Abstract: According to a first aspect of the invention we provide a self-retaining drive shaft assembly for use with a device for tightening and loosening of an industrial fastener having: a drive retainer drive shaft; a drive retainer cap; a drive retainer plunger; and a drive retainer segment assembly. The segment assembly is formed between the drive shaft and the cap. The cap is formed between the segment assembly and the plunger. The segment assembly, the cap and the plunger are formed substantially within the drive shaft. Advantageously the retainer assembly is of unitary construction; requires no loose parts or external implements to engage and secure the drive shaft to a drive head of the device; reduces likelihood of device failure during operation due to improper engagement of the drive shaft; and increases user safety during device operation.

Abstract: According to a first aspect of the invention we provide a self-retaining drive shaft assembly for use with a device for tightening and loosening of an industrial fastener having: a drive retainer drive shaft; a drive retainer cap; a drive retainer plunger; and a drive retainer segment assembly. The segment assembly is formed between the drive shaft and the cap. The cap is formed between the segment assembly and the plunger. The segment assembly, the cap and the plunger are formed substantially within the drive shaft. Advantageously the retainer assembly is of unitary construction; requires no loose parts or external implements to engage and secure the drive shaft to a drive head of the device; reduces likelihood of device failure during operation due to improper engagement of the drive shaft; and increases user safety during device operation.