US2069969A - Scaffolding ladder - Google Patents

Description

Feb. 9, 1937. ANELSCN 2,069,969

S GAFFOLDING LADDER Filed Aug. 29, 1935 NV NTOR AT RNEY i atented Feb. 9

UNITED STATES PATENT OFFICE 5 Claims.

This invention relates to scaffolding structures, and more particularly, to a combined ladder and scaffolding or staging platform.

An object of this invention is to provide a substantial and convenient scaffolding structure whereon a person can be supported, and can do work.

Another object of this invention is to provide a scaffolding structure which permits of easy and quick adjustment to different levels and positions.

A further object of this invention is to provide a scaffolding structure which can be quickly set up and quickly dismantled.

A still further object of this invention is toprovide a scaffolding structure, part of which may be used alone as a self-supporting ladder, or as a wall ladder.

Yet another object of this invention is to pro .vide a scaffolding platform which may be applied to already existing types of painters ladders.

A feature of the scaffolding structure of the present invention is its adaptability to slanting or inclined flooring or ground surfaces.

Another feature of the present invention is the small and compact size of the entire scaffolding structure when dismantled, therefore requiring only a small space for storage.

Other features and advantages will hereinafter appear.

In the accompanying drawing Figure 1 is a perspective View of the assembled scaffolding structure of the present invention.

Fig. 2 is an end view of the assembled scaffolding structure, and shows one of the scaffolding platforms set at a low level.

Fig. 3 is a section taken on the line 3-3 of Fig. 2. 1

Fig. 4 shows a detail of the catch or locking -means at the inner end of the scaffolding platform.

Fig. 5 is a detail drawing of a second clamping and locking means located at an intermediate point on the scaffolding platform.

Fig. 6 shows the scaffolding structure of the present invention supported on a slightly inclined surface, or on steps having a gradual ascent.

Fig. 7 is an end view of the scaffolding structure, and shows the scaffolding platforms shifted to one side to permit a person to ascend the ladder section and mount the scaffolding platform.

Fig. 8 is a sectional view of the scaffolding folded together and ready to be set away.

The scaffolding structure of the present invention comprises a primary supporting means made substantially in the form of a self-supporting inverted V-type painters ladder, having two similar ladder sections I0 and I I. These ladder sections have sides I2 which are joined at equal intervals along their length by rungs I3. The sides I2 may be made of pressed metal, but in the present preferred form of the invention they are of wood, and are cut transversely at their lower ends so that the bottom surfaces I4 are flat against the floor when the ladder sections are extended and supporting each other. The upper ends I5 and I6 of the ladder sections I0 and II are attached to hinge plates I'I so that said sections pivot on each other at their upper extremities.

The rungs I3 may be fabricated of metal or other suitable material, but, in the form of the invention shown, they are of wood, and are of different and graduated lengths in each ladder section. the rungs being shorter as the top is approached, so that the sides I2 tend to converge upwardly.

The ladder sections III and II are restrained from opening upon their upper hinged ends too widely by the usual metal braces I8 which are pin connected to each other and to the sides I2.

According to the present invention, there are provided scaffolding platforms I9 and 20 for the purpose of supporting persons at various levels, and which are exactly similar to each other in all details, and are adapted, as will be hereinafter disclosed, to engage widely separated pairs of the rungs l3 so that said scaffolding platforms may be secured to and supported by the ladder sections III and II.

The scaffolding platform I9 of the present invention will be described in detail, it being understood that the scaffolding platform 20 is exactly similar to the scaffolding platform I9 in all particulars and therefore requires no separate description.

A platform ortable member 2I comprises the surface of the scaffolding structure I9 which is to support a person at work. This platform 2| is attached to and supported by a pair of rungs I3 of the ladder section II], and which are not adjacent, and are also widely separated.

The outer end 22 of the platform 2| is supported from the lower of said pair of rungs I3 by means 7 a rod 21 which is held tightly therein, and which passes through two bearing members 28 fastened to the underside of the platform 2 I. The pivotally mounted structural member 23 thereby provides a simple and sturdy means of supporting the outer end 26 of the platform 2| on the lower of 'a pair of rungs I3, and a means which permits of particularly easy and quick shifting of the platforms from one level to another, viz., from one pair of rungs l3 to another pair of rungs l3.

The platform 2| is adapted at its inner end 29 to engage and be supported on the upper of a pair of rungs |3, by means of two clamp or hook members 30 (see Fig. 3) which are attached to the underside of the platform 2| by suitable screws or bolts, and which can. slip freely onto a rung l3. Although the hooks 30, due to an action to be hereinafter described, are alone sufficient to prevent disengagement, when set up, of the platform 2| with the upper of a pair of rungs |3, in the present invention this means is not relied upon solely to maintain said engagement. Accordingly, there is provided in this invention at the inner end 29 of the platform 2| and substantially in the center thereof, a catch or looking member 3| (see Fig. 4) which engages part of the outer surface of a rung l3 when the scaffolding platform is set up on a ladder section. The catch 3| occupies an aperture 32 (see Fig. 1) in the end 29 of the platform 2 I, and is pivotally attached to the underside of said platform, by means of angle brackets. This pivotal mounting permits the catch 3| to be swung upward and out of contact with its engaged rung |3, thereby permitting the release of platform 2| from said engaged rung when it is desired to remove the scaffolding. It is evident in setting up the scaffolding that, when it is desired to attach the inner end 29 of the platform 2| to the upper of a pair of rungs 3, said platform may be placed on top of said rung and shifted outward and away therefrom, wherefore the catch 24 will be depressed upwardly by the engagement of its under-slanting face with said rung, and wherefore said catch will drop downwardly after said rung has traversed said face and has entered the clamps 30, thereby locking said rung effectively to the platform. The hooks 30 and the catch 3| comprise the means whereby the inner end 29 of the platform 2| is attached to and supported by the upper of a pair of rungs 3, engaged by said hooks and catch.

7 In the present invention, the length of the strut member 23 is substantially equal to the length of the scaffolding platform l9, and the combined length of these two is not greater than the length of the ladder section I0. Also, the distance between a pair of engaged rungs I3 is substantially equal to the length of the strut member 23.

Figure 1 shows the scaffolding structure of the present invention, wherein the scaffolding platforms l3 and 2|! are attached to the upper portions of the ladder sections l and II, and wherein the inner ends 29 of said platforms are supported by the upper rungs of the ladder sections. When in this position, the platforms I9 and 20 together furnish a substantially continuous scaffolding and supporting surface extending across the top of the ladder sections, thereby providing a substantial working platform of considerable length.

For the arrangement as pictured in Fig. l, a person standing at any reasonable place on the scaffolding platforms l9 and 20 would always be located between all perpendicular planes passing through the contact areas M of the sides I2 and "the floor. Thus there would be no danger at any time of the structure getting off-balance, or out of equilibrium, due to the weight of a person on the platform H3 or 20.

When it is desired to attach a scaffolding platform l9 or 2|) to the lower portions of a ladder Section, whereby one of the lowermost rungs of said ladder section would engage and support the structural member 23, there is provided in the present invention and on the underside of the platform 2|, a second clamping means 3| a outwardly removed from the inner end 29 of said platform, for engaging the upper rung of the pair of rungs l3 which are to support the platform.

By providing the platform 2| with said second clamping means 3| a to permit the upper of a pair of engaged rungs to support said platform at an intermediate point outwardly removed from the inner end 29, and when said platform is supported on the lower portions of a ladder section (see Fig. 3, left platform), there isavoided a danger of unstable equilibrium and of tipping which would obtain if said platform were supported at its inner end 29 and a person were to stand on the outer section 22 of said platform. For, if a platform 2| being supported on the lower portions of a ladder section were to have its inner end 29 supported by the upper of a pair of engaged rungs, the outer portion 22 of the platform would be outside of a perpendicular plane passing through the contact surfaces l4 of the sides |2 and the floor, and a person standing on said outer portion 22 might cause the whole scaffolding structure to tip and overturn, resulting in danger to life and limb, and injury to property.

Figure shows a detail of the clamping means 3|a. A cleat member 32a is fastened to the underside of the platform 2 I. Attached to the cleat 32a are clamps 33 having jaws suitable to receive and engage a rung |3. A spring catch or looking member 34 is fastened to the center of the underside of the platform 2| by suitable screws, and projects under the cleat 32. The end 35 of the catch 34 is bent upward, and extends into an aperture 35 in the cleat 32m. The free portion of the catch 34 can move upward to allow a rung i3 to be inserted into or removed from the clamps 33. Normally, the catch 34 is in the locking position shown in Fig. 5, it being depressed upwardly by contact with a rung l3 when the latter approaches the clamps 33.

Because of the angle which the structural member 23 makes with the vertical, the force exerted on the outer end 22 of the platform 2| may be resolved into a vertical upward component, and a horizontal outwardly directed component. As is well known to one versed in statics, the

vertical component cannot tend to move the platform in a lengthwise direction; the outwardly directed horizontal component, however, is continually acting to move the platform 2| outward, and acting to hold an engaged rung |3 tightly in the jaws of the engaging hooks and against the inner surface of said jaws. Therefore, said hooks bear the greater part of the lengthwise force exerted on. an engaged rung |3, and the catches 3| and 34 are thus required only to prevent disengagement of the platform and rung due to incidental jarring or jolting of the scaffolding struc ture.

The scaffolding platforms l9 and 20 of the present invention are adapted to engage the rungs l3 only of the ladder sections I 0 and II, and do not require engagement with any other parts of said ladder sections. Therefore, the scaffolding platforms I9 and 23 may be used with any similar type of ladder sections, and it should be understood that said scaffolding platforms of the present invention are not limited to the particular ladder sections described herein.

An important use of the scaffolding structure of the present invention is shown in Fig. 6. The ladder sections H and I l are resting on a slightly inclined surface, or on a flight of steps (shown in dotted lines) having a gradual ascent. Notwithstanding the inclination of said surface supporting the ladder sections, it is possible to attach a scaffolding platform l9 to the more upwardly faced ladder section so that said platform will be in a substantially horizontal position, and will afford a rigid and strong support upon which a person may stand or sit and do work.

From the foregoing, it can be understood that the scaffolding platforms [9 and 2B of the present invention are not mere shelves, but are sturdy and substantial stagings for supporting persons who have work of a manual and vigorous nature to do. Said platforms are adapted to extend from the front portions only of backwardly slanting ladder sections and require engagement with strong rungs which are not adjacent to each other but are widely separated to act as substantial and adequately safe members upon which to fasten.

In order that a person may ascend a ladder section, and step onto the platform thereto attached without difficulty, the platform 2! and its structural support 23 are made narrower than the ladder sections l0 and II, and said platform and structural support may be shifted sideways, as shown in Fig, 7, to provide a clearance sufficient to permit a person to ascend said ladder section and mount the scaffolding platform. Or, if desired, only one of the scaffolding platforms may be used at a time, in which case the ladder sec tion not having a scaffolding could be used to ascend to the scaffolding platform mounted on the remaining ladder section.

Figure 8 shows the scaffolding structure of the present invention collapsed for transportation or storage. It should be noted that the scaffolding platforms 2| hang from the upper rungs of the ladder sections by means of the hooks 3t, and fit closely to said ladder sections, and that when the structure is in this collapsed position, the cleat members 32 do not interfere with any of the rungs I3, but that each cleat member 32 fits between a pair of said rungs.

It should be noted that the ladder structure of the present invention provides a particularly sturdy means for supporting a scaffolding, and that a complete structure of this type is much steadier and more substantial than scaffolding heretofore employed, and using wooden horses and the like for support. Also, the ease with which it is possible to mount and descend from the scaffolding of the present invention is a desirable feature not heretofore found in scaffoldings employing wooden horses for support. Furthermore, as has been already pointed out, the ladder structure of the present invention may be used alone, as a substantial self-supporting ladder, or as a wall ladder, and a need for such often arises when work is being done of a nature which, for the most part, requires scaffolding.

Variations and modifications may be made within the scope of this invention and portions of the improvements may be used without others.

Having thus described the invention, what is claimed as new and for which it is desired to obtain Letters Patent, is:-

1. In combination with an inverted V-type self-supporting painters ladder having rungs, two scaffolding platforms extending substantially horizontally outward from the outer faces of the upper portions of the backwardly sloping ladder sections, one platform being on each lad-der section, and so that they together form one continuous scaffolding and supporting surface having a length at least equal to the separation of the lower portions of said ladder sections; hooks on the underside of each platform to engage the upper of a pair of non-adjacent and remotely separated rungs on a ladder section disposed with a plurality of rungs therebetween; and a strut member pivotally attached to the outer end of each platform for engaging and supporting same from the lower of said pair of rungs on a ladder section.

2. In combination with an inverted V-type self-supporting painters ladder having rungs, a scaffolding unit comprising a platform and means for mounting said platform to extend substantially horizontally outward from the outer face of the upper portion of one of the backwardly sloping ladder sections, said platform being of such a length that, when a pair of said scaffolding units are mounted to extend substantially horizontally outward from the outer face of the upper portion of each of the backwardly sloping ladder sections, both said platforms together form one continuous scaffolding and supporting surface having a length at least equal to the separation of the lower portions of said ladder sections, said mounting means including hooks on said scaffolding unit one to engage an upper rung on a ladder section and the other to engage a lower rung on that same lad-der section with these rungs separated by a plurality of other rungs therebetween, the first-mentioned hook being on the underside of said platform, said mounting means also including a strut member pivotally attached to the outer end of the platform for supporting the same by way of said lower rung, and the second-mentioned hook, which as aforesaid engages that rung, being near the lower end of said strut member.

3. A structure as define-d in claim 2, wherein said strut member is substantially equal in length to said platform so as to suffer mainly a compressive stress under platform load, and wherein said platform carries an additional hook on its underside located between the first-mentioned hook and the point of pivotal attachment of said strut member to the platform, said additional hook being located below said first-mentioned hook and below said point so that when the platform is shortened as to its extension outward from said ladder section, by substituting said additional hook for the first-mentioned hook as an engaging means for said upper rung, the platform is maintained substantially level and at the same time the strut is held in this case also to suffer mainly a compressive stress under platform load.

4. A structure as defined in claim 2, wherein a catch is associated with the hook on the underside of the platform, such catch including a movable part, said part being weighted so as always to be biased to lock said hook on said upper rung, and said part having a ramp-shaping so placed thereon that in advancing the platform lengthwisely over said rung in a direction to move the bill of said hook embracingly of said rung said catch will be opened to permit such embrace to be completed and at the conclusion thereof will automatically, due to its bias as above, close and thereby lock the hook to said rung.

5. A structure as defined in claim 2, wherein embracingly of said rl'ing' said catch will be opened to permit such embrace to be completed and at the conclusion thereof will automatically, due to 7 its bias as above, close and thereby lock the hook to said rung.

EDWIN A. NELSON.

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