In-situ blade sharpener

Abstract

A blade sharpening device easily connectable to a source of rotating power, such as a battery powered hand drill, and having a housing, a selectably locatable pitch adjuster and a clamping mechanism means for maintaining the housing and grinding surfaces of the sharpening device at a desired grinding angle. The housing extends completely over the width of the rotatable drums wrapped with grinding surface. By clamping the device directly to the blade and stabilizing the device in this position, the operator has greater control and stability of the sharpener when in use on, for example, a lawn mower blade which is still attached to the lawn mower drive shaft at the underside of the lawn mower housing. This on-site, in-place blade sharpening capability eliminates the necessity of removing the blade for its sharpening, while still allowing easy and safe sharpening of the blade.

Description

CROSS REFERNCE TO RELATED APPLICATION [0001] Not Applicable STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not Applicable BACKGROUND OF THE INVENTION [0003] The present invention is directed to blade sharpening devices in general and more particularly to blade sharpening devices suitable for on-site, in-place use on blades which are, for example, attached to a driving member, such as, for example, a lawn mower blade, and even more particularly to such a device which has a safety guard and associated means for allowing the operator to manually control the positioning and movement of the sharpening device. In additional to the preferred, exemplary application of lawn mower blades, the device can be used to sharpen other devices, such as, for further example, garden tillers, shovels, hoes, as well as scythes, cane knives, sweepers, bladed “weed eaters”, bush hogs, etc. [0004] It is often the case with a mechanically powered blade, such as the blade of a conventi...

AI Technical Summary

Benefits of technology

[0017] It is thus an object of the present invention to provide a portable blade sharpening device for lawn mowers and the like which has a housing which will contain the rotating sharpening segment protecting the operator from projectiles created during the sharpening process and the grinding surface as it moves along the blade. The housing also provides a gripping surface for the operator to hold the sharpening device in position while clamping the device to the blade enabling the operator to have free hands once the device is in the clamped position while the blade is still in place in its working position on the lawn mower or like machine. The grinding surface shall be slidably mounted to an extension rod allowing for the sharpening segment to move along the entire length of the area of the blade that is to be sharpened without have to loosen the clamps or remove the entire housing from the blade.

[0018] It is another object of the present invention to provide a blade sharpening device which will increase the operator's control of and accuracy in the positioning of the grinding surface of the sharpening device on the blade during the sharpening process and does not require it to be braced against any part of the housing of the lawn mower or other such structural parts or machinery except for the blade itself so this device could be used on various sizes, models, and configurations of lawnmowers or other devices that utilize a blade. The present invention provides a method of sharpening an edge of the blade of a lawn mower while it is still attached to a drive member. This enables the operator to save time and energy by not having to remove the blade and place it in a separate detached clamp or vice.

[0019] Accordingly, the present invention in its preferred embodiment is directed to a blade sharpening device including a housing preferably with top, side, and bottom surfaces which extend over the complete axial width and cover over all of the rotating sharpening segment. The housing not only protects the operator from flying debris or fragments but also provides a safe area for the operator to grasp in several different ways in manipulating the device to secure it to the lawn mower blade. Additionally, a selectively located drive shaft, clamp tightening lever and sharpening segment pitch adjuster, each having a multiplicity of possible positions or locations preferably is also included, further adding to the ease of control and positioning of the device.

[0021] In use, the operator inserts the edge of the blade that needs to be sharpened through a receiving means in the housing and secures the clamp onto the blade which causes the whole sharpening device to be affixed securely to the lawn mower blade still attached to the body of the mower. The operator can adjust the angle of the grinding surface with the pitch adjuster. The operator then uses the drill to rotate the drum to which the drill is attached which causes the grinding surface to rotate freely within the housing of the sharpening device. The operator can re-position the pitch and the blade that is clamped within the housing to maximize the sharpening capability. The use can also manual slide the grinding member along the shaft and across the blade, or a threaded screw-shank mechanism can mechanically cause this action to occur.

[0022] The present invention thus provides an on-site, in-place, portable blade sharpening device for lawn mower blades and the like, preferably using the standard type portable electric hand drill for power, which device is hand-manipulated, adaptable for use with many different lawn mower designs, as well as many other devices, relatively safe in use, and easily, stably and accurately aligned and positioned by the operator using an easily maneuverable clamping device and pitch adjuster that allows the operator to only hold the apparatus that is attached to the shank member to cause the rotation of the drum. This allows the operator to have free use of his other hand during the sharpening process. In addition to the particular application of lawn mower blades, the device of the invention can be used to sharpen other devices that have a blade that has a surface large enough to be clamped and have a rotating grinding surface applied to the edge of the blade, such as, for further example, garden tillers, shovels, hoes, as well as scythes, cane knives, sweepers, bladed “weed eaters”, bush hogs, etc

Problems solved by technology

One problem with maintaining a sharp edge on such a blade is the inconvenience involved in removing the blade from its driving member in order to sharpen the blade on a blade sharpening device, such as, for example, a bench mounted grinding wheel.

However there remains problems with such devices due to, inter alia, problems of safety, the ability to monitor the edge sharpening while it is in progress, and accuracy in controlling the angle of the edge being ground since the operator is required to manually hold the device against the blade.

Such a device is very limited in its application being confined to use basically only with the lawn mower design illustrated and can be relatively dangerous to use, with the rotating grinder being exposed to the operator during use.

The device includes no guard for the rotating sharpening members, making it relatively dangerous, and no means are provided to allow the operator to grasp the device at both ends, making it more difficult to use and accurately position.

As above, this approach of direct bracing on the lawn mower structure greatly limits the applicability and use of the device.

Also, as above, the substantial exposure of the rotating sharpening device to the operator makes the device relatively dangerous to use.

Like Holland et al, the Kolling device includes no guard for the rotating sharpening member, making it relatively dangerous to use, and no means are provided to allow the operator to grasp the device at both ends, making it more difficult to use and accurately position.

This patent is not directly relevant to the field of the invention and does not help to overcome the deficiencies of the prior art discussed above and below.

Such an approach, in which the device rides through a guide plate 11 in flat-face-to-flat-face surface engagement with the underside of the blade and which does not use a multi-purpose electric drill but rather a contained, dedicated motor, is relatively inflexible in its use and relatively expensive.

It does not provide freedom of lateral or angular movement, nor the easily controllable and strongly grippable handle of a power drill, all of which can assist in the easy and accurate positioning of the rotating sharpening member on the blade.

The above mentioned inventions can be unsafe since the sharpening mechanisms are exposed and the operators hands are in close proximity to the blade as well as the sharpening surfaces that abrade the edge of the blade.

Furthermore, the manual process of holding the sharpening devices against the blade does not allow for uniform sharpening and may result in “kick-back” of the devices if a nick or dent is hit with the sharpening device.

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