US2901054A - Combination scaffold-ladders - Google Patents

Description

Aug. 25, 1959 2,901,054

C. E. LARSON COMBINATION SCAFFOLD-LADDERS Filed Aug. 28, 1956 5 Sheets-Sheet 1 INVENTOR CLAYTON E. LARSON war! ffil/mm ATTORNEYS Aug. 25, 1959 c. E. LARSON 2,901,054

COMBINATION SCAFFOLD-LADDERS Filed Aug. 28, 1956 5 sheets-sheet 2 INVENTOR CLAYTON E. LARSON ATTORNEYS C. E. LARSON COMBINATION SCAFFOLD-LADDERS 5 Sheets-Sheet 3 Aug. 25, 1959 Filed Aug. 28, 1956 Aug. 25, 1959' c. E. LARSON COMBINATION SCAFFOLDLADDERS Filed Aug. 28, 1956 5 Sheets-Sheet 4 I I'm-1| "III.

INVENTOR CLAYTON E. LARSON ATTORNEYS Aug. 25, 1959 c. E. LARSON COMBINATION SCAFFOLD-LADDERS 5 Sheets-Sheet 5 Filed Aug. 28, 1956 INVENTOR CLAYTON E. LARSON ATTORNEYS United States Patent COMBINATION SCAFFOLD-LADDERS Clayton E. Larson, Weston, Conn., assignor to White Metal Rolling & Stamping Corporation, Brooklyn, N.Y.,- a corporation of New York Application August 28, 1956, Serial No. 606,605

3 Claims. (Cl. 182-27) This invention relates to combination scaffold-ladders. More particularly, it is concerned with new combination-v ladders which take the form of straight extension ladders when arranged for storage or one method of use but which may be converted by simple pivoting of sections into adjustable height scaffolds or into offset ladders.

Field of invention The manufacturer who sells equipment or appliances which are only used infrequently by the purchaser, stands a better chance of selling his products if he can devise and produce them in such form that they can be employed for a variety of uses, rather than just one type of use. This holds true for a number of different products, but ladders represent one field in which combination products are particularly desirable. Thus, if a ladder is designed so that it can be employed in a number of basic ways so that it takes the place of two or more normal ladders or related products, less space is required for the storage of the ladder between uses. Furthermore, the combination construction is highly desirable for paper hangers, painters and other tradesmen, since, obviously, it is much less trouble to transport one ladder instead of several in going from one work location to another.

Various forms of combination ladders have been devised and produced in the past, such as step ladders which are convertible into extension ladders. Furthermore, combination ladders which are convertible into scaffolds have been known before, and various types of these combination scafiold-ladders are described in US. Patents 80,581; 513,012; 1,636,085; and 2,012,592.

Although combination scaffold-ladders are basically not new, there has been no widespread use or sale of such products in the past, becauseof a number of reasons. First, prior designs of such combination ladders have had certain inherent defects which create safety hazards when the product is used either as a ladder or as a scaffold. Second, many of the known designs have been bulky, unwieldy, or difficult to convert from the ladder form into the scaffold form. Finally, many of the combination ladders have been of such design that when set up in the ladder form, the resulting ladder was merely a single straight ladder which could not be adjusted as to length, so that the usefulness of the device as. a ladder was relatively limited.

Objects A- principal object of this invention is to provide new improvements in combination scaffold-ladders. Further objects include:

(1) The provision of a combination product which can be set up in one form to serve as a straight ladder that may be adjusted in length, and by a simple folding operation can be converted into a scaffold which provides a horizontal working platform that can be held at an adjustable height above the ground upon two vertically extending standards.

(2) The provision of combination scaffold-ladders I P ce which are every bit as safe to use in either the ladder form or the scaffold form as are any known individual ladders or scaffolds.

(3) The provision of combination scaffold-ladders so designed that they can be made from light metal alloys such as aluminum or magnesium to provide a structure which is strong, relatively very light in weight, and easily portable.

(4) The pro-vision of new features in combination scaffold-ladders which make it possible to manufacture the ladders at a price which will be attractive to prospective users and purchasers, and which also Will create more widespread use of the products because of the ease with which the ladders can be handled and converted from the ladder form into the scaffold form, or vice versa.

Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

General description These objects are accomplished according to the present invention by forming a combination ladder with a cross-membered center section having connected thereto two end sections, providing the end sections in turn with telescoping extensions, and providing means to hold the end sections in an extension ladder position and separate means to hold them in a scaffold position.

Preferably, the means for holding the end sections in a fixed position aligned with the central section creating the extension ladder forms of the device comprises snap pins and a pair of side plates. Also, the end sections are connected to the center section by pivot pins which allow the end sections to be swung around to form two vertically extending supports or standards for the central section, which then becomes a horizontal platform, when the ladder is converted to a scaffold.

A separate planking is provided which fits snugly over the cross members of the central section, forming a continuous surface platform for the user of the scaffolding unit.

The telescoping portions of the end sections are designed so they can be extended to raise or lower the height of the horizontal work platform in the scaffold or adjust the length in the ladder form with adjustment sustained by suitable holding means such as snap pins.

When set up as a scaffold unit, the side plates which serve to hold the end sections of the ladder aligned with the central section when positioned in the extension ladder form, are designed so that they may be fixed to the upper ends of the vertically extending end sections to form horizontal members which serve as safety guards and also as bucket and tool racks.

The means for holding the end sections in avertically extending position'running about perpendicularly to the central'section when the unit is set up in the scaffold form comprise hinge straps and locking toggles.

In the preferred form, the new ladders also include paddled tread feet and bracing elements designed to increase-the structural strength and safety features of the units. 7

Detailed description A more complete understanding of the new devicesof this invention may be had by reference to the accompanying drawings in which:

tions;

Fig. 2 is a side view of the device shown in Fig. 1, illustrating its use as an extension ladder against a wall;

Fig. 3 is a side view of the product shown in Fig. 1, illustrating its appearance when setup inithe scaffold arm;

Fig. 4 is-a perspective view of. a planking sectionused with the new devices to form a horizontal flat surface working platform;

Fig. 5 is a top plan view of'the device whensetup-as a scaffold as shown in Fig. 3;

Fig. 6 is an enlargedfragmentary sectional side view taken along the line 66 of Fig. 5, illustrating some of the structural details of the devices;

Fig. 7 is an enlarged fragmentary sectional view taken along the lines 77 of Fig. 3;

Fig. 8 is an enlarged fragmentary sectional view taken along thelines 88 of Fig. 3;

Fig. 9 is anenlarged fragmentary sectional view taken along the lines 99 of Fig. 3;

Fig. 10 is an enlarged fragmentary sectional view showing details of construction of the snap pin fastening elements of the new ladder devices;

Fig. 11 is a diagrammatic perspective view showing the unit when in the extension ladder form, the figure being designed to aid in describing the method of converting the ladder from one form to another;

Fig. 12 is a diagrammatic perspective view similar to Fig. 11, but showing the device converted into the scaffold form.

Referring in detail to the drawings, the new devices basically comprise a central section 2, two end sections 4 and 6, means 8 for retaining the unit parts in the extensionladder form, means 10 for retaining the unitsections in the scaifold form, means 12 for extending the length of end sections 4 and 6, and a plank section 14.

The central section 2 comprises two side rails 16 and 18,- and a plurality of cross members 20 spaced apart from one another and extendingv perpendicularly between the two side rails 16 and 18. Althoughthe cross members 20 can be made in various forms, such as flat surfaced channel pieces, they are preferably tubular rungs provided with serrations 22 designed togive the rungs 20 a non-slip surface.

Although the side rails 16 and 18 and rungs 20 can be made of a variety of different materials, e.g., wood, preferably the new devices are made of light weight metal alloys such as alloys of magnesium or aluminum. In this case, each side rail (see Fig. 7) is formed of an extruded metal channel having a central web 24 and two inwardly turned ends 26, and the rungs 20 are made of extruded metal tubing. The metal rungs are aflixed to the side channels 16 and 18 by being inserted into sized holes which are punched or drilled in the side rails and then welded in place by a ring of welding 28.

The end sections 4 and 6 each comprise a pair of side rails 30 and 32 and a plurality of cross members 34. Here again, a choice of materials formaking the cross members and side rails is available, but preferably side rails 30 and 32 are made of the same type of extruded light metal alloy channels as the side rails 16 and 18, and the rungs 34- are made of the same extruded, serrated metal tubing as the rungs 20. However, as can be seen in Figs. 1 or 8, the rungs 34 are made in diflierent length than the rungs 20. Thus, the end section .rungs 34 are of such length that the inside distance between the end section side rails 30 and 32 is just slightly greater than the outside distance between the side rails 16 and 18 of the center section 2. The rungs 34 are fixed to the side rails 30 and 32 by beingwelded into suitably drilled or stamped holes in the side rails, just as in the case of the rungs of the center section 2, except that the center section has the turned in ends .26 of the side railspointed'inward, whereas the channels forming the side rails 30 and 32 have: only the center web 24-facingthe rungs 34.

As can 'be seen in Fig. 1, this design for the center section 2 and end sections 4 and6, makes it possible for the end sections to fit right over the center section, with the web portions of the side rails 16 and 30, also 18 and 32, facing each other with just a fraction of an inch space between them.

The rungs 20 of the center section 2 are equally spaced from each other and are distributed along substantially the entire length of the center section. The rungs 34 of the end section are also suitably spaced apart, but they do not extend along the entire length of the end sections. Thus, a substantial portion of the end sections toward the inner ends 36 thereof possess no rungs, so that the end sections may be fitted over the center section as previously described.

The end sections 4 and 6 are both connected to the center section 2 by pins 38 which serve as pivot points about which the end sections 4 and 6 may be rotated relative to the center section 2. Preferably, spacing washers are fitted over thepins 38 between the side rails of the center and end sections beforethe pins are fixed in place, such as by peening.

Obviously, the center section2 and end sections 4 and 6 may be made in a variety of lengths, but both end sections should be of equal length. The rung-free ends 36 of the end sections 4 and 6' will have a length, however, which is controlled by the length of center section 2. Thus, the rung-free ends 36 of sections 4 and 6 should be of such length that the distance from the pivot pins 38 to the tips of ends 36 will be equal to one-half the distance between the pivot pins at one end of the center section and the pivot pins at the other end of the section, minus approximately the outside distance between center section side rails 16 and 18.

In order to brace the end sections, strips of extruded metal channels 46 approximately semi-circular in cross section are welded at one end to'the top rung 34 and at the other end to the side rails 30 or 32 of the end sections.

The fastening means 8 for holding the end sections 4 and 6 longitudinally aligned with center section 2 when the device is set up in the extension ladder form, comprises side plates 42 and 44 and snap pins 46. The side plates 42 and 44 are extruded from the metal with a special shape which can be best seen in Fig. 6. Thus, the plates have a central web 48 and two perpendicularly depending sides 50, plus an offset extension 52 and a second offset extension 54. The extension 54 is further from the center web 48 than the extension 52, so that when the unit is set up in the scaffold form as shown in Fig. 6, the plane which passes through the top surfaces of both extensions 52 and 54 will be parallel to the horizontal plane of the center section 2. As a result, the side plates can serve when the unit is set up in the scaffold form as level rests for paint pails, buckets or the like.

As shown in Fig. 10, the snap pin members 46 extend through holes punched or drilled in the side rails and are slidably held in the holding element 148 which is fixed to the side rail by rivets 150, and lugs 152.

Snap pins 46 are urged toward the side rail by coil spring 154, which is fitted around the pin 46 between the end 56 of the holder 48 and a cotter pin 58 which extends through a hole in pin 46. As can be seen from Fig. 1, there are a total of 'four snap pins fastened to the central section 2, a pair of these pins being located near one end of the center section to be used in holding end section'4 in aligned position by engaging the holes 59 in the endsection side rails, While the other pair is positioned near the other end of the center section for use in holding the end section 6 in aligned position by engaging similar holes therein.

' The side plates 42and 44 cooperate with the snap pins 46 in retaining the end sections 4 and 6 in the position illustratedin' Figs. land 2. Thus, the end 60 of side plate 42 is permanently connected by pivot pins 62 to the inner end of side rail 30 of end section 4, while the end 64 of side plate 44 is fixed by pivot pins 66 to the inner end of the side rail 32 of end section 6. The pins 62 and 66 permit the side plates to be swung from the position of holding end sections 4 and 6 aligned, as shown in Figs. 1 and 2 over into the cross-over position shown in Figs. 5 and 6 when the unit is set up in the scaffold form. Each side plate is provided with a cotter pin 68,

attached to the side plate by a chain 70 so as to prevent the cotter pin from being lost. The cotter pins slide through mating holes in the side plates and in the tips of the end section side rails, so that when they are thus inserted, the side plates 42 and 44 are rigidly coupled to the side rails 30 and 32.

The holding means 10, used in retaining the end sections 4 and 6 in a position very nearly perpendicular to the center section 2 when the units are set up in the scaffold form, comprise four hinge straps 72, each of which is pivotally fixed upon a pin 74 fastened to one of the side rails of one of the end sections away from its associated hinge pin 38 a distance about /3 the length of the hinge strap 72. As can be seen in Fig. 7, the opposite end of the hinge strap 72 carries a toggle button 76 which is formed with a toggle recess 78. Each one of the side channels of the end sections 4 and 6 are provided with a mating'hole into which the toggle buttons 76 may be inserted, and then the hinge straps can be locked in place by swinging the toggles 80, which are pivotally fastened to the corresponding side rail upon pins 82, into the recess 78 of the toggle button 76.

Extension means 12 are used to longitudinally extend the ladder when it is set up in the form shown in Figs. 1 and 2, or to raise and lower the level of the horizontal platform when the unit is set up as a scaffold, as shown in Fig. 3. This means 12 comprises special-shaped, extruded metal channels 84, snap pins 86, a rung 88, and feet units 90.

The special shape of the channels 84 is illustrated in Fig. 8. Roughly speaking, these channels are rectangular tubes which have a bowed-in innerface 92 and side lugs 94 so shaped that channel members 84 will snugly telescope in the end section side rails with the side lugs 94 hooking into the turned in ends 26 of the side rails.

A series of holes 96 are provided in the innerfaces 92 of the channel members 84 spaced apart, for example, at three inch intervals and of such size as to just allow the snap pins 86 to pass through them so that the'side channels 84 can be fixed at any one of the levels corresponding to the holes 96. The general construction of the snap pins 86 is the same as that of the snap pins 46 described in connection with Fig. 10.

Rungs 88 are attached at each end to a channel member 84 in the same fashion as rungs 34 or 20, i.e., by passing through mating holes in the channel members and then being welded at their ends to the channel members.

The feet members 90 consist of an extruded metal outrigger 98 having a base portion 100, an upwardly sloping side portion with top extension 102, and an upwardly extending base lug 104. The outrigger 98 is fastened by rivets extending through portions 102 and 104 to the channel'members 84. Rubber pads 106 are fixed, such as by rivets or cement, to the foot base 100. A brace angle 108 is welded at one end to the rung 88 and riveted at the other end to the base 100 of the foot member 90.

The plank or platform section 14 consists of a pair of extruded metal U-shaped (see Fig. 9) channel members 110 which are held spaced apart by two angle strips 112 riveted to each end of the channel members 110. On the under side of the channel members, there is another pair of shorter angle strips 114 held in place by rivets which extend through the turned-in free ends of the channel members 110. These locking angles 114 are placed back a short distance from the ends of the members 110, and the space between the two locking angles 114 is adjusted so that when the plank unit 14 is placed upon the center section 2, these angles will fit snugly between two of the rungs of the center section, as can be seen in Fig. 6. Hence, the angle strips serve to hold platform unit 14 on the center section 2 and prevent the planking from sliding along or turning about the center section. Moreover, this construction enables the planking unit 14 to be quickly placed into position or removed from the center section Whenever the ladder unit is converted from the extension form into the scaffold form. One or more spacer strips 116 are also riveted in place on the under surface ofthe channel members 110 to serve to further strengthen the planking and keep the channel members 110 properly space along their entire length. The top surface of the members 110 are fluted to provide better traction.

Method of use The new scaffold-ladders are normally stored and kept in the position for use as an extension ladder, as shown in Figs. 1 or 11. When set up in this form, the device is used in the same fashion as any other straight extension ladder, as illustrated in Fig. 2.

The length of the ladder can be adjusted by moving the telescoping extension sections 12 at either end. This adjustm'ent is made by pulling in the snap pins 86 on the section to be extended to disengage the pins from the mating holes 96 in the channel members 84. This allows the extension section 12 to slide along within the side rails of its end section, and when the desired amount of extension has been obtained, the snap pins are allowed to move in to again engage a new set of holes 96. Before climbing the ladder, all of the eight snap pins 46 and 86 should be checked-to insure that they are properly engaged, and also the side plates 42 and 44 should be checked to make sure that the cotter pins 68 are properly placed.

The method of converting the new units into the scaffold position can best be appreciated by reference to Figs. 11 and 12. This conversion is accomplished by first laying the ladder upon the floor or some other support, in a horizontal position, with the four hinge straps 72 on the downward side. The cotter pins 68 in the side plates are then pulled from their holes and the two side plates are both swung outward, as shown in Fig. 11. Next, the snap pins 46 holding each of the end sections 4 and 6 are pulled in to disengage the snap pins from the mating holes 59 in the end section side rails. This permits the end sections 4 and 6 to swing down, as shown in Fig. 11, as the center section 2 is lifted up to an elevated position. When the end section reaches a nearly vertical position, as shown in Fig. 6, the hinge straps on the end section are moved up and the toggle buttons 76 are inserted into the mating hole in the center section side rails, after which the toggles 80 are moved down into the toggle button recess 78 to lock the hinge strap 72 in place, as shown in Fig. 7. Then the side plate 42 and 44 are swung across the top of the end sections 4 and 6 and the cotter pins 68 are inserted in the mating holes in the end section side rails to lock the side plates in this horizontal position. Next, the plank section 14 is lifted onto the top of the center section 2 and is nested into position as controlled by the locking angles 114. The height of the horizontal platform of the scalfold can then be adjusted (see Fig. 3) by withdrawing both snap pins 86 in an end section to disengage them from the mating holes 96 and permit the channel members 84 to be telescopically moved, relative to the rest of the end section, to the desired position.

When the new units are employed in the ladder form, one end section can be swung in a perpendicular position and locked there by the fastening means 10 to serve as a spreader to keep the ladder and the user away from a wall and provide freedom of working room. Here again, adjustments at both ends of the unit can be obtained in the fashion previouslydescribed, so that both the height of theladder'can be adjusted, as well as the distance that theladderf is held backfrom the wall;

The outstanding versatility of the new devices is further. demonstrated by another manner. in which the device can be. used asv a scaffold. Thus, a scaffold can b formed. from the unit by keeping one end section aligned with the centersection and fastened in this position by the snap pins 46, While the other endsection is swung into a vertical position and heldthere by the fastening means 10. When so arranged, the aligned end section can be supported at its end on a step or stage, while the vertically extending section is adjusted in height so that the center and aligned end section assume a horizontal position. With this setup, the plank unit14 can bemoved along the entire horizontal portions to pro vide the user with a flat working surface all the way from the step or stage out to the vertically extending end section.

As previously mentioned, when the unit is set up in scaffold form and the side plates are swung into a horizontal position as shown in Fig. 6, they can be usedas bucket or tool racks. Furthermore, they provide a very useful safety feature, since they prevent the user of the ladder from accidentally going too far along thehorizontal platform, where the user might accidentally fall off the end of the scaffold.

The combination scalfold-ladders described above are of such design and construction that not only do they provide in one unit the utility of several normal pieces of equipment, but they also afford the user with the ultimate in safety andconvenience. Furthermore, the new designs enable the devices to be made of light metal and still be strong and capable of standing hard use without breaking. Also, because of their unusual design, they can be manufactured without complicated parts in economical production operations so they can be marketed at attractive prices to potential purchasers.

I claim:

1. A combination scalfold-ladder comprising: a center section including two unbroken side rails and a plurality of equidistantly spaced rungs fixed between the side rails, and two end sections, each including two side rails and a plurality of rungs fixed between said end section side rails, with at least one-half the length of the end sections containing no rungs, the rungs in the end sections being of such length that the end sections are just about wide enough to slip over the center section, one of said end sections being fixed upon pins to said center section, so that the rung-free portion of the end section may rotate past the side rails of the center section, the other of said end sections being similarly fixed to the center section upon the remaining end of the center section, an extension section telescopically carried by each end section at the rung-containing end thereof, spring-biased pin means to hold each extension section at various extension positions relative to its respective end section, a side plate which is at least as long as the distance between the tips of the two end sections when. they are folded over the center section and aligned therewith, said plate being hinged at one end to the inside tipof one of the side rails of one of the end sections, a second similar plate being hinged at one end to the inside tip of the side rail of the remaining end section which is diagonally opposed to the side rail to which said first plate is hinged,

snap pin means carried'by the center section side rails designed to engage. openings in the side rails of the end sections and hold them in said center section aligned position, and:hinge strapmeans carried by the end sections adapted to'hold'the'end sections in a position about perpendicular tothe center section to create vertically extending standards for the center section to form a scaffold unitin" which the center section creates a horizontal I platform support.

2. A scaffold-ladder as claimed in claim 1, in which said telescoping extension means comprise a pair of rectangular shapedtub'ular metal channels having side extendinglugs, said end section side rails comprising extruded metal channels formed with a flat web portion and integral turned-in ends, said tubular channels being of such size that the lugs thereof slidably interlock with the turned-in ends of said side rail channels, said tubular channels being fixed'apart from one another by a rung which is welded to the ends of both of the tubular channels, the tubular channels being provided with a series of equidistantly spaced holes, and said spring'biased pin means being snap pins adapted to engage said holes so as to fix said telescoping extension means at various extension positions relative to the end sections.

3. A combination scaffold-ladder comprising a center section including two unbroken side rails and a plurality of equidistantly spaced rungs fixed between the side rails and two end sections, each including two side rails and a. plurality of rungs'fixed between said end section side rails, the end section rungs being of such length that the inside distance between the end section side rails is just slightly greater than the outside distance between the side rails of said center section, one of said end sections being pivotally fixed to said center section upon pivot members which are located near one end of said center section, the other of said end sections being similarly fixed to the center section near the remaining end thereof, the pivot members being connected to the side rails of the end section so that the distance from the inside tip of each end section side rail to its pivot point is approximately equal to one-half the distance between the two longitudinally separated pivot members minus said outside distance, and two side plates slightly longer than said outside distance, one of said plates being hinged at one end to the inside tip of one of said side rails of the end sections and the other plate being hinged at one end to the inside tip of the diagonally opposed side rail of the remaining end section.

References Cited in the file of this patent UNITED STATES PATENTS

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