Folding ladder

United States Patent uu 3,554,318

<td> [72]</td><td> Inventor</td><td> Hugh P. Knight H.P. Knight Limited, East Street, Portslade, Sussex BN41EN, England</td>

<td> [21]</td><td> Appl. No.</td><td> 783,360</td>

<td> [22]</td><td> Filed</td><td> Dec. 12,1968</td>

<td> [45]</td><td> Patented</td><td> Jar 12,1971</td>

<td> [32]</td><td> Priority</td><td> Dec. 13,1967</td>

<td> [33]</td><td></td><td> Great Britain</td>

<td> [31]</td><td></td><td> No. 56636/67</td>

[56] References Cited

UNITED STATES PATENTS

1,014,215 1/1912 Forndran...................... 182/163

1,685,632 9/1928 Hammond.................... 182/24

3,073,414 1/1963 Lavrard........................ 182/24

3,143,185 8/1964 Wenger........................ 182/24

Primary Examiner— Reinaldo P. Machado Attorney—Linton &amp; Linton

[54] FOLDING LADDER

Claims, 13 Drawing Figs. [52] U.S.C1........................................................ 182/24, ' 182/27,182/163

[51] Int. Cl......................................................... E06c 1/10

[50] Field of Search............................................ 182/24,27,

163, 164,23,22

ABSTRACT: A folding ladder comprises a plurality of ladder sections which are connected together in end-for-end relationship by coupling means and in which at least two of the coupling means are hinge devices, the axes of all the hinge devices being located on the same side of the plane of the ladder, the arrangement being such that when the ladder sections are in alignment, adjacent end portions of adjoining ladder sections or hinge devices are in abutting relationship with one another.

<img file="US3554318A_D0001.tif" />

PATENTED JAN 121971

SHEET 1 OF 4

3,554,318

<img file="US3554318A_D0002.tif" />

ATTORNEY-S

PATENTED JAN? 2 ®7l 3,554,318 . SHEET 2 OF 4

<img file="US3554318A_D0003.tif" />

INVENTOR

HUGH PERCIVAL KNIGHT by n ' ' -a £&gt;

ATTORNEYS

PATENTED JAN 121971 3,554,318

SHEET 3 OF 4

<img file="US3554318A_D0004.tif" />

<img file="US3554318A_D0005.tif" />

<img file="US3554318A_D0006.tif" />

<img file="US3554318A_D0007.tif" />

46 50

INVENTOR

HUGH PERCIVAL KNIGHT

<img file="US3554318A_D0008.tif" />

ATTORNEYS

PATENTED JAN 1219?ι

SHEET U OF 4

<img file="US3554318A_D0009.tif" />

HUGH PERCIVAL KNIGHT

<img file="US3554318A_D0010.tif" />

ATTORNEYS

3,554,318

2

FOLDING LADDER

This invention relates to folding ladders, and is particularly concerned with a folding ladder which may be used in any one of a variety of different configurations.

Known ladders of the kind which can be used in a variety of sections configurations suffer from the disadvantage that they consist of a number separate sections which have to be secured together in the desired configuration.

It is an object of the present invention to provide a folding ladder in which this disadvantage is overcome.

According to the present invention, there is provided a folding ladder which comprises a plurality of ladder sections which are connected together in end-for-end relationship by coupling means, and in which at least two of the coupling means are hinge devices, the axes of all the hinge devices being located on the same side of the plane of the ladder, the arrangement being such that when the ladder sections are in alignment, adjacent end portions of adjoining ladder sections or hinge devices are in abutting relationship with one another.

Each hinge device may comprise two hinges, and each hinge may comprise two U-shaped members secured respectively around adjacent end portions of the stiles of adjoining ladder sections, the arms of one of the U-shaped members extending between the arms of the other U-shaped member and being pivotally coupled thereto.

Preferably, the stile of one of the ladder sections terminates within said one U-shaped member to define a socket therein, whereas the stile of the other latter section projects beyond said other U-shaped member for engagement in the socket when the ladder sections are in alignment.

A folding ladder in accordance With the invention will now be described by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of a house and illustrating various configurations that the folding ladder of the present invention is capable of achieving;

FIG. 1A is a view showing a further configuration of the folding ladder;

FIG. 2 is a perspective view of an end section and part of an inner section of the ladder;

FIG. 3 is a cross-sectional view through one stile of one section of the ladder as pivotally connected to one stile of an adjoining section of the ladder;

FIG. 4 is an enlarged detail view of part of FIG. 3;

FIG. 5 is a cross-sectional view taken along the line G-G of FIG.4;

FIG. 6 is a view showing the manner in which a plank is securable by clips to the inner sections of the ladder;

FIG. 7 is a view showing details of stay bars that assist in maintaining the various sections of the ladder in their desired relative dispositions;

FIG· 8 is a cross-sectional view through an end portion of a stay bar;

FIG. 9 is a cross-sectional view of an alternative device for securing together adjoining ladder sections;

FIG. 10 is a side view of a hinge incorporating a friction device for effectively securing adjoining ladder sections in alignment;

FIG. 11 is a cross-sectional plan view of part of the hinge of FIG.10;and

FIG. 12 is a perspective view of the Whole ladder with all its sections in alignment.

Referring to FIGS. 1 and 2, the folding ladder comprises two end sections and two inner sections coupled together in end-for-end relationship, the end sections 1 (FIG. 2) being jointed by hinges to the inner sections 2. In a first construction of the ladder, as shown in FIG. 12, the two inner sections are themselves hinged together by a further pair of hinges of the kind shown in FIG. 2. In a second, alternative construction, part of which is shown in FIG. 9, each end 40 of one of the inner sections carries a sleeve 41 which receives one of the ends 42 of the other inner section.

Referring now more particularly to FIG· 2, an end section 1 comprises two tubular stiles 3 interconnected by a plurality of transversely extending rods 4· Each rod 4 supports a transversely extending rods 5, the step 5 being prevented from rocking about the rod 4 by having its two ends let into slots cut in the stiles 3.

The lower end of each stile 3 is splayed outwardly, and the remote open end of each stile receive therein a foot 38 of any suitable nonslip material. Each foot 38 is wedged into its associated stile 3 and preferably terminates in a ground-engaging surface that is coplanar with the ground when the end section 1 is inclined relatively to an inner section 2 as illustrated in FIG. 2. The underface of the foot 38 may be ridged if desired.

The inner section 2 is of similar construction to the end section 1, except that the stiles 31 thereof are parallel with each other throughout their lengths.

The hinges jointing an end section 1 to an inner section 2 will now be described. Each stile 3 of the end section 1 extends through an outer clamp 6 that is of substantially Ushape. It will be seen from FIG. 2 that each stile 3 projects beyond its associated outer clamp 6 in the form of a projection 9. In a similar manner each stile 31 of the inner section 2 projects into an inner clamp 7 that is also of substantially Ushape, the side arms of the inner clamp 7 extending between the side arms of the outer clamp 6 and being pivotally coupled thereto by means of a pin 8. Each stile 31 of the inner section 2 terminates within its associated inner clamp 7 so as to leave a socket 10 therein, the socket 10 being of such configuration that when the end section 1 is swung into a position in which it is in alignment with the inner section 2, the projection 9 enters the socket 10 to ensure a rigid coupling between the inner section 2 and the end section 1. When the adjoining ladder sections are in alignment, the ends of the stiles 3 and 31 abut one another, so that a load acting from the opposite side of the ladder to the hinge axis, that is to say the axis of the pin 8, may be borne by the hinge without the need for any additional locking device.

As illustrated in FIG. 2, the clamps 6 and 7 may be riveted to their associated stiles 3 and 31, or alternatively, as illustrated in FIG. 3, the clamps 6 and 7 may be secured by bolts 11

Each end section 1 of the ladder may be secured in fixed angular relationship with its adjoining inner section 2 by means of stay bars 12, as shown in FIGS. 2 and 7. Each stay bar 12 consists of an elongated rod with bent over end portions 32 and 33, the two end portions extending parallel with one another, and perpendicular to the body of the stay bar. One end portion 32 of the stay bar 12 is pivotally mounted, in a bush 24, in one of the stiles 3 of the end Section 1. The other end portion 33 terminates in a shaped head portion 35, and also carries a metal coupling plate 25 which is rigidly secured to the end portion 33.

The head portion 35 of the stay bar 12 is shaped as shown in FIG. 8, for releasable engagement in a gripping device provided by an aperture in a resilient plate 27 of plastics material. The resilient plate 27 is secured behind an aperture 13 in the stile 31, the aperture in the resilient plate 27 being of smaller diameter than the aperture 13. The head portion 35 consists of a narrower neck part 36 and an enlarged terminal part 37, the aperture in the resilient plate being of slightly smaller diameter than the enlarged part 37 of the head portion. The enlarged part 37 can be pushed through the aperture against the resilience ofthe plate 27, and the stay bar 12 is locked in position by the plate 27 settling into place around the neck part 36 of the head portion 35.

A series of further apertures 13 (FIG. 2), each backed b a resilient gripping device, are provided along the stiles 31 in order to permit the end section 1 to be secured at different inclinations to the inner section 2.

Referring now to FIG. 1, there are shown a number of configurations of the ladder.

At A, the ladder is illustrated as a long ladder in which all the four sections are rigidly arranged in alignment.

3,554,318

By folding the upper end section out of the plane of the remaining three sections, the ladder can be used, as illustrated at B, as an eaves ladder in which the upper section is horizontally disposed, and the remaining three sections, which are rigidly arranged in alignment, are inclined slightly away from 5 the vertical.

By folding the upp&lt;- end section through 180°, relative to the inner section to wh’ch it is pivotally coupled, the ladder can be transformed to a short ladder as illustrated at C. At D the ladder is illustrated as a trestle, this arrangement being achieved by pivoting each end section downwardly relative to the two inner sections, which are maintained in alignment.

At E the ladder is illustrated as a step ladder by so folding the ladder that the two inner sections are inclined relative to each other, the end section associated with each inner section being in alignment therewith.

At F the ladder has been transformed into a stair trestle in that only one end section is inclined relative to the remaining sections, the remaining sections being supported at their other 2q end on a stair of a staircase.

In FIG. 1A the ladder is also in the form of a stair trestle formed by folding the two inner sections as shown, the end section associated with each inner section being in alignment therewith. This arrangement allows the ladder to be used 25 higher up the stairs.

When the ladder is used as a step ladder, two stay bars are connected together to provide a tie between the two sections. Referring to FIG. 7, one of the ladder end sections carries a stay bar 12 having a coupling plate 25 attached to it, while the 30 other end section (not shown) carries a stay bar 52 without a coupling plate. The stay bar 52 has a head portion shaped in the same way as the end portion 35 of the stay bar 12, and is releasably engaged by an aperture 54 in a resilient member 55 secured to the plate 25. The plate 25 has a larger aperture 56, 35 and the device functions in the same way as the device shown in FIG. 8.

When the ladder is to be used in any of the configurations shown in FIG. 1, or FIG. 1A, the free ends of the stay bars 12 and 52 are coupled either to their own stiles 3 of their end sec- 40 tions 1 as shown in FIG. 12, or to the stiles 31 of their associated inner sections 2, as shown in FIG. 2, as may be necessary according to the particular form of ladder required. Further stay bars are provided for interconnecting the two inner sections, in order that the configuration of FIG. 1A may ⁴⁵be achieved.

When the ladder is used as a trestle, a plank 20 may be secured in position between the stiles 31 (or 3) of the inner (or end) ladder sections, as shown in FIG. 6. The plank 20 has _θ secured to its underface a plurality of clips 21 having downwardly projecting ends 22. Each end 22 terminates in a lower portion 23 that is bent slightly to one side so as to form an end finger. One of these end fingers 23 will engage under a correspondingly shaped recess in one of the stiles 31, in a 55 manner sufficient to prevent inadvertent removal of the plank 20 from the ladder.

The trestle D of FIG. 1 may, of course, be inverted, and a plank supported at the desired height on corresponding steps 5 of the two end sections.

In order to assist in climbing up onto the horizontal portion of the ladder when it is used as a trestle, a removable handle H (FIG. 2) is inserted into the upper open end of one of the stiles 3. The handle H is of cylindrical form for the major part of its length, but is somewhat flattened at its lower end so as to be a 65 squeeze fit in the upper end of the stile 3.

If the two inner sections are joined by a pair of sleeves, as shown in FIG. 9, then it is possible to extend the length of the ladder by inserting an additional length of ladder (not shown) having a similar pair of sleeves at one end. In order to be able to use such a ladder as a step ladder, holes may be provided in all four ends of the stiles, to receive a long pivot pin or two shorter pins. The sleeves may be of generally U-shaped cross section and may function in a similar manner to the clamp 7 of FIG. 2. In these circumstances, the holes for receiving pivot pins may be provided in the projecting arms of the U-shaped sleeves.

A further configuration of the ladder may be achieved in the case where the inner sections are joined by sleeves. The two halves of the ladder are used separately as trestles to support a plank of desired length. The height of the plank may be adjusted by placing it on different steps of the trestles, or by varying the heights of the trestles themselves. This latter variation may be achieved by providing corresponding series of gripping devices along the stiles of the adjoining ladder sections, and securing the sections at the desired inclination by the use of stay bars with shaped heads on both end portions.

In order to make the ladder easier to manipulate once it is in its desired configuration, the hinges may be effectively prevented from folding by means of a locking device, or by means of a friction device. A locking device will now be described with reference to FIGS. 3,4 and 5.

FIG. 3 is an end view of one of the stiles 3 of an end section 1, when folded through 180° relative to the stile 31 of its associated inner section 2, there being a lock lever 14 associated with the two clamps 6 and 7.

Turning now to FIGS. 4 and 5 it will be seen that the pivot pin 8 has a central portion of enlarged diameter surrounded by a compression spring 15. The portion of enlarged diameter of the pivot pin 8 also extends through an aperture in the lock lever 14. The two sidearms of the U-shaped inner clamp 7 have apertures formed therein that are of less diameter than the enlarged central portion of the pivot pin 8, in order that said enlarged central portion of the pivot pin 8 shall present end shoulders that maintain the two sidearms of the inner clamp 7 in a spaced-apart condition. The ends 28 of the pivot pin 8, which are of lesser diameter than the central portion of the pivot pin, extend through corresponding openings in the sidearms of the inner clamp 7 as well as through corresponding openings in the sidearms of the outer clamp 6. The arms of the clamp 6 are spaced from the arms of the clamp 7 by washers 16.

It will be noted that the lock lever 14 is cranked somewhat, the cranked portion having an aperture through which extends a pin 17 that is secured to the two sidearms of the inner clamp 7. On the pin 17 is a washer 18, this washer 18 being between the lock lever 14 and the nearest adjacent sidearms of the inner clamp 7. By manually rocking the lock lever 14 in the direction of the arrow, a peg 19, on the lock lever 14, can be caused to retract from aligned openings in adjacent sidearms of the clamps 7 and 7. The openings in the sidearms of the clamps 6 and 7 are only in alignment when the end section 1 is in alignment with its associated inner section 2. Thus while an end section 1 is in the disposition relative to an inner section 2 as illustrated in FIG. 2, the peg 19 will not extend through the aperture in the outer clamp 6 but will only bear against the inner face thereof. As the end section 1 is swung into alignment with the inner section 2, the peg 19 will automatically slip through the aperture in the side arm of the outer clamp 6, as in FIG. 4, to lock the sections in alignment. The lock lever 14 is only associated with the clamps 6, 7 on one side of the ladder, such locking means not being necessary on both sides.

It will be appreciated that the clamps 6 and 7, the stay bars 12, and the locking lever 14 are also incorporated in the other end section 1, and also between the inner sections of the ladder when these are hinged together.

A friction device for retaining the ladder sections in alignment will now be described with reference to FIGS. 10 and 11.

Two clamps 46 and 47, of similar construction to the clamps 6 and 7 of FIG. 2, are secured to the ends of stiles 43 and 53 of adjoining ladder sections, and are pivoted on a pin 48. The stile 53 projects through the clamp 47 to form a projection 59, whereas the stile 43 terminates within the clamp 46 to leave a socket for receiving the projection 59.

Frictional engagement of the inside walls of the projection 59 is provided by a generally U-shaped member 44 which is mounted transversely within the stile 43 on the shanks of long rivets 45. The rivets 45 extend through the clamp 46 and stile

3,554,318 to secure them together. A compression spring 50 coiled around the shank of one of the rivets urges apart the two limbs of the member 44.

The end portions 51 of the limbs of the member 44 terminate in convergent portions which extend just beyond the ends of the clamp 46. As the stile 53 is moved around into alignment with the stl'e 43, the end portions 51 of the member 44 are forced inwardly, against the outward pressure of the spring 50, by the inside walls of the projection 59. The Ushaped member 44 accordingly grips strongly the inside walls of the stile 53. In this way, the ladder sections are effectively maintained in alignment to prevent folding of the ladder during manipulation thereof. In an alternative form of friction device (not shown) a gripping device secured to one of the clamps frictionally engages the outside surface of the other clamp.

The construction of the ladder having hinged inner sections may be folded at the center hinge to facilitate storage and transportation, or alternatively the two end sections may both be folded in. In the construction in which the two inner sections are connected together by sleeves, the two ladder halves may be separated, and each half-folded.