WO2009007284A1

WO2009007284A1 - Telescopic column stand, especially for supporting lighting or sound equipment

Info

Publication number: WO2009007284A1
Application number: PCT/EP2008/058499
Authority: WO
Inventors: Paolo Speggiorin; Stefano Guidolin
Original assignee: Lino Manfrotto + Co. S.P.A.
Priority date: 2007-07-09
Filing date: 2008-07-02
Publication date: 2009-01-15
Also published as: ITPD20070233A1

Abstract

A telescopic column stand (1) comprising at least a first tubular section (2), located within a second section (3), and able to move axially with respect to the second section (3) between a retracted configuration and an extended configuration of the stand, and means for extracting (10) the first section (2) from the second section (3). The extracting means comprise a chain (10) fixed to the first section (2) and led to engage a first return member (12, 12a, 13) mounted on the second section (3), said first return member (12, 12a, 13) being associated with a drawing mechanism (14) which can be operated from an outer section (6) of the stand to draw the chain (10) and move the first section (2) with respect to said second section (3).

Description

Telescopic column stand, especially for supporting lighting or sound equipment

DESCRIPTION Technical scope This invention relates to a telescopic column stand having the characteristics stated in the precharacterising clause of the main claim. Technological background

This invention has particular but not exclusive application in the entertainment business where the need to support lighting or sound equipment on column supports which can be adjusted for height, which can easily be transported from one place to another in a collapsed configuration which is as compact as possible, and which can easily be deployed in the desired position is known. At the same time these supports must be capable of raising significant loads, of the order of some hundred kilograms, while continuing to have small dimensions, and finally they must ensure maximum safety during deployment and retraction, and undesired and uncontrolled falls of the weights which they support must be effectively prevented. Telescopic column stands comprising two or more sections axially moving one within the other, which are extended using a system of ropes and pulleys, are known in the state of the art.

Known stands however have a number of disadvantages, among which is the fact that the cable and pulley lifting system is of significantly bulky dimensions. This is brought about, among other things, by the fact that safety criteria for systems of this type require that the diameters of the pulleys (or drums) should be larger than the diameter of the cable by a predetermined multiple (twenty times in the case of return pulleys, twenty five times in the case of drive pulleys), in order to contain the flexural stress of the cable. The cable must also be wound around the pulley or drum a minimum number of times in order to prevent unacceptable movements of the cable. Unless further and complicated technical measures are provided, this will result in the possibility that the cable will overlap on the pulley or drum in a disordered way, and might become crushed. Not only this, but the winding movement of the cable on the pulley or drum involves lateral movement of the same with a possibility of wear of the cable through friction against the lateral ends. Another disadvantage of stands constructed according to the known art lies in the fact that the cables and pulleys of the lifting system are often located completely outside the sections, in a position which is not protected against accidents.

Description of the invention

The problem underlying this invention is that of providing a telescopic column stand which is structurally and functionally designed to meet the abovementioned requirements and overcome the abovementioned limitations with reference to the cited known art.

This problem is resolved by this invention through a telescopic column stand constructed in accordance with the following claims.

Brief description of the drawings

The advantages and characteristics of the invention will become clear from the following detailed description which is given with reference to the appended drawings which are provided purely by way of non-limiting example and in which :

- Figure 1 is a perspective view of a telescopic column stand obtained according to the present invention, - Figure 2 is a view of the stand in Figure 1 in longitudinal cross- section,

- Figure 3 is a view of a detail of the stand shown by III in Figure 2 on a magnified scale,

- Figure 4 is a view along the line IV-IV in Figure 2 on a magnified scale and in transverse cross-section,

- Figure 5 is a view of a component of the stand in Figure 1 on a magnified scale and in partial cross-section,

- Figures 6 and 7 are views of corresponding details of the component in Figure 5 in axial cross-section. Preferred embodiment of the invention

In the figures, 1 indicates a telescopic column stand as a whole, constructed according to this invention.

Stand 1 comprises a plurality of tubular sections each housed within the adjacent section in such a way as to allow them to slide with respect to each other along axial direction X. The number of sections is not generally a limitation : however in the preferred embodiment described here the sections are five in total and are referred to as the first, second, third, fourth and fifth section going from the innermost section to the outermost section. These sections are respectively indicated in the appended figures by numerical references from 2 to 6. The stand according to this embodiment however comprises at least two sections, so that it is possible to define an inner section and an outer section of the stand, which in this case are represented by first section 2 and fifth section 6 respectively. In the rest of the description therefore first section 2 and fifth section 6 will also be referred to respectively as the "inner section" and "outer section" of stand 1, while the second, third and fourth sections may be referred to as a whole as "intermediate sections". It goes without saying that in the case of a stand with only two sections the first and second sections will be the inner section and the outer section respectively.

At the base of outer section 6 there are hinged supporting legs, all indicated by 8, which can be moved between an extended position shown in Figure 1, which imparts the necessary stability to stand 1, and a folded position, not shown, in which legs 8 are brought up against outer section 6, which is useful for transport and storage of stand 1. Stand 1 also comprises means for extracting sections 2 to 5 respectively from sections 3 to 6 in order to permit stand 1 to pass from a retracted configuration in which each section is substantially housed within the whole of the adjacent section (configuration shown in the appended figures) and an extended configuration in which the sections are largely extracted from the adjacent sections.

Each section is also provided with lower stop blocks 7 and upper stop blocks (not shown in the figures) to restrict the travel of each section with respect to the adjacent section in which it is housed. The upper stop blocks are further positioned in such a way as to optimise the maximum extension which can be achieved by stand 1 with adequate resisting to bending of the same in relation to the load which has to be supported. The extraction means comprise a chain 10 which is engaged and conducted from a first extremity 11a attached to the base of first section 2, over the return members, all indicated by 12, mounted in intermediate sections 3 to 5, to a main return member 13 mounted on outer section 6 to which it is kinematically connected to a drawing mechanism 14 which can be driven in rotation from outside stand 1. After main return member 13 chain 10 is conducted to the base of outer member 6 and from there passes through the bases of the intermediate sections back to the base of first section 2 where it is attached at its second extremity lib. For greater safety the extraction means for stand 1 comprise a further two chains 10a and 10b, put beside the chain 10, whose circuits are wholly similar to that of chain 10. The detailed description which follows relates to chain 10 and is therefore also similarly applicable to the circuits of chains 10a and 10b.

As can better be seen in Figure 3, the first extremity of chain 10 is anchored to a plate 15 attached to the base of first section 2 in such a way as to project therefrom by an amount equal to the cross-section of chain 10. Second extremity lib is connected to the base of first section 2 by a chain-tensioning device comprising a rod 16 to one end of which second extremity l ib of the chain is attached and whose opposite extremity is adjustably anchored to first section 2 through a screw 17. A spring 18 is placed between screw 17 and the base of first section 2 to impart advantageous resilient behaviour so as to dampen out any unforeseen tensioning of chain 10.

From its first extremity 11a chain 10 extends to a first return member 12a located at the top of second section 3, forming an ascending segment 20 running within an intermediate space 19 between the first and second sections parallel to direction X. Ascending segment 20 is engaged around a toothed wheel 21 of first return member 12a from which there departs a descending segment 22 of chain 10 which extends towards the base of second section 3 within intermediate space 19. Descending segment 22 is advantageously guided in a condition of proximity to ascending segment 20 through the action of a guide pinion 23 of first return member 12a which engages descending segment 22 on the side opposite toothed wheel 21. Guide pinion 23 has the same characteristics as toothed wheel 21 and is mounted in a vertically offset position with respect to it.

It will be appreciated that the transverse dimensions of the chain within intermediate space 19 are minimised in this way. The provision of chain 10 also advantageously makes it possible to use a toothed wheel 21 of relatively reduced diameter (of indicatively between 25 and 40 mm, with a number of teeth between 8 and 12), significantly reducing the overall dimensions of return member 12a.

First return member 12a, like the other return members located at the tops of the sections, is finally enclosed in an enclosure 24 attached to the top of second section 3. As mentioned above, between first and second sections 2 and 3 there is an intermediate space 19 within which the two lengths 20, 22 of chain 10 run. Intermediate space 19 has a generically trapezoidal cross-section and is bounded by the particular cross-section of the sections, which can more particularly be seen in Figure 4: first section 2 has a cross-section which is a segment of a circle, for example with an angle of more than 180° at the centre, while second section 3 has a perimeter with a first arcuate portion of circumference 3a which follows and matches the shape of first section 2 and which is then extended by a pair of substantially straight symmetrical lines 3b and closed by a straight connecting portion 3c substantially parallel to the chord of the circular segment defining the cross-section of first section 2.

Descending segment 22 extends to the base of second section 3 where it engages a return member 12 mounted there. Return member 12 is substantially identical to, and a mirror image of, first return member 12a and therefore its components are indicated using the same reference numbers.

Descending segment 22 is then led via a guide pinion 23 to engage a toothed wheel 21 from which a further ascending segment 25 departs leaving second section 3 and rises in an intermediate space 26 which is wholly similar to intermediate space 19 and formed between second section 3 and third section 4.

The course of chain 10 then continues in a similar manner between the return members located at the top and base of the third and fourth sections 4 and 5 until it engages main return member 13 located at the top of outer section 6, from which it is led to the base of outer section 6 and from there to the base of first section 2 via two pinions 27. Main return member 13 is directly connected to drawing mechanism 14 which comprises a control shaft 30 supported on two bearings 31, at the opposite ends of which are attached a pair of handles 32 extending in radially opposite directions to allow control shaft 30 to be rotated by an operator.

Drawing mechanism 14 also comprises a gear system comprising a first gear wheel 33 integrally mounted on control shaft 30 and a second gear wheel 34 screw mounted on a drive shaft 35 of main return member 13 on which a toothed wheel 36 engaged by chain 10 (and the other toothed wheels belonging to the circuits of chains 10a and 10b) is keyed. The gear system is such as to provide a suitable reduction ratio to permit the sections to be extracted even when significant loads are present. For example, first and second gear wheels 33, 34 may have 14 and 34 teeth respectively.

Second gear wheel 34 is screw mounted onto shaft 35, so that following relative rotation between this and shaft 35 second wheel 34 is moved axially along shaft 35 towards or away from toothed wheel 36. The course of second gear wheel 34 away from toothed wheel 21 is limited by a stop 37.

Drawing means 14 also comprise friction means, indicated as a whole by 40, placed between second gear wheel 34 and the toothed wheel 36, which can pass from an engaged configuration in which second gear wheel 34 and driven shaft 35 are kinematically united and a disengaged configuration in which they are kinematically separate. From toothed wheel 36 friction means 40 comprise a friction disk 41 integrally mounted on driven shaft 35 through tongue connection means 42, on which disk are mounted friction members 43, a toothed wheel 44, which is mounted so as to idle on driven shaft 35, and a washer 45 adjacent to second gear wheel 34.

The thread providing the screw engagement between second gear wheel 34 and driven shaft 35 is such that the second gear wheel is moved axially towards friction means 40, and therefore towards toothed wheel 36, when control shaft 30 is rotated in the direction which brings about extraction of sections 2 to 5 and moves stand 1 into the extended configuration.

It follows that friction means 40 are also engaged when driven shaft 35 tends to rotate with respect to second gear wheel 34 in the opposite direction, that is in the direction in which the sections are retracted (this typically occurs when stand 1 is subjected to a load). Stand 1 is also provided with safety means to maintain stand 1 in an extended position and to prevent sections 2 to 5 yielding under the weight of the load and suddenly re-entering the sections housing them. The safety means comprise first one-way stop means including a ratchet pawl 50 which is engaged and stressed by a pair of springs 51a and 51b against toothed wheel 44 of friction means 40. The profile of the teeth of wheel 44 and the profile of 50 are such that ratchet pawl 50 prevents rotation of toothed wheel 44 in one direction only, as more particularly explained below. The safety means also comprise second one-way stop means including a stop tooth 52 integral with enclosure 24 of main return member 13, which is stressed by a spring 53 engaging a pinion 54 mounted on control shaft 30 with a tongue coupling 55. Again in this case the profile of stop wheel 52 and of the tooth of pinion 54 are such that rotation is prevented in one direction only. A lever 56 to displace tooth 52 from engagement with pinion 54 against the force of spring 53 is provided on stop tooth 52.

A further safety means is also provided by multiplying the chain circuits, which may be double or triple (as in the example described) depending upon the maximum loads which the stand has to support. Stand 1 is operated as follows. Starting from the fully retracted configuration illustrated in Figure 1, stand 1 is extended by rotating handles 32 in a predetermined direction. Any load, not shown, for example lighting equipment or sound equipment, is attached to the top of first inner section 2. Rotation of handles 32 brings about a matching rotation of control shaft 30 and first gear wheel 33, which causes second gear wheel 34 to rotate in the opposite direction. Through the screwed engagement on driven shaft 35 the latter is moved axially towards toothed wheel 36 so as to move washer 45 and toothed wheel 44 against friction disk 41, engaging friction means 40 and uniting second gear wheel 34 with driven shaft 35. Toothed wheel 36 is then caused to rotate and chain 10 (like the other chains 10a, 10b) is drawn through return members 12. Drawing of chain 10 brings about extraction of sections 2 to 5 upto the upper stop blocks. It will be noted that the rotation of control shaft 30 and driven shaft 35 in the direction described above is not obstructed by either stop tooth 52 or ratchet pawl 50. It will also be noted that when handles 32 are released friction means 40 remain engaged because the weight of the load tends to cause driven shaft 35 to rotate in such a way as to cause second gear wheel 34 to move towards toothed wheel 36. As friction means 40 are in the engaged condition, reverse rotation of driven shaft 35 is prevented by the 1-way action of ratchet pawl 50 and by the action of stop tooth 52 which engages pinion 54, enabling stand 1 to remain in the extended position even when under load. To return stand 1 to the retracted configuration, action is required on lever 56 to disengage stop tooth 52 from pinion 54 and then deliberately rotate handles 32 in the direction opposite to that used in the previous stage. In this way second gear wheel 34 is rotated with respect to driven shaft 35, away from toothed wheel 36, disengaging friction means 40, allowing toothed wheel 36 to rotate in the opposite direction and therefore sections 2 to 5 to retract within the adjacent sections. As soon as the rotation of handles 32 and therefore of second gear wheel 34 is interrupted rotary movement of driven shaft 35 driven by toothed wheel 36 tends to bring these components together, so as to again engage friction means 40 and therefore restore the one-way arresting action of ratchet pawl 50. This invention therefore overcomes the abovementioned problem with reference to the cited known art, while at the same time offering many other advantages, among which the fact that the entire circuit of the chain lies within the telescopic column stand. In addition to this, dimensions are very much smaller in comparison with a similar stand using a cable and pulley system for the same maximum loadbearing capacity.

Claims

1. A telescopic column stand (1) comprising :

- at least a first tubular section (2) located within a second section (3) and able to move axially with respect to the second section (3) between a retracted configuration and an extended configuration of the said stand, and

- means for extracting (10) said first section (2) from said second section (3), characterised in that said extracting means comprise a chain (10) fixed to said first section (2) and led to engage a first return member (12,

12a, 13) mounted on said second section (3), said first return member

(12, 12a, 13) being associated with a drawing mechanism (14) which can be operated from an outer section (6) of said stand to draw said chain (10) and move said first section (2) with respect to said second section (3).

2. Stand according to claim 1, in which said chain (10) is open and is fixed at each of the opposite ends (11a, l ib) to said first section (2).

3. Stand according to claim 2, in which each of the ends (11a, l ib) are attached to a base of said first section (2). 4. Stand according to one or more of the preceding claims, in which tensioning means (18) for tensioning said chain (10) are provided . 5. Stand according to one or more of the preceding claims, in which provision is made for more than two sections, and are therefore defined intermediate sections (3, 4, 5), between said first section (2) and said outer section (6), each intermediate section (3, 4, 5) being housed so as to move axially within an adjacent section, and the said chain (10) being led to engage successive return members (12, 12a, 13) mounted in succession on said intermediate sections (3,

4,

5) as far as a main return member (13) mounted on the said outer section (6).

6. Stand according to claim 5, in which said return members (12, 12a, 13) are respectively mounted at the top and bottom of each of the intermediate sections (3, 4, 5) as far as the said outer section (6).

7. Stand according to one or more of the preceding claims, in which said chain (10) extends from said first section (2) towards said first return member (12a) and, if appropriate, between successive return members mounted on intermediate sections (3, 4, 5) within an intermediate space (19) defined between two adjacent sections (2, 3, 4, 5, 6).

8. Stand according to claim 7, in which each of the said return members (12, 12a, 13) comprise a first toothed wheel (21) surrounded and engaged by said chain (10) defining a pair of substantially parallel segments (22, 25) in opposite directions, and a guide pinion (23) engaging one segment (22) of said chain (10) on the side opposite the said first toothed wheel (21) to guide said segment (22) in a condition of proximity to the other segment of said chain (10) within said intermediate space (19).

9. Stand according to one or more of claims 5 to 8, in which the sections as a whole (2, 3, 4, 5, 6), including said first (2) and second section (3) and said outer section (6), are at least four in number.

10. Stand according to one or more of claims 5 to 9, in which, after said main return member (13) mounted on said outer section (6), said chain (10) is led to the base of said outer section (6) and guided from there towards the base of said first section (2) passing through the bases of any intermediate sections (3, 4, 5).

11. Stand according to one or more of claims 5 to 10, in which said main return member (13) mounted on said outer section (6) is directly connected to said drawing mechanism (14).

12. Stand according to one or more of claims 5 to 11, in which said drawing mechanism (14) comprises a gear system (30, 32, 33, 34, 36) which can be driven in rotation from outside the said stand and which can transmit motion to said main return member (13).

13. Stand according to claim 12, in which tracking friction means (40) are provided between said gear system (30, 32, 33, 34) and said main return member (13) to pass in a selectable way from a configuration in which said gear system (30, 32, 33, 34) and said main return member (13) are kinematically united to a configuration in which they are kinematically separate.

14. Stand according to claim 13, in which said gear system (30, 32, 33, 34) comprises a first gear wheel (33) mounted on a control shaft (30) engaging a second gear wheel (34) screw-mounted on a driven shaft (35) of said main return member (13) on which there is mounted a toothed wheel (36) which engages said chain (10), in such a way that said second gear wheel (34) is moved axially towards or away from said toothed wheel (36) depending upon the relative rotation between said second gear wheel (34) and the said driven shaft (35) so as to engage or disengage said friction means (40) and kinematically unite or separate said second gear wheel (34) and the said toothed wheel (36).

15. Stand according to claim 14, in which the direction in which said second gear wheel (34) is screwed on the driven shaft (35) is such as to move said second gear wheel (34) axially towards said toothed wheel (36) when the said gear system (30, 32, 33, 34) is rotated in the predetermined direction to extract said first section (2).

16. Stand according to one or more of claims 13 to 15, in which first oneway stop means are provided comprising a ratchet pawl (50) loaded to engage a toothed wheel (44) of said friction means (40) mounted so as to idle on the said driven shaft (35).

17. Stand according to one or more of claims 14 to 16, in which second one-way stop means comprising a safety tooth (52) of one piece with said outer section (6) and resilien y loaded so as to engage a pinion

(54) mounted on said control shaft (30) to immobilise rotation of the latter are provided.

18. Stand according to claim 17, in which said stop tooth (52) can be selectively disengaged from the said pinion (54).

19. Stand according to one or more of claims 14 to 18, in which a pair of handles (32) are located at the opposite longitudinal extremities of said control shaft (30).