Patent ID: 11879298
Assignee: REFLEX INSTRUMENTS ASIA PACIFIC PTY LTD
Field: Civil engineering (Other fields)
Classification: CPC E | IPC E

Claim 15:
16. A drive sub for a drilling assembly, the drive sub comprising
a tubular body configured to receive and releasably engage a tool, the body having an inner face and an outer face;
a castellated edge provided at an operative downhole end of the body, the castellated edge defining a plurality of lugs separated from each other by intervening slots; and
a channel provided in each of the lugs, the channel at least partially traversing the lugs and leading from an inlet opening on the castellated edge to an outlet opening on the outer face,
wherein each channel is open to the outer face along a full extent of the channel and the channel extends at its downhole end from substantially near to the inner face and leads at its uphole end onto the outer face of the body.