US2210803A - Extension ladder - Google Patents

Description

Aug. 6, 1940. s. E. DUNN EXTENSION LADDER Filed Aug. 25. 1958 Patented Aug. 6, 1940 easier.

Stanley E. Dunn, Montgomery, Pa

Application August 25, 1938, Serial No. 226,785

6 Claims.

This invention relates to an improved attachment for releasably. retaining a section of an extension ladder in an elevated position.

It is an aim of this invention to provide an apparatus for use with extension ladders adapted to be automatically actuated when released for retaining a section of the ladder in an elevated position and provided with means connected thereto for raising and lowering said section, said lo means being adapted to retract the ladder holding member and to hold it retracted while said section is being raised and lowered.

It is an important object of the invention to provide an apparatus of the aforementioned type which will be automatically actuated to lock the ladder section should the hoisting rope be accidentally released or break.

Still a further object of the invention is to provide a connecting member for sections of an ex- 29 tension ladder having a plurality of spaced integrally formed hooks each of which is adapted to cooperate in releasably engaging one of a plurality of ladder rungs for supporting one of said sections relatively to the other, and means con- 25 .nected to one of said hooks for normally retain- "ing the hooks in a projected position.

Other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawing, which eo illustrates a preferred embodiment thereof, and

wherein:-

Figure l is a front elevational View showing the invention attached to an extension ladder,

Figures 2, 3 and 4 are vertical sectional views taken on the lines 22, 33 and 44, respectively, of Figure 1, and

Figure 5 is a horizontal sectional view taken on the line 5-5 of Figure 1.

Referring more particularly to the drawing,

40 wherein like reference characters designate like or corresponding parts throughout the different views, Ill designates generally an extension ladder comprising the sections H and I2 which are held together by means of the members l3 which 45 are secured at their corresponding ends to the side rails of the section II and which are provided with the outwardly offset free ends I4 adapted to loosely engage the side rails of the section l2, and the members I 3' which are secured 50 at their corresponding ends to the side rails of section l2 with their free ends l4 bent to engage around the side rails of section H to cooperate with the members l3.

A connecting member l5, as best seen in Fig- 55 ure 1, comprises the two corresponding hooks wardly, as best seen in Figure 4, to form the eyenot,

let 23 therein. Hook 22 is in alinement with the hooks IQ, for a purpose which will hereinafter be explained. The opposite end of the shank 2!, which depends below the bar 29 is bent to form a hook 2 which projects in the opposite 15) '7 direction to the hook 22.

A spring 25 has its opposite ends 26 secured to the rung l8 and then coiled several times around the rung with its intermediate portion 27 extending upwardly to engage the hook 24 to urge the member i5 forwardly and downwardly or toward the rungs 28 of the ladder section ll. It will thus be seen that the hooks I9 and 22 will be normally urged into a position for engagement with one of the rungs 28.

One end of a hoisting cable 29 is secured to the eyelet 23, said cable extending upwardly therefrom and being trained over a pulley 39, which is secured to and depends from. the upper rung 2a of the ladder'section' H. Cable 29 then ex- 0 tends downwardly along the underside of the ladder section I l, around its lower rung 28 and then upwardly with its opposite end secured to the rung I8.

The operation of the extension ladder is as follows: by pulling downwardly on the portion of the cable 29 which extends along the underside of the ladder, member l5-will be swung upwardly and backwardly to a retracted position, against the action of the spring 25, with its hooks 40 I9 and 22 out of engagement with the rungs 28 and may be so held by the weight of the ladder section l2 so that section l2 may be hoisted by pulling downwardly on the intermediate portion 5 of cab-1e 29 or may be lowered by gradually paying out the intermediate portion of the cable. When it is desired to connect the hooks l9 and 22 to a particular rung 28 the ladder section I2 is hoisted by the cable 29 until the hooks I9 and 22 are slightly above the rung 28 and the cable 29 is then released suddenly so that the spring 25 will immediately project the member I 5 before the section [2 has a chance to drop so that when it begins to drop the hooks l9 and 22 will engage the desired rung 28 to retain the section l2 in the desired elevated position.

The ladder I if used at locations where the structures against which the ladder is to be 5 leaned have overhanging portions which the section [2 is to be hoisted past, the ladder I0 is inverted, from the position as seen in Figure 1, so that the section I2 is on the underside and so that the intermediate portion of the cable 29 is facing the operator who in hoisting the cable 29 to raise the section l2 may pull outwardly thereon to draw the ladder II], as a unit, from a diagonal position to substantially a vertical position so that the section I2 will move past the aforementioned overhanging projection.

Various modifications and changes in the construction and arrangement of the parts forming the invention may obviously be made and are contemplated, as the drawing and description are only intended to illustrate a preferred embodiment thereof, and the right is therefore reserved to make such modifications as fall within the spirit and scope of the invention as hereinafter defined by the appended claims.

I claim as my invention: 1. A device of the class described comprising a member including two hook elements, the shanks of said hook elements being adapted to be pivotally connected to the rung of a ladder section, 1a bar portion connecting said shank portions adjacent their hooked ends, a hook element formed integral with said bar and having an upwardly extending portion terminating in a bill provided with an eyelet and a downwardly extending por- -.:'tion, and spring means mounted on said ladder rung and engaging said downwardly extending portion to urge said hook elements forwardly and downwardly, the bills of said hook elements being adapted to normally engage rungs of a second ,;;l;aolder section to retain said first mentioned section in an elevated position.

2. A device as in claim 1, comprising means connected to said eyelet for raising and lowering said first mentioned ladder section, said means *.being operable to lift said member to raise the bills of said hook elements upwardly and backwardly and out of engagement with the rungs of said last mentioned section for moving said sections relatively to each other, said spring means uprojecting said bills when said last mentioned means is released.

3. An operating mechanism for extension ladders comprising a connecting member adapted to be loosely mounted on a rung of a ladder section, said member including a plurality of integrally formed hooks having spaced bills adapted to move as a unit to selectively engage rungs of another ladder section, the bill of one or said hooks being provided with an eyelet, means connected to said eyelet for raising and lowering said first mentioned ladder section and for retaining said hooks in a retracted position out of engagement with said last mentioned rungs, said last mentioned hook having a depending shank extending toward the first mentioned rung, and spring means connected to said first mentioned rung and. engaging said depending shank for projecting said hooks when said means is released.

4. An attachment for use with extension ladders, said attachment comprising a plurality of integrally formed hooks, certain of said hooks having depending portions adapted to loosely engage a rung of a ladder section, means carried by said rung and engaging the shank of another of said hooks for projecting said hooks as a unit, the bills of said hooks being adapted to selectively engage rungs of a second ladder section when in a projected position, and means connected to one of said hooks for retracting the hooks as a unit and for raising and lowering said first mentioned ladder section.

5. A latch member for extension ladders comprising spaced hook elements having shanks adapted to pivotally engage a rung of a ladder section, a cross bar having its ends formed integral with the intermediate portions of said shanks, a hook element formed integral with the intermediate portion of said bar and disposed transversely thereto, said hook elements each having their upper ends bent to form hooks adapted to selectively engage a rung of a second ladder section, and a spring carried by said first mentioned rung for engagement with the opposite end of said last mentioned hook element to project the latch.

6. A device as in claim 5, comprising a cable carried by said ladder sections, one end of said cable being connected to a portion of the hooked end of said last mentioned hook element for raising and lowering said first mentioned ladder section and for retracting said latch.

STANLEY E. DUNN.

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