Mountings for riving knives of table saws

• US 20050211034A1
• Filed: 03/11/2005
• Published: 09/29/2005
• Est. Priority Date: 03/12/2004
• Status: Active Grant

• Current Assignee: Makita Corporation
• Original Assignee: Makita Corporation
• Inventors: Uchida, Masaaki, Sasaki, Katsuhiko, Sugiura, Takehiko, Inai, Masahiko
• Granted Patent: US 7,540,223 B2
• Time in Patent Office: Days
• US Class Current: 83/102.100
• CPC Class Codes: B27G 19/02 for circular saws
• CPC Class Codes: B27G 19/08 Accessories for keeping open the saw kerf, e.g. riving knives or wedge plates
• CPC Class Codes: Y10T 83/2077 By kerf entering guide
• CPC Class Codes: Y10T 83/773 Work-support includes passageway for tool [e.g., slotted table]
• CPC Class Codes: Y10T 83/7734 With guard for tool

Abstract

A device for mounting a cover of a cutting blade to a riving knife may have an engaging member for releasably engaging at least a part of the riving knife from both sides, in a direction of thickness of the riving knife. The engaging member is manually operable without any additional tools. A device for mounting a riving knife to a table saw may include a manually operable lock member and a biasing member. The biasing member is arranged and constructed to normally bias the lock member towards a lock position. The riving knife may be divided into a first knife portion and a second knife portion. A positioning device may position the first knife portion and the second knife portion substantially within a single plate.

Claims

1. A combination comprising a riving knife and a device for mounting a cover of a cutting blade to the riving knife,

wherein the riving knife has an upper edge, a rear edge, and a cavity formed in at least a part of the riving knife;

and

wherein the mounting device comprises;

a support member arranged and constructed to support the cover, and

an engaging member coupled to the support member and arranged and constructed to releasably engage the cavity firmed in the riving knife.

2. The combination as in claim 1,

wherein the support member comprises a support bracket arranged and constructed to contact with the upper edge of the riving knife;

and

wherein the engaging member comprises a joint plate coupled to the support bracket, so that the joint plate can move substantially within the same plane as the riving knife; and

wherein the joint plate includes at least one first joint portion having a thickness equal to or smaller than a thickness of the riving knife and engageable with corresponding at least one fist joint recess formed in the upper edge of the riving knife, so that the first joint portion is prevented from moving relative to the riving knife with respect to the thickness and does not extend outward from the corresponding first joint recess in the direction thickness when the fist joint portion engages with the first joint recess of the riving knife.

3. The combination as in claim 2,

wherein the joint plate has a plurality of first joint portions for engaging corresponding first joint recesses formed in the riving knife, and

wherein each of the first joint portions has a tapered outer circumferential surface inclined with respect to the direction of thickness of the joint plate, and

wherein the first joint portions arm arranged in a first direction along the joint plate such that the tapered directions of the outer circumferential surfaces are alternately opposite in the fist direction, and

wherein the riving knife has a plurality of first joint recesses having tapered inner circumferential surfaces corresponding to the outer circumferential surfaces of the first joint portions, and

wherein the mounting device further comprises means for pressing the support bracket against the upper end of the riving knife and for forcing the joint plate to move upward away from the riving knife, so that upper portions of the tapered outer circumferential surfaces of the first joint potions are forced to contact upper portions of the tapered inner circumferential surfaces of the first joint recesses.

4. The combination as in claim 3, wherein pressing means comprises a tread mechanism arranged and constructed to apply a lifting force to the joint plate and to apply a pressing force to the support bracket as a reaction force of the lifting force.

5. The combination as in claim 3,

wherein a substantially V-shaped guide projection is formed along the length of a lower edge of the support bracket and is engageable with a corresponding V-shaped guide recess formed in the upper edge of the riving knife along the length of the upper edge, so that the guide projection and the guide recess engage with each other when the support bracket is pressed against the upper edge of the riving knife.

6. The combination as in claim 2,

wherein the support bracket is arranged and constructed to contact with the rear edge of the riving knife in addition to the upper edge;

and

wherein the joint plate is pivotally mounted to the support bracket; and

wherein the support bracket includes at least one second joint portion having a thickness equal to or smaller than a thickness of the riving knife and engageable with corresponding at least one second joint recess formed in the rear edge of the riving knife, so that the second joint portion is prevented from moving relative to the riving knife with respect to the thickness and does not extend outward from the correspond second joint recess in the direction thickness when the second joint portion engages with the second joint recess of the riving knife; and

wherein the joint plate is operable to engage the first joint portion with the first joint recess with the second joint portion engaged with the second joint recess, so that the support brackets is fixed in position relative to the riving knife while the support bracket contacting with both the upper edge and them rear edge.

7. The combination as in claim 6,

wherein the joint plate has a plurality of second joint portions for engaging corresponding second joint recess formed in the riving knife, and

wherein each of the second joint portions has a tapered outer circumferential surface inclined with respect to the direction of thickness of the joint plate, and

wherein the second joint portions are arranged in a second direction such that the tapered directions of the outer circumferential surfaces are alternately opposite in the second direction, and

wherein the second joint recesses having tapered inner circumferential surfaces corresponding to the outer circumferential surfaces of the second joint portions.

8. The combination in claim 6, further comprising a biasing member arranged and constructed to normally bias the joint plate in a direction for engagement of the fist joint portion with the first joint recess.

9. The combination as in claim 6, flier comprising a guide member arranged and constructed to engage the upper edge of the riving knife in order to position the joint plate relative to the riving knife in the direction of thickness when the joint plate has been pivoted to a position where the first joint portion is disengaged from the first joint recess.

10. The combination as in claim 1,

wherein the engaging member compress a pair of resiliently deformable plates defining an insertion recess therebetween, the insertion recess having a width for permitting insertion of a part of the riving knife, and

wherein the mounting device further comprises a lever mounted to the support member and operable between a mounting position and a releasing position, and

wherein the resiliently deformable plates are resiliently deformed to narrow the width of the insertion recess so as to clamp the part of the riving knife therebetween when the lever is operated to the mounting position.

11. The combination as in claim 10,

wherein the resiliently deformable plates have inner walls opposing to both sides of the riving knife, and

wherein projections formed on the inner walls of the resiliently deformable plates in order to engage corresponding engaging holes formed in the flying knife.

12. The combination as in claim 10,

wherein the resiliently deformable plates have outer walls, and,

wherein pressing projections are formed on the outer walls, so that the lever engage with the pressing projections to urge the resiliently deformable plates to narrow the width of the insertion recess, when the lever has been moved to the mounting position.

13. The combination as in claim 1,

wherein the engaging member comprises a claw base arranged and constructed to clamp a part of the riving knife against the support member.

14. The combination as in claim 13,

wherein the clamp base is coupled to the support member via a threaded shaft ending through the clamp base, the threaded shaft having a first end mounted to the support member and having a second end extending outward from the clamp base, and

wherein the mounting device further comprises a nut engaging with the second end of the threaded shaft, and a lever joined to the nut, so that the part of the riving knife is clamped between the support member and the clamp base as the lever is pivoted to a mounting position to tighten the nut.

15. The combination as in claim 14,

wherein the support member comprises a mount base having an engaging projection and a support projection formed on a surface opposing to the clamp base, and

wherein the engaging projection is configured to engage a corresponding engaging recess formed in an upper portion of the riving knife when the riving knife has been clamped;

and

wherein the support projection being positioned in a position opposite to the engaging projection with respect to the threaded shaft, so that the clamp base pivots about the support projection as the clamp base moves toward and away from the mount base by the pivotal operation of the lever.

16. The combination as in claim 14,

wherein the mount base includes a first contact portion and a second contact portion respectively contacting with the upper edge and the rear edge of the riving knife.

17. A table saw comprising the combination of the riving knife and the mounting device as defined in claim 1 and further comprising a table for placing thereon a workpiece, so that the workpiece is cut by the cutting blade as the workpiece is moved along the table,

wherein the riving knife is positioned on the rear side of the cutting blade substantially within the sane plane as the cutting blade.

18. A combination comprising a riving knife and a device for mounting the riving knife to a table saw,

wherein the mounting device comprising:

a manually operable lock member movable between a lock position and an unlock position in order to lock and unlock at least a part of the riving knife; and

a biasing member arranged and constructed to normally bias the lock member toward the lock position.

19. The combination as in claim 18,

wherein the mounting device further comprises a mount member defining a mount recess for receiving at least a part of the riving knife, and

wherein the lock member comprises a lock pin supported by the mount member, and

wherein the lock pin is positioned to extend into the mount recess in order to engage the part of the riving knife and to prevent the riving knife from being removed from the mount recess when the lock pin is in the lock position.

20. The combination as in claim 19,

wherein the mount member comprises a mount base and a holder plate attached to the mount base, so that the mount recess is defined between the mount base and the holder place;

and

wherein the lock pin is axially slidably inserted into the mount member, so that the lock pin moves between the lock position and the unlock position in the axial direction.

21. The combination as in claim 20,

wherein the lock pin extends trough a lock hole formed in a base portion of the riving knife;

and

wherein the lock pin has a tapered portion that is configured to engage the lock hole when the lock pin is in the lock position.

22. The combination as in claim 18,

wherein the mounting device further comprises a mount base and a holder plate defining a mount recess therebetween for receiving at least a part of the riving knife, and

wherein the lock member comprises the holder plate and is movable relative to the mount base in order to clamp and unclamp the part of the riving knife.

23. The combination as in claim 22;

wherein at least one of the mount base and the holder plate is engageable with the riving knife in the direction of thickness of the riving knife in order to prevent the riving knife from being removed from the mount recess when the holder plate is positioned in the lock position.

24. The combination as in claim 22,

wherein the mounting device further comprises:

a threaded shaft rotatably inserted into the mount base and having a first end and a second end, and

an operation lever threadably engaged with the first end of the threaded shaft,

wherein the holder plat is coupled to the second end of the threaded shaft, so that the threaded shaft does not rotated relative to the holder plate, and

a cam mechanism disposed between the operation lever and the mount base, so that the threaded shaft moves in the axial direction to move the holder plate to the lock position in response to the pivotal option of the operation lever.

25. The combination as in claim 24, further comprising a rotation prevention mechanism disposed between the holder plate and the mount base in order to prevent rotation of the holder plate relative to the mount base.

26. A table saw comprising the combination of the riving knife and the mounting device as in claim 18 and further comprising a table for placing thereon a workpiece, a cutting blade for cutting the workpiece, and a motor for driving the cutting blade, so that the workpiece is cut by the cutting blade as the workpiece is moved along the table, and

wherein the cutting blade, the motor and the mounting device are mounted to the mount, so that the riving knife is positioned on the rear side of the cutting blade substantially within the same plane as the cutting blade, and an upper portion of the cutting blade and an upper portion of the riving knife extend upward above the table.

39. The riving knife as in claim 20,

wherein the first knife portion is positioned further from the cutting blade than the second knife portion, and further comprising a cover vertically pivotally mounted to the first knife potion in order to cover an uncover the cutting blade.

27. A riving knife for entering a split formed in a workpiece by a cutting blade of a table saw during a cutting operation, comprising:

a first knife portion and a second knife portion separated from each other and arranged and constructed to be mounted the table saw and to be positioned adjacent each other to form the knife when mounted to the table saw,

wherein the first knife portion and the second knife portion respectively have a first edge and a second edge opposing to each other when the first knife portion and the second knife portion are mounted to the table saw, and

a positioning device arranged and constructed to position the first knife portion and the second knife portion within substantially the same plate.

28. The riving knife as in claim 27,

wherein the positioning device comprises a projection formed on the first edge of the first knife portion and a recess formed in the second edge of the second knife potion, so that the projection and the recess engages with each other to prevent the first knife potion and the second knife portion from moving relative to each other in a direction of thickness.

29. The riving knife as in claim 28,

wherein the projection extends along the length of the first edge and has a substantially V-shaped cross section;

and

wherein the recess extends along the length of the second edge and has a substantially V-shaped cross section conforming to the cross section of the projection.

30. The riving knife as in claim 27,

wherein the positioning device comprises a positioning member arranged and constructed to extend between and along surfaces of the first knife portion and the second knife portion.

31. The riving knife as in claim 30,

wherein the positioning member is movable relative to the first and second knife portions not to interfere with the movement of the workpiece along a table of the table saw during the cutting operation.

32. The riving knife as in claim 31,

wherein the positioning member is forced move by a part of the workpiece as the workpiece is moved during the cutting operation.

33. The riving knife as in claim 32,

wherein the positioning member is pivotally mounted to one of the first and second knife portions, so that the positioning member pivots within a plane substantially parallel to the surface of the fist and second knife portions.

34. The riving knife as in claim 33, further comprising a biasing member arranged and constructed to bias the positioning member in order to hold the positioning member in a first position,

wherein the positioning member pivots from the first position to a second position against the biasing force of the biasing member as the positioning member is forced to move by the part of the workpiece.

35. The riving knife as in claim 34,

wherein the positioning member has a pivotal axis positioned below the table,

wherein the positioning member extends substantially vertically upward from the pivotal axis in the first position, and

wherein the positioning member is positioned below the table when the positioning member is in the second position.

36. The riving knife as in claim 34,

wherein the fist knife portion has an upper portion extending upward beyond the height of the cutting blade,

wherein the positioning member is pivotally mounted to the upper portion of the first knife portion and extends substantially vertically downward therefrom,

wherein the positioning member is positioned above the workpiece when the positioning member is in the second position.

37. The riving knife as in claim 36,

wherein the first knife portion is positioned further from the cutting blade than the second knife portion.

38. The riving knife as in claim 37, further comprising a cover vertically pivotally mounted to the upper portion of the first knife portion in order to cover and uncover the cutting blade.