Attachment coupling for power tool

Claim 2

A power tool assembly including a power unit and a tool attachment arranged to be coupled thereto in driven relationship comprising complementary sets of bayonet teeth respectively mounted on said power unit and said attachment for insertion of one of said sets into the other of said sets and for relative rotation of said sets into an interlocking position to couple said unit and said attachment; said power unit and said attachment each having matching piloting surfaces for aligning said attachment with said power unit upon insertion and rotation of said sets; and spring means coupling at least one of said sets to one of said power unit and said attachment for biassing said power unit and said attachment into tight engagement on said piloting surfaces upon insertion and rotation of said sets into said interlocking position whereby precise alignment of said power unit and said attachment is maintained.

Claim 3

A power tool assembly as claimed in claim 1 wherein said power unit includes a rotary drive means and said attachment includes a rotary driven means, said drive means and said driven means being coupled along an axis of rotation when said attachment is coupled to said power unit.

Claim 4

A power tool assembly as claimed in claim 2 wherein said piloting surfaces so position said attachment and said rotary means that said driven means is spaced from the stationary parts of said attachment and no bearing surface is required therein.

Claim 5

A power tool assembly as claimed in claim 2 wherein said matching piloting surfaces include a non-rotating surface on said power unit and a non-rotating surface on said attachment, each of said surfaces being in a plane perpendicular to said axis.

Claim 6

A power tool assembly as claimed in claim 4 wherein said spring means exerts a force in a direction parallel to said axis.

Claim 7

A power tool assembly as claimed in claim 5 wherein a coupling member is provided on one of said power unit and said attachment, said coupling member being engaged therewith by said spring means; and wherein one of said sets of teeth is mounted on said coupling member.

Claim 8

A power tool assembly as claimed in claim 6 wherein said teeth in at least one of said sets include a ramp surface of increasing height so that, upon insertion and rotation of said sets, said coupling member moves against said spring means toward said other of said power unit and said attachment whereby said spring means exerts a force drawing said piloting surfaces into tight engagement.

Claim 9

A power tool assembly as claimed in claim 7 wherein said coupling member is mounted on said power unit and wherein said ramp surface is provided on the teeth on said coupling member.

Claim 10

A power tool assembly as claimed in claim 4 wherein said piloting surfaces further include non-rotating radially-abutting surfaces on each of said power unit and said attachment.

Claim 11

A power tool assembly as claimed in claim 9 wherein said piloting surfaces further include axially-abutting rotary surfaces on said power unit and said attachment.

Claim 12

A power tool assembly as claimed in claim 10 wherein said piloting surfaces further include radially-abutting rotAry surfaces on said power unit and said attachment.

Claim 13

A power tool assembly as claimed in claim 11 wherein said piloting surfaces so position said attachment and said rotary means that said driven means is spaced from the stationary parts of said attachment and no bearing surface is required therein.

Claim 14

A power tool assembly as claimed in claim 1 wherein said teeth in at least one of said sets are provided with a ramp surface, said surface producing a bias in said spring means upon said rotation of said teeth whereby said power unit and said attachment are drawn together by said bias.

Claim 15

A power tool assembly including a power unit and a tool attachment arranged to be coupled thereto in driven relationship comprising complementary sets of bayonet teeth respectively mounted on said power unit and said attachment for insertion of one of said sets into the other of said sets and for relative rotation of said sets into an interlocking position to couple said unit and said attachment; one of said sets including teeth having a ramp surface of increasing height in a direction to cause tight engagement of said unit and said attachment upon said rotation; one of said sets being coupled to one of said power unit and said attachment by a spring means, said spring means being disposed to be displaced from its unstressed configuration by the movement produced by said ramp surface; and a locking member biased into engagement with said power unit and said attachment in the assembled position thereof, for preventing relative rotation thereof during operation of said power tool.

Claim 16

A power tool assembly including a power unit and a tool attachment arranged to be coupled thereto in driven relationship comprising complementary sets of bayonet teeth respectively mounted on said power unit and said attachment for insertion of one of said sets into the other of said sets and for relative rotation of said sets into an interlocking position to couple said unit and said attachment; one of said sets including teeth having a ramp surface of increasing height in a direction to cause tight engagement of said unit and said attachment upon said rotation; one of said sets being coupled to one of said power unit and said attachment by a spring means, said spring means being disposed to be displaced from its unstressed configuration by the movement produced by said ramp surface; and a locking member biased into engagement with said power unit and said attachment in the assembled position thereof, for preventing relative rotation thereof during operation of said power tool.

Claim 17

A power tool assembly as claimed in claim 14 wherein said spring means is stretched by said movement.

Claim 18

A power tool assembly including a power unit and a tool attachment arranged to be coupled thereto in driven relationship comprising complementary sets of bayonet teeth respectively mounted on said power unit and said attachment for insertion of one of said sets into the other of said sets and for relative rotation of said sets into an interlocking position to couple said unit and said attachment; one of said sets including teeth having a ramp surface of increasing height in a direction to cause tight engagement of said unit and said attachment upon said rotation; a locking member biased into engagement with said power unit and said attachment in the assembled position thereof, for preventing relative rotation thereof during operation of said power tool.

Claim 19

A power tool assembly including a power unit and a tool attachment arranged to be coupled thereto in driven relationship comprising complementary sets of bayonet teeth respectively mounted on said power unit and said attachment for insertion of one of said sets into the other of said sets and for relative rotation of said sets into an interlocking position to couple said unit and said attachment; one of said sets including teeth having a ramp surface of increasing height in a direction to cause tight engagement of said unit and said attachment upon said rotation; a locking member biased into engagement with said power unit and said attachment in the assembled position thereof, for preventing relative rotation thereof during operation of said power tool.

Claim 20

A power tool assembly including a power unit and a tool attachment arranged to be coupled thereto in driven relationship comprising a coupling member rotationally fixed to and axially movable on one of said power unit and said tool attachment; spring means axially biasing said coupling member toward said one of said power unit and said tool attachment; complementary sets of bayonet teeth respectively mounted on said coupling member and the other of said power unit and said tool attachment for insertion of one of said sets into the other of said sets and for relative rotation of said sets into an interlocking position to couple said unit and said attachment; one of said sets including teeth having a ramp surface of increasing height in a direction to cause tight engagement of said unit and said attachment upon said rotation.

Claim 21

A power tool assembly including a power unit and a tool attachment arranged to be coupled thereto in driven relationship comprising a coupling member rotationally fixed to and axially movable on one of said power unit and said tool attachment; spring means axially biasing said coupling member toward said one of said power unit and said tool attachment; complementary sets of bayonet teeth respectively mounted on said coupling member and the other of said power unit and said tool attachment for insertion of one of said sets into the other of said sets and for relative rotation of said sets into an interlocking position to couple said unit and said attachment; one of said sets including teeth having a ramp surface of increasing height in a direction to cause tight engagement of said unit and said attachment upon said rotation.