Title: Downhole weight control device for impact rock drilling tool

Abstract: A downhole weight control device is described for connecting to the upper end of a downhole, pneumatically-operated, impact rock drilling tool for applying a downward force on the tool sufficient to maintain the drill bit in the closed working position. The weight control device has a piston member that has an effective area related to the surface area of the hammer piston in the drilling tool to effectively counterbalance an upward force of the tool tending to lift the tool. The control device also prevents exerting excessive weight on the drill bit. The control device has means for automatically decreasing the working pressure should the drill string be fed for a period of time at a rate greater than the penetration rate of the tool.

Do you think this is a good invention? Vote now:

Votes so far: For:(0) Against:(0)
Other info:

Inventors: Adcock, Gerald L. (Lewiston, ID, US)

Application Number: 864780
Filing Date: 1977-12-27
Publication_date: 1980-07-15
Assignee:
Primary Class(es): 175/26 175/94, 175/321
Other Classes:
US Patent Ref:

2684835	Jul, 1954	Moore	175/321.
3198264	Aug, 1965	Oelke et al.	173/78.
3463252	Aug, 1969	Miller et al.	175/321.
3815692	Jun, 1974	Varley	175/321.
3858188	Dec, 1974	Vasiliev et al.	175/321.

Other Refs:
Primary Examiner: Pate, III, William F.
Assistant Examiner:
Attorney: Wells, St. John & Roberts