US3315762A - Collapsible ladder - Google Patents

Description

April 25, 1967 s. s. TORREY 3,315,762

COLLAPSIBLE LADDER ,v I

Filed March 25, 1965 v 2 Sheets-sheaf 1 12219822303 SW83 '5. Toa fleg,

flfforaae y April 25, 1967 s. s. TORREY COLLAPSIBLE LADDER 2 Sheets-Sheet 2 Filed March 25, 1965 United States Patent The present invention relates to collapsible ladders and more particularly to collapsible ladders for use primarily as fire escape ladders in homes and buildings.

Various types of collapsible ladders have been developed for use as fire escape devices. Such ladders have experienced relatively small commercial success because of a number of individual undesirable features or disadvantages exhibited by each. Many have been unreliable because they were made of combustible materials or because they lacked stability in use. Some, designed as permanent fixtures for attachment adjacent a given window, have been cumbersome in addition to lacking portability which necessitated the use of a number of individual ladders to insure the existence of one where needed. Other such ladders have exhibited the serious disadvantage of being relatively complex in their operation. This is a serious drawback when one considers that during a fire a ladder user frequently is excited or near panic stricken.

The object of this invention therefore is to provide an improved collapsible sa-fety ladder which is extremely stable in use, is easily portable to any desired position, is extremely simple to place in an operating position, exhibits an attractive collapsed form, and is of relatively low cost construction so as to be within the economic reach of the general public.

One feature of this invention is the provision of a collapsible ladder having a plurality of ladder sections connected so as to permit substantial relative movement therebetween and wherein each ladder section has horizontal run-gs connected between crooked, vertical strut members which space the extended ladder assembly from a vertical contact surface.

Another feature of this invention is the provision of a collapsible ladder of the above featured type wherein the ladder sections are of uniform shape and are pivotally connected by links of such length as to permit nesting of the individual ladder sections in a parallel relationship upon contraction int-o a compact unit.

Another feature of this invention is the provision of a collapsible ladder of the above featured types including a pair of spaced parallel U-shaped members connected to the ladder sections and adapted to hook over a supporting edge and suspend the elongated ladder assembly therefrom.

Another feature of this invention is the provision of a collapsible ladder of the above featured types wherein the parallel U-shaped members are spaced by a distance greater than the normal width of the ladder sections enabling the collapsed ladder assembly to be compactly supported by and between the invented U-shaped members which function as a support stand.

Another feature of this invention is the provision of a collapsible ladder of the above featured types wherein the vertical strut members comprise substantially straight mid-portions supporting the transverse rungs and end portions bent at angles to the straight mid-portions so as to extend in divergent directions and provide the spacing between the extended ladder assembly and a vertical ladder support surface.

Another feature of this invention is the provision of a collapsible ladder of the above featured types wherein each pair of vertioal strut members is spaced by two transverse run-gs connected near the ends of the straight mid-pontions and extending through apertures therein.

Another feature of this invention is the provision of a collapsible ladder of the above featured types wherein the connecting links are pivotally connected to the transverse rungs and are of an equal length substantially the same as the spacing between the two rungs in each ladder section thereby allowing the ladder sections to be folded into a compact unit.

Another feature of this invention is the provision of a collapsible ladder of the above featured types wherein the angle between the end portions and mid-portion of each vertical strut are substantially equal and of a magnitude between 30 and 60 degrees thereby providing a compact folded unit while also providing when in use an adequate spacing between the extended ladder and a vertical ladder support surface.

These and other objects and features of this invention will become more apparent upon a perusal of the following specification taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective view of a preferred ladder embodiment shown in the collapsed position FIG. 2 is a front view in extended position of the ladder shown in FIG. 1;

FIG. 3 is an end view of the extended ladder shown in FIG. 2; and

FIG. 4 is a partial side View of another extended ladder embodiment according to the present invention.

Referring now to the drawings there is shown a collapsible ladder having a plurality of individual ladder sections 11. Each ladder section 11 includes parallel vertical strut members 12 each having a straight midportion 13 and end portions 14 divergently bent at uniform angles to the mid-portions 13. Each pair of strut members 12 is spaced and connected by a pair of transverse rungs 15 which pass through apertures 18 at each end of the straight mid-portions 13. Securing nuts 17 engage the threaded transverse rung ends which project through the apertures 18. Enclosing the transverse rungs 15 are the hollow cylindrical collars 16 which space the vertical struts 12 in a parallel relationship.

Pivotally connecting each pair of adjacent ladder sections 11 are a pair of parallel connecting links 19. The transverse rungs 15 pass through apertures 21 in each end of the connecting links 19 which lie between the inner surface of vertical struts 12 and the end surfaces of the cylindrical collars 18.

As shown in FIG. 2, an end rung of one end ladder section is pivotally connected to the attachment device 23 by end connecting links 20. The attachment device 23 (best shown in FIG. 1) includes the pair of inverted U- shaped members 24 which are joined by the connecting rod 25 and the support rod 26 which extend through apertures in the U-shaped members 24 and are secured thereto by nuts 27. Hollow cylindrical collars 28 also encircle the rods 25 and 26 and act as parallel spacers for U-shaped members 24. The connecting rod 25 passes through apertures in the ends of connecting end links 24 which lie between the U-shaped members 24 and the ends of cylindrical collar 28. The connecting end links 20 include two straight sections joined by angular sections 31 so as to be farther spaced at their points of pivotal connection with the connecting rod 25 than at their points of pivotal connection with the end rung of the end ladder section.

According to this arrangement the connecting rod ends of the links 20 are spaced by a distance slightly greater than the full width of the ladder sections 11. Thus with the ladder folded as in FIG. 1 the slightly projected ends of connecting links 20 provide ears 24a which align the entire folded ladder assembly evenly between the U-shaped members 24.

In the preferred ladder embodiment shown in FIGS.

1-3, the ladder sections 11 are uniform with each of the vertical strut members 12 being of identical shape. Also each of the connecting links 19 are of equal length which is substantially the same as the spacing 32 between link connections on each vertical strut 12. Thus the individual ladder sections 11 can be folded one on top of another in the compact nesting form shown in FIG. 1 with equivalent parts of each section 11 being substantially parallel. With this arrangement an escape ladder of adequate strength for its purpose can be constructed having, for example, a collapsed height H of about 7 inches for an extended length of 16 feet.

As shown in FIG. 1, the collapsed ladder unit is supported by the stand formed by the U-shaped members 24 with one end pivotally connected to connecting rod 25 and the other end supported by the support rod 26. This desirable arrangement is possible because the rods 25, 26 space the U-shaped members 24 apart by a distance greater than the width of the individual ladder sections 11. The folded ladder assembly shown can be conveniently stored in any desirable place with the ends of inverted U-shaped members 24 resting on a supporting surface.

At a time of desired use one merely lifts the ladder by grasping the top portions 35 of U-shaped members 24 which conveniently extend above the folded ladder assembly. The unit is then carried to the place of desired use and the connecting rod 25 end of the unit lifted over, for example, a window ledge 36 so as to hook the Ushaped members 24 thereon. A slight forward tipping of the unit will cause the folded ladder assembly to rotate around and over the connecting rod 25 with the entire assembly freely falling over the supporting ledge 36 to the extended ladder position shown in FIGS. 2 and 3. During this entire operation the handler maintains control of the ladder unit by holding the upper portions 35 of U-shaped members 24. Because the spacing between U-shaped members 24 is greater than the width of ladder sections 11 the operators hands and arms will not interfere with the projected movement of the unfolding ladder.

The ladder is secured by passing the open ends of U- shaped members 24 over so as to partially encircle the supporting ledge 36. This is easily accomplished since after removal of the ladder assembly the volume enclosed between the U-shaped members 24 is free of obstructions as shown in FIGS. 2 and 3.

The projection of the folded ladder assembly is made particularly easy by the arrangement of the support rod 26 which is connected to the U-shaped members 24 at a higher level than is the connecting rod 25. Thus the folded ladder assembly is supported in a forwardly inclined position allowing one to easily urge forward rotational movement of the assembly about the connecting rod 25.

With the ladder in the extended position shown in FIGS. 2 and 3 the ends of angular end portions 14 will rest against the vertical side surface 37 thus providing horizontal support for the ladder. Since the end portions 14 of the vertical struts 12 extend in a direction transverse to both the rungs and the elongated ladder they maintain a spacing between the side surface 37 and the rungs 15. This gives the user the extended space necessary for a secure footing on the rungs 15. For adequate horizontal rung spacing and a compact folded ladder assembly it is preferable that the angle A between the end portions 14 and the straight mid-portions 13 be between 30 and 60 degrees. The bearing direction of the end of end portions 14 against the side surface 37 at these angles also provides an extended ladder which is extremely stable.

Preferably, most of the ladder components such as the U-shaped members 23, vertical struts 12, horizontal rungs 15 and connecting links 19 are made of aluminum which offers good fire resistant properties, substantial mechanical strength, and light weight. The ladder shown in FIGS. 1-3, for example, can be made with a weight to extended length ratio of about one pound per foot.

FIG. 4 shows another preferred embodiment of the present invention which is'similar in most respects to the ladder shown in FIGS. 13. In this case however the rungs 41 pass through apertures in the ends of bent end portions 42 rather than through the ends of the straight mid-portion 43. Thus with the ladder extended the flat surfaces of the straight mid-portions 43 function as the bearing surfaces against vertical support surface 37. Again in this embodiment the mid-portions 43 extend a distance from the rungs 41 in a direction transverse to the rungs and the extended length of the ladder thus providing the desirable spacing between the rungs and the vertical surface 37. It will be understood that the ladder embodiment of FIG. 4 will assume a similar folded appearance to that of FIG. 1. However the bent end portions 42 will extend in an upward direction rather than in the downward direction taken by the end portions 14 of FIGS. l3.

Thus the present invention provides a collapsible ladder which is completely portable and which can be easily placed into an operating position. Also the adequate spacing and support from the vertical support surface provide the ladder with the stability necessary for a safe descent. Furthermore, and of great importance, the ladders unique mechanical configuration by minimizing production costs puts the ladder within the economic reach of a substantial percentage of the general public.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. For example, although described in connection with a preferred use as a fire escape ladder the utility of the invention for other applications will be obvious. These include, for example, uses with boats, manholes, towers, buildings, etc. It is therefore to be understood that within the scope of the attached claims the invention may be practiced otherwise than specifically described.

What is claimed is:

1. A collapsible ladder comprising a plurality of uniformly shaped ladder sections, each of said ladder sections including a pair of vertical strut members connected and spaced by at least one transverse rung, said ladder sections being connected together by connecting links positioned between each set of adjacent ladder sections and pivotally connected thereto so as to permit substantial relative movement between said ladder sections allowing contraction thereof into a compact unit and extension into an elongated ladder assembly, the length of said connect-ing links and the spacing between the two pivotal connections of said connecting links on each strut member being substantially equal so as to allow said uniform ladder sections to nest in substantially parallel relationship when contracted'into said compact unit, said vertical strut members having substantially straight mid-portions to which said transverse rungs are connected and end portions bent at an angle to said straight mid-portions so as to extend in divergent directions so as to permit nesting of said ladder sections in a compact side by side relationship, said strut member mid-portions and said transverse rungs, and attachment means connected to one of said ladder sections and adapted to permit suspension of said ladder from a supporting surface.

2. A collapsible ladder according to claim 1 wherein the ends of said connecting links are pivotally connected to the ends of said strut member straight mid-portions.

3. A collapsible ladder according to claim 2 wherein each pair of vertical strut members is spaced by two transverse rungs connected thereto near the ends of said straight mid-portions and said transverse rungs extend through apertures in the ends of said connecting links.

4. A collapsible ladder according to claim 1 wherein said end portions are each bent at substantially the same angle to said straight mid-portions, said angle is between 30-60 degrees, said transverse rungs extend through apertures in said strut members and including securing means for providing a tight connection therebetween.

5. A collapsible ladder comprising a plurality of ladder sections, each of said ladder sections including a pair of vertical strut members connected and spaced by at least one transverse rung, said ladder sections being connected together by connector means adapted to permit substantial relative movement between said ladder sections allowing extension thereof into an elongated ladder assembly and contraction into a compact unit, attachment means comprising a pair of rigid U-shaped members spaced apart by spacer means, said spacer means spacing said U-shaped members by a distance greater than the normal width of said ladder section so that upon contraction thereof substantially all of said compact unit will fit between said spaced pair of U-shaped members, one of said ladder sections being attached to one pair of adjacent legs of said spaced U-shaped members, mounting means connected to the other pair of adjacent legs of said U-shaped members and adapted to support said compact ladder unit thereon with the open side of said U-shaped members in a downward position, and wherein the volume between the legs of said U-shaped members is substantially free of obstructions thereby allowing said U-shaped members to partially encircle a supporting edge so as to suspend said elongated ladder assembly therefrom.

6. A collapsible ladder according to claim wherein said attachment means includes a handle portion extending above said compact ladder unit when supported within said U-shaped members, said spacer means comprise a connector rod attached to one pair of adjacent legs of said spaced U-shaped members and said mounting means comprises a support rod attached to the other pair of adjacent legs of said spaced U-shaped members, and wherein said support rod is at a higher level than said connector rod with the ends of said U-shaped members resting on a fiat support surface.

7. A collapsible ladder according to claim 5 wherein said attachment means includes a handle portion extend ing above said compact ladder unit when supported within said U-shaped members, said spacer means comprise a connector rod attached to one pair of adjacent legs of said spaced U-shaped members, and said mounting means comprises a support rod attached to the other pair of adjacent legs of said spaced U-shaped members.

8. A collapsible ladder according to claim 7 wherein said vertical strut members have substantially straight mid-portions to which said transverse rungs are connected and end portions bent :at an angle to said straight midportion so as to extend in a direction transverse to both said strut member mid-portions and said transverse rungs.

9. A collapsible ladder according to claim 8 wherein said connector means comprises a pair of connecting links positioned between each set of adjacent ladder sections and pivotally connected thereto.

10. A collapsible ladder according to claim 9 wherein said plurality of ladder sections are of uniform shape, and the length of said connecting links and the points of pivotal connection with said ladder sections are such as to allow said uniform ladder sections to nest in parallel relationship when contracted into said compact unit.

11. A collapsible ladder according to claim 10 wherein the ends of said connecting links are pivotally connected to the ends of said strut member straight mid-portions.

12. A collapsible ladder according to claim 11 wherein each pair of vertical strut members is spaced by two transverse rungs connected thereto near the ends of said straight mid-portions and said transverse rungs extend through apertures in the ends of said connecting links.

13. A portable ladder comprising a plurality of substantially uniformly shaped ladder sections including a pair of vertical strut members connected and spaced by at least one transverse rung, said ladder sections being pivotally connected by connecting links adapted to permit substantial relative movement between said ladder sections allowing extension thereof into an elongated ladder assembly and contraction into a compact unit, the lengths of said connecting links and the points of pivotal connection with said ladder sections are such as to allow said uniformly shaped ladder sections to nest in substantially parallel relationship when contracted into said compact unit, a stand attached to and adapted to support the compact unit formed by said contracted ladder sections, said stand being of greater width than the width of said ladder sections and including an attachment hook for supporting said portable ladder from a supporting edge, and wherein said attachment hook is adapted to permit attachment thereof to a supporting edge with said portable ladder contracted into said compact unit and supported by said stand.

References Cited by the Examiner UNITED STATES PATENTS 194,082 8/1877 Falk 182-164 412,752 10/1889 Hewitt 182-197 499,523 6/1893 Dobbs 182-163 806,706 12/1905 Buswell et al. 182197 1,177,557 3/1916 White 182164 REINALDO P. MACHADO, Primary Examiner.

Claims (1)

1. A COLLAPSIBLE LADDER COMPRISING A PLURALITY OF UNIFORMLY SHAPED LADDER SECTIONS, EACH OF SAID LADDER SECTIONS INCLUDING A PAIR OF VERTICAL STRUT MEMBERS CONNECTED AND SPACED BY AT LEAST ONE TRANSVERSE RUNG, SAID LADDER SECTIONS BEING CONNECTED TOGETHER BY CONNECTING LINKS POSITIONED BETWEEN EACH SET OF ADJACENT LADDER SECTIONS AND PIVOTALLY CONNECTED THERETO SO AS TO PERMIT SUBSTANTIAL RELATIVE MOVEMENT BETWEEN SAID LADDER SECTIONS ALLOWING CONTRACTION THEREOF INTO A COMPACT UNIT AND EXTENSION INTO AN ELONGATED LADDER ASSEMBLY, THE LENGTH OF SAID CONNECTING LINKS AND THE SPACING BETWEEN THE TWO PIVOTAL CONNECTIONS OF SAID CONNECTING LINKS ON EACH STRUT MEMBER BEING SUBSTANTIALLY EQUAL SO AS TO ALLOW SAID UNIFORM LADDER SECTIONS TO NEST IN SUBSTANTIALLY PARALLEL RELATIONSHIP WHEN CONTRACTED INTO SAID COMPACT UNIT, SAID VERTICAL STRUT MEMBERS HAVING SUBSTANTIALLY STRAIGHT MID-PORTIONS TO WHICH SAID TRANSVERSE RUNGS ARE CONNECTED AND END PORTIONS BENT AT AN ANGLE TO SAID STRAIGHT MID-PORTIONS SO AS TO EXTEND IN DIVERGENT DIRECTIONS SO AS TO PERMIT NESTING OF SAID LADDER SECTIONS IN A COMPACT SIDE BY SIDE RELATIONSHIP, SAID STRUT MEMBER MID-PORTIONS AND SAID TRANSVERSE RUNGS, AND ATTACHMENT MEANS CONNECTED TO ONE OF SAID LADDER SECTIONS AND ADAPTED TO PERMIT SUSPENSION OF SAID LADDER FROM A SUPPORTING SURFACE.

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