Chuck for driving tap or like rotary tool

• US 4,088,418 A
• Filed: 04/28/1977
• Issued: 05/09/1978
• Est. Priority Date: 04/30/1976
• Status: Expired due to Term

• Current Assignee: Morris Tooling Limited
• Original Assignee: B O Morris Limited
• Inventors: Dann, Robert S.
• Primary Examiner(s): Weidenfeld, Gil
• Application Number:
  US05/791,788
• Time in Patent Office: 376 Days
• Field of Search: 408/139, 10/135 R, 10/89 F, 64/29
• US Class Current: 408/139
• CPC Class Codes: B23B 31/1071 Retention by balls balls acting as jaws B23B31/22
• CPC Class Codes: B23B 31/38 with overload clutches B23B31/086 takes precedence
• CPC Class Codes: F16D 7/046 with a plurality of axially moving parts
• CPC Class Codes: F16D 7/08 moving axially between engagement and disengagement
• CPC Class Codes: Y10T 408/70 Tool or tool-support with torque-applying clutch

Abstract

A tap-driving chuck, having a driven shaft and a driving sleeve spaced co-axially from the shaft to provide an annular space closed at one end by an annular flange extending from the sleeve. Several circumferentially-spaced balls are positioned in the annular space and are urged by a spring into shallow depressions formed in the annular flange. The balls are each located in slots in a circumferential edge of a flange on the shaft. A driving torque applied to the sleeve is transmitted by the balls to the shaft only while the balls are urged by the spring into the depressions. The balls are lifted against the spring force out of the depressions when the torque being transmitted reaches an upper limiting value, the sleeve then turning idly past the balls.

Claims

1. A chuck for driving a tap or like rotary tool comprising a rotatable shaft having socket-defining means therein co-axial with the axis of rotation of the shaft, the socket-defining means being shaped to impart positive rotational drive to the tap or other tool and to retain the latter in the chuck during a cutting operation, a driving sleeve mounted co-axially on the shaft and spaced radially therefrom to leave an annular space between the shaft and the sleeve, a first flange extending from one of the sleeve and the shaft closing one end of the annular space, at least one drive-transmitting member positioned in the annular space, spring means acting to urge said drive-transmitting member into a shallow depression formed in said first flange, a second flange on the other of the sleeve and the shaft and having an open-ended slot in the circumferential edge of said second flange, said slot having said drive-transmitting member positioned therein, said slot having a side wall extending in a direction radially of said second flange, and forming of a driving surface against which said drive-transmitting member abuts on rotation of said sleeve, whereby a driving torque applied to said sleeve will be transmitted by said drive-transmitting member to said shaft while said drive-transmitting member is urged by said spring means into said shallow depression in said first flange, the force of said spring means permitting said drive-transmitting member to be lifted against the spring force out of said shallow depression in said first flange when the torque being transmitted between said sleeve and said shaft exceeds a limiting value and thereby to interrupt the transmission of torque between said sleeve and said shaft.

2. A chuck as claimed in claim 1 in which said other sid wall of said slot is sloped away from said radial side wall, whereby on turning said sleeve in the reverse direction, said drive-transmitting member will tend to wedge between said other side wall of said slot and said one of the sleeve and the shaft and hence effect driving of said shaft in said reverse direction, whereby the tool will be driven away from a workpiece.

3. A chuck as claimed in claim 1 in which said drive-transmitting member is a cylindrical pin having a part-spherical end engageable with said shallow depression in said first flange.

4. A chuck as claimed in claim 1 in which said drive-transmitting member is a ball and said slot in said second flange has a side wall parallel to a radial centre-line through said slot and also to the longitudinal axis of said second flange, whereby when said sleeve is rotated, said side wall of said slot will engage said ball and hence drive said shaft as long as said spring means holds said ball in said shallow depression in said first flange, but when the torque being transmitted between said sleeve and said shaft reaches a predetermined value, said ball will ride out of said shallow depression against the force of said spring means, thereby interrupting the transmission of torque between said sleeve and said shaft.

5. A chuck as claimed in claim 4 in which said other side of said slot in said second flange is parallel to the radial centre-line through said slot and is also inclined to a plane parallel to the longitudinal axis of said second flange, whereby on turning said sleeve in the reverse direction, said ball will be engaged by said other side wall of said slot and will be held by the wedging effect of the inclined side wall in said shallow depression, thereby positively transmitting torque between said sleeve and said shaft and hence to effect driving of said shaft in said reverse direction, whereby said tool will be driven away from a workpiece.

6. A chuck as claimed in claim 1 in which there is a plurality of drive-transmitting members circumferentially-spaced apart in said annular space at substantially equal intervals and the same number of shallow depressions in said first flange and the same member of slots in said second flange as there are drive-transmitting members.