LAWN MOWER BLADE LEVELING DEVICE

A blade balancing device comprises a base member including an upwardly extending pin and a hollow cone configured to rest on the pin of the base member. The hollow cone includes a leveling element disposed at an apex thereof. The leveling element is configured to provide visual indication of a tilt of a lawnmower blade disposed on the hollow cone relative to a gravity direction.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to the field of lawn mower blade leveling devices, and more specifically to a lawn mower blade leveling device including a bubble level feature.

2. Description of Related Art

It is common for a blade of a lawn mower to periodically be sharpened in response to the blade becoming dulled or otherwise damaged following operational use thereof. It is important that the blade be sharpened in a manner that maintains an equal weight distribution relative to a central rotational axis thereof in order to appropriately balance the blade when installed to the associated mower. An imbalance of the blade is preferably avoided as such an imbalance can lead to an increased wear on rotational components of the mower and an increased degree of vibration present within the mower each of which contributes to shortening an effective life of the lawn mower. Aside from the lawnmower, an imbalance in the blade can result in increased stress and user fatigue as well as create potentially dangerous situations.

Blade balancing devices of the prior art typically include a cone-shaped blade balancer disposed on a pin extending upward from a base member. The blade balancer typically includes at least one circular ledge formed thereon for supporting and locating a central mounting hole of the blade. The blade balancer further includes a cone-shaped hollow interior defined by an inner wall that is inwardly tapered to a pointed end. A pointed end of the pin extends into a hollow interir of the blade balancer and engages the pointed end of the hollow interior. The interface of the pointed end of the pin and the pointed end of the hollow interior of the blade balancer accordingly allows the blade balancer to tilt in any direction relative to the pointed end of the pin. As such, when a blade is placed on the blade balancer a weight distribution of the blade can be determined by comparing the tilt of the blade balancer relative to the stationary base member from which the pointed pin extends. Such a blade balancing device is disclosed by U.S. Pat. No. 2,803,964 to Smith, which is hereby incorporated herein by reference in its entirety.

This method of relying solely on a visual relationship between the blade balancer and the base member presents several concerns. In some instances it is impossible to determine if the blade balancer is tilted relative to the base member due to the base member itself being tilted with respect to a gravity direction. For example, if the base member is disposed on a non-level surface it is possible that the user of the device will improperly determine that the blade is balanced by referring only to the relationship between the blade balancer and the base member. In other instances, many users of such a blade balancing device exclusively reference a visual tilt of the lawn mower blade resting on the blade balancer relative to background features present within a view of the user, such as adjacent table tops, wall edges, and the like. If such features are not arranged perpendicular to the gravity direction the user can improperly determine that the blade is balanced by improperly comparing a tilt of the blade relative to a non-level background feature. Additionally, defects present within the base member or the blade balancer may further alter a visual appearance of the tilt of the blade balancer relative to the base member.

It would therefore be desirable to produce a blade balancing device providing a secondary method of determining if a blade is balanced thereon with respect to the gravity direction.

Based on the foregoing, there is a need in the art for a blade balancer that will allow for the precise weight distribution measurement necessary to properly maintain blades. Such precise measurement requires a device and system having an omnidirectional balance capabilities as opposed to the current state of the art allowing only for a linear balancing without any precise measurement capability.

SUMMARY OF THE INVENTION

Compatible and attuned with the present invention, a device for determining a tilt of a lawn mower blade relative to a gravity direction has surprisingly been discovered.

In an embodiment, a blade balancing system comprises a base member having a pin extending upward from a central axis of the base member; a hollow cone having an interior apex and an exterior apex, wherein the pin pivotally engages the interior apex of the hollow cone, and wherein the hollow cone engages one or more apertures of a blade; and a leveling element in communication with the exterior apex, wherein the leveling element comprises a visual indicator, wherein the visual indicator provides indication of a tilt of the blade relative to a gravity direction when the blade is engaged with the hollow cone, and wherein a user modifies the blade based on the indication from the leveling element.

In an embodiment, the leveling element is cylindrical, and wherein the visual indicator comprises a fluid chamber having a gas bubble disposed therein.

In an embodiment, the visual indicator is a light or color indicator.

In an embodiment, the user modifies the blade through a method comprising the steps of: the user placing the base member on a surface, wherein the base member is placed on a surface with the pin extending upward relative to the base and the surface; the user placing the hollow cone onto the pin, wherein the pin matingly engages an interior of the hollow cone; zeroing out the hollow cone, wherein the user allows the hollow cone to rest on the pin, wherein the hollow cone is at zero when the visual indicator is coaxially aligned with the pin; the user placing a blade over the exterior apex of the hollow cone, wherein the blade comprises an aperture at a midsection of the blade; the user inspecting the visual indicator, wherein the visual indicator is either axially aligned with the pin and interior apex or the visual indicator is not coaxially aligned with the pin and the interior apex, and if the visual indicator is not coaxially aligned, the method further comprises the steps of: the user removing material from a side of the blade identified as out of balance. Then the user re-inspects the visual indicator, wherein if the visual indicator is at zero, the user replaces the blade onto a lawnmower.

In an embodiment of the invention, a blade balancing device comprises a base member including an upwardly extending pin and a hollow cone configured to rest on the pin of the base member. The hollow cone includes a leveling element disposed at, onto, or within an apex thereof. The leveling element is configured to provide visual indication of a tilt of the hollow cone relative to a gravity direction.

A method of using a blade balancing device is also disclosed. The method comprises the steps of providing a base member including an upwardly extending pin and a hollow cone configured to rest on the pin of the base member, the hollow cone including a leveling element disposed onto, at, or within an apex thereof, the leveling element configured to provide visual indication of a tilt of the hollow cone relative to a gravity direction; and determining a condition of the leveling element to determine if the hollow cone is tilted relative to the gravity direction.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the present invention and their advantages may be understood by referring toFIGS. 1-7, wherein like reference numerals refer to like elements.

FIGS. 1-6illustrate a blade balancing device1according to one embodiment of the invention. The blade balancing device1comprises a base member10and a hollow cone16. The base member10includes a substantially planar lower surface12and a tapered outer surface13. The lower surface12is substantially circular in shape and the outer surface13has a shape of a frustum. The base member10further includes a pin11extending upwardly from a central portion thereof. The pin11may be further surrounded by an annular hollow opening14of the base member10. The pin11extends upwardly until terminating at a pointed tip15.

The hollow cone16includes a substantially cone-shaped outer surface28and a substantially cone-shaped hollow interior30. The outer surface28of the hollow cone16further includes a plurality of annularly extending circumferential grooves17and horizontal shelves18. The horizontal shelves18form a seating surface for supporting a blade of a lawnmower. Each of the circumferential grooves17forms a vertical surface19corresponding to one of the horizontal shelves18. Each of the vertical surfaces19has an outer diameter selected to correspond to an inner diameter of a central opening of a correspondingly dimensioned blade. In some embodiments, each of the vertical surfaces19has an outer diameter corresponding to a central opening of a blade having an inner diameter. The diameter may be measurable through any standard of measurement including but not limited to U.S. standards or the metric system standards. In other embodiments, each of the vertical surfaces19has an outer diameter corresponding to a central opening of a blade having an inner diameter measured in standard metric unit dimensions. In a preferred embodiment, a combination of a plurality of vertical surfaces19having an outer diameter and a plurality of vertical surfaces19having an outer diameter measured in metric unit dimensions is utilized, thereby advantageously allowing a single hollow cone16to accommodate lawnmower blades. As such, the alternating pattern of the horizontal shelves18and the vertical surfaces19allows for a variety of different blades having central openings with differing inner diameters to be suitable for balancing on the blade balancing device1.

As shown inFIGS. 1-6, a lower most portion25of the hollow cone16is spaced apart from an uppermost portion26of the outer surface13of the base member10when the hollow cone16is supported on the pointed tip15of the base member10. Additionally, the outer surface13of the base member10is arranged substantially parallel to the outer surface of the hollow cone16about a circumference of each of the base member10and the hollow cone16, causing the base member10and the hollow cone16to cooperate to be substantially cone-shaped in appearance.

The hollow cone16includes a leveling element40disposed on the outer surface28of the hollow cone16at an apex thereof. The leveling element40is configured to provide a visual indication of a tilt of the hollow cone16relative to a gravity direction. The leveling element40maybe substantially cylindrical in shape including an outer circumferential surface41and a substantially planar upper surface42. The leveling element40includes a substantially cylindrical fluid chamber43filled at least partially with a first fluid. A portion of the fluid chamber43is devoid of the first fluid to form a gas bubble44within the fluid chamber43.

As shown inFIGS. 4-6, the upper surface42of the leveling element40includes at least one visual indicia45formed thereon. The visual indicia45may be substantially circular in shape and may be centered on the upper surface42of the leveling element40. At least a portion of the upper surface42of the leveling element40is transparent to allow a user to visually identify a position of the gas bubble44relative to the visual indicia45when the gas bubble44translates within the fluid chamber43of the leveling element40.

In use, the hollow cone16is disposed on the pin11of the base member10, The point contact between the pointed tip15of the pin11and an inner surface of the hollow cone16allows for the hollow cone16to attain a balanced state relative to the gravity direction. Once the hollow cone16is positioned on the base member10the central opening of the blade is then placed over the properly dimensioned vertical surface19of the hollow cone16to position the blade on a corresponding horizontal shelf18of the hollow cone16. When in this position a variation of a mass of any side of the blade relative to the central opening will result in the blade and therefore hollow cone16being tilted relative to the base member10. The user can then determine if the blade is balanced by checking each of a tilt of the lowermost portion25of the hollow cone16relative to the uppermost portion26of the outer surface13of the base member10, a tilt of the blade itself relative to a horizontally extending reference line present within view of the user, and a position of the gas bubble44relative to the visual indicia45. As explained herein above, mere reference to a tilt of the hollow cone16or the blade itself can lead to an improper determination of the tilt of the blade due to several factors. Accordingly, the leveling device40prevents such an occurrence of an improper determination of the tilt of the blade by providing an indication of a tilt of the blade relative to the gravity direction that is independent of a visual appearance of the blade relative to the visible surroundings.

As should be understood, a position of the gas bubble44relative to the visual indicia45will change as a result of a buoyancy force acting on the gas bubble44causing the gas bubble to move towards an uppermost position within the fluid chamber43relative to the gravity direction. When the upper surface42of the leveling element40is arranged perpendicular to the gravity direction the gas bubble44is caused to move to a central position relative to the visual indicia45due to a pressure equalization of the fluid surrounding the gas bubble44when in this configuration.

The leveling element40accordingly aids the user in confirming that the blade is balanced relative to the gravity direction by allowing the user to determine if the lower surface12of the base member10is also disposed on a level surface by checking the position of the gas bubble44. This feature therefore prevents an incidence of an imbalanced blade resulting from the user misidentifying a tilt of the hollow cone16relative to the base member10, the user attempting to balance the blade on a surface that itself is not level, or the user improperly referencing surrounding surfaces relative to the blade that are themselves not level.

Referring now toFIG. 7, a blade balancing device101according to another embodiment of the invention is disclosed. The blade balancing device101is substantially similar to the blade balancing device1ofFIGS. 1-6and includes a hollow cone116, a base member110, a plurality of horizontal shelves118, a plurality of vertical surfaces119, and a leveling element140. The blade balancing device101differs from the blade balancing device1in that the leveling element140is received or molded into a substantially cylindrical opening150formed adjacent an apex of the hollow cone116. Accordingly, a least a portion of an outer surface128of the hollow cone116annularly surrounds the leveling element140. This arrangement of the leveling element140being disposed or molded within a portion of the hollow cone116itself rather than being disposed directly on an uppermost surface of the hollow cone116advantageously prevents an incidence of the leveling element140being damaged or displaced from the remainder of the hollow cone116. Furthermore, the outer surface128of the hollow cone116may be formed to be substantially opaque to encourage a user of the leveling element140to determine a position of a gas bubble144formed therein from a substantially vertical direction, thereby ensuring that assumptions regarding a position of the gas bubble144from a non-perpendicular direction are avoided.

The blade balancing device101illustrated inFIG. 7further includes a base leveling element160. The base leveling element160is configured to provide a user of the blade balancing device101a visual indication of a tilt of the base member110relative to the gravity direction. The base leveling element160may be substantially cylindrical in shape and may include a single gas bubble162configured to indicate a tilt of the base leveling element160. This added form of leveling device aids the user in confirming that the surface on which the base member110is disposed is itself level, thereby preventing an incidence of an improperly determined tilt of a blade.

In an alternative embodiment, the blade balancing device has a base where a pin extends upward from a central axis of the base. The leveling element separate frustaconical shaped structure wherein the exterior surface is smooth, textured, or stepped to allow for proper seating of a blade placed thereon. The distal point of the pin engages an interior apex of the frusticonical structure wherein the apex is coaxially aligned with the pin and the central axis of the base. The exterior apex of the frusticonical leveling element is opposite of the interior apex. The leveling element with the gas bubble is affixed to the exterior apex. The attachment between the gas bubble leveling device and the exterior apex is either permanent wherein the leveling element is integrated into the exterior apex, or within the exterior apex. The leveling element may also be removeable attached whereby the leveling element and the exterior apex comprise corresponding magnets for attraction, a friction attachment, or a hook and loop attachment. In yet another embodiment, the leveling element operates without a gas bubble where the leveling element has a visual indicator such as a color or a light to indicate a true level relative to the weight distribution of the blade.