Method of mounting a transducer to a driveshaft

Abstract

A method of mounting a transducer to a driveshaft which eliminates the need for a transducer housing, the improved method directly attaches the transducer to a rigid distal tip of a drive-shaft which is part of a rotatable imaging core of a catheter assembly. The method contemplates heat treating the distal tip of the drive-shaft to make it rigid, machining the distal tip to be dimensioned to hold the transducer, and attaching the transducer to the distal tip by clamping, crimping, or an adhesive.

I claim:  
     
         1 . A method of mounting a transducer to a driveshaft comprising the steps of: 
 providing an elongate tubular element including a lumen;    providing a rotatable imaging core adapted to pass through the lumen, the imaging core including a flexible drive-shaft and a transducer;    processing the distal tip of the drive-shaft; and    attaching the transducer to the distal tip of the drive-shaft.    
     
     
         2 . The method of  claim 1  wherein the step of processing the distal tip of the drive-shaft comprises the step of hardening the distal tip by welding.  
     
     
         3 . The method of  claim 2  wherein the drive-shaft is made of flexible wound wires and wherein the step of hardening the distal tip by welding joins the wound wires of the distal tip together such that a rigid distal tip is formed.  
     
     
         4 . The method of  claim 2  wherein the step of hardening the distal tip by welding includes the step of applying electrodes at two locations on the drive shaft for electrical conductivity therebetween.  
     
     
         5 . The method of  claim 1  wherein the step of processing the distal tip of the drive-shaft comprises the step of hardening the distal tip by soldering.  
     
     
         6 . The method of  claim 1  wherein the step of processing the distal tip of the drive-shaft comprises the step of hardening the distal tip with an adhesive.  
     
     
         7 . The method of  claim 5  wherein the drive-shaft is made of flexible wound wires having interstices therebetween and wherein the step of hardening the distal tip by soldering fills a substantial amount of the interstitial spaces such that a rigid distal tip is formed.  
     
     
         8 . The method of  claim 5  further comprising the step of using a cold clamp having a high specific heat to dissipate excess heat during soldering.  
     
     
         9 . The method of  claim 5  further including inserting a plug into the lumen in order to keep the lumen open during soldering.  
     
     
         10 . The method of  claim 9  wherein the plug is ceramic.  
     
     
         11 . The method of  claim 9  wherein the plug is a piece of fiber-optic.  
     
     
         12 . The method of  claim 1  wherein the step of processing the distal tip of the drive-shaft comprises the step of grinding the distal tip to form an arcuate recession with opposing tapered side walls.  
     
     
         13 . The method of  claim 1  wherein the step of processing the distal tip of the drive-shaft comprises the step of milling the distal tip to form an arcuate recession with opposing tapered side walls.  
     
     
         14 . The method of  claim 1  wherein the step of attaching the transducer to the distal tip of the drive-shaft comprises the step of crimping the tapered side walls about the perimeter of the transducer so that the transducer is held in place therebetween.  
     
     
         15 . The method of  claim 1  wherein the step of attaching the transducer to the distal tip of the drive-shaft comprises the step of providing a clamping member to attach the transducer to the distal tip of the drive shaft.  
     
     
         16 . The method of  claim 15  wherein the clamping member is fixedly attached to the drive-shaft and removably attached to the transducer.  
     
     
         17 . The method of  claim 1  wherein the step of attaching the transducer to the distal tip of the drive-shaft comprises the step of using an adhesive to attach the transducer to the distal tip of the drive-shaft.  
     
     
         18 . The method of  claim 17  wherein the adhesive is a UV cure epoxy.  
     
     
         19 . The method of  claim 1  wherein the lumen is configured to allow the passage of the rotatable imaging core.  
     
     
         20 . The method of  claim 1  further comprising a generally cylindrical imaging window.  
     
     
         21 . The method of  claim 1  wherein the transducer has a generally circular surface.  
     
     
         22 . The method of  claim 1  wherein the elongate tubular element further includes a second lumen  
     
     
         23 . The method of  claim 22  wherein the second lumen is adapted to house a steering pullwire.  
     
     
         24 . An ultrasonic imaging catheter assembly comprising: 
 an elongate tubular element including a lumen;    a rotatable imaging core adapted to pass through the lumen, the rotatable imaging core including a flexible drive-shaft attached to a transducer;    wherein the driveshaft has a distal tip adapted for mounting to the transducer.    
     
     
         25 . The ultrasonic imaging catheter assembly of  claim 24  wherein the transducer is mounted to the distal tip by soldering.  
     
     
         26 . The ultrasonic imaging catheter assembly of claim of  claim 25  wherein a cold clamp having a high specific heat is used to dissipate excess heat during soldering.  
     
     
         27 . The ultrasonic imaging catheter assembly of claim of  claim 26  wherein the cold clamp is made of aluminum.  
     
     
         28 . The ultrasonic imaging catheter assembly of claim of  claim 26  wherein the cold clamp is made of copper.  
     
     
         29 . The ultrasonic imaging catheter assembly of  claim 25  further including a plug for keeping the lumen open during soldering.  
     
     
         30 . The ultrasonic imaging catheter assembly of  claim 29  wherein the plug is ceramic.  
     
     
         31 . The ultrasonic imaging catheter assembly of  claim 29  wherein the plug includes a piece of fiber-optic.  
     
     
         32 . The ultrasonic imaging catheter assembly of  claim 24  wherein the distal tip of the drive-shaft is welded to be rigid.  
     
     
         33 . The ultrasonic imaging catheter assembly of  claim 32  wherein the rigid distal tip of the drive shaft has an arcuate recession with opposing tapered side walls.  
     
     
         34 . The ultrasonic imaging catheter assembly of  claim 33  wherein the tapered side walls are crimped about the perimeter of the transducer so that the transducer is held therebetween.  
     
     
         35 . The ultrasonic imaging catheter assembly of  claim 24  wherein a clamping member is used to removably attach the transducer to the distal tip of the drive-shaft.  
     
     
         36 . The ultrasonic imaging catheter assembly of  claim 24  wherein an adhesive is used to attach the transducer to the distal tip of the drive-shaft.  
     
     
         37 . The ultrasonic imaging catheter assembly of  claim 36  wherein the adhesive is a UV cure epoxy.  
     
     
         38 . The ultrasonic imaging catheter assembly of  claim 24  wherein the lumen is configured to allow the passage of the rotatable imaging core.  
     
     
         39 . The ultrasonic imaging catheter assembly of  claim 24  further comprising a generally cylindrical imaging window.  
     
     
         40 . The ultrasonic imaging catheter assembly of  claim 24  wherein the transducer has a generally circular surface.  
     
     
         41 . The ultrasonic imaging catheter assembly of  claim 24  wherein the elongate tubular element further includes a second lumen.  
     
     
         42 . The ultrasonic imaging catheter assembly of claim  41  wherein the second lumen is adapted to house a steering pullwire.