US1578529A - Ladder jack - Google Patents

Description

' March 30 1926.

C. E. KRAMER LADDER JACK Filed Oct. 4, 1921 v Patented Mar. 30, 1926.

,"UNITED STA S (man EK'V'KRAMYER, or CLE E AND, 01110, Assieivon'ro T E cnnvnnnivnwnonciir j;

PRODUCTS co rANY, orc EvnLAN oirro, 'nconronario v on OHIO.

LAnnnR Jack.

Application fileii October 4,1921. Q Serial No.-505,233..

To all whom itmag/ concern: 2

Be it known that I, CARL E, KRAME a citizen of the United States, residing at Cleveland-in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Ladder Jacks, of which the following is a full, clear, and exact description.

The present invention relates to what is termed-a ladder-jackand is intended to be usedin connection with a ladder for the purpose of-"supporting one end of a plank.

or platform. Y r I v Qneobject of the invention is to provide a ladder-jack in which the jack engages with and is secured .to illlQ'SldQ rails of a ladder rather than to the rungs. An additional object is to provide a ladder-jack in which the jack when attached to a ladder becomes substantially rigidly secured thereto. A fur ther object is to provide a jack which has four points of attachment to the'ladder in connection with which it is used so that if one side of the jack becomes disengaged it will still support the plank or platform which cooperates therewith.

Reference should be had to the accompanying drawings forming a part of'this specification in which Fig. 1 is a perspective view of a ladder and a jack mounted there on; .Fig. 2 is a top plan view of the jack with portions omitted; Fig. 3 is a top plan view of the upper part of the jack.

Referring to the drawings, 1 and 2 indi'-' cate side members which at their forward spect to the member-9 permits/the jack to wardly projecting ears which at their up-' per ends are spaced apart as indicated at 4* .to receive between them a pivoted bar 5. The ends of the side members 1 and 2 are pivoted on the side flanges of the base 4 At the opposite ends of the side members '1 and 2 there are secured U -shaped yokes 6 and 7 which are adapted to pass around the opposite side rails of a ladder. In order that the yokes 6 and 7 may properly engage with the side rails of the ladder, the members'l and 2 arebent at a slight angle as indicated at 1 and 2 and to this bent portion one side of each U-shaped yoke is and 2 from-moving away from the ladder when once'mounted thereon, atleastone of the'side membersis provided with a downwardly extending hook 8 which \vill'feXtend behind one ofthe rungs of the ladder and thus position and retain the side members against moving away from' the laddeiu The bar 5 extends through a slot which is formed ina member '9, which member has f pivotally secured to t, two diverging mem here 10 and 11. Thesemembers' 10 and .11 at theirouter ends are'provided with hook-f shaped portions which are adapted to ex T tend around the side rails of a ladder and to rest'uponione'ofthe rungs of the ladder; The bar '5 is provided with a plurality of notches 5 and the member 9 engages inthese slots and so' holds or supports the pivoted 7 ends of the side-members l and 2. I

These ladderjacksare-in practice used in pairs, eachjack' being mounted upon one of'a pair of ladders which are spaced apart. Between the jacks there extends a plat--.

form or plank. The side members land 2 are'adapted to receive and support one end of such a platform orplank.v 7 When the jack is used as abovedescribed the load on the platform'cr plank andthe" bending moments incident thereto are transmitted in large'part directly to theside rails of the ladder, which portions of the ladder are the strongest portions and will withstand greater stressesand strains than the rung of the ladder could possible stand.

The adjustability of the strap 5 with re be adjusted with respect to the ladder so as to have the side members 1 and 2 in a substantially horizontal plane and thus provide for different angular positions of the ladder With respect 'to the wall or smaller object against which the upper end of the ladder is I placed.

. Due to the pivoted construction the jack .may be completelyfolded so that when not in use it will occupy but a limited amountf of space.

It will be apparent that there canbe substantially no side sway to the'jack because when the side members land 2 are caused to engage with the side rails of the ladder and the books 8 pass over the adjacent round, the side members land 2 and the lad der form in effect a triangle and 'a stiff re- 1 sisting structure.

Additionallythe Urshaped members 6 and 7 engage with the side rails very'snugly' and therefore turning of the m'embersjfi and 7 on: the side rails of the ladder is prevented,

i Having-"described my invent-ionflfelaim'z -1. A"ladder-jaclrhaving'a pair of side members pivotally connected at one end which at the opposite free ends are provided with U-shaped engag mp;.rnembers adapted to engage the side'rails of a ladder, and also a with retaining neinbe-rs adapted; to engage V a rung of-aj ladder, a barlwhiclrispivotally :seonred; at the opposites.endsj'fofi said side members, a hook member Whl0-h lS 21dBJpi16d to-engagewvith the ladder, andco-operating means carried by the hook and said bar for adjusting the positionofthe hookwi'th re spect-to th'e'bar. i v 1' 2.- A; ladder-j ack comprisinga. pair ofi'si-de members pivotally connected at; their outer ends and having their inner free ends mov cable towerd and from-each otherysaid? mem-e hook members pivota-lly connectedi andadapted to engage with side rails. of a lad-,

hers are pi-votedatone or railengaging members ah t w opposite ends der and. means for adjustably connecting. said hooks to said bar. 7

3. A ladder-jack having a members, a support to hich'the side mem eir ends, ladder of the sidemembers, a bar pivotally secured to said support, said bar being provided with notches, a retainer member. having a slot through which said bar extends and having a portion adapted toengage witha;

pair of side selected notch, pivoted hook-members oarried by said retainer member, said-hook members being adapted to engage Wlijll the siderails of a ladder. f

4:. A ladder-jack having-g a-pair of side members, a support to Wlnchthe's1de members are pivoted at one of theirfe11ds, -U,-w

shaped-ladder rail engagingmembers Which are secnredsto the side members at the ends; a

' opposite to that at which theya-repivoted a ba-rpivotelly monntedjupon said sn-ppontif and provided with aplnrality ofnotchesya" retaining member adapted to cooperate with a selected notch inse-idi bar, hook members pivotally carried bythe retaining member,

l; hook members beingadaptedto engagewith the side rails of a ladder. 7

In vtestimony whereof I; hereunto afli-X- my signature, 1 r

CABLE. KRAMER

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