U.S. patent application number 10/108579 was filed with the patent office on 2003-10-02 for system for manually ground driving trenchers and other ground engaging machinery.
Invention is credited to Graham, Curt Timothy, Roose, Lee Allen, Sanders, Ted Jay.
Application Number | 20030182823 10/108579 |
Document ID | / |
Family ID | 28452892 |
Filed Date | 2003-10-02 |
United States Patent
Application |
20030182823 |
Kind Code |
A1 |
Sanders, Ted Jay ; et
al. |
October 2, 2003 |
System for manually ground driving trenchers and other ground
engaging machinery
Abstract
A manual drive system is shown for moving trenchers and other
small ground engaging equipment while in operation. A preferred
embodiment of the system includes a pedal providing the mechanical
advantage needed for an operator to apply sufficient thrust for
such operations and a cleat for engaging the ground to provide the
motive force in one instance or a ratchet engaging a transport
wheel in another instance.
Inventors: |
Sanders, Ted Jay; (Chariton,
IA) ; Roose, Lee Allen; (Pella, IA) ; Graham,
Curt Timothy; (Lynnville, IA) |
Correspondence
Address: |
STURM & FIX LLP
206 SIXTH AVENUE
SUITE 1213
DES MOINES
IA
50309-4076
US
|
Family ID: |
28452892 |
Appl. No.: |
10/108579 |
Filed: |
March 28, 2002 |
Current U.S.
Class: |
37/244 |
Current CPC
Class: |
E02F 5/14 20130101; E02F
5/06 20130101 |
Class at
Publication: |
37/244 |
International
Class: |
E01H 005/09 |
Claims
We claim:
1. Apparatus comprising: a frame; transport wheels operatively
attached to said frame for moving said frame from place to place; a
tool operatively attached to said frame, said tool having moving
parts for contacting material to be moved; a power unit operatively
attached to said frame and operatively attached to said tool for
moving said parts whereby said parts can move material disposed
adjacent to said frame; and a ground engaging member having a
raised non-ground engaging position and a plurality of ground
engaging positions for causing said frame to move in a
predetermined direction as said ground engaging member moves from
said non-ground engaging position to progressive ones of said
plurality of ground engaging positions.
2. The apparatus of claim 1 including a ground engaging cleat
member operatively attached to said frame and movable between a
raised non-ground engaging position and a lowered ground engaging
position for tending to hold said frame from moving in a direction
opposite to said predetermined direction.
3. The apparatus of claim 1 including a lever operatively pivotally
attached to said frame for causing said ground engaging member to
move between said raised non-ground engaging position and said
plurality of ground engaging positions.
4. The apparatus of claim 3 wherein said ground engaging member is
operatively pivotally attached to said lever.
5. The apparatus of claim 4 wherein said lever is a pedal for being
pushed downwardly by a foot of an operator of said apparatus.
6. The apparatus of claim 1 including a handle operatively attached
to said frame for grasping by said operator.
7. The apparatus of claim 6 wherein said tool is a trencher and
said predetermined direction is a direction of trenching and said
frame is also moveable in a direction opposite to the direction of
trenching.
8. The apparatus of claim 7 wherein when said ground engaging
member moves from said non-ground engaging position to said
plurality of ground engaging positions said ground engaging member
pivots in said direction opposite to a direction of trenching,
thereby causing said frame and said trencher to move in said
direction of trenching.
9. The apparatus of claim 1 wherein said tool is a roto-tiller.
10. The apparatus of claim 1 wherein said tool is a concrete
saw.
11. The apparatus of claim 1 including means for locking said
ground engaging member in a raised transport position thereof.
12. The apparatus of claim 1 including a spring operatively
attached to said frame for biasing said lever to an upward
position.
13. The apparatus of claim 1 including a spring operatively
attached to said frame for biasing said ground engaging member to
said raised transport position thereof.
14. The apparatus of claim 13 wherein said spring is directly
pivotally attached to said lever and is thereby indirectly attached
to said frame.
15. Apparatus comprising: a frame; transport wheels operatively
attached to said frame for moving said frame from place to place; a
tool having moving parts, said tool being operatively attached to
said frame; a power unit operatively attached to said frame and
operatively attached to said tool for moving said parts whereby
said parts can move material disposed adjacent to said frame; a
lever operatively pivotally attached to said frame; a ratchet wheel
operatively attached to said transport wheels, said ratchet wheel
having teeth disposed about the outer periphery thereof; and a link
member operatively pivotally attached to said lever and biased
toward said ratchet wheel for causing said link member to contact
said teeth and thereby turn the transport wheels whereby the frame
will be moved in a predetermined direction as said link member is
moved downwardly by movement of said lever.
16. The apparatus of claim 15 including a ground engaging cleat
member operatively attached to said frame and movable between a
raised non-ground engaging position and a lowered ground engaging
position for tending to hold the frame from moving said frame in a
direction opposite to said predetermined direction.
17. The apparatus of claim 15 wherein said lever is a pedal for
being pushed downwardly by a foot of an operator of said
apparatus.
18. The apparatus of claim 15 including a handle operatively
attached to said frame for grasping by said operator.
19. The apparatus of claim 15 wherein said tool is a trencher and
said predetermined direction is a direction of trenching.
20. The apparatus of claim 15 wherein said tool is a
roto-tiller.
21. The apparatus of claim 15 wherein said tool is a concrete
saw.
22. The apparatus of claim 15 wherein said tool is a vibratory
plow.
23. The apparatus of claim 15 wherein said tool is a snow
blower.
24. The apparatus of claim 1 wherein said tool is a vibratory
plow.
25. The apparatus of claim 1 wherein said tool is a snow blower.
Description
TECHNICAL FIELD
[0001] This invention relates generally to a system for providing
for manually moving trenchers and other small ground engaging
equipment while in operation, as opposed to in transit. More
specifically, it relates to an apparatus including a pedal
providing the mechanical advantage needed for an operator to apply
sufficient thrust for such operations and a cleat for engaging the
ground to provide the motive force in one instance or a ratchet
engaging a transport wheel in another instance. In addition, this
invention comprises a separate cleat for resisting the plunge drive
force that occurs when initially lowering the trenching boom
assembly into the ground.
BACKGROUND ART
[0002] Trenching is required for the below ground installation of
many types of utilities including electrical power, gas, telephone,
water and sewer. Other types of conduits installed below ground
include water lines for lawn irrigation, and drainage pipes. Many
types of machines have been developed to mechanize digging trenches
for such purposes. One type of machine, commonly known as a
trencher, typically includes a boom assembly, which guides an
excavating chain. The boom assembly is mounted to a frame or frame
assembly, which typically includes a drive sprocket for the
excavating chain and a power unit such as an engine to power the
drive sprocket. Ground supports are attached to the frame ranging
from rubber pneumatic tires to tracks. This would include transport
wheels. These ground supports assist to position the frame and boom
assembly relative to the ground and to propel the machine for
transport and during excavation. Many of these machines have been
designed to complete relatively large jobs wherein the required
trenches are relatively deep, often at least 3 to 4 feet deep, and
long, sometimes measuring miles in length. Such machines are
typically designed such that the operator can ride on the machines.
The operator's station typically includes controls for varying the
ground speed during excavation (provided by controlling the drive
to the ground supports) which is critical to the proper operation
of the excavating chain.
[0003] Control of the position of the boom assembly is also
provided in order to control the depth of excavation and to provide
a transport mode wherein the boom assembly is raised above the
ground surface.
[0004] Often, utilities and conduits are installed after
landscaping is completed, or in spaces where the larger machines
cannot maneuver or where they would cause excessive disruption of
the surface. For these instances walk behind trenchers have been
developed wherein the machine is much smaller, and the operator
walks beside or behind the trencher. An example of such a machine
can be found in U.S. Pat. No. 5,212,896. The basic components are
nearly identical to those found on the larger machines, including a
frame, power unit (engine), excavation boom assembly, and transport
wheels. In the previously cited reference the machine is propelled
during trenching by at least one of the ground engaging wheels,
which is positively driven by the engine.
[0005] For many uses of such walk-behind trenchers the features
provided by the ground drive are important, namely reducing the
required operator effort to operate the trencher thereby increasing
the capability and productivity of the trencher. Providing proper
control of the ground drive system involves several components and
resulting significant cost.
[0006] There is an increasing demand for less expensive, more
manually operated machines for use by individuals on a limited
basis. In the less demanding applications where a limited
excavation depth and excavating speed is acceptable, the ground
drive is not as critical, and a new ground drive system is
required.
[0007] In addition to trenching machines many other types of
manually operated machines require ground drive capability.
Examples include roto-tillers used to cultivate gardens, concrete
saws used to cut expansion joints in concrete, vibratory plows for
burying cable, and snow blowers for removing snow from drives and
walks. These machines would benefit from an improved ground
drive.
DISCLOSURE OF THE INVENTION
[0008] The present invention involves a manual drive system,
including no components powered by the engine. It is ideal for use
with a walk behind trencher. The trencher includes a power unit
(such as an engine or a motor) mounted on a frame supporting an
excavating boom assembly and chain drive sprocket having teeth for
digging and removing soil. The frame is supported on two transport
wheels. The wheels rotate freely, allowing the trencher to be
propelled by the operator pushing or pulling on a handle that is
attached to the frame. The use of the handle is primarily intended
for transporting the trencher while it is not excavating.
[0009] The present invention is a manual ground drive, separate
from the handle that allows the human operator to provide the
motive power to propel the trencher in the trenching direction,
during excavation. This separate mechanism provides many important
features including:
[0010] 1. Ergonomic efficiency: the operator propels the machine in
a manner to avoid excessive use of the back.
[0011] 2. Mechanical efficiency: the ground drive force is applied
to the frame at a point that the resultant effect on the excavator
is to enhance performance.
[0012] 3. Mechanical efficiency: use of the drive mechanism results
in a transfer of weight such that the trencher's weight is utilized
to assist in developing the drive force.
[0013] 4. Mechanical efficiency: use of the drive mechanism results
in a transfer of weight such that the trencher's weight is utilized
to assist in keeping the boom assembly in the ground while
trenching, thereby providing consistent trench depth.
[0014] In addition, a simple and reliable transport position is
provided for this drive mechanism so that the drive mechanism does
not interfere with the normal transport of the trencher.
[0015] The present invention further provides for a mechanism that
prevents travel of the trencher in a direction opposite to that of
trenching. This is critical in that the forces developed during
trenching will tend to oppose trenching. If not counteracted by
some mechanism, the operator will be forced to manually control the
excavator to prevent this movement.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a schematic side elevation view of a trencher in a
transport mode.
[0017] FIG. 2 is a schematic side elevation view of a trencher in
an excavation mode.
[0018] FIG. 3 is a detailed side view of the ground drive assembly
in a first, raised, position.
[0019] FIG. 4 is a detailed side view of the ground drive assembly
in a second, partially lowered, position.
[0020] FIG. 5 is a detailed side view of the ground drive assembly
in a third, fully lowered, position.
[0021] FIG. 6 is a detailed perspective view of the ground drive
assembly.
[0022] FIG. 7 is a detailed schematic side elevation view of a
trencher illustrating other features of the ground drive
system.
[0023] FIG. 8 is a perspective view of a trencher.
[0024] FIG. 9 is a free-body diagram of a frame of a trencher.
[0025] FIGS. 10a-10f are schematic side elevation views of a ground
drive assembly.
[0026] FIG. 11 is a schematic side elevation view of a second
embodiment using a ratchet mechanism on the transport wheels or
axle.
[0027] FIG. 12, on the same sheet as FIG. 6, is a detailed
schematic view of selected components of the ground drive assembly
trencher.
BEST MODE FOR CARRYING OUT THE INVENTION
[0028] The preferred embodiments are shown in the drawings and
described with the understanding that the present disclosure is to
be considered an exemplification of the invention which is not
intended to limit the invention to the embodiments disclosed.
[0029] Referring now to the drawings, wherein like reference
numerals indicate like parts throughout the several views, a walk
behind trencher is represented in its entirety by reference numeral
10. Trencher 10 includes a frame 12, a power unit 14, which is
internal combustion engine but could be something else such as an
electric motor, transport wheels 16 (which could also be tracks),
an operator station 18, and an excavating boom assembly 20.
[0030] As shown in FIG. 1 the trencher 10 is in position to begin
forming a trench with the transport wheels 16 and the frame 12
resting on the ground surface 8 and completely defining the
orientation of the trencher 10. In this position the excavation
boom assembly 20 is in the raised position for transport. The boom
assembly 20 includes the boom 22, the idler roller 24 which is
rotatably mounted onto the boom 22, and the excavating chain
assembly 26. The excavating chain assembly 26 includes moving parts
for contacting the material to be moved, which, in this case, are
cutting teeth 28 mounted onto the base chain 30. The cutting teeth
28 can be any number of known types of teeth from cup cutters to
rotary bits, depending on the ground conditions.
[0031] In this position the trencher can be transported by the
operator by pushing down or pulling on handle 40 to rotate frame 12
counterclockwise (as seen in FIG. 1) around the axle of the ground
engaging wheels 16 to raise the frame 12 off the ground so that the
trencher is completely supported by the ground engaging wheels 16.
Once in that position, the trencher can be propelled by the
operator to transport it to the desired location to start
trenching. Once in the correct location, the operator will start
the power unit. The operator can then make several adjustments to
the machine from the operator's station 18.
[0032] Operator's station 18 includes the handle 40, chain drive
control 42, boom height control 44, ground drive assembly 45. The
handle 40 is used by the operator for transport, and to help
control the trencher during trenching. The chain drive control 42
is used to engage and disengage the drive from the power unit 14 to
the drive sprocket 34, which is the only system driven by the power
unit on the trencher. When the chain drive control 42 is pulled
toward the handle 40, the drive will engage; when released, the
drive will disengage.
[0033] The boom height control 44 is used to control the
orientation of the boom assembly 20 relative to the frame 12. FIGS.
7 and 8 illustrate the boom height control 44 including an
actuating arm 54, latching bar 56, latch plate 58, spring 60 and
link 62. The spring 60 pulls the latching bar 56 into one of four
grooves 59, which define four positions. In order to change the
orientation the operator pulls on the upper end of latching bar 56,
which will lift the opposite end of the latching bar 56 out of the
groove 59 and allow the actuating arm 54 to rotate relative to the
frame 12. This rotation will move link 62 as can be seen in FIG. 7,
which has one end pivotally attached to the actuating arm 54 with
the other end (not shown) pivotally attached to the excavating boom
22. Once the boom height control 44 is positioned such that latch
bar 56 is in the desired groove 59 the latch bar 56 is released and
the orientation of boom 22 is fixed.
[0034] The operator will then pull on the chain drive control 42 to
engage drive to the excavating chain, typically while pushing down
on the handle 40 to raise the excavating boom assembly 20 off the
ground. To start excavating the trench, the operator will allow the
trencher to rotate clockwise (as oriented in FIG. 7) around the
axle of the ground engage wheels 16 with the excavating chain
powered. The boom assembly 20 will thus be lowered, plunging into
the ground, until the frame 12 is resting on the ground as shown in
FIG. 2. This first step of excavation is known as plunge
cutting.
[0035] This initial plunge cut requires that the trencher be held
stationary while the excavating chain is contacting the ground
generating a plunge drive force, attempting to propel the trencher
from left to right, as shown in FIG. 2. In a trencher with ground
drive this plunge drive force is offset by the ground drive system
connected to the transport wheels. With the trencher of the present
invention there is no drive mechanism associated with the transport
wheels 16. Thus, some other means of counteracting the plunge drive
force is required. If no other mechanism were provided, the
operator would be required to hold the trencher to counteract this
plunge drive force.
[0036] In the embodiment illustrated, specifically in FIGS. 2 and
7, a ground engaging cleat member 52 is designed to counteract the
plunge drive force. The ground engaging cleat 52 is pivotally
attached to the frame 12. It is positioned with a chain link 64,
which is connected to the boom height control link 62 such that
when the boom is raised to the transport position ground engaging
cleat member 52 is raised, as shown in FIG. 7. When the boom is
lowered to an excavating position the ground engaging cleat 52 is
lowered as shown in FIG. 2. In the lowered position the ground
engaging cleat 52 will prevent the trencher from moving in a
direction opposite the direction of trenching (toward the boom),
thus counteracting the plunge drive force and eliminating the need
for the operator to hold the trencher against this plunge drive
force.
[0037] Once the excavating boom is properly lowered into the
ground, as shown in FIG. 2, the trencher is propelled toward the
operator 's station 18 in order to extend the length of the trench.
Without any other mechanism, and as found on currently available
manually operated models, the operator pulls on the handle with
force 66 to move the trencher a relatively short distance to the
left. This action of pulling on the handle effectively applies a
counterclockwise moment (as observed in FIG. 2) on the trencher,
which tends to rotate the trencher counterclockwise and is normally
accompanied by a significant amount of lifting of the boom
assembly. The trencher will then be held in position while
effectively plunge cutting again to get back to the desired trench
depth. In this manner the trench is extended, effectively
performing many small plunge cuts. The present invention however,
provides an alternate method of propelling the trencher during the
trenching process.
[0038] The ground drive assembly 45 shown in FIG. 3 is provided to
aid in propelling the machine (FIG. 3 depicts any number of
manually driven machines as indicated by the generic component 100,
taking the place of the trenching mechanism, the roto-tiller
blades, concrete saws, vibratory plows, snow blowers, etc.). It
includes pedal 46 and ground engaging member 50. In use the
mechanism starts in the non-ground engaging position illustrated in
FIG. 3 with the ground drive lever (shown as a pedal, but could be
any lever, including the handle 40) 46 in the raised position due
to the force of spring 72. The ground drive lever 46 is pivotally
attached to the frame at pivot point 74. Ground engaging member 50
is pivotally attached to the ground drive lever at pivot point 76.
The ground engaging member 50 is constructed from a single plate,
with two ears 94 bent up as can be seen in FIG. 6, and a rear
surface 98. The ears 94 contain holes defining the ground engaging
member pivot point 76. Ground drive lever 46 also includes
cooperating holes to define the ground engaging member pivot point
76. The ground engaging member 50 overlaps the ground drive lever
46 such that the range of motion is restricted. The ground engaging
member 50 cannot rotate clockwise (as oriented in FIG. 3) around
its pivot point 76 any further than as shown in FIG. 3. As shown in
FIG. 6, this point is defined when the edge of rear surface 98
contacts the lever 46. Spring 78 pulls the ground engaging member
50 into this position.
[0039] To propel the trencher the operator 6 depresses the ground
engaging member 46 down with foot force 68 as shown in FIG. 4. When
the ground engaging member 50 contacts the ground, the trencher
begins to be propelled. Looking at the free-body diagrams of the
frame and of the drive mechanism as illustrated in FIGS. 9 and 10
one can see the advantages of this drive arrangement.
[0040] FIG. 9 illustrates a free-body diagram of the frame 12 and
handle 40. The potential forces applied to the frame can be
summarized by the six forces: handle force 66, the operator's force
on the handle 40, ground drive force 80, the force that the ground
drive mechanism can generate, wheel force 82, the force generated
by the wheels to support the load, excavate force 84, the force the
excavating chain develops while excavating, ground force 85, the
force provided by the ground surface 8 (FIG. 1), and the machine's
weight 83. In propelling the trencher with just the handle force
66, it is evident, by looking at the sum of the moments about the
transport wheels' axle 77, that the handle force 66 generally must
be in a direction opposite that required (and shown 66) to propel
the trencher, from right to left, in order to counteract the
excavate force 84. Excavate force 84, as illustrated, will tend to
make the frame rotate counterclockwise around the wheel axle 77.
Thus, the operator typically must push on handle 40, in a direction
opposite that shown, for force 66 to force the frame to rotate
clockwise and force the excavating assembly 20 to stay engaged with
the ground in order to maximize the excavating efficiency. Thus, it
is unavoidable that when the trencher is propelled by pulling on
handle 40 with force 66, the frame is forced to rotate
counterclockwise about the wheel axle 77, effectively acting in
conjunction with the excavate force 84. This transfers load to the
transport wheels and lifts the boom 22 out of the ground,
effectively reducing the excavator's capacity and productivity.
[0041] With the ground drive of the present invention there is no
force applied to the handle. Handle force 66 is zero, and the
ground drive assembly 45 is utilized to propel the trencher; with a
completely different effect on the excavate force 84.
[0042] The effective angle of the ground drive force 80, .alpha.,
changes with the position of the ground drive mechanism as
illustrated in FIG. 10. In the position shown in FIG. 10a the
ground engaging member 50 is just beginning to contact the ground
8. In this position the member 50 cannot rotate counterclockwise on
its pivot 76 due to the construction described earlier. Assuming
that the contact between the ground 8 and the ground engaging
member 50 is sound, the assembly, pedal 46 and ground engaging
member 50, will be forced to pivot around that point of contact 86.
The resulting ground drive force 80 will thus be perpendicular to a
line drawn between the contact point 86 and the pivot point 74,
resulting in an effective angle .alpha. as illustrated. As the
pedal 46 is depressed further, effective angle .alpha. will
decrease as the line drawn between contact point 86 and pivot point
74 becomes closer to vertical as shown in FIGS. 10b and 10c. In
FIG. 10d the line drawn between the contact point 86 and pivot
point 74 is vertical, and the ground drive assembly 45 is poised to
go over-center. Over-center means that the cleat 50 will begin to
pivot counterclockwise relative to the pedal 46, as shown in FIGS.
10e and 10f.
[0043] As the operator 6 begins to depress the lever 46 the pivot
point 74 is raised, as is evident by comparing FIG. 10b with FIG.
10a. This will result in a transfer of forces. As pivot point 74 is
raised, force 82 is partially transferred to pivot point 74. The
balance of force 82 is transferred to add to force 85. The wheels
no longer provide support as the ground drive 45 is now supporting
the machine. This results in an increase in the ability of machine
weight force 83 to counteract excavate force 84. Looking again at
FIG. 9, and summing moments around the transport wheel axle's axis
77, as ground drive force 80 is increased, force component 80y
(shown in FIG. 10) works in conjunction with machine weight 83 to
counteract excavate force 84. In addition, force component 80x
(shown in FIG. 10) counteracts excavate force 84. Thus, as the
operator propels the machine with the ground drive assembly 45, the
excavator boom assembly will simultaneously be forced into contact
with the ground actually improving the excavator's capacity and
productivity.
[0044] The complete drive cycle defined by one stroke of the ground
drive mechanism 45, illustrated in FIG. 10, results in the
following conditions:
[0045] 1. At FIG. 10a the excavator frame 12 is initially urged
vertically by vertical force 80.sub.y while simultaneously urged
horizontally by a horizontal force 80.sub.x resulting in an initial
transfer of load from the transport wheels to the contact point 86
and excavator pivot 88. The increased load at excavator pivot 88
will enhance the excavator performance.
[0046] 2. At FIGS. 10b and 10c the excavator frame 12 has been
raised, with the transport wheels potentially not carrying any
weight. The effective angle a changes and the resulting ground
drive force 80 is more effectively horizontal, as can be seen by
comparing horizontal force 80.sub.x to vertical force 80.sub.y.
[0047] 3. At FIG. 10d the ground drive assembly 45 is at the point
of going over-center, at which point the effective angle a is zero
and the resulting force will be exclusively horizontal. This is due
to the free rotation allowed by the ground drive pivot point
76.
[0048] 4. At FIGS. 10e and 10f the ground engaging member 50
continues to pivot about its pivot point 76, the pivot point 74
lowers, with gravity, and the trencher continues to be propelled
from right to left. In this stage of the cycle gravity is actually
assisting to propel the trencher.
[0049] At the end of this cycle the operator will release lever 46,
the spring 72 will retract lever 46 to its original position as in
FIG. 10a, spring 78 returns ground engaging member 50 to its
original position as in FIG. 10a, and the drive cycle is ready to
start again. This drive cycle can be completed as necessary to
extend the trench to the desired length.
[0050] When the trench is complete the operator can transport the
trencher. As explained earlier this is accomplished by pulling on
handle 40 to rotate the trencher counterclockwise (as oriented in
FIG. 1) around the wheels 16 in order to raise the boom assembly 20
out of the trench. However, as shown in FIG. 2, the amount that the
trencher can be rotated counterclockwise is limited by ground
engaging member 50, as it will quickly contact the ground. In order
to increase the distance the trencher can be rotated, a latch 48
for the ground engaging member 50, is provided. As illustrated in
FIGS. 6 and 12 latch 48 is mounted on pivot 96 and includes a flat
92 and tab 90. It freely rotates on pivot 96 such that it hangs, by
gravity, in the position illustrated in FIG. 6. When the operator
wishes to latch the ground engaging member 50 up the ground
engaging member is pushed to rotate clockwise until the edge of
rear surface 98 moves far enough to allow the latch 48 to rotate,
by gravity, counterclockwise into the position shown in FIG. 12. In
this position, ground engaging member 50 is latched up and out of
the way for transport, etc.
[0051] The above description is one embodiment of the invention. A
second potential embodiment is one wherein the handle 40 could be
constructed with a pivot such that the ground drive assembly 45
could be actuated by the handle. Thus, the handle becomes the lever
described above.
[0052] An additional embodiment is illustrated in FIG. 11 and
entails utilizing the lever 46 (or handle 40) to engage a ratchet
wheel attached to the transport wheels 16, the axle on which at
least one transport wheel is rigidly attached, or additional ground
driving wheels. Here, the machine is manually driven using wheels
which engage the surface of the ground sufficiently to apply a
horizontal thrust. Generic component 100 indicates that FIG. 11
represents any number of manually transported machines (some of
which are referred to above), including, but not limited to, a
trencher.
[0053] To operate the FIG. 11 embodiment, the operator 6 presses
down on pedal 46. Link 90 engages tooth 91 and causes wheel 16 to
turn in the direction of trenching. Spring 92 keeps link 90 engaged
against teeth 91. When stroke of pedal 46 is completed, operator 6
lifts foot and spring 72 returns pedal 46 to original position,
ready for next stroke. During return, trenching stake 52 engages
the ground and holds the machine in place, resisting movement in a
direction opposite trenching, until the beginning of the next
stroke.
[0054] This invention is not intended to be limited to trenching
equipment. Additional equipment on which this invention has
application include roto-tillers, concrete saws, vibratory plows,
and snow blowers.
[0055] Obviously many other modifications and variations of the
present invention are possible in light of the above teachings. It
is therefore to be understood that, within the scope of the
appended claims, the invention may be practiced otherwise than as
specifically described.
* * * * *