Technical area.

The present invention relates to a ladder with a first and a second side leg and a number of ladder rungs extending between said side legs, and a tilt protecting device comprising a ladder foot beam, which protrudes a distance beyond foot ends of the side legs and is hinged, partly to a bottom end of an extension leg which mainly extends along a bottom portion of the first side leg and is slidably mounted in a bracket attached to said first side leg, which bracket is provided with a clutch mechanism for locking the extension leg in desired positions, partly to the foot end of the second side leg.

Prior art.

A ladder of this type is priorly known from the Swedish patent specification SE 529879. The known ladder is provided with a clutch mechanism comprising a pair of locking rings in V-shape position which are stacked on the extension leg and are positioned between two protrusions on the bracket and which with outer edge portions that are positioned at the closest to each other are in contact with the surface of the extension leg, in addition to which the pair of locking rings are spaced apart by a compression spring between the pair of locking rings. This design permits a stepless adjustment and especially a reliable locking of the extension leg, stronger with increasing load, in both directions, which is necessary when the ladder on the ladder foot beam is pressed in one or opposite direction and, thus, the clutch mechanism is exerted to downward pressure or upward tension.

A drawback with the known ladder is, however, that a ladder cannot be used in a staircase standing on two different steps, because the ladder foot beam has to be detached from the ladder permitting it to stand on the extension leg and the foot end of the second side leg after adjustment of the protruding part of the extension leg. An obvious risk here is, however, that that the ladder foot beam will be lost after some time and cannot be found when it is needed again. One may then feel tempted to temporarily use the ladder without its foot beam in spite of the fact that a foot beam ought to be used, which of course constitutes a considerable risk.

Object of the invention.

The object of the invention is to achieve a ladder of the kind mentioned by way of introduction above, which can be used in staircases and on a similar support without the need of removal of the ladder foot beam from the ladder.

RECORD COPY-TRANSLATION

(Rule 12,4) Summary of the invention

The object of the invention is achieved by the fact that the ladder is characterized by the features stated in the independent claim 1, meaning that the connection of the ladder foot beam to the second side leg comprises a link with a means of attachment which is detachably attached to an anchorage in the side leg, which means of attachment is designed, after detachment from the anchorage and turning over of the ladder foot beam to a position along the extension leg, to be detachably attached alternatively to a corresponding anchorage in an upper end portion of the extension leg, and/or, as an alternative, that the connection of the ladder foot beam to the extension leg comprises a link with a means of attachment detachably attached to an anchorage in the extension leg, which means of attachment is designed, after detachment from the anchorage and turning over of the ladder foot beam to a position along the second side lag, to be detachably attached to a corresponding anchorage in the second side leg. Hence, it is possible, according to the invention, in cases when the ladder foot beam is a hindrance, in one single hand grip to detach one of the connections to the ladder foot beam and to fix the ladder foot beam along the extension leg or the second side leg. This may be carried out without problems with the adjustment of the extension leg. Then when the ladder foot beam is needed it is easily available and may be mounted on the ladder in one single operation.

The two mentioned attachment links are, according to a preferred embodiment, pivotally journalled in the ladder foot beam, and the mentioned means of attachment in the link comprises a threaded pin which extends into a threaded hole in the said anchorage and which is rotatably journalled in the connection link and is actuated by a twist grip. An anchorage with a corresponding threaded hole is arranged in an upper end portion of the extension leg or at a part of the second side leg at a fixed distance above its bottom end.

The connection between the ladder and the ladder foot beam is exposed to large stresses and has to be reliable. Hence, according to an especially suitable embodiment, the mentioned anchorage, between the second side leg and corresponding link belonging to the ladder foot beam, has a part-cylindrical elevated portion parallel to the side leg, and the upper and the bottom portions of the extension leg a cylindrical shape with the same diameter as the part-cylindrical elevation, which portions are adapted to get in contact with the link of the connection which in order to obtain an exact adaption to these portions is provided with a part-cylindrical recess through which the threaded pin of the means of attachment extends.

A further, preferred embodiment is characterized in that the extension leg is cylindrical and the ladder foot beam is pivotally attached to the bottom end of the extension leg with the threaded hole in the upper portion of the extension leg located in the pivoting plane of the ladder foot beam, so that the threaded pin of the means of attachment automatically will be guided to engage the threaded hole independent of the turning position of the extension leg.

An in practice suitable embodiment, that makes the operating of the link of the means of attachment possible without moving its twist grip to get jammed behind the ladder foot beam and being difficult to reach during the twisting, is characterized in that the connection link with its pin is turned over the upper end of the extension leg and is fit-up against the opposite side of the extension leg, where the threaded hole for attachment of the pin is positioned.

Brief description of drawings.

Two preferred embodiments of the invention are described in the following with reference to the attached drawings on which:

-Fig.l is a perspective view of a first embodiment of a ladder with a ladder foot beam;

-Fig.2 is a side view of the ladder in Fig.l with the foot beam adjusted for a laterally inclined support surface;

-Figs. 3,4,5 and 6 are perspective views of the ladder in Figs. 1 and 2 showing successive turning of the ladder foot beam to the position shown in Fig.6 for placing the ladder on the steps of a staircase;

-Fig.7 is a perspective view of the ladder in Fig.6 placed on the steps of a staircase;

-Fig.8 is a side view of a second embodiment of a ladder with a foot beam;

-Fig.9 is a side view of the ladder in Fig.8 with the ladder foot beam adjusted for a laterally inclined support surface; and

Fig.10 shows the ladder in Figs. 8 and 9 with the ladder foot beam adjusted for placing the ladder on the steps of a staircase.

Description of two preferred embodiments.

The ladders shown on the drawings are preferably light metal ladders of standard type provided each with a ladder foot beam of standard type mounted to the ladder foot ends by means of new holders in accordance with the invention.

Hence, Fig.l discloses a ladder with a first and a second side leg 1,2 and rungs 3 extending between the side legs. At the foot end of the ladder is a ladder foot beam 4 attached for self- ^• levelling purpose, which foot beam is acting as a lateral tilt protecting device. The first side leg 1 is on the outer side provided with a bracket 6 fixedly attached with screws 5, in which bracket a cylindrical extension leg 7 is slidingly journalled and arranged to be locked in wished positions by means of a clutch mechanism 8, quite in accordance with prior art disclosed by the patent specification SE529879 mentioned by way of introduction and disclosed more in detail in the following. The bottom end portion of the extension leg 7 is pivotally attached to the ladder foot beam 4 by a shoe 9 on the foot beam, and the bottom end portion of the side leg 2 has a link 10 which is pivotally attached to a shoe 11 on the foot beam 4. The link 10 is according to the invention easily and detachably attached by screwes to an anchorage 12a, as shown by the enlarged part, where the link 10 and the anchorage 12a are partly cut away in order to show a means of attachment 14f with a threaded pin 14 provided with a twist grip 13. The pin 14 extends through the link 10 and is screwed into a hole 15 provided with a corresponding thread in the anchorage 12a. The anchorage has a part-cylindrical shape and is parallel to the side leg 2. The link 10 has a part-cylindrical recess 16 that is fit-up against the anchorage 12a. Further, the pin 14 is provided with a nut 17 that prevents the pin 14 with the twist grip 13 from sliding out from the link 10 when the pin 14 is screwed out from the hole 15 for releasing the link 10 from the side leg 2.

With the ladder standing on a laterally inclined supporting surface is it necessary to displace the extension leg 7 to bring the ladder foot beam to bear on the support surface, as shown in Fig.2. This is carried out by releasing the clutch mechanism 8 by pressing together, against the action of a compression spring 18, two clutch rings 19 slidably mounted in V- position on the extension leg. Locking of the extension leg 7 is achieved at releasing of the clutch rings, as clearly described in SE 529879.

The lateral tilt protecting device in the shape of the ladder foot beam 4 is usually not applicable when the support surface consists of a staircase or similar support. In that case the link 10 is detached by using the twist grip 13 and then the ladder foot beam 4 is turned around as shown in Figs. 3 and 4 (dotted line) to the position shown in Fig.5 (showing a rear view of the ladder shown in Fig.4) disclosing the situation with the foot beam bearing on an edge of the exterior of the side leg 1, and with the link 10 turned over the end of the extension leg 7 to the position shown in Fig.6 where the link 10 is pressed with its part- cylindrical recess against the cylindrical surface of the extension leg, which forms an anchorage 12b in which a threaded hole 20 is located in the turning plane of the ladder foot beam 4, which threaded hole 20 is arranged to receive the threaded pin 14 with the twist grip 13 for attaching the link 10 to the anchorage 12b of the extension leg 7. By releasing the clutch mechanism 8 is it possible to place the ladder on a staircase during adjustment of the - extension leg 7 such that the end of the foot beam 4 provided with an anti-skid device gets in contact with a step of the staircase, as shown in Fig.7. Fig.8 discloses an embodiment of a ladder which easily may be adjusted for very large and very small differences in level, and is suitable as a ladder that is frequently moved, e.g. on a building site. The ladder has, as mentioned above, a cylindrical extension leg 7, which extends along the bottom portion of a first side leg 1, and is slidably journalled in a bracket 6 and locked by a clutch mechanism 8, as earlier described. The bottom end of the extension leg is provided with an anti-skid device 25 and is, moreover, pivotally attached to a ladder foot beam 4 by means of a link 22 of the same type as the link 10 described above in connection to Fig.l. The link 22 is provided with a threaded pin, which by a twist grip may be screwed into a threaded hole in an anchorage 12c formed by the cylindrical surface of the extension leg 7 (not shown). The second side leg 2 of the ladder is provided with a fixedly mounted frame member 24 into which a cylindrical guide bar 23 is slided and locked by a screw provided with a twist grip 26 and presenting a pointed end which protrudes into an annular groove (not shown) in the cylindrical surface of the guide bar. The guide bar extends along the bottom portion of the side leg 2 and is hinged to the ladder foot beam 4.

At positioning of the ladder on a sloping support with released clutch mechanism the ladder foot beam will be adjusted as shown in Fig.9, after which the clutch mechanism 8 is activated.

If the ladder has to be moved to a staircase the link 22 is detached from the extension leg 7, after which the ladder foot beam 4 is turned around and is applied against the guide bar 23 (dotted line) and the link in a manner described above in connection to Fig.5 is turned over the upper end of the guide bar 23 to fir-up against the opposite side of the cylindrical end of the guide bar, where an anchorage 12d with a threaded hole is located (not shown), into which hole the threaded pin (not shown) is arranged to be screwed for attaching the link 22 and accordingly the ladder foot beam 4 to the guide bar 23, as shown in Fig.10. The first side leg 1 of the ladder is supported by the displaceable extension leg 7, and the second side leg 2 is supported by the end of the foot beam which is provided with an anti-skid device. In this case it may happen that the level difference is large enough to make it impossible to be bridged over even if the extension leg 7 is displaced upwards as much as possible. Hence, the frame member 24 is preferably designed such that the guide bar 23 can be locked in two or more positions by the screw provided with a twist grip 26, e.g. by arranging further axially distributed grooves in the surface of the guide bar such that the guide bar 23 and accordingly the foot beam 4 can be displaced further downwards than shown on the drawing. It is of course possible to use the same clutch mechanism 8 that is used for locking the extension leg ^• 7 in the bracket 6 and which is shown identified by 28 in Fig.10. The invention is of course not limited to the here shown and described examples of embodiments but can be modified in various ways within the scope of the invention defined by the claims. This applies especially on the anchorages 12a-12d and the links 10, 22 with the means of attachment including a threaded pin 14, which may be replaced by other details serving corresponding purposes. It is, however, particularly desirable, that these details are designed to permit holding the ladder with one hand and detaching, turning and attaching of the ladder foot beam with the other hand without change of grip.