Abstract:
The invention relates to a clock comprising a clock face with hands and clockwork elements. Said clock face comprises a non-rotationally symmetric surface in the direction of rotation of the hands. The inner ends of the hands are rotatably mounted in a displaceable manner around a pivoting axis which extends in a peripheral manner with respect to the peripheral rotational axis of the hands and in a perpendicular manner with respect to the longitudinal axis of the hands. A control element is provided, enabling the hands to be pivoted in such a way that they can be displaced at an equal distance from the surface of the clock face as they go round. Said novel clock is characterized in that the hands on the inner end thereof or near thereto are rotatably mounted around a rotating axis extending in the longitudinal direction of the hands; the hands are flat in the visible region thereof; and a control element is provided, enabling the hands to be rotated around the rotational axis thereof in such a way that they can be displaced parallel to the clock face surface as they go round.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a clock with a clock face, one or more hands and a clockwork mechanism with one or more concentric motion arbors for moving the hands around a rotary axis in a clockwise direction, whereby the clock face, when viewed in the direction of clock-wise motion, has a surface which is not symmetrical to the rotation, whereby the hands run on bearings at their inner ends facing the axis of rotation of the hands in a clockwise direction, such that the hands can pivot round a pivot axis perpendicular to the axis of rotation in a clockwise direction and perpendicular to a longitudinal axis of the hands, and whereby a control is provided such that the hands can be moved in such a fashion that they rotate over the clock face at an essentially constant distance from the surface of the clock face.  
           [0002]    A clock of the type specified above is known from DE-U 299 21 231. Though this known clock provides for the motion of the clock hands over the clock face which is not symmetric when viewed in the direction of rotation by continuously keeping a constant small distance from the clock face, but the selection of hands is significantly restricted. This limitation is caused by the hands being tilted in their rotation only transversely to their longitudinal orientation, which leads to angular errors between the surface of the clock face and the surface of the hands especially in the case of two-dimensional, relatively wide hands such as are generally known, particularly in the case of large clocks. These angular errors can reach such an extent that it is difficult to read the time; moreover, the optical appearance is significantly affected by such angular errors. In practice, therefore, the known clock has narrow, rod-like hands preferably with a circular cross-section such that such angular errors of the type described above do not become apparent. However, these narrow, rod-like hands have a thin appearance which is unsatisfactory for the designer of such a clock and significantly restricts the design options. These disadvantages are particularly apparent in large clocks and therefore particularly disturbing.  
           [0003]    Thus it is the task of the present invention to provide a clock of the type described above which provides for greater freedom in the geometric design of the hands and which at the same time ensures that the current time can be clearly and precisely represented and read.  
         SUMMARY OF THE INVENTION  
         [0004]    The task is solved in the present invention by a clock of the type described above, characterized in that, the hands can be moved, at or near their inner end close to the axis of rotation in a clock-wise direction, around an additional axis of rotation running along the longitudinal axis of the hand, that the hands are two-dimensional in the areas visible and that an additional control is provided with which the hands can be rotated around their axis of rotation running longitudinally to the hand such that they move essentially parallel to the surface of the clock face during their circular path.  
           [0005]    As an essential part of the invention, the bearing arrangements and control of the hands in this clock are such as to ensure that the hands follow the progress of the surface of the face not only at an essentially constant distance but also essentially parallel to the surface. By this means, the use of wider or two-dimensional hands, as is normal for conventional clocks, especially large clocks, is possible. In this, their tilting movement around their longitudinal axis produces a constant parallel position of the hand to the surface of the clock face and an additional impressive optical effect for the observer of the clock. Simultaneously, a continuous, clear and exact representation and reading of the time is guaranteed in spite of the surface of the clock face not being symmetrical to the rotation and in spite of the wide or two-dimensional hands. In this manner the creative freedom for the geometrical design of the clock face and hands is further extended so that clocks can now be created with appearances which were previously not possible.  
           [0006]    A development of the invention suggests that the additional control is a rotating control arranged in the center of the clock and which forms a mechanical cam for each hand, the course of the curve of which is made corresponding to the course of the surface of the clock face when viewed in the clockwise direction, that each mechanical cam is formed by a stationary drive disk or drive drum with a control groove, such discs or drums being concentric with the relevant motion arbor and that a control lever in every control groove is restrained by the groove, the lever being linked to the relevant hand, whereby the relevant hand during its circular movement over the clock face is tilted around its longitudinal axis in accordance with the course of the control groove.  
           [0007]    The desired pivoting control of the hands around their longitudinal axis is achieved with relatively little additional structural cost by such a mechanical control with a cam whose control groove works in conjunction with a control lever for a hand. The essential point is that the hands require no further bearings and/or guidance outside the clock center and that the hands are not supported by the clock face. Because of the restraint of the control lever, this control needs no return springs and can operate independently of the effects of gravity, which means that the clock can be positioned independently as far as its attachment or installation is concerned. In addition, only limited friction occurs such that a clockwork mechanism with very little power can be used and which is therefore limited in size.  
           [0008]    In order to achieve a particularly compact construction, it is therefore foreseen as a matter of preference that the controls for the tilting and the additional controls for the rotation of the hands around their longitudinal axis are combined into a common set of controls. This also achieves a reduction in the number of individual components which will make the manufacture and installation of the control mechanism generally simpler.  
           [0009]    In a preferred, concrete arrangement it is foreseen that the common control mechanism for each hand is formed by a calculated mechanical curve for each hand which is in turn formed on or in the cover of a stationary, conical or truncated cone-shaped control component which is concentric with the axis of rotation of the hand over the clock face, and that a control lever for each hand is restrained by means of a pair of curved rollers with two curved rollers separated from each other in the longitudinal direction of the cam, whereby the distance of the cam from the axis of normal rotation of the hands determines the tilting position of the hands, and the gradient of the cam between the two curved rollers of the pair of curved rollers determines the rotational position of the hands in their rotation around their longitudinal axis. Thus one cam per hand provides both its suitable tilting motion and also its rotation relative to the surface of the clock face, in order to guarantee the required constant distance of the hand and the parallel position of the hand and the clock face in every position of the hand as it moves around the clock face.  
           [0010]    In order to avoid a collision between the hand and its stationary control body as the hand moves around the clock face and the during the tilting movement which results, it is foreseen that the external radial contour of each conical or truncated cone-shaped control component is shaped in such a manner that it follows the rotating cam at a constant distance. The distance is thereby suitably measured in such a manner that the hands pass over the contour of their control bodies at a small but adequate distance.  
           [0011]    The controls to be used in the clocks according to this invention can be made not only in mechanical form but in a number of alternative ways. Alternative forms of the control(s) can be made, for example with the aid of electric servo-motors or guided electromagnets or piston and cylinder units whose position is controlled, in all instances in conjunction with subsequent mechanical actuators. The control signals needed for the control mechanism in these versions could, for example, be transmitted to the control mechanism as analogue signals obtained by scanning or as digital signals called up from a data memory.  
           [0012]    In a further form of the clock it is foreseen that the means for the tilting and turning bearings for the hands, and the relevant controls are positioned on the rear side of the clock face which cannot be seen and that the hands extend outwards from the center of the clock face, then round the external radial edge of the face and then extend in front of the clock face in a radial direction preferably extending over less than half the diameter of the clock face. In this version of the clock the arrangement and the course of the hands are relatively closely related to conventional clocks, such that the particular optical attraction of a clock of this type lies particularly in the shape of the clock face and in the movement of the hands.  
           [0013]    One form of the clock alternative to the version described above foresees that the means for the tilting and rotating bearings for the hands and the related controls are arranged on the rear side of the clock face which cannot be seen and that the hands extend outwards from the center of the rear side of the clock face towards the outside and then round the radial external edge of the clock face and then radially towards the inside and then in front of the front side of the clock face in a radial direction, preferably over less than half the diameter of the clock face. In this version of the clock, the face is not only shaped differently from conventional clocks, but the arrangement and the movement of the hands are clearly different from conventional clocks. The observer can only see those sections of the hands on the external perimeter and those moving on the visible side, while the central area of the clock face on its front side can remain free of figures and control mechanisms. If the clock has several hands, differentiation, for instance into hour, minute and second hands, can be achieved by the length and/or width of the visible areas of the hands, or also by an additional or alternative coloring.  
           [0014]    In the most recently described version of the clock, there is also the possibility of adding at least one additional functional element at least in the central area of the front of the clock face over which the hands do not pass, particularly a light and/or a text or advertising vehicle and/or a decorative item. The clock in this version therefore offers at least one additional use, as well as indicating the time, which increases the attractiveness of the clock further.  
           [0015]    The face of the clock which is the subject of this invention can take many geometric shapes. A first, preferred, form foresees in this respect that the surface of the clock face is formed from two partial surfaces which intersect with each other at their base at an angle a which is not equal to 180°. In this way a clock face is created which, expressed in visual terms, has a crack in its surface. The two partial surfaces could, for example, be semi-circles or even other simple or complicated surfaces which together form the clock face. If angle a between the two partial surfaces is selected to be 90°, the clock which is the subject of this invention can be, for example, be installed in an internal corner between two walls intersecting each other at an angle of 90°; if the angle a is selected to be 270°, it is possible, for example, to install the clock on the external corner of a wall. In order to avoid sharp edges, the transition between the two partial surfaces can be rounded to a greater or lesser degree or be formed as a polygon.  
           [0016]    An alternative development foresees that the surface of the clock dial is composed of three partial surfaces with edges running radially, whereby the partial surfaces intersect with each other at their edges which run radially at an angle a which is not equal to 180°. In this version of the clock the three partial surfaces can, for example, be composed of three segments of a circle of equal size, which together form the clock face whereby this is composed of three partial clock faces in different spatial planes. If an angle a is selected to be 90° between the partial surfaces of the clock face, a clock face is produced which, for example, can be positioned in the corner of a room in which two walls and a ceiling or a floor surface intersect with each other.  
           [0017]    With respect to the angle a between the partial surfaces of the two versions of the clock explained above, the preference is for the angle to be between 90° and less than 180° or between more than 180° and 270°. If angles α from the above-mentioned ranges are used, clock faces can be formed which can be suitably mounted on internal corners or on external corners of walls or furniture or other suitable surfaces. In these cases, also, the transitions between the partial surfaces can be rounded, as mentioned above.  
           [0018]    A third alternative form suggests that the surface of the clock face, when looked at in a clockwise direction, is formed of differing wave or zig-zag shaped heights arranged in a regular or irregular pattern. It is quite possible to indicate and read the time, as required, on such surface shapes on the clock face of this type which appear to be complicated at first sight, as the hands follow both the changes in height and also any alteration in the surface orientation of the clock face due to the bearing arrangements of the hands which enable rotational and pivoting movements and due to the related controls.  
           [0019]    In order to achieve a construction of the mechanical components which drive the hands which is as compact as possible, the preference is for the clock to have a modified clockwork mechanism which is preferably suitable for remote control and for the clock-work mechanism to have the means for the pivoting and rotating bearings for the hands and the control(s) combined into an integrated clock-work drive unit.  
           [0020]    If, on the other hand, it is important for a manufacturer of the clock which is the subject of this invention to limit the expense involved in its construction and manufacture, and in particular to be able to use as many normal clock components as possible, it is alternatively suggested that the clock has a conventional clock-work mechanism and that the means for the pivoting and rotating bearing mechanism of the hands and the control(s) are combined into a secondary motion which has input arbors which are meshed with motion arbors of the clock-work mechanism.  
           [0021]    The clock which is the subject of this invention can, as described above, be designed as a wall clock; a design as a free-standing clock or as a suspended clock is also possible. The clock can be made for use indoors or, subject to the necessary weather-resistant design of the clock components or with a water-proof housing, can be made for use outside buildings in the open air. Finally, the clock which is the subject of the invention can be made to be worn on the body when manufactured on a sufficiently small scale. However, because of the special recognizeability of the optical effects on the movement of the hands achieved by the clock which is the subject of this invention, manufacture of the clock as a large clock is preferable. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0022]    The following lists examples of models of the invention which are explained by means of a drawing. The figures show:  
         [0023]    [0023]FIG. 1 illustrates a clock in an initial form, viewed from in front, but at an angle.  
         [0024]    [0024]FIG. 2 illustrates a plan view of a control mechanism for a hand as a part of the clock depicted in FIG. 1.  
         [0025]    [0025]FIG. 3 illustrates the clock in a second form with three hands, in the upper half predominantly in section and as an elevation the lower half.  
         [0026]    [0026]FIG. 4 illustrates the clock from FIG. 3 in elevation in the direction of the arrow IV in FIG. 3. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0027]    As FIG. 1 shows, the first example depicted here of a clock  1  has a face  2 , composed of three equally sized segments of a circle  21 ,  22 ,  23 . The segments of a circle  21 ,  22 ,  23  intersect with each other along their radial edges  21 ′,  22 ′,  23 ′ and each encloses an angle α of about 90°, whereby the transition from one circular segment  21 ,  22 ,  23  to the adjacent segment  21 ,  22 ,  23  is slightly rounded. The three segments  21 ,  22 ,  23  together form the surface of the clock face  20  on which FIGS.  24  in the form of roman numerals I to XII are mounted to indicate the time. In this instance the transitions between the segments, expressed as times of day, are to be found at 2 o&#39;clock, 6 o&#39;clock and 10 o&#39;clock.  
         [0028]    Because of this shape of the clock face  2 , the clock  1  can be mounted inside the upper corner of a room in which the segment  21  is parallel to a ceiling and the two segments  22  and  23  run parallel to a left and right wall, with the walls and the ceiling each enclosing an angle of 90° between the other.  
         [0029]    In addition, the clock  1  in FIG. 1 has two hands  31 ,  32  of which hand  31  is the minute hand and hand  32  is the hour hand. The hands  31 ,  32  are elongated and two-dimensional and are pointed at their outer end. They are, for instance, stamped from a sheet and can be colored. At their inner end, the hands  31 ,  32  each run in a journal  58  which extends along the longitudinal orientation of the hand and which is positioned in a rotating pivoting component  57  around an axis of rotation  131 ,  132  which can pivot in the longitudinal orientation of a hand.  
         [0030]    A dual-purpose pivoting and rotating control  5 ,  6  is arranged in the center of the clock  1  to which the hands  31 ,  32  are linked by their inner end in such a manner that they can move, each around two different axes, to be precise each around a pivoting axis  151  and a rotating axis  131 . The pivoting axis  151 ,  152  of each hand  31 ,  32  is perpendicular to the longitudinal orientation of the hand and perpendicular to the rotational axis of the hand; this allows each hand  31 ,  32  to be pivoted in the direction of the curved arrow  51 ″. The axes of rotation  131  of the rotating bearings formed by the journals  58  run along the longitudinal orientation of the hands.  
         [0031]    There are stationary control mechanisms with mechanical cams which are covered and cannot be seen in FIG. 1 inside the pivoting and rotating controls  5 ,  6 , the purpose of which is to pivot and rotate the hands  32 ,  32  relative to the clock face  2  around their pivoting and rotational axes  151 ,  152  in such a manner that the hands  31 ,  32  are guided over the clock face  2  which is not symmetric to the rotation in a clockwise direction  31 ′ while remaining always in a relatively small and as far as possible uniform distance from and parallel to the surface of the clock face  2 . In doing so, the hands  31 ,  32  must be pivoted downwards, that is to say to their lowest extent, in the region of the radial edges  21 ′,  22 ′,  23 ′ the segments  21 ,  22 ,  23 , whereas they are pivoted to reach their highest position in the region of the middle of each segment surface  21 ,  22 ,  23 . In order to maintain their position parallel to the surface, the hands  31 ,  32 ,  33  are simultaneously rotated about their axis of rotation  131  to a suitable extent. The fastest rotation of the hands  31 ,  32  around their longitudinal axis occurs when passing over the edge areas  21 ′,  22 ′,  23 ′; the rotation is correspondingly slower in the intermediate areas of the movement of the hands  31 ,  32 . The extent and speed of the rotation of the hands around their longitudinal axis is determined by a corresponding curve on the cams.  
         [0032]    A modified clock-work mechanism  4  which is not visible here is foreseen under the pivot control  5 ,  6  and which is covered by a cover  40 . The clock-work mechanism  4  is made in the form of an integrated clock-work drive unit, being combined with the pivot and rotational control  5 ,  6 , which creates the time-dependent movement and the pivoting and rotating motion of the hands  31 ,  32  required by the clock face and transmits the movement to the former.  
         [0033]    Although in the case of clock  1  the clock face  2  forms a surface which is not symmetric in the direction of the rotation of the hands  31 ,  32 , the hands  31 ,  32  still move during their rotation at a distance from the clock face  2  which is, as far as possible, constant and relatively small as well as being parallel to the surface, so that in spite of the geometrically complicated and unusual shape of the clock face  2 , a precise indication and reading of the time is guaranteed.  
         [0034]    [0034]FIG. 2 shows a plan view, partly cut away, of the dual-purpose pivot and rotational control  5 ,  6  which is placed in the center of the clock  1  as in FIG. 1, whereby for the sake of clarity only part of the minute hand  31  is shown, which is approximately in the 3 o&#39;clock position in FIG. 2.  
         [0035]    In FIG. 2 the pivot and rotating control  5 ,  6  is covered on its upper side which is facing the observer by an extensive rotating disc  50  which carries the hand  31  at its edge in its transverse pivoting joint  51  with the pivoting axis  51 ′ and in the axial pivot bearing  58  with the rotating axis  131  which coincides with the longitudinal axis of the hand in such a manner that the hand can pivot and rotate. The disc  50  is linked inside the pivot and rotational control  5 ,  6  by a linkage which is not depicted in detail with a motion arbor  41  of the clock-work mechanism  4  which is in the background and which cannot be seen, in such a way that the disc  50  moves 360° in an hour along with the minute hand  31  in a clock-wise direction  31 ′ around the axis of rotation of the hands.  
         [0036]    A stationary cam  53  is mounted under the rotating disc  50  as a stationary control mechanism, which has an aperture  54  in its center for the motion arbor  41  or for the linkage mentioned earlier. In addition, the cam  53  has in its upper side which faces the underside of the disc  50  a circumferential control groove  55 . A control lever  56  is restrained in this control groove  55  by one end whereby the other end of the control lever  56  is rigidly connected with the inner end of the pivoting component  57  carrying the hand  31 . As FIG. 2 clearly shows, the distance of the control groove  55  varies from the motion arbors  41  when looking towards the circumference. This causes the control lever  56  which is restrained in the control groove  55  to change its orientation during the rotation of the hand  31 . This orientation change in the control lever  56  is transmitted via the pivoting component  57  to the hand  31  in such a manner that the latter is correspondingly pivoted in the pivot bearing  51  around the pivot axis  51 ′ transversely to its longitudinal orientation according to the principles of levers, as is indicated by the curved arrow  51 ″ in FIGS. 1 and 3. The further the control groove  55  and the control lever  56  which is restrained in the former move away from the central motion arbor  41 , the further the hand  31  is pivoted upwards; conversely, the hand  31  is pivoted further downward, the closer the control groove  55  and the control lever  56  it restrains approach the motion arbor  41 . The required effect is achieved by adapting the shape of the control groove  55  to the shape of the clock face  2 , namely, the guidance of the hand  31 , and similarly of hand  32  not shown in FIG. 2, at a relatively small and essentially constant distance over the clock face  2  independently of the time of the day and the related position of the hands  31 ,  32  during their rotation.  
         [0037]    A stationary cylindrical control drum  63  is arranged under the rotating disc  50  and over the cam  53  as part of the additional rotational control  6 ; the stationary cylindrical drum  63  also has an aperture in its center for the motion arbor  41  or the linkage previously mentioned. In addition, the control drum  63  has a circumferential control groove  62  in its perimeter. A second control lever  59  is restrained in this control groove  62 , pointing in the direction of the perimeter of the control drum  63  at one end, which is formed by a roller  60  positioned on a stud  61 . The other end of the control lever  59  is linked rigidly with the journal  58  forming the radially inner end of the hand  31 , which is positioned in the pivoting component  57  in such a manner that it can rotate. In order to achieve the desired rotational movement of the hand  31  around its axis of rotation  131 , the distance of the control groove  62 , when seen in an axial direction, varies from the face of the control drum  63  facing the observer. This causes the control lever  59  restrained in the control groove  62  to alter its orientation during the rotation of the hand  31 . This alteration in the orientation of the control lever  59  is transferred to the hand  31  in such a manner that the latter is correspondingly pivoted in the pivoting component  57  around the pivot axis  131  according to the principles of levers, as indicated by the curved arrow  31 ″ in FIG. 2.  
         [0038]    The pivoting and rotating control  5 ,  6  contains two control grooves  55 ,  62  for each hand  31 ,  32  of the clock  1  such that each hand  31 ,  32  is suitably pivoted around its transverse axis and rotated around its longitudinal axis to a suitable degree during its passage over the clock face  2  in such a manner that the desired constant distance and the parallelism to the surface of the hands  31 ,  32  at a short distance over the clock face  2  is guaranteed. At the same time and as in conventional clocks, differential heights of the hands  31 ,  32  relative to each other and relative to the motion arbor is foreseen such that they do not contact each other when one is overtaking the other. If required, the clock  1  can naturally be provided with a second hand controlled in the same manner.  
         [0039]    An example of a clock with three hands  31 ,  32 ,  33  is shown in FIGS. 3 and 4. The clock  1  with the three hands  31 ,  32 ,  33  is shown in FIG. 3 in the upper half above the axis of rotation of the hands  30  predominantly in section, and in the lower half of FIG. 3 below the axis of rotation of the hands  30  in elevation. The clock face  2  with its surface  20  is partly visible in the background of FIG. 3; the remaining part of the face  2  is not shown in FIG. 3.  
         [0040]    At the left hand extremity of FIG. 3 is a clock-work mechanism  4  which is covered by a cover  40  such that when looking at the clock (in FIG. 3 when looking from right to left) it is not visible. In this case a total of three motion arbors  41 ,  42 ,  43  each with a gear wheel  72  extend forward, in the example of FIG. 3 therefore to the right, whereby the arbors  41  to  43  are arranged concentrically with each other. Roller bearings  79  are provided as bearings for arbors  41  to  43  to minimize bearing friction.  
         [0041]    Distinct from the clock in FIGS. 1 and 2, the clock  1  as in FIG. 3 has a combined pivot and rotational control  7  for the required pivoting and rotation of the hands  31  to  33  as required by the contours of the surface of the clock face  20 , which in this case are the same as in FIG. 1.  
         [0042]    At the right-hand end of each of the arbors  42  to  43  is a carrier disc  71  for one of the hands  31  to  33 , the carrier disc  71  being attached such that it cannot rotate. In FIG. 3 all three hands  31  to  33  are in the 12 o&#39;clock position. A control component  73  is positioned between any two adjacent carrier discs  71  and to the right of the outside right-hand carrier disc. These control discs  73  are all fixed in position and therefore do not rotate. Each control disc  73  has the shape of a flat cone or the stump of a cone with a conical cover  73 ′. A cam  75  in the form of a groove is arranged in each conical cover, the groove running around the whole of the control body  73  or its cover  73 ′ and has the shape of an oscillating curve.  
         [0043]    One of the hands  31  to  33  is flexibly anchored to each of the carrier discs  71 . For this purpose a control lever  76  forming the lower end of the hand  31 ,  32 ,  33  is positioned on the relevant carrier disc  71  in a pivoting linkage with a pivot axis  151 ,  152 ,  153 , the control lever  76  being able to pivot. The pivot axes  151  to  153  run transversely to the rotation axis of the hands  30  and transversely to the longitudinal orientation of the hand. The conical cover  73 ′ can be seen in the section and can be made with a gently rounded or spheroidal shape, whereby the rounded or spheroidal shape follows the relevant pivot axis  151 ,  152 ,  153 . Furthermore the remaining part of the relevant hand  31  to  33  is positioned in each control lever  76  so that it can rotate around an axis of rotation  131 ,  132 ,  133  which runs in the longitudinal axis of the relevant hand  31 ,  32 ,  33 . A roller carrier  78  with a pair of guide rollers  77  is attached to the bottom end of each hand  31 ,  32 ,  33  which projects from the control lever  76  radially towards the inside. The rollers of each pair of guide rollers  77  are inside the relevant cam  75  and are guided inside the latter. The guide rollers of the guide roller pair  77  have a fixed distance from each other in the longitudinal direction of the cam.  
         [0044]    When the hands  31 ,  32 ,  33  are rotated by the clock-work mechanism  4 , the guide rollers of the pairs of guide rollers  77  of all control levers  76  are moved by their appropriate cam  75  which brings about two movements of the hands  31  to  33 : a change in the distance of the cam  75  from the axis of rotation of the hands  30  to  33  causes the hands  31  to  33  to pivot around their pivot axis, which is illustrated for hand  33  by curved arrow  51 ″; a change in the slope or direction of the cam  35  causes the fingers  31  to  33  rotate around their rotational axes running in their longitudinal orientation  131  to  133 . In this manner a movement of each hand  31  to  33  is achieved whereby it moves in its rotation both at an essentially constant distance from and parallel to the surface  20  of the clock face  2 , even when this has a geometrically unusual and complicated shape as, for example, FIG. 1 clearly shows. Thus in the case of clock  1  in FIG. 3 this combined pivoting movement and rotation of the hands  31  to  33  is achieved by a combined control mechanism  7  with the control components  73  and the other parts already described. This permits a particularly compact construction with relatively few individual components.  
         [0045]    [0045]FIG. 4 shows the clock  1  from FIG. 3 in a front view in accordance with the line of sight IV in FIG. 3. In this, the view falls on the cover  73 ′ of the external or upper control component  73  to be found at the extreme right of FIG. 3. The axis of rotation of the hands  30  is visible in the center of the control component  73 , the axis of rotation of the hands  30  here being perpendicular to the plane of the drawing. In addition the circumferential groove-shaped cam  75  in the cover  73 ′ of the control component  73  is visible. This cam  75  closely follows the external contour  74  of the control component  73  in order to prevent the collision of the rotating hand, in this case the relevant hand  33 , with its control component  73  in its rotation around the axis of rotation of the hands  30 .  
         [0046]    For reasons of clarity only the hand  33  is illustrated, which is shown again in the 12 o&#39;clock position. In its radially external area the hand  33  has a two-dimensional form with a relatively large width. The hand  33  takes a form which is round in cross section towards its foot. The hand  33  lies in this part inside the control lever  76  and is positioned in the latter so that it can rotate around the axis of rotation longitudinal to the orientation of the hand  133 . The guide roller carrier  78  lies behind the control lever  76  with the guide roller pair  77  which is guided in the cam  75 . The pivot bearing with the pivot axis  153  follows further towards the center, around which the hand  33  can be pivoted in a plane perpendicular to the plane of the drawing.  
         [0047]    The clock face  2  with its corresponding clock face surface  20  which is in the background of FIG. 4 corresponds in shape to the clock face in FIG. 1. The clock face  2  in FIG. 4 also has three segments  21 ,  22 ,  23  which together form the surface of the clock face  20 . The 12 o&#39;clock position of the hand  33  shown in FIG. 4 is in the middle of the surface of the upper segment surface  21 . As the hand  33  is moved onwards in its direction of rotation by the clock-work  4 , a combined, controlled pivot movement and rotation of the hand  33  around the pivot axis  153  and the rotational axis is achieved by the pair of guide rollers  77  via the guide roller carrier  78  and the control lever  76 . The pivot position of the hand  33  and of the further hand  31  not depicted here is determined by the distance of the relevant cam  75  from the axis of rotation of the hand  30 . The nearer the cam  75  is to the axis of rotation  30 , the further the hand  33  is pivoted at its free end in FIG. 4 towards the observer, or, to put it in more general terms, towards the axis of rotation of the hands  30 ; conversely, the further the hand  33  is pivoted at its free end away from the observer or, to put it in more general terms, away from the axis of rotation of the hands  30 , the further the cam  75  is from the axis of rotation of the hands  30 . The minimum distance of the cam  75  from the axis of rotation of the hands  30  occurs in this case at the positions for 12 o&#39;clock, 4 o&#39;clock and 8 o&#39;clock; the maximum distance is in this position 2 o&#39;clock, 6 o&#39;clock and 10 o&#39;clock. The rotational position of the hand  33  around its axis of rotation  133  is determined by the slope or direction of the cam  75  between the two control rollers of the control roller pair  77 . The course of the cam is executed in such a way that such a rotation of the hand  33  around its axis of rotation  133  is produced that the hand in its two-dimensional external part is guided parallel to the clock face surface  20 . As FIG. 4 demonstrates, the greatest changes in the slope or direction of the cam  75  are to be found in the vicinities of the 2 o&#39;clock, 6 o&#39;clock and  10  o&#39;clock positions where the individual surface segments  21  to  23  of the clock face  20  adjoin. In the intermediate areas the cam  75  is flatter and has a smaller change in its slope or direction as the surfaces of the segments  21  to  23  in these areas are flat.  
         [0048]    In FIG. 4 in the region of arrows A and B, a position of the control lever  76  at  2  o&#39;clock and at approximately 5:25 respectively is indicated in addition to the  12  o&#39;clock position. In such cases the angle of rotation β is indicated, which the finger  33  takes up as its basic position (=0°).  
         [0049]    Thus the control  7  provides guidance for each of the fingers  31  to  33  by only one cam  75  for each, such that the relevant finger  31  to  33  is guided over the surface of the clock face  20  both at an essentially constant distance from and parallel to the surface.  
         [0050]    As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that we wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of our contribution to the art.