EP0369256B1 - Hinge ladder - Google Patents

Abstract

The hinge ladder consists of two ladder elements (1) connected via a hinge (6). <??>On each ladder element (1), a telescopic ladder element (4) is mounted so as to be displaceable and it can be engaged by means of an engaging device (5) in order to be able to set different operating heights of the hinge ladder. <??>The hinge ladder can be used for all types of applications. <IMAGE>

Description

The invention relates to an articulated ladder with two ladder elements connected via joints, each comprising a plurality of rungs fastened to mutually parallel bars, a telescopic ladder element being mounted longitudinally displaceably and being height-adjustable on the ladder element by means of a latching device, the bars of the telescopic ladder element in each case lie against the outer sides of the spars of the ladder element and at least partially encompass them, furthermore the spars of each telescopic ladder element have an essentially U-shaped cross section, and wherein the latching device comprises at least one latching button which is displaceably mounted on the telescopic ladder element and in the front recesses of the rungs of the conductor element is insertable.

In known telescopic ladders, it has always been a problem to connect and secure the individual ladder elements of the telescopic ladder to one another. Therefor Various designs have been proposed, which include, for example, clamping elements or screw elements.

DE-A-3 446 255, which forms the closest prior art, shows a locking button which is slidably mounted on a spar of a conductor element. The locking button has a substantially U-shaped shape and is designed such that one leg is mounted on the conductor element is while the other leg of the U-shaped profile can be inserted into recesses of the second spar of the other conductor element. To use such a locking button, it is necessary that the two conductor elements are arranged essentially parallel to each other, since the two legs of the U-profile must be in engagement with a conductor element. This results in a decisive disadvantage, which is that, due to the distance between the respective spars required for moving the conductor elements, the connection by means of the locking button is not very stable. Furthermore, there is a risk that the locking button will be released by improper handling during use of the ladder, so that the ladder no longer has the required stability.

A similar locking element is known from US-A-4,376,470, here too the locking button is essentially in the form of a U-shaped element.

The invention has for its object to provide an articulated ladder of the type mentioned, which ensures a secure locking of the individual conductor elements with a simple structure and easy handling.

According to the invention the object is achieved by the combination of features of claim 1.

The invention is characterized by a number of significant advantages. The arrangement and storage of the locking button according to the invention ensures that malfunctions are excluded, since the spar of the outer conductor element engages around the spar of the inner conductor element and thus the locking button only has to be adjusted in one direction so that it engages with the spar of the respective one Conductor element can be brought. This achieves a high degree of operational safety, as tilting, tilting or similar can be completely excluded. Another significant advantage of the latching according to the invention is that it is particularly easy to manufacture, since the guide bush only has to be inserted into a recess in the spar; no welding work is required which could lead to a weakening of the material. The socket can thus be either permanently or detachably attached to the spar, so that there is the possibility, in particular in the case of universally usable conductors, of using the latching device at the desired point.

Further advantages of the articulated conductor according to the invention result from the dependent claims and the following description.

Since the telescopic ladder element used for the extension is in each case mounted on the ladder element according to the invention, it is possible to design the ladder element in the usual way, that is to say to equip a commercially available articulated ladder by means of the telescopic ladder element in such a way that it can be adjusted in height over a large height range. Furthermore, the strength of the conductor element of the articulated conductor is not influenced by the telescopic conductor element, since no attachments which weaken the conductor element are required. In addition, the two conductor elements can be connected to one another via a conventional joint.

According to the invention it is provided that the spars of the telescopic conductor element each bear against the outside of the spars of the conductor element and at least partially encompass the spars. The spars of the telescopic conductor element have an essentially U-shaped cross section. This design of the spars of the telescopic ladder element makes it possible to store them firmly and tilt-proof on the respective ladder element without the risk that the profiles of the spars and / or the rungs of the ladder element will be damaged, since a there is a large area of contact between the spars of the telescopic conductor element and the spars of the conductor element.

In order to reduce the manufacturing costs and to simplify the structure of the articulated ladder according to the invention, it can prove to be particularly favorable if the rungs of the telescopic ladder element are designed in the form of hollow profiles pressed together at their ends. With this configuration, it is not necessary to provide additional cover caps or the like at the ends of the rungs. Furthermore, the risk of injury is minimized since there are no or only insignificant edges. In a further development of the invention, it also proves to be particularly advantageous if the spars of the telescopic conductor element each have a longitudinal groove in which the ends of the rungs, i.e. the compressed end regions, are fastened. On the one hand, the rungs can be stored particularly securely, and on the other hand the end area of the rungs is encompassed, so that exposed sharp edges, which can lead to injuries, are avoided. Furthermore, in this embodiment it is possible to firmly connect the rungs to the respective spar by means of only a single weld seam. This measure on the one hand significantly reduces the manufacturing costs, and on the other hand it proves to be particularly advantageous for optical reasons to have to use only a single weld seam.

The latching device according to the invention comprises at least one latching button which is slidably mounted on the spar of the respective telescopic ladder element and can be inserted into the front recesses of the rungs of the ladder element. Since the rungs are usually designed in the form of hollow profiles which are inserted and flanged through recesses in the respective spars, there are already recesses available, which can be used for the locking device. Additional recesses, notches or the like on the bars of the conductor element are therefore not necessary. The conductor element is therefore not weakened by the attachment of the latching device. Furthermore, there is no risk that the profiles of the conductor element will be damaged. Since the latching button is also mounted on the spar of the respective telescopic conductor element, an optimal assignment of the latching device to the spar of the telescopic conductor element is always ensured, so that sufficient tipping safety is ensured.

The locking button comprises a bolt which can be locked in at least two different longitudinally displaced positions by means of a locking element. It is thus possible to lock the locking button in a locked state and in a released state. This avoids, on the one hand, that the latching device loosens itself during use of the articulated conductor and, on the other hand, it ensures that the telescopic conductor element can be displaced relative to the conductor elements of the articulated conductor without the locking button preventing the displacement inadvertently.

In a further, particularly advantageous embodiment of the articulated ladder according to the invention it is provided that a connecting element is mounted on the upper ends of the spars of at least one telescopic ladder element, which can be fastened to the upper end of the respective spar of the other telescopic ladder element. In this embodiment, it is possible according to the invention to separate the two telescopic conductor elements from the conductor elements and to connect them separately. The operator thus has the option of forming two double ladders each from the ladder elements connected by the joint and the two telescopic ladder elements connected to one another, over which a screed or the like can be placed in order to form a work scaffold. By being able to Separating telescopic ladder elements from the ladder elements of the articulated ladder, there is still the possibility of reducing the total weight of the articulated ladder if it is to be transported at a low required working height.

According to the invention, a connecting element in the form of a flap pivotably mounted on the respective spar is used to securely connect the two telescopic conductor elements, the free end of which is provided with a recess for carrying out the locking button of the respective other telescopic conductor element.

According to the invention, it is thus possible to use the latching buttons of the telescopic conductor elements to connect the two telescopic conductor elements by means of the connecting element. This embodiment has the advantage that damage to the profiles of the telescopic conductor elements is avoided, since the fastening points of the locking buttons, via which the force is applied, already have sufficient strength. Furthermore, it can prove to be advantageous if the upper end of the spar of the telescopic conductor element is provided with a slot-like recess for the passage of the tab. Since the location of the attachment of the tab is fixed, the slot-like recess can be designed such that it extends only over a small area of the total length of the spar. This does not affect the overall strength of the telescopic ladder element, but does, however, offer the possibility of creating specific contact surfaces for the tab in order to ensure that the upper regions of the bars are adequately stable. It should be pointed out in particular that the upper areas of the spars are not supported directly against one another, but rather against the locking button or the tab, respectively, so that damage to the profile of the spars is avoided.

The tab is preferably pivotable below the each associated locking button stored. Since the tab is pivoted upwards under load when the upper regions of the spars of the telescopic conductor element are connected, the tab comes into contact with the latching button or its bolt and is supported by the latter. This also avoids damage to the profile of the spars of the telescopic conductor element.

In order to be able to safely set up the articulated ladder according to the invention even on uneven ground, for example on stairs or the like, it can prove to be particularly advantageous that an extension strut is mounted at the lower end of the spar of the telescopic ladder element. It is thus possible to vary the length of each of the spars individually. The extension strut is preferably displaceable along the spar and can be locked by means of a locking device. It can prove to be advantageous to design the extension strut with a cross-section which corresponds approximately to the cross-section of the conductor elements, so that a firm hold on the spar of the telescopic conductor element is ensured.

In order to increase the security against tilting of the articulated ladder according to the invention, it can furthermore prove to be expedient to exhibit the lower ends of the spars of the telescopic ladder element laterally.

The articulated conductor according to the invention is, as described, constructed from simple, inexpensive to produce individual parts and is extremely simple to manufacture. All of this results in very low overall costs and an economical manufacturing option

With a corresponding design of the joint that connects the two ladder elements, it is possible to bring the two ladder elements from the rest position into an aligned position that is pivoted through 180 °, so that the articulated ladder according to the invention can be used as a single ladder is. A very large working height can be achieved by the telescopic ladder elements.

Figur 1

eine Seitenansicht der erfindungsgemäßen Gelenkleiter in einem betriebsbereiten Zustand

Figur 2

eine Seitenansicht der oberen Enden der miteinander verbundenen Holme der Teleskopleiterelemente

Figur 3

eine stirnseitige Ansicht auf die in Figur 1 dargestellte Gelenkleiter,

Figur 4

eine Schnittansicht entlang der Linie IV-IV von Figur 1

Figur 5

eine Detail-Seitenansicht gemäß der Blickrichtung V der Figur 1 und

Figur 6

eine Schnittansicht entlang der Linie VI-VI von Figur 1.

The invention is described below using an exemplary embodiment in conjunction with the drawing. It shows:

Figure 1

a side view of the articulated conductor according to the invention in an operational state

Figure 2

a side view of the upper ends of the interconnected spars of the telescopic ladder elements

Figure 3

3 shows an end view of the articulated conductor shown in FIG. 1,

Figure 4

a sectional view taken along the line IV-IV of Figure 1

Figure 5

a detailed side view according to the viewing direction V of Figure 1 and

Figure 6

a sectional view taken along the line VI-VI of Figure 1.

The articulated conductor according to the invention comprises two conductor elements 1, which are connected to one another by means of a joint 6 arranged at their upper end. The joint 6 is designed in the usual way and can be locked at certain pivoting angles.

The ladder elements 1 each comprise two spars 2, in which a plurality of rungs 3 are inserted. As can be seen from FIG. 4, the spars 2 have a rectangular cross section and are provided with square or square recesses into which the rungs 3, which are likewise designed in the form of a hollow profile, fit can be used. The outer ends of the rungs 3 are each fastened to the rungs 3 by means of a flange 18. The interior of the hollow profiles of the rungs 3 is accessible from the outside of the spars 2.

Telescopic ladder elements 4 are each mounted on the spars 2 of the ladder elements 1, each comprising two spars 7 and a plurality of rungs 8. The design of the telescopic conductor elements is described in more detail. The telescopic ladder elements can be moved along the ladder elements 1 and can be fixed in their respective positions by means of latching devices 5. The spars 7 each have a base 19 at the lower ends.

FIG. 4 shows a section along the line IV-IV of FIG. 1. It can be seen that the spar 7 of the telescopic conductor element has a substantially U-shaped cross section and encompasses the spar 2 of the conductor element 1 on three sides. A longitudinal groove 9 is formed on an outside of the U-shaped cross section.

The rungs 8 of the telescopic conductor element 4 are also in the form of a, preferably square, hollow profile and are squeezed at their ends so that the ends can be inserted into the longitudinal groove 9. The rungs 8 are fastened to the spar 9 by means of a weld seam 20.

A recess is formed on the side surface of the spar 7, into which a guide bushing 21 is inserted, in which a locking button 10 or its bolt 11 is mounted. The detent button 10 or the bolt 11 is slidably mounted in a guide bushing 21, which is designed as a cylindrical tube. The cylindrical tubular guide bush is inserted into a recess in the spar 7, as shown in FIG. 4. At one end, the guide bushing 21 comprises an annular flange, the outer diameter of which is larger than the inner diameter of the recess of the spar 7. Thus one-sided contact of the guide bushing 21 is ensured. The guide bushing 21, as can be seen in particular from FIG. 2, is provided with a groove 22 in which a latching element 12, preferably in the form of a wire-shaped spring element, is arranged. Two annular grooves 23, 24 are provided on the outer circumference of the bolt 11 of the locking button 10, the annular groove 24 being provided on the outermost end region of the bolt 11, while the annular groove 23 is formed on the region facing the locking knob 10. The annular grooves 23, 24 are designed such that the spring-like latching element 12 can be inserted into the annular groove 23 or 24 for latching the latching button 10. It is thus possible to lock the locking button 10 in the position shown in FIG. 4, in which it projects into the recess in the rung 3 and ensures a secure fixation of the telescopic conductor element relative to the conductor element. If the latching button 10 is pulled outward so that the latching element 12 engages in the annular groove 24, it is easily possible to move the telescopic conductor element 4 relative to the conductor element 1. It goes without saying for a person skilled in the art that the annular groove 22 can only extend over a partial region of the circumference of the guide bush 21 in order not to impair its strength.

In the embodiment shown, tabs 13 are mounted on the upper region of one telescopic conductor element, each of which can be pivoted about a pivot point 25. There is a tab on each side of the telescopic conductor element 4 13 provided. The free end of each tab is provided with a recess 14 which is dimensioned such that the bolt 11 of the locking button 10 of the other telescopic conductor element 4 can be passed through the recess 14. The fulcrum 25 is arranged below the assigned locking button 10, as shown in FIG. 2. By means of the tab 13, it is possible, when the telescopic conductor elements 4 have been removed, to connect their upper regions to one another, as shown in FIG. 2, in order in this way to be able to form a separate double conductor.

As shown in Figure 2, the spar 7 has at its upper end a slot-like recess 15 through which the tab can be pushed. In the ready-for-operation state, which is shown in FIG. 2, the tab 13 bears against the locking button 10 arranged above its pivot point 25 and against the wall of the recess 15, so that damage to the profile of the bars 7 is avoided.

As shown in FIG. 3, the lower ends of the telescopic conductor elements 4 can each be extended laterally in order to increase the stability of the articulated conductor according to the invention.

FIG. 6 shows a sectional view along line VI-VI of FIG. 1. In order to enable the articulated ladder according to the invention to be set up even on uneven ground or with stepped ground, for example on stairs, there are extension struts at the lower end of the spars 7 of the telescopic ladder element 4 16 mounted, which can be moved along the respective spar 7 and fixed by means of a locking device 17. The extension strut 16 has essentially the same cross section as the spar 2 of the conductor element 1, so that it can be firmly enclosed by the profile of the spar 7 of the telescopic conductor element 4. At the lower area of the telescopic conductor element, an elongated hole 26 is formed, in which a threaded bolt 27 is displaceable, which with a nut 29 is screwed, which can be biased against a pressure plate 28. The screw 27 is connected to a hand knob 30. By loosening the screw 27, it is thus possible to move the extension strut 16 together with the pressure plate 28 relative to the spar 7 and to fix it in the desired position.

The articulated ladder according to the invention thus makes it possible to move the telescopic ladder elements 4 relative to the ladder elements 1 by actuating the latching button 10 in order to vary the working height of the ladder in this way. Since the locking takes place by means of the locking buttons 10 on the rungs 3 of the ladder elements, it is ensured that, as shown in FIG. 1, the rungs 8 of the telescopic ladder elements are always assigned to the rungs 3 of the ladder elements 1, so that the operator is not disturbed unfavorable assignment of the individual rungs can take place. According to the invention, it is possible to push the telescopic conductor elements 4 completely onto the conductor elements 1 or to separate them completely in order to connect the telescopic conductor elements 4 to one another, as shown in FIG. 2, and in this way to have a separate double conductor available. By pivoting the joint 6, it is also possible to arrange the conductor elements 1 in alignment with one another, so that a high-rise instead of a ladder can be formed.

The invention is not restricted to the exemplary embodiment shown, rather a wide range of design options arise for the person skilled in the art within the scope of the claims.

Claims (13)

1. A hinged ladder with two ladder elements (1), which are connected via hinges (6) and each comprise a plurality of rungs (3) secured to stringers (2) which are parallel to one another, a telescopic ladder element (4) being mounted so as to be longitudinally displaceable on each ladder element (1) and being fixable by means of a locking device (5) to the ladder element (1) so as to be vertically adjustable, the stringers (7) of the telescopic ladder element (4) resting in each case against the outside of the stringers (2) of the ladder element (1) and enclosing the stringers (2) at least partially, furthermore the stringers (7) of each telescopic ladder element (4) having a substantially U-shaped cross section, and the locking device (5) comprising at least one locking knob (10), which is displaceably mounted on the telescopic ladder element (4) and can be introduced into the end face-side recesses of the rungs (3) of the ladder element (1), characterised in that the locking knob (10) is mounted on the stringer (7) of the respective telescopic ladder element (4) and comprises a bolt (11), which is longitudinally displaceably guided in a guide bushing (21), which is arranged on the edges of a recess in the base region of the U-shaped cross section of the stringer (7), the guide bushing (21) can be aligned by a displacement of the stringer (7) with the respective recess in order to allow for the introduction of the bolt (11) into the end face-side recesses in the rungs (3) of the ladder element (1), and the bolt (11) can be locked in at least one position by means of a locking element (12).
2. A hinged ladder according to claim 1, characterised in that the guide bushing (21) is constructed in the shape of a cylindrical tube and comprises an annular flange which rests against the inside of the stringer (7).
3. A hinged ladder according to claim 2, characterised in that the bolt (11) can be locked by means of a locking element (12) in at least two different, longitudinally displaced positions.
4. A hinged ladder according to one of claims 1 to 3, characterised in that the rungs (8) of the telescopic ladder element (4) are constructed in the shape of hollow profiles which are compressed at their ends.
5. A hinged ladder according to one of claims 1 to 4, characterised in that the stringers (7) of the telescopic ladder element (4) each comprise a longitudinal groove (9), in which the ends of the rungs (8) are secured.
6. A hinged ladder according to one of claims 1 to 5, characterised in that a connecting element is mounted in each case at the upper ends of the stringers (7) of at least one telescopic ladder element (4), which connecting element can be secured to the upper end of the respective stringer (7) of the other telescopic ladder element (4).
7. A hinged ladder according to claim 6, characterised in that the connecting element is constructed in the form of a bracket (13), which is pivotally mounted on the respective stringer (7) and whose free end is provided with a recess (14) for the introduction of the locking knob (10).
8. A hinged ladder according to claim 7, characterised in that the upper end of the stringer (7) of the telescopic ladder element (4) is constructed with a slot-like recess (15) for the introduction of the bracket (13).
9. A hinged ladder according to claim 7 or 8, characterised in that the bracket (13) is mounted beneath the respective locking knob (10).
10. A hinged ladder according to one of claims 1 to 9, characterised in that an extension strut (16) is mounted at the lower end of the stringer (7) of the telescopic ladder element (4).
11. A hinged ladder according to claim 10, characterised in that the extension strut (16) is displaceable along the stringer (7) and is lockable by means of a securing device (17).
12. A hinged ladder according to one of claims 1 to 11, characterised in that the lower ends of the stringers (7) of the telescopic ladder element (4) are laterally outwardly angled.
13. A hinged ladder according to one of claims 1 to 12, characterised in that the hinge (6) is pivotable through a range of approximately 180° so that the ladder can be used as a continuous long ladder, and can be fixed in this position and in intermediate positions.

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