Patent Application
20130014996
The present disclosure relates to augers for drilling holes, and in particular to braking apparatus and methods for a powered auger.
Augers are used to drill holes, such as holes in the earth for setting posts. A typical auger has one or more boring blades at the lower end of an upright drive shank and a spiral auger blade (or flighting) extending from the boring blades up a lower portion of the drive shank. The drive shank is rotated to turn the blades to bore into the earth. Some augers are powered, such that the drive shank is rotated by an electric motor or fuel-powered engine.
In a powered auger, the motor/engine (or power unit) is coupled to a transmission, which transfers power from the engine to rotate the blades of the auger. The motor/engine and transmission form a powerhead. A drive shank of the auger may be coupled to a drive shaft of the transmission. A clutch of the transmission, such as a spring or centrifugal clutch, may provide a releasable coupling between the motor/engine and the drive shaft. For example, a clutch drum of the clutch may be coupled to the drive shaft and a spring-loaded rotating disk of the clutch may be coupled to the motor/engine. Increasing rotation of the rotating disk, such as when the rotations per minute (RPMs) of the motor/engine increase, may cause the rotating disk to engage the clutch drum and turn the drive shaft, which rotates the auger bit and/or blade.
The releasable coupling of the motor/engine and the drive shaft by the clutch typically allows the drive shaft (and the drive shank and/or auger bit) to rotate independently from the motor/engine in both the clockwise and counterclockwise direction. Also, typically, powered augers are not equipped to reverse direction. For example, the transmission does not include a reverse gear or setting. Rotation of the drive shaft independent from the motor/engine can be problematic in instances when the auger blade becomes buried by debris in the hole that is being drilled by the auger.
The present disclosure is directed to embodiments of methods and apparatus for braking an auger to limit or prevent rotation of the auger independent from rotation of the motor/engine.
As can be appreciated augers can also be used to drill holes for a variety of purposes besides drilling holes in the earth. For example, an auger can be used to drill holes in or through ice, such as for ice fishing, or other situations where a narrow hole is advantageous. A typical auger hole is four to eighteen inches in diameter.
The present disclosure is directed to apparatus and methods for braking (limiting or preventing rotation of) an auger. The braking device, when activated, may limit or prevent rotation of the flighting of the auger with respect to the motor/engine.
Additional aspects and advantages will be apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings.
Embodiments of the present disclosure may be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. It will be readily understood that the components of the present disclosure, as generally described and illustrated in the drawings herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the apparatus is not intended to limit the scope of the disclosure, but is merely representative of possible embodiments of the disclosure. In addition, the steps of a method do not necessarily need to be executed in any specific order, or even sequentially, nor need the steps be executed only once, unless otherwise specified. In some cases, well-known structures, materials, or operations are not shown or described in detail.
The bit 102 comprises a central bit shank 112 to drive one or more boring blades 114. The bit shank 112 is coaxial with the drive axis 110. The boring blades 114 are positioned and fixedly secured at or near a distal (lower) end of the bit shank 112. A borer tip 116 may also be positioned at the distal end of the bit shank and may be configured to bore a pilot (or starter) hole to guide a direction and/or position of the bit 102. A spiral auger blade 118 or flighting may be coaxially mounted around the bit shank 112, extending in a spiral from the boring blades 114 upward along the drive axis 110.
The bit 102, and correspondingly the bit shank 112, the boring blades 114, the borer tip 116, and the spiral auger blade 118, are configured to rotate around the drive axis 110 when the powered auger 100 is in operation. The proximal (upper) end of the bit shank 112 is configured to couple concentrically to the drive shaft 108, in alignment with the drive axis 110. As the bit shank 112 is rotated about the drive axis 110, the boring blades 114 and auger blade 118 also rotate around the drive axis 110. If the boring blades 114 are pressed against a surface (e.g., the ground, ice, etc.) and rotated in the drilling direction, the boring blades 114 may gradually bore a hole in the surface in a direction distally along the drive axis 110. The auger blade 118 is configured to lift shavings or debris away from the boring blades 114, proximally along the drive axis 110, and out of the hole being cut.
In another embodiment, the bit shank 112 and the drive shaft 108 may be integrated and/or comprise the same component. In the present embodiment, the bit 102 can be removed from the drive shaft 108 for easy replacement, repair, sharpening, etc. However, this is feature is optional and the blades 114, 118 can be mounted to a single, unitary shaft extending from the transmission assembly 106.
A user of the powered auger 100 typically grasps handles 105 that are fixed relative to the power unit 104 and activates the power unit 104 to drill a hole. The user can grasp the handles 105 and use them to guide the boring blades 114 and auger blade 118 and provide a downward force down the drive axis 110 to drill the hole. The handles 105 are typically secured to and fixed relative to a housing of the power unit 104 and/or a housing of the transmission assembly 106.
In some circumstances during drilling, the boring blades 114 and auger blade 118 may become buried in debris, potentially below the surface of, for example, the earth or the ice. When the auger blade 118 becomes buried, the power unit 104 may be incapable of generating sufficient torque to rotate the boring blades 114 and auger blade 118. The bit 102 may become jammed or otherwise stop boring the hole.
Removing a jammed auger from a hole can be very difficult. One solution to this problem is simply reversing the direction of rotation of the auger blade 118 (a direction opposite the drilling direction), which unscrews the auger blade 118 out of the hole. However, generally powered augers do not include a reverse gear or function. Integrating a reverse gear or function into the transmission assembly 106 of a powered auger may be unduly or prohibitively expensive and/or exceed size or space constraints on the transmission assembly. Rotating the auger blade 118 in a direction opposite the drilling direction is also typically not possible due to the transmission assembly 106 releasably coupling the power unit 104 and the drive shaft 108, which allows the drive shaft 108 (and in turn the bit shank 112 and/or auger blade 118) to rotate freely, independent of the power unit 104, in both the clockwise and counterclockwise direction.
In the embodiments of the present disclosure, a braking device 120 is provided to secure the transmission assembly 106 and/or the drive shaft 108 relative to the power unit 104 and/or the handles 105. The braking device 120 may be integrated into the power unit 104, as illustrated. In the present embodiment, the braking device 120 may be integrated into the power unit 104 via the engine fan housing. The braking device 120 may be configured to restrict or even prevent rotation of the drive shaft 108 relative to the power unit 104. Accordingly, a user can activate the braking device 120 and then twist the handles to rotate the auger blade 118 in a direction opposite the drilling direction and thereby remove the auger from the hole.
In the present embodiment, activation of the band 302 may include tightening of the band to reduce a diameter of the loop of the band 302. The band 302 is configured in a circular or loop arrangement having a diameter D that is larger than a clutch drum of the transmission assembly, as shown in
The brake activation assembly 304 may include a shaft 306, a connector 308, a biasing element 312, a mount 314, mounting hardware 316, 318, and an actuator 320. The shaft 306 may have an elongate cylindrical shape having a distal end 330 and a proximal end 332. The connector 308 may be positioned at the distal end 330 of the shaft 306 and configured to secure the free end 303 of the band 302 to the shaft 306. The free end 303 of the band 302 may include and opening 309 or hole configure to receive a pin 310 of the connector 308. In the illustrated embodiment, the free end 303 of the band 302 is received into a slot 307 of the connector 308 and the pin 310 passes through a hole in the connector on a first side of the slot 307, through the opening 309 of the free end 303 of the band 302, and through a hole in the connector on a second side of the slot 307. In this manner, the pin 310 secures the free end 303 of the band 302 to the shaft 306. Accordingly, adjustment of the position of the shaft 306 relative to the fixed end 301 of the band 302 increases or decreases the diameter D of the band 302.
The proximal end 332 of the shaft 306 is configured to couple to actuator 320. The shaft 306 extends into and/or through an opening 324 in the mount 314 to couple to the actuator 320. The actuator 320 in turn is threaded. Accordingly, activation of the actuator 320 can move the position of the shaft 306 relative to the fixed end 301 of the band 302, thereby increasing or decreasing the diameter D of the band 302. In the illustrated embodiment, the proximal end 332 of the shaft 306 is threaded and the actuator 320 is threaded with mating threads, such that rotation of the actuator 320 about a longitudinal axis of the shaft 306 results in linear (longitudinal) displacement of the shaft 306 relative to the actuator 320. More specifically, in the illustrated embodiment, the actuator 320 may define a threaded opening 334 at a distal end to receive mating threads 340 at the proximal end 332 of the shaft 306. Rotation of the actuator 320 screws the shaft 306 into the actuator 320 and displaces the shaft 306 linearly in the direction of the actuator 320. Displacement of the shaft 306 in the direction of the actuator 320 decreases the diameter D of the band 302, thereby transitioning toward an activated configuration in which the band engages a component of the transmission assembly 106.
The biasing element 312 is received into the threaded opening 334 and may abut against a floor (or distal end) of the threaded opening 334 and a proximal end 332 of the shaft 306. The biasing element 312 may serve to bias the actuator 320 and the shaft 306 apart. Thus, the biasing element 312 may bias the braking device 120 toward an unengaged or deactivated configuration, in which the braking device 120 is not engaging the drive shaft 108 and rotation of the drive shaft 108 relative to the power head 104 is unrestricted. Biasing the braking device 120 toward an unengaged configuration may be particularly useful during operation when vibrations can act to engage braking device 120, inadvertently. In the illustrated embodiment, the biasing element 312 may comprise a spring.
A spacer 322 may facilitate securement of the actuator 320 relative to the mount 314, such that displacement of the shaft 306 relative to the actuator 320, resulting from rotation of the actuator 320, increases or decreases the diameter D of the band and disengages or engages the band 302 with a component of the transmission assembly 106. The mount 314 may include mounting holes 317, 319 to receive mounting hardware 316, 318 that may secure the mount 314 relative to a housing of the transmission assembly 106 and/or power unit 104.
As will be appreciated by an ordinarily skilled artisan, in other embodiments, the shaft 306 may include an opening having femail threads that mate with male threads of the actuator 320. In still other embodiments, actuation of the actuator 320 may be accomplished by linear movement rather than by rotation of the actuator (e.g., similar to pushing a button or pulling a knob). Any appropriate actuator mechanism may be utilized.
Rotation of the actuator 320 can move the position of the shaft 306 linearly. Linear movement of the shaft 306 in turn increases or decreases the diameter D of the band 302. The biasing element 312 is positioned in the mount 314 and is configured to abut a shoulder 402 in the opening 324 through the mount 314 and configured to abut the connector 308 at the distal end of the shaft 306. The biasing element 312 may serve to bias the shaft 306 away from the actuator 320, thereby biasing the braking device 120 toward an unengaged configuration, such that rotation of the drive shaft 108 relative to the power head 104 is unrestricted by the braking device 120. In other embodiments, the biasing element 312 may bias the braking device 120 toward an engaged configuration, such that rotation of the drive shaft 108 relative to the power head 104 is restricted by the braking device 120.
Referring collectively to
The braking device 120 of the present embodiment, when activated, engages the clutch drum 502 to restrict rotational movement of the clutch drum 502 relative to the housing of the transmission assembly 106 and/or the power head 107. The mount 314 of the braking device 120 may be secured to a shroud 506 of the housing of the power unit 104, as shown. In another embodiment, the mount may be secured to a component of the housing of the transmission assembly 106. In the present embodiment, the housing of the transmission assembly 106 is secured to and/or fixed relative to the power unit 104. Thus, securement relative to the transmission assembly 106 results in securement relative to the power head 104. As described above, the handles 105 (see
As previously described, the braking device 120 includes a band 302 and a brake activation assembly 304. When the braking device 120 is activated, the band 302 may include an elongate strip of material, such as metal, with a pair of ends and arranged in a loop around the clutch drum 502. A first end 301 may be configured as a fixed end and a second end 303 may be configured as a free end. When the braking device 120 is activated, the loop of the band 302 reduces in diameter, thereby engaging the clutch drum 502. In the illustrated embodiment, the free end 303 moves linearly toward the actuator, while the fixed end does not move, thereby shortening the loop of the band 302 and causing the band 302 to engage the clutch drum 502. Engagement of the clutch drum 502 by the band 302 results in releasable securement of the clutch drum 502, which restricts and/or prevents rotational movement of the clutch drum 502 (and the drive shaft 108 and the bit 102) with respect to the braking device 120, the housing of the transmission assembly 106, and the power unit 104.
The brake activation assembly 304 may include a shaft 306 (see
In another embodiment, the braking device 120 may include a pin or fork to engage the clutch drum. The pin or fork may be utilized in place of the band. The pin or fork may be coupled to a brake activation assembly, which may be activated by a user to laterally displace the pin or the fork relative to the clutch drum. Lateral displacement of the pin or fork may result in the pin or fork engaging one or more holes in the clutch drum to restrict or prevent rotation of the clutch drum relative to the power unit.
It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. The scope of the present invention should, therefore, be determined only by the following claims.
