Abstract:
Discloses a multi-joint arm-like support including a mount connecting to an elongate first limb section by a paired ball-and-socket joint, or shoulder joint. The first limb section is connected to a second limb section by a rotatable joint or elbow joint. The second limb section has a ball-and-socket joint connecting to an instrument mount. The joints include fluid activated locks to enable the arm to be freely moveable when the fluid activated locks are released and locked in position when the fluid activated locks are activated.

Description:
FIELD OF THE INVENTION 
     This invention relates to lockable support apparatus and more particularly to a multi-joint adjustable, lockable arm-like support capable of holding tools, instruments and the like. 
     BACKGROUND TO THE INVENTION 
     Frequently certain surgical procedures make it necessary to hold a patient&#39;s body or a limb in a certain orientation or in a series of orientations that are to be fixed and maintained for extended periods, such as for example to perform orthopaedic surgery on a joint such as a shoulder or knee joint. 
     Surgical instruments have been developed that operate in co-operation with fibre optical equipment to perform surgical procedures and carry out surgical intervention with the benefit of small incisions or punctures to gain access to internal body tissues and structures to effect the surgical intervention. Use of such surgical instruments and fibre optic equipment presents the need for manipulation and holding of several instruments to effect the surgical procedure. Even a single instrument may be provided with several controls which require manual manipulation resulting in the need for additional staff or devices to hold the instrument or instruments during the course of the surgical procedure. 
     For example, U.S. Pat. No. 5,918,844 to Ognier describes a support device for a medical or surgical instrument which is adapted for use in holding instruments during surgery. Heretofore available apparatus, such as that taught by Ognier for example, has limitations of positioning and placement that reduces the desirability of such apparatus. 
     SUMMARY OF THE INVENTION 
     There is a need to have a lockable support arm that has capability for a wide range of positioning with minimal positioning limitations. 
     In one of its aspects, the invention provides a re-postitionable, lockable tool support apparatus including a base mount assembly, elongate first and second limb segments and tool mount means. The base joint has a rigidly interconnected pair of balls, each ball is in a ball and socket joint. The base joint is interconnected with the base mount assembly and to one end of the first limb. A rotating mid-joint interconnects the other end of said first limb to one end of said second limb. A remote joint interconnects the other end of the second limb to the instrument mount means. Each joint has releasable locking means operable between a locked position and a released position. 
     In another of its aspects, the invention provides a re-positionable, lockable arm-like support apparatus comprising a base including means to mount the base to a structure. The support has elongate first and second limb segments and a base joint spherically-displaceably and rotatably interconnecting said base to one end of said first limb segment. The base joint includes releasable locking means operable between a locked state where the base and the first limb segment are lockingly interconnected by the base joint. The base joint also has a released state which allows relative movement between the base and the first limb segment. The support includes a mid-joint rotatably interconnecting the other end of the first limb segment to one end of the second limb segment. The mid-joint has releasable locking means operable between a locked state, wherein the first limb segment and the second limb segment are lockingly interconnected by the mid-joint, and a released state allowing relative movement between the first limb segment and the second limb segment. The support also includes lock activation means to activate the base joint locking means and the mid-joint locking means between the locked state and the released state. 
    
    
     The preferred embodiment of the invention will now be described with reference to the attached figures in which: 
     FIG. 1 is a cross-sectional elevation view of a preferred embodiment of the inventive arm. 
     FIG. 1A is a cross-sectional elevation view of the control valve of FIG. 1 in the release position. 
     FIG. 2 is an enlarged cross-sectional view of the base joint portion of the arm of FIG.  1 . 
     FIG. 3 is an enlarged cross-sectional view of the mid-joint joint portion of the arm of FIG.  1 . 
     FIG. 4 is an enlarged cross-sectional view of the end joint portion of the arm of FIG.  1 . 
     FIG. 5 is a cross-sectional elevation view of another embodiment of the inventive arm. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a partial cutaway view of a releasable lockable re-positionable arm-like support generally depicted by reference numeral  10 . Arm-like apparatus  10  has a base  12  with mount means  11  for mounting the base to a support structure, such as an operating table or chair or wall or the like. Arm-like apparatus  10  also includes a base joint or shoulder joint  14 , a mid-joint or elbow joint  16 . Preferably arm  10  includes a remote joint or wrist joint  18 . The distal end of arm  10  provides support for items to be held in position by arm-like support  10 . For example, releasably coupled to wrist joint or end joint  18 , is a tool mount or instrument adapter  20  provided to secure the item to be held by the distal end of arm  10 . Supported by instrument adapter  20 , for example, is a surgical instrument  22 . In the configuration of the embodiment of the arm-like support apparatus  10  depicted in FIG. 1, surgical instrument  22  is mounted to the arm  10  after wrist joint  18  at the distal end of releasable lockable arm  10 . Base joint  14  is shown in a more detailed view in FIG.  2  and mid-joint  16  is shown in a more detailed view in FIG.  3 . Interconnecting base joint  14  with mid-joint  16  is a first limb segment or rigid member  24 , which is preferably tubular in construction to provide a construction which is resistant to deflection and torsion forces. Extending from mid-joint  16  is a second limb segment or rigid member  26 , which also is preferably tubular in construction to be resistant to deflection and torsion forces. In the configuration of the embodiment of the invention depicted in FIG. 1, arm-like support includes a remote joint or wrist joint  18 . 
     The releasable lockable arm  10  has a source of pressurized fluid  28  that is supplied, via supply conduit  30 , to a receiving chamber  32 . A control valve  31 , such as a conventional pneumatic valve, controls the supply of pressurized fluid from reservoir  28  to supply conduit  30 . Control valve  31  is biased into the lock configuration, to supply pressurized fluid to conduit  30 , by control valve biasing means  33 , which is for example a spring. The direction of flow of pressurized fluid from the source of pressurized fluid  28  depicted in schematic form by the lower, diagonal arrow of control valve  31 . In this configuration, or position, of the control valve  31 , releasable lockable arm  10  is locked in position. To release the arm  10  for re-positioning, control valve  31  is manipulated into the release configuration or position. FIG. 1A is a cross-sectional elevation view of the control valve  31  of FIG. 1 in the release position. In the release position, control valve  31  is manipulated by the user, such as for example by depressing a foot pedal, to reconfigure the control valve to enable supply conduit  30  to become in communication with an ambient discharge outlet  35  to discharge the pressurized fluid in supply conduit  30  and compression chamber  36  to the atmosphere. The direction of discharge fluid flow is depicted schematically by a horizontal arrow interconnecting supply conduit  30  to ambient discharge outlet  35 . Ambient discharge outlet  35  preferably includes a muffler or like device to prevent unwanted discharge disturbances such as noise and gusting or puffing. 
     Referring again to FIG. 1, in the preferred embodiment receiving chamber  32  can include apparatus serving as a pressure amplifier. To provide a pressure amplifier, slidingly disposed within receiving chamber  32  is a piston  34 . Piston  34  sealingly engages the interior surface of receiving chamber  32  to form a compression chamber  36 . Pressurized fluid in compression chamber  36  acts on piston  34  to drive it axially upwardly in the direction of arrow  38 . Connected to piston  34  is a compression shaft  40 , the distal end of which is slidingly received by housing  42 . Compression shaft  40  is in sealing engagement with housing  42  which together form a secondary fluid compression chamber  44 . Preferably, the secondary fluid filling the secondary fluid compression chamber  44  is a hydraulic fluid. An increase or amplification of fluid pressure of the fluid in secondary compression chamber  44  relative to the fluid pressure of the pressurized fluid acting in compression chamber  36  can be obtained. The increase of amplification of relative fluid pressures of the chambers is obtained by providing an end surface area of piston  34  facing into compression chamber  36  which is larger than the end surface area of compression shaft  40  facing into secondary fluid compression chamber  44 . Preferably a seal  37  is provided to seal compression shaft  40  in sliding engagement with secondary fluid compression chamber  44 . 
     The housing  42  includes a secondary fluid supply passage  46  which is normally sealed but can be opened to introduce the secondary fluid such as a hydraulic fluid into the secondary fluid passages including the secondary fluid compression chamber  44 . Secondary fluid supply passage  46  can also be used to bleed unwanted fluids, for example, air, from the secondary fluid side of the apparatus to ensure that there is an efficacious presence of secondary fluid within the secondary fluid system of the invention. 
     When the control valve  31  is manipulated into the release configuration shown in FIG. 1A, the fluid pressure in compression chamber  36  returns to atmospheric or ambient pressure. This in turn, results in removal of the force applied to compression shaft  40  and consequently ceases application of force by compression shaft  40  to the fluid contained in secondary fluid compression chamber  44 . Consequently, the secondary fluid loses pressure differential relative to the ambient or atmospheric pressure releasing the lock of the joints of the arm  10  enabling the arm  10  to be positioned or re-positioned to a desired orientation. 
     FIG. 2 provides an enlarged cross-sectional view of the base joint  14  portion of the embodiment of the releasable lockable arm  10  of FIG.  1 . The secondary fluid compression chamber  44  is in communication with a first piston chamber  48  via communicating passage  50 . A piston  53  is axially, slideably displaceable within housing  52 . Seals  55  maintain the integrity of the seal of piston chamber  48  with respect to housing  52 . The seals  55  preferably are positioned in a seal receiving groove circumscribing piston  53  to establish a seal between piston  53  and housing  52 . A first ball assembly  54  is connected to a second ball assembly  56  by means of a rigid interconnecting member  58  that prevents the relative movement of first ball assembly  54  with respect to second ball assembly  56 . Provided within rigid interconnecting element  58  is a pressure supply line  60  which extends between a first rotatable sealed coupling  62  and a second rotatable sealed coupling  64 . Pressure supply line  60  allows the pressurized fluid of piston chamber  48  to communicate with the second piston chamber  48   a.    
     The upper end of housing  62  has a collar  66  securely attached thereto. Preferably collar  66  is removable from housing  52  to effect assembly and maintenance as required. For example, collar  66  may be threadingly coupled to housing  52 . Collar  66  surrounds a girth of the ball of first ball assembly  54  and forms a seating surface  68  that mates with the exterior surface of the ball of first ball assembly  54 . When collar  66  is secured to housing  52 , the first ball assembly  54  cannot be removed from the housing  52  and collar  66  assembly as the diameter of the opening of collar  66  through which interconnecting member  58  extends is smaller than the diameter of the ball of first ball assembly  54 . However, when the coupling is not in the locked position, first ball assembly  54  is free to rotate in three-dimensional space within the housing  52  and collar  66  assembly, thereby allowing the rigid interconnecting element  58  to be rotated and/or angularly displaced relative to housing  52 . The displacement of the rigid interconnecting element  58  can include rotational displacement which includes rotation of the pressure supply line  60 . Pressure supply line  60  is sealingly coupled within housing  52  by means of first rotatable sealed coupling  62  and seals  55 . Also, when the coupling is not in a locked position, rotatable seal coupling  62  allows pressure supply line  60  to rotate within or with respect to piston  53  while maintaining a sealed relationship therewith. 
     For the other portion of the releasable lockable joint, one end of housing  52   a  has a collar  66   a  securely attached thereto. Preferably collar  66   a  is removable from housing  52   a  to effect assembly and maintenance as required. For example, collar  66   a  may be threadingly coupled to housing  52   a.  Collar  66   a  surrounds a girth of the ball of the second ball assembly  56  and forms a seating surface  68   a  that mates with the exterior surface of second ball assembly  56 . When collar  66   a  is secured to housing  52   a,  the second ball assembly  56  cannot be removed from the housing  52   a  and collar  66   a  assembly as the diameter of the opening of collar  66   a  through which interconnecting member  58  extends is smaller than the diameter of the ball of second ball assembly  56 . However, when the coupling is not in the locked position, second ball assembly  56  is free to rotate in three-dimensional space within the housing  52   a  and collar  66   a  assembly, thereby allowing the rigid interconnecting element  58  to be rotated and/or angularly displaced relative to housing  52   a.  The displacement of the rigid interconnecting element  58  can include rotational displacement which includes rotation of the pressure supply line  60  with respect to piston  53   a.  Pressure supply line  60  is sealingly coupled within housing  52   a  by means of second rotatable sealed coupling  64  and seals  55   a.  Also, when the coupling is not in a locked position, rotatable seal coupling  64  allows pressure supply line  60  to rotate within or with respect to piston  53   a  while maintaining a sealed relationship therewith. 
     Because of communicating pressure line  60 , pressurized fluid supplied from the fluid compression chamber  44  is supplied to piston chambers  48  and  48   a  simultaneously. To lock first ball assembly  54  with respect to housing  52 , a pressurized fluid, such as hydraulic fluid, is supplied to piston chamber  48 . The pressurized fluid applies a force to the area of piston  53  to urge upwardly on piston  53  in the direction of arrows  70 . As a consequence of such force, piston  53  is urged to travel upwardly until seat  72  engages first ball assembly  54  thereby compressing the ball assembly  54  between seat  72  and seating surface  68  of collar  66 . When this compression seating occurs, first ball assembly  54  is maintained in a locked configuration with respect to housing  52  thereby preventing any relative movement therebetween. In the locked configuration, interconnecting element  58  cannot move relative to housing  52 . 
     Simultaneously with the action of the pressurized fluid causing piston  53  to be urged in the direction of arrows  70 , the communicating passageway, established by first rotatable seal coupling  62 , pressure supply line  60  and second rotatable seal coupling  64 , extending to second piston chamber  48   a,  causes pressurized fluid also to be supplied to second piston chamber  48   a.  The pressurized fluid produces a force against the surface area of piston  53   a  causing it to be urged to move in the direction of arrow  70   a  thereby to urge seat  72   a  toward seat  68   a  and, consequently, compressing second ball assembly  56  therebetween. When second ball assembly  56  is compressed between seats  72   a  and  68   a,  it is rigidly held in position relative to housing  52   a.  Thus, the supply of a pressurized fluid from the secondary compression chamber  44  causes base joint  14  to become locked in position. The pressurized fluid is communicated to egress passage  74  to permit the pressurized fluid to be transmitted externally to base joint  14 . In FIG. 1, pressurized supply tube  76  carries the fluid from egress passage  74  to mid-joint  16 . Mid-joint  16  is shown in enlarged view in FIG.  3 . 
     FIG. 3 shows, in partial cut away or cross sectional view, a second rigid member  26  which is rotatably connected to first rigid member  24  through mid-joint  16 . Mid-joint  16  has a housing  78  forming a pressure chamber  80 . Pressure chamber  80  is in communication with supply tube  76 . Affixed to second rigid member  26  is a sleeve  82  rotatably disposed within pressure chamber  80 . Sleeve  82  is preferably rigidly connected to second rigid member  26 , for example, by welding to prevent axial rotational movement therebetween. Housing  78  has an upper collar  84  which forms a seat  86  in the interior thereof. Upper collar  84  rotatably receives second rigid member  26 , preferably by means of a roller bearing assembly  88  extending therebetween. When the fluid contained within pressure chamber  80  becomes pressurized, sleeve  82  is urged upwardly in direction of arrows  90 . When sleeve  82  is urged upwardly, the upper mating surface of sleeve  82  contacts with seat  86  thereby preventing relative movement between sleeve  82  and seat  86 . Because sleeve  82  is rigidly connected to second rigid member  26  and seat  86  is stationary with respect to housing  78  and first rigid member  24 , the mating engagement of sleeve  82  with seat  86  prevents the relative rotational movement of second rigid member  26  with respect to first rigid member  24 . Conversely, when the pressure is removed from the fluid filling the pressure chamber  80 , the upper mating surface of sleeve  82  is no longer forced into contact with seat  86  thereby allowing relative movement of second rigid member  26  with respect to first rigid member  24 . To maintain the integrity of the seal of the pressure chamber  80 , seals  81  are preferably indicated. 
     A passageway  92  is in communication with pressure chamber  80  to allow pressurized fluid to be delivered to wrist joint  18  through a pressure supply line formed by the interior hollow portion of second rigid member  26 . The wrist joint  18  is preferably a lockable ball joint assembly constructed and operated in a similar fashion and manner as was described in relation to each of the pair of ball joints forming base joint  14  and shown in enlarged view in FIG.  2 . 
     FIG. 4 shows an enlarged cross-sectional view of the end joint portion of the arm of FIG.  1 . End joint or wrist joint  18  has a ball  94  including a mount adapter  96  extending therefrom through collar  98 . Collar  98  forms a seat  100  in the interior portion of joint  18 , the seat dimensioned to surround a girth of ball  94 . On the other side of ball  94  from collar seat  100  is piston  102 . One end of piston  102  forms a seat  104  dimensioned to seat with ball  94 . Piston  102  is slideably received in housing  103  of end joint  18 . Preferably, a seal  105  surrounds piston  102  to prevent escape of pressurized fluid from chamber  108 . The end of piston  102  opposite seat  104  forms a surface  108  on which pressure exerted by fluid contained in chamber  108  will cause a force to be produced to urge piston seat  104  toward collar seat  100  to grippingly engage ball  94  therebetween. Increasing pressure of the fluid in chamber  108  will cause joint  18  to become in a locked state due to increasing frictional engagement of seats  100 ,  104  to ball  94 . In the locked state, joint ball  94  is prevented from moving with respect to joint housing  103 , consequently preventing any relative movement between mount adapter  96  with respect to arm second rigid member  26 . Conversely, decreasing pressure of the fluid in chamber  108  will relax the grip of seats  100 ,  104  on ball  94  enabling ball  94  of joint  18  to become released, consequently permitting mount adapter  96  to be rotated with respect to arm second rigid member  26  as well as angularly displaced with respect thereto. Preferably, second rigid member  26  is hollow to permit the pressurized fluid applied to the arm from pressure chamber  44  to be communicated to end joint  18  through  60 ,  48   a,    74 ,  76 ,  80  and  92  on its way to  26  to supply joint  18 . Alternately, second rigid member  26  can carry a pressure tube supply line (not shown) to communicate fluid pressure to end joint  18 . 
     FIG. 5 shows a partial cutaway or cross section view of another embodiment of arm support  10 . In this embodiment, a source of pressurized fluid  28  is supplied via control valve  31  to supply conduit  30  to a receiving chamber  32 . The control valve  31  is a conventional pneumatic valve, in the embodiment shown. As will be understood by those skilled in the art, a hydraulic valve may also be used, with suitable modification to the ambient discharge  35  to enable hydraulic fluid venting to be returned to a hydraulic reservoir (not shown). From receiving chamber  32 , the pressure of the fluid in supply conduit  30  is carried to other areas of the arm  10  to activate and control the locking and releasing of the joints of the arm  10 . That is the fluid pressure of supply conduit  30  is communicated to piston chambers  48  and  48   a  of base joint  14  and along supply tube  76  to pressure chamber  80  of mid joint  16  and also along the arm second rigid member  26  to supply pressure to chamber  108  of end joint  108 . When the pressure of the fluid in supply conduit  30  is increased, the joints  14 ,  16  and  18  will become locked thereby preventing relative movement of the elements of the arm  10 . When the pressure of the fluid in supply conduit  30  is decreased, the joints  14 ,  16  and  18  will become released thereby permitting relative movement of the elements of the arm  10 . The pressure of the fluid in supply conduit  30  is controlled by manipulation of control valve  31 , which, in turn, controls the locked and released state of arm  10 . 
     Now that the invention has been described with reference to the attached drawings, numerous substitutions, modifications and equivalents will occur to those skilled in the art. The invention is defined by the claims appended hereto.