Patent Application
20080209881
Conventional metal lawnmower blades are prone to problems related to human injury, property damage, lawnmower maintenance, air pollution, fuel economy, and the inherent requirement for second-operation edge trimming around sidewalks and trees and such.
The Bauer Blade uses a flexible cutting material as its “blade” that will not penetrate shoes or work gloves. Thus, the invention protects against direct blade injury.
The flexible blade material of the Bauer Blade is many times lighter than the blade material of a conventional lawnmower blade. This greatly reduces momentum transfer from the blade to objects in the lawn. Objects in the lawn include intended targets such as vegetation as well as unintended targets such as debris located in the lawn. When a conventional lawnmower blade strikes a debris object, the blade typically knocks the object into motion at a high rate of speed. This activity frequently results in projectiles shooting out from the lawnmower which can cause significant human injury and property damage. The Bauer Blade, conversely, does not initiate large enough momentum transfer to produce high-speed dangerous projectiles. Consequently, the Bauer Blade significantly reduces the production of dangerous projectiles and the injuries resulting therefrom. These two safety factors alone, protection from direct blade injury and from indirect blade or projectile injury, provide very significant advantages over conventional lawnmower blades.
Maintenance is another advantage. Conventional lawnmower blades require sharpening, which typically requires removal of the blade from the lawnmower, drop-off time at a sharpening service provider, and then reinstallation of the blade. Sharpening is necessitated by normal wear from cutting vegetation or by collision with foreign objects. The Bauer Blade never needs sharpening. Unlike conventional lawnmower blades, the Bauer Blade typically can be “renewed” in less than five minutes, without tools or downtime. Renewal is required annually or more typically biannually, depending on frequency of use, toughness of the vegetation, and toughness of the particular flexible cutting material used in the Bauer Blade. Renewal is the replacement of worn flexible cutting material with new flexible cutting material.
Conventional lawnmower blades cause damage to uneven ground, tree roots, garden hoses, sprinkler heads, and other valuable. The Bauer Blade will not damage these items because the flexible cutting material skims right over them without scalping.
Moreover, the shape of the Bauer Blade has advantages over the shape of conventional lawnmower blades. The Bauer Blade is essentially a large disc that does not readily transfer momentum to targets in the lawn and therefore does not incur large drag forces during rotation. This behavior is summed up by the application of Newton's third law to the particular dynamics at hand—large momentum transfer from conventional blade to targets yields large drag forces on the conventional blade, conversely, small momentum transfer from Bauer Blade to targets yields small drag forces on Bauer Blade. The Bauer Blade experiences drag primarily only from its lightweight flexible cutting material passing through the target area. A conventional blade, on the other hand, is essentially two heavy rigid spinning knives that incur drag forces across the full length of the structure.
Also, the cutting portions of conventional blades are extremely heavy as compared to the weight of the vegetation for which the blade is used to cut. This enormous weight difference is not required for successful cutting and is, in fact, detrimental to safety, property damage, maintenance, air pollution, and fuel economy of the mower because of the large degree of momentum transfer between the blade and its targets.
The net result is that conventional metal lawnmower blades require significantly more energy to keep in rotational motion. The Bauer Blade, on the other hand, uses much less energy to sustain rotation. Since current technology of battery powered lawnmowers is less than optimal for want of longer battery life, the Bauer Mower would likely improve technology in this area as its use would yield longer battery life.
The invention 10 can serve as a replacement blade for a conventional lawnmower blade on a standard one-blade lawnmower or multi-blade mowers such as riding lawnmowers or wide-cutting walk behind mowers.
The preferred embodiment of the invention is depicted in
The preferred embodiment of the flexible cutting material attachment means is depicted in
Another flexible cutting material attachment means is depicted in
Another flexible cutting material attachment means is depicted in
Another flexible cutting material attachment means is depicted in
The one-piece molded, casted, machined, or stamped disc 20 needs to be balanced to insure proper rotation at the typical rotations-per-minute of lawnmower motors without wobbling or unsteady rotation. Balancing may also require the one-piece molded, casted, machined, or stamped disc 20 to have similar overall weight to that of the conventional metal blade for which the invention is to replace. This requirement could translate into sizing requirements for the Bauer Blade. One-piece molded, casted, machined, or stamped discs 20 should have an Overall Disc Radius 60 of 40-60% of the “internal blade cavity radius” measurement. The “internal blade cavity radius” measurement is specific to a particular lawnmower model and is defined as distance between the center-line of the blade shaft 100 to the inside diameter of the mower housing or, in the case of multi-blade mowers, the distance between the center-line of blade shaft 100 to the outer diameter of the next closest adjacent blade. An overall disc radius 60 of essentially one half the internal blade cavity radius measurements is the preferred embodiment. Thus, with the preferred embodiment, the flexible cutting material 30 length would also equal essentially half of the internal blade cavity radius measurement. With the preferred embodiment, the distance between the center-line of the blade shaft 100 and inside diameter of the mower housing should essentially be divided into two equal sections: half disc and half flexible cutting material. The same proportions should be used when fitting multi-blade mowers with the preferred embodiment of the Bauer Blade, i.e. the distance between the blade shaft center-line 100 and the outer diameter of the next closest adjacent blade should essentially be half disc and half flexible cutting material.
When renewing the flexible cutting material 30, one need only add new flexible cutting material 30 with excess length and the Bauer Blade will self-correct the length of flexible cutting material 30 by wearing away excess flexible cutting material 30 against the mower housing. This technique should also be applied when renewing flexible cutting material on multi-blade lawnmowers. In this case, the length of flexible cutting material 30 self-corrects against the flexible cutting material 30 on the next closest adjacent Bauer Blade and vice versa.
Despite that only round cross-sectional flexible cutting material 30 is depicted in the drawings, the flexible cutting material 30 of the Bauer Blade may be of a non-round cross-sectional geometric shape to provide more efficient vegetation cutting. The preferred embodiment of the invention is a round cross-sectional shape because round cutting line is readily available and is extremely cost effective.
As depicted in
As with most conventional lawn mowers, the Bauer Mower 140 has a lawnmower blade cavity housing which protects people from flying debris kicked up by the lawn mower blade. Typically, a lawnmower blade cavity housing has but two openings: i) one at the bottom of the housing, through which the blade may have access to vegetation to cut and ii) another on the side of the housing, through which to expel cut vegetation from the blade cavity housing. The Bauer Mower 140 has these two openings in the lawnmower blade cavity housing. Additionally, the Bauer Mower 140 has a third opening in the lawnmower blade cavity housing, defined as the trimming opening 130. The trimming opening 130 is located on the upper portion of the lawnmower blade cavity housing 110.
The trimming opening 130 exposes the Bauer Blade 10 and, more specifically, the flexible cutting material 30 to area outside of the lawnmower blade cavity housing. This “flexible cutting material exposed” area or trimming opening 130 may be used to trim around trees, curbing, sidewalks, driveways, and other items. The trimming opening 130 could be maneuvered carefully, in a manner similar to the movement of a conventional weed-whacker string edge trimmer, around these items, yielding a mowed and trimmed lawn without second operation.
As discussed, the Bauer Blade 10 has lower drag forces than those associated with conventional lawnmower blades. Consequently, a Bauer Mower 140, equipped with a Bauer Blade 10, requires less energy to operate. Given the current technology of battery powered lawnmowers, the Bauer Mower 140 may likely be much better suited for clean electric/battery power than standard lawnmowers with conventional metal blades.
Although
The instant application is a continuation of U.S. application Ser. No. 11/308,932 entitled “The Bauer Blade” filed on May 26, 2006 and claims the benefit of such application.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11308932 | May 2006 | US |
| Child | 12053737 | US |
