cross section taken thru Fig. 5 on the line 6-43.

Fig. '7 is a side elevation of the ladder shown in Fig. 2, the same being in the folded position.

The ladder comprises a step member I, with steps 2, a supporting member 3 for supporting the step member, a top 4, and interlocking braces 5 for bracing the step and supporting members,

which parts are common to and constitute an ordinary step ladder.

On the sides at the top of the step member I are mounted angle iron members 6 secured to the member I and to the underside of the top 4 respectively, thereby fixedly mounting the top 4 on the top of the member I. In the rear corners of the angle iron members 6, the upper ends of legs I of the supporting member 3 are pivoted at l2.

A top extension, or platform 8, has bars 9 fixed on its under face, one end of each bar being extended as at H, and the extended ends H pivoted on the pivots i2, or at any point on the respective angle irons 6.

A platform support I3 is constructed of a pair of rails M pivotally connected at the lower ends I6 thereof to the lower ends of the respective support rails T, so that the upper ends of the rails [4 swing toward and away from the upper end of the supporting member 3. The rails M are connected to each other by fixed braces ll. The upper ends of the rails M are connected by a laterally disposed bar If! which moves below the under face of the platform or top extension8, and particularly along the bottom of the bars 9.

Onto each bar 9 is attached a wire guide H! to slidably confine the connecting bar l8 between the bars 9 and the guides 19, thus limiting the movement of the top extension 8 relatively to the upper ends of the rails M. Both ends of each guide I9 are fastened to the respective bars 9, so as to prevent the connecting bar l8 and the rails M from completely separating from the exten- SiOll 8. 25

When the extension 8 is unfolded the bar I8 slides outwardly on the guides l9 and is also pulled upwardly so as to exert an upward and outward pull on the lower ends of the legs I causing the latter to swing outwardly around the upper pivots thereof.

Adjacent the outer ends of the bars 9 are downwardly extended stops 2| with inclined sides. The sides of the stops 2| facing toward the top 4 are of a long cam-like incline and the sides 22 of the stops 2| facing rearwardly of the ladder are abrupt to prevent the connecting bar l8 from folding up when weight is placed on the top extension B. Thus the platform support I3 is rendered rigid automatically when the top extension 8 is fully extended. The guides I9 are bent downwardly below the stops 2| to accommodate the bar l8 when the same is passed over the stops 2!.

The weight of the top extension 8 holds the stops in obstruction of the connecting bar 18 and the more weight that is put on the extension 8, the more rigid the support [3 becomes. This arrangement also prevents the accidental folding of the step ladder proper, because the supporting member l3 cannot be swung without the movement of the top of the support 13 relatively to the top extension 3.

In order to fold the ladder, the top extension 8 is slightly raised to allow the connecting bar 55 8 to pass beneath the stops 2| and then the extension 8 is folded over the supporting member 3. During the folding of the extension 8 the bar |8 slides on the bars 9 toward the inner ends of the guides l9, allowing the folding of the supporting member 3 and the step member together.

The braces 5 of the step ladder 8, are arranged in pairs and are pivoted at the outer ends thereof to the respective rails or legs of the step member I and of the supporting member 3. The inner adjacent ends of the respective braces 5 are pivoted to each other. The central or meeting pivots of the opposed sets of braces 5 are.

connected to each other by a connecting element 23 formed into a hand grip to facilitate the carrying and manipulating of the step ladder.

In the modified form of ladder shown in Figs. 5, 6, and 7, we provide a step member 30, supporting member 3|, the top 32, the angle members 33, each joining the top to the step member, and the pivot 34 for pivotally connecting the supporting member 3| to the angle member 33. An extension platform 35 is provided with bars 36 on its under side. A plate 31 is secured to each bar 36, each plate having an extended end 38 hingedly journaled at its extreme end on the pivot 34.

A wire guide 39 is arranged below each bar 36, and in spaced relation thereto, each guide being secured at one end to the under side of the platform 35, and at the other end to the pivot 34. Legs 40 are provided for supporting the platform 35 in the extended position, said legs being hingedly connected at their bottom ends to the bottom ends of the respective supporting members 3|, in substantially the same manner as that set forth with respect to the corresponding parts in the preferred form of the invention. The upper ends of the platform supporting legs 40 are connected by a laterally disposed bar 42, said bar being slidably confined in the space between the bars 35 and the guide wire 39.

When the platform 35 is in the extended position shown in Fig. 2, the cross bar 42 on the supporting legs 40 rests against the outer end of the guide wire 39, and supports the platform 35 in a position parallel to the top 32. To prevent buckling or folding of the platform extension 35, we have provided a gravity actuated member 43 which is pivoted at 44 to the underside of the platform extension 35, whereby, when the latter is in the extended position shown in Fig. 3, the free end 45 of the member 43 will drop down behind the cross bar 42 to prevent it from sliding along the guide 39.

In order to fold or collapse the ladder, the gravity locking member 43 is elevated manually from a position behind the cross bar 42, enabling the cross bar and supporting legs 40 to be moved along the guideway toward the step section 30, which action permits the extension platform 35 to drop into the folded position shown in Fig. 3. When the ladder is in the folded position, the supporting legs 40 for the platform extension are adapted to assume a position alongside of the supporting member 3 to form a compactly folded structure.

Having thus described this invention, what we claim and desire to secure by Letters Patent is:

In a step ladder the combination with a step member having steps and a top fixed thereon, a supporting member pivoted to the step member below the top, and interlocking foldable braces to brace the step and the supporting members in the unfolded position; of an extension platform pivotally secured to the step member at the said top; platform supporting rails pivoted to the said supporting member and extended upwardly to the underside of the platform; a connecting element on the upper ends of the rails; of wire guides on the underside of the platform extending toward the outer free edge of said platform being spaced from the underside of the platform to slidably confine the connecting element on the underside of the platform; the ends of the guides being closed to prevent the removal of the connecting member therefrom; stops extended from the underside of the platform adapted to allow the said connecting member to pass over the stops outwardly but to be held in obstructing position by the weight of the platform, after the latter is brought into extended position, thereby to prevent the collapsing of the said rails unless the platform is lifted and folded.

ROBERT R. PARKINSON. STUART E. WEAVER.

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