DE8512052U1 - Extension ladder - Google Patents

Description

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5722

Mr. Philipp Dieterle, Dipl.-Ing. (FH)

Burghaldenstr. 3 7239 Fluorn-Winzeln 1

Extension ladder

The invention relates to an extension ladder according to the preamble of claim 1.

With known extension ladders of this type, there is a risk that the rungs of the lower part of the ladder located in the openings of the hooks can accidentally come out of the hooks. This can cause a risk of accidents and also make transport and other movements of the ladder more difficult and also cause other disadvantages.

2g It is therefore an object of the invention to provide an extension ladder according to the preamble of claim 1, in which the risk of the hooks accidentally detaching from the rungs to which they are attached is avoided in a structurally simple, operationally safe manner.

This object is achieved according to the invention by a sliding ladder according to claim 1.

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This extension ladder provides increased safety against the risk of accidents due to the bolt(s) that automatically move into their locking position(s) and also enables the ladder to be transported without any problems in any position and location, as the

IQ latches, which keep the ladder sections locked in their parallel positions at the respective set ladder length, automatically move into their locking position or positions and thus this locking cannot be forgotten or omitted for other reasons, e.g. for convenience.

The bolt can preferably be designed as a rotary bolt or sliding bolt. According to a further development of the invention, it is particularly advantageous to secure the locking position of the bolt against unintentional unlocking, preferably by locking or locking its locking position, which ensures maximum security against unintentional unlocking.

The automatic transfer of the bolt into its locking position when placing the hook on a rung of the relevant lower ladder section can be particularly advantageous by the rung itself engaging the bolt

ir. moves to its locking position. This means that the automatic 30

Locking is completely position-dependent. This can also be achieved by having the bolt moved into its locking position by a return spring. It is also conceivable that in some cases the bolt can be allowed to move into its locking position by gravity if the automatic locking does not need to be position-independent.

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The drawing shows embodiments of the invention.

Fig· 1 a side view of a two-part extension ladder with a ladder fitting with a hook and a latch

according to an embodiment of the invention,

Fig. 2 shows an enlarged section of Fig. 1,

Fig. 2A is a partial section through Fig. 2 taken along section line 2A-2A,

Fig. 3 is a side view of a ladder fitting with a hook and a latch according to a

another embodiment of the invention, in which a rung of a ladder is also shown in dash-dotted lines,

Fig. 4 Views of the ladder fitting according to Fig. 3 and 5 seen in the direction of arrows M and N of Fig. 3.

Fig. 6 a partially cut section of a multi-part extension ladder with a ladder

fitting according to a further embodiment of the invention.

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The extension ladder 10 shown in Fig. 1 and 2 has two straight ladder sections 11, 11'. Each ladder section 11, 11* consists essentially in the usual way of two straight stiles (longitudinal stiles) 13 and 13', respectively, and these stiles 13 and 13* are connected to one another by rungs 14 and 14', respectively. The upper ladder section 11' fits with its stiles 13' with lateral play between the stiles 13 of the lower ladder section 11. The stiles 13' of the upper ladder section 11' can rest on the rungs 14 of the ladder section 11. These two ladder parts 11, 11' are adjustable in position relative to each other in the longitudinal direction to adjust the ladder length. In this case, at the upper end area of the bars 13 of the lower ladder part 11 \ there are additional guide tabs 12 for the bars 13* of the upper ladder part 11', which hold the upper ladder part 11' to the lower ladder part 11, but allow the upper ladder part 11· to tilt to a certain extent relative to the lower ladder part for the purpose of hooking in and out of hooks 15 arranged at the lower end area of the upper ladder part 11*.

In this embodiment, a hook 15 is arranged on the outside of the spar 13 of the upper ladder part 11', which is part of a fitting 16, which is here partially located in the narrow gap between the spar 13' that supports it and the adjacent spar 13 of the lower ladder part 11. At the same height, there is also a hook on the other spar 13 of the upper ladder part 13, which, if it is also part of a fitting 16, is also attached to the outside of the relevant spar 13'. If it is a hook without a latch, it can also be arranged on the inside of the relevant spar 13'. More hooks can also be provided, for example two more hooks at a rung spacing above the hook shown in Fig.1.

This hook 15 shown in Fig. 1 and 2 is part of a ladder fitting 16 formed by it, which, in addition to the hook 15, also has a latch 17, which

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is rotatably mounted on a bearing pin 20 attached to a plate J 9. The other hook(s) attached to the upper ladder part 11' can also be parts of a fitting, such as 16, according to Fig. In general, it is
completely sufficient and

advantageous to assign a latch 17 or one latch 17 each to only one or two of these hooks 15 of the ladder part 11'. The plate 19 also serves to attach this fitting 16 to the relevant longitudinal beam 13' by means of holes in the fastening elements penetrating it.

!5 rivets 21.

The hook 15 with plate 19 can be formed by a substantially flat, stamped piece of sheet metal. On the downwardly directed, free leg 22 of ^the hook 15, a locking and locking cam 23 is formed by stamping, which projects beyond the adjacent flat upper side of the leg and has the longitudinal section shown in Fig. 2A.

In the position shown of the latch 17, which is designed here as an approximately right-angled angle, it engages with a latch nose 24 under the rung 14 of the lower ladder part 11 on which the hook 15 sits with its upper crosspiece 25.

At the height of this rung 14 there is also a rung 14' of the upper ladder section.

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L 5 The bolt 17 can also be made of a flat sheet metal

% piece and thus also a cost-effective

The upper straight arm 26 of the bolt 17, which extends from the bearing pin 20 to the right, serves

as a handle for manually moving this bolt ^: - &iacgr;&ogr; into its unlocked open position and this arm 26 &iacgr; also cooperates with the locking and locking cam 23.

The function of this ladder fitting 16 is as follows:

In the position shown in Fig. 2, the latch 17 locks the upper ladder section 11' against sliding on the lower ladder section 11'.

y in such a pushing attempt the locking lug 24

comes to rest on the underside of the rung 14 and so the upper ladder part 11· can no longer be moved upwards. The opening 27 of the hook 15 is now so long that the rung 14 still extends through the hook opening 27 which is open at the bottom and so the hook 15 continues to secure the upper ladder part 11' against pivoting in the direction of arrow A relative to the lower ladder part. The upper ladder part is therefore held on the lower ladder part 11 by the guide tabs 12 and the hooks 15 and is also supported on the lower ladder part 11 by the hooks. This connection which holds the two ladder parts "M, 11· together cannot be accidentally released due to the latch 17, so that these ladder parts 11, 11* are held together safely by this connection and in particular cannot pivot relative to one another in the tabs 12. Rather,

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the latch 17 ensures the parallel position of the two ladder parts 11, 11' and thus the straight position of the ladder 10 for each set total length of the ladder 10. This total length can be adjusted step by step in the distance between the rungs 14.

This secure connection of the two ladder parts 11, 11' in parallel positions also facilitates the transport and positioning of the ladder and also reduces the risk of damage to the ladder 10, which could occur due to the hooks 15 becoming unintentionally unhooked.

In order to ensure that the bolt 17 is held securely in its locking position in any position of the ladder, its arm 26 in this locking position is opposite a locking surface 33 which is fixedly arranged on the U-shaped part 15 and is directed perpendicularly to the plane of the image. This locking surface 33 thus forms a stop for the bolt 17. The bolt 17 is securely locked in any position of the ladder by this locking surface when it is moved into its open position, in which it releases the hook opening 27 for inserting and removing the rung 14. This locking mechanism can only be released by hand - which provides the greatest possible safety - by moving the free end of the arm upwards perpendicular to the plane of the image so that this arm reaches the position shown in dash-dotted lines in Fig. 2 A. This possibility of movement of this arm 26 can be achieved by elastic design of this arm and, if necessary, also supported by the play of the pivot bearing of the bolt 17. This manual movement of the arm in the position shown in Fig. 2 A

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However, the dot-dash position still does not release the bolt 17 for maximum safety, because the arm 26, when you want to move it downwards in the direction of arrow B over the locking and locking cam 23, hits the top of the rung. To release the bolt 17, it is additionally necessary here that, when the bolt 17 has been manually moved into the dot-dash position according to Fig. 2A, the upper ladder part 11' is moved upwards and/or the lower ladder part 11 is moved downwards.

!5 and as a result the hook 15 moves upwards relative to the rung and the latch 17 can now be pivoted with increasing relative movement of the hook 15 by hand or by a tension spring (not shown) or gravity in the direction of arrow B until the latch nose 24 is released from the rung 14 and now the upper ladder part 11' can be moved completely upwards towards the lower ladder part 11 until the rung 14 has completely come out of the hook 15. The latch 17 is then in the open position (not shown), in which the latch nose 24 no longer overlaps the hook opening 27, but the upper latch arm 26 now overlaps this hook opening 27 in an upper area.

The latch 17 is secured in its open position by the locking and locking cam 23 against unintentional pivoting in its locking position, which facilitates the length adjustment of the ladder 10, with a stop 30 also stamped onto the leg 22 of the hook 15, which blocks pivoting of the latch in the direction of arrow B beyond the maximum open position.

t - t ·■ » ·

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The latch 17 can remain in this open position until the hook 15 is again placed on a rung J 4 of the lower ladder section 11. When this is done, the top of the relevant rung 14 hits the area of the arm 26 overlapping the hook opening 27 from below and thereby pivots the latch 17 into its fully extended locking position, so that the rung 14 is automatically locked in the fitting 16 with absolute certainty. In particular, this locking and the resulting locking of the upper ladder section 11' on the lower ladder section 11 against relative tilting of the ladder section 11' to the ladder section 11 and thus also against relative displacement of these ladder sections 11, 11' in the longitudinal direction to one another must not be forgotten.

This ladder fitting 16 therefore provides complete security for the automatic locking of the two ladder parts 1), 11' by means of the latch(s) 17 and against unintentional disengagement of the hook 5 from the relevant rung 14 and thus maximum accident safety and also particularly convenient transport of the ladder in any relative position of its two ladder parts 11, 11' to each other, since the straight position of the ladder 10 is ensured by the

Latch 17 is absolutely securely secured. 30

Instead of the locking and locking cam 23 shown, other means for securing the open position and locking position of the bolt 17 against unintentional adjustment can often be provided. For example, ° for particularly simple manual unlocking of the bolt 17, it can be provided that the bolt in

5722

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its locking position is held by a locking or frictional position which can only be overcome with considerable force. For example, in Fig. 2, instead of the locking and locking cam 23, the bolt 17 could be made stiff, for example by a corrugated, axially springy ring placed on the bearing pin between it and the plate 19, which rests with pre-tension on the bolt 17 and on the plate 19. This ring then forms a frictional position for both the open position and the locking position of the bolt 17, whereas the cam 23, in its capacity as a locking cam, forms a locking position for the open position of the bolt and, in its capacity as a locking cam, locks the locking position of the bolt 17. It can also be provided that the locking position of the bolt 17 is only secured by a locking position, for example, for this purpose the locking cam 23 can have an inclined surface 51 instead of the locking surface, as shown in dash-dotted lines in Fig. 2 Δ.

In Fig. 3-5, a ladder fitting 16 according to a second embodiment of the invention is shown, wherein in Fig. 3 a rung 14 of a lower ladder part, not shown in detail, is also shown in dash-dotted lines.

This ladder fitting 16 has two essentially flat sheet metal parts 17, 19'. The sheet metal part 17 forms the latch and the sheet metal part 19' has the hook 15 and the plate 19 for fastening this fitting 16 to a beam, preferably on its outside facing the adjacent beam of the other ladder part. If the movement of the latch 17 is prevented by the

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adjacent rung of its ladder section is not obstructed, the fitting 16 can also be attached to the inside of the stile.

This board 3 9 has four holes for screws, rivets, nails or the like for fastening it to a pillar of a ladder section.

The latch 17 is rotatably mounted on a bearing pin 20 attached to the hook 55 at the location shown in Fig. 2, which has a widened head 31 against which the latch 17 is pressed by means of a curved bending spring 32. In the axial direction, the latch 17 has a lot of play on the bearing pin 20, so that it can be tilted on it to a limited extent. On the free leg 22 of the hook 15, a locking and locking cam 23 is also formed by punching and embossing, which has the same function as the locking and locking cam 23 of the embodiment according to Figs. 1 - 2A.

In the fully extended position of the latch 17, it is in its open position, in which the opening 27 of the hook 15 is open for the insertion of the rung. The left-hand arm 26 of the angled latch 17, which also serves as a handle, overlaps the upper area of the hook opening 27 when the latch 17 is in the open position. This arm 26 projects laterally over the hook 15 for convenient handling. In its open position, this latch 17 is held against unintentional pivoting by the locking and locking cam 23 and a stop 30* forming an angled portion of the sheet metal part 19* for the area 35 of the latch 17. If this hook 15 is now placed ^on a rung 14 by a corresponding relative movement between the upper and lower ladder sections, then the rung penetrates the hook opening. 27 and, v/hen the rung 14 to the hook-

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Opening 27 overlapping area of the arm 26, this bolt 17 is now automatically pivoted by this rung 14 from the fully extended position shown to the dot-dash position. Here too, there is a guarantee that the bolt 17 cannot be forgotten to be moved up to its locking position. This dot-dash position of the bolt 17 corresponds to its locking position in which the hook 15 can no longer be removed from the rung 14. The hook 15 is therefore locked by the bolt 17 on the rung 14, and it thus also locks the straight position of the ladder at any set ladder length. This locking position of the bolt 17 is also additionally locked here against unintentional release, namely by the fact that the arm 26 of the bolt 17 is opposite a locking surface of the locking and latching cam 23 that is perpendicular to the plane of the image. The inclined surface 34 of the cam 23, which leads obliquely downwards from this locking surface 33 in relation to Fig. 3, enables the bolt 17 to be moved by the rung 14 from the fully extended position by sliding the arm 26 upwards on this inclined surface of the cam 23 without manual assistance until it snaps into its dash-dotted locking position,

The bolt 17 can tilt against the action of the spring 32 to a limited extent relative to the hook 15 in the direction of the double arrow D. If it is tilted upwards by hand in the direction of the arrow D' against the spring force of the spring, then it is released from the locking surface 33 of the cam 23 and the bolt 17 can now be swung back into its open position by hand, provided

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at the same time, the hook 15 is moved upwards relative to the rung 14, since the arm 26 of the bolt 37 rests against the rung 14 on top in the locking position of this bolt 17 and this rung 14 also locks the bolt 17 against unintentional unlocking. There is therefore maximum security against unintentional unlocking of the bolt 17.

The function of this ladder fitting 16 shown in Fig. 3 is therefore practically the same as that of the ladder fitting according to Fig. 2, with only the structural details being designed slightly differently. In the embodiment according to Figs. 3-5, the latch 17 can be rigid in itself due to its limited tiltability on the bearing pin 20 against the force of the return spring 32.

In the embodiment according to Fig. 3-5, the free leg 52 of the hook 15 has at the bottom at 54 the hook-shaped configuration shown with one of the

Rung 14 facing recess 53, which in the locking position of the bolt 17 when attempting to remove the hook 15 from the rung 14 without manually pivoting the bolt 17 back, comes into positive engagement with the rung 14 so that the

The bolt 17 is then locked against movement into its open position by the rung 14 due to the area 54 of the hook 15, which provides security against unintentional unlocking of the bolt 17.

increased even further.
35

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The ladder fitting 16 shown in Fig. 6 can preferably be attached to the inside of a spar 13* and also has a hook 15 with a plate 19. The hook and plate can consist of an essentially flat sheet metal part 19'. A bolt 17 designed as a piece of sheet metal is mounted on the plate 19 in a straight manner, which has an angled handle 36 at its rear end, as is known from sliding bolts on doors. The straight guidance of this bolt 17 is effected by two head rivets 37 firmly inserted into the plate 19, which penetrate a longitudinal slot 39 of the bolt 17 with little lateral play. The bolt 17 is also pulled into its locking position by a tension spring 40 and can be moved into its open position against the force of this return spring 40.

In the position shown, the latch locks the rung 13 located in the hook opening 27 against being led out of this hook opening 27. In order to be able to remove the hook 15 from the rung 14, the latch 17 is pulled back by hand and then the upper ladder part 11' is moved upwards relative to the lower _ladder part 11. After leading out the rung 14

from the hook 17, the spring 40 pulls it back into its locking position. When this hook 17 is then placed back on a rung 14, the rung 14 presses the bolt 17 into its open position against the action of the spring 40 due to its front wedge and g ₅ inclined surface 44 and, as soon as the rung 14

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then releases the bolt 17 again, it is pulled by the spring 40 into the locking position shown, in which it grips under the rung 14 and thus locks against being led out of the hook opening 27.

Such a fitting 16 can also be attached to the other spar of the ladder part 11', preferably also on the inside of the spar 13', or a hook without a latch.

The inside of a stile is the side that faces the other stile of the same ladder section. The outside of a stile is the side that faces away from the other stile of this ladder section.

Numerous modifications are possible. For example, it is possible to mount the bolt 17, regardless of whether it is a rotary or sliding bolt, not on the plate 19, but directly on the beam 11' or on a separate plate or the like assigned only to it, so that the bolt 17 and hook 15 are then not arranged on a common fitting, but can be arranged separately on the beam, either on the same or on different sides of the beam. The measures of the embodiment according to Fig. 6, according to which the sliding bolt 17 can be moved into its locked position by spring means 40 and into its open position by its inclined surface 44 through the respective rung 14, can also be provided accordingly for pivotally mounted bolts.

Claims (14)

• ■ · 5722-1 - 1 - tnsprüche 1. Extension ladder, which has at least two ladder parts that can be moved relative to one another in the longitudinal direction of the ladder, wherein the upper ladder part of two adjacent ladder parts has hooks at its lower end area for attachment to at least one rung of the lower ladder part, thereby 15 characterized in that at least a hook (15) of the relevant ladder section (11·> eir when the hook (15) is placed on a rung (14) of the relevant lower ladder section (11) automatically into a removal of the hook-20 kens (15) is assigned to the locking position of the rung (14) and is assigned to a bolt (17) which can be transferred. 5722 - 2 - 5 2. Extension ladder according to claim J, characterized in that the bolt (171) is secured in its locking position against unintentional opening _# preferably by a lock (23) blocking its movement into the open position or ■ 10 by a locking or friction position (23), i 3. Extension ladder according to claim 1 or 2, characterized in that the bolt (171 in its * Place the hook (15) on a rung (14) 15 enabling open position against automatic movement into its locking position by a locking i: or friction hold (23) is secured. i 4. Extension ladder according to claim 3, characterized in I 20 shows that the open position of the bolt \ is secured by a locking cam (23). I 5. Extension ladder according to one of the preceding I claims, characterized in that the latch f 25 when attaching the hook (15) to a rung (14) ■ the lower part of the ladder through this rung is movable from its open position towards its locked position, preferably into the locked position. 30 35 - 3 - 6. Extension ladder according to one of the preceding claims, characterized in that the bolt (17) is tiltable to a limited extent transversely to its main direction of movement and is spring-loaded. 7. Extension ladder according to claim 5 or 6, characterized in that the bolt (17) in its open position partially overlaps the opening of the hook (15) and can thereby be moved through this rung into its locking position when the hook is placed on the relevant rung (141) of the lower ladder part. 8. Extension ladder according to one of the preceding claims, characterized in that the latch (17) is rotatably mounted. 9. Sliding ladder according to claim 8, characterized in that the latch (17) is angularly designed. 10. Extension ladder according to claim 9, characterized in that one leg of the bolt forms a handle for manually moving the bolt and the other leg serves for locking. - 4 - 11. Extension ladder according to one of claims 1 - 7, characterized in that the latch (17) is a sliding bolt is. 12. Extension ladder according to one of the preceding claims, characterized in that the bolt (17) is returned to its Locking position is movable. 13. Extension ladder according to one of the preceding claims, characterized in that the latch has an inclined surface (44) which, when opened, bringing the hook (15) onto a rung (14) can be contacted by this rung so that the rung can move the latch into its open position. 14. Extension ladder according to one of the preceding claims, characterized in that the hook (15) and the associated latch (17) are parts of a ladder fitting (16) forming a structural unit.