Earth-boring tools including retractable pads, cartridges including retractable pads for such tools, and related methods
View Patent ↗An earth-boring tool may comprise at least one cavity formed in a face thereof. At least one retractable pad residing in the at least one cavity may be coupled to a piston located at least partially within the at least one cavity. Additionally, a valve may be positioned within the earth-boring tool and configured to regulate flow of an incompressible fluid in contact with the piston through an opening of a reservoir. A cartridge may comprise a barrel wall defining a first bore, and a piston comprising at least one retractable pad positioned at least partially within the first bore. The barrel wall and the piston may define a first reservoir within the first bore, and a valve may be positioned and configured to regulate flow through an opening to the first reservoir. Related methods and devices are also disclosed.
1. A cartridge for an earth-boring tool, the cartridge comprising:
a barrel wall defining a first bore;
a piston comprising at least one retractable pad positioned at least partially within the first bore;
a first reservoir within the first bore adjacent the piston;
an opening to the first reservoir;
a valve positioned and configured to regulate fluid flow through the opening; and
another barrel wall defining a second bore and having a second reservoir therein positioned for fluid communication with the first reservoir through the valve, wherein the valve is positioned between the first reservoir and the second reservoir.
2. The cartridge of claim 1 , further comprising:
a second piston positioned within the second bore adjacent the second fluid reservoir.
3. The cartridge of claim 1 , further comprising:
a diaphragm enclosing at least a portion of the second bore adjacent the second fluid reservoir.
4. An earth-boring drill bit, comprising:
a plurality of cavities in a face of the earth-boring drill bit;
a retractable pad coupled to a first piston located at least partially within each cavity of the plurality of cavities;
a substantially incompressible fluid in contact with the first piston and contained within a first reservoir;
a plurality of bores in fluid communication with the plurality of cavities and in contact with the substantially incompressible fluid;
a second piston located at least partially within a second reservoir in each bore of the plurality of bores;
a valve positioned between the first reservoir and second reservoir in each bore of the plurality of bores, the valve configured to selectively flow fluid between the first reservoir and the second reservoir; and
a swash plate operably coupled to each second piston.
5. A method of operating an earth-boring tool, the method comprising:
drilling a borehole with an earth-boring tool with at least one retractable pad protruding from a face of the earth-boring tool adjacent at least one cutting structure;
opening a valve within the earth-boring tool to release a fluid from a first reservoir positioned beneath the at least one retractable pad and reducing the amount of protrusion of the at least one retractable pad from the face of the earth-boring tool while within the borehole;
further drilling the borehole after reducing the amount of protrusion of the at least one retractable pad from the face of the earth-boring tool;
pressurizing a fluid within the earth-boring tool while positioning the earth-boring tool off bottom;
opening the valve; and
extending the at least one retractable pad.
6. The method of claim 5 , further comprising sensing at least one change in rotational speed of the earth-boring tool and opening the valve in response to the sensed change in rotational speed of the earth-boring tool.
7. The method of claim 5 , further comprising sensing at least one change in weight on the earth-boring tool and opening the valve in response to the sensed change in weight on the earth-boring tool.
8. The method of claim 7 , further comprising, maintaining a rotational speed of the earth-boring tool while sensing the at least one change in weight on the earth-boring tool.
9. The method of claim 8 , wherein maintaining the rotational speed of the earth-boring tool comprises maintaining a rotational speed that is substantially zero rotations per minute.
10. The method of claim 5 , further comprising releasing fluid from the first reservoir into a drilling fluid channel of the earth-boring tool upon opening the valve.
11. The method of claim 5 , further comprising releasing fluid from the first reservoir into a second reservoir upon opening the valve.
12. The method of claim 11 , further comprising moving a second piston within the earth-boring tool in response to releasing the fluid from the first reservoir.
13. The method of claim 12 , further comprising deflecting a diaphragm within the earth-boring tool in response to releasing the fluid from the first reservoir.