US1906275A - Ladder jack - Google Patents

Description

C. E. KRAMER May 2, 1933.

LADDER JACK Filed Aug. 17, 1931 Arroemgfs.

Patented May 2, 1933 UNITED STATES teams Parent CARL n. KRAMER, of FAInvIEw VILLAGE, on o, Assienoa TO TH cLnvnn-aiin waouenr rnonucrs comrenxor cLnvnLei-inon o, A oonroe-Arron or onro;

LADDER JACK This invention relates to ladder jacks and is an improvement over my prior Patent No. 1,578,529 granted March 30, 1926.

The most important feature of the present invention resides in provision of a safety means whereby the probability of accident due to breakage, to persons using the ladder jack embodying the invention, is practically eliminated.

Another object of the present invention is to provide a ladder jack which is simple in construction, efiicient and inexpensive to manufacture.

Reference should be had to the accompanying drawing forming a part of this specification in which Figure 1 is a perspective View of a ladder and a ack mounted thereon;

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. 7

Fig. 4 is a fragmentary side elevational view on an enlarged scale showing the con struction embodying the present invention;

Fig. 5 is a top plan view of that shown in Fig. 4.

Referring to the drawing, 1 and 2 indicate side members which at their forward ends are pivoted as indicated at 3 upon a post 4. This post may conveniently be made as a sheet metal member which is folded upon itself to form a T-base 4 and has upwardly projecting ears which at their upper 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 1 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 1 and 2 are bent at a slight angle as indicated at 1 and 2 and to this bent portion one side of each U-shaped yoke is attached.

In order to prevent the side members 1 and 2 from moving away from the ladder whe o ce m u ed ther en; at l ast one of the-side members is provided with a downwardly extending hook 8 which will extend behind one of the rungs of the ladder and thus positionand retain the. side members against moving away from'the ladder. 1 f The bar 5 extends. through a slot which is formed in a member 9,.which member has pivotally secured to it, two diverging members 10 and .11. These members 10 and 11 at their outer ends are provided with hook shaped portions which are adapted to extend around the side rails .of aladder and to'rest upon one of the; rungs of the ladder- The bar 5 is provided witha plurality of notches 5? and the member 9 engages in these notches and, so holds or supports the pivoted ends of theside members land 2.

These ladder jacks are in practice used; in p pairs, each jaclr being: mounted upon one" of a pair of ladders which are spaced apart, Between the jacks there extends a platform or, plank. The side members 1. andf2 adapted to receive and support oneendot' such a platform or plank;

When the jack is used as above described the load on the platform or plan'k and the bending moments incident thereto are trans; mitted in largepart directly'to the side ralls oft-he ladder, which portions .of the ladder; arethe strongest portions and (will withstand greaterstresses and strains than the rung of the ladder couldpossibly stand.

The adjustability of the strap; spect to the member. 9 permits thej ack to be. adjusted with respectto; the ladder so as to? have the side members l and 2 in a substan-: tially horizontal plane and thus provide, for difierent angular positions of the ladder with respect-to therwall or smaller. object against which-the upper end ofthe ladder is placed.

5 with re Due to the pivoted construction the jac may be completelyfolded so that when not in use it will occupy but. a] limitedamount of.

space. V

7 It will be apparent that there can be sub,

' stantially' no side' sway to the jack because efiect a triangle and a stifi resisting structure.

Additionally the U-shaped members 6 and 7 engage with the side rails very snugly and therefore turning of the members 6 and 7 on the side rails of the ladder is prevented. I

In Figs. 4 and 5 there is illustrated the safety means embodying the present invention.

The pivoted end of the bar 5 is provided with an arcuate slot 13 in its underside within which is normally disposed the shank or body of a pin or rivet 12 which has its opposite ends rigidly secured to the projecting ears of the post 4. i It will, therefore, be readily seen that should the pivot at the end of the bar'5 become broken or otherwise accidentally disengaged, the end of the bar 5 and the post 4 will not become separated due to engage ment' between the pin 12 and the slotted portion of the bar 5, the load being taken by the .pin 12. This construction, therefore, provides a ladder jack which is practically safe, even though portions of the jack should become broken or accidentally disengaged.

While I have described the preferred embodiment of the invention, it is to be understood that I am not to be limited thereto inasmuch as changes and modifications may be resorted towithout departing from the spirit of the invention as defined by the appended claims. y

Having thus described my invention I claim: r i

1. A ladder jack comprising a pair of side members flexibly connected at one end so as to be relatively movable at the other, rail engag ingmembers associated with the free ends of said side members, a bar pivotally connected adjacent the connected ends of said side members, rail hook members adjust-ably connected with the free endof said bar, and interengaging means between the end of said bar and said side members and adapted to support'the side member independently of the bar pivot in casev of accidental dis-engagement.

2. A ladder jack comprising a pair of side members flexibly connected at one end so as to be relativelymova'ble at the other, rail engagingmembers associated with the free ends of said side members, a bar pivotally connected adjacent the connected ends of said side members, ,rail hook members adjustably connected with the free end of said bar,'and a pin and slot connection between the end of said bar and said side members and adapted signature. I

i CARL E. KRAMER.

to support the side member independently of- L the bar pivot in case of accidental disengagement. 7 I a '3. A ladder 1ack comprising a pair of side members, a'bracket to which said side mem-j bers are connected and having'a pair of spaced ears,er a1l engaging members asso: ciatedwith the free ends of said side meme

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