US3912043A

US3912043A - Pivoted extension ladder

Info

Publication number: US3912043A
Application number: US498386A
Authority: US
Inventors: James N Brannan
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-08-19
Filing date: 1974-08-19
Publication date: 1975-10-14
Anticipated expiration: 1992-10-14

Abstract

The specification discloses a pivoted extension ladder comprising two pairs of legs having two ends pivotally coupled together such that the legs may be pivoted between first and second positions to form a self-supporting ladder and an extended ladder respectively. Means is provided for releasably holding the two pairs of legs together in the first position when the ladder is being used as a self-supporting ladder. In addition, stop means is formed on the two pair of legs at their ends which are pivotally coupled together for engagement with each other when the two pair of legs are moved to their second position to prevent the two pair of legs from pivoting beyond the second position.

Description

[4 1 Oct. 14, 1975 United States Patent [191 Brannan PIVOTED EXTENSION LADDER ABSTRACT The specification discloses a pivoted extension ladder comprising two pairs of legs having two ends pivotally coupled together such that the legs may be pi [22] Filed:

. voted be- Appl' 498386 tween first and second positions to form a selfsupporting ladder and an extended ladder respectively. Means is provided for releasably holdin two pairs of legs together in the first ladder is being used as a self-suppo dition, stop means is formed on the tw their ends which are pivotally coupled gagement with each other when the two are moved to their second position to pre pair of legs from pivoting beyond the second position.

3 B l w m //1 22 21 88 8 ll P6 "n 2 4 S mm m m m 3 E mm WWQ m T m m 2 A "u 8 in. m" m 1 "m 5 mm m k l "H" Ar mu" rTha SCH m m0 mmmm E63 73 m& W89 2 H 0am usn &Ld I :I 88 UhF mw mum m mm 555 5 a Primary ExaminerReinaldo P. Machado 3 Claims 3 Drawing Figures PIVOTED EXTENSION LADDER SUMMARY OF THE INVENTION The object of this invention is to provide an economical, reliable, and easy-to-use extension ladder and which comprises two pairs of legs having two ends pivotally connected together such that the legs may be pivoted between first and second positions to form a selfsupporting ladder and an extended ladder respectively. Means is provided for releasably holding the two pairs of legs together in their first position and in addition, stop means is formed on said two ends of said two pairs of legs respectively and which are adapted to engage each other when said two pairs of legs are moved to their second position to prevent the two pairs of legs from pivoting beyond said second position.

In a further. aspect, the extension ladder comprises a first pair of legs joined by an upper cross piece at their top ends and by at least one cross piece at a position spaced from their top ends. In addition, there is provided a second pair of legs having first and second pposite ends. The second pair of legs are joined by at least one cross piece at positions spaced from their first ends. Means is provided for pivotally coupling said top ends of said first pair of legs and said first ends of said second pair of legs together to allow said first and second pair of legs to be pivoted, between first and second positions. Said first and second pair of legs at said first position form an acute angle relative to each other for forming a self-supporting ladder. Said first and second pair of legs at said second position form an angle of about 180 relative to each other for forming an extended ladder having an increased length for use for reaching greater heights. Means is provided for releasably holding said first and second pair of legs in said first position. In addition, stop means is provided on said first and second pairs of legs at their top and first ends respectively adapted to engage each other when said first and second pairs of legs are in their secondposition to prevent said first and second pairsof legs from pivoting beyond said second position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the extension ladder of the present invention when moved to its extended position;

FIG. 2 illustrates the extension ladder when located in its retracted position for forming a self-supporting ladder; and

FIG. 3 illustrates a modified arrangement for pivotally coupling together two ends of the two pairs of legs forming the extension ladder.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIGS. 1 and 2, the extension ladder is identified by reference numeral 21 and comprises a first pair of

legs

23 and 25 and a second pair of

legs

27 and 29. Legs 23 and 25are joined together at their

top ends

23A and 25A by an upper cross piece 31 and at partially folded or retracted position, the two pair of legs form an acute angle relative to each other and the ladder becomes a self-supporting ladder. In this position, the legs are held together by

hooks

45 and 47 and

eyes

49 and 51.

Hooks

45 and 47 are pivotally connected to

legs

23 and 25 respectively, by members 53 and 55 (not shown). It is noted that the

cross pieces

31, 33 and 35 are flat members which are connected between the

legs

23 and 25 at angles such that they in effeet-form level surfaces to allow one to step upward and to provide a better support when the ladder is being used as a self-supporting ladder.

The pair of

legs

27 and 29 may be pivoted to an extended position, as illustrated at FIG. 1 by removing the

hooks

45 and 47 from the

eyes

49 and 51 and swinging the

legs

27 and 29 upward in the direction of the arrow 56. In the extended position, the two pairs of

legs

23, 25 and 27, 29 are at an angle of about relative to each other. Connected to the top ends of

legs

23 and 25 are stops 57 and 59 which are adapted to engage

stops

61 and 63 formed at the

ends

27A and 29A of

legs

27 and 29 whereby when in the extended position, the two pairs of legs are prevented from pivoting beyond their 180 position. Thus, in the extended position, the pair of

legs

23 and 25 form the bottom portion of the ladder and the pair of

legs

27 and 29 form the top portion of the ladder and their ends 278 and 298 may be positioned against a wall or other object desired to be reached. The

cross pieces

41 and 43 preferably are round and they have no preferred angular position relative to the

legs

27 and 29 whereby when the

legs

27 and 29 are pivoted to the extended position, and the ladder is being used as an extended ladder, the user may easily step on the

cross pieces

41 and 43 at the proper angle. Thus, by making the

cross pieces

41 and 43 round, either pair of legs of the ladder in its selfsupporting position, may be used for stepping purposes, and the

cross pieces

41 and 43, when the

legs

27 and 29 are moved to the extended position, may be used also as stepping cross pieces.

In the preferred embodiment, the ladder is formed of aluminum. The

cross pieces

31, 33, and 35 are welded to the

legs

23 and 25 and

cross pieces

41 and 43 are swaged to the

lets

27 and 29, although they also could be welded.

Cross pieces

31, 33, and 35 are welded to

legs

23 and 25 at an angle such that they are level or nearly level when the ladder is being used as a selfsupporting ladder or an extended ladder. Both pairs of

legs

23, 25 and 27, 29 have right angled flanges to provide structural support. For storage purposes, when the ladder is not being used, the

hooks

45 and 47 may be unhooked from their

eyes

49 and 51 and the

legs

27 and 29 folded inward toward

legs

23 and 25 until the

legs

27 and 29 engage

stops

57 and 59 and hooks 45 and 47. In this position, the legs are folded together as faras possible forming a nearly flat folded ladder.

Referring to the embodiment of FIG. 3, there is illustrated a portion of one-half of the extension ladder showing two legs of each pair of legs. In this embodiment, the legs and stops, at their ends, are modified from that of the embodiment of FIGS. 1 and 2. Leg members 63, '65, and 67 are bolted together by bolts and

nuts

69 and 71 to form a leg 68 corresponding with leg 23 of the embodiment of FIG. 1.

Members

63 and 67 have enlarged,

rounded heads

63A and 67A formed at their top ends respectively. Member 65 has a stop or shoulder 65A formed at its top end and a concave surface 65B extending downward from the stop 65A. Thus, when the two

members

63 and 67 are bolted together with the inner member 65 sandwiched in between, an open space is formed between the two

heads

63A and 67A. The leg 73 corresponds with the leg 27 and has formed at its top end, an enlarged rounded head 73A which fits within the space formed between

heads

63A and 67A of

members

63, 65, and 67. A bolt 74 extends through apertures formed through

heads

63A, 73A, and 67A to pivotally couple leg 73 to the leg formed by

member

63, 65, and 67. The leg 73 has a stop 738 formed at its upper end, as illustrated in FIG. 3. The legs of the other half of the ladder are formed in a manner similar to

legs

68 and 73 and also are pivotally coupled together in a similar manner. Leg 73 and its mate (not shown) are fixedly connected together at positions spaced from their pivot ends by cross pieces, one of which is illustrated at 41. Leg 68 and its mate (not shown) are fixedly coupled together by cross pieces, two of which are illustrated at 31 and 33. The

cross pieces

31 and 33 are connected to the inner member 67 of leg 68 and to the corresponding inner member forming the mating leg of leg 68.

The legs 68 and its mate and 73 and its mate are adapted to be pivoted to a partially folded or retracted position and to an extended position similar to that shown in FIGS. 1 and 2. In the partially retracted position, hooks and eyes (not shown) are provided for holding the legs in their partially retracted position to allow the ladder to be self-supporting to be used for climbing purposes. When the ladder of the embodiment of FIG. 3 is to be extended, leg 73 and its mate are pivoted upward in the direction of the arrow 81 until stops 65A of leg 68 and its mate abut and engage stops 73B of leg 73 and its mate.

The ladder of the embodiment of FIG. 3 also may be formed of aluminum. Leg members 65 of leg 68 and its mate have a width less than the widths of

members

63 and 67 to allow leg 73 and its mate to be pivoted inward toward leg 68 and its mate to form a nearly flat and folded ladder for storage purposes when the ladder is not being used.

As one example of the ladder of the embodiments of FIGS. l-3, the ladder, in its folded or retracted position, may have a length of about two feet to form a short ladder and when extended forms a ladder of about four feet.

I claim:

1. A pivotal extension ladder comprising:

a first pair of leg means joined by an upper cross piece at their top ends and by at least one cross piece at a position spaced from their top ends,

a second pair of leg means having first and second opposite ends,

said second pair of leg means being joined by at least one cross piece at positions spaced from their first ends,

means for pivotally coupling said top ends of said first pair of leg means and said first ends of said second pair of leg means together to allow said first and second pair of leg means to be pivoted, between first and second positions,

said first and second pair ofleg means at said first position forming an acute angle relative to each other for forming a self-supporting ladder,

said first and second pair of leg means at said second position forming an angle of about 180 relative to each other for forming an extended ladder having an increased length for use for reaching greater heights,

means for releasably holding said first and second pair of leg means together in said first position,

stop means on said first and second pair of leg means at their top and first ends respectively adapted to engage each other when said first and second pair of leg means are in their second position to prevent said first and second pair of leg means from pivoting beyond said second position,

said first and second pair of leg means having outward facing sides facing in opposite directions when said first and second pair of leg means are in their first position,

said outward facing sides of said first and second pair of leg means facing in the same direction when said first and second pair of leg means are in their second position,

said first pair of leg means defining the bottom por' tion of said ladder when extended,

said upper cross piece having a generally flat upper surface located at an angle relative to said first pair of leg means such that said upper surface is generally level when said first and second pair of leg means are located in their first position and supported on a level base,

said stop means comprising:

a first pair of stops located on opposite facing sides of said first pair of leg means, and

a second pair of stops formed on said second pair of leg means for engagement with said first pair of stops when said first and second pair of leg means are in their second position.

2. The ladder of claim 1 wherein:

said first ends of said second pair of leg means straddle thetop ends of said first pair of leg means.

3. A pivotal extension ladder comprising:

a first pair of legs joined by an upper cross piece at their top ends and by at least one cross piece at a position spaced from their top ends,

a second pair of legs having first and second opposite ends,

said second pair of legs being joined by at least one cross piece at positions spaced from their first ends,

means for pivotally coupling said top ends of said first pair of legs and said first ends of said second pair of legs together to allow said first and second pair of legs to be pivoted, between first and second positions,

said first and second pair of legs at said first position forming an acute angle relative to each other for forming a self-supporting ladder,

said first and second pair of legs at said second position forming an angle of about relative to each other for forming an extended ladder having an increased length for use for reaching greater heights,

means for releasably holding said first and second pair of legs together in said first position,

each leg of said first pair of legs comprises an inner member and two outer members fixedly connected together such that said inner member is sandwiched between said two outer members,

the top ends of said outer members extend beyond the top end of said inner members such that a slot is formed between said two outer members at their top ends,

6 each leg of said second pair oflegs has its first end 10- said outward facing sides of said first and second pair cated in one of the slots of an associated leg of said of legs facing in the same direction when Said first first P of legs for Plvotal movement and second pair of legs are in their second position,

each leg of said second pair of legs has a stop means formed on its first end for engagement with the 5 inner member of its associated leg of said first pair of legs when said first and second pairs of legs are located in their second position to prevent said first said first pair of legs forming the bottom portion of said ladder when extended, I said upper cross piece having a generally flat upper surface located at an angle relative to said first pair and second pairs of legs from pivoting beyond said of legs such that said upper Surface generally second position, 10 level when said first and second pair of legs are losaid first and second pair of l g h outward f i cated in their first position and supported on a level sides facing in opposite directions when said first baseand second pair of legs are in their first position,

Claims

1. A pivotal extension ladder comprising: a first pair of leg means joined by an upper cross piece at their top ends and by at least one cross piece at a position spaced from their top ends, a second pair of leg means having first and second opposite ends, said second pair of leg means being joined by at least one cross piece at positions spaced from their first ends, means for pivotally coupling said top ends of said first pair of leg means and said first ends of said second pair of leg means together to allow said first and second pair of leg means to be pivoted, between first and second positions, said first and second pair of leg means at said first position forming an acute angle relative to each other for forming a self-supporting ladder, said first and second pair of leg means at said second position forming an angle of about 180* relative to each other for forming an extended ladder having an increased length for use for reaching greater heights, means for releasably holding said first and second pair of leg means together in said first position, stop means on said first and second pair of leg means at their top and first ends respectively adapted to engage each other when said first and second pair of leg means are in their second position to prevent said first and second pair of leg means from pivoting beyond said second position, said first and second pair of leg means having outward facing sides facing in opposite directions when said first and second pair of leg means are in theIr first position, said outward facing sides of said first and second pair of leg means facing in the same direction when said first and second pair of leg means are in their second position, said first pair of leg means defining the bottom portion of said ladder when extended, said upper cross piece having a generally flat upper surface located at an angle relative to said first pair of leg means such that said upper surface is generally level when said first and second pair of leg means are located in their first position and supported on a level base, said stop means comprising: a first pair of stops located on opposite facing sides of said first pair of leg means, and a second pair of stops formed on said second pair of leg means for engagement with said first pair of stops when said first and second pair of leg means are in their second position.

2. The ladder of claim 1 wherein: said first ends of said second pair of leg means straddle the top ends of said first pair of leg means.

3. A pivotal extension ladder comprising: a first pair of legs joined by an upper cross piece at their top ends and by at least one cross piece at a position spaced from their top ends, a second pair of legs having first and second opposite ends, said second pair of legs being joined by at least one cross piece at positions spaced from their first ends, means for pivotally coupling said top ends of said first pair of legs and said first ends of said second pair of legs together to allow said first and second pair of legs to be pivoted, between first and second positions, said first and second pair of legs at said first position forming an acute angle relative to each other for forming a self-supporting ladder, said first and second pair of legs at said second position forming an angle of about 180* relative to each other for forming an extended ladder having an increased length for use for reaching greater heights, means for releasably holding said first and second pair of legs together in said first position, each leg of said first pair of legs comprises an inner member and two outer members fixedly connected together such that said inner member is sandwiched between said two outer members, the top ends of said outer members extend beyond the top end of said inner members such that a slot is formed between said two outer members at their top ends, each leg of said second pair of legs has its first end located in one of the slots of an associated leg of said first pair of legs for pivotal movement therein, each leg of said second pair of legs has a stop means formed on its first end for engagement with the inner member of its associated leg of said first pair of legs when said first and second pairs of legs are located in their second position to prevent said first and second pairs of legs from pivoting beyond said second position, said first and second pair of legs have outward facing sides facing in opposite directions when said first and second pair of legs are in their first position, said outward facing sides of said first and second pair of legs facing in the same direction when said first and second pair of legs are in their second position, said first pair of legs forming the bottom portion of said ladder when extended, said upper cross piece having a generally flat upper surface located at an angle relative to said first pair of legs such that said upper surface is generally level when said first and second pair of legs are located in their first position and supported on a level base.