GB1291146A - Tap chucks - Google Patents

Abstract

1291146 Chucks; tap-holding attachment M MATSUMOTO 15 Sept 1970 44004/70 Headings B3B and B3N A tap-holding chuck comprises a main body A (Fig. 1) and a tap holder B the latter of which comprises a clamping means (Fig. 4) for receiving the shank of a tap 33, a shank 22 received within a sleeve 21 and connected for rotation therewith, the sleeve 21 being in driving engagement with the main body via an arrangement of a clutch including a fixed ring 27 in frictional engagement with a movable ring 29 splined to sleeve 21 and urged axially against fixed ring 27 through an elastomeric ring 31. In operation, if, during rotation of the main body and tap, the load on the tap exceeds a set torque as determined by the frictional force between rings 27, 29 then slippage occurs to interrupt the drive to the tap. The force is adjusted by a ring 30. The axial position of shank 22 in sleeve 21 is adjustable by bolt 24. The shank of the tap is clamped by balls 35 in an axially movable sleeve 32 which is spring- urged to its clamping position. The tap holder B is secured in a hollow shaft 5 of the main body A by balls 17 and a surrounding spring-urged collar 19. Shaft 5 is axially slidable in bore 2 of the main body. Its axial position is determined by springs 12, 13 which normally balance each other; if, during a tapping operation, the feed rate differs from the tapping pitch, axial movement of shaft 5 is possible to compensate for such difference. Driving engagement between the shaft 5 and a body portion 1b is established by balls 6a, 6b.