Clutch brake mechanism for lawnmowers

In a lawnmower of the type including a drive shaft adapted for connection to a source of rotary motion, a rotatably mounted blade, and drive system for selectively drivingly connecting the drive shaft and the blade, the improvement wherein the drive system includes a combination clutch-brake device, comprising:

• a. an input member coupled to the drive shaft and having a drive portion formed thereon including peripheral wall portions concentric about an axis;
• b. an output member coupled to the blade and positioned near said input member;
• c. said members being relatively rotatable about said axis;
• d. spring means supported on said output member for rotation therewith and extending around and in engagement with said input member to normally establish a driving connection therebetween which is operable, when said input member is rotated in a selected direction, to drive said output member;
• e. braking means for interrupting said driving connection and for braking the rotation of said output member, including:
• i. sleeve means positioned around portions of said spring means and connected to said spring means for rotation therewith;
• ii. restraining means including a spring steel brake band having a coiled central region extending around said sleeve means and also having opposite end regions extending away from said coil and intersecting substantially at right angles;
• iii. biasing means normally biasing said central region into braking engagement with said sleeve means to restrain the movement thereof to release the grip of said spring means on said input member thereby interrupting said driving connection, and to restrain the rotation of said output member;
• iv. operating means connected to said restraining means and for selectively releasing the braking engagement between said central region and said sleeve means to permit rotation of said output member;
• v. bracket means, including a bracket movably carried near one side of said sleeve means, connecting with one of said end regions for restraining the brake band against rotation with said sleeve means, said end regions extending to positions overlying said bracket, said bracket being formed from a strip of metal with opposite end portions bent away from the plane of the strip to define first and second end flanges, said bracket including a mounting hole formed therethrough near said first end flange, the connection between said one end and said mounting bracket being located along a line which is tangent to said central coiled region and extending through said mounting hole;
• vi. said operating means including a control cable connected to the other of said end regions for moving said other end region to selectively release and establish braking engagement between said coiled central region and said sleeve means, said control cable being provided with a shield secured to said first end flange;
• and
• vii. said biasing means connecting with said other end region and with said bracket to bias said other end region in a direction which will tighten the grip of said coiled central region around said sleeve means, said biasing means including a tension coil spring connected at one end to said other end region and at the other end to said second end flange.

In a lawnmower of the type including a drive shaft adapted for connection to a source of rotary motion, a rotatably mounted blade and a drive system for selectively drivingly connecting the drive shaft and the blade, the improvement wherein the drive system includes a combination clutch-brake comprising:

• a. an input member defining a cylindrical input surface coaxially coupled to the drive shaft;
• b. an output member defining cylindrical output surface coupled to the blade, said output surface having a diameter substantially the same as said input surface and being coaxially carried adjacent said input surface;
• c. a clutch spring wrapped around said surfaces for selectively establishing a driving connection between said surfaces;
• d. a sleeve carried coaxially about a portion of said clutch spring and coupled to one end region thereof for rotation therewith, said sleeve being operable, when braked and when released to establish and release said driving connection;
• e. a brake band having a coiled central region extending around said sleeve and having opposite end regions extending away from said coiled region;
• f. support means connected to one of said end regions for restraining the said brake band against rotation while permitting limited movement of said one end region so said coiled region can self-center about said sleeve;
• g. biasing means interposed between the other of said end regions and said support means for tightening the coiled region of said band around said sleeve;
• and,
• h. control means connected to said other end region for moving said other end region in opposition to the action of said biasing means to release said coiled region from said sleeve whereupon said clutch spring establishes a driving connection from said drive shaft to said blade.

A combination clutch-brake device comprising:

• a. an input member having a drive portion formed therein including a cylindrical input surface concentric about an axis;
• b. an output member positioned near said input member;
• c. said members being relatively rotatable about said axis;
• d. spring means supported on said output member for rotation therewith and extending around and in engagement with said input surface to normally establish a driving connection between said members which is operable, when said input member is rotated in a selected drive direction, to drive said output member;
• e. braking means for interrupting said driving connection and for braking the rotation of said output member, including:
• i. sleeve means positioned around portions of said spring means and connected to said spring means for rotation therewith;
• ii. restraining means including a brake bank having a coiled central region extending around said sleeve means and opposite end regions extending away from said coiled region;
• iii. bracket means, including a bracket movably carried near one side of said sleeve means, connected to one of said end regions for restraining said band against rotation with said sleeve means, said end regions extending to positions overlying said bracket;
• iv. biasing means connected to the other of said end regions and to said bracket means to bias said other end in a direction which will tighten the grip of said coiled region around said sleeve means to restrain the movement thereof to release the grip of said spring means on said input member thereby interrupting said driving connection, and to restrain the rotation of said output member;
• and,
• v. operating means connected to said other end region for moving said other end region to selectively release and engage said coiled region with said sleeve means.