WO2003053636A1

WO2003053636A1 - Clamp, particularly for supporting optical and photographic/cinematographic equipment

Info

Publication number: WO2003053636A1
Application number: PCT/EP2002/009389
Authority: WO
Inventors: Paolo Speggiorin
Original assignee: Lino Manfrotto + Co. S.P.A.
Priority date: 2001-12-12
Filing date: 2002-08-22
Publication date: 2003-07-03
Also published as: ITPD20010289A1

Abstract

Clamp comprising a first and a second jaw (3, 4) pivoted with respect to each other about an axis (x), a tightening device (9) between the jaws (3, 4) including presser means operating on the said first jaw (3) in a position spaced apart from the said axis (X) of articulation to swing the said first jaws away from or towards each other as a result of a movement of the said presser means caused by means of a threaded rod (10) connected to the second jaw (4). Restraining means are provided between the rod (10) and the second jaw (4) to receive a tightening force applied between the said jaws, these means comprising a female thread (17) movable selectively between a first, operating, position in which the said female thread (17) and the thread of the said rod (10) are engaged with each other to receive the tightening force and a second, inoperative, position in which the said female thread (17) is disengaged from the rod (10).

Description

CLAMP, PARTICULARLY FOR SUPPORTING OPTICAL AND PHOTOGRAPHIC/CINEMATOGRAPHIC EQUIPMENT

Technical field

The present invention relates to an improved clamp, particularly for supporting optical and photographic/cinematographic equipment. Technological background

Clamps of the aforesaid type are widely used in the specific field in question for fixing optical and photographic/cinematographic equipment and apparatus and various accessories to supporting elements, such as tubular sections or other similar supporting structures.

A clamp of this kind typically comprises a pair of jaws pivoted with respect to each other about an axis of articulation, a threaded rod being mounted on one of these jaws at a specified distance from the axis of articulation, while a presser element associated with the rod acts on the other jaw. When the rod is screwed in by means of a suitable knob, one jaw is made to swing away from or towards the other until the jaws are tightened on the supporting element.

Although such clamps provide effective locking of the jaws on the support, they have some limitations, including the fact that the operating knob has to be turned repeatedly in order to screw in the rod, not only during the actual tightening but also during the process of simply positioning the jaws with respect to each other, and in order to unscrew the rod and move the jaws away from each other. This operation of positioning the jaws with respect to each other (both when the jaws are brought together and when they are moved away from each other) is therefore relatively slow and impractical, especially when the clamp has to be tightened frequently or when large numbers of clamps have to be tightened.

Description of the invention

The fundamental problem of the invention is that of providing a clamp whose structural and functional design is such that the limitations of the aforementioned prior art can be overcome.

This problem is resolved by the invention by means of a clamp made in accordance with the following claims. Brief description of the drawings Further characteristics and advantages of the invention will be made clearer by the following detailed description of a preferred example of embodiment thereof, illustrated, for the purpose of guidance and without restrictive intent, in the attached drawings, in which

- Figure 1 is a perspective view of a clamp made according to the present invention;

- Figure 2 is a view in longitudinal section of the clamp of Figure 1 in a first operating position;

- Figure 3 is a partial sectional view of a detail of the clamp of the preceding figures in a second operating condition.

Preferred embodiment of the invention

In the figures, the number 1 indicates the whole of a clamp made according to the present invention and intended for fastening to a tubular section 2 having a circular cross section (Fig. 2). By suitable shaping of the jaws, the clamp 1 can be used equally well on sections having different polygonal cross sections.

The clamp 1 comprises a first jaw and a second jaw, indicated by 3 and 4 respectively, pivoted with respect to each other about an axis X. More particularly, the jaw 4 is extended rigidly by a stem 5 on which opposing side pieces 6, which are parallel and spaced apart from each other and form an extension of the jaw 3, are engaged in such a way that they can swing about the axis X.

The jaws 3 and 4 are conveniently provided with facing gripping surfaces, indicated by 3a and 4a respectively, between which the tubular section 2 is gripped. The surfaces 3a and 4a have a flat and a concave shape respectively, to enable the clamp to be effectively locked and tightened on the section 2 and on similar supports having curved surfaces.

A housing 7, for removably holding fixing elements (not shown) of equipment and/or accessories in general, is also formed in the stem 5. A screw 8, which is engaged with the stem 5 and can be screwed into the housing 7, enables the equipment to be locked by preventing the corresponding fixing element from being drawn out of the said housing.

The clamp 1 also comprises a device for tightening the jaws, generally indicated 9, including a threaded rod 10 having a longitudinal axis Y, mounted slidably in the stem 5. The rod 10 is guided axially with radial play in an axial hole 11 of a bush 11 a held on the stem 5 on the opposite side of the axis X from the jaw 4. The axis Y is therefore spaced apart from the axis of articulation X by a specified distance D and lies perpendicularly to the said axis X.

At one of its opposite axial ends, the rod 10 is rigidly connected to an operating extension 12 for the application of the tightening force between the jaws, as explained in detail in the following part of the description.

A plate element 13 is also fixed axially on the rod 10 in a position between the stem

5 and the extension 12. The said plate element 13 forms a presser means acting on the first jaw 3 when the clamp is tightened. It comprises a pressing surface 13a acting on the first jaw 3 with a contact essentially tangential to the respective curved profiles of corresponding end surfaces 6a of the side pieces 6 of the first jaw 3, as shown in Figure 2.

The number 14 indicates a blind hole formed in the stem 5 in a position such that it intersects the bush 11 a and the hole 11. A push-button element 15 is mounted slidably in the hole 14 along a direction shown by the axis Z in Figure 2, which intersects the axis Y of the rod 10.

The push button 15 projects outside the stem 5, and a through hole 16 is formed in the push button and extends parallel to the axis Y A circular sector of the hole 16 comprises a female thread 17, formed by partial threading of the said hole. This female thread sector 17 preferably extends in such a way that it surrounds not more than half of the circumferential extension of the rod 10. The rod 10 is also housed in the hole 16 with radial play in such a way that the female thread sector 17 is movable between a first, operating, position in which the female thread 17 and the thread of the rod 10 are engaged with each other and a second, inoperative, position in which the female thread is disengaged from the rod.

A spring 18 acts on the push button 15 to elastically push the female thread into engagement with the threaded rod.

The letter A in Figure 2 indicates the angle formed between the directions of the axis Y of the rod 10 and the axis Z of the push button 15. The said angle A is selected in such a way that, with specified thread angles of the rod and the female thread, the component of the pressure acting on the sides of the thread along the axis Z and due to the applied tightening force is either zero or, at the most, tending to push the female thread sector 17 towards the first operating position, in addition to the contribution made by the elastic action of the spring 18. In this case, it is certain that, regardless of the tightening force applied between the jaws, the female thread 17 will always be engaged with the thread of the rod 10 and will be disengageable only by a voluntary act of pressing the push button 15 against the action of the spring 18.

Preferably, the angle A is made to be less than or equal to 58° when the thread angles are 60°.

A second spring 19 is provided between the stem 5 and the first jaw 3 to push the jaws into a separated position by swinging them about the axis X.

Starting from the separated position of the jaws 3 and 4, the operation of the clamp according to the invention is as follows. The female thread 17 is first moved to the inoperative condition of Figure 3, by pressure on the push button 15 in opposition to the spring 18. When the push button 15 is held down, the rod 10 is freely slidable with respect to the jaw 4, so that the jaw 3 can be rapidly positioned with respect to the tubular section 2, by the free swinging of the jaw about the axis of articulation X. When the desired position has been reached, in which the surface 3a of the jaw 3 is in contact with the section 2, the push button 15 is released, and consequently the female thread 17 is moved, by the action of the spring 18, to the operating position of Figure 2. In this position, the female thread 17, engaged with the rod 10 so that the latter can be screwed in, is able to receive the tightening force. This force is applied by rotating the extension 12 so that the rod is screwed in and consequently the presser element 13 is pressed on to the side pieces 6 of the jaw 3. Because of the pivot arm formed by the distance D, the jaw 3 is moved with a swinging motion about the axis X, in the direction indicated by the arrow C of Figure 2, thus exerting the specified tightening force on the corresponding tubular section 2. The tangential contact of the presser element 13 with the jaw 3 enables the swinging of the said jaw to be conveniently limited while the tightening force is applied.

Conversely, in order to remove the clamp from the section 2, it is simply necessary to slacken the tightening force by unscrewing the rod 10 in the first place, and then to press the push button 15 in such a way as to disengage the female thread 17 from the rod 10, thus enabling the rod to slide freely and consequently allowing the first jaw to be moved rapidly away from the section 2. At this point, the return action of the spring 19 enables the said jaws to be separated rapidly from each other. Thus the invention resolves the initial problem and provides the previously claimed advantages over the known solutions. Particular mention should be given to the advantage of fast action in the operations of positioning the clamp with respect to the support to be gripped.

Claims

1. Improved clamp, particularly for supporting optical and photographic/cinematographic equipment, comprising a first and a second jaw (3, 4) pivoted with respect to each other about an axis (x), a tightening device (9) between the jaws (3, 4) including presser means operating on the said first jaw (3) in a position spaced apart from the said axis (x) of articulation to swing the said jaws away from or towards each other as a result of a movement of the said presser means caused by means of a threaded rod (10) connected to the second jaw (4), restraining means being provided between the rod (10) and the second jaw (4) to receive a tightening force applied between the said jaws, the said restraining means comprising a female thread

(17) movable selectively between a first, operating, position in which the said female thread (17) and the thread of the said rod (10) are engaged with each other to receive the tightening force and a second, inoperative, position in which the said female thread (17) is disengaged from the rod (10) to allow the said rod to slide freely with respect to the second jaw (4) and provide a rapid movement of the said jaws towards and/or away from each other.

2. Clamp according to Claim 1 , in which the said female thread (17) is formed in a push-button element (15) provided to move the said thread between the said first and second position.

3. Clamp according to Claim 1 or 2, in which the said female thread (17) extends only over a sector of a through hole (16) which is formed in the said push-button element (15) and in which the said threaded rod (10) is slidably housed.

4. Clamp according to Claim 3, comprising first elastic means (18) acting on the said female thread sector (17) to push the said sector into engagement with the thread of the said rod (10) in the first, operating, position.

5. Clamp according to one or more of the preceding claims, in which the said female thread sector (17) extends so that it surrounds not more than half of the circumferential extension of the rod (10), in such a way that it can be disengaged from the thread of the said rod (10) in the second, inoperative, position.

6. Clamp according to one or more of Claims 3 to 5, in which the said female thread sector (17) is guided slidably in a bush (11 a) mounted in a stem (5) rigidly connected to the second jaw (4), the said push-button element (15) being operable from the outside of the said bush (11 a) to move the female thread sector (17) selectively between the said first and second position.

7. Clamp according to Claim 6, in which the said rod (10) has a specified axis and thread angle, the said female thread sector (17) being guided in the said bush (11a) in a direction intersecting the said thread axis, the said direction and the said thread angle being selected in such a way that the tightening force received by the rod (10) has a component along the said direction of sliding of the female thread sector (17) which is zero or, at most, tends to push the sector into the first, operating, position.

8. Clamp according to one or more of the preceding claims, in which the said rod (10) is axially slidable in the second jaw (4) along an axis perpendicular to the axis of articulation of the said jaws (3, 4).

9. Clamp according to Claim 8, in which the said rod (10) is mounted slidably in the said second jaw (4) on the side of the axis of articulation of the said jaws remote from the jaw (4).

10. Clamp according to one or more of the preceding claims, in which the said presser means comprise a pressing surface (13a) acting on the said first jaw (3) with a substantially tangential contact with the profile of a corresponding surface of the first jaw (3).

11. Clamp according to Claim 10, in which the said presser means comprise a plate element (13) interposed between the first jaw (3) and an operating extension (12) connected rigidly to one end of the said rod (10) for operating the rod.

12. Clamp according to one or more of the preceding claims, in which are provided second elastic means (19) acting on the first jaw (3) to push the said jaw into a condition in which it is separated from the second jaw (4).

13. Clamp according to one or more of the preceding claims, in which the said second jaw (4) comprises means of attachment for equipment and/or accessories.