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Title:
IMPROVED SUPPORT FOR THE END PINS OF SHAFTS
Document Type and Number:
WIPO Patent Application WO/2015/036832
Kind Code:
A1
Abstract:
The invention is a support (1) for the end pin (A1) of a shaft (A), comprising: a tube (2) suited to be associated with a supporting structure (S); a primary shaft (3) coaxially coupled inside the tube (2) and suited to be associated with power means suited to set it rotating; a prismatic seat (5) created in the end (4) of the primary shaft (3) and configured in such a way as to accommodate the end pin (A1) of the shaft (A); a sliding flange (6) associated with a shaped cap (7); moving means (8) suited to move the flange (6) between a first position (B) spaced from the tube (2) with the shaped cap (7) superimposed to the prismatic seat (5) and a second position (C) against the tube (2). Locking means (10) are provided to constrain the flange (6) to the projecting end (4) of the primary shaft (3) in the first position (B), as well as two manoeuvring rods (20, 21), each one of which cooperates with the locking means (10) when it is activated by an operator.

Inventors:
LOVATO, Ferdinando (S.S. Pasubio, 115, Costabissara, I-36030, IT)
Application Number:
IB2014/001774
Publication Date:
March 19, 2015
Filing Date:
September 09, 2014
Export Citation:
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Assignee:
SVECOM - P.E. S.R.L. (Via Della Tecnica 4, Montecchio Maggiore, I-36075, IT)
International Classes:
B65H16/06; B65H18/02; F16D1/108; F16D11/14
Foreign References:
EP0709327A11996-05-01
DE20120880U12002-03-07
GB2337249A1999-11-17
EP1182158A12002-02-27
EP0709327A11996-05-01
GB2337249A1999-11-17
DE20120880U12002-03-07
EP1182158A12002-02-27
Attorney, Agent or Firm:
BONINI, Ercole (Studio Bonini Srl, Corso Fogazzaro 8, Vicenza, I-36100, IT)
Download PDF:
Claims:
CLAIMS

1 ) Support (1 ) for the end pin (A1 ) of a shaft (A), comprising:

- a tube (2) suited to be associated with a supporting structure (S);

- a primary shaft (3) defining a main longitudinal axis (X), coaxially coupled inside said tube (2) and suited to be associated with power means suited to set it rotating according to said main longitudinal axis (X);

- a prismatic seat (5) with open profile created in the end (4) of said primary shaft (3) projecting from said tube (2) and configured in such a way that it houses said end pin (A1 ) of said shaft (A);

- a flange (6) slidingly coupled with said tube (2) and with said projecting end (4) of said primary shaft (3) and associated with a shaped cap (7);

- moving means (8) suited to move said flange (6) with respect to said tube (2) and to said projecting end (4) of said primary shaft (3) between:

- a first position (B), in which said flange (6) is axially spaced from said tube (2) according to said main longitudinal axis (X) and said shaped cap (7) is superimposed to said prismatic seat (5)

and

- a second position (C), in which said flange (6) is positioned against said tube (2) and said shaped cap (7) is arranged at the side of said prismatic seat (5);

- locking means (10) belonging to said flange (6) and to said projecting end (4) of said primary shaft (3), configured in such a way as to constrain said flange (6) to said projecting end (4) of said primary shaft (3) in said first position (B),

characterized in that it comprises:

- two manoeuvring rods (20, 21 ) slidingly housed in corresponding guide channels (22, 23) made in said flange (6), each one of said manoeuvring rods (20, 21 ) being provided with a first end (20a, 21 a) configured so as to cooperate with said locking means (10) and a second end (20b, 21 b) projecting from said flange (6) and at the disposal of the operator for moving said manoeuvring rod (20, 21 ) along the corresponding guide channel (22, 23).

2) Support (1 ) according to claim 1 ), characterized in that said locking means comprise:

- a peg (1 1 ) provided with a head (1 1 a) and slidingly coupled into a seat (12) created in said flange (6);

- a slit (13) made in said peg (1 1 ) and configured so as to house said first ends (20a, 21 a) of said manoeuvring rods (20, 21 ) slidingly coupled into said guide channels (22, 23);

- a housing (14) obtained in said projecting end (4) of said primary shaft (3) and configured so as to house said head (1 1 a) of said peg (1 1 ) that projects from said seat (12) when said flange (6) is arranged in said first position (B);

- elastic means (15) interposed between the bottom (12b) of said seat (12) and said peg (1 1 ).

3) Support (1 ) according to claim 2), characterized in that said seat (12) and said peg (1 1 ) are both cylindrical and said housing (14) and said head (1 1 a) of said peg (1 1 ) have both mutually matching profiles.

4) Support (1 ) according to claim 3), characterized in that said mutually matching profiles of said housing (14) and of said head (1 1 a) of said peg (1 1 ) are spherical profiles.

5) Support (1 ) according to any of the claims from 2) to 4), characterized in that said seat (12) with the respective peg (1 1 ) define a first longitudinal axis (Y) orthogonal to said main longitudinal axis (X) of said primary shaft (3) and each one of said guide channels (22, 23) with the respective manoeuvring rod (20, 21 ) defines a second longitudinal axis (Z1 , Z2), said first longitudinal axis (Y) and said second longitudinal axes (Z1 , Z2) being coplanar with one another.

6) Support (1 ) according to claim 5), characterized in that said second longitudinal axes (Z1 , Z2) are inclined and arranged symmetrically and on opposite sides with respect to said first longitudinal axis (Y).

7) Support (1 ) according to claim 6), characterized in that said first longitudinal axis (Y) and said second longitudinal axes (Z1 , Z2) intersect each other at the level of said peg (1 1 ).

8) Support (1 ) according to claim 7), characterized in that said second longitudinal axes (Z1 , Z2) form an angle (a) whose amplitude is 90°.

9) Support (1 ) according to any of the preceding claims, characterized in that said moving means (8) suited to move said flange (6) with respect to said tube (2) and to said projecting end (4) of said primary shaft (3) comprise a cam (30) present in said flange (6) and a counter-cam (31 ) present in said tube (2), said cam (30) and said counter-cam (31 ) being configured so as to generate a mutual rolling contact.

10) Support (1 ) according to claim 9), characterized in that said cam (30) comprises a shaped recess (32) created in said flange (6) and said counter-cam (31 ) comprises a rolling bearing (33) belonging to said tube (2).

1 1 ) Support (1 ) according to claim 10), characterized in that said rolling bearing (33) is housed inside said shaped recess (32) of said cam (30) when said flange (6) is arranged in said second position (C) against said tube (2).

12) Support (1 ) according to any of the preceding claims, characterized in that said prismatic seat with open profile (5) comprises at least one V- shaped notch.

Description:
IMPROVED SUPPORT FOR THE END PINS OF SHAFTS.

DESCRIPTION

The present invention concerns an improved support for the end pins of shafts. The support that is the subject of the invention is suited to support the end pins of shafts of any kind, but it is particularly suited to be used in the paper industry for supporting the end pin of expanding reel carrier shafts.

As is known, the winding and unwinding of continuous paper films or films of other laminar materials with reduced thickness wound in reels are performed using as a winding and unwinding core an expanding shaft whose end pins rotate on special supports that are coupled with a fixed structure.

Each support comprises a cylindrical tube that is suited to be associated with the fixed structure of the machine. In the tube there is a primary shaft that is coaxial with it and has one end projecting from the tube itself.

The projecting end is provided with a prismatic seat with open profile, configured in such a way as to accommodate the prismatic counter-profile of the pin of the shaft on which/from which the film is wound or unwound.

The end of the primary shaft opposite its projecting end is connected to power means that set the primary shaft rotating around its longitudinal axis that coincides with the longitudinal axis of the entire support.

A cylindrical flange is revolvingly and slidingly attached to the projecting end of the primary shaft on the outside of the tube, said flange being provided with a shaped cap that is arranged above the prismatic seat when the cylindrical flange is moved axially.

More precisely, the cylindrical flange can be moved axially and circumferentially with respect to both the tube and the projecting end of the primary shaft, from a backward position, in which it is arranged against the tube with the shaped cap axially offset with respect to the prismatic seat, to an advanced position in which it is arranged with the shaped cap superimposed to the prismatic seat.

In this way, when the cylindrical flange is arranged in the backward position the prismatic seat can be accessed, giving origin to a condition in which the support is open and the prismatic seat can accommodate the pin of the rotating shaft that is fitted therein.

Vice versa, when the flange is arranged in the forward position the prismatic seat cannot be accessed, giving origin to a condition in which the support is closed and the pin of the rotating shaft remains constrained in the prismatic seat.

In order to move the flange from the backward position to the forward position and vice versa, cam means are provided that comprise a cam integral with the flange and a counter-cam integral with the tube which cooperate with each other through sliding contact.

In this way, when the flange is rotated circumferentially, the interference between the cam and the counter-cam generates an axial thrust component that forces the flange to move axially causing the support to open if it was initially closed, or to close if it was initially open.

In order to ensure that during the rotation of the shaft for the winding and/or unwinding of the reel the supports stay closed and that the pins of the rotating shaft remain firmly constrained to the supports, the projecting end of the primary shaft is provided with a counteracting element that when the flange is arranged in the forward position in order to close the support is elastically snap-fitted into a special housing created in the flange itself.

Vice versa, the releasing operation is performed by manually pressing a manoeuvring button that projects from the flange and acts on the counteracting element causing it to move back in its housing so as to allow the backward movement of the flange when it is necessary to open the support.

All the supports of the type described above solve the problem of supporting the ends of the shafts during rotation, but however pose also some acknowledged drawbacks and limitations.

A first recognised drawback is constituted by the fact that the supports described above, even though they are made in such a way that they are ready to accommodate two counteracting elements and two corresponding manoeuvring buttons diametrically opposite each other in order to ensure that the opening operation is rapid and easy, each support is provided with a single counteracting element and a corresponding manoeuvring button.

In fact, the counteracting element and the corresponding button are mounted on the support in such a way that when the support is applied to the machine in operating position the button is arranged in front of the operator and therefore is easy to reach and to press.

Obviously, this would not be possible if both the counteracting elements were mounted on each support, as in order to open the support the operator would have to act on both of the manoeuvring buttons and thus also on the button arranged at the back of the support with respect to the position of the operator. This would force the operator to perform a manoeuvre for which he would need to use both hands, and which would be uncomfortable and even dangerous. For this purpose, the supports are provided with a single counteracting element with the respective manoeuvring button and thus come in a right and a left configuration, so that when the operator needs to open them he/she always works in front of them.

It is clear that this circumstance constitutes a limitation for the manufacturer, who is forced to manage two different types of supports and customise each of them during the assembly stage.

Furthermore, this distinction also involves more difficult maintenance, as the right supports are not interchangeable with the left ones and this forces the user to keep both types of supports in stock.

Another recognised drawback is due to the fact that both the counteracting element and the respective housing have a rounded prismatic shape at the ends and their coupling configuration substantially resembles the coupling configuration of a key or a tab into its seat.

As is known, the profiles in this shape are difficult to be coupled with each other and it frequently happens that at the end of the support closing operation the elastic counteracting elements do not fit perfectly and spontaneously into their respective housings.

In this case, the operator needs to move the flange manually to the completely closed position.

There is thus the risk that, if the closing operation is not completed or the user does not realise that the supports are not completely closed, starting the machine in these conditions would cause the shaft to fall down.

Another and yet not the least drawback lies in that the cam and the counter- cam mutually cooperate by sliding contact and are therefore subject to wear, which makes it necessary to replace them frequently.

The document EP 0 709 327 is known, which proposes a solution in which the coupling between the end of the shaft and the seat in the support is released by pressing a free end 24 of the locking pin that can be seen in Figure 2.

This solution is simple and can be implemented only on the side of the free end of the pin, in fact it is not possible to modify that configuration of the pin in such a way as to allow a rapid release to be obtained by acting on both sides. The document GB 2 337 249 is also known, which does not propose any manual releasing means suited to release the coupling between the seat in the support and the end of the shaft.

The document DE 201 20 880 is also known, which suggests an alternative solution, according to which a flange-shaped rotating element is used to engage and disengage the shaft end.

Finally, the document EP 1 182 158 is also known, in which there is no axial coupling, and consequently this solution does not propose any releasing means.

The present invention intends to overcome all the drawbacks that are described above and that can be observed in the rotating supports of the known type.

In particular, it is the first object of the invention to provide a support for rotating shafts made in a single type that can be opened frontally by the operator, independently of whether it supports the right pin or the left pin of the rotating shaft.

It is another object of the invention to provide a support that can be closed in a more reliable way than allowed by the equivalent supports belonging to the known art.

It is another, yet not the least object of the invention to provide a support that is less subject to wear than the equivalent supports of the known art.

The objects listed above are achieved by the support that is the subject of the invention, made according to the main claim to which reference is made.

Other characteristics of the support that is the subject of the invention are described in the dependent claims.

Advantageously, the support of the invention allows better standardisation of production compared to the supports of the known art.

Still advantageously, the support of the invention is more reliable than the supports of the known art, above all in terms of safe closure.

Finally, to advantage, the support that is the subject of the invention, being less subject to wear, requires less maintenance than the equivalent supports of the known art.

The objects and advantages described above will be illustrated in greater detail in the description of a preferred but not exclusive embodiment of the support of the invention that is provided here below by way of non-limiting example with reference to the attached drawings, wherein:

- Figures from 1 to 3 show three different axonometric views of the support of the invention arranged in the open position and of the shaft end that it supports;

- Figures from 4 to 6 show three different axonometric views of the support of the invention arranged in the closed position;

- Figure 7 shows the cross section of Figure 3 according to a section plane passing through the longitudinal axis of the support;

- Figure 8 shows a front view of Figure 7;

- Figure 9 shows the cross section of Figure 6 according to a section plane passing through the longitudinal axis of the support;

- Figure 10 shows a side view of Figure 9;

- Figure 10a shows a detail of Figure 10;

- Figure 1 1 shows an axonometric view of part of the support of the invention;

- Figure 1 1 a shows a detail of Figure 1 1 ;

- Figure 12 shows an axonometric view of a detail of the support of the invention;

- Figure 13 shows a side view of Figure 12;

- Figure 14 shows the plan view of the support of the invention partially sectioned and in the open position;

- Figure 15 shows the support of Figure 14 during the closing operation.

The support that is the subject of the invention can be seen in its entirety in the axonometric views from 1 to 6, where it is indicated as a whole by 1.

It can be observed that it comprises a tube 2 suited to be associated with a supporting structure indicated by S in Figures 7 and 9 and a primary shaft 3 defining a main longitudinal axis X, coaxially coupled inside the tube 2 and suited to be associated with power means, not represented in the figures, suited to set it rotating according to said main longitudinal axis X.

Said main longitudinal axis X defines also the longitudinal axis of the entire support 1.

The primary shaft 3 has an end 4 projecting from the tube 2 and provided with a prismatic seat 5 with open profile created therein and configured in such a way as to accommodate the end pin A1 of the shaft A.

Obviously, in order to support the shaft A, two supports 1 are provided, each one of which is arranged at the level of an end pin A1 of the shaft itself.

It is also possible to observe the presence of a flange 6 which is slidingly coupled with the tube 2 and with the projecting end 4 of the primary shaft 3 and with which a shaped cap 7 is associated.

The support 1 comprises also moving means 8 suited to move the flange 6 with respect to the tube 2 between:

- a first position indicated by B and represented in any of the Figures from 4 to 6 and 9, in which the flange 6 is axially spaced from the tube 2 according to the main longitudinal axis X and the shaped cap 7 is superimposed to the prismatic seat 5,

and

- a second position indicated by C and represented in any of the Figures from 1 to 3 and 7, in which the flange 6 is arranged against the tube 2 and the shaped cap 7 is arranged at the side of the prismatic seat 5.

As is better specified and described below, the first position B represented in Figures from 4 to 6 and 9 corresponds to the condition in which the support is closed and the end pin A1 of the shaft A is stably housed in the prismatic seat 5, while the second position C represented in Figures from 1 to 3 and 7 corresponds to the condition in which the support is open and the prismatic seat 5 can house the end pin A1 of the shaft A that is fitted therein.

According to the invention, the support 1 comprises:

- locking means 10 belonging to the flange 6 and to the projecting end 4 of the primary shaft 3 and configured in such a way as to constrain the flange 6 to the projecting end 4 of the primary shaft 3 in said first position B;

- two manoeuvring rods 20, 21 slidingly housed in corresponding guide channels 22, 23 made in the flange 6, wherein each one of the manoeuvring rods 20, 21 has a first end 20a, 21a configured in such a way as to cooperate with the locking means 10 and a second end 20b, 21 b projecting from the flange 6 and at the disposal of the operator for moving the manoeuvring rod 20, 21 along the respective guide channel 22, 23.

Regarding the locking means 10, it can be observed that they comprise:

- a peg 11 provided with a head 11a and slidingly coupled inside a seat 12 created in the flange 6;

- a slit 13 made in the peg 11 and configured in such a way as to house both of the first ends 20a, 21a of the manoeuvring rods 20, 21 ; - a housing 14 obtained in the projecting end 4 of the primary shaft 3 and configured in such a way as to house the head 11a of the pin 11 that projects from the seat 12 when the flange 6 is arranged in the first position B;

- elastic means, preferably but not necessarily a spring 15, interposed between the peg 11 and the bottom 12b of the seat 12 in which the pin 11 is housed.

The peg 11 and the seat 12 housing it define a first longitudinal axis Y that coincides with the axis of symmetry of the flange 6 and is orthogonal to the main longitudinal axis X of the primary shaft 3 and thus of the support 1.

Preferably but not necessarily, the peg 11 and the corresponding seat 12 are cylindrical and the head 11a of the pin 11 and the housing 14 that accommodates it are preferably but not necessarily spherical.

In particular, it can be observed that the cylindrical seat 12 is constituted by a through hole with circular cross section made in the flange 6.

The spherical housing 14 is coaxial with the cylindrical seat 12 and with the cylindrical peg 11 according to the first longitudinal axis Y when the flange 6 is arranged in said first position B in which the spherical head 11a of the cylindrical peg 11 is accommodated in the spherical housing 14.

Preferably but not necessarily, the cylindrical peg 11 and the housing 14 have, as already explained, spherical profiles.

In another embodiment of the invention said profiles, instead of being spherical, can be in the shape of a truncated cone or another shape, provided that they match each other in order to stably constrain to each other, without any slack, the circular flange 6 and the projecting end 4 of the primary shaft 3 in said first position B.

Vice versa, as can be observed in Figure 7, when the flange 6 is arranged in the second position C against the tube 2, the spherical head 11a of the peg 11 is completely housed in the cylindrical seat 12 and slidingly acts against the surface of the projecting end 4 of the tube 2, so that the flange 6 is free to move axially.

Regarding the guide channels 22, 23 in which the manoeuvring rods 20, 21 slide, they define second longitudinal axes, respectively Z1 and Z2, which are coplanar with each other and also with the first longitudinal axis Y defined by the cylindrical peg 11 and by the respective cylindrical seat 12. Therefore, the second longitudinal axes Z1 and Z2 and the first longitudinal axis Y are coplanar with one another according to a plane β that can be observed in Figures 14 and 15 and that is parallel to the face 6b of the flange 6.

It can be also observed in Figure 10 that the guide channels 22 and 23 and the respective manoeuvring rods 20 and 21 are arranged laterally and on opposite sides with respect to the cylindrical peg 11 and the corresponding cylindrical seat 12 and that the second longitudinal axes Z1 , Z2 defined by the guide channels 22, 23 and by the manoeuvring rods 20, 21 are inclined with respect to the first longitudinal axis Y defined by the cylindrical peg 11 and by the respective cylindrical seat 12.

The second longitudinal axes Z1 and Z2 intersect each other and the first longitudinal axis Y at the level of the peg 11 and furthermore the second longitudinal axes Z1 and Z2 form an angle a that is preferably but not necessarily a right angle.

With reference to Figures 10, 10a, 1 1 and 1 1 a, the first ends 20a, 21a of the rods are provided with lowered surfaces 24, 25 that are in contact with each other at the level of the common sliding plane containing the second longitudinal axes Z1 , Z2.

It can be observed, furthermore, that the manoeuvring rods 20, 21 and the guide channels 22, 23 that house them have circular cross section and match each other precisely, in such a way as to ensure a sliding movement without any slack.

It can also be observed that the lowered surfaces 24, 25 of the first ends 20a, 21a of the rods 20, 21 have a triangular profile 26, 27 so as to define a side 28, 29 that counteracts a thrusting plane 13a created in the slit 13 present in the cylindrical peg 11.

Preferably but not necessarily, said sides and said plane are horizontal.

The width 13b of the slit 13 is equal to the thickness 20'a, 21 'a of each first end 20a, 21a of the rods, so that only one end at a time can fit in the slit 13 and interfere with the peg 11 when the respective rod is pushed along the guide channel 22, 23 by the operator who acts on its second end 20b, 21 b projecting from the flange 6.

Each second end 20b, 21 b, in particular, has a rounded cover and is housed into a recess 6a created in the flange 6. Regarding the moving means 8 that move the flange 6 with respect to the tube 2 and the projecting end 4 of the primary shaft 3, it can be observed that they comprise a cam 30 present in the flange 6 and a counter-cam 31 present in the tube 2 that are both clearly visible, in particular in Figures 1 1 , 12, 14 and 15. Regarding the cam 30, it can be noted that it comprises a shaped recess 32 made in the flange 6, while the counter-cam 31 is constituted by a rolling bearing 33 belonging to the tube 2.

In this way, a rolling contact is obtained between the cam 30 and the counter- cam 31 instead of a sliding contact like in the supports of the known art, and this means less wear and reduces the frequency of replacement of the cam 30 and the counter-cam 31 .

Furthermore, it can be observed that when the flange 6 is arranged against the tube 2 in the second position indicated by C, which can be observed also in Figure 14, the profile of the rolling bearing 33 and therefore of the counter- cam 31 is completely housed inside the shaped recess 32 and therefore inside the cam 30, even if the shaped recess and the rolling bearing remain in contact with each other.

Finally, it can be appreciated that the prismatic seat 5 with open profile made in the projecting end 4 of the primary shaft 3 is substantially V-shaped and its shape matches the corner of the substantially square profile of the end pin A1 of the shaft A.

These profiles, however, can also have different shapes, provided that these are such as to ensure that the shaft A is driven in rotation when the primary shaft 3 is set rotating.

Also in Figures from 7 to 10 it is possible to observe the presence of a drive element 40 connected to the primary shaft 3 and provided with a prismatic insert 41 configured in such a way that it can be fitted into a prismatic seat A2 made in the head of the end pin A1 of the shaft A, as can be observed in Figure 3.

The presence of the drive element 40, which according to another embodiment may also be absent, serves to guarantee even further that the shaft A is driven in rotation when the primary shaft 3 is set rotating.

In practice, when the shaft A needs to be supported and set rotating, two supports 1 of the invention are arranged in such a way that they are aligned with each other and supported by the fixed supporting structure S. Each support 1 is arranged in the open position with the cylindrical flange 6 placed against the tube 2 and then in the second position indicated by C that can be observed in Figures from 1 to 3 and in Figure 7.

In this position the shaped caps 7 are situated beside the respective prismatic seats 5, each one of which can therefore accommodate an end pin A1 of the shaft A that is inserted therein, as can be observed in Figures 1 and 2.

In order to close the supports, the operator rotates the cylindrical flange 6 manually, in such a way that the mutual interference between the cam 30 and the counter-cam 31 , starting from the configuration with open support shown in Figure 14 and passing through the intermediate position shown in Figure 15, moves the cylindrical flange 6 axially until reaching the closed configuration of the support and thus the first position indicated by B that can be observed in Figures from 4 to 6 and in Figure 9, in which each end pin A1 is constrained between the shaped cap 7 and the prismatic seat 5.

When the supports are closed, the locking means 10 intervene to constrain the cylindrical flange 6 to the projecting end 4 of the primary shaft 3.

In fact, in Figure 9 it can be observed that in this position the spring 15 pushes the cylindrical peg 11 along the first longitudinal axis Y until its spherical head 11a is inserted in the spherical housing 14 created in the projecting end 4 of the primary shaft 3 in order to prevent any possibility of axial and radial shifting of the cylindrical flange 6.

The spherical configuration of the end of the cylindrical peg 11 has been selected because in the final stage of the axial movement of the cylindrical flange 6, in order to achieve the closed position of the support the spherical head 11a spontaneously tends to fit in the spherical housing 14 following the thrusting action of the spring 15.

In fact, as soon as the two spherical profiles start to engage with each other, they spontaneously attract each other in order to complete the coupling operation.

This ensures that the cylindrical flange 6 always achieves the fixed configuration and thus the closed configuration of the support, contrary to that which happens with the supports of the known type, in fact the latter do not ensure that such closed configuration is always achieved.

Consequently, the support that is the subject of the invention eliminates the risk that, due to its imperfect closure, the end pin A1 of the shaft A can come off the prismatic seat 5 and cause the shaft A to be detached during its rotation.

In order to open the support it is sufficient for the operator to act on the second end of any of the manoeuvring rods 20 or 21 that is more easily accessible to him/her, either 20b or 21 b, and push it axially along the corresponding direction defined by the second longitudinal axes Z1 or Z2 inside the respective guide channel 22 or 23.

In this way, the side 28 or 29 of the corresponding first end 20a or 21a of the manoeuvring rod 20 or 21 counteracts the thrusting plane 13a of the cylindrical peg 11 and, overcoming the elastic force of the spring 15, lowers it and releases its spherical head 11a from the spherical housing 14.

The cylindrical flange 6 thus returns to a condition in which it is free to rotate and move axially and thus can be re-positioned against the tube 2 in the condition with open support and then again the second position indicated by C in Figures from 1 to 3 and in Figure 7, again due to the interference between the cam 30 and the counter-cam 31 that is generated when the flange 6 is rotated manually by the operator.

It is appropriate to underline that the presence of two manoeuvring rods 20, 21 , arranged symmetrically and on opposite sides with respect to the locking means 10 and configured as described above, makes it possible to obtain a single support that can be indifferently used by the operator as a right support or a left support, which on the contrary does not happen with the supports of the known art that need to be made in the right and left version.

Finally, as the counter-cam 31 is constituted by a rolling bearing 33, the contact between the cam 30 and the counter-cam 31 takes place through a rolling movement and not through a sliding movement like in the supports of the known art, and this means less friction, less wear and therefore longer life of the support and less need for maintenance operations for the replacement of the cam and of the counter-cam, with consequently reduced costs.

According to the above, it can be understood that the support that is the subject of the invention achieves all the set objects.

In the construction stage, the support of the invention can be subjected to modifications or variants that have neither been mentioned in the present description nor represented in the attached drawings.

It is understood, however, that these modifications or variants must all be considered protected by the present patent, provided that they fall with scope of the following claims.