FIELD OF THE INVENTION
The present invention relates to a machining grinder and particularly to a machining grinder equipped with a curved motion mechanism.
BACKGROUND OF THE INVENTION
Machining processes usually rely on a machining grinder to process various types machining tools such as gears, worms, drills, milling cutters, hobbing cutters and the like. Such a machining grinder mainly includes a cutting power mechanism, a cutting position adjustment mechanism and a feeding mechanism for an intended working piece. For processing the worms the commonly adopted approach is turning with a cutter.
U.S. patent application No. 20090241712 discloses a worm processing manner. It mainly clamps a working piece in a chuck first; next, forms an intended shaping portion at one end of the working piece by turning; then processes a primary helical teeth section on the intended shaping portion via two opposing shape-forming wheels; then clamps the working piece in a chuck and performs precise machining on the helical teeth section via a hobbing cutter inclined at 15 degrees against the axis of the working piece; the hobbing cutter and the working piece are spun at the same speed ratio, and the axes of the hobbing cutter and working piece are maintained at a constant distance to finish the product.
While processing the worm by turning can make the finished product in one process at a faster speed to facilitate mass production, there is still room for improvement in terms of precision.
SUMMARY OF THE INVENTION
The primary object of the present invention is to solve the problem of the conventional technique that processes the worms by turning and results in deficiency in precision.
To achieve the foregoing object the present invention provides a grinder equipped with a curved motion mechanism to process a working piece to form a double-envelope structure. The grinder of the invention includes a grinding wheel, a driving shaft, a track bracket and a holder. The grinding wheel includes a grinding edge which has a grinding zone in contact with the working piece. The driving shaft drives the grinding wheel spinning and has a fastening end connecting to the grinding wheel, a free end remote from the fastening end and a middle section between the fastening end and free end. The track bracket holds the driving shaft and is movable in a curved motion against the holder. The driving shaft is coupled with the track bracket via the middle section and driven by the curved motion and tilts against the holder to oscillate about the grinding zone of the grinding wheel as an oscillation center.
Through the curved motion of the track bracket against the holder the driving shaft is driven in the oscillation to process the working piece on the grinding zone at varying angles. Thus a worm can be formed with the double-envelope structure, and a multi-angle grinding process also is formed to improve process precision
The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an embodiment of the invention.
FIG. 2 is a schematic view of an embodiment of the invention showing the track bracket and holder in a coupled condition.
FIG. 3A is a schematic view of an embodiment of the invention showing a swivel movement.
FIG. 3B is a schematic view of an embodiment of the invention showing another swivel movement.
FIG. 4A is a schematic view of an embodiment of the invention showing a grinding condition.
FIG. 4B is a schematic view of an embodiment of the invention showing another grinding condition.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Please refer to FIG. 1 for an embodiment of the invention that is a grinder equipped with a curved motion mechanism to process a working piece 60 to form a double-envelope structure 61 (also referring to FIGS. 4A and 4B). The grinder of the invention includes a grinding wheel 10, a driving shaft 20, a track bracket 30 and a holder 40. The grinding wheel 10 has a grinding edge 11. In this embodiment the grinding edge 11 is an inclined surface, but this is not the limitation, and also can be formed in an arched surface protrusive radially. The grinding edge 11 has a grinding zone 111 in contact with the working piece 60. The driving shaft 20 drives the grinding wheel 10 spinning and has a fastening end 21 connecting to the grinding wheel 10, a free end 23 remote from the fastening end 21 and a middle section 22 between the fastening end 21 and free end 23.
Referring to FIG. 2, the track bracket 30 is coupled with the middle section 22 of the driving shaft 20, and has an indented upper curved track 31 and a lower curved track 32 opposing the upper curved track 31. The holder 40 has an upper latch 41 and a lower latch 42 to latch respectively the upper curved track 31 and lower curved track 32 so that the track bracket 30 is clamped onto the holder 40. The track bracket 30 further has an elongate gear rack 33 located on the upper curved track 31. The holder 40 has a transmission gear 43 engaged with the gear rack 33. The transmission gear 32 also is coupled on a motor 44. In this embodiment, the transmission gear 43 includes three sets driven by the motor 44.
Referring to FIG. 1 again, in this embodiment the grinder further includes a rotary seat 50 located at one side of the holder 40 remote from the track bracket 30 and hinged on the holder 40 so that the rotary seat 50 can swivel against the holder 40. More specifically, take three dimensional coordinates including X-axis, Y-axis and Z-axis as an example, the driving shaft 20 has a spinning axis 24 that can be in parallel with the Y-axis, then the grinding wheel 10 is parallel with a XZ plane formed by the X-axis and Z-axis. When the driving shaft 20 is moved by the curved motion the spinning axis 24 oscillates in parallel with the XY plane and drives the grinding wheel 10 to form an oscillation axis 25 extended from the grinding zone 111 as an axis. The oscillation axis 25 is parallel with the Z-axis. When the rotary seat 50 swivels against the holder 40, the holder 40 has a swivel axis extended to form a swivel axis 51 parallel with the X-axis, so that the swivel axis 51 swivels against the rotary seat 50. Also refer to FIGS. 3A and 3B for an embodiment of the invention in swivel conditions. In FIG. 3A, the holder 40 tilts against the rotary seat 50 during swiveling, and the spinning axis 24 and Y-axis form an included angle of negative 30 degrees. Referring to FIG. 3B, the holder 40 also tilts against the rotary seat 50 during swiveling, but with the spinning axis 24 and Y-axis forming an included angle of positive 30 degrees.
Please refer to FIGS. 4A and 4B for an embodiment of the invention in grinding conditions. When in use, the working piece 60 is held by a chuck 70 in contact with the grinding zone 111 to receive grinding. During grinding the motor 44 drives the transmission gear 43 which drives the gear rack 33 to move along the upper curved track 31 and lower curved track 32 against the holder 40, thereby the driving shaft 20 is driven and tilted against the holder 40 to oscillate about the grinding zone 111 as the oscillation center, hence the double-envelope structure can be formed on the working piece 60 by changing the contact angle with the working piece 60 without changing the contact position between the grinding zone 111 and working piece 60. It is to be noted that during oscillation the spinning axis 24 and the Y-axis are crossed to form an angle no greater than 30 degrees. When the spinning axis 24 and Y-axis are crossed at 30 degrees, the rotary seat 50 swivels against the holder 40 so that the swivel axis 51 and the XY plane are crossed at an angle no greater than 20 degrees.
As a conclusion, the invention, through the curved motion of the track bracket against the holder, can drive the driving shaft in oscillation to perform process on the working piece via the grinding zone at different angles to form a worm with the double-envelope structure. In addition, grinding precision improves. Moreover, with the rotary seat hinged on the holder, the grinding zone not only can oscillate horizontally at varying angles, also can swivel vertically increase angle alterations to achieve multi-angle grinding effect, thus is adaptable for grinding of diversified working pieces. It provides significant improvement over the conventional techniques.
While the preferred embodiment of the invention has been set forth for the purpose of disclosure, modifications of the disclosed embodiment of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.
Patent Application
20130237133
