Angle positioning tool and hand-scaler grinding device using same

The object of the present invention is to provide an angle setting tool for setting the blade section of a hand scaler at a predetermined angle during sharpening of the scaler, and a hand scaler sharpening device which has a relatively simple structure, is easy to operate and do maintenance, and reduces complexity in the sharpening operation. This object is achieved by a hand scaler sharpening device including a sharpener main body having a grind stone (50) provided for reciprocating motion, and an angle setting tool (41) for setting the tip of a hand scaler at one of a plurality of predetermined angles on the grind stone (50), wherein the angle setting tool (41) has a plurality of inclined surfaces (42a, 43a, 44a) corresponding to the predetermined angles.

10505750 is a national stage entry of PCT/JP03/01911, International Filing Date: 21 Feb. 2003, and claims foreign priority from JP 2002-51395, filed 27 Feb. 2002 and PCT/JP02/07048, International Filing Date Jul. 11, 2002.

FIELD OF ART

The present invention relates to an angle setting tool for use in sharpening a hand scaler, and a hand scaler sharpening device using the same. The present invention relates in particular to an angle setting tool for use in sharpening and repairing cutting edges of hand scalers, such as curet or sickle scalers, which are used for removing dental calculus, plaques, and the like, and to a hand scaler sharpening device using the tool.

BACKGROUND ART

Hand scalers are used for removing dental calculus and the like, and have, for example, as shown inFIGS. 12 and 13, grip section52to be grasped by an operator, shank sections53provided on both ends of the grip section52, and blade sections54located at the tip of the shank sections53.

As shown inFIGS. 14 and 15, the blade section4of hand scaler50has sharpened cutting edges54a, the tip of the blade section54, i.e., toe56is formed rounded, and back face54bis formed on the side opposite to the cutting edges54a. The cutting edges54aare used for scaling off dental calculus and the like, and the toe56is rounded so as not to hurt the dental gum upon accidental contact during the calculus removal.

The hand scaler having the blade section54with the rounded tip or toe56is called a curet hand scaler, while a hand scaler having a blade section with a pointed tip is called a sickle hand scaler.

Various types of curet and sickle scalers are available of which blade sections have different shapes of axes. For example,FIG. 14illustrates a blade section54of a curet hand scaler, wherein the axis of the blade section extends in an arc shape.FIG. 16illustrates a blade section64of a sickle hand scaler, wherein the axis of the blade section extends substantially straight.FIG. 17illustrates a blade section74of another curet hand scaler, wherein the axis of the blade section is formed in an intermediate shape between a straight line and a mild arc. The blade sections64and74also have, like the blade section54, cutting edges64a,74aand a back face64b,74b, respectively. The apex of the blade section64is pointed and called tip66, whereas the apex of the blade section74is rounded to form toe76.

As the hand scalers are used for removing calculus, their cutting edges become blunt due to abrasion, so that the edges have to be sharpened and repaired as necessary. Known apparatus for such repairing includes a manual type, wherein the grind stone is moved manually, and a motor-driven type, wherein the grind stone is moved by means of an electric motor or the like.

However, the conventional motor-driven apparatus has problems in that the blade tends to be ground excessively and prematurely worn, and that the apparatus is complex in structure and expensive. In order to prevent such excessive grinding of the blade, means have been proposed for adjusting the contact angle of the cutting edge to the grind stone. However, such adjusting means disadvantageously complex the apparatus structure and handling in maintenance. Thus a hand tool is demanded for easy re-sharpening of hand scalers in situ as desired.

For solving these problems, the present applicant proposed in JP-2001-38584-A a hand scaler sharpener apparatus including a sharpener main body having a grind stone capable of reciprocating, and a detachable attachment. This attachment includes a positioning plate for properly positioning a scaler tip on the grind stone, and having a notch formed in an arc shape substantially corresponding to the arc shape of the blade section of the hand scaler.

With the above-mentioned hand scaler sharpening apparatus, the hand scaler is held in hand, the back face of the blade section is pressed against the arc notch of the positioning plate, and the contact angle between the cutting edge of the blade section and the grind stone is adjusted under visual observation, while the grind stone is reciprocatingly driven. Thus the contact angle between the cutting edge and the grind stone may not be set properly, depending on the experience of the operator who does the sharpening.

In order to minimize such an error in the contact angle, the applicant further proposed in JP-2001-54840-A a hand scaler sharpening apparatus having an angle indication means in addition to the apparatus composition disclosed in the above JP-2001-38584-A. This angle indication means has angle indication lines or angle indication axes, and is positioned along the grind stone and the positioning plate. The operator presses the back face of the blade section of a hand scaler to the arc notch of the positioning plate, views the scaler against a background the angle indication means, and manually adjusts the angle of the scaler so that the axis of the shank section is in alignment with a particular background angle indication line or an angle indication axis, to thereby adjust the contact angle between the cutting edge and the grind stone.

The apparatus disclosed in JP-2001-54840-A indeed enables relatively accurate setting of the contact angle between the cutting edge and the grind stone, but the complexity in setting the contact angle is not sufficiently dissolved.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an angle setting tool that enables relatively easy and accurate setting of a blade section of a hand scaler at a desired angle for sharpening.

It is another object of the present invention to provide a hand scaler sharpening device that has a relatively simple structure, is easy to operate and do maintenance, and reduces complexity in setting the angle between the blade section and the grind stone for sharpening.

According to the present invention, there is provided an angle setting tool to be placed on a grind stone for setting a blade section of a hand scaler at a predetermined angle during sharpening of the blade section, said angle setting tool comprising at least one inclined surface inclined at a predetermined angle with respect to a bottom surface of said tool.

The angle setting tool according to the present invention is to be placed, for use, on a grind stone capable of reciprocating or on a stationary grind stone. When the angle setting tool is to be used on a stationary grind stone, the shank section of a hand scaler to be sharpened is pressed against one of the inclined surfaces of the setting tool, while the back face of the blade section of the scaler is pressed against a surface facing to that inclined surface. Then the scaler is fixed to the setting tool with fingers or the like so that the relative position between the scaler and the setting tool is not changed, and the scaler and the tool together are moved on the grind stone. In this state, the shank section is kept at a predetermined angle defined by the inclined surface of the setting tool, while the blade section is slid on the grind stone at a constant angle with respect to the grind stone, so that the cutting edge is sharpened to have a predetermined angle. Thus the blade section of a hand scaler may be kept at a predetermined angle while being sharpened, simply by moving the setting tool with the hand scaler on a stationary grind stone. The operation and the maintenance of the setting tool are easy, and the complexity experienced in setting the angle of the blade section for sharpening may be reduced.

The angle setting tool according to the present invention may optionally have a slit along the lower end of each inclined surface.

The width of the slit may be such that, when the shank section of a scaler is pressed against the inclined surface and the blade section of the scaler is placed on the grind stone, the back face of the blade section is pressed against the surface facing to the inclined surface to fix the angle of the cutting edge of the blade section with respect to the upper surface of the grind stone.

The angle setting tool according to the present invention may optionally have a notch in the form of an arc substantially corresponding to the arc of the blade section of the hand scaler.

The angle setting tool of the present invention may further have a hole for receiving the toe of a curet hand scaler for rounding by grinding.

According to the present invention, there is also provided a hand scaler sharpening device having the angle setting tool mentioned above, and a sharpener main body including a grind stone capable of reciprocating.

With the hand scaler sharpening device of the present invention, by simply holding a hand scaler in hand and pressing the shank section of the scaler against one of the inclined surfaces of the angle setting tool, the contact angle of the cutting edge of the scaler with respect to the grind stone is properly set, and the cutting edge is sharpened to have an appropriate angle. In addition, since each inclined surface is formed to provide a different angle, an inclined surface of an appropriate, desired angle may be selected for sharpening the cutting edge to have a desired angle.

The angle setting tool of the hand scaler sharpening device according to the present invention may optionally have a slit along the lower end of each inclined surface.

The width of the slit may be such that, when the shank section of a hand scaler is pressed against the inclined surface and the blade section of the scaler is placed on the grind stone, the back face of the blade section is pressed against the surface facing to that inclined surface to fix the angle of the cutting edge of the blade section with respect to the upper surface of the grind stone.

The angle setting tool may have at least one projected portion, and the at least one inclined surface may be provided on that projected portion.

Further, a pair of the projected portions may be provided spaced apart from each other for allowing reciprocating motion of the grind stone between the projected portions.

PREFERRED EMBODIMENTS OF THE INVENTION

The present invention will now be explained with reference to preferred embodiments thereof taken in conjunction with the attached drawings.

FIG. 1is a plan view of angle setting tool41as an embodiment of the present invention, andFIG. 2is a sectional view of the tool taken along lines II—II inFIG. 1.

The angle setting tool41is a plate-like member made of, for example, stainless steel, and having a generally rectangular top plan shape, with at least the bottom surface48being formed flat. The angle setting tool41has three openings42,43,44formed in the upper face, which openings are used for sharpening cutting edge64aof blade section64having the axis extending substantially straight as shown inFIG. 16, or cutting edge74aof blade section74having the axis formed in an intermediate shape between a straight line and an arc as shown inFIG. 17. Each of the openings42,43,44is defined by inclined surface42a,43a,44aagainst which the shank section of a hand scaler is to be pressed, vertical surface42b,43b,44bfacing to each inclined surface, and slit42c,43c,44cthrough the bottom surface48.

In this embodiment, the inclined surfaces42a,43a,44aare formed at α=40°, β=30°, and γ=20° with respect to the bottom surface, respectively. However, the angles of the inclined surfaces42a,43a,44aare not limited to these angles, and may suitably be formed at different angles depending on the angles to be given to the cutting edge64a,74a. The width of each slit42c,43c,44c, that is the width of each slit in the direction of arrow W inFIG. 1, is decided such that, when the shank section63,73of a hand scaler is pressed against the inclined surface42a,43a,44aand the blade section64,74of the scaler is placed on the grind stone, the back face64b,74bof the blade section64,74is pressed against the vertical surface42b,43b,44b, to fix the blade section64,74at a predetermined angle with respect to the upper surface of the grind stone.

Further, the angle setting tool41has hole46formed in the inclined surface44athrough the bottom surface, notch47in the form of an arc formed in the side edge of the inclined surface44a, and slot45to be used for fixing the angle setting tool41with a screw or the like. The hole46is used by inserting the toe of a curet hand scaler into this hole and turning around the toe therein for rounding. The notch47in the form of an arc is used for sharpening cutting edge54aof blade section54in the form of an arc as shown inFIG. 14, and is formed in an arc shape substantially corresponding to the arc shape of the blade section54. With this notch, the cutting edge54aof the scaler is sharpened by moving the blade section54along the arc notch surface, with the shank section53of the scaler being kept at about 20° to 30°.

Next, how to use the angle setting tool41of the present invention is to be explained.

The angle setting tool41is placed on a grind stone50as shown inFIG. 4. The blade section64is inserted into, for example, the opening43and positioned on the grind stone50seen through the slit43c. The shank section63is pressed against the inclined surface43a, while the back face64bof the blade section64is pressed against the vertical surface43b. In this position, the cutting edge64bof the blade section64is set in a pressed position against the upper surface of the grind stone50at a predetermined angle. Then with the hand scaler being held to the angle setting tool41with fingers or the like so that the relative position of the blade and shank sections64and63with respect to the tool41is not changed, the scaler and the tool41together are moved on the grind stone50. The blade section64is kept at a constant angle and slid on the grind stone with the shank section63being kept at a constant angle defined by the inclined surface43aof the tool41, so that the cutting edge64ais sharpened to have a predetermined angle. Here, when the hand scaler and the angle setting tool41are reciprocated on the grind stone50, the grind stone50stays stationary.

As discussed above, the blade section of the scaler may be sharpened simply by sliding the angle setting tool41with the hand scaler on the stationary grind stone50. Thus maintenance and operation are easy, and the complexity in setting the angle of the blade section for sharpening is reduced.

While the use of the angle setting tool41on a stationary grind stone is discussed above, the tool41may be used in any manner without limitation, and may be combined with a sharpener main body having a grind stone which is provided for reciprocating motion, as will be discussed below.

FIG. 5is a perspective view of an embodiment of the hand scaler sharpening device of the present invention, andFIG. 6is a perspective view of the hand scaler sharpening device ofFIG. 5shown exploded into a sharpener main body11and an angle setting tool21.

The sharpener main body11has grind stone13, body section15, grind stone holder member14which detachably holds the grind stone13and is capable of reciprocating on the surface of the body section15, and a switch (not shown) for starting and stopping the reciprocating motion of the grind stone holder member14. The body section15accommodates therein, though not show in the drawings, a drive unit, such as a motor, a battery as a power source for the drive unit, and a transmission mechanism, such as link mechanisms and cams, for transmitting the force from the drive unit to the grind stone holder member14to effect the reciprocating motion. With this structure, by turning the switch on, the grind stone holder member14with the grind stone13reciprocates in the direction of arrows M.

The angle setting tool21is detachably mounted on the sharpener main body11, and has recess26in its bottom surface for providing clearance between the tool21and the reciprocating grind stone13as shown inFIG. 6. The angle setting tool21is also provided with three openings22,23,24, which are used for sharpening the cutting edge64aof the blade section64having the axis extending substantially straight as shown inFIG. 16, or the cutting edge74aof the blade section74having the axis formed in an intermediate shape between a straight line and an arc as shown inFIG. 17. Each of the openings22,23,24is defined by inclined surface22a,23a,24a, vertical surface22b,23b,24bfacing to each inclined surface, and slit22c,23c,24c. The inclined surfaces22a,23a,24aare formed at 30°, 40°, and 50° with respect to the bottom surface of the angle setting tool21, more specifically, the bottom surface at the recess26, respectively. However, the angles of the inclined surfaces22a,23a,24aare not limited to these angles, and may suitably be formed at different angles depending on the angles to be given to the cutting edge64a,74a.

Further, the gap between each inclined surface22a,23a,24aand the corresponding vertical surface22b,23b,24bis formed in a size such that, for example as shown inFIG. 7, when the shank section of a hand scaler is pressed against the inclined surface22a,23a,24aand the blade section74of the scaler is placed on the grind stone13, the back face74bof the blade section74is pressed against the vertical surface22b,23b,24b, and the reaction force from the vertical surface prevents displacement of the blade section74.

The angle setting tool21is also provided with a slot25, through which screw26is inserted and tightened into a screw hole in the sharpener main body11. The angle setting tool21is detachably fixed to the sharpener main body by means of tightening or loosening of this screw26.

The angle setting tool21is shown to have the recess26for providing clearance between the tool21and the reciprocating grind stone13. However, this recess26is not always necessary depending on the configuration of the sharpener main body11. For example, though not shown, the recess26may be eliminated if the body section15is provided in its surface with a depression, in which the grind stone holder member14and the grind stone13are disposed for reciprocating motion, with the top surface of the grind stone13being out of touch with the bottom surface of the angle setting tool21. With this structure, even the angle setting tool41having a flat bottom surface may be attached to and used with the sharpener main body.

FIG. 7is a schematic view showing how a curet hand scaler is sharpened by means of the hand scaler sharpening device10. This is explained with reference toFIGS. 5 and 7. Incidentally, whileFIG. 7shows only a curet hand scaler, it is understood that the hand scaler sharpening device10may also be used for sickle scalers as well.

InFIG. 7, for sharpening the hand scaler, the shank section of the hand scaler is pressed against the inclined surface24aand the cutting edge74ais pressed against the grind stone13, while the back face74bof the blade section74is pressed against the vertical surface24b. In this position, the angle α° of the blade section74with respect to the grind stone13is set. When the switch is turned on, the grind stone13reciprocates in the direction of arrows M, while the angle setting tool21and the blade section74of the hand scaler1remain stationary. The contact angle of the blade section74with respect to the grind stone13is kept constant, so that the cutting edge74ais sharpened to have a desired angle by means of the relatively reciprocating grind stone13.

As discussed above, the shank section73is pressed against any of the inclined surfaces22a,23a,24a, and the back face74bof the blade section74is pressed against the corresponding vertical surface22b,23b,24b. Thus the displacement of the blade section4in the direction of the reciprocating motion of the grind stone13or the direction transverse thereto may be prevented simply by properly adjusting the magnitude of the force to be applied to the hand scaler.

Next,FIG. 8shows, in perspective, another hand scaler sharpening device80, which is different from the embodiment shown inFIG. 5.FIG. 9illustrates the angle setting tool used in this hand scaler sharpening device.

Referring toFIG. 8, hand scaler sharpening device80includes sharpener main body11and angle setting tool81. The angle setting tool81has slot85, through which screw87is inserted and tightened into a screw hole in the sharpener main body11to detachably fix the angle setting tool81. Here, the sharpener main body11is the same as the one inFIG. 5, so that detailed explanation regarding its structure is eliminated.

The angle setting tool81may be detachably fixed to the sharpener main body11, and has three openings82,83,84, each of which is defined by inclined surface82a,83a,84a, vertical surface82b,83b,84bfacing to each inclined surface, and slit82c,83c,84c. The inclined surfaces82a,83a,84aare formed at different angles with respect to the bottom surface of recess86in the angle setting tool81. These structures are almost the same as those in the angle setting tool21ofFIG. 5, but differ in that the inclined surfaces82a,83a,84aand the vertical surfaces82b,83b,84bof the angle setting tool81extend over the full width in the direction of arrow S inFIG. 9.

As shown inFIG. 9, the angle setting tool81has recess86formed in its bottom surface for providing clearance between the tool81and the reciprocating grind stone13, and lateral sections87a,87barranged on both sides of the recess86. The inclined surfaces82a,83a,84and the vertical surfaces82b,83b,84bextend over the lateral sections87a,87b. By arranging the inclined surfaces82a,83a,84aand the vertical surfaces82b,83b,84bto extend over the entire width in the direction of the arrow S, the shank section73will not contact the lateral sections87a,87bwherever in the lateral direction the blade section74is positioned on the grind stone13during sharpening, to thereby facilitate sharpening operation of the hand scaler.

Another hand scaler sharpening device30, which is different from those shown inFIGS. 5 and 8, is shown inFIG. 10in perspective, and inFIG. 11in an exploded view.

Referring toFIGS. 10 and 11, the hand scaler sharpening device30includes sharpener main body11and angle setting tool31. Here, the sharpener main body11is the same as the one inFIG. 5, so that detailed explanation regarding its structure is eliminated.

The angle setting tool31may be detachably fixed to the sharpener main body11, and has recess formed in its bottom surface for providing clearance between the tool31and the grind stone13of the sharpener main body11. As shown inFIG. 11, the angle setting tool31has cut-out32, on both sides of which projections34,34are provided. These two projections34,34are spaced apart from each other for allowing reciprocating motion of the grind stone13therebetween. Each of the projections34has inclined surface section33having a plurality of inclined surfaces33a,33b,33cformed at different angles with respect to the bottom surface of the angle setting tool31. The inclined surfaces are formed to define the angle to be given to the cutting edge4aby sharpening, depending on the angle of the inclined surface selected.

Vertical surface32afacing to the inclined surface section33is shown inFIG. 10at a distance from the inclined surface section33for not allowing contact of a back face of the blade section74thereto. However, it is understood that the distance between the inclined surface section33and the facing surface32amay suitably be closed to allow contact of the back face of the blade section74to the facing surface32awhen the shank section of the hand scaler is pressed against the inclined surface33a,33b,33c, to prevent displacement of the blade section74with the reaction force from the facing surface32a.

The angle setting tool31has slot35, through which screw36is inserted and tightened into a screw hole in the body section15to detachably fix the angle setting tool31.

Sharpening of the cutting edge74amay be performed with the hand scaler sharpening device30in the similar manner as with the hand scaler sharpening device10.

Specifically, for sharpening the hand scaler1, the shank section73of the hand scaler is pressed against one of the inclined surfaces33a,33b,33c, while the cutting edge74ais pressed against the grind stone13. In this position, the contact angle of the blade section74with respect to the grind stone13is set. When the switch is turned on to operate the hand scaler sharpening device10, the grind stone13reciprocates in the direction of arrows M, while the angle setting tool31and the blade section74remain stationary on the grind stone13. The cutting edge74ais sharpened with the grind stone13to have a desired angle by the relatively reciprocating motion of the grind stone13.

The hand scaler sharpening device30has the projections34arranged on the opposite sides of the grind stone13. This is because one blade has two cutting edges on its opposite sides, with the direction of the blade axis upon sharpening one of the cutting edges being opposite to the direction of the axis upon sharpening the other. When the sharpening of one cutting edge is completed on one of the projections34, the inclined surface33a,33b,33cof the other of the projections34is used for sharpening the other cutting edge.

The hand scaler sharpening device according to the present invention has a sharpener main body of a simple structure having a grind stone provided for reciprocating motion, and an angle setting tool provided with a plurality of inclined surfaces at predetermined angles for setting the tip of a hand scaler on the grind stone at a plurality of predetermined angles. Thus in the sharpening operation, by simply grasping the hand scaler with hand and pressing the shank section against one of the inclined surfaces, the contact angle of the cutting edge with respect to the grind stone may be set optimally, and the cutting edge may be sharpened to have a desired angle.

Therefore, the present invention provides, with a relatively simple structure, optimal setting of a contact angle of the cutting edge of a hand scaler with respect to the grind stone for sharpening, simply by pressing the hand scaler against the inclined surface. Thus the complexity in the sharpening operation may be reduced.