Abstract:
A crane for lifting, moving, and positioning a camera or other object. The Omni-Boom crane configuration allows much more unrestricted movement that a conventional single boom design.  
     The single boom design uses one vertical axis for azimuth pivoting movement, and one horizontal axis for up and down elevation movement. The Omni-Boom has two upright axes perpendicular to the main boom, one for a distal camera boom, and one for a proximal counterweight boom. These extra upright axes allow more horizontal freedom while maintaining the balance of the crane. Throughout this increased range of motion, the support of the camera remains level. The support can also maintain a constant camera aim azimuth rotational relationship with the base of the crane. If the base is stationary, the camera support is always aimed in the same direction, on the horizontal plane, if desired. Having rotational consistency, combined with greater freedom of horizontal motion, this crane offers unique possibilities for camera movement and control.

Description:
RELATED APPLICATION  
       [0001]    This application claims priority to provisional application Serial No. 60/290,731, filed May 14, 2001. 
     
    
     
       TECHNICAL FIELD  
         [0002]    The present invention relates generally to camera booms and support cranes, and more particularly to a unique mechanical configuration that provides unique freedom and control for use in supporting a motion picture or video camera or the like in a substantially “weightless” counterbalanced manner.  
         BACKGROUND OF THE INVENTION  
         [0003]    Camera support platforms for use in the motion picture industry are well known in the prior art. Such booms or cranes enable the camera operator to move in various directions within a restricted area to facilitate various camera angles and shots.  
         PRIOR ART  
         [0004]    These devices typically include some form of jib arm mounted to a movable dolly. While these prior art cranes have proved generally useful, often they do not enable the camera to move in a straight manner without also moving the dolly. Moreover, the jib arm is normally supported in such way as to limit the overall freedom of movement, especially adjacent the dolly.  
           [0005]    Examples of the single boom design represented in FIG. 1 are shown in U.S. Pat. Nos. 5,781,814; 6,217,236B1; and 5,940,645. U.S. Pat. Nos. 5,781,814 and 6,217,236B1 are refined designs of the single boom with integrated leveling assemblies to provide greater strength and easier set up and tear down. U.S. Pat. No. 5,940,645 is a simplified single boom representation with an added manual control for up and down tilting of the camera.  
           [0006]    U.S. Pat. No. 5,531,412 shows a design allowing for various camera distance from the base of the crane. This is achieved by the use of two additional horizontal axes, one for the camera arm and one for the counterweight arm. To move the camera in a straight line, raising and/or lowering of the main boom is required. To bring the camera close to the base of the crane, more height is required, similar to single boom designs. Each time the crane is rotated on its single vertical axis, the aim azimuth of the camera changes.  
           [0007]    The Weaver Steadman “8 Ft. Multi-Axis Jib Arm” that is advertised in  The American Cinematographer Magazine  November 1995 issue on page 11 maintains a level mounting for one extra vertical axis.  
           [0008]    Around this constantly vertical axis rotates an arm that carries the camera at one end and a counter-weight for the camera at the other end. This adds weight to the distal end of the crane and therefore to the proximal main counterweight of the crane. The camera can only be raised or lowered to the extent of the main boom. The aim azimuth of the camera changes each time the main boom or the camera arm is moved.  
           [0009]    It is therefore desirable to provide a camera support platform that overcomes these and other problems associated with the prior art.  
         BRIEF SUMMARY OF THE INVENTION  
         [0010]    It is an object of the present invention to provide a camera suspension apparatus that isolates the weight of the camera from that of the camera operator and provides total freedom of movement within the spatial area adjacent the apparatus, with the operator either at the camera itself or at the back of the crane, for full freedom of camera elevation.  
           [0011]    It is another object of the present invention to provide a camera suspension apparatus that has a stable base for support that allows the operator to move the camera in a straight line without moving the support.  
           [0012]    It is yet another object of the present invention to provide a camera suspension apparatus that, if the base remains stationary, maintains a constant parallel aim azimuth direction at the camera support. This constant parallel aim azimuth can be maintained if desired throughout all possible positions and movements of the invention.  
           [0013]    It is still another object of the invention to provide a camera suspension apparatus which is portable and easy to set-up and use, and which is formed of lightweight yet rigid materials for increased stability and reduced maintenance.  
           [0014]    It is yet another object to provide a suspension apparatus having a plurality of arms which pivot relative to each other upon pivot assemblies that also serve as structural supports. These and other objects of the invention are provided in a suspension apparatus that enables an operator to make fluid camera movements without himself holding up the weight of the camera.  
           [0015]    The invention accordingly comprises the features of construction, combinations of elements, and arrangements of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims. 
       
    
    
     THE DRAWINGS  
       [0016]    For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in connection with the accompanying drawings, in which:  
         [0017]    [0017]FIG. 1 is a top plan diagram of a prior art single boom crane, pivoted to different positions;  
         [0018]    [0018]FIG. 2 is a similar top plan diagram of an Omni-Boom Crane, pivoted to several different positions;  
         [0019]    [0019]FIG. 3 is a schematic side elevation diagram of an Omni-Boom Crane elevated above a horizontal position;  
         [0020]    [0020]FIG. 4 is a top plan diagram of the boom-positioning components of the Omni-Boom Crane of FIG. 3, with various structural features omitted for clarity;  
         [0021]    [0021]FIG. 5 is a partial perspective view of the Omni-Boom of this invention showing its base and boom support assembly;  
         [0022]    [0022]FIG. 6 is a partial side perspective view of the proximal counterweight end of the same device;  
         [0023]    [0023]FIG. 7 is a partial side view of the distal camera supporting boom assembly of the device;  
         [0024]    [0024]FIG. 8 is a fragmentary enlarged side view of the pivot assembly joining the distal camera supporting boom to the main boom;  
         [0025]    [0025]FIG. 9 is a fragmentary enlarged front-top perspective view of the gimbal mount at the distal end of the camera supporting boom from which a vertical post depends to carry the camera mount, and  
         [0026]    [0026]FIG. 10 is a fragmentary enlarged side-bottom view of the same gimbal mount and depending vertical post. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]    The mechanical advantages of the extra perpendicular pivot axis and rotational consistency are represented in FIGS. 1 and 2. FIGS. 1 and 2 are simplified to represent only movement and balance. FIGS. 1 and 2 show movement on only the horizontal plane. FIG. 1 is a single boom crane configuration. Point  10  represents a vertical axis or swivel point that is supported by the base of the crane. Boom  12  rotates around point  10 . A counterweight  16  is at one end of the boom and a camera support  18  is at the other end. Point  10  is at the center of a horizontal axis on which a crane is balanced. Therefore, point  10  is the balance point or fulcrum of the simplified crane of FIG. 1. With the base of such a crane stationary, the horizontal movement of the camera is limited to a circle  14  determined by the length of the boom  12 . The camera support to counterweight relationship is constant. The aim azimuth  20  in which the support is pointed, changes constantly as the boom  12  is rotated. A remote camera control head must be used between the support  18  and a camera in order to control the horizontal aim azimuth of the camera. This aim azimuth can be difficult to control and/or maintain when the boom  12  is being rotated.  
         [0028]    [0028]FIGS. 2, 3 and  4  are representations of the Omni-Boom, a three boom configuration with rotational linkage between the base and camera support.  
         [0029]    The three booms are a main boom  26 , a camera boom assembly  54  and a counterweight boom  48 . Camera boom assembly  54  is pivotally supported at the distal end of boom  26 , pivoting about an upright axis  34  perpendicular to boom  26 . Counterweight boom  48  similarly pivots about perpendicular axis  56  at the proximal end of boom  26 , as shown in FIGS. 2 and 3.  
         [0030]    Assembly  25  is the boom support assembly mounted on the base  23  of the crane, which preferably rests on lockable wheels and may thus be clamped in a fixed position. Assembly  25  supports the main boom  26  at horizontal axis  70  on which the crane is balanced, therefore horizontal axis  70  is the fulcrum or balance point. Assembly  25  surrounds a vertically extendible shaft assembly  27  that is mounted on the base  23  of the crane. If the base of the crane is stationary, the shaft assembly  27  within assembly  25  remains stationary, regardless of the rotation of main boom  26  around base assembly  23 .  
         [0031]    A timing belt pulley  28  is attached to the main boom  26  just above assembly  25  by a shaft that is held in a linear-rotary bearing. This shaft is connected to a double universal joint that is centered on axes  70 ,  24  and the central axis  29  of main boom  26 . The other end of this double universal joint is connected to the shaft  27  surmounting the base  23  of the crane. The linear rotary bearing is used to accommodate the linear difference between a single axis bend (axis  70 ) and a double axis bend (the double universal joint). Fulcrum timing belt pulley  28  is connected to one of two timing belt pulleys  30  at the distal end of boom  26  by a timing belt  32 . Timing belt pulleys  30  are two ganged timing belt pulleys of the same diameter, connected one directly on top of the other, with bearings allowing them to rotate together on a distal axis  34 , perpendicular to boom  26 . A timing belt pulley  36  at the distal end of camera boom assembly  54  is connected by a timing belt  38  to the other of the timing belt pulleys  30 .  
         [0032]    Timing belt pulley  36  rotates about a third perpendicular axis  40 , and is connected to camera support  42 , through swivel point  41  (FIG. 4) by a linear-rotary bearing double universal joint assembly similar to the one aforementioned, combined with a gimbal assembly  80  (FIGS. 3, 9 and  10 ) from which a second vertical post  78  is suspended, parallel to a first vertical post  74  suspended from the distal end of main boom  26 . Thus, a rotational, or parallel aim azimuth relationship is established between timing belt pulley  28  and camera support  42 . Arrow  44  represents one possible direction and assumes that pulley  28  will remain stationary.  
         [0033]    Camera support  42  is thus supported by a camera support boom  55 , a component of camera boom assembly  54 .  
         [0034]    Two timing belt pulleys  46  and the boom  48 , carrying a counterweight  50 , are supported by bearings in the proximal end of boom  26 , for rotation around perpendicular pivot axis  56 . Timing belt pulley  52 , boom  54 , and camera support  42  are supported by bearings at the distal end of boom  26 , for movement around first upstanding perpendicular axis  34 . A wide timing belt  64  connects distal timing belt pulley  52  to proximal timing belt pulley  46 . When camera support  42  is moved, belt  64  and its timing pulleys move counterweight  50  in the opposing direction, and visa-versa. Therefore the camera support to counterweight relationship remains constant, balanced about fulcrum  70 . On a horizontal plane, the possible placement and movement of the camera support is represented by the space between circle  60  and circle  62  in FIG. 2. Mechanical brakes are used at each vertical and horizontal axis of the configuration; allowing the Omni Boom crane to be ‘frozen’ in any position.  
         [0035]    A first vertical post  74  depends from the distal end of main boom  26 , connected for pivoting movement about a transverse horizontal axis  82  (FIGS. 3 and 4). Connector spacer arm means  72  pivoted on a central horizontal axis on boom support assembly  25  and on a distal transverse horizontal axis at the lower end of post  74  parallel to axis  82  maintains post  74  vertical.  
         [0036]    Another smaller level maintaining arm means  76  is rotationally hinged at both ends between vertical post  74  and the similar depending camera support vertical post  78 . From above, as shown in FIG. 4, both level maintaining booms  72  and  76  are preferably triangular in configuration. The rear ends of the pair of connector spacer arms  72  are mounted further apart at the boom support assembly  25  and closer together at the vertical post  74 . The rear ends of the pair of level maintaining arms  76  are also mounted further apart pivoted on an independent horizontal axis  83  for greater lateral strength at the vertical post  74  and closer together at the vertical camera post  78 .  
         [0037]    Leveling boom  76  is angled to provide space for the camera when the boom crane is raised or lowered to its maximum angle of 60 degrees. Because of the angular difference between the rotations of the camera boom assembly  54  and the leveling boom  76 , a gimbal mount  80  is used at the axis  40  end of boom  54  to suspend post  78 . This gimbal mount allows for omni directional hanging of post  78  while maintaining the height of this post.  
         [0038]    As shown in FIG. 3, two parallelograms maintain depending posts  74  and  78  vertical. Boom  26 , arm means  72 , support assembly  25  and post  74  form the first parallelogram, and post  74 , post  78 , leveling arm means  76  and camera support boom  55  form the second parallelogram, in effect.  
         [0039]    Geometrically speaking, the center point or intersection of axes of the gimbal mount  80 , axis  82 , the main transverse horizontal axis  70  at column  24  and the center of the counter weight  50  are always on the same plane parallel to axis  29  of boom  26 . Rotation of booms  54  and  48  can be powered by motor  84  that drives belt  64  through gears  86 . A manual rotation of the booms  54  and  48  by a bearing mounted timing belt pulley and handle assembly  100  is possible, and the camera may be controlled directly at camera mount  42 . A rotational relationship is established between the camera and the base of the crane. That is, while the main boom  26  and the extension boom  54  are rotated on their axes, independently or simultaneously, the camera head mount will stay aimed in the same parallel-aim azimuth direction (FIG. 2). This is achieved by mechanical connections, consisting of a double universal joint (not shown) within the gimbal mount  80 , a shaft held within a linear rotary bearing, timing belt pulley  36 , timing belt  38 , and a similar linear rotary bearing double universal joint assembly that runs through the center of axis  70  down the internal shaft  27  to the non rotating base  23  of the crane, in its fixed position mode.  
         [0040]    In addition to a full base to camera rotational relationship, two other alternative rotational relationships can be separately established. By removing timing belt  32 , and locking the pulleys  30  to main boom  26 , a main boom to camera rotational relationship is achieved with no relation to base  23 . By removing timing belt  32 , and locking the pulleys  30  to camera support boom  55 , a non-rotational relationship between camera and all booms is established. To rotate the camera in relation to camera support boom  55 , a remote camera control head must be used between the camera mount  42  and camera  21 .  
         [0041]    This design requires a strong main boom  26 . To reinforce this boom, cable  92  is added and is tightened through a system using locking pulleys  94 , mounted at the outer ends of compression spreader struts to produce stiffening diamond stay assemblies, shown in FIGS. 3, 5 and  6 . With all booms supported, all pulleys  94  are unlocked, cables  92  are tightened preferably with turnbuckles or other establishing means until all cables have equal and optimum tension, the pulleys  94  are then all locked in place to maintain optimum tension in all cables  92  while the crane is used.  
         [0042]    This Omni-Boom crane has a vertically extendable column base preferably incorporating a ball screw  27  and four extension locking legs for strength to allow more possibilities of camera placement. Control of this crane is from a handle assembly  100  mounted on a handle boom that angles above where the counterweight  50  and its boom  48  swing as the camera extension boom  54  is rotated from side to side.  
         [0043]    The systems shown to drive the extra booms  54  and  48  and to control the rotation of the camera consist of timing belts and timing belt pulleys. However, gear and driveshaft systems will be less bulky and may be less affected by bending of the booms. Gear and drive shaft systems or other mechanical means may be used to drive the camera to base rotational relationship. All axes of the crane can be powered by electric motors, and therefore, control can be computer aided and programmed, allowing complete command of camera movement. Manual control is also possible from the camera itself, including rotation of the extra booms.  
         [0044]    I believe the geometry of the mechanical connections is unique, employing three vertical axes  24 ,  74  and  78  and three upright axes  34 ,  40  and  56  perpendicular to axis  29  of the main boom  26  when boom  26  and camera boom assembly  54  are aligned. This geometry is used to maintain camera head mount level and provide rotational control in this design. Also unique is the locking pulley cable tensioning system for rigidifying and stiffening the lightweight structure. Unique software can be designed to provide computer control of a fully powered model of similar design.  
         [0045]    It will thus be seen that the objects set forth above, and those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.  
         [0046]    It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.