Abstract:
The invention pertains to a camera tripod head comprising a camera plate ( 7 ) to be mounted on a sliding plate ( 3 ), with at least one stop ( 9 ) being releasable to the effect that the sliding plate ( 3 ) can be detached from the tripod head and replaced in the opposite direction. This makes it possible to perform a shift in the center of gravity within a larger scope.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to the technical field of camera tripods in which, taking the substantial requirements placed on camera guidance into account, care must be taken that the center of gravity of the camera has the correct relationship to the swivel and tilt movement so as to allow a flawless camera guidance throughout various swivel and tilt ranges.  
       PRIOR ART  
       [0002]     It is known that a camera is detachably attached to a sliding plate on a camera tripod head using a camera mounting plate attached to said camera, with said camera tripod head conventionally including a damping and weight compensation mechanism for the various camera movements. The detachable attachment thereby is formed by fixing means, the attachment of which limits the displacement of the sliding plate in one direction, with said displacement direction running parallel to the optical axis of the camera. The sliding plate is displaceably guided in a dovetail guide at the tripod head between two stops in conjunction with at least one counter-stop which is attached to the tripod head. In this regard, the sliding plate, which is steplessly displaceable, can be locked steplessly throughout the entire displacement range, with the partial displacement length portions starting from the tilt center of the tripod head having different lengths. This is based on the aim to keep the length of the sliding plate as short as possible so as to avoid difficulties in stowing the tripod. On the other hand, the aforementioned fixing means prevents displacement in one portion, preferably the front portion facing the lens of the camera, so that the larger displacement length is provided at the rear section given that the center of gravity of the camera usually has to be shifted backwards due to the heavy lens so as to be brought into the tilt center of the tripod head.  
         [0003]     The aforementioned stops are provided to automatically limit the displacement and thus prevent the sliding plate from becoming completely detached from the tripod head and falling together with the camera.  
       DESCRIPTION OF THE INVENTION  
       [0004]     It is the technical problem of the invention to design a camera tripod head of the aforementioned type while maintaining the particular fixing means such that the larger partial displacement length can be used to a considerable and effective extent in both displacement directions, thus allowing existing camera tripod heads to be easily refitted or retrofitted.  
         [0005]     According to the invention, this object is solved in that the sliding plate can be detached from the tripod head without using a tool and can be mounted in an opposite orientation in the direction of the optical axis of a camera to be mounted given that at least one of the displacement-limiting stops is movable as a free stop from a stop position to a release position outside the movement path with the counter-stop and back.  
         [0006]     Based on this replacement in an opposite orientation, said movable free stop allows the longer partial displacement length to become operative both in the forward and in the backward direction of the camera in a simple manner and without a need to use a tool. This allows the camera&#39;s center of gravity to be optimally shifted with respect to the tilt axis of the tripod head within an optimum wide range while maintaining a short sliding plate and without modifying the particular fixing mechanism of the existing art, i.e. not only for such cameras whose center of gravity is further towards the front but also for those cameras whose centre of gravity is further towards the back when a lighter lens is used but, for example, an electric storage battery is placed in the rear portion of the camera, which shifts the center of gravity backwards.  
         [0007]     The free stop is expediently that stop which is arranged at a distance from the fixing means limiting the displacement of the sliding plate. In connection therewith, the fixing means as such or an independent stop located in front thereof forms the limitation in one direction and the free stop forms the limitation in the other direction, with the free stop being displaceable and the sliding plate then being removable on any side. The sliding plate thus forms an interface for adjustments regarding a shoulder pad, an attachment to a body support or other possible applications of the camera irrespective of the actual camera tripod head.  
         [0008]     The free stop can be part of a hand-operated lever or part of a hand-operated pressure rod or part of a hand-operated pull rod. If the lever, the pressure rod or the pull rod is spring-loaded, the free stop can be pressed into the stop position by this spring if no actuation occurs. When actuated, the free stop is shifted to the release position against the action of the spring. This ensures in particular a rapid, uncomplicated and efficient detachability of the sliding plate. In connection therewith, the spring force as well as the actuating path can be set so as to make an unintended actuation difficult. In particular, this should be set adequately with respect to the actuating path when using a lever in which the distance between the stop as part of the lever and the lever axis is as large as possible.  
         [0009]     This ensures an increased security.  
         [0010]     An unintended actuation is made difficult even if a handle for the lever, the pressure rod or the pull rod is mounted on the sliding plate in an accessible but protected manner.  
         [0011]     The free stop can expediently be mounted on the sliding plate and the counter-stop on the tripod head, with both stops preferably being mounted on the sliding plate and the counter-stop on the tripod head. The opposite can also be the case.  
         [0012]     The free stop is preferably provided with an abutting surface, which can be formed by an inclined plane or a curve. When the sliding plate is inserted in the guidance of the tripod head, the abutting surface abuts against the counter-stop and displaces the lever, the pressure rod or the pull rod against the spring force such that the free stop will move automatically and will be movable to the stop position behind the counter-stop without actuating the lever, the pressure rod or the pull rod. So as to remove the sliding plate, it will be necessary to actuate the lever, the pressure rod or the pull rod to bring the free stop into the release position.  
         [0013]     When mention is made in this application of a sliding “plate” and a camera “plate”, this does not have to be exactly a plate. The expression encompasses any plate-like formation, even if it does not comprise flat surfaces throughout. When mention is made of the center of the tripod head, this is that location where the tilt axis and the swivel axis intersect each other. In the first place, this is the location where the tilt axis lies as such. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  shows a side view of a camera tripod head with a camera attached thereto;  
         [0015]      FIG. 2  shows a bottom view of a sliding plate of the camera tripod head;  
         [0016]      FIG. 3   a  shows a cross-sectional view along the line III-III of  FIG. 2  in an extreme displacement position; and  
         [0017]      FIG. 3   b  shows a similar cross-sectional view of the other extreme displacement position of the sliding plate. 
     
    
     DESCRIPTION OF ONE EXEMPLARY EMBODIMENT OF THE INVENTION  
       [0018]     The illustration in  FIG. 1  reveals a tripod head  1  with a camera  2  attached thereto. At the bottom side of the camera, there is an unshown camera plate which is inserted in the outer side of a sliding plate  3  and is fixedly secured by fixing means  4 . The sliding plate  3  is displaceably guided in the direction of an optical axis O of the camera  2  in the remainder of the tripod head, without the fixing point of the camera in the sliding plate  3  being modified. The respective position of the sliding plate  3  can be locked steplessly using a handle  5  and a mechanism cooperating therewith so as to align the center of gravity S of the camera  2  with a tilt axis N of the tripod head. Furthermore, the camera  2  is rotatable about a rotation axis D and pivotable about the tilt axis N, with the tilt position being steplessly fixable using a handle  5 ′.  
         [0019]     On the upper side of the sliding plate  3  there is a recess  6 , in which the camera plate  7  can be inserted and secured by the fixing means  4 . The camera can thus be detached from the sliding plate without the alignment of the center of gravity being modified by the displacement of the sliding plate.  
         [0020]     The fixing means  4  necessitates the provision of a stop  8  or a movement limiter for the sliding plate  3  in one direction, in this case to the front, taking the orientation of the camera together with its lens as a reference. A counter-stop  9  is located in the opposite direction, said counter-stop being part of a lever  10  which can be actuated by means of a handle  11 . The lever is pivotable about an axis  12 , and namely against the action of a spring  13 . In the illustration shown by solid lines in  FIG. 2 , the lever  10  is in the stop position together with the free stop  9  and, in the case of the dotted lines, it is in the free position, with the spring  13  bringing the lever  10  and the free stop  9  back to the stop position when the handle  11  is released.  
         [0021]     The sliding plate  3  is displaceable with respect to a fixed member  14 , with the total displacement path V as well as the partial displacement paths V 1  and V 2  being represented in  FIG. 3   a.    
         [0022]     Due to the provision of the fixing means  4  and the displacement limitation associated therewith, the partial displacement path V 2  is shorter than the partial displacement path V 1 . Both stops abut against a counter-stop  15 . The two extreme positions are shown in  FIGS. 3   a  and  3   b , with the fixed member  14  however being shown in a displaced manner due to the representation on one sheet.  
         [0023]     The expression “free stop” has been used for the stop  9  since it can release the stop position. In the release position illustrated by dotted lines in  FIG. 2 , the sliding plate  3  can be fully detached, without the counter-stop  15  interfering therewith. When replacing the sliding plate inversely, the long displacement path V 1  will be available in the other direction, i.e. it can be used in both directions when cameras with a greater difference in the position of the center of gravity are to be used on the tripod. So that the handle  11  does not need to be actuated when sliding the sliding plate onto the tripod head, the lever  10  is provided with an inclined abutting surface  16  which is abutted by the counter-stop  15  when the sliding plate  3  is slid onto the tripod head, thus pivoting the lever  10  against the spring force until the lever can spring back together with the free stop  9  once the counter-stop  15  has passed this region.  
         [0024]     The force of the spring as well as the path to be traveled by the free stop  9  until it has left the movement path of the counter-stop  15  can be set in such a variable manner as to prevent an unintended release of the free stop  9  as far as possible. This is also achieved as a result of the handle  11  resting as closely as possible against the sliding plate  3  so that it does not offer too large a contact surface.  
         [0025]     The system composed of a camera plate and a sliding plate can thus be maintained together with the fixing means, preferably on the side opposite the lens of the camera, while nevertheless allowing the use of the long displacement path V 1  even if a lighter lens is used and storage batteries shifting the center of gravity backwards are possibly placed at the back of the camera.  
         [0026]     This allows the existing system to be easily refitted or retrofitted.