DE8704486U1 - Sliding device on telescopic supports of lifting systems - Google Patents

Description

The innovation relates to a sliding device on telescopic supports with a box profile of lifting systems, in particular of aerial work platforms, consisting of plastic sliders on the first support and a coated counter surface on the second support.

In the case of telescopic beams with a box-shaped cross-section profile of aerial work platforms, rollers were initially used to carry out the linear relative movement of the individual beams to one another, with the inner beam supported on the outer beam. The telescoping process required little effort.

The idea was then to replace the rollers, which were susceptible to bearing wear and tear, with plastic gliders, which are arranged on one support and interact with sliding surfaces on the other support.

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The surfaces of the plastic gliders and the respective support that slide over one another must, however, be lubricated so that a low coefficient of friction is achieved between the plastic and the counter surface of the second support, which is usually painted. If lubrication is omitted or neglected, the coefficient of friction increases considerably, which means that the amount of force required for the telescoping process increases considerably.

The innovation is therefore based on the task of improving a sliding device of the type mentioned above by making lubrication unnecessary and still achieving a low coefficient of friction between the plastic sliders and corresponding counter surfaces.

This task is solved in a sliding device of this type according to the innovation by integrating particles of polytetrafluoroethylene (PTFE) into the plastic of the slider.

P and the mating surfaces with a sliding |

layer made of PTFE |

or PTFE. f

It is generally known that PTFE |

a very low coefficient of friction I

and an adhesion-preventing surface &iacgr; , which provides excellent sliding properties

are given. Nevertheless, so far '

Support systems for aerial work platforms these |

Properties of PTFE are not used because ] for this special purpose at the high loading

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Unfortunately, the plastic gliders did not offer the possibility of replacing them with PTFE-coated elements. However, the incorporation of PTFE chips into the pressure-resistant plastic material of the gliders has resulted _in a sufficient PTFE density on the supporting glider surface, at least after the running-in process, in order to ensure the desired favorable sliding properties. The plastic gliders are preferably made of a pourable plastic into which the PTFE chips are added during the pouring process. As many PTFE chips are added to the liquid plastic as it is able to securely bind without losing the required load-bearing capacity.

The counter surfaces for the PTFE-enriched sliding elements can have a lacquer coating that is prepared with liquid PTFE. The liquid PTFE is applied to the lacquer layer and left to dry for 12-24 hours, depending on the temperature. However, with such a preparation of the sliding surfaces there is a risk that the PTFE coating of the lacquer will be removed by certain influences. For example, the PTFE sliding layer can be removed when the device in question is washed using a high-pressure cleaner. The preferred version according to the innovation is therefore to incorporate the PTFE into the paint or lacquer that is applied to the sliding layer. For this purpose, PTFE powder with a grain size of around 2 Jim is preferably used, which is mixed with a fine powder before application.

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mixed into the primer paint or varnish.

The synthetic gliders and gliding surfaces prepared in this way run from the new

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Part of the color or varnish layer of the sliding layers rubs off. This causes the integrated PTFE to reach the surfaces in contact with each other, resulting in a particularly favorable friction coefficient behavior and, in particular, no stick-slip behavior. As the relative speed between the relevant carriers increases, the friction coefficient increases, which, when the system is controlled by the power of the medium, leads to the speed becoming lower and thus the friction coefficient decreasing again*

The innovation is briefly explained in more detail using the drawing of an example implementation.

The drawing shows a schematic cross-section through two telescopic supports of a mobile elevating work platform.

In detail, the support system consists of an outer support 1 and an inner support 2, which are essentially square or rectangular in cross-section and thus have a box profile.

The inner support 2 is supported in the outer support 1 by several plastic sliders 3, which consist of a castable, pressure-resistant plastic,

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in which a large number of PTFE particles 4 are incorporated. The particles 4 are preferably of chip size.

The inner carrier 2 has counter surfaces 5 at least over the length of the stroke, over which it is supported on the contact surfaces of the plastic sliders 3. The sliding surfaces 5 are each equipped with a fine sliding layer 6 which consists of a varnish in which PTFE powder is embedded.

1st. This can be unsintered or preferably sintered PTFE powder, which is added to the base paint or varnish with which the carrier is coated before application.

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Claims (3)

Protection claims: 1. Sliding device on telescopic supports with a box profile of lifting systems, in particular of aerial work platforms, consisting of plastic sliders on the first support and a coated counter surface on the second support, characterized, that particles (4) made of poly.etrafluoroethylene (PTFE) are incorporated into the plastic of the slider (3) and the counter surfaces (5) are provided with a sliding layer (6) which consists of PTFE or contains PTFE. 2. Sliding device according to claim 1, characterized in that the sliding layer (6) consists of a paint and/or a varnish, wherein the PTFE is incorporated into the paint or varnish. 3. Sliding device according to claim 2, characterized in that the PTFE in the form of a powder with a grain size of about 2 pm is incorporated into the paint or varnish forming the sliding layer (6).