Control system for outdoor power equipment

A control system for selectively actuating a component on an outdoor power equipment unit, such as a blade on a lawn mower, uses two separate and distinct operator actions to prevent inadvertent actuation. The control system includes a pivotal bail that must be pivoted from a first component disengaged position to a second component engaged position in which the bail lies flat against the handle assembly of the outdoor power equipment unit. A slide is slidably mounted on a housing, carried on one of the legs of the bail, for movement towards and away from the pivot axis of the bail. The slide must be pushed down to engage the lower end of the slide with a notch in a pivotal cam to temporarily link the cam to the bail in order to actuate the component. When the bail is released to return to its initial position, camming surfaces on the lower end of the slide and the notch are effective to mechanically cam the slide back up to its disengaged position where the lower end of the slide has disengaged the notch.

TECHNICAL FIELD 
This invention comprises a control system that uses two separate and 
distinct operator actions to selectively actuate at least one component of 
an outdoor power equipment unit. 
BACKGROUND OF THE INVENTION 
Control systems are known on rotary lawn mowers for allowing the operator 
to selectively start and stop rotation of the blade. Many of these control 
systems comprise a deadman's control carried on the handle assembly of the 
mower. Whenever the operator releases the deadman's control, the control 
moves to a blade disengaged position in which the rotation of the blade 
stops. Thus, if the operator slips and lets go of the deadman's control, 
the blade will automatically be stopped, thus preventing injury to the 
operator or to others. 
To further enhance safety, many deadman's controls require that the 
operator use two separate and distinct actions to start the rotation of 
the blade. Thus, merely squeezing the deadman's control to its blade 
engaged position using a first action or motion is insufficient to start 
blade rotation. Some other separate and distinct action must also be done 
by the operator either before or in concert with the first action. 
Requiring two separate and distinct actions of the operator to obtain 
blade rotation prevents the operator from inadvertently starting the blade 
rotation. 
U.S. Pat. No. 4,327,539 shows a lawn mower control system comprising a 
cockable deadman's control. In order to obtain blade rotation, the 
operator must first cock the deadman's control in a direction opposite to 
the direction in which the deadman's control is moved to its blade engaged 
position. Thus, the cocking action of the deadman's control comprises the 
first operator action with the subsequent movement of the deadman's 
control back in the reverse direction into the blade engaged position 
comprising the second operator action. Merely moving the deadman's control 
into its blade engaged position without first cocking it does not actuate 
the blade. 
U.S. Pat. No. 4,538,401 discloses a pivotal deadman's control for obtaining 
blade rotation. Simply pivoting the deadman's control into its blade 
engaged position does not, in and of itself, start the rotation of the 
blade. Instead, the operator first has to push down on a knob and to then 
pivot the deadman's control to obtain blade rotation. However, there is no 
automatic reset of the knob once the deadman's control is released from 
its blade disengaged position, such that subsequent blade starts could be 
obtained without having to push down on the knob again. Thus, this system 
does not meet modern safety standards which require the use of two 
separate and distinct actions before each blade start. 
Many of the control systems that are known do have system resets such that 
two actions are required after each release of the deadman's control to 
get subsequent blade starts. However, many of these systems are quite 
complex having many parts. In addition, these systems often use various 
springs and latches that must be aligned, and which must stay aligned, in 
order for the reset of the system to be properly accomplished. 
SUMMARY OF THE INVENTION 
It is one aspect of this invention to provide a two action control system 
for an outdoor power equipment unit in which the reset of the system after 
release of the deadman's control functions automatically in a foolproof 
manner. 
These and other aspects of this invention are provided by a control system 
for an outdoor power equipment unit of the type having a selectively 
actuable component. The control system comprises a first movable control 
member mounted on the unit for movement between a component disengaged 
position and a component engaged position using a first operator action. A 
second movable control member is mounted on the unit for movement between 
a component disengaged position and a component engaged position using a 
second operator action that is separate and distinct from the first 
operator action, wherein both the first and second control members must be 
moved, respectively, into their component engaged positions using the 
first and second operator actions to obtain actuation of the component. A 
means is included for mechanically camming the second movable control 
member back into its component disengaged position during movement of the 
first movable control member from its component engaged position to its 
component disengaged position.

DETAILED DESCRIPTION 
Referring to FIG. 1, an improved control system according to this invention 
is generally illustrated as 2. Control system 2 is mounted on a handle 
assembly 4 of an outdoor power equipment unit 6. As shown in FIG. 2, 
handle assembly 4 is U-shaped having two upwardly extending handle tubes 8 
joined together at their upper ends by a cross tube 10. The operator grips 
and holds onto cross tube 10 to guide outdoor power equipment unit 6 
during operation thereof. Control system 2 is located on the upper end of 
handle assembly 4 near cross tube 10 to be easily accessible to the 
operator. 
The outdoor power equipment unit 6 shown in FIG. 1 is a lawn mower 12. More 
specifically, lawn mower 12 comprises a wheeled housing 14 suited for 
movement over the ground. A rotatable cutting element comprising a blade 
16 is carried in a cutting chamber in housing 14 for severing grass or 
other vegetation at a pre-determined height above the ground. 
Control system 2 selectively actuates at least one component of lawn mower 
12, namely it selectively starts or stops rotation of blade 16. How this 
is done is unimportant to this invention and can vary depending upon the 
type of lawn mower 12 on which control system 2 is mounted. In an 
electrically powered mower, an electrical switch might be turned on and 
off by operation of control system 2 to start and stop rotation of blade 
16. In a mower 12 powered by an internal combustion engine, a clutch might 
be interposed between the drive shaft of the engine and blade 16 with the 
clutch being operated by control system 2. In any event, the nature of the 
controlled component and how that controlled component is placed into and 
out of operation is not part of this invention. Control system 2 can be 
used with any component on outdoor power equipment unit 6 which is 
desirably placed into operation using two separate and distinct actions of 
the operator. 
Moreover, it should be apparent that control system 2 is not limited for 
use with a lawn mower. There are many outdoor power equipment units having 
active components the operation of which is desirably controlled in a safe 
manner. For example, snowthrowers have rotatable snowthrowing augers and 
impellers which the operator must selectively start and stop. Control 
system 2 as disclosed herein would be as useful in controlling the 
operation of such snowthrowing augers and impellers in a snowthrower as it 
is blade 16 in lawn mower 12. Accordingly, the precise nature of outdoor 
power equipment unit 6 also forms no part of this invention. 
Control system 2 includes a pivotal deadman's control in the form of a 
U-shaped bail 20 that is pivotally carried on the upper end of handle 
assembly 4. Bail 20 includes a transversely extending cross member 22 and 
spaced downwardly extending legs 24. Each bail leg 24 has an outwardly 
turned lower end 26 that serves as a pivot shaft for bail 20. Each lower 
end 26 of each leg 24 of bail 20 is pivotally received in a hole 28 on the 
adjacent handle tube 8. See FIG. 9. 
Overall, bail 20 has a shape that is very similar to the shape of the upper 
portion of handle assembly 4. For example, when bail 20 is pivoted flat to 
lie against handle assembly 4, the transverse cross member 22 of bail 20 
will lie adjacent the cross tube 10 of handle assembly 4 so that the 
operator's hands can grip both bail 20 and handle assembly 4 at the same 
time. 
Bail 20 is normally maintained in a blade disengaged position as shown in 
solid lines in FIGS. 1 and 2 in which the transverse cross member 22 of 
bail 20 is spaced forwardly in front of cross tube 10 of handle assembly 
4. When it is desired to obtain blade rotation, bail 20 has to be pivoted 
out of this blade disengaged position and into a blade engaged position in 
which bail 20 has been pivoted flat against handle assembly 4 and cross 
member 22 of bail 20 lies adjacent cross tube 10 of handle assembly 4. 
Thus, referring to FIG. 1, to obtain blade rotation, the operator has to 
pivot bail 20 in a clockwise direction from the solid line position in the 
direction of the arrow A. This pivoting motion of bail 20 out of its blade 
disengaged position and towards its blade engaged position is the first 
action of the operator that is needed to obtain blade rotation. 
However, pivoting bail 20 as just described is itself insufficient to 
obtain blade rotation. Control system 2 includes a control cable 30 that 
must be pulled by bail 20 in order to obtain blade rotation with the lower 
end of control cable 30 being attached to the electric switch or clutch 
that begins blade rotation. But, control cable 30 is not itself directly 
attached to or operatively connected to bail 20. Instead, the upper end of 
control cable 30 is connected to a second pivotal member comprising a 
pivotal cam 32 that is independent of and which is rotatably journalled on 
the outturned lower end 26 of one of the legs 24 of bail 20. For control 
cable 30 to be pulled, pivotal cam 32 must be somehow linked to bail 20 
such that rotation of bail 20 is also effective to rotate pivotal cam 32. 
That linking function is performed by a slide 34 that can be selectively 
pushed inwardly to temporarily link pivotal cam 32 to bail 20. This inward 
push on slide 34 is the second operator action which must occur in order 
to obtain blade rotation. 
Bail 20 includes a housing 36 which captures and holds slide 34 when 
control system 2 is fully assembled. Housing 36 is shaped to be 
non-rotatably carried on a U-shaped bend 38 on one leg 24 of bail 20 such 
that housing 36 is carried with bail 20 during its pivoting movement. For 
example, the upper portion 40 of U-shaped bend 38 in bail leg 24 rests in 
an upwardly facing, concave trough 42 in housing 36 when housing 36 is 
installed on bail leg 24 with the outturned lower end 26 of bail leg 24 
passing through a central hub 44 of housing 36. Thus, housing 36 is 
effectively captured on bail 20 for joint movement therewith. 
Slide 34 is mounted for a vertical up and down motion on housing 36, i.e. a 
motion towards and away from the pivot axis of bail 20. Referring to FIG. 
9, housing 36 includes a horizontally extending pin 46 that is received in 
a vertical slot 48 in slide 34 with a bolt 50 being threaded into a bore 
in pin 46 to hold slide 34 in place on housing 36. However, bolt 50 does 
not firmly clamp slide 34 on housing 36, but instead only loosely secures 
slide 34 to housing 36. Slide 34 must be free to move up and down on 
housing 36 over the range of motion provided by slot 48. A biasing spring 
52 extends between the top of pin 46 and the underside of an upper 
internal surface on slide 34. Thus, biasing spring 52 normally exerts an 
upward force on slide 34, tending to bias slide 34 to its upper, blade 
disengaged position on housing 36 where the lower end of slot 48 engages 
pin 46. See FIG. 6. 
In addition to being captured on pin 46, slide 34 has various surfaces that 
engage with portions of housing 36 to facilitate smooth up and down motion 
of slide 34. For example, referring to FIG. 7, the back 54 of slide 34 is 
a planar surface that abuts against a planar internal guide surface 56 on 
housing 36. The front of slide 34 extends up above back 54 to form an 
extended lip 58. This lip 58 abuts against and slides on the upper portion 
40 of U-shaped bend 38 in bail leg 24. In addition, lip 58 includes a rear 
shoulder 60 that abuts against the bottom of the upper portion 40 of 
U-shaped bend 38 in bail leg 24 when slide 34 is in its upper position. 
The front of slide 34 includes a recess 62 that is shaped to receive an 
operator's thumb therein. This helps the operator to engage and push down 
on slide 34 when desired to selectively engage or couple slide 34 to 
pivotal cam 32. As noted earlier, this pushing or sliding action of slide 
34 is the second operator action that is required to obtain blade 
rotation, which action is separate and distinct from the pivoting action 
needed to rotate bail 20. 
The manner in which slide 34 engages or is coupled to pivotal cam 32 is 
noteworthy. Pivotal cam 32 includes a notch 64 in the upper edge thereof 
which includes a rear, generally vertical surface 66 that is generally 
perpendicular to the direction of rotation of bail 20, a bottom base 
surface 68, and a forward, inclined camming surface 70. The bottom of 
slide 34 is formed with a complementary set of surfaces. In other words, 
the bottom of slide 34 also includes a forward, inclined camming surface 
70', a flat bottom base surface 68', and an upwardly extending rear 
surface 66' that is simply the lower end of the back 54 of slide 34. When 
slide 34 is pushed down, the complementary surfaces 66, 68 and 70 on slide 
34 and pivotal cam 32 can, at times, be brought into a mating engagement. 
When this occurs, bail 20 is then rotationally linked to pivotal cam 32 as 
the rotation of bail 20 will be transmitted through the vertical rear 
surface 66' of slide 34 to the vertical rear surface 66 of notch 64 to 
push against and now rotate pivotal cam 32. 
A torsion spring 72 is used to bias bail 20 into its blade disengaged 
position. Torsion spring 72 is received inside housing 36 in an annular 
recess 74 with one end 76 of spring 72 being received against a lip 78 in 
housing 36. The other end 80 of spring 72 extends through an arcuate slot 
82 in pivotal cam 32 to be received in a small hole 84 in the adjacent 
handle tube 8 of handle assembly 4. When bail 20 rotates clockwise about 
its pivot point towards its blade engaged position as indicated by the 
arrow A in FIG. 1, the lip 78 pushes against the inner end 76 of torsion 
spring 72 to tension spring 72. When bail 20 is released by the operator, 
the tension in torsion spring 72 helps move bail 20 back to its blade 
disengaged position. 
Torsion spring 72 is effective to only move or act on bail 20. A separate 
biasing means acts on pivotal cam 32, namely the spring force (not shown) 
that is normally associated with control cable 30. When pivotal cam 32 is 
rotated by bail 20 to pull on control cable 30, this rotation acts against 
the spring force that is normally present on cable 30. When bail 20 is 
released, the cable spring force rotates pivotal cam 32 back to its 
initial position. 
Pivotal cam 32 includes means for limiting the rotation thereof to a 
predetermined amount. This rotation limiting means includes a stop 86 
having first and second surfaces 88 and 90, respectively. In the initial 
position of pivotal cam 32 as shown in FIG. 6 or 7, namely the position in 
which control cable 30 has not been pulled, stop surface 88 engages 
against the underside of the adjacent handle tube 8. In the second rotated 
position of pivotal cam 32 as shown in FIG. 8, namely the position in 
which control cable 30 has been pulled, the other surface 90 will be 
brought adjacent the underside of handle tube 8 at about the same time as 
the cross member 22 of bail 20 abuts or nests up against cross tube 10 of 
handle assembly 4. However, cross member 22 of bail 20 preferably engages 
cross tube 10 first to arrest the rotation of bail 20 slightly before 
surface 90 would have engaged handle tube 8 so that surface 90 is not 
technically itself a stop surface. The surfaces 88 and 90 are spaced apart 
relative to one another a distance slightly less than 90.degree.. This is 
also the distance of arcuate slot 82 since pivotal cam 32 has to be able 
to move past the fixed end 80 of torsion spring 72 during its pivotal 
motion. 
Bail 20 is arranged for a pivoting motion that is somewhat greater than the 
pivotal motion of pivotal cam 32. In other words, bail 20 has a total 
range of angular motion that exceeds that of pivotal cam 32 by some 
10.degree. to 20.degree.. This permitted overtravel of bail 20 compared 
with the travel of pivotal cam 32 is effective in conjunction with the 
camming surfaces 70 in mechanically camming or returning slide 34 from its 
lower position to its upper position. This will be understood and 
appreciated more clearly after considering the following operational 
description of control system 2. 
The initial disengaged position of control system 2 is shown in FIG. 6. In 
this position, slide 34 is biased by spring 52 into its upper, blade 
disengaged position. If the operator grabs and rotates bail 20 in a 
clockwise direction until bail 20 lies flat against handle assembly 4, but 
does not first push on slide 34, the slide 34 and housing 36 simply rotate 
around the upper edge of pivotal cam 32 without rotating cam 32. In other 
words, while bail 20 and its associated components are pivoted into their 
phantom line position in FIG. 6, pivotal cam 32 never leaves its solid 
line position and control cable 30 is not pulled on. Thus, blade 16 does 
not start rotating. 
During this rotation of bail 20, torsion spring 72 is tensioned. Thus, when 
bail 20 is released, torsion spring 72 will return bail 20 from the 
phantom line position to the solid line position in FIG. 6. Again, bail 20 
and its associated components simply pivot back around the stationary cam 
32 which was never moved in the first place. Thus, if the operator never 
engages slide 34, bail 20 can be rotated back and forth between its solid 
and phantom line positions shown in FIG. 6 any number of times without 
ever moving cam 32 or obtaining rotation of blade 16. 
To obtain blade rotation, the operator must push down on slide 34 during 
the initial phase of rotation of bail 20, i.e. in the first 20.degree. or 
so of rotation. When the operator uses this second operator action, i.e. 
the downward push on slide 34, this will cause the surfaces 66', 68' and 
70' formed on the bottom of slide 34 to be engaged with those 
complementary surfaces 66, 68 and 70 of notch 64 on the upper edge of 
pivotal cam 32. In other words, the bottom of slide 34 drops down into 
notch 64 when the operator pushes down on slide 34. Then, the first 
operator action comprising the rotation of bail 20 by the operator will be 
effective in rotating pivotal cam 32 along with bail 20 due to the 
abutting engagement between the rear surfaces 66 in the sets of 
complementary surfaces. Thus, as bail 20 is pivoted towards its blade 
engaged position, it now carries pivotal cam 32 around with it, thereby 
pulling on control cable 30. This pull on control cable 30 is effective to 
actuate the controlled component on outdoor power equipment unit 6, namely 
it starts the rotation of blade 16. 
Once the bottom of slide 34 drops down into notch 64, spring 52 will be 
ineffective in causing it to move out of engagement. The complementary 
mating surfaces on notch 64 exert sufficient pressure on slide 64 to keep 
slide 64 in its lower, blade engaged position. Thus, the operator does not 
have to continually keep pushing down on slide 64, but need do so only 
until slide 34 is engaged in notch 64 and rotation of bail 20 has 
continued on towards its blade engaged position. 
When the operator desires to stop the rotation of blade 16, all he or she 
must do is to release bail 20 from its blade engaged position in which 
bail 20 lies flat against handle assembly 4. Torsion spring 72 acting on 
bail 20 will now pivot bail 20 back to its blade disengaged position as 
depicted by the arrow B in FIG. 1, and the spring force acting on control 
cable 30 will pivot pivotal cam 32 back to its initial position. 
However, pivotal cam 32 will reach its initial position, i.e. the position 
where the stop surface 88 has engaged the underside of handle tube 8, 
before bail 20 reaches its blade disengaged position. Remember that bail 
20 has an additional 10.degree. to 20.degree. of motion as compared to 
that of pivotal cam 32. In this last portion of bail movement, i.e. in the 
overtravel of bail 20 past pivotal cam 32, relative motion will occur 
between bail 20 and pivotal cam 32, causing the camming surfaces 70 to 
slide on one another. This sliding of the camming surfaces 70 will 
mechanically move or cam slide 34 out of its lower engaged position and 
automatically reset it to its upper disengaged position. Thus, even if 
spring 52 were to fail, the mechanical camming action imposed on slide 34 
by this control system arrangement will be effective to always disengage 
bail 20 from pivotal cam 32 as bail 20 returns to its blade disengaged 
position. 
It should be apparent that a consequence of the camming action is a 
foolproof resetting of slide 34 into its upper blade disengaged position. 
This ensures that two separate are distinct actions are always required to 
obtain subsequent blade operations, i.e. the push down on slide 34 along 
with the separate pivoting of bail 20. It ensures that slide 34 will not 
be jammed or somehow kept in its blade engaged lower position, thus 
preserving the safety aspects of the two separate and distinct actions of 
control system 2. Accordingly, control system 2 of this invention will be 
more reliable in operation than many known systems and thus safer to use. 
Another advantage of control system 2 is its intuitive method of operation 
and ease of use. The thumb receiving recess 62 invites the operator to 
push down on slide 34 so that the operator will intuitively understand 
that slide 34 needs to be pushed down. Slide 34, slide housing 36 and 
pivotal cam 32 are all simply mounted on one of the bail legs 24 beneath 
cross member 22 without obstructing cross member 22 or unduly cluttering 
bail 20. Moreover, pushing down on slide 34 serves to directly engage the 
bottom of slide 34 in notch 64 to couple bail 20 to pivotal cam 32. Thus, 
no complicated and extended linkage is required to accomplish this 
coupling function such that long link arms, biasing springs and the like 
can be dispensed with. Accordingly, control system 2 according to this 
invention is durable and reliable in operation. 
When bail 20 is in its normal component disengaged position as shown in 
FIG. 6, it would be possible to rotate bail 20 forwardly out of this 
position. This forward rotation would be transmitted by the bottom of 
slide 34 to pivotal cam 32 since the front edge of camming surface 70 
still engages with the bottom of slide 34 even in the upper, component 
disengaged position of slide 34. Stop surface 88 on stop 86 engages the 
bottom of handle tube 8 to prevent this forward rotation of cam 32 and to 
keep the parts in their usual orientation of FIG. 6. If enough force is 
applied to bail 20 to force stop 86 past handle tube 8 during this 
unintended forward rotation of bail 20 out of its component disengaged 
position, the control system 2 will disassemble itself, i.e. the outwardly 
turned legs 26 on bail 20 will disengage from handle tubes 8, before cam 
32 can be rotated far enough to actuate cable 30. 
While pivotal cam 32 has been shown as pulling on a Bowden type control 
cable 30 to actuate the controlled component, other arrangements are 
possible. For example, pivotal cam 32 might act directly on the contacts 
of an electrical switch mounted on handle tube 8 with the switch being 
open in the initial FIG. 6 position of pivotal cam 32 and the switch being 
closed in the rotated FIG. 8 position of pivotal cam 32. In such a case, 
control cable 30 would be dispensed with although some means for biasing 
pivotal cam 32 back to its initial position would then be needed, e.g. an 
additional spring. 
Various other modifications will be apparent to those skilled in the art. 
For example, a second control cable similar to cable 30 could be added to 
control system extending between some portion of bail 20 and a traction 
drive (not shown) on lawn mower. This would provide single action 
actuation of the traction drive simply by pivoting bail 20, with two 
actions still being required to obtain rotation of blade 16. Accordingly, 
the scope of this invention is to be limited only the appended claims.