Note : Les revendications sont présentées dans la langue officielle dans laquelle elles ont été soumises.
The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:
1. An improved hydrostatic control system for controlling
the output of a hydrostatic drive unit for a vehicle, the
drive unit comprising:
a pair of output pumps axially aligned, each of
the output pumps having an infinitely variable position
swash plate operatively connected thereto to control the
output of the respective pumps;
a drive motor;
cooperative means between the drive motor and
the output pumps to couple the output pumps to the drive motor;
operative means to control the output of the drive
motor; and
the improvement comprising a lost motion connecting
means provided between the swash plates of the aligned
drive pumps to operatively couple the respective outputs
of the drive pumps, such lost motion connecting means
including selective operative means to selectively control
the output of one or both pumps.
2. An improved hydrostatic control system for controlling
the output of a hydrostatic drive unit for a vehicle as
claimed in claim 1 wherein the lost motion connection
between the swash plates of the axially aligned output
pumps includes a connecting member pivotally mounted on both
pumps, the forward connecting member including an elongated
slot which permits movement of one swash plate of the
vehicle independently of the second swash plate of the vehicle.
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3. An improved hydrostatic control system for controlling
the output of a hydrostatic drive unit for a vehicle as
claimed in claim 1 or 2 wherein a dampener is disposed between
the rear swash plate and an anchor adjacent the front swash
plate of the vehicle, the dampener fully extended when the
swash plates are aligned in the neutral position and a
compression spring disposed between the rod end and the
cylinder end of the dampener to maintain the rear swash
plate in the neutral position when the dampener is fully
extended.
4. An improved hydrostatic control system for controlling
the output of a hydrostatic drive unit for a vehicle as
claimed in claim 1 wherein the operative means to control
the output of the drive motor includes a pedal linkage
arrangement cooperatively connected between a foot pedal of
the vehicle and a servo control valve controlling the
output of a cylinder which is operatively coupled to the
forward swash plate of the pair of axially aligned drive
pumps whereby activation of -the servo control valve through
the foot pedal activates the cylinder to urge the front
swash plate forward, the lost motion connection permitting
the second motor to engage when the front swash plate has
been sufficiently extended in a forward or reverse direction.
5. An improved method for controlling the output of
a hydrostatic drive unit for a front end loader, wherein
the drive unit comprises:
a pair of output pumps axially aligned, each of the
output pumps having an infinitely variable position swash
plate operatively connected thereto to control the output of
the respective pumps;
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Claim 5 continued...
a drive motor;
cooperative means between the drive motor and the
output pumps to couple the output pumps to the drive motor;
operative means including a pedal member to control
the output of the drive motor; and
the improved method comprises providing a lost
motion connecting means between the swash plates of the
aligned drive pumps to operatively couple the respective
ouptuts of the drive pumps, such lost motion connecting
means including selective operative means to selectively
control the ouptut of one or both pumps.
6. An improved method for controlling the output of
a hydrostatic drive unit for a front end loader as claimed
in claim 5 wherein providing the lost motion connection
between the swash plates of the axially aligned output
pumps includes providing a connecting member pivotally
mounted on both pumps, the forward connecting member
including an elongated slot which permits movement of one
swash plate of the vehicle independently of the second swash
plate of the vehicle.
7. An improved method for controlling the output of
a hydrostatic drive unit for a front end loader as claimed
in claims 5 or 6 wherein providing the cooperative connecting
means includes providing a dampener disposed between the
rear swash plate and an anchor adjacent the front swash
plate of the vehicle, the dampener fully extended when the
swash plates are aligned in the neutral position and a
compression spring disposed between the rod end and the
cylinder end of the dampener to maintain the rear swash
plate in the neutral position when the dampener is fully extended.
8. An improved method for controlling the output of
a hydrostatic drive unit for a front end loader as claimed
in claim 5 wherein the operative means to control the output
of the drive motor includes a pedal linkage arrangement
cooperatively connected between a foot pedal of the vehicle
and a servo control valve controlling the output of a
cylinder which is operatively coupled to the forward swash
plate of the pair of axially aligned drive pumps whereby
activation of the servo control valve through the foot
pedal activates the cylinder to urge the front swash plate
forward, the lost motion connection permitting the second
motor to engage when the front swash plate has been
sufficiently extended in a forward or reverse direction.
9. An improved hydrostatic control system for controlling
the output of a hydrostatic drive unit for a vehicle, the
drive unit comprising:
a pair of hydrostatic output pumps axially aligned,
each of the hydrostatic ouptut pumps having an infinitely
variable position swash plate mounted thereon;
a drive motor;
cooperative means between the drive motor and the
ouptut pumps to couple the output pumps to the drive motor;
operative means to control the output of the
drive motor; and
the improvement comprising a lost motion connecting
means cooperatively connected between the swash plates of
the aligned hydrostatic drive pumps, the lost motion connecting
means including a lost motion connecting member pivotally
mounted at each end to respective front and rear swash
plates of the front and rear drive pumps, the lost motion
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Claim 9 continued...
connecting member having an elongated slot in which the
connection between the front swash plate and the lost motion
connecting member is disposed, said operative means including
a servo control valve controlling the horizontal forward and
reverse output of a cylinder rigidly coupled to the frame
whereby selective control of the servo control valve controls
the output of the cylinder operatively connected to the
front swash plate of the pair of axially aligned drive
pumps, and activation of the servo control valve causes the
cylinder to rotate the front swash plate until it engages
the forward edge portion of the slot provided on the lost
motion connecting member whereupon further rotation of the
front swash plate forces rotation of the rear swash plate
to selectively couple the output of both drive pumps to the
drive motor.
10. An improved hydrostatic control system for controlling
the output of a hydrostatic drive unit for a vehicle as
claimed in claim 11 wherein the cooperative connecting means
between the aligned drive pumps includes a dampener having
a rod end and a cylinder and mounted between the rear swash
plate and an anchor mounted to the frame adjacent the front
swash plate, the dampener being fully extended when the
front and rear swash plates are disposed in a neutral
position, the dampener being compressed when the rear swash
plate is moved forwardly, and a compression spring mounted
on the dampener between the rod end and the cylinder end
of the dampener to return the rear swash plate to a neutral
position when the operative means controlling the output
of the drive motor is released.
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11. An improved hydrostatic control system for controlling
the output of a hydrostatic drive unit for a vehicle as
claimed in claim 10 wherein the operative means to control
the output of the drive motor includes a cooperative pedal
linkage disposed between the servo control valve and an
operator foot pedal for controlling the output of the drive
motor.
12. An improved method for controlling the output of
a hydrostatic drive unit for a vehicle, the drive unit
comprising:
a pair of hydrostatic output pumps axially aligned,
each of the hydrostatic output pumps having an infinitely
variable position swash plate mounted thereon;
a drive motor;
cooperative means between the drive motor and the
output pumps to couple the output pumps to the drive motor;
operative means to control the output of the
drive motor; and
the improvement comprising providing a lost motion
connecting means cooperatively connected between the swash
plates of the aligned hydrostatic drive pumps, the lost
motion connecting means including a lost motion connecting
member pivotally mounted at each end to respective front
and rear swash plates of the front and rear drive pumps,
providing the lost motion connecting means with an
elongated slot wherein which the connection between the
front swash plate and the lost motion connecting member is
disposed, said operative means including a servo control
valve controlling the horizontal forward and reverse output
of a cylinder rigidly coupled to the frame, whereby selective
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claim 12 continued..
control of the servo control valve controls the output of
the cylinder operatively connected to the front swash plate
of the pair of axially aligned drive pumps and activation
of the servo control valve causes the cylinder to rotate
the front swash plate until it engages the forward edge
portion of the slot provided on the lost motion connecting
member whereupon further rotation of the front swash plate
forces rotation of the rear swash plate to selectively
couple the output of both drive pumps to the drive motor.
13. An improved method for controlling the output of
a hydrostatic drive unit for a vehicle as claimed in claim
12 wherein the cooperative connecting means between the
aligned drive pumps is provided with a dampener having
a rod end and a cylinder end mounted between the rear
swash plate and an anchor mounted to the frame adjacent
the front swash plate, the dampener being fully extended
when the front and rear swash plates are disposed in a
neutral position, the dampener being compressed when the
rear swash plate is moved forwardly, and providing a
compression spring mounted on the dampener between the
rod end and the cylinder end of the damepener to return the
rear swash plate to a neutral position when the operative
means controlling the output of the drive motor is released.
14. An improved method for controlling the output of
a hydrostatic drive unit for a vehicle as claimed in claim
13 wherein the operative means to control the output of
the drive motor includes a cooperative pedal linkage disposed
between the servo control valve and an operator foot pedal
for controlling the output of the drive motor.
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15. A hydrostatic drive comprising:
a hydraulic motor,
two variable displacement pumps driven jointly
by a common prime mover,
conduit means connecting the outlets of both
said pumps to the inlet of said motor without intervening
valves, and
operating means for varying the displacement of
one of said pumps for operating said motor in one operating
range, and
for varying the displacement of both said pumps
simultaneously for operating said motor in another operating
range.
16. A hydrostatic drive as in claim 15 wherein said
one operating range is a lower speed range and said other
operating range is a higher speed range.
17. A hydrostatic drive as in claim 15 wherein said
operating means includes a foot pedal, and wherein said
foot pedal moves farther in operating said operating
means through said one operating range than it does in
operating said operating means through said other operating
range.
18. A hydrostatic drive as in claim 15 wherein said
operating means includes a third operating range in which
said motor operates in the reverse direction from said
other two operating ranges.
19. A hydrostatic drive as in claim 18 wherein said
operating means includes a neutral position between said
first operating range and said third operating range.
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20. A hydrostatic drive as in claim 19 wherein said
operating means includes means for selectively changing the
displacement of said one pump from either said one or said
other operating range back to neutral.
21. A hydrostatic drive as in claim 20 wherein said
other pump is returned to neutral from said other operating
range by a spring which continuously urges said other
pump toward neutral.
22. A hydrostatic drive as in claim 18 wherein reverse
drive is achieved by changing the displacement of said one
pump in the opposite sense to said first operating range.
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