Patent Publication Number: US-2022214601-A1

Title: Clamping mechanism

Description:
This invention claims priority based on a U.S. provisional application Ser. No. 63/025,122 filed May 14, 2020 titled Clamping Mechanism whose teachings are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to an improved clamping (locking) mechanism assembly suitable, and, by way of example, is shown to be applicable in a camera swivel ball head mount control system. 
     BRIEF SUMMARY OF THE INVENTION 
     In an embodiment of the invention, a clamping mechanism is coupled between a swivel ball and a housing to control their relative movement. Clamping mechanisms embodying the invention include first and second gear-pawl assemblies to selectively clamp (lock) the swivel ball and the housing relative to each other or unclamp (unlock) the swivel ball and the housing relative to each other. Rotational forces are selectively applied to the gear-pawl assemblies to cause vertical (up/down) motion which increases or decreases the pressure exerted between the housing and the swivel ball. 
     In accordance with the invention, a clamping mechanism for selectively locking or unlocking a swivel ball and a housing relative to each other includes a threaded compression screw secured to the housing such that it can rotate freely but cannot move vertically (relative to the housing and swivel ball) and first and second gear-pawl assemblies, located within the housing, between the housing and the swivel ball. The first gear-pawl assembly includes a first gear and the second gear-pawl assembly includes a second gear. Each one of the first and second gears has internal threads corresponding to the threads of the compression screw and is threaded onto the compression screw. The first and second gears have respective external teeth formed around their outer periphery for the application of rotational forces to the gears. Externally generated forces (e.g., buttons with their respective link arms) apply rotational forces to the first and second gears causing the gears to selectively move apart from each other or towards each other along the compression screw. The lock/unlock mechanism may include push buttons, or any like control element, which can be operated (e.g., pushed, triggered or switched) with just one finger of a hand, to generate the external forces. 
     In a preferred embodiment, the first gear is keyed to the compression screw so they both turn and rotate together. Then, when external rotational forces are applied to the first gear, the compression screw is rotated and the second gear moves down along the compression screw increasing the spacing (i.e., distance) between the first and second gears. Increasing the spacing (distance) between the first and second gears causes increased pressure to be applied between the swivel ball and the housing tending to prevent motion (lock) between the swivel ball and the housing relative to each other. External rotational forces may be applied to the second gear to cause it to move up along the compression screw, thereby decreasing the spacing between the first and second gears. This, decreases the pressure between the swivel ball and the housing. The external forces can be applied until the swivel ball and the housing are unlocked and can move freely relative to each other. When the ball and housing are “unlocked”, the housing may be rotated or swiveled to any desired position and then subsequently locked. 
     The clamping mechanism is “jamming” resistant when rotational forces to lock and unlock are simultaneously applied. 
     The clamping mechanism embodying the invention produces an improved mechanical advantage and greater clamping force than known prior art schemes. 
     The present invention is illustrated for, and in, a camera application to produce a novel and improved swivel ball head mount. However, it should be understood that the inventive clamping/gearing arrangement is suitable for other applications. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings which are not drawn to scale, like reference characters denote like components, and: 
         FIG. 1A  is a highly simplified isometric line drawing of a clamping mechanism assembly  100  embodying the invention shown mounted on ball  17 ; 
         FIG. 1B  is another highly simplified isometric view of a clamping mechanism assembly  100  embodying the invention mounted on ball  17 ; 
         FIG. 2  is an exploded view of key components of a clamping mechanism embodying the invention; 
         FIG. 3  is a simplified vertical cross sectional diagram of a clamping mechanism embodying the invention mounted on a swivel ball; 
         FIG. 4  is a simplified horizontal cross sectional diagram of a gear and pawl assembly which may be used in a clamping mechanism embodying the invention; 
         FIG. 4A  is a simplified isometric diagram of a pawl assembly used to practice the invention; 
         FIG. 5  is another view of the simplified horizontal cross sectional diagram of the gear and pawl assembly of the clamping assembly embodying the invention; 
         FIG. 6  is a simplified vertical cross sectional diagram of the locking assembly embodying the invention mounted between a housing and a swivel ball; 
         FIG. 7A  and  FIG. 7B  are isometric representative drawings of two different views of a swivel ball head mount incorporating the clamping mechanism embodying the invention intended to be coupled to, and support, a camera; 
         FIG. 8A  is an exploded isometric view representation of a clamping mechanism embodying the invention to be mounted within a housing overlying a swivel ball; and 
         FIG. 8B  is an exploded isometric representation showing buttons for applying “external” forces to a clamping mechanism embodying the invention mounted within a housing overlying a swivel ball. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1A and 1B  show two different isometric views of a clamping (locking) mechanism  100 , embodying the invention, mounted on a spherical ball  17 . 
       FIG. 2  is an exploded view of key components forming the clamping mechanism  100 . A brief description of the components is as follows: 
     (1). Screw and washer  1  are used to lock an adjustment nut  2  into a top cap  3 .
 
(2) Adjustment Nut  2  is threaded into the top cap  3  and is used to fine tune a gap between a pressure cap  16  and the ball  17  during assembly.
 
(3) Top Cap  3  is fixed inside a housing  21  (see  FIGS. 7A, 7B, 8A, 8B ) with a retaining ring ( 801 ) to fix it from moving. Other retaining means could also be used.
 
(4) A pawl pivot pin  4   a  is a pin that a gear-pawl  8   a  rotates about and a pawl pivot pin  4   b  is a pin that a gear-pawl  8   b  rotates about.
 
(5) An actuation pin  5   a  enables the transfer of an input force from an actuation link  9   a  to a link arm  6   a  and an actuation pin  5   b  enables the transfer of an input force from an actuation link  9   b  to link arm  6   b . As shown in the Figures (e.g.,  FIGS. 3, 4, 6 ), a button B 1  is used to apply an input (“external”) force to link  9   a  which activates link arm  6   a  and a button B 2  is used to apply an input (“external”) force to link  9   b  which activates link arm  6   a.  
 
(6) Link arm  6   a  pivots around link pivot pin  10  and is used to transfer the input force from actuation link  9   a  to gear-pawl  8   a  and link arm  6   b  pivots around the link pivot pin  10  and is used to transfer the input force from actuation link  9   b  to gear-pawl  8   b.  
 
(7) A pawl spring  7   a  pushes on the back of the gear pawl  8   a  to keep it in contact with gear  14   a ; and a pawl spring  7   b  pushes on the back of gear pawl  8   b  to keep it in contact with gear  14   b.  
 
(8) Gear pawl  8   a  is actuated by link arm  6   a  via pawl pivot pin  4   a . Gear pawl  8   a  causes gear  14   a  to advance when its link arm  6   a  is actuated in response to the actuation of link  9   a  by an input (external) force applied to a button B 1 . Likewise, gear pawl  8   b  is actuated by link arm  6   b  via pawl pivot pin  4   b . Gear pawl  8   b  causes gear  14   b  to advance when its link arm  6   b  is actuated in response to the actuation of link  9   b  by an input (external) force applied to a button B 2 .
 
(9) As already noted, actuation link  9   a  transfers an input (external) force from a button (e.g., B 1 ) or other like device into link arm  6   a  and actuation link  9   b  transfers an input force from a button (e.g., B 2 ) or other like device into link arm  6   b.  
 
(10) A link pivot pin  10  extends between top cap  3  and pressure cap “holder”  16 . The link arms  6   a  and  6   b  pivot about pin  10 .
 
(11) A stabilizer pin  11  is used to stabilize the assembly. It is connected at its top end to the top cap  3  and at its bottom end to the pressure cap holder  16 .
 
(12) Thrust Washers ( 12   a ,  12   b ,  12   c ) are located at three locations. The top of gear  14   a  pushes against washer  12   a  which pushes against nut  2 . Washer  12   b  is located between gears  14   a  and  14   b . Washer  12   c  is located between the bottom of gear  14   b  and pressure cap  16 . The washers function to transfer the force (pressure) from the pressure cap holder  16  to the gears,  14   a  and  14   b , up to the adjustment nut  2 . When gear  14   a  is actuated (rotated) and gear  14   b  moves down away from gear  14   a  pressure cap  16  pushes on ball  17 , the force transfers from the pressure cap through  12   c , screw  13  and gear  14   a , washer  12   a , and to adjustment nut  2 . When gear  14   b  is actuated (rotated) and moves up along compression screw  13  towards gear  14   a , the pressure on pressure cap  16  is decreased and when fully retracted gear  14   b  stops on washer  12   b.  
 
     In the embodiments shown in the Figs., clamping module  100  is fixedly connected to the “main” housing  21  and gear  14   a  is fixedly connected to screw  13 . When gear  14   a  and screw  13  are made to turn (rotate), gear  14   b  moves down along screw  13  and pushes down on washer  12   c  which then pushes down on the pressure cap  16  which pushes down on ball  17  tending to lock the clamping module and the “main” housing  21  preventing motion of the housing and the ball relative to each other. Washer  12   b  is intended for a spacer and a stop for when the gears are fully retracted. That is, when gear  14   b  is fully retracted, it stops on washer  12   b.    
     (13) Compression Screw  13  is threaded into and locked against gear  14   a  and enables the assembly to expand and contract. Compression screw  13  is free to rotate (with gear  14   a ) but does not move up or down relative to the housing  21  and the swivel ball  17 .
 
(14) Gears  14   a  and  14   b  have an internal thread which mesh with the thread of compression screw  13  and are threaded onto screw  13 . In the embodiments of the invention shown here gear  14   a  is keyed to compression screw  13  and they rotate together. Gear  14   a  once mounted onto screw  13  does not go up and down. Gear  14   b  can move up and down along screw  13  and can also rotate. Gears  14   a  and  14   b  have external teeth formed along their outer periphery (and in a plane generally perpendicular to that of their internal threads). Gears  14   a  and  14   b  can rotate in response to rotation forces applied to their external teeth via their respective gear pawls  8   a ,  8   b  when their respective link arms  6   a  or  6   b  are actuated in response to input forces applied to their respective a actuation links ( 9   a ,  9   b ).
 
(15) Spring Washers  15   a ,  15   b  are optional. They may be used to keep pressure in the system for easy adjustment using the adjustment nut  2 . They also enable the application of forces onto the thrust washers ( 12   a ,  12   b ,  12   c ) to maintain compression force between gears  14   a  and  14   b.  
 
(16) Pressure Cap Holder  16  houses the internal components of the locking/unlocking mechanism  100  and is used to transfer the compression load from the gears  14   a ,  14   b  to the ball  17 . As shown in  FIG. 6 , the pressure cap holder  16  is firmly attached to main housing  21 . Thus, from  FIGS. 3 and 6  it may be seen that when pressure is applied via module  100  between housing  21  and ball  17 , the friction load between the housing  21  pressure cap  16  combination and ball  17  causes the components to lock together; i.e., it prevents motion between cap  16  and ball  17 . The load is transferred through pressure cap  16 , up through gears  14  to adjustment nut  2 . Adjustment nut  2  is threaded into top cap  3  which transfers the load into the main housing  21  through retaining ring  801  (see  FIG. 8 a   ). When the compression assembly is actuated in a “locking” mode, pressure cap  16  pushes down on the ball  17 , locking it against the housing  21 , and preventing it from moving.
 
(17) Ball joint  17  is a ball that is typically used for a camera ball mount. Ball  17  may be, for example, supported by or mounted on a separate base  171 .
 
     In the present embodiments the operation of the compression assembly is controlled by push buttons (e.g., B 1  and B 2 ). The buttons are spring loaded (see  FIG. 8B ) so they can be pushed in to actuate the assembly and then spring back. Button B 1  when depressed tends to cause clamping/locking (increases pressure to prevent relative motion between the housing  21  and the ball  17 ) and button B 2  when depressed tends to cause a decrease in pressure between the housing  21  and ball  17  easing relative motion between the housing  21  and ball  17 . As described below, a feature of the invention is that if buttons B 1  and B 2  are activated at the same time, there is no change in the relative pressure between the housing and the ball. This feature prevents the occurrence of “jamming”. Note, that other known actuating mechanisms or switches may be used to practice the invention. 
     Referring to the Figures, a description of the operation of the clamping mechanism  100  follows: 
     Housing  21  may be locked (via pressure cap holder  16 ) to ball joint  17 . With pressure cap  16  locked into place within a housing  21  (see  FIGS. 6, 7A, 7B, 8A and 8B ), pressure cap  16  and housing  21  can be clamped (locked) to ball joint  17  by operation of the clamping mechanism  100 , as follows. A user can push spring loaded retractable button B 1  which then pushes link  9   a  which then causes link arm  6   a  to be actuated. Link arm  6   a  then pushes gear pawl  8   a  against gear  14   a  and causes gear  14   a  to rotate at least one notch. In this embodiment, gear  14   a  is advanced in a counter clockwise direction when viewed from the top. This turns the compression screw  13 , which is locked to gear  14   a , in a counter clockwise direction relative to gear  14   b , which has a female thread. As a result, the internal assembly expands in that gears  14   a  and  14   b  are forced to separate and undergo greater distancing. This applies pressure to the ball  17  since gear  14   a  is fixed at its top end (see  FIGS. 2, 3, 8A, 8   b ) and gear  14   b  is forced to move down applying increasing an increasing downward pressure on pressure cap  16 . Button B 1  can be pushed repeatedly until gears  14   a  and  14   b  expand and the spacing between them increases to the point that housing  21  and ball  17  cannot move relative to each other. They then are clamped or locked to each other. (Note the choice of rotation is arbitrary and the gears and screw  13  could be made to rotate in the opposite, clockwise, direction). 
     Regarding the clamping mechanism note when the screw  13  rotates/turns (in response to the top gear  14   a  being caused to rotate by its corresponding—button pawl action) the bottom gear  14   b  moves downwards (rides vertically down) along the screw because it is prevented from rotating by the longer pawl. This causes the distance (spacing) between the two gears to increase and apply increasing pressure between housing and ball until locking occurs. When the screw  13  rotates/turns (in response to the top gear being caused to rotate by its corresponding button pawl action), the bottom gear moves vertically down (note that the bottom gear does not rotate for this condition). This causes the distance between the two gears to increase and apply increasing pressure between housing and ball until locking occurs. 
     The cross section stack up (see  FIGS. 3 and 6 ) shows the load path when the assembly is expanded. Starting at the bottom, the pressure cap housing  16  is pushing against the ball. The top of the pressure cap housing  16  is pushing against the thrust washer  12   c  and spring washer  15   b , which then transfers to the gear  14   b , then through the compression screw  13 . Since the compression screw is locked into gear  14   a , the load is then transferred through gear  14   a  and the top thrust washer  12   a , into adjustment nut  2 . The adjustment nut then transfers the load into the top cap which is fixed in housing  21 . 
     The housing  21  and ball  17  can be unlocked (unclamped) as follows. A user can push button B 2  which then pushes link  9   b  which then causes link arm  6   b  to be actuated. When link arm  6   b  is actuated it pushes the lower gear pawl  8   b  (see  FIG. 2 ) against gear  14   b . Gear  14   b  is then advanced, towards gear  14   a , in a counter clockwise direction when viewed from the top. When gear  14   b  is advanced, the assembly contracts and relieves pressure from the ball  17  (see  FIGS. 2 and 3 ). 
     If a user pushes both link arms,  6   a  and  6   b , at the same time, both gears will advance at the same time and neither expansion nor contraction of the assembly occurs. Thus inadvertent jamming is prevented. 
     The operation of the locking mechanism may be further explained with reference to  FIGS. 4, 4A and 5 .  FIG. 4  illustrates the operation of the gear-pawl rotating mechanism when no input force is applied (i.e., buttons B 1  or B 2  are not pushed).  FIG. 4A  is an isometric drawing showing the gear pawl assembly.  FIG. 5  illustrates the operation of the gear-pawl rotating mechanism when an input force is applied (i.e., buttons B 1  or B 2  is pushed in). 
       FIG. 4  is a top cross sectional view of the gear-pawl assembly taken along a horizontal slice showing how the gear pawl  8  ( 8   a  or  8   b ) and the link arm  6  ( 6   a  or  6   b ) and the actuation link  9  ( 9   a  or  9   b ) when the link arm  6  is not activated (“actuated”) by the application of an input force via button B 1  or B 2 ) to actuation link  9  ( 9   a  or  9   b ). The spring  7  ( 7   a  or  7   b ) forces and holds the gear pawl  8  into the gear  14  ( 14   a  or  14   b ) to positively engage the tooth (and teeth) of gear  14 . The contact surface  81  on the pawl gear is what contacts the gear teeth on gear  14 . (Both the top gear  14   a  and the bottom gear  14   b  have a gear pawl  8  and link arm  6  to rotate the gear.) Contact surface  61  on the link arm  6  ( 6   a  or  6   b ) engages the gear to prevent rotation of the gear when the link arm  6  is not activated. 
     For example, if the user actuates link arm  6   a , this will rotate gear  14   a  and advance the gear one tooth forward. During this action, the contact surface  61  on link arm  6   b  prevents the gear  14   b  from also rotating. This is what allows the gears  14   a  and  14   b  to rotate relative to each other, thus causing the assembly to expand. When the opposite action occurs and link arm  6   b  is actuated, the contact surface  61  on link arm  6   a  prevents the gear  14   a  from rotating and thus causing the assembly to contract. The spring  7  forces the gear pawl  8  into the gear  14  to positively engage the tooth of gear  14 . 
       FIG. 5  shows the position of the components when the link arm  6  is actuated. When a button (B 1  or B 2 ) is pushed an input force is applied to actuation link  9  ( 9   a  or  9   b ) it causes link  6  ( 6   a  or  6   b ) to pivot up so that the contact surface  61  ( 61   a ,  61   b ) is no longer in contact with gear  14  ( 14   a , or  14   b ). At the same time, gear pawl  8  ( 8   a  or  8   b ) applies pressure to gear  14  ( 14   a  or  14   b ) at contact surface  81  ( 81   a ,  81   b ). This allows the gear to rotate as the gear pawl  8  contacts the gear at surface  81 , which then advances the gear  14  counter clockwise. 
     When the actuation link  9  ( 9   a  or  9   b ) is pulled back (or pushed back by springs  810  see  FIG. 8B ), the gear pawl  8  slides back over the gear tooth on  14 , then the system is reset to the state shown in  FIG. 4 . 
       FIG. 6  shows a similar cross section to that of  FIG. 3  with the assembly installed in a housing. 
     Referring to  FIGS. 7A-7B  there is shown a swivel ball head mount  700  which includes a housing  21  and a spherical swivel ball  17 . The swivel ball head mount  700  is intended to provide support for a camera system  710  and to enable the camera  710  to be rotated and tilted. In the embodiment shown in  FIGS. 7A-7B , spherical swivel ball  17 , which may be of plastic or metal, is mounted on a stem  721  which rests on a base plate  722 . The ball  17 , the stem  721  and the base plate  722  may be formed as a single unit or as separate components which are then combined. Swivel ball  17  allows users to position the housing, and any camera mounted on the housing, to any selected position. Pedestal  721  and base plate  722  provide support for ball head  17  and enable a user to mount the assembly  700  to a tripod or to any suitable device. In the discussion to follow and in the appended claims the term “ball” or “ball joint” refers to a component such as spherical swivel ball  17  shown in these figures. 
     The housing  21  has an opening adapted to receive ball  17  which extends within the interior of housing  21 . In the embodiment shown in these figures the housing  21  overlies the ball  17  and is mounted so it can swivel about ball  17 . The housing  21  and ball  17  are mechanically coupled to each other such that the housing can be rotated and tilted (swiveled) about the ball head  17  to any desired position and then locked (clamped) in the desired position by means of the novel clamping mechanism operated by a lock button B 1  which can be operated with one finger pushing on the lock button. The housing  21  can be released (unlocked or unclamped) by operating the novel clamping mechanism via a release (unlock) button B 2  which can also be operated with one finger pushing on the release button. In the discussion above and to follow the term “housing” refers to a part containing (“housing”) components of the type shown in the Figures and the term “clamping mechanism” refers to components generally contained within the housing and which are coupled between the ball  17  and the housing  21  to control the clamping (locking) together of the ball and housing or their release so they are free to rotate relative to each other. 
     In  FIGS. 7A and 7B  a rotatable panning mechanism  716  is mounted on top of the housing  21  and is secured thereto. A camera  710  can be mounted on top of panning mechanism  716  and secured thereto via a base plate  712  and a clamp  714  connected to the panning mechanism  716  which is attached to the top of the housing  21 . Panning mechanism  716 , located between the camera  710  and the housing  21 , enables the camera to be set at a fixed viewing angle and to then be rotated 360 degrees relative to the housing  21 . 
     Referring to  FIGS. 7A, 7B  there is shown a push button B 1  which, when pushed, functions to control the clamping mechanism to selectively, gradually, and controllably tighten and lock the housing  21  to the ball  17  and a push button B 2  which, when pushed, functions to control the clamping mechanism to selectively, gradually, and controllably release and unlock housing  21  relative to the ball  17 . Push buttons B 1  and B 2  extend along an outer surface of housing  21 . They are designed to provide a relatively smooth contour to the outer surface of housing  21 . This is in contrast to protruding control knobs present in the prior art. Note that buttons B 1  and B 2  are respectively coupled to actuation links  9   a  and  9   b.    
       FIGS. 8A and 86  serve to show that clamping mechanism  100  is mounted within housing  21  and that a retaining ring  801  is installed on top of assembly  100  to hold it in place with housing  21  and prevent it from moving in the vertical direction. Clamping mechanism  100  with its pressure cap housing is fixedly held in place so it cannot rotate, move up and in the vertical direction or to the side. Clamping mechanism  100  is a modular assembly which is designed to be easily placed within the housing  21  between the ball  17  and the housing  21  and then fixedly connected to the housing. 
     A recapitulation of the embodiment illustrating the invention shown in the Figures is as follows: 
     1—The upper (top) gear  14   a  is keyed to the screw  13  and they both rotate together in a horizontal plane when the gear pawl is activated by its corresponding button, B 1 . There is no vertical motion of the screw  13  and top gear  14   a  relative to the housing  21  (or ball  17 ).
 
2—The upper gear  14   a  may have an internal thread to mount it on the screw  13 ; but once in place there is no relative motion between the top gear and the screw.
 
3—The bottom gear  14   b  has an internal thread to mesh with the screw thread.
 
4—When the screw  13  rotates/turns (in response to the top gear being caused to rotate by its corresponding—button pawl action) the bottom gear  14   b  moves downwards (rides vertically down) along the screw because it is held in place by the longer pawl. This causes the distance between the two gears to increase and apply increasing pressure between housing and ball until locking occurs. When the screw rotates/turns (in response to the top gear being caused to rotate by its corresponding button pawl action), the bottom gear moves vertically down (note that the bottom gear does not rotate during this action). This causes the distance between the two gears to increase and apply increasing pressure between housing and ball until locking occurs.
 
5—When the button pawl action corresponding to the bottom gear causes it to turn, the bottom gear rotates upwardly (rides vertically up) along the screw. This causes the distance between the two gears to decrease and apply decreasing pressure between housing and ball to unlock them and allow full movement.
 
6—The design of the threading is such that when the top and bottom gears are being caused to rotate simultaneously there is essentially no vertical motion between them—as a result if the two buttons controlling the movement of the gears are simultaneously depressed there is no “jamming” and the relationship of the housing and ball does not change.
 
7—Rotation of both gears is always in the same direction
 
8—The initial condition of the system is when the two gears are the closest to each other.
 
     It has thus been shown that the present invention relates to a clamping mechanism mounted within a housing, between the housing and a swivel ball, where the clamping mechanism can “lock” the housing and swivel ball to prevent relative motion between the housing and ball, or “unlock” the housing from the swivel ball to allow unhindered rotation between the housing and the ball. 
     As used herein, and in the accompanying claims, when referring to a housing overlying a swivel ball, (a) the housing may be mounted or coupled to the ball such that the housing can feely rotate about the ball without the ball moving (i.e., the ball can be held fixed); or (b) the ball can freely rotate in the housing (i.e., the housing can be held fixed). 
     Two gears with internal threads are mounted on a compression screw. The two gears have external teeth which are responsive to rotational input forces which can cause the two gears to move apart from each other or closer to each other along the screw. This movement of the gears is used to increase or decrease pressure enabling the locking and unlocking of selected components.