US3729063A

US3729063A - Telescoping ladder

Info

Publication number: US3729063A
Application number: US00219076A
Authority: US
Inventors: J Hein
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-01-19
Filing date: 1972-01-19
Publication date: 1973-04-24
Anticipated expiration: 1990-04-24

Abstract

An extensible ladder, consisting of a plurality of nesting telescoping channel sections, which can be telescopically extended, relative to each other. Each section, except the innermost, has a pivoted supporting dog which can be rotated inwardly so as to underlie and support the bottom rim of the next inwardly adjacent section. Each section has a plurality of vertically spaced pairs of opposite outwardly rotatable step bars which can be rotated to outwardly extending horizontal positions. The step bars are supported in outwardly extending positions on lugs provided on the sections or in notches provided in the top rim portions of the next subjacent sections. The lowermost section has a removable supporting base, having side struts whose top ends are engaged in slots provided near the top of the lowermost section.

Description

waited States Patent [191 1 [111 3,729,063 Helm [4 1 Apr. 24, 1973 TELESCOPING LADDER [76] Inventor: John E. Hein, l4 Cascade Drive, Primary E\'aminerReinaldo P. Machado R D 2 warren N J 07060 Attorney-Hyman Berman et al.

[22] Filed: Jan. 19, 1972 [57] ABSTRACT [21] Appl. No.: 219,076 An extensible ladder, consisting of a plurality of nesting telescoping channel sections, which can be telescopically extended, relative to each other. Each sec- [52] 11.8. C1. ..l82/l56, [82/189, ll8822/l29(;9, mm except the innermost, has a pivoted pp g l 1! Cu 1 I Q dog which can be rotated inwardly so as to underlie E281 F'g ld "5 L 1 5 6 1436 and support the bottom rim of the next inwardly ade o earc jacent section. Each section has a plurality of vertically spaced pairs of opposite outwardly rotatable step bars ,which can be rotated to outwardly extending horizontal positions. The step bars are supported in 182/195, 209, 21 l; 287/58 CT; 248/354 R, 354 S; 135/15 [56] References Cited outwardly extending positions on lugs provided on the UNITED STATES PATENTS sections or in notches provided in the top rim portions of the next subjacent sections. The lowermost section 2,052,439 8/1936 Bailey ..182/189 has a removable supporting base, having side struts 3,312,487 4/1967 M I tyr 7/58 CT whose top ends are engaged in slots provided near the 3,224,065 12/1965 Cheskin i ..182/146 top of the lowermost section 535,759 3/!895 Hill ....l82/209 1,024,380 4/1912 Vierheller ..182/210 11 Claims, 9 Drawing Figures I 2 Sheets-Sheet 1 fiHUrLrLrlLFlL E E E rpm- 1- Patented A ril 24, 1973 3,729,063

2 Sheets-Sheet 2 TELESCOPING LADDER This invention relates to extensible ladders, which can be collapsed to relatively small sizes, and more particularly to extensible ladders of the type having foldable laterally extendable step elements.

The main object of the invention is to provide a novel and improved extensible ladder, which is relatively simple in construction, which can be collapsed to a very small size, and which can be quickly and easily set up for use.

A further object of the invention is to provide an improved extensible ladder which is inexpensive to manufacture, which is durable in construction, which is safe to use, and which can be readily collapsed after use to a very compact size for easy transportation or storage.

Further objects and advantages of the invention will become. apparent from the following description and claims, and from the accompanying drawings, wherein:

FIG. 1 is a front elevational view of an improved extensible ladder constructed in accordance with the present invention, shown in its collapsed condition.

FIG. 2 is a front elevational view, to a smaller scale, of the ladder of FIG. 1 shown in its fully extended working position.

FIG. 3 is a side elevational view of the extended ladder, taken substantially on the line 33 of FIG. 2.

FIG. 4 is an enlarged fragmentary vertical cross-sectional view, taken substantially on the line 4-4 of FIG. 1.

FIG. 5 is a fragmentary enlarged vertical cross-sectional view, taken substantially on the line 5-5 of FIG.

FIG. 6 is a vertical cross-sectional view, taken substantially on line 6-6 of FIG. 5.

FIG. 7 is an enlarged fragmentary horizontal top plan view, taken substantially on the line 7-7 of FIG. 2.

FIG/8 is an enlarged fragmentary vertical cross-sectional view, taken substantially on the line 88 of FIG. 1.

FIG. 9 is a fragmentary vertical cross-sectional view taken substantially on the line 99 of FIG. 8.

Referring to the drawings, 11 generally designates a typical embodiment of an improved extensible ladder assembly according to the present invention. The assembly 11 comprises a supporting base plate 12, having .a pair of upstanding vertical parallel, generally triangular plate-

like flanges

13,13 rigidly secured tnereon substantially at its mid portion, as shown in FIG. 1. The apex portions of the

flanges

13,13 are connected by a transverse horizontal pin member 14. Designated at 15 is the outermost section of a plurality of nesting telescoping channel members, presently to be described, which can be telescopically extended relative to each other. The outermost channel member 15 has rearwardly extending

parallel side walls

16,16 which terminate in inturned

opposing retention flanges

17,17. The nestingly arranged plurality of inner telescoping channel sections are of similar cross-sectional shape and are shown at 18. The respective inner channel sections 18 are of progressively smaller size so as to be successively received within each other and within the outer channel section 15, as illustrated in FIG. 7.

' The

side wall

16,16 of the outermost channel section 15 are formed at their bottom end portions with parallel inclined slots 19. The member 15 is receivable between the pair of upstanding

vertical flange members

13,13 with the transverse horizontal pin member received in the slots 19 of channel member 15, as illustrated in FIG. 3.

The supporting plate member 12 may be of trapezoidal shape or rectangular shape, and is provided with a pair of upwardly and inwardly

inclined strut rods

20,20 supportingly engaged with the rear corner portions of plate member 12 and are provided at their top ends with inwardly projecting trunnion pin elements 21 which are slidably received through arcuate slots 22 provided in the upper end portions of the

side walls

16,16 of the outer channel member 15. Thus, the

struts

20,20 provide support against side sway of the ladder when it is in its extended condition and allow it to be adjusted through a substantial angle, for example, through an angle of from approximately to to the horizontal, namely, through an angle of approximately 30+ in a clockwise direction, as viewed in FIG. 3.

The

respective channel sections

15 and 18, with the exception of the innermost channel section 18 are provided at their top median portions with inwardly projecting stop blocks 23 which are engageable by outwardly projecting spaced pairs of

stop pins

26,26 provided on the bottom portions of the inwardly adjacent channel sections to limit extension of the channel sec tions relative to each other, namely, to prevent the sections from becoming disengaged from each other when the sections of the ladder are telescoped outwardly toward their fully extended positions.

The front walls of the

respective channel members

15 and 18 are each formed with a plurality of vertically spaced rectangular apertures 27, spaced at uniform distances vertically, for example, such that their bottom edges 28 are located at substantially one foot intervals. Pivoted at 29,29 to the front walls of the channel members below said aperture bottom edges 28 are' respective pairs of outwardly

swingable step bars

30,30 said bars being in substantially upright positions, as shown in FIG. 9, when the assembly is in its contracted inoperative positionjsuch as that shown in FIG. 1. When the channel members are in their extended positions, such as shown in FIG. 2, the step bars 30 may be swung outwardly toward substantially horizontal positions. For supporting the step bars in such outwardly extending horizontal positions, the front walls of the channel members are provided with respective supporting lugs 31 located so as to be engageable by the step bars 30 in their outwardly swung positions. At the top edges of the channel members, the side walls thereof are furthermore notched away, as shown in FIG. 5 at 32,32 to supportingly receive the

lowermost step bars

30,30 of the upwardly adjacent channel member 18. Thus, when the channel members are in their extended positions, the lowermost pair of

step bars

30,30 of each channel member can be supportingly received in the

notches

32,32 of the subjacent channel member in the manner illustrated in FIG. 5, and the remaining step bars of said channel member can be supportingly engaged on the supporting lugs 31 provided on the channel member in the manner illustrated in FIG. 2.

As will be readily apparent, the apertures 28 may be employed as foot-receiving apertures in climbing the ladder or alternatively, the

step bars

30,30 may be employed as the foot supporting means for climbing the ladder.

For supporting the bottom edges of the channel members when the ladder is in its extended position, all of the channel members except the innermost are provided with inwardly swingable pivoted supporting arms 33 which have a configuration similar to that illustrated in FIGS. 4 and 6, namely, which are formed with supporting right angled notches 34 which are supportingly engagable with the bottom edges of the inwardly adjacent channel members 18 when the supporting arms 33 are swung inwardly from the position shown in FIG. 4 to the position shown in FIG. 6. Thus, the arms 33 are pivoted at 35 to the associated channel members and are normally received in apertures 36 provided therefor in said channel members, being spring-biased in a clockwise direction, as viewed in FIG. 4, to engage in said apertures by the provision of biasing springs 37 coiled on the pivot pins 35 and having end portions bearing respectively on the inside surface of the front wall of the associated channel member and the adjacent bottom edge of the arm 33 in the manner illus trated in FIG. 4. Thus, in the normal positions of the pivoted arms 33, notches 34 are located at their upper right corner portions, and the members 33 may be pushed inwardly and rotated counterclockwise from the positions thereof shown in FIG. 4 toward the positions thereof shown in FIG. 6. The arms 33 have abutment shoulder portions 38 which abut against the inside surface of the associated channel member front wall when the arms 33 are rotated to the position shown in FIG. 6, whereas to limit clockwise rotation of the arms and to enable said arms to supportingly engage the bottom edges of the inwardly adjacent channel members 18. The

retention pins

26,26 are spaced apart sufficiently to provide clearance for the arms 33 when the channel members are extended in the manner previously described.

In using the device, when it is desired to set the ladder for use, the channel members are pulled outwardly toward extended positions, and the supporting arms 33 are successively pushed inwardly to the positions thereof shown in FIG. 6, to successively engage beneath the bottom edges of the inwardly adjacent channel members 18. By thus successively employing the arms 33 to engage beneath the bottom edges of the respective channel members, it is possible to extend the ladder assembly to its full length, for example, as shown in FIG. 2. Thereafter, the step bars 30 may be swung outwardly to their horizontal positions, shown in FIG. 2. As previously mentioned, the ladder may be adjusted to a suitable inclination, this adjustment being permitted by the sliding cooperation between the trunnion pin members 21 and the arcuately curved slots 22.

The channel members may be extended only partially, and may be supported by the arms 33, since said arms may be employed to supportingly engage beneath the top edges 40 of selected apertures 27 of the channel members, instead of engaging beneath the bottom edges 18 thereof. It is therefore possible to use the ladder in a partly extended position, namely, either with only several of the channel members in fully extended positions, or alternatively, with the inwardly swingable supporting arms 33 engaged beneath the top edges 40 of selected apertures 27 of the channel members. In operative position, the supporting arms 33 are held in their supporting positions, shown in FIG. 6, by the weight ofthe channel members.

When it is desired to collapse the extension ladder to its fully telescoped condition for transportation and storage, namely, the condition thereof illustrated in FIG. 1, the step bars 30 are first rotated inwardly to their substantially upright position, shown in FIG. 9, and the supporting arms 33 are allowed to return to their normal inoperative positions shown in FIG. 4, whereby to allow the channel members to be telescoped inwardly, namely. to restore the fully nested condition thereof shown in FIG. 1. A typical procedure for accomplishing this would be to first elevate the channel member 18 adjacent the lowermost channel member 15 sufficiently to allow the lowermost supporting arm 33 to slip past the bottom edge of the second channel member 18 under the biasing force of its associated biasing spring 37 and return to its normal position in its aperture 36, after which the second channel member 18 may be telescoped downwardly in the lowermost channel member 15 to its fully lowered position. This process may be successively repeated to allow the remaining channel members to be telescoped downwardly until the assembly is in its fully telescoped collapsed condition illustrated in FIG. 1.

It will be noted that the top edges of the aperture 36 are inwardly beveled to facilitate disengagement therefrom of their associated supporting arms 33 when said supporting arms are pushed inwardly. In their normal inoperative positions, shown on FIG. 4, supporting arms thus have outwardly projecting finger engagement lugs 41 defined beneath the substantially right angled notches 34 which project outwardly and therefore are easily manually engageable to push the arms 33 inwardly toward the operating positions thereof illustrated in FIG. 6.

As above mentioned, the strut rods 20 are provided to prevent side sway of the ladder when it is in its erected position.

The strut rods 20 may be either permanently affixed to the base plate 12 or may be detachably connected thereto, for example, the strut rods may be engaged in holes provided therefor in the rear corner portions of the base plate.

When extended, the ladder resembles a rectangular telephone pole with steps. When it is collapsed, it is relatively light and easily carried. It may be easily extended to a desired height or telescoped into a compact arrangement, as above described, for convenient storage in relatively small space. It is therefore a very useful accessory for emergency use.

It will be noted that when the foot bars 30 are extended to their horizontal positions, the lowermost foot bars 30 interlock with the subjacent sections by being engaged in the notches 32, as previously described. This interlock provides a substantial degree of rigidity in the connection between adjacent channel members, and aid in preventing lateral deviation of the adjacent channel members. The supporting arms 33, when in their operative positions, as shown in FIG. 6, prevent the sections from inadvertently telescoping downwardly.

As shown in FIG. 6, the support arms 33 are formed outwardly adjacent the right angled notches 34 with inclined edge portions 43 located so as to make flush contact with the bevels 36 of the associated support arm-receiving apertures when the support arms are in their non-supporting positions, such as shown in FIG. 4.

While a specific embodiment of an improved extensible ladder has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

l. Anextensible ladder comprising a plurality of elongated ladder sections telescopically engaging each other so that the sections can be extended from a collapsed telescoped condition to an extended condition, foot supporting means on each section, support arms pivoted to the sections so as to be swingable inwardly sufficiently to supportingly engage the inwardly adjacent sections, and means biasing said support arms outwardlytoward non-supporting positions wherein the inwardly adjacent sections can slide past the support arms, wherein said sections are formed with apertures and said support arms are received in said apertures when in said non-supporting positions, and wherein 'said support arms'are provided with stop shoulder elesupport arms are formed'with supporting notches opposite said stop shoulder elements, said supporting notches being located so as to face substantially up- I notches are substantially right-angled in shape.

4. The extensible ladderof claim 3, and wherein said arms have inclined edgeportions outwardly adjacent said notches; and said apertures have inwardly beveled top edge portions engageable by said inclined edge portionswhen the arms are in said non-supporting positions.

5. The extensible ladder of claim 4, and wherein said arms are provided inwardly adjacent said notches with upstanding lug elements which define outwardly projecting actuating elements for moving the arms inwardly when the arms are in said non-supporting positions.

6. The extensible ladder of claim 5, and wherein the sections are formed with longitudinally spaced substantially rectangular foot-receiving apertures.

7. The extensible ladder of claim 5, and wherein the sections have spaced front walls, and wherein said foot supporting means comprises outwardly swingable step bars pivoted to the front walls of the sections, the sections having notches in the sides of their top edge portions to supportingly receive the outwardly swung step bars ofthe inwardly adjacent sections.

8. The extensible ladder of claim 5, and wherein the sections have spaced front walls and each section is provided with the plurality of vertically spaced airs of opposite outwardly swingable step bars pivote to the front wall of the section and with supporting notches in the sides of its top edge to supportingly receive the lowermost outwardly swung step bars of the upwardly adjacent section, the section being provided with lug means to supportingly engage the remainder of its step bars in their outwardly swung positions.

9. The extensible ladder of claim 8, and wherein the ladder sections are generally channel-shaped and have inturned retention flanges on their rear edges.

10. The extensible ladder of claim 9, and a support ing base plate having a pair of upstanding parallel flanges spaced to receive the lowermost ladder sections therebetween, a transverse pin member secured between said last named flanges and spaced above the base plate, the sides of the bottom portion of the lowermost section being formed with parallel slots engageabl'e with andreceiving said pin member, and downwardly and outwardly. obliquely inclined strut rods connected to the sides of the top portion of the lowermost ladder section and supportingly engaged with the base plate rearwardly of said transverse pin mentsand the sides of the top portion of said lower- .most ladder section areforrned with arcute slots receiving said trunnion pin elements.

Claims

1. An extensible ladder comprising a plurality of elongated ladder sections telescopically engaging each other so that the sections can be extended from a collapsed telescoped condition to an extended condition, foot supporting means on each section, support arms pivoted to the sections so as to be swingable inwardly sufficiently to supportingly engage the inwardly adjacent sections, and means biasing said support arms outwardly toward non-supporting positions wherein the inwardly adjacent sections can slide past the support arms, wherein said sections are formed with apertures and said support arms are received in said apertures when in said non-supporting positions, and wherein said support arms are provided with stop shouldEr elements engageable with the inside surfaces of the sections below the apertures when the support arms are swung inwardly to their supporting positions.

2. The extensible ladder of claim 1, and wherein said support arms are formed with supporting notches opposite said stop shoulder elements, said supporting notches being located so as to face substantially upwardly when the stop shoulder elements engage the inside surfaces of the sections, whereby to define seats to supportingly receive portions of the inwardly adjacent sections.

3. The extensible ladder of claim 2, and wherein said notches are substantially right-angled in shape.

4. The extensible ladder of claim 3, and wherein said arms have inclined edge portions outwardly adjacent said notches and said apertures have inwardly beveled top edge portions engageable by said inclined edge portions when the arms are in said non-supporting positions.

7. The extensible ladder of claim 5, and wherein the sections have spaced front walls, and wherein said foot supporting means comprises outwardly swingable step bars pivoted to the front walls of the sections, the sections having notches in the sides of their top edge portions to supportingly receive the outwardly swung step bars of the inwardly adjacent sections.

8. The extensible ladder of claim 5, and wherein the sections have spaced front walls and each section is provided with the plurality of vertically spaced pairs of opposite outwardly swingable step bars pivoted to the front wall of the section and with supporting notches in the sides of its top edge to supportingly receive the lowermost outwardly swung step bars of the upwardly adjacent section, the section being provided with lug means to supportingly engage the remainder of its step bars in their outwardly swung positions.

10. The extensible ladder of claim 9, and a supporting base plate having a pair of upstanding parallel flanges spaced to receive the lowermost ladder sections therebetween, a transverse pin member secured between said last named flanges and spaced above the base plate, the sides of the bottom portion of the lowermost section being formed with parallel slots engageable with and receiving said pin member, and downwardly and outwardly obliquely inclined strut rods connected to the sides of the top portion of the lowermost ladder section and supportingly engaged with the base plate rearwardly of said transverse pin member.

11. The extensible ladder of claim 10, and wherein said strut rods have inwardly directed trunnion pin elements and the sides of the top portion of said lowermost ladder section are formed with arcute slots receiving said trunnion pin elements.