Patent Application
20190091825
This invention pertains to a device for sharpening blades, particularly blades for residential and commercial lawn mowers, sod cutters, and the like. The blade sharpener of the present invention provides a rotatable blade bed that that can quickly be adjusted over a range of different sharpening angles, which allows greater efficiency in sharpening multiple blades of varying honing angles. The blade sharpener of the present invention is also adapted for honing both right-side and left-side blades with only a simple adjustment to the blade bed base and the grinder yoke.
There are numerous examples of blade grinders in the prior art. However, there is not a sharpening device that can quickly and easily accommodate a variety of blade sharpening angles while also allowing easy adaption between right and left-sided blades. The advantage of the present invention is that one single sharpening device can now be used across a wide range of residential and commercial cutting blades without the need for time-consuming refitting and jury-rigging of the sharpening device.
Prior art devices generally combine rotational sharpening functions around a single point. This is an impractical approach to repetitive sharpening operations of differing blades because, the device is generally unwieldy to adjust due to the difficulty of isolating one axis for rotational adjustment while the other axes are moving. In addition, prior art devices fail to accommodate for right and left-side blade interoperability with blades of varying honing angles. For example, in U.S. Pat. No. 9,102,031, issued to Page, a sharpening device is disclosed that suffers from these disadvantages. The Page device has a 3-way pivot point located above an unmoving blade bed. The device is inadequate for repetitive sharpening of blades with varying honing angles because of the difficulty in adjusting the rotational attack of the grinder relative to the honing surface of the blade. Further, the device does not easily operate between set angles of grinding, which is a necessary feature for efficient blade sharpening operations. In addition, the immovable blade bed of Page cannot accommodate both right and left-sided blades.
Other prior art devices suffer similar disadvantages. U.S. Pat. No. 7,967,666 to Messner discloses a blade sharpening apparatus with a pivot connector where the grinder itself is rotated around an axis perpendicular to the blade length. The Messner device also allows translational movement along the blade length but it does not allow for easy relocation of the grinder away from the blade surface for the purpose of interchanging blades. Further, the Messner device is unable to easily accommodate both right and left-sided blades.
U.S. Pat. No. 7,918,715 to Clark et al. discloses a device that can sharpen both clockwise and counterclockwise blades (right and left-sided blades) by rotating the blade bed a full 180 degrees. However, the blade bed is not otherwise adjustable for accepting blades of various hone angles. In order to process blades of varying angles, an operator of the Clark device must make careful adjustments to the attack angle of the grinder. Again, this is a cumbersome approach for repetitive sharpening operations.
U.S. Pat. No. 6,761,623 to Baker discloses a blade sharpening device that sharpens blades at a predetermined angle. The Baker device has a means of blade support that allows for the proper positioning of the blade with respect to the sharpening mechanism so as to generate the correct sharpening angle for the sharpening of the blade. However, the device cannot accommodate the simple interchange of right and left-sided blades. Furthermore, adjustment of the honing angle is cumbersome, with a hand operated crank set forth as the preferred method for rotating the blade bed. The Baker invention does not provide for rapid adjustment of blade angles as now provided by the present invention.
It is a feature of the present invention to provide a blade sharpener that can accommodate rapid and easy adjustment of the sharpening angle through an easily adjustable blade bed.
It is still another feature of the present invention to provide a blade sharpener that has a grinding apparatus that is freely moveable in a wide range of motion while locking the attack grinding angle.
It is still another feature of the present invention to provide a blade sharpener that can easily be switched between right and left-sided blades.
It is yet another feature of the present invention to provide a blade sharpener that allows for safe operation of the grinding apparatus during both right and left-sided sharpening operations.
It is yet another feature of the present invention to provide a blade sharpener that supports quick, repetitive sharpening of blades with varying honing angles.
It is still another feature of the present invention to provide a blade sharpener that is suitable for commercial operations.
It will be appreciated that the drawings are illustrative and not limiting of the scope of the invention which is defined by the appended claims. The embodiments shown accomplish various aspects and objects of the invention. It is appreciated that it is not possible to clearly show each element and aspect of the invention in a single figure, and as such, multiple figures are presented to separately illustrate the various details of the invention in greater clarity.
Reference will now be made in detail to the presently preferred embodiments of the invention. There are also representative examples of the invention illustrated in the accompanying drawings. Throughout the following detailed description, the same reference numeral refers to the same elements in all figures.
Now referring to the drawings, and first to
The blade sharpener of the present invention further comprises blade bed assembly 20, that holds the mower blade in a position for sharpening. The assembly comprises blade bed base 22 and blade bed 23. As shown in
A holding clamp 25 which is rotatable is affixed to blade bed 23 for securely holding blade 60. Holding clamp 25 can be any type of device that can secure blade 60 so that it does not shift or move during the sharpening procedure. In one embodiment, holding clamp 25 is a vice-type clamp that can be locked into holding position and easily released into an unlocked position when desired. Studs 26 are affixed to blade bed 23 to provide support to blade 60 and to prevent downward movement of blade 60 during the sharpening operation. Blade bed 23 also is provided with shoulder bolt holes 28 for receiving shoulder bolts 27. As shown in
As discussed above, the present invention provides for easy switching between right and left-sided blades. The dual sets of shoulder bolt holes 28 and the placement of studs 26 on opposite ends of blade bed 23 provide a mirrored configuration such that blade bed 23 can be repositioned 180°. Referring to
The blade sharpener of the present invention further comprises flex arm 30, which is a parallel arm assembly. Gas springs 32 are placed in each arm segment so that flex arm 30 can be extended and held in position without need for counter weights or counter-balancing springs. Flex arm 30 is attached to post 14 using swivel mount 34, which allows a wide range of rotational motion around the axis of rotation defined by the longitudinal length of post 14. The free rotation enabled by flex arm 30 and swivel mount 34 allow operation of the grinder 40 in a wide range of motion and is particularly helpful for quickly moving grinder 40 out of the way while exchanging blades for sharpening. In addition, a particular feature of the present invention, is the limitation of movement of grinder 40 to two dimensions in relation to blade 60. Because the angle of grinding attack is set by the rotational movement of blade bed 23 through adjusting ratchet arm 24 and not through rotational movement of flex arm 30 in a third dimension, the present grinder is better suited to discrete changes of grinding attack. Ratchet arm 24 is located near the grinding operation to enable the operator to conveniently adjust the grinding attack. Further, isolating the grinding attack adjustment mechanism away from the movement of flex arm 30 is safer for the operator. When the operator wishes to adjust the grinding angle, he can swing flex arm 30 out of the way and easily adjust ratchet arm 24 to rotate blade bed 23 without exposing skin, clothing or other loose items to the spinning grinder blade 42. Prior art arrangements where the grinding attack adjustment mechanism is associated with the swing arm or the grinder itself are unsafe because the operator is more exposed to the spinning grinder when adjusting the attack angle.
As mentioned above, the present invention also comprises a grinder 40 for sharpening blade 60. Grinder 40 comprises grinding blade 42, body 44, handle 46, and safety guard 47. Grinding blade 42 may be an abrasive disk or a beveled plate-type surface that offers an incremental approach to the grinding action. Body 44 houses the motor of grinder 40, and also provides a general surface for moving or holding the grinder in position. In addition, handle 46 provide an additional gripping location for guiding and moving the grinder through its range of motion. Handle 46 is bolted through body 44 of grinder 40 and is secured in place with a nut (not shown) located on the opposite side of the body. Safety guard 47 is placed over one half of grinding blade 42 in a direction opposite honing edge 62 of blade 60. The safety guard prevents loose items and skin from inadvertent contact with grinding blade 42. It also catches grinding debris from spinning grinding blade 42 and directs it down and away from the operator. Grinder 40 also comprises face tabs 48 on a top portion of the grinder that assist in holding grinder 40 in a steady position in yoke 50, as explained below.
The present invention further comprises a yoke 50 for attaching grinder 40 to flex arm 30. As shown in
During operation of the blade sharpener on a right-handed blade, the operator can set blade bed 23 at a 15° angle away from the line formed along the length of flex arm 30. In this manner, the operator can easily see grinding blade 42 acting on honing edge 62 of blade 60. To switch to a left-handed blade, the operator simply moves blade bed assembly 20 by 180° to an opposite position, places the blade on the opposite end of the now swiveled blade bed assembly and adjusts the grinder 40 angle using set screw 52 to an opposite 15° angle away from the line formed along the length of flex arm 30. This allows grinding operations to continue without needing to remove safety guard 47. Without adjusting the angle of grinder 40 from its right-sided position, safety guard 47 would interfere with the sharpening action on left-sided blades. Thus, the present invention provides for multi-sided blade honing without needing to disable or remove safety guard 47.
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
| Number | Date | Country | |
|---|---|---|---|
| 62564511 | Sep 2017 | US |
