Retention system for motor grader bits

A tool bit is disclosed. The tool bit includes a working portion at a distal end of the tool bit, a threaded portion at a proximal end of the tool bit, a shank extending along a longitudinal axis of the tool bit between the working portion and the threaded portion, and an anti-rotation receiving hole located on the threaded portion. The anti-rotation receiving hole extends through the threaded portion transverse to the longitudinal axis. The threaded portion of the tool bit is configured to engage with threads of a nut, and the anti-rotation receiving hole is configured to receive a pin inserted through the nut.

TECHNICAL FIELD

The present disclosure generally systems and methods of retaining bits, and more particularly, to a system for securing motor grader bits in an adapter board of a motor grader machine.

BACKGROUND

Work machines, such as motor graders, may have ground engagement members (e.g., wheels or tracks) to drive the machine over the ground. A motor grader may be equipped with a tool, such as a blade, to bear against the ground over which it is driven. In some applications, the grader is equipped with a series of bits instead of a blade to better cut and break up the ground. In such a configuration, the blade is replaced with an adapter board, or mold board, that secures the bits.

Retention of the bits into the moldboard may be performed with applying nuts or snap rings on a back side of the bits. Under operating conditions, vibration of the machine may cause for loosening of the bit retention mechanisms. Further, snap rings may be difficult to install and may become lost during operation. The snap rings may become lost due to material buildup, improper installation, and the like. Without the snap ring for retention, the cutting bit may fall out of the moldboard and be lost.

U.S. Pat. No. 4,883,129A entitled Bit Assembly Utilizing Carbide Insert, provides for a ground engaging bit used in abrasive road grading applications. Due to wear, carbide inserts in the tips often break requiring replacement. The '129 patent provides for a means for retaining the bit assembly that includes a retaining ring located in a groove of a shank on the bit.

While arguably effective for its intended purpose there is still need for improved retention of motor grader tool bits.

SUMMARY

In accordance with one aspect of the present disclosure, a tool bit includes a working portion at a distal end of the tool bit, a threaded portion at a proximal end of the tool bit configured to receive a fastener, and a shank extending along a longitudinal axis of the tool bit between the working portion and the threaded portion. In some such embodiments, the fastener is a nut and the threaded portion comprises threads on an outer surface of the threaded portion, the threads configured to receive a nut. In such an embodiment, the tool bit may further include an anti-rotation receiving hole located on the threaded portion. The anti-rotation receiving hole extends through the threaded portion transverse to the longitudinal axis. The threaded portion of the tool bit is configured to engage with threads of a nut, and the anti-rotation receiving hole is configured to receive a pin inserted through the nut. In another such embodiment, the threaded portion comprises an internally threaded portion configured to receive a retention bolt.

In another aspect of the present disclosure, a system for securing a tool bit includes a tool bit having a working portion at a distal end of the tool bit, a threaded portion at a proximal end of the tool bit, a shank extending along a longitudinal axis of the tool bit between the working portion and the threaded portion, and an anti-rotation receiving hole located on the threaded portion. The securing system further includes a nut configured to engage with the threaded portion of the tool bit and a cotter pin to be inserted through the anti-rotation receiving hole and the nut. In some embodiments, the nut may be a castle nut having a plurality of slots circumferentially disposed about the nut and threads configured to engage with the threaded portion of the tool bit, and a pin. In a secured configuration, the shank of the tool bit is inserted through the bore hole of the adapter board, the threaded portion extends from the bore hole into the clearance region, the threads of the nut are engaged with the threaded portion of the tool bit, the pin is inserted through two opposing slots of the plurality of slots of the nut and the anti-rotation receiving hole, and the tail ends of the pin are deformed around the nut.

In such an embodiment, the system may further include a washer. In such an embodiment, when in the secured configuration, the washer is disposed about the shank of the tool bit between the nut and the leading edge of the adapter board. In another such embodiment, the anti-rotation receiving hole is drilled into the threaded portion. In yet another embodiment, when in a the secured configuration, the nut is hand-tightened to engage the threaded portion of the tool bit. In yet another embodiment of the present disclosure, a tool bit includes a shank extending along a longitudinal axis of the tool bit, the shank having an internally threaded portion configured to receive a retention bolt, and a working portion at a distal end of the tool bit. The working portion of the tool bit includes an anti-rotation segment having a flat side configured to engage an anti-rotation slot of an adapter board. In one such embodiment, the shank of the tool bit may be configured not to extend through a bore hole of the adapter board. When in a secured configuration, a washer is disposed about a bolt, the bolt is threaded into the internally threaded portion of the tool bit, and the bolt is torqued into the internally threaded portion with a wrench.

These and other aspects and features of the present disclosure will be more readily understood when read in conjunction with the accompanying drawings.

DETAILED DESCRIPTION

Referring now to the drawings, and with specific reference toFIG. 1, a tool bit is disclosed. In particular,FIG. 1depicts the side view100of the tool bit102. A working portion104is located at a distal end106of the tool bit102. A threaded portion108is located at a proximal end110of the tool bit102. A shank112, and the threaded portion108, extend along a longitudinal axis116. The working portion104extends along the working-portion axis126. In some embodiments, the working portion104does not extend along the same axis as the longitudinal axis, such as depicted in the view100of the tool bit102. Here, the working portion104is angled down and to the right along the working-portion axis126as compared to the longitudinal axis116. As such, the longitudinal axis116and the working-portion axis126intersect. The difference in angle between the longitudinal axis116and the working-portion axis126provide for proper engagement of the working portion10with a ground surface (not depicted). At the working portion104, a cutting surface122may be have a planar shape and be realized by a carbide tip, a tungsten carbide tip, or the like. While the cutting surface122may be designed to be durable, it may be desirable for a tool bit securing system to provide for replacement of individual tool bits on a machine due to wear experienced during operations.

At the proximal end110, the tool bit102includes a threaded portion108. The threaded portion108is configured to receive a fastener. In some embodiments, such as those depicted inFIG. 1, the threaded portion108includes threads on an outer surface of the threaded portion (e.g., is externally threaded). In such embodiments, the fastener may be realized by a nut, a castle nut, or the like. In other embodiments, discussed in conjunction withFIGS. 8 and 9, the threaded portion108may be realized by an internally threaded portion808and the fastener may be realized by a retention bolt804. Returning to the discussion ofFIG. 1, the threaded portion108includes an anti-rotation receiving hole114. In some embodiments, the anti-rotation receiving hole114is drilled into the threaded portion108and is transverse to the longitudinal axis116. The location of the anti-rotation receiving hole114may be placed at a location along the longitudinal axis116to permit engagement with a pin302that is disposed between slots206of a nut202.

At the end of the shank112away from the proximal end110, the tool bit102transitions to a shoulder128that includes a larger cross-sectional area than that of the shank112. The shoulder128is configured to abut against an adapter plate in response to a force applied along the longitudinal axis116(e.g., by a nut202engaging with the threaded portion108or by the working portion104being engaged with the ground surface).

In some embodiments, the tool bit102includes an anti-rotation segment118. As depicted in the view100, the anti-rotation segment118may be realized by a flat side120. Here, the tops and the bottoms of the tool bit may be realized as having rounded surfaces130. However, the flat side120is configured to abut against an anti-rotation slot602on a leading edge514of an adapter board506. The flat-surface to flat-surface engagement between the flat side120and the anti-rotation slot602prevent the tool bit102from rotating about its longitudinal axis116.

In some embodiments, the anti-rotation segment118includes two parallel flat surfaces on opposing sides of the tool bit. Each of the flat surfaces may engage with the anti-rotation slot602to prevent rotation of the tool bit102when secured into the adapter board506. In other embodiments, the anti-rotation segment118may include keying to ensure that the tool bit102is installed in the correct orientation when secured to the adapter board506. For example, the tool bit102may have an anti-rotation segment118having a flat surface120on a first side of the tool bit102and a rounded portion130on the opposite side of the tool bit. The anti-rotation slot602may be complementarily designed to allow full insertion of the tool bit102into the adapter board506only when the tool bit102is properly oriented.

FIG. 2is a perspective view of a nut, in accordance with an embodiment of the present disclosure. In particular,FIG. 2depicts the perspective view200of the nut202. In some embodiments, the nut202is a castle nut having the features depicted in the view200. The nut202includes threads204located about an inner circumference of the nut202. The threads204are configured to engage with the threaded portion108of the tool bit102. In such an embodiment, the nut202may have the same diameter opening as the threaded portion108and be machined with threads of a pitch that complement the threads of the threaded portion108. The nut202further includes a plurality of slots206disposed between a plurality of upright members208. The upright members208are positioned such that the slots206are configured to receive a pin302being inserted through the anti-rotation receiving hole114.

FIG. 3is a side view of a pin, in accordance with an embodiment of the present disclosure. In particular,FIG. 3is a perspective view300of the pin302. The pin302may be adapted to be inserted through the anti-rotation receiving hole114and a nut202. The pin302includes an eyelet304on the right portion of the view300and two tail ends306on the left side of the view300that are able to be deformed. The dimension across the eyelet (e.g., the eyelet diameter) may be selected to be larger than a diameter of the anti-rotation receiving hole to prevent the pin302from being pulled through the anti-rotation receiving hole114.

In some embodiments, the pin302may be realized as a cotter pin. In other such embodiments, the pin302may be realized by a piece of lock wire inserted through the anti-rotation receiving hole114, with ends of the lock wire twisted together to secure the lock wire into the anti-rotation receiving hole114.

FIG. 4is a perspective view of the first tool bit engaged with a nut, in accordance with an embodiment of the present disclosure. In particular,FIG. 4depicts the perspective view400that includes the tool bit102with a washer406disposed about the threaded portion108, a nut202engaged with the threaded portion108, and a pin302inserted through both the slots206of the nut202and the anti-rotation receiving hole114. As depicted inFIG. 4, the anti-rotation receiving hole114extends along the axis404. The tool bit102also includes the cutting surface122having a working edge124. The working edge124extends along the axis402. In some embodiments, the axis402of the working edge124is parallel to the axis404of the anti-rotation receiving hole114. As such, when installing a pin302into the anti-rotation receiving hole114(e.g., in a tool bit securing system), the orientation of the anti-rotation receiving hole114may permit increased access to the anti-rotation receiving hole114in relation to other obstructions (e.g., adapter plate, mold board). In other embodiments, the anti-rotation receiving hole114is drilled into the threaded portion108of the tool bit102such that its axis404is not parallel to the axis402of the working edge124. Such alternate orientations may be selected based on expected obstructions adjacent to the clearance region510.

FIG. 5is side view of a tool bit securing system for the first tool bit, in accordance with an embodiment of the present disclosure. In particular,FIG. 5is a side view500of the tool bit securing system502for the tool bit102. The securing system502includes a mold board504. In some embodiments, the mold board504is a portion of a motor grader machine (not depicted) and serves as an interface between the machine and the tool bits that interact with the ground surface. The mold board504attaches to a back surface508of an adapter board506. The adapter board506includes a leading edge514that includes a bore hole516. The bore hole516is configured and sized to receive the threaded portion108of the tool bit102.

The leading edge514may be angled from the remainder of the adapter board506in order to provide a proper engagement angle of the working portion104of the tool bit102with the ground surface. As a result, a clearance region510is defined by a bottom edge512of the mold board504and a back surface508of the leading edge514. The clearance region510provides for limited access to the threaded portion108of the tool bit. As such, it may be difficult to obtain proper room in the vicinity of the clearance region510in order to apply a torque wrench or a socket wrench to a nut in order to secure the tool bit102to the adapter board506. Thus, it may be advantageous, but difficult, to torque an applied nut to the threaded portion108in order to minimize backing the off of nuts. The subsequent disengagement between the nuts and the threaded portion, due to vibrations experienced during operation, may cause loss of the tool bit102.

As seen inFIG. 5, the tool bit102is inserted into the bore hole516, which extends through the leading edge514from the clearance region510to the front surface518of the adapter board506. The threaded portion108of the tool bit102extends into the clearance region510, and the shank112is disposed within the bore hole516. The shoulder128abuts against a surface of the adapter board506, thus limiting the protrusion of the threaded portion108into the clearance region510.

When the tool bit102is secured into the adapter board506, the shank112of the tool bit102is inserted through the bore hole516of the adapter board506, the threaded portion108extends from the bore hole516into the clearance region510, the threads204of the nut202are engaged with the threaded portion108of the tool bit102, the pin302is inserted through two opposing slots206of the plurality of slots of the nut202and the anti-rotation receiving hole114.

The tail ends306of the pin302are deformed around the nut202and the eyelet304prevents the pin302from sliding through the anti-rotation receiving hole114. The tail ends306are configured such that a first tail end306may be deformed in a clockwise direction around the nut202and the second tail end306may be deformed in a counter-clockwise direction around the nut202.

The upright members208thus prohibit the nut202from rotating when the pin302is installed into the anti-rotation receiving hole116through the slots206. It is envisioned that items other than a pin302may be inserted through the anti-rotation receiving hole114in order to prevent rotation of the nut202. For example, lock wire may be inserted through the anti-rotation receiving hole114and twisted together to prevent the nut202from rotating.

FIG. 6is a perspective view of the front of a tool bit securing system, in accordance with an embodiment of the present disclosure. In particular,FIG. 6depicts the view600of the tool bit securing system502. Here, a plurality of tool bits102are secured into the adapter board506. In some embodiments, each of the tool bits102may be secured by the aspects disclosed related to the tool bit securing system502. However, it is envisioned that in some embodiments only one tool bit102is secured via the system502, while other types of tool bits, and their associated tool-bit securing systems, may be used to secure the other tool bits to the adapter board506.

The adapter board506includes the anti-rotation slot602. Here, the anti-rotation slot602is realized by flat surfaces on either side of the tool bit that interact with the anti-rotation segment118of the tool bit102. For example, the tool bit102may include the flat side120that abuts against the anti-rotation slot602when secured into the adapter board506. The engagement of the two flat surfaces prevents rotation of the tool bit102about its longitudinal axis116.

In some embodiments, the tool bit102is secured via a nut202being hand-tightened to the threaded portion108of the tool bit102. The hand-tight engagement prevents the tool bit102from translating along its longitudinal axis. However, the hand-tight engagement may not provide sufficient pressure between the tool bit102and the adapter board506to prevent rotation about its longitudinal axis116without incorporation of the anti-rotation segment118and the anti-rotation slots602of the adapter board506.

FIG. 7is a perspective view of the back of the tool bit securing system, in accordance with an embodiment of the present disclosure. In particular,FIG. 7depicts the perspective view700of the back of the tool bit securing system502depicted in the view600ofFIG. 6. Here, a nut202is engaged with the threaded portion108of the tool bit102that extends into the clearance region. A pin302is inserted through the anti-rotation receiving hole114, and each of the pins302and their respective anti-rotation receiving holes114are oriented along an axis that is parallel to the axis of the working edge124. As such, this orientation permits increased access by an installer to the tail ends306of the pins302when they are deformed about the nut202.

In some embodiments, the securing system502further includes a washer406disposed about the threaded portion108of the tool bit102and between the nut202and the adapter board506. The washer406may provide for a more uniform distribution of forces between the nut202and the adapter board506.

In some other embodiments, the adapter board506may include cutouts702around the bore hole516. The cutouts702provide for a larger clearance region510to permit increased access to the threaded portion108of the tool bit102.

FIG. 8is a perspective view of a second tool bit, in accordance with an embodiment of the present disclosure. In particular,FIG. 8depicts the view800of the tool bit802. The tool bit802is similar to the tool bit102. However, the threaded portion108includes threads on an inner surface (e.g., the internally threaded portion808) that are configured to receive a retention bolt804. The retention bolt804may be a threaded bolt, with its threads configured to engage with the internally threaded portion808of the tool bit802. The distal end106of the tool bit802may be similarly designed as the distal end106of the tool bit102, and thus include the cutting surface122, the anti-rotation segment118, the shoulder128, and the like.

In such an embodiment, the shank812of the tool bit802is configured not to extend into the clearance region510. To secure the tool bit802into the adapter board506, the shank of the tool bit802may be inserted into the bore hole516, a washer406may be disposed about the retention bolt804, and the retention bolt804may be inserted into (e.g., threaded into) the internally threaded portion808of the tool bit802via access from the clearance region510.

Due to the retention bolt804having a lower profile (e.g., it does not extend as far into the clearance region510), the retention bolt804may be torqued with a tool (e.g., by a wrench or a socket) in order to provide sufficient tightness to prevent the retention bolt804from backing from vibrations experienced during normal operations. Such a system802provides for a reduction of parts as compared to tool bit securing system502. This is because the system802does not require use of a pin302and replaces the nut202with the retention bolt804. Further, the additional manufacturing step of drilling of an anti-rotation receiving hole114is also not required.

FIG. 9is a side view of a tool securing system, securing the tool bit depicted inFIG. 8, in accordance with an embodiment of the present invention. In particular,FIG. 9depicts the side view900. The side view900is similar to the side view500, but instead depicts the tool bit802being secured to the adapter board506with a retention bolt804.

As depicted in the view900, the head of the retention bolt804extends into the clearance region510. The working portion104is similar to that of the working portion104of the tool bit102.

INDUSTRIAL APPLICABILITY

In general, the teachings of the present disclosure may find applicability in many motor grader application. For instance, the teachings of the present disclosure may be applicable to any motor grader machines of differing sizes and orientations and for working on different road and ground surfaces.

FIG. 10is a perspective view of the rear of a motor grader having a plurality of tool bits secured to an adapter board, in accordance with an embodiment of the present disclosure. In particular,FIG. 10depicts the perspective view1000of the rear of the motor grader1002that implements the tool bit securing systems502and902to secure the respective tool bits102and802.

Here, a portion of the mold board504on the right portion of the motor grader1002provides for a narrower clearance region510than does the center portion of the motor grader blade1002. As such, the tool bits102are installed into the eight right-most bore holes516via the tool bit securing system502. This includes a tool bit102having a threaded portion108configured being inserted through a respective bore hole516into the clearance region510. A nut202is threaded onto the threaded portion108of the tool bit102, and a pin302is inserted through the anti-rotation receiving hole114to restrain the nut202from rotating.

In the middle portion of the motor grader1002, a larger clearance region510may exist as the attachment portion of the mold board504may not provide for such a limited size of the clearance region510. As such, the tool bits802may be secured into the adapter board506via a retention bolt804engaging with the internally threaded portion808of the tool bit802. These retention bolts804may be secured by torquing the retention bolts804with a torque wrench in order to sufficiently secure the tool bit802to the adapter board506.

It is further envisioned that each bore hole516in the adapter board506may be configured to receive either of the tool bit102or the tool bit802, thus permitting installation of any available tool bit (102or802) into the respective bore hole516. While the view1000depicts a mixture of tool bits102and802being installed in to the motor grader1002, it is envisioned that a motor grader1002may realize only one of the tool bit securing systems throughout the entirety of the bore hole516in the adapter board506.