Patent Application
20160258221
This invention relates generally to drilling devices and, more particularly, to an expandable diameter drill bit having a torsion spring for biasing one or more blades outwardly such that a hole being drilled is enlarged.
Rotary drilling devices are used to bore a generally cylindrical hole into the ground to a depth at which a fluid may be extracted, such as water, oil, natural gas, or the like. Sometimes an existing well needs to be re-drilled, cleaned out, or the diameter expanded. A rotary drill may include one or more blades that scrape or dig into the ground surface as the drill rotates. The blades often wear out, break, or otherwise fail and must be replaced, especially when operated at high speed. Another problem with drilling devices is that a drill bit having one diameter may be used and then replaced with a drill bit having a larger diameter in order to increase the diameter of the well.
Although existing rotary drilling devices are presumably effective to drill subsurface wells, they are less effective in operating to increase the diameter of the hole. For instance, some expanding diameter drill bits urge their blades outwardly by centrifugal force and, as a result, require high speed rotation which may not be possible in some subsurface conditions or if debris is building up too quickly within a hole.
Therefore, it would be desirable to have an expandable diameter drill bit having one or more blades that are automatically biased outwardly by respective torsion springs. Further, it would be desirable to have an expandable diameter drill bit having a construction that is less susceptible to blade breakage and more effective in cutting through rock.
An expandable diameter drill bit according to the present invention includes a cutting blade having a receiving end and a contacting end, the receiving end having a pivot shaft and the contacting end having a tip. A drill bit includes a drill head body having an upper attachment portion and a lower body portion, the lower body portion defining a blade opening for receiving the receiving end of the cutting blade and a bolt receiving hole on each of two opposing sides transverse the blade opening. The drill bit includes a torsion spring having a helical coil, a first blade leg, and a second body leg. The blade bolt passes through the bolt receiving holes and the pivot shaft and is secured into position with a blade bolt set screw. The first blade leg is coupled to the cutting blade with a spring retainer bolt, the second body leg is coupled to the drill head body, and the torsion spring biases the blade outwardly from the drill head body.
The drill bit 10 may be inserted into a hole with the purpose of expanding the hole diameter as it is lowered therein. The drill bit is spun around such that the blades cut away at the edges of the hole. As the diameter of the hole becomes larger, the oppositely biased torsion springs force the blades outward, thus causing the hole to become even larger.
Therefore, a general object of this invention is to provide an expandable diameter drill bit for efficiently drilling a well beneath the surface of the Earth.
Another object of this invention is to provide an expandable diameter drill bit, as aforesaid, in which a pair of blades is pivotally movable between a retracted configuration not extending outwardly from a drill body and an extended configuration extending outwardly from the drill body.
Still another object of this invention is to provide an expandable diameter drill bit, as aforesaid, in which each cutting blade is naturally biased toward the extended configuration by a respective torsion spring.
Yet another object of this invention is to provide an expandable diameter drill bit, as aforesaid, in which each cutting blade may be coated with or include materials that cut more effectively through subsurface compositions and debris.
A further object of this invention is to provide an expandable diameter drill bit, as aforesaid, that cuts more effectively through subsurface compositions and debris.
A still further object of this invention is to provide an expandable diameter drill bit, as aforesaid, in which each cutting blade includes serrated teeth.
Other objects and advantages of the present invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, embodiments of this invention.
An expandable diameter drill bit and method of use will now be described with reference to
With reference to
An outside edge 107 of the upper threaded portion 105 may be inserted into, for example, a drill string (not shown). The threaded portion 105 may be configured such that when the drill bit 10 is connected to the drill string and in use the drill bit 10 does not become loosened. Other means for ensuring semi-permanent connection to the drill string (or other guiding device) is contemplated within the scope of the present invention. It shall also be understood that drill bits generally have a shortened lifespan due to the conditions under which they are used, and therefore, as will be appreciated by those skilled in the art, it may be preferable that the drill bit 10 is removable from the drill string (or other guiding device) at the end of its life.
The upper threaded portion 105 terminates at an inside edge 109 of a top face of the lower body portion 110. The lower body portion 110 may define blade openings 112 for accepting receiving ends 205 of the blades 200. The blade openings 205 may be separated by a divider 115 for ensuring proper positioning of the blades 200 and to prevent the blades 200 from rubbing against each other during use.
Bolt receiving holes 120 in opposing sides of the drill head lower body portion 110 and though the center of the divider 115 may generally correspond to holes 210 (pivot shafts) in receiving ends 205 of the blades 200. Referring now to
A channel 133 (
The lower body portion 110 may further be equipped with a fluid discharge hole 128. Fluids are often used to reduce friction, provide buoyancy to the drill string, and remove cuttings from the well bore. As the well bore in which the drill is operating is flooded with fluids, the fluid discharge hole 128 may allow for fluids to be discharged away from the drill head body 100.
The blades 200 provide the means by which surface material is displaced to form a hole, and in some particular embodiments, a well bore hole. Each blade 200 may be generally rectangular at the receiving end 205 and culminate at a tip at the surface contacting end 215. The tip may have a rounded configuration as shown in the drawings although a pointed tip may also be used in other embodiments not shown). An upper corner 212 of the blade at the receiving end 205 may be rounded to facilitate rotation of the blade 200 about the blade bolt 130 while situated inside of the blade openings 112.
Outer edges 214 of the blades may be serrated to increase the performance of the blades. Serrated edges may be superior to plain edges because serrated edges tend to grab and cut the material as the blades come into contact with the surface. The blades may be made of any material strong enough to withstand the high forces exerted on the blades as they rotate and cut away at the surface. Exemplary materials include steel, steel alloys, tungsten carbide, cubic boron nitride, et cetera.
In addition to the blades themselves, the edges may be coated in a material exhibiting superior hardness properties thereby increasing the effectiveness of the blades and the life of the drill. In some embodiments, the edges 214 may additionally or alternately be equipped to receive an insert 220, such as that shown in
It should be noted that the blades may be any desired length based on the requirements of a particular project (e.g., 20″, 25″, 30″, 35″, 40″, 45″, etc.). Additionally, while the embodiments described herein focus on the use of two opposing blades, additional or fewer blades could be used depending on the particular project.
With reference to
When the springs 300 are in full tension, the blades 200 are in a retracted position as illustrated in
In use, the drill bit 10 is inserted into a hole with the purpose of expanding the hole diameter. The blades 200 may first be in the retracted configuration so as to fit into the hole as described above. The drill bit 10 is spun around such that the blades 200 cut away at the edges of the hole. As the hole becomes larger (i.e. has a larger diameter), the springs 300 force the blades 200 outwardly, thus causing the hole to become even larger.
While many methods of manufacturing the drill head body 100 and blades 200 are contemplated within the scope of the present invention, some exemplary methods include die casting, molding, forging, extruding, machining, et cetera.
Many different arrangements are possible without departing from the spirit and scope of the present invention. Embodiments of the present invention are described herein with the intent to be illustrative rather than restrictive. Alternative embodiments will become apparent to those skilled in the art that do not depart from its scope. A skilled artisan may develop alternative means of implementing the disclosed improvements without departing from the scope of the present invention. Further, it will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations and are contemplated within the scope of the claims. The description should not be restricted to the specific described embodiments.
