EP2759506B1

EP2759506B1 - Telescopic column

Info

Publication number: EP2759506B1
Application number: EP14150816.8A
Authority: EP
Inventors: Vittorio Lancini
Original assignee: Lanmar SpA
Current assignee: Lanmar SpA
Priority date: 2013-01-23
Filing date: 2014-01-10
Publication date: 2016-01-06
Anticipated expiration: 2034-01-10
Also published as: ITBS20130006A1; EP2759506A1

Description

Field of the invention

The present invention is generally applicable in the technical field of the lifting devices and, particularly, the object is a telescopic column.
More in detail, the present invention relates to a telescopic column of the type using ropes.

Prior art

It is known that it is necessary to lift devices, elements and people at predetermined altitude for the most diverse purposes. For example, it may be necessary to lift a technician for cable laying and maintenance, or cameras for top shots. Another application relates to the lifting of floodlights to light up areas of different widths.
Anyway, extendible systems are usually used for the lifting operation. Among such systems, the most widely used are telescopic columns comprising two or more stems and, on the top of said columns, there are the objects or the people to be lifted.
The system for lifting or lowering the telescopic column may be both of the mechanic and hydraulic types. In the first case, one or more ropes controlled by winches or the like are generally used. In the second case, air or oil hydraulic systems are generally used.
In both situations, firstly it is fundamental for the stems to have the possibility to slide easily one inside the other. So, frictions must be avoided as much as possible.
Another relevant aspect to be taken into consideration is that malfunctions may occur and provoke the swift closure of the column. In case of the hydraulic system, the system is safe, since also in case of leaks in the hydraulic circuit, the descent of the stems of the column takes place slowly while the circuit is emptying itself slowly.
On the other hand, in case of the mechanic lifting with ropes, the breaking of the ropes provokes the swift falling of the stems with swift closure of the column. It is self-evident that this situation is to be avoided, since the loads are typically relevant and this may not only damage the system, but it is also dangerous for the people present in the nearby area. It is even more evident the danger if the column is used to lift people.
To solve this problem, it is known the safety system described in the EP 1 674 791 . This system advantageously allows to block the descent of one stem inside the next stem in case of rope breaking, thanks to the automatic action of a lock lever positioning itself within corresponding slots realized on the lateral wall of the two stems which enter one inside the other.
Even though this system allows to avoid the quick sliding of a stem inside the other in case of rope breaking, it presents some drawbacks.
Firstly, it is observed that the lock system is located inside the stems and this hampers the fast and simple accessibility. As a consequence, maintenance, cleaning and surveillance of the functionality of the system are more difficult. All these aspects undermine, as it will be later explained, the safety of the system.
As said, the lever is activated as a consequence of the rope breaking. More in details, the lever is activated through the translation of a pivot pin of a pulley inside two partially overimposed slots which develop according to two mutually non-aligned and non-parallel axis. The translation movements provoke not only a rubbing of the pin on the slots which may cause their wear, but such translations may also be hindered by the presence of dirt or foreign bodies in one of said slots. Besides this, the getting dirty or the clogging, partial too, of the slots are events difficult to detect because the inspection of the system is difficult since such system is located inside the stems.
Furthermore, it is observed that the telescopic column is generally used outdoors and this favors the getting dirty or the like which may jeopardize the translation of the pin in the slots and, as a consequence, also the correct functioning of the safety lock.

Presentation of the invention

Object of the present invention is to at least partially overcome the above mentioned drawbacks, by providing a telescopic column having one locking assembly of the sliding of one stem inside the other after the breaking of ropes.
Another object is that the above mentioned locking assembly allows easy inspection and maintenance.
Another object is that the locking assembly does not present reciprocally sliding parts in order to avoid the damaging thereof because of rubbing.
Another object is that the locking assembly is easy to clean in order to avoid that dirt or foreign bodies may undermine its functionality. In any case, an additional object is that the locking assembly of the column of the invention operates correctly also in the presence of dirt and foreign bodies.
Another object of the invention is that the telescopic column presents decreased frictions between the stems in comparison with the equivalent known columns in order to facilitate lifting and closure.
These and other objects, as better explained hereafter, are fulfilled by a telescopic column according to the following claims, which are an integral part of the present description.
In particular, the telescopic column comprises at least one pair of stems slidably arranged one inside the other, at least the inside of which being provided with a plurality of slots arranged mutually aligned along the longitudinal extension axis of the same stem.
The telescopic column also comprises at least one rope connected at least to the stem immediately external to the internal stem for the handling of the latter with respect to the external stem.
Besides this, the column comprises at least one locking assembly of the sliding of the internal stem with respect to the external stem at least in the direction of penetration of the internal stem into the external one.
According to an aspect of the invention, the locking assembly comprises at least one lever that has a pivot pin placed at an intermediate point of the lever itself.
One first end of the lever is capable of entering in at least one of the slots to lock the sliding movement in the direction of penetration of the internal stem in the external one. Besides this, there be elastic means capable of pushing the first end to be inserted into the slots.
According to another aspect of the invention, the lever has one second end placed in contact with the rope so that the pressure exerted by the rope on the second end, when the rope is tightened, contrasts the action of the elastic means maintaining the first end disengaged from any slot.
Advantageously, the telescopic column of the invention has a locking assembly whose functioning depends on the oscillation of a lever pivoted at an intermediate point of it and not at one of its ends. In this way, the locking is activated by rotating the lever on its pin without the mechanical translations of pins in slots. In particular, the rest status of the locking assembly of the invention is kept by the pressure exerted by the rope on the second arm of the lever, that is, advantageously, through mechanical pressure and not through translations with rubbing frictions. This allows to save, in the long time, the functionality of the locking group of the invention.
Besides this, since the rest or work positions of the locking group of the column of the invention are obtained through the presence or the absence of pressure of the rope on the second arm of the lever, it is self-evident that, advantageously, the locking assembly is not subject to the effects caused by dirt or by insertion of foreign bodies.
This allows also to advantageously overcome the drawback concerning the difficulty in accessibility of the equivalent locking assemblies of the prior art. In the case of the invention, in fact, the inspection of the locking assembly is not necessary anymore and also cleaning and maintenance interventions can be advantageously occasional.
However, according to another aspect of the invention, the locking assembly of the column of the invention is positioned outside the external stem and this allows, advantageously, the constant inspection, the easy cleaning and, likewise, the easy maintenance.

Brief description of the drawings

Further features and advantages of the invention will appear more evident upon reading the detailed description of some preferred, non-exclusive embodiments of a telescopic column according to the invention, which are described as non limiting example with the help of the annexed drawings, in which:

FIG. 1 is an axonometric view of a telescopic column according to the invention;
FIGS. from 2 to 5 are particulars of the telescopic column of FIG. 1.

Detailed description of some examples of preferred embodiments

With reference to the cited figures, and in particular to fig. 1, it is described a telescopic column 1 suitable for the lifting of vaious loads. In the figures, in particular, a telescopic column for the lifting of illumination groups P is represented, however this shall not be considered limiting for different applications like, for example, the lifting of people.
As it can be observed from the figures, the telescopic column 1 comprises a plurality of stems 2 slidably arranged one inside the other. In particular, apart from the first stem 3, which, in the column 1, has a lower position when the column is extended, all the other stems 4 are intended to slide inside another stem 2 and are provided with, as it can be observed in the particular of fig. 2, a plurality of slots 5 arranged mutually aligned along the longitudinal extension axis X of the respective stem 4.
Obviously, such an embodiment is only a non limiting example of the invention. In fact, according to different embodiments also the first stem is provided with slots or only some of the stems are provided with slots.
In the figures it can be observed that the stems are of square section, but also this detail shall not be considered as limiting for different embodiments in which the stems have a section of a different geometric shape. In this sense, a very simple example is a telescopic column with the stems having circular section.
As previously said, the telescopic column 1 is of the rope type. In this sense, it comprises, as it can be observed in the particular of fig. 3, a plurality of ropes 6 each coupled to an internal stem 7 and with the one immediately external 8 to the internal stem. Such ropes 6 allow the lifting of the column 1 and, for the safety reasons previously cited, the column 1 comprises also a plurality of locking assemblies 10 of the sliding of the internal stems 7 with respect to the respective external stems 8 in the direction of penetration of the internal stems into the external ones in case of breaking of the corresponding ropes 6.
In particular, as it can be observed in fig. 4 and in the particular of fig. 5, each locking assembly 10 comprises a support body 10a typically connected to the external surface of the external stem 8. The locking assembly 10 comprises also a lever 11. The latter, as such, has a pivot pin 12 placed at an intermediate point of the lever 11 and bound to the support body 10a. In this sense, the lever 11 has two arms 13 and 14 corresponding to its two ends 15 and 16.
More in details, the first arm 13 is susceptible to enter one of the slots 5 to lock the sliding movement in the direction of penetration of the internal stem 7 inside the stem immediately external. The insertion movement is obtained by elastic means 18, typically constituted by a spring, susceptible to push the first arm 13 in the direction of penetration into a slot 5. In particular, the elastic means 18 have a first end 19 connected to the first arm 13 of the lever 11 and a second end 20 connected to the support body 10a. The elastic means 18, then, are pulled when the first arm 13 is far from the internal stem 7 and, so, also from the slots 5. When they are able to move freely, they tend to return to rest position while dragging the first arm 13 towards the stem 2 and to insert themselves, if possible, into a slot 5.
According to another aspect of the invention, the locking assembly 10 comprises also adjustment means 21 for the tightening of the elastic means 18 in order to regulate the action thereof. In the figures they are constituted by screw means through which the connection point of the first end 19 of the elastic means 18 is moved, but this shall not be considered as limiting for different embodiments of the invention. Likewise, the number of elastic means, of levers, the presence or the number of support bodies, the disposition of the locking assembly on the stems.
According to another aspect of the invention, the second arm 14 of the lever 11 is placed in contact with the corresponding rope 6 so that the pressure exerted by the latter, when it is tightened, contrasts the action of the elastic means 18 keeping the first arm 13 disengaged from any slot 5.
In other words, since the rope 6 typically has one first end connected to the relative internal stem 7 and one second end connected to the relative external stem 8 (which is also the one to which the locking assembly 10 is connected), for the good functioning of the telescopic column 1 it must be always tightened. Such tightening leads the rope 6 to press on the second arm 14 contrasting the effects of the elastic means 18 and keeping the first arm 13 far from the slots 5. The sliding between the stems 2 is then free.
In case of breaking of a rope 6, the internal stem 7 starts a slipping movement inside the external stem 8. At the same time, the second arm 14 is not subject any more to pressure and, so, the elastic means 18 make the lever 11 rotate around its pivot pin 12 leading the first arm 13 to insert itself into the first slot 5 encountered. This provokes the immediate stoppage of the slipping movement.
In other words, the locking assembly 10 of the invention allows the fast block of the slipping of one stem 2 inside another in case of breaking of the corresponding rope 6. Besides this, it can easily be inspected since it is placed outside the stems 2 and, as a consequence, it has an easy maintenance. However, since the action of the locking assembly 10 is due to elastic means and to the pressure of the rope 6 on the second arm 14 of the lever 11, advantageously dirt or foreign bodies are not able, in any case, to undermine the action of the locking assembly 10. So, the latter is safe and requires little maintenance. Furthermore, it does not present rubbing movements and the like, so it is not subject to wear.
In order to allow a convenient disposition of the rope 6 and also the handling of the internal stem 7 with respect to the immediately external one, the locking assembly 10 comprises also a transfer pulley 25 which represents the only part of the assembly 10 always moving, and this guarantees the almost total absence, in the locking assembly 10, of parts gradually subject to wear. The rotation center of the pulley 25 coincides with the pivot pin 12 of the lever 11.
As previously said, one of the problems of the known prior art is the easiness extraction of the internal stems 2. In particular, there may be rubbing frictions between the internal stems 2 and those immediately external ones during the extraction and the closure movements of the telescopic column 1.
For this reason, according to another aspect of the invention, the column 1 comprises a slide assembly 30 interposed between one portion of the internal stem 7 and one corresponding portion of the corresponding external stem 8 in order to facilitate the sliding of one inside the other.
More in detail, the slide assembly 30 comprises four first pulleys 31 connected to the ends of the locking assembly 10 and further four second pulleys 32 connected to the opposite end of the stem 2. The first pulleys 31 allow to facilitate the sliding between the stem 2 to which the same are connected and the immediately internal stem, the second pulleys 32 between the stem 2 to which they are connected and the immediately external one. The position of the first 31 and the second pulleys 32, that is at the ends of the stems 2, allow to keep centered each stem 2 with respect to the immediately external one, facilitating, in this way, the sliding.
It is self-evident that what has been just described is only one embodiment example of the slide assembly 30. So, this has not to be considered as limiting for different embodiments in which, for example, the stem section is not quadrangular and, consequently, the number and disposition of the pulleys change. Also the position and the number of the slide assemblies may vary, likewise, the pulleys may be replaced by different elements like, for example, bearings.
In the light of the foregoing, it is evident that the telescopic column overcomes the drawbacks of the known prior art since it is provided with a locking assembly for the sliding of one stem inside the other, after the breaking of ropes and this locking assembly has easy inspection and maintenance.
Furthermore, the locking assembly does not have reciprocally sliding parts so that the wear for rubbing is avoided and the good functioning of the locking assembly is guaranteed over time. The locking assembly is also easy to be cleaned and, in any case, dirt or foreign bodies do not undermine the functionality thereof.
The telescopic column of the invention is safe and easy to use also thanks to the slide assemblies which substantially reduce the sliding frictions between the stems with respect to the known equivalent columns.
The telescopic column of the invention is susceptible to many changes and variants, all falling within the inventive concept expressed in the annexed claims. All particulars may be replaced by other technically equivalent elements, and the materials may be different according to the needs, without departing from the scope of the invention.
Even though the telescopic column has been described with particular reference to the accompanying figures, the numerals referred to in the disclosure and claims are only used for the sake of a better intelligibility of the invention and shall not be intended to limit the claimed scope in any manner.

Claims

A telescopic column comprising:
- at least one pair of stems (2) slidably arranged one inside the other at least the inside (7) of which is provided with a plurality of slots (5) arranged mutually aligned along the longitudinal extension axis (X) of said stem (2);

- at least one rope (6) connected to at least the stem immediately external (8) to the internal stem (7) for the movement of the latter with respect to said external stem (8);

- at least one locking assembly (10) of the sliding of said internal stem (7) with respect to said external stem (8) at least in the direction of penetration of said internal stem (7) in said external stem (8),
said locking assembly (10) comprising at least one lever (11) having:
- a pivot pin (12) placed at an intermediate point of said lever (11);

- a first arm (13) capable of entering in at least one of said slots (5) to lock said sliding movement in the direction of penetration of said internal stem (7) in said external stem (8);

- elastic means (18) capable of pushing said first arm (13) to be inserted into said at least one of said slots (5);
characterised in that said telescopic column further comprises:
- a second arm (14) placed in contact with said rope (6) in such a way that the pressure exerted by said rope (6) on said second arm (14), when said rope (6) is tightened, contrasts the action of said elastic means (18) maintaining said first arm (13) disengaged from any one of said slots (5).
Telescopic column according to claim 1, wherein said locking assembly (10) comprises at least one transfer pulley (25) of said rope (6) whose rotation center coincides with said pivot pin (12) of said lever (11).
Telescopic column according to claim 1 or 2, wherein said locking assembly (10) comprises at least one support body (10a) at least for said lever (11) and said elastic means (18).
Telescopic column according to claim 3, wherein said support body (10a) is at least partially associated with the outer surface of said external stem (8).
Telescopic column according to any one of the preceding claims, wherein said elastic means (18) are constituted by a spring which a a first end (19) is connected to said first arm (13) and a second end (20) is connected to said support body (10a).
Telescopic column according to any one of the preceding claims, comprising adjustments means (21) of the tightening of said elastic means (18).
Telescopic column according to any one of the preceding claims, wherein said rope (6) has a first end connected to said internal stem (2) and a second end connected to said external stem (8).
Telescopic column according to any one of the preceding claims, comprising a slide assembly (30) interposed between at least one portion of said internal stem (7) and at least one portion of said external stem (8) to facilitate the sliding of said internal stem (7) in said external stem (8).
Telescopic column according to claim 8, wherein said slide assembly (30) comprises at least one first pulley associated with at least one end of said external stem (8) and placed in contact with the side surface of said internal stem (7).
Telescopic column according to claim 7 or 8, wherein said slide assembly (30) comprises at least one second pulley associated with at least one end of said internal stem (7) and placed in contact with the inner surface of said external stem (8).