Tap holder
AssigneeS & L Maskin AB
InventorDag Stenmark
Life of this patent
Estimating the term…
Abstract
A tap holder e.g. for threading taps, has a drive body (1) intended for connecting to the chuck of a drive motor. The driving power is transferred by a torque-limiting device (2, 9, 11) to a clamping body (8) intended to clamp the shank (12) of the threading tap. By the clamping body having outer (6) and inner (5) jaws with an intermediate elastic member (7), tool shanks of different dimensions may be accommodated by the clamping body.
Claims8
A tap holder including a drive body (1) intended to be fixed into a chuck on a rotational motor and adapted for transmitting the motor driving power to the shank (12) of the tool which the motor is to drive, the drive body (1) being connected to a clamping body (8) for retention of the shaft, said tap holder being characterized in that the part of the clamping body (8) surrounding the shank (12) has a forward and a rear annular conical surface (14 and 15) with an intermediate abutment (16), the forward conical surface (14) being adapted for coaction with forward clamping jaws (6) for clamping against the usually circular intermediate part of the shaft, and the rear conical surface (15) being adapted to coact with rear jaws (5) for clamping against the usually square top portion of the shank, said forward and rear jaws (6, 5) being separated by an intermediate flexible member (7).
A tap holder involving an overload clutch including a drive body (1) intended for mounting in a chuck on a rotational motor and adapted to transmit the motor driving power to the shank (12) on the tool the motor is to drive, the drive body (1) being coupled to a clamping body (8) for retaining the shaft, and the power transmission from the drive body (1) being arranged to take place via a driving dog (2), which is in engagement with a spring biased (via 10) lock ring (9), balls (11) in a groove (19) on the surface of the drive body (1) being forced out of the groove when resistance to turning of the shank (12) during operation exceeds a predetermined torque and causes the lock ring (9) to leave its engagement with the driving dog (2) so that the power transmission is interrupted, characterized in that said predetermined torque is automatically adjustable when the shank (12) is gripped by the clamping body (8) in relation to the shank diameter and its square top portion by the clamping body (8) having a conical surfaces (14,15) for forward and rear clamping jaws (6,5) having a flexible member (7) therebetween, movement of the jaws (6,5) being coupled through the flexible member (7) to adjust the spring bias (via 10) due to the diameter and square dimensions of the shank (12) to a force answering thereto and corresponding to the predetermined torque required for a particular size of the shank.
Dependencies are inferred from the claim text.