Snow blower shovel

A portable rotary snow blower shovel which is lightweight and maneuverable is disclosed. The device uses the drive mechanism from a rotary string trimmer. In place of the string and string guard, the snow blower utilizes an impeller and a substantially cylindrical enclosure. The enclosure includes a cutout opening in a lower portion of the periphery to allow snow to enter. Adjacent the opening is a flat plate which is secured to the inside of the enclosure at an angle in order to direct snow upward toward the impeller. The impeller, which is oriented substantially parallel to the surface being cleared, is circular in shape and has radially projecting blades attached to the upper and lower surfaces thereof. Once the snow is directed upward by the angled flat plate, the blades of the impeller, which are rotating at a high speed, force the snow out an exit conduit adjacent the top of the cylindrical enclosure by centrifugal force. The exit conduit directs the snow upward and away from the path being cleared.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to an attachment that changes the work function of 
devices known by many trade names such as WEEDWACKER, WEEDEATER and 
generically named string trimmer into a snow blower. When the seasons 
change the work function can also be changed back to the original string 
trimmer device. The invention detailed here is specific to 2.54 cm outside 
diameter curved drive tube models, however the concept may be used with a 
variety of models and manufactures limited only by size of the snow blower 
attachment and power requirements. The concept also lends itself to other 
possible devices using an inclined plane plow with an impeller to excavate 
a finely divided media. 
2. Prior Art 
Snow removal from public and private steps, walks, and driveways has 
evolved into different devices to accomplish the desired work an example 
being U.S. Pat. No. 4,378,644 which appears to be a complex, heavy and 
costly device compared to the snow blower shovel for accomplishing the 
same work the snow blower shovel does. While the majority of snow removal 
equipment is not easily stored as the snow blower shovel, equipment built 
thus far is heavy and large such as U.S. Pat. No. 4,597,203 and U.S. Pat. 
No. 4,679,338 which use an impeller disc as does the snow blower shovel. 
While the above inventions are not attachments U.S. Pat. No. 4,418,485 is 
a power take off device use to drive a snow blower from a tractor. There 
are also other devices such U.S. Pat. No. 3,200,519 a powered hand shovel 
blade and U.S. Pat. No. 3,431,661 which is an inclined plane snow plow 
device. However, no devices is known to have the configuration and 
properties of the snow blower shovel. 
SUMMARY OF THE INVENTION 
The principal object of this invention is to remove snow by converting the 
inexpensive and widely used lawn and garden tool, the string trimmer into 
a snow blower, although the concept of the impeller and inclined plane may 
be adapted to a variety other devices and attachments. The resulting snow 
blower will have some unique features that are unavailable on snow 
blowers, such as low cost, low weight, low storage space, increased 
maneuverability, ability to remove snow of any depth, and ability to 
remove snow from steps and walk-ways. 
The unique features of the snow blower invention are the result of 
combining the inclined plane and high-speed impeller. The device works as 
follows: the unit is pushed into the media to be removed and the media 
(snow) is elevated up the inclined plane and into the high-speed 
centrifugal impeller. The media is forced out by centrifugal force into 
the exit conduit that guides snow to a selected dump area. The lightweight 
construction allows the user to turn the entire snow blower unit as 
needed. 
User safety is of great concern in this application because of stored 
energy in the impeller. The flywheel effect may cause the impeller to 
disintegrate upon colliding with a higher density media(ice). However, the 
impeller is constructed of low density components (all Plastic) and also 
having a limited slip impeller construction to reduce this danger and 
increase user safety. The impeller blades are constructed to reduce air 
resistance and increase efficiency of operation. 
In conclusion, the combination of the inclined plane and the impeller 
provide a new and improved snow blower that has broad applications in 
other fields in addition to increasing the usefulness of the string 
trimmer garden and lawn tool.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The preferred embodiment for the attachment snow blower shovel device is 
illustrated in FIG. 2, which shows details of attachment construction 
showing fixture 1 for connecting and supporting the total enclosure 2 to 
drive tube 3 of a string trimmer. The trimmer drive tube 3 provides a 
power take-off which rotates the impeller 4 within and adjacent the top of 
the the total enclosure 2. The flat plate 5 which functions as an inclined 
plane forcing the incoming media to the level of the impeller 4 where the 
velocity of the media is increased by the impeller. The media having 
sufficient velocity, leaves the total enclosure 2 through an opening that 
is covered by media exit conduit 6. The media exit conduit 6 causes the 
media to flow into the nozzle 7. The nozzle 7 is angled to increase the 
distance the media travels from the snow blower shovel to the 
user-selected dump area and guides media away from operator. The ability 
to control the selected dump area is obtained by simply turning the drive 
tube 3 which in turn gives a new direction to the nozzle. The holes a 
prevent build up of trapped snow and ice under the flat plate and reduce 
weight. The snow blower shovel has maneuverablity since the engine weight 
is opposite the preferred embodiment in FIG. 1 with wheels 8 to reduce 
friction. The snow blower shovel is light in weight, the prototype being 
only 1.98 Kg, and constructed of a variety of plastic parts. The total 
enclosure 2 is made from a polyethylene five gallon pail. The flat plate 5 
is (1.588 mm) galvanized steel and bolted to the total enclosure 2. The 
exit conduit 6 and nozzle 7 are made of sheet polystyrene by thermal 
forming and bolted to the total enclosure 2. To prevent the total 
enclosure 2 and the fixture 1 from flexing 0.1175 cm phenolic sheet 10 
stiffens the polyethylene surface. The fixture 1 consists of a cast iron 
base 11 bolted to the stiffened total enclosure 2 surface. Returning to 
FIG. 2 for details of fixture construction, FIG. 2 illustrates a slotted 
2.54 cm polyvinyl chloride 12 fitting is compressed against curved drive 
tube 3 by means of two hose clamps 13. Returning to FIG. 1 the 2.54 cm 
polyvinyl chloride 12 fitting is connected to the threaded cast iron base 
11. Further, the invention is not limited to the above list materials but 
these materials are listed only as a guide in construction of snow blowers 
for string trimmers with 2.54 cm outside diameter curved drive tube. It 
should be noted that the snow blower shovel fixture 1, total enclosure 2, 
and flat plate 5 allow possible construction differences while impeller 4 
construction is more critical. The impeller is illustrated in FIG. 3 with 
an exploded view of the components. The impeller housing 14 and fastening 
bolt 15 of the original string trimmer are reused in the prototype 
however, other string trimmer models may require different adapters. 
Efficient and safe operation were major development goals. The efficient 
operation is limited to the power supplied by the gasoline engine of the 
string trimmer model. The different models and manufactures make efficient 
operation of the impeller 4 even more important. However, it should be 
noted that the operator has control of efficiency because the snow blower 
shovel may be operated at a lower power rate if the operator reduces the 
force used to push it into the media requiring less engine power added 
efficient operation is obtained by reducing the air resistance on the 
impeller 16 blades along with other methods used by those skilled in the 
art of rotating machinery, such as impeller 4 balance. The efficient 
operation does not outweigh the importance of safe operation that is 
provided by construction using all plastic materials excepting for spring 
17, washer 18, and bolt fastener 15, which are all of the center of 
rotation. Further, safe operation is provided by the limited slip 
components. The spring 17 controls the amount of pressure exerted the 
housing 14 on polymeric disk 19. Further adjustments on pressure exerted 
are given by the fastening bolt 15 and lower washer 20. The use of metal 
in the impeller construction is always possible, however prototype 
experiments showed that metal would easily puncture media exit conduit 6 
and still had enough velocity to do significant damage. FIG. 4 illustrates 
other important features of the impeller such as impeller blades 16 made 
of fiberglass reinforced resins and forming a continuous composite 
impeller structure with blade edge holding strap 21 keeping impeller 
blades 16 from changing position when rotated at high speed. The impeller 
4 uses nylon bolts 22 to hold sections together as illustrated in FIG. 6 
showing the top half section 23 and bottom half section 24. FIG. 5 
illustrates how the impeller lower blades 25 on the bottom section are 
larger in size to pick up more incoming media. Air resistance is reduced 
by slotting in the upper and lower blades which increase the impeller 4 
efficiency. The importance of impeller 4 construction in the snow blower 
shovel was demonstrated many times when the engine could not develope the 
operating speed due to air resistance of the impeller blades balance and 
materials problems.