Transmission mechanism for a surgical cutting instrument
First Claim
1. A tissue cutting apparatus, comprising:
- a motor driving a rotating output shaft;
an outer housing configured for insertion into a body site;
a cutting blade for cutting body tissue at the body site, the cutting blade configured for reciprocating movement within said outer housing;
transmission means disposed between said motor and said cutting blade for converting rotary motion from said output shaft to reciprocating linear motion of said cutting blade, said transmission means including;
a first cam element connected to one of said output shaft and said cutting blade, said first cam element having a cylindrical surface with a channel defined continuously around the circumference thereof;
a second cam element connected to the other of said output shaft and said cutting blade; and
a cam follower element disposed between said first cam element and said second cam element with a portion of said cam follower element slidably disposed within said channel,whereby said cam follower element traverses along said channel continuously about said cylindrical surface as one or the other of said first cam element of said second cam element rotates with said output shaft.
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Accused Products
Abstract
A reciprocating cutting instrument includes an outer tube housing an inner reciprocating cutting blade. The cutting blade is engaged to a source of power, namely a motor, through a transmission and drive mechanism. This transmission and drive mechanism converts rotary drive movement of the motor to reciprocating movement of the cutting blade. A cam is provided that engages the spindle of the motor, the cam formed by a generally cylindrically shaped cam barrel with a cam channel defined in the outer surface of the barrel. A drive ball rides within the channel and is supported within a boss of a linear in-line driver. The in-line driver reciprocates within a bearing housed by a driver cartridge. Pressure between the drive ball and the cam channel is maintained by a set screw threaded into the boss in the in-line driver. As the motor rotates, the spindle, which is engaged to the cam, rotates the cam barrel. The rotation of the cam barrel causes the cam channel to pass underneath the drive ball, which forces the drive ball to follow the channel path. In one preferred embodiment, the channel path is in the form of a harmonic curve so that the drive ball will reciprocate through a particular stroke during a full rotation of the cam.
196 Citations
9 Claims
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1. A tissue cutting apparatus, comprising:
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a motor driving a rotating output shaft; an outer housing configured for insertion into a body site; a cutting blade for cutting body tissue at the body site, the cutting blade configured for reciprocating movement within said outer housing; transmission means disposed between said motor and said cutting blade for converting rotary motion from said output shaft to reciprocating linear motion of said cutting blade, said transmission means including; a first cam element connected to one of said output shaft and said cutting blade, said first cam element having a cylindrical surface with a channel defined continuously around the circumference thereof; a second cam element connected to the other of said output shaft and said cutting blade; and a cam follower element disposed between said first cam element and said second cam element with a portion of said cam follower element slidably disposed within said channel, whereby said cam follower element traverses along said channel continuously about said cylindrical surface as one or the other of said first cam element of said second cam element rotates with said output shaft. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification