EP0609523A1 - Hinge for step-ladder - Google Patents

Abstract

The invention relates to a connection articulation (4) of a stepladder (1), in the case of which a smaller round profile (9) is received rotatably in a larger round profile (10). In order further to develop said connection articulation such that a maintenance-free, smooth-running articulation which is insusceptible to soiling is provided, a large radial play (23) is intentionally selected between the interengaging round profiles (9, 10) of the articulation, and, in the interspace between the two round profiles, at least in the region of the mutually opposite end sides of said articulation, in each case one bearing bush (14) is provided on the smaller of the round profiles (9) in a rotationally secure manner. Said bearing bush (14), which is produced preferably from plastic, then takes on the bearing task between the smaller and the larger round profiles and avoids damage to the bearing surfaces in the region of the articulation. <IMAGE>

Description

The invention relates to a joint for a stepladder, which consists of two spar parts which are connected to one another in the region of their connection point via a conductor joint. The spar parts are usually made of an aluminum profile and it is known to form the ladder joint in such a way that a round-profiled aluminum part is formed on one spar part, which forms a central bore and has a lateral, axial slot which forms the wall of the approximately sleeve-like Profile part breaks through.

In this central bore of this sleeve-like profile part engages another sleeve part, which is connected to the opposite spar part. This engaging sleeve part is essentially of the same design as the aforementioned round-profiled sleeve part, the aforementioned larger sleeve part engaging over the smaller sleeve part and the two parts being rotatably supported one inside the other.

The known conductor joint is therefore a conductor joint consisting of two interlocking aluminum profiles, which has the disadvantage that there is direct frictional contact between the aluminum parts. If the ladder is used for a longer period of time, dirt can penetrate this joint, which leads to stiffness and creeping abrasion, which can even lead to the joint seizing. The user, who acts on the spar parts due to the relatively large lever arm and spreads the ladder, does not notice a stiff ladder joint, so that he forces the spar parts tearing apart and this can even lead to the conductor joint being torn off.

The invention is therefore based on the object of developing the articulation of a stepladder in such a way that a maintenance-free, contamination-insensitive and smooth-running joint is created.

To achieve the object, the invention is characterized by the technical teaching of claim 1.

A feature of the invention is that, starting from the known joint, in which a smaller round profile is rotatably received in a larger round profile, the play between the two round profiles is chosen to be larger and that in the space between the two round profiles at least over a certain axial length of the joint, a bearing bush is arranged between the two round profiles. It is preferred here if the bearing bush consists of a plastic material. But it can also consist of other materials, such as. B. sintered metal, ceramics and the like. More.

It is therefore important in the invention that a large radial clearance is now deliberately chosen between the interlocking round profiles of the joint and that at least in the area of the opposite end faces of this joint a bearing bush is arranged in the space between the two round profiles.

The bearing bush can extend over any axial length into the joint, ie it can also extend continuously into the entire joint.

It is preferred here if the bearing bush essentially has the appearance of a screw, namely a head with a bearing bush integrally formed thereon, which takes over the previously mentioned bearing task, it being possible for this bearing bush with a screw to be molded onto the bearing bush secure in the joint.

The screw is preferably self-tapping and engages in the central bore of the smaller round profile.

It is essential here that the bearing bush is secured against rotation on the smaller round profile. Here, the bearing bush has a slot axially breaking through the wall of the bearing bush, which extends over a leg, which leg is integrally connected to the round profile.

To further prevent rotation, a wedge rib is formed radially opposite the slot in the bearing bush and engages radially inward on the inside of the bearing bush in the associated slot of the round profile.

In this way, the bearing bush is doubly secured against rotation on the smaller round profile.

Moreover, the bearing bushing according to the invention also ensures that the joint is axially limited in terms of play.

The bearing bush serves to limit the play against axial play of the axially displaceable and interlocking round profiles. Here it is essential that the bearing bush lies flush with an inner collar on the end face of the smaller round profile and has a recessed outer collar which has a certain play to the end face of the larger round profile.

In this way, the two round profiles are axially displaceable relative to one another by the play provided by the dimension of the bearing bush.

By deliberately leaving a large radial play between the interlocking round profiles of the joint, it can no longer occur that when dirt enters this relatively large space, there is a space that damages the bearing surfaces in the area of the joint because the bearing task is now taken over by the bearing bush. So there is no longer direct contact between light metal surfaces rubbing each other, but the bearing bush itself, which is preferably made of a plastic material, takes over the bearing task between the smaller and the larger round profile.

So there is only friction between plastic material and metal surfaces, which practically creates a maintenance-free bearing that is secured against contamination.

Such a conductor joint can be pivoted through an angle of approximately 45 °. Of course, it is also possible to provide other pivoting angles or to use this ladder joint in general for pivoting components which are connected to one another in an articulated manner.

As already mentioned at the beginning, the bearing bush can extend over the entire width of the joint, but it can also be provided only on the end face, and only extend into the conductor joint by a length of about 25 mm, in order to take over the bearing task.

It is essential, moreover, that with the aforementioned screw, with which the bearing bush is held on the smaller round profile, the spar parts as a whole are secured against axial displacement, because an outer head is preferably integrally formed on the bearing bush, which is the stop for forms the displacement of the two spar parts to each other.

In this way, the entire conductor is secured against axial displacement with one screw in the bearing bush.

Moreover, it is also advantageous if the two spar parts form a tread plate in the vicinity of the joint, which tread plate is covered on the side edges in each case by a plastic cover. This plastic cover preferably also extends over the bearing bush and forms a lip in the region of the bearing bush.

The lip covers the gap between the interlocking spar parts in the area of the step plate, in the area of the cover.

The subject matter of the present invention results not only from the subject matter of the individual patent claims, but also from the combination of the individual patent claims with one another. All in the records, including the summary, disclosed information and features, in particular the spatial design shown in the drawings, are claimed as essential to the invention insofar as they are new to the prior art, individually or in combination.

The invention is explained in more detail below with the aid of drawings which illustrate only one embodiment. Here, from the drawings and their description, further features and advantages of the invention that are essential to the invention emerge.

Figur 1:

eine Stehleiter in Seitenansicht;

Figur 2:

Schnitt durch das Gelenk der Stehleiter;

Figur 3:

Draufsicht mit teilweisem Schnitt auf das Gelenk der Stehleiter;

Figur 4:

Schnitt durch das Gelenk der Stehleiter;

Figur 5:

Seitenansicht der Lagerbuchse;

Figur 6:

Stirnansicht der Lagerbuchse in Richtung des Pfeiles VI in Figur 5;

Die Stehleiter 1 nach Figur 1 besteht aus zwei über ein Verbindungsgelenk 4 schwenkbar miteinander verbundene Holmteile 2,3. Die beiden Holmteile 2,3 bilden jeweils in ihrem oberen Bereich eine Trittplatte 5 aus. In an sich bekannter Weise weist jedes Holmteil 2,3 Stufen 6 auf, die auch als Sprossen ausgebildet sein können.Show it:

Figure 1:

a stepladder in side view;

Figure 2:

Section through the joint of the stepladder;

Figure 3:

Top view with partial section of the stepladder joint;

Figure 4:

Section through the joint of the stepladder;

Figure 5:

Side view of the bearing bush;

Figure 6:

Front view of the bearing bush in the direction of arrow VI in Figure 5;

The step ladder 1 according to FIG. 1 consists of two spar parts 2, 3 which are pivotally connected to one another via a connecting joint 4. The two spar parts 2, 3 each form a tread plate 5 in their upper region. In a manner known per se, each spar part has 2.3 steps 6 on, which can also be designed as rungs.

According to FIG. 2, the two spar parts 2, 3 each form an upper tread plate 5, which are also covered laterally according to FIG. 3 by a cover 8 made of plastic.

The cover 8 extends both over the side edges of the tread plate and extends approximately over a range of 30 mm over the tread plate in the horizontal direction (see FIG. 4).

To reinforce the step plate, obliquely projecting legs 7 are formed on the underside thereof. At the same time, the tread plate 5 is connected to the spar parts 2, 3 via rivets which reach through a bore 18 (FIG. 4).

The connecting joint 4 is formed by two interlocking and rotatable round profiles 9, 10.

The smaller round profile 9 is formed integrally with the tread plate 5 via a leg 26 projecting obliquely downward from the tread plate 5. It has a slot 12 which extends through the wall and extends over the entire axial length of the round profile 9.

In the same way, the larger round profile 10 is formed on the opposing tread plate 5 and engages around the smaller round profile and also has a slot 11 which extends through the entire axial length.

It is now important that the radial play between the Smaller round profile 9 and the round profile 10 overlapping the round profile 9 is chosen so large that a bearing bush 14 can be inserted into this intermediate space.

The bearing bush 14 consists essentially of a head 13 and the bushing part 17, the bushing part of the bearing bushing 14 preferably being connected to the head 13 in one piece.

This head 13 is not absolutely necessary for the solution, because it is sufficient for the fulfillment of the bearing task to use only the bushing part 17 in order to possibly extend this over the entire axial length of the joint from one end face to the other end face.

The axial securing against displacement between the two interlocking round profiles 9, 10 can then be realized for this case with a washer, which is also secured with a screw on the end face of the smaller round profile 9.

To secure the bearing bush on the smaller round profile 9, a screw 16 is provided, which is preferably self-tapping, and which extends through a bore in the head 13 of the bearing bush 14 and is screwed into the central bore 15 of the round profile 9.

To prevent rotation of the bushing part 17 of the bearing bush 14, this is provided according to FIGS. 5 and 6 with a slot 19 which passes through the bushing part 17 over the entire axial length and which slot is penetrated by the leg 26, which is part of the round profile 9.

To improve the anti-rotation protection, a radially inward wedge rib 20 is formed on the socket part 17 opposite the slot, which wedge rib 20 engages in the slot 12 of the round profile 9.

The V-rib 20 is therefore wedge-shaped because the seat of the V-rib 20 solidifies in the slot 12 when a torque is applied.

To limit the axial stop, the head 13 of the bearing bush 14 has two collars 21, 24.

On the inner, projecting collar 21, the end face of the round profile 9 is practically free of play, while an outer collar 24 springs back behind the inner collar 21, thereby forming a structurally predetermined play 23 between the end face 22 of the round profile 10 and the associated collar 24 .

For this game 23, the two round profiles 9, 10 are then axially displaceable.

It is important, moreover, that the leg 26, which is connected to the round profile 9, forms a space 25 with respect to the underside of the tread plate 5, which is relatively large. This space can be used to hold dirt, but the connection joint between the two joint parts is covered by a cover 8, the cover standing on the round profile 10 with a lip and on the opposite, larger and rotating under this lip round profile 10 supports, while the tread plate, which is connected to the smaller round profile, has a cover which with a Lip sits firmly on this profile part.

DRAWING LEGEND

1

Stepladder

2nd

Spar part

3rd

Spar part

4th

Connecting joint

5

Step plate

6

step

7

leg

8th

cover

9

Round profile (small)

10th

Round profile (large)

11

Slot (round profile 10)

12th

Slot (round profile 9)

13

head

14

Bearing bush

15

drilling

16

screw

17th

Socket part

18th

drilling

19th

slot

20th

V-rib

21

inner waistband

22

Face

23

game

24th

outer waistband

25th

room

26

leg

27

lip

28

Space

Claims (8)

Hinge for a stepladder and the like, in which a small, tubular round profile, which is connected to a spar part, is rotatably mounted in a larger, tubular round profile, which is connected to a second spar part, each of the round profiles penetrating and penetrating the wall Has slot extending over the axial length of the profiles, characterized in that a radial play (23) is provided between the interlocking round profiles (9, 10); and that a bearing bush (14) is arranged in the space (28) between the two round profiles (9, 10) at least partially over the axial length of the joint (4). Joint according to claim 1, characterized in that the bearing bush (14) has a slot axially breaking through the wall of the bearing bush (14) which extends over a leg (26) which is connected to the round profile (9) and the bearing bush (14 ) secures against twisting. Joint according to claim 1 or 2, characterized in that a wedge rib (20) is formed radially opposite the slot (19) in the bearing bush (14) and on the inside of the bearing bush (14) is directed radially inward into the slot (12). of the round profile (9) engages. Joint according to claims 1-3, characterized in that the bearing bush (14) by means of a screw (16) which in a central bore (15) of the small round profile (9) engages, is fixed in the axial direction. Joint according to claim 4, characterized in that the bearing bush (14) has an inner collar (21) and an outer collar (24) at least at one end in the radial direction, the inner round profile (9) on the collar (21) abuts and the outer diameter of the outer collar (24) is larger than the inner diameter of the larger round profile (10) and the outer collar (24) is offset in the axial direction with respect to the inner collar (21) so that this is a game to the front of the larger round profile (10). Joint according to claims 1-5, characterized in that the bearing bush (14) consists of plastic. Joint according to claims 1-6, characterized in that at least the end face of one of the spar parts (2, 3) is designed as a tread plate (5) in the region of the joint (4). Joint according to claim 7, characterized in that the tread plate (5) is covered at least on the side edges by means of a plastic cover (8), the plastic cover (8) in the form of a lip (27) at least partially protruding over the round profile (10) .

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