Ladders usable by people

Abstract

A ladder (1) that can be used by persons and is equipped with hollow rungs (4) open at both ends connecting two stiles (2) and has two casters (6) so that the ladder (1) can be moved on the ground for transport, wherein the casters (6) are supported by an axle (7) that penetrates one of the hollow rungs (4) and wherein the casters (6) can be moved from a position in use, in which they are intended to roll on the ground, into a position out of use and back again and can be locked in both the position in use and in their position out of use by means of a locking device (7) each, characterized in that the axle (7) with its two free end sections (8) is mounted in two retaining devices (9) and is screwed to the retaining devices (9) which are supported on the stiles (2), and that a locking device (11) is located on each retaining device (9),that a support element (15) carrying a caster (6) is arranged on each holding device (9) and that the support elements (15) are mounted on the holding devices (9) so as to be movable about a horizontal axis (13') and are connected to the locking devices (11).

Description

[0001] The innovation relates to a ladder usable by persons according to the preamble of claim 1.

[0002] Ladders of this type are known. The casters, attached directly to the ladders or via a retrofit kit, are designed to allow, in particular, heavy ladders to be transported by rolling them along the ground. Such ladders then no longer need to be carried in their entirety for transport. The known ladders and retrofit kits are equipped with retaining devices that support the casters. These retaining devices are either attached to the stiles supporting the hollow rungs or to the crossbar that runs transversely to the lower edge of the stiles and is designed to rest on the ground.

[0003] Document DE 1 801 409 U refers to a ladder in which the two casters are supported by a single axle.

[0004] Document EP 2 194 225 B 1 describes another ladder. On this ladder, the two casters can be moved from a working position, in which they roll on the ground, to a non-working position and back again, and can also be locked in place. To enable this, each caster is rotatably attached to one end of a rod-shaped support member. Each support member has a bore at its other end, each bore being designed to accommodate a manually operated tensioning screw. To attach these two assemblies to a ladder, an elastic expanding element is inserted into each of the two open ends of a designated hollow rung. Each tensioning screw is inserted through the bore of the respective support member and screwed into the expanding element associated with that screw.In this process, each spreader section is opened, causing each spreader element to be clamped to the hollow rung and the two casters to be connected to the ladder. By loosening the clamping screws, the support sections can be moved around the axis of the clamping screws to move them into or out of use. Thus, only a frictional connection is established between the spreader sections and the inner wall of the hollow rung. With rough handling of particularly large and heavy ladders, it is possible that the described frictional connection will not be sufficient to prevent one or more casters from coming loose under high forces.

[0005] The purpose of this innovation is to further develop a ladder of the type presented here in such a way that the casters are absolutely securely attached to the ladder. At the same time, it should still be possible to easily move the casters from a non-use position to a use position and back again.

[0006] The solution to the problem is described in the characterizing part of claim 1.

[0007] The decisive advantage of this innovation lies in the use of a single axle, which passes through a suitable hollow rung and is supported at its two free ends by a mounting bracket and bolted to it. Each mounting bracket is secured against rotation and supported on at least two angled planes on a stile. The axle's ends are threaded, allowing the axle to be bolted to the two mounting brackets, which are supported on the stiles, by means of a nut. When the ladder is moved over uneven surfaces, steps, depressions, or thresholds, particularly high forces occur, which are easily absorbed by the two mounting brackets and the axle and transferred to the stiles because the two mounting brackets are supported and bolted to the stiles.In contrast to the ladder described in document EP 2 194 225 B1, where one or both of the wheels, secured solely by friction, can easily come loose during rough handling, this is not possible with the novel solution found here, which is a significant advantage. The simple movement of the wheels from a non-use position to a use position and back again is also advantageously unaffected by the proposed solution.

[0008] The innovation will be explained in more detail using an example implementation. It shows Fig. 1 a ladder usable by persons in side view; Fig. 2 the same ladder in transport position; Fig. 3 a detailed view of the ladder with the casters in the operating position as well as Fig. 4 in a further detailed view a wheel in a non-use position.

[0009] All drawings are schematic.

[0010] Fig. Figure 1 shows a side view of a ladder 1 leaning against a wall, intended for use by people, which has two stiles 2 connected by horizontally arranged hollow rungs 4 in a known manner. In the lower section 5 of the ladder 1, two casters 6 are arranged in a known manner, which in this example are in a non-use position and therefore not in contact with the ground.

[0011] Fig. Figure 2 shows the same ladder 1, also drawn in side view. The ladder 1 is shown at a steep incline, as if it were being moved on the floor by a person using the two casters 6. The two casters 6 are thus in their operating position, meaning they are rolling on the floor.

[0012] Fig. Figure 3 shows the lower section 5 of the previously described ladder 1 in a front view. The drawing shows the ladder 1 together with the two stiles 2 and the last three hollow rungs 4. An axle 7 is inserted through the penultimate hollow rung 4. Bearing and locking elements 10 and 11 are attached to each end section 8 of the axle 7, which extends beyond the stiles 2 on both sides. Each bearing element belongs to a holding device 9. The two holding devices 9 are arranged as mirror images. A support element 15 is located on each holding device 9, with each support element 15 carrying a caster 6. The axle 7 is supported at its two end sections 8 in a bearing element 10 of each holding device 9.Each retaining device 9 rests against the outer side 3 of each of the two stiles 2 and is screwed to it from both outer sides with a nut 16, so that each retaining device 9, secured by the respective nut 16, not only rests against the outer side wall 3' of the stiles 2, but is also additionally supported against rotation by a shoulder 17 located on the retaining device 9, which runs perpendicular to the outer side wall 3' and is located on the narrow side 3' of the stiles 2 facing the casters 6, in such a way that the forces acting upwards from the casters 6 onto the ladder 1 when the ladder is moved are directly absorbed by the stiles 2. The retaining devices 9, which are screwed to the axle 7, are thus supported on both stiles 2 on two planes arranged at right angles.The locking device 11 located on each holding device 9 serves to move each caster 6 from an operating position to a non-operating position and back again. Each locking device 11 has a centrally arranged bore 13 to which each support element 15 is pivotably attached by means of a screw 18, see . Fig. 4. If the screw 18 is loosened slightly, each support element 15 can be moved around the centrally arranged bore 13 without loosening or breaking the connection between the axis 7 and the two retaining devices 9, see also Fig. 4. The adjustment process of the support parts 15 therefore does not affect, in contrast to the ladder according to EP 2 194 225 B1, the stable connection between the axis 7 and the two holding devices 9 in any way.

[0013] Another side view shows Fig. 4 a caster 6 in the non-use position. Shown is a section of a stile 2, a hollow rung 4 with an axle 7 located therein, the retaining device 9 arranged on the outer side wall 3' of the stile 2, and a support element 15, which is movably arranged on the retaining device 9 and has a caster 6 attached to it. The locking means 11 located on the retaining device 9 are formed by a ring of holes 12 arranged centrally to the bore 13, in the holes of which a spring-loaded pin 14, which is longitudinally movable on each retaining device 9, can engage, see also Fig.3. To move the casters 6 into a working or non-working position, simply pull the pin 14, which engages with one of the holes, out of the corresponding hole, pivot each support element 15 with the caster 6 attached to it about the horizontal axis 13' of the bore 13, and reinsert each pin 14 into the other hole corresponding to this position. The spring-loaded pin 14 remains in the corresponding hole, so that the casters 6 are locked in the desired position. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 1 801 409 U

[0003] EP 2 194 225

[0004] EP 2 194 225 B1 [0007, 0012]

Claims

[1] Ladder (1) which can be used by persons and is equipped with hollow rungs (4) open at both ends connecting two stiles (2) and has two casters (6) so that the ladder (1) can be moved on the ground for transport, the casters (6) being supported by an axle (7) which penetrates one of the hollow rungs (4) and the casters (6) being able to move from a position in use, in which they are intended to roll on the ground, into a position not in use and back again, and being lockable in both the position in use and in their position not in use by means of a locking device (7), characterized by, that the axle (7) with its two free end sections (8) is mounted in two holding devices (9) and screwed to the holding devices (9) supported on the beams (2), that a locking device (11) is located on each holding device (9), that a support element (15) carrying a caster (6) is arranged on each holding device (9), and that the support elements (15) are mounted on the holding devices (9) so as to be movable about a horizontal axis (13') and are connected to the locking devices (11). [2] Conductor according to claim 1, characterized by , that a shoulder (17) is provided on each holding device (9) which is intended to support the narrow side (3') of each beam (2) facing the casters (6). [3] Conductor according to claim 1, characterized by, that each locking device (11) is formed by a ring of holes (12) and by a spring-loaded pin (14) which is movable on each support part (15) and is designed to engage in the holes of the ring of holes (12).

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