Earth working – Lawn edger – With or convertible to non-earth working implement
Reexamination Certificate
2002-05-17
2004-02-17
Batson, Victor (Department: 3671)
Earth working
Lawn edger
With or convertible to non-earth working implement
C172S017000, C056S013700, C030SDIG005, C030S287000
Reexamination Certificate
active
06691792
ABSTRACT:
BACKGROUND OF THE INVENTION
RELATED APPLICATION
This application claims priority based upon my prior United Kingdom patent application, Serial No. GB 0112409.8, filed May 22, 2001.
1. Field of the Invention
The present invention relates generally to lawn care equipment and, more particularly, to lawn care equipment especially adapted for providing a clean cut lawn edge along hard surface.
2. Description of the Prior Art
String trimmer devices are well known in the art. Generally, a string trimmer device includes a motor, a handle, a drive shaft driven by the motor, a drive-shaft-to-attachment coupling, and a string trimmer head connected to the drive-shaft-to-attachment coupling. A conventional string trimmer device is designed usually to make a generally horizontal cut on grass and other lawn plants.
A lawn care chore, which is often desirable, is to provide a clean cut lawn edge along a hard surface, such as a sidewalk or driveway. To accomplish a clean cut lawn edge, it is necessary to provide a cutting blade that is oriented substantially vertically. There are devices, known as lawn edgers, which are specially designed to provide a clean cut lawn edge, and such lawn edgers include blades that are oriented substantially vertically.
Therefore, with prior art devices, a string trimmer device can be used to carry out a horizontal cutting function, and a lawn edger device can be used to carry out a vertical cutting function. If both the string trimmer device and the lawn edger are motorized, there are two motors, two handles, two drive shaft housings, two drive shafts, etc.
For purposes of economy and efficiency, it would be desirable if an apparatus could be provided that can carry out both a horizontal cutting function and a vertical cutting function. More specifically, it would be desirable if an apparatus could be provided that can carry out both a horizontal cutting function and a vertical cutting function without using two motors, two handles, two drive shaft housings, and two drive shafts.
As mentioned above, a string trimmer device includes a motor, a handle, a drive shaft driven by the motor, a drive-shaft-to-attachment coupling, and a string trimmer head connected to the drive-shaft-to-attachment coupling. To perform a desired edge trimmer function, it would be desirable if the string trimmer head could be removed from the drive-shaft-to-attachment coupling and replaced with an edger attachment apparatus. In this way, the motor, handle, drive shaft driven by the motor, and drive-shaft-to-attachment coupling of the string trimmer device could be employed along with the edger attachment apparatus to carry out the edge trimmer function.
Still other features would be desirable in an edger attachment apparatus for a string trimmer device. For example, it would be desirable for the edger attachment apparatus to have a height adjustment feature. It would also be desirable for the edger attachment apparatus to have a tilt adjustment feature. Further with respect to the tilt adjustment feature, it would be desirable if the edger attachment apparatus could be locked into a desired tilt adjustment angle.
Thus, while the foregoing body of prior art indicates it to be well known to use a separate string trimmer device and a separate edger device, the current state of the art discussed above does not teach or suggest an edger attachment apparatus for a string trimmer device which has the following combination of desirable features: (1) can carry out both a horizontal cutting function and a vertical cutting function; (2) does not use two motors, two handles, two drive shaft housings, and two drive shafts; (3) permits removal of a string trimmer head from the drive-shaft-to-attachment coupling of a string trimmer device and replacement thereof with an edger attachment apparatus; (4) provides an edger attachment apparatus which has a height adjustment feature; (5) provides an edger attachment apparatus which has a tilt adjustment feature; and (6) provides an edger attachment apparatus which has a tilt adjustment feature which can be locked into a desired tilt adjustment angle. The foregoing desired characteristics are provided by the unique edger attachment apparatus for a string trimmer device of the present invention as will be made apparent from the following description thereof. Other advantages of the present invention over the prior art also will be rendered evident.
SUMMARY OF THE INVENTION
To achieve the foregoing and other advantages, the present invention, briefly described, provides an edger attachment apparatus for attaching to a drive-shaft-to-attachment coupling of a string trimmer device after the string trimmer head has been detached from the driveshaft-to-attachment coupling. The edger attachment apparatus includes an edger driven-shaft housing attachable to the drive-shaft-to-attachment coupling. An edger driven shaft is housed in the edger driven-shaft housing. A relatively small diameter, power transmission driving gear is driven by the edger driven shaft. A relatively large diameter, power receiver gear is driven by the relatively small diameter, power transmission driving gear. A blade assembly drive shaft is connected to the relatively large diameter, power receiver gear. A gear housing is provided for housing the relatively large diameter, power receiver gear. The gear housing is connected to the edger driven-shaft housing. An edger blade assembly is driven by the blade assembly drive shaft. A wheel assembly support is attached to the gear housing, and a wheel assembly is connected to the wheel assembly support.
An edger driven shaft top bearing and an edger driven shaft bottom bearing are located between ends of the relatively small diameter, power transmission driving gear and the edger driven-shaft housing.
A coupling end reception sleeve is connected to an end of the edger driven shaft. The coupling end reception sleeve includes a coupling end reception well.
The relatively small diameter, power transmission driving gear is housed in the edger driven-shaft housing. The edger blade assembly includes a blade support supported by the blade assembly drive shaft, and blades attached to the blade support.
The blade support includes blade reception slots, and the blades are connected to the blade support with blade pivots. A blade assembly shroud is attached to the gear housing for covering the edger blade assembly.
The relatively small diameter, power transmission driving gear is a worm gear, and the relatively large diameter, power receiver gear is a worm-driven gear. The wheel assembly support includes a wheel assembly attachment plate attached to the gear housing.
In accordance with one embodiment of the invention, a tilt adjustment assembly is embodied in the wheel assembly. The wheel assembly includes a wheel tilt plate. A wheel assembly hinge is connected between the wheel tilt plate and the wheel assembly attachment plate. A wheel axle is connected to the wheel tilt plate. A wheel is supported by the wheel axle, and a wheel axle nut is provided for securing the wheel to the wheel axle.
A blade assembly shroud is attached to the gear housing, and the wheel assembly support includes a wheel assembly attachment plate which is attached to the blade assembly shroud.
In accordance with another embodiment of the invention, a height adjustment assembly includes a wheel assembly attachment plate which includes a height adjustment slot and a height adjustment lock bolt received in the height adjustment slot. The wheel assembly includes a wheel axle attached to the wheel assembly attachment plate. A wheel is received on the wheel axle, and a wheel axle nut is provided for retaining the wheel on the wheel axle.
In accordance with another embodiment of the invention, the relatively small diameter, power transmission driving gear is a first bevel gear, the relatively large diameter, power receiver gear is a second bevel gear.
In accordance with another embodiment of the invention, both a height adjustment assembly and a tilt adjustment assembly are provided.
The height
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