Lawn mower control device

A control apparatus for a lawn mower which includes two coupling members pivotable about a single axis. The coupling members are connected to a drive mechanism and a braking mechanism for the lawn mower. The members are coupled so that a forward pushing force applied by the operator actuates forward driving movement of the lawn mower and a pulling force actuates the braking mechanism when the drive mechanism is placed in a forward gear.

The present invention relates generally to an apparatus and method for 
controlling a lawn mower. More particularly, the invention relates to a 
novel apparatus and method for controlling a lawn mower whereby forces 
applied by the operator are translated into powered mower motion in 
substantially the same direction as the operator-applied forces. 
A multitude of devices for controlling self-propelled lawn mowers are 
disclosed in the prior art. Many of these devices do not provide a 
"deadman" control whereby release of the control causes stoppage of drive 
wheels. Those prior art designs incorporating "deadman" control are 
typically complex and therefore require more frequent and expensive 
maintenance. 
Additionally, to induce powered mower movement in a desired direction, many 
prior art devices require the operator to apply forces in a direction 
opposite the desired direction. This is counterintuitive and can cause 
operator injury when the mower does not function as the operator expects. 
Further, many conventional drive mechanisms require engaging a drive belt 
with an idler pulley to increase the drive belt tension and to produce 
driving forces. Producing this tension requires relatively large forces 
and such conventional devices can quickly fatigue the operator. For 
example, many prior art designs utilize hand grip devices which must be 
continually squeezed by the operator to produce the required belt tension 
for drive means actuation. Alternatively, some prior devices utilize 
locking mechanisms for retaining the tension on the belt, but do not 
provide the important deadman control for safety purposes. Additionally, 
many of these prior devices do not allow one-handed operation of the mower 
so that the operator may push aside obstructions such as tree branches and 
the like while mowing. 
It is therefore an object of the invention to provide an improved control 
device and method of operation for a lawn mower. 
It is another object of the invention to provide a novel lawn mower control 
device which complies with current and proposed ANSI safety standards. 
It is a further object of the invention to provide a novel method and 
apparatus for controlling a self-propelled lawn mower which engages a 
braking mechanism when external forces are removed from the device. 
It is still another object of the invention to provide an improved lawn 
mower control device which is relatively simple in construction and rugged 
in design. 
It is yet a further object of the invention to provide an improved 
apparatus and method for controlling a self-propelled lawn mower whereby 
forces applied by the operator induce powered lawn mower movement in 
substantially the same direction as the operator-applied forces. 
It is an additional object of the invention to provide a novel lawn mower 
control device which includes a component for quickly adjusting a drive 
actuation feature. 
It is still a further object of the invention to provide an improved lawn 
aerator control device which complies with ANSI safety standards. 
It is still a further object of the invention to provide an improved lawn 
mower control device which minimizes operator fatigue while providing a 
"deadman" safety feature. 
It is yet another object of the invention to provide an improved lawn mower 
control device which enables the operator to control driving and braking 
forces of a lawn mower with one hand. 
It is yet an additional object of the invention to provide an improved lawn 
mower control device which pivots about only a single axis, thereby 
increasing the simplicity and reliability of the device. 
Other advantages and features of the invention, together with the 
organization and manner of operation thereof, will become apparent from 
the following detailed description when taken in conjunction with the 
accompanying drawings, wherein like elements have like numerals throughout 
the drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring now to the figures and more particularly to FIG. 1, a lawn mower 
control device constructed in accordance with one form of the invention is 
indicated generally at 10. A handle 12 supports both a pivotable left 
control assembly 14 and a pivotable right control assembly 16 between the 
ends of the assemblies. In the most preferred form of the invention, the 
assemblies 14, 16 are supported by the handle substantially at or near the 
centers of the assemblies 14 and 16. The left control assembly 14 and the 
right control assembly 16 are mirror images of each other and are 
independently operable from each other. Accordingly, the details of the 
right control assembly 16 which are discussed herein herein also apply to 
the left control assembly 14 which operates in a substantially identical 
fashion to the right control assembly 16 in this embodiment. 
As shown in FIG. 1, the right control assembly 16 preferably comprises a 
substantially C-shaped member 18 connected to a member support 20 at a 
member support tapper end 22 by welding or other conventional techniques. 
While a substantially C-shaped member is described for nonlimiting 
illustrative purposes, other shapes such as elongate members, rectangles, 
polygons, and ellipses can be used equivalently. A member support lower 
end 24 is connected to a pivot rod 26 and a lever 28. The pivot rod 26 is 
inserted into a collar 30 located on a bar 32 on the handle 12 for pivotal 
engagement therewith. The pivot rod 26 is retained in pivoting engagement 
with the collar 30 through the use of cotter pins 34 which are inserted 
into holes drilled through the pivot rod 26. 
The substantially C-shaped member 18 is shaped to generally conform to the 
shape of upper portion 36 of the handle. This enables the operator to 
comfortably and easily retain the substantially C-shaped member 18 in a 
position adjacent to handle 12. Clockwise pivoting movement of the right 
control assembly 16 (as viewed in FIG. 3) is limited by the upper portion 
36 of the handle 12. 
Preferably, the lever 28 is connected to an adjustable rod 38 as shown in 
FIG. 1, though a nonadjustable rod or other conventional linkage means can 
be used satisfactorily. The length of the adjustable rod 38 can be 
adjusted by a conventional turnbuckle mechanism 40 with a locking nut 42 
as shown in FIGS. 1 and 2. The adjustable rod 38 is pivotally engaged with 
a lever hole 44 disposed in the lever 28. A conventional pin 46 retains 
the adjustable rod 38 in pivotal engagement and also enables quick and 
simple length change of the adjustable rod 38. 
Changing the length of the adjustable rod 38 is accomplished by 1) removing 
one of the conventional pins 46 to free one of ends 48 of the adjustable 
rod 38; 2) loosening the locking nut 42 from binding engagement with the 
turnbuckle mechanism 40; 3) rotating the end of the adjustable rod 38 
about the longitudinal axis of the turnbuckle mechanism 40 to achieve the 
desired length; 4) tightening the locking nut 42 until it engages the 
turnbuckle mechanism 40, thereby preventing further adjustable rod 38 
rotation about the longitudinal axis of the turnbuckle mechanism; and 5) 
reinserting the end 48 of the adjustable rod 38 into its corresponding 
hole, and pinning the end 48 in place with the conventional pin 46. 
The lower of the ends 48 of the adjustable rod 38 is pivotally connected to 
a bell crank 50 by its insertion into a hole in the lower portion of the 
bell crank 50. The lower adjustable rod end 48 is retained in pivotal 
engagement with the bell crank 50 by the conventional pin 46. 
An idler pulley 52 is mounted to the bell crank 50 by an idler bolt 54. The 
idler bolt 54 is inserted through an idler bearing 56 about which the 
idler pulley 52 rotates. The idler pulley 52 moves with the bell crank 50 
as the bell crank 50 pivots in response to movement of the adjustable rod 
38. 
The bell crank 50 is pivotally connected to a housing 58 by inserting a 
bolt 62 through a bushing 60 connected to the bell crank 50. The bolt 62 
is first inserted through a safety guard 63 which helps prevent 
entanglement in a drive belt 88. The bell crank 50 is biased in a 
counterclockwise direction (as viewed in FIG. 2) by a spring 64 which is 
attached to both the bell crank 50 and the housing 58. The spring 64 
exerts spring force SF as shown in FIG. 2. A brake rod 66 is inserted into 
and pinned to a front portion of the bell crank 50 for pivotal engagement 
therewith. The lower brake rod portion 68 is connected to a brake arm 70 
which can engage a brake band 72 as shown in FIGS. 1, 2 and 3. 
As the brake rod 66 is moved upward by counterclockwise rotation of the 
bell crank 50, the brake arm 70 rotates about a brake arm pivot 74 as 
shown in FIGS. 2 and 3. This rotation causes the diameter of the brake 
band 72 to decrease until the brake band 72 engages a brake drum 76 
disposed generally within the interior of the brake band 72. The brake 
band 72 comprises conventional material with a relatively high coefficient 
of friction so that the contact between the brake band 72 and brake drum 
76 produces high frictional losses. This frictional engagement resists 
rotation of the brake drum 76, thereby resisting rotation of a drive wheel 
78 connected to the brake drum 76. 
As shown in FIG. 1, a drive shaft 80 (which can be connected to a 
transmission, a hydrostatic motor or other conventional drive mechanism 
82) is connected to a drive pulley 84. The drive shaft 80 is preferably 
inserted through a drive bearing 86 located between the drive pulley 84 
and the drive mechanism 82. This arrangement helps to reduce stresses on 
the drive shaft 80 and drive mechanism 82. The drive pulley 84 engages a 
drive belt 88 which in turn engages a drive wheel pulley 90. The drive 
wheel pulley 90 is attached to the drive wheel 78 for rotation therewith. 
As shown in FIGS. 1 and 2, in a condition when no external forces are 
applied to the lawn mower control device 10, the spring force SF from the 
spring acting on the bell crank 50 relaxes the tension on the drive belt 
88. Accordingly, the drive belt 88 is free to slip on the drive pulley 84 
and drive wheel pulley 90, thereby providing a neutral configuration. 
Simultaneously, the spring force SF causes the brake arm 70 to engage the 
brake band 72 with the brake drum 76, thereby preventing movement of the 
lawn mower. The braking force can be increased by pivoting the 
substantially C-shaped member 18 in a counterclockwise direction as viewed 
in FIG. 2. This pivoting is typically induced by the operator pulling on 
the upper portion of the substantially C-shaped member 18, and this motion 
is an intuitive reaction when the operator wants to hold the lawn mower in 
place. The pivoting action adds additional force to the spring force SF 
produced by the spring 64 thereby further relaxing tension on the drive 
belt 88 and further tightening the brake band 72 on the brake drum 76. 
As shown in FIGS. I and 3, when a gear box selector 92 places the drive 
mechanism 82 in a forward gear, pushing the upper portion of the 
substantially C-shaped member 18 toward the handlebar causes the idler 
pulley 52 to engage the drive belt 88 and increase the tension thereof. 
This engagement (which is adjustable by changing the length of the 
adjustable rod 38) gradually ceases the slippage between the drive belt 
88, the drive pulley 84 and the drive wheel pulley 90. Simultaneously, the 
brake arm 70 is moved to relax the brake band tension, thereby allowing 
forward movement in response to the driving force resulting from 
engagement with the drive belt 88 of the drive pulley 84 and drive wheel 
pulley 90. Once again, this feature comports well with ergonomic 
engineering principles by actuating forward drive wheel movement in 
response to a forward pushing force from the operator. 
Further, when the operator applies a pushing force to only the right 
control assembly 16, driving forces are actuated only on the right side of 
the mower. This causes the mower to turn left if the left control assembly 
14 is untouched or pulled back. Accordingly, this embodiment of the 
invention provides intuitive and predictable control of the lawn mower. 
As shown in FIGS. 1 and 4, when the gear box selector 92 places the drive 
mechanism 82 in a reverse gear, pulling up on the lower portion of the 
substantially C-shaped member 18 induces the same mechanical action as 
described for the forward drive activation. Because the drive pulley 84 is 
now rotating in the opposite direction due to the position of the gear box 
selector 92, rotation of the drive wheel 78 causes the lawn mower to back 
up in response to the pulling force applied by the operator. In this way, 
motions which are intuitive to the operator actuate the corresponding 
movement of the lawn mower. Additionally, if the lawn mower begins to 
overtake the operator, the operator can stop pulling on the substantially 
C-shaped member 18. This disengages drive belt 88 and engages brake band 
72 on brake dram 76. If a pushing force is applied to the lower portion of 
the substantially C-shaped member 18 by the operator or a portion of the 
operator's body, the counterclockwise pivoting of the substantially 
C-shaped member 18 causes greater braking force to be generated. 
Therefore, the mower brakes are applied upon contact with the operator's 
body, thereby preventing the mower from overtaking and injuring the 
operator. 
An alternative embodiment of a lawn mower control device 10 constructed in 
accordance with another form of the invention is shown in FIG. 5. In this 
embodiment, the pivot rods 26 are sized so as to rotate within one 
another. The right pivot rod 94 is connected to the left lever 96 in order 
to induce driving and braking forces on the left side of the lawn mower. 
Conversely, the left control assembly 14 controls the driving and braking 
of the right portion of the lawn mower. Accordingly, rotating the upper 
portion of the right control assembly 16 toward the handle 12 induces 
driving forces on the left side of the mower. This causes the mower to 
turn right if the left control assembly 14 is untouched or is pulled back. 
Accordingly, the preferred embodiments described herein provide improved 
lawn mower control devices that comply with ANSI safety standards while 
minimizing operator fatigue. Further, these embodiments provide intuitive 
mower response when actuated which lessens the likelihood of operator 
mistake and injury. In addition, these devices are relatively simple and 
rugged, thus providing excellent performance while minimizing maintenance 
costs and effort. 
While preferred embodiments have been illustrated and described, it should 
be understood that changes and modifications can be made therein without 
departing from the invention in its broader aspects. Various features of 
the invention are defined in the following claims.