US1778898A - Stepladder - Google Patents

Description

Oct. 2 1, 1930. KONlGSBERG 1,778,898

STEP LADDER Filed Oct. 15, 1927 ATTORNEY Patented Get 21, 1930 are aosnrnxomes anne, on NEW YORK, 1v. Y. I I

sTnPLAnnER Application filed October-15, 1927. Serial Iio. 226,319. 7

V 7 This inventionrelates to step-ladders used.

by artisans and others upon substantially level surfaces to reach otherwise inaccessible height-s.

Commercial step-ladders ordinarily consist of a pair of risers connected by fixed treads and pivotally joined at their tops to rear legs or struts, also rigidly connected together from .side to side, the over-allwidth of the risers and struts being essentially the same.,

7 As such laddersare commonly quite narrow at their bases, they are easily tipped over sidewise by persons in reaching laterally outward,

beyond the center of "gravity, causing falls andconsequent injury. 7 r L I j It is therefore the principal object of the present invention to provide a step-ladder in which the struts are pivotally connected to the ladder at their upper ends, permitting angular separation or spread at their bottoms to any requisite degree, and means combined therewith for rigidly maintaining-them in such adjustment.

Another important object .is to provide means whereby the strutsmay be extended at various angles rearwardly relative to the risers and securely held in. adjustment by a single element. 7 1, 1 o

A further feature is in the provision of'a step-ladder having essentiallythree points of support and hence substantially free from danger in tipping sidewise.

Other advantageous features include a collapsible platform suspendedin a novel manner in the upper portion of theladder, and

having means to prevent displacement when collapsed and the ladder folded. i 7

These and'other'ob'ects are attained by the novel construction, combination and-arrangement of parts hereinafter described and shown in the accompanying drawing, constituting a material part of this disclosure and inwhich: I 1

Figure lis' jafrontelevational view of a step ladder madein accordance'withtheinvention, the partsbeing in a folded positionQ; Fi ure 2 is a front elevational view of the same: showing the struts as fully extended in full lines and as partially extended in broken 7 lines. 7 j i V Figure .3

ladder as arranged with reference to avertical wall, with one of the struts broken away to show the strut clamping means. Figure 4: isanother side elevationalview of the device as when fully extended.

"Figure 5 is a fragmentary sectional iview of the clamping means, the section being taken substantially on line 55of Figure 3.

As indicated in the draw1ng, the front portion of the ladder is of conventionaldesign consistingoof. a pair of risers 10-connected'by' a plurality of rungs-11,112 11 ,11, etc; and having between-them a series of treads 12, 12 12 312, etc. disposed immediatelyabove the rungs.

Y s thelrungs pass through risers, in' Y 1 which they are firmly secured, and the treads V are arranged to abut the inner sides of the risers, it 'will be seen that an exceptionally firm structure is provided; The tops of the risers are cutat an is a side elevational View ofthe i V v angleand, have engaged over thema top plate 13'ar- P ranged preferably to overhang the sidesand also extend slightly to the rear., Immediately below'the top plateis a cleat 141 arranged transversely and on eachof ,the rear edges of the risers are secured strap 'brackets 15 presenting eyes 16 midway in their lengths in which are journalled pintles 17 extending oppositely-' outwar d fIOlIL-Zt hollow metallic 7 frame or casing 17 obviously other analogous means may be used for pivotally connecting the casing to the brackets. f. j

A. pair'of truts 18 are pivotally engaged independently to the casing 17 by pivot bolts 19, and rigidly secured to the inner side of the casing 17 is a narrow sheet metal strip 20' extending vertically "downward past the jcenter.v of the ladder and having in its lower portion a slot 21. I i [j Slidable, but non-rotatable, in the slotisj-a clevis bolt 22 having a reduced screw-threaded portion j 23 passing through the openings 2a,.p'ivoted at their outer ends to the struts 18, the bolt being provided with a clamp nut' 25 having a conveniently operable lever'handle. 1

'inlthe adjacent inner lends of'a pair of links when the struts 18 are spread to their utmost extent, the links2l will assume a substantial-;

ly horizontal position, the bolt 22, at that time being in the lowermost portion of the slot 21, and it'will be apparent thatupon moving the struts 18 inwardly, as shown in the broken line position in Figure 2,the links 24 will assume an angular position'and the bolt 22 be raised, so that when the, struts arein close proximity, it will be nearlyor quite at the top of the slot, and dueto the clamping nut 25, the struts are held'rigi'dly in any adjusted position. in rwhich they maybe placed, as

shown in Figure 2. s v

It is sometimes desirable to erect a ladder closely adjacentcan upright wall, in which case by placing the hook 28 in the opening 29 in the tread 12, thejstruts will beheld substantia'lly vertical, while if the'hook be placed inlthe openingjin the tread 12 the struts will be extended at an extreme angle from the risers as shown in Figure 4:; V I Asth'e hook rod 27 securely but pivotally engages with'the head of the cle'vis bolt 22, it willbe seen that the struts are'always held in" rigid relation'to the risers,"except when it is desire'dito collapse the ladder, atfwhich time the bolt will be'dis posed in the uppermost part of the slot 21, the hook disengaged from the treads and permitted to hang pendant.

' In order to render it impossible to spread the struts'and risers beyond a safe limit, in case it is forgotten to engage the hook, a

safety chain 35 is attached at its ends re- -ends the sides 31 of a'platform or seat'32 adapted to swing between-the risers 10, as shown best in Figures 3 and 1,111 which views will also be seen that the platform sides '31 are notched so as to engage over the rung 11, thus preventing swinging of the platform and providing a firm support.

When it is not desired to make use of the platform it is folded to hang pendant adjacent the links 30, said links having recesses 33 in their lowerends adapted to engage the rung 11 when the ladder is collapsed and at the same time lugs 34: on thelower edges of" theside elements 31 engage the frontfside edges of the links, thereby maintaining the platform inaninoperative position between the risers and struts. r

From the foregoing it will be seen that the risers, regarded as a unit, together with the struts when spread at their bases and held at an angle outwardly, present a substantially three point surface contact, tending to unusual safety and firmness in use:

As all the adjustments are-,Inaintained by a single, easily actuated andeflicientclaniping means,together with a single central hook rod the structure possesses an exceptional degree of rigidity when in use, and permits compact foldlng for storage or transportation, rendering the device desirable because ofitsadvantageous features. The foregolng d sclosure is to be regarded as descriptive and illustrative only; and not a single' 'clamping means for the angular movement between sent struts the 'an'gle of which may be widely variant, said clamping means being fixed centrally between the strutslf V 2i Asteplad'der having fi 'xedrisers, a casing pivoted on a transverse axis at the upp'erportion ofsaid riserspa pairofstruts pivoted in s'p'aced relation in said oasing to swingtowards and fronion'e another, means toequalize the angular inclination of said struts, and means for clampingthe struts in any angularadjustment: 5 1 r H 3. Astep ladderhaving 'fixed -risers,-a"cas ingpiv'otedon a transverse axis at the upper portion of said risers, a'pairofstruts pivoted in spaced relation in said casing toyswing towards and from one another, a slotted downwardly extending plate: fixed on said casing torea'chbelow therenter of length of said struts, a pivot; bolt slidabl'ein theplate slot, links pivotally attached to; said struts connecting with said bolt, and a manually operable nut on said bolt. to clamp the links to said platef. J j i, y p

A step ladder having fixed jr'isers,fa casing pivoted on avtransvers'e axisa't'the upper portion of said r1sers, a -p air of struts'jpi'vot- Jed 1n spaced relat on? 111321161 casmg 'to swing towardsfand from one anoth er," a slotted downwardly extending plate fixed on said casing, a pivot boltslidable in the plate slot,-

links pivotally attachedto said s'truts connecting with said bolt, a lever actuated nut on said bolt to clamp the links and plate when said struts are in adjustment, and means pivoted in the head of said bolt to selectively engage the steps of the ladder whereby the risers and struts are held in adjustment.

5. A step ladder comprising a pair of risers having treads'therebetween, brackets on the of said risers, a casing upper rear portions having pintles rotatable in said brackets, a pair of struts pivoted independently in said casing to swing towards and onsaid casing, said bar, links pivoted to said struts and engaged by said bolt at their inner ends, a'

' manually operable nut on said bolt to clamp rations in their rear central portion, rigid means to control the angular movement I ment said means said links when said struts arewin an ad justed position, and bolt, cooperative with said treads to retain said risers and struts in angular adjustment.

6. A step ladder having parallel risers and struts pivoted thereto bent'portion to engage selectively in'opening in certain of held in difierent adjusted flexible connection between said struts and risers limiting the angle therebetween, said struts being foldable against the ladder treads when the ladder is collapsed.

positions, and a s 7 A step ladder having fixed risers and a pair of struts,

said struts beingpivoted to present opposed angular inclinations with respect to each other and to move as a unit with respect to said risers, treads fixed be: tween said risers, said treads having perfoa single between said struts and risers, said means being selectively engageable in the perforations of said treads, and a flexible means to limit the ultimate movement therebetween.

8. A step ladderhaving fixed risers and'a pair of struts,.said struts having connections permitting limited lateral angular movey from each other, a down reaching slotted platebar fixed. I a bolt slidable in the slot of I means carried by said to move angularly with respect to each other and to swing as a unit relatively to the risers,

said struts said rod having a right angularly 1 a rod pivoted to the risers whereby they may be r

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