Patent ID: 8327953

Claim:
A downhole drilling tool for drilling in a drilling direction in a downhole valve or a formation downhole, comprising: a drilling head having at least one drill bit and being in connection with a first portion of the tool, a driving unit for driving the drilling head and the first portion forward in a longitudinal movement while drilling, the driving unit being in connection with a second portion of the tool, and a fixating device in connection with the second portion for abutment of the tool against the downhole valve or the formation downhole and for fixation of the tool when drilling, wherein the tool further comprises a feed control inside the tool for controlling the longitudinal movement of the drilling head in the downhole valve or the formation downhole by controlling a movement of the first portion in relation to the second portion of the tool, wherein the feed control comprises: the second portion fixedly provided within the tool wherein the first and second portion together form a first fluid chamber, a second fluid chamber in fluid connection with the first fluid chamber, and a fluid control means for controlling a rate of fluid passing from one chamber to the other for controlling the longitudinal movement of the drilling head in relation to the drilling tool, wherein the fixating device is situated in front of the tool in the drilling direction for abutment of the tool against the downhole valve in front of the tool or the formation downhole in front of the tool.