Abstract:
A tripod ( 1 ) for the support of apparatus in general and, in particular, of optical or photographic apparatus and the like is described and comprises a spider ( 3 ) in which a plurality of legs ( 2 ) converge and a pillar ( 12 ) arranged to receive the apparatus and having a stem ( 11 ) housed in a seat ( 4 ) of the spider, the seat extending through a pivotably adjustable element ( 21 ) of an articulated joint ( 22 ) formed in the spider.

Description:
CLAIM FOR PRIORITY 
   This application is a U.S. National Phase application of PCT/IT02/00201 filed on Mar. 28, 2002, which is incorporated herein by reference in its entirety. 
   TECHNICAL FIELD 
   The subject of the present invention is a tripod for the support of apparatus in general and, in particular, of optical or photographic apparatus and the like. In the following context, the term tripod is used in a broad sense to indicate a structure with three or more legs converging in a spider on which means, typically a pillar of adjustable height, are arranged for supporting the apparatus indicated above. 
   TECHNOLOGICAL BACKGROUND 
   Tripods including the above-mentioned characteristics are used widely in the photographic and cinematographic fields for the orientable support of cameras. In this field, a need arises to position the stand or tripod with the pillar support mounted thereon and to be able to orient the apparatus mounted on the pillar about its own axis. This need arises typically in so-called panoramic shots. 
   In this situation, it is necessary to position the tripod with care so that the rotation of the apparatus takes place whilst the desired state of levelness is maintained. Cinematographic tripods and stands are also known, in which, to avoid the need for levelness, supports are used which have orientable platforms on which the head that supports the optical or photographic apparatus is mounted in turn. However, these supports have no slidable central pillar, which clearly limits the height adjustment of the apparatus. 
   DESCRIPTION OF THE INVENTION 
   The main aim of the invention is to provide a support which is designed structurally and functionally to overcome all of the disadvantages discussed with reference to the prior art mentioned. 
   Within the scope of this aim, an important object of the invention is to provide an easily adjustable support. 
   This aim with these and other objects are achieved by a support formed in accordance with the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The characteristics and the advantages of the invention will become clearer from the detailed description of a preferred embodiment thereof, described by way of non-limiting example, with reference to the appended drawings, in which: 
       FIG. 1  is a perspective view of a tripod according to the invention, 
       FIG. 2  is a view showing, on an enlarged scale, a detail of the tripod of  FIG. 1 , half of which is shown in longitudinal section. 
   

   PREFERRED EMBODIMENT OF THE INVENTION 
   In the drawings, a tripod for photographic and/or cinematographic uses, generally indicated  1 , has legs  2  all of which converge in a spider  3 , a seat  4  of which houses the stem  11  of a pillar  12  in manner such that it can slide axially and can be locked in an adjustable position. 
   The stem  11  has a tubular configuration with a circular cross-section and carries, at one of its ends, a platform  13  for the fixing of the desired apparatus. A projection  14  may optionally be formed at the opposite end for preventing the pillar  12  from accidentally slipping out of the seat  4 . 
   The spider  3  has a through cavity  15  in which a conical surface  16  and a cylindrical portion  17 , part of which has a thread  18 , are identified. A ring nut  19 , in turn having a conical surface  20  facing the surface  16 , is screwed into the thread  18  in order to restrain a ball  21  pivotably in the cavity  15 . The ball  21  and the cavity  15 , with the respective conical surfaces, constitute a ball and socket joint, generally indicated  22 , of which the ball  21  is the orientable element. 
   The ball  21  can be locked in the desired orientation by means of a revolving plug  24 , the stem of which is screwed into a threaded radial hole in the spider  3 . 
   The seat  4  is formed in the ball  21 , coaxially with an externally threaded collar  21   a  projecting from the ball  21 . A cylindrical sleeve  25  arranged and restrained in the seat  4  has slots  26  at its longitudinally opposite ends for rendering the sleeve radially contractible. The stem  11  of the pillar  12  is fitted in the sleeve  25  and can be locked relative to the ball  21  by clamping means which comprise juxtaposed conical surfaces  27 ,  28  formed, respectively, in the seat  4  and in a facing position inside a ring nut  29  that can be screwed onto the collar  21   a . Screwing of the ring nut  29  onto the collar  21   a  moves the conical surfaces  27 ,  28  towards one another, resulting in radial compression of the opposite ends of the sleeve  25  and clamping thereof onto the stem  11  of the pillar  12 . The sleeve  15  is also restrained axially in the seat  4 . 
   Once the tripod  1  has been positioned and the spider  3  has been levelled approximately by positioning of the legs  2 , the revolving plug  24  is loosened in order to orient the pillar  12  in the desired manner, together with the ball  21 . The orienting of the pillar in order to level the platform  13  may be assisted by the presence of a spirit level, not shown, on the platform  13 . Tightening of the revolving plug locks the pivoting of the ball  21  relative to the spider  3 . Prior to the levelling of the pillar  12 , or afterwards, the height of the pillar  12  is adjusted by loosening the ring nut  29  so as to release the pillar for sliding axially in the seat  4 . When the desired adjustment has been reached, the ring nut  29  is tightened so as to lock the sliding of the pillar in the ball again. It is pointed out that, since the levelling is achieved by varying the position of the axis of the pillar relative to the spider, this levelling is maintained even during subsequent vertical adjustment of the pillar. 
   The invention described above enables many advantages to be achieved, amongst which the following are the most important:
     the apparatus can be levelled more quickly, by virtue of a single operation on the central pillar, rather than on the three telescopic legs of the tripod,   the apparatus retains a large degree of freedom of positioning, by virtue of the ability of the central pillar to slide vertically and to rotate, and   the apparatus retains excellent stability by virtue of the positioning of the orientable joint inside the spider, which ensures that the weight of the apparatus is vertically aligned with the spider.