MECANISME DE COMMANDE POUR FREIN ET EMBRAYAGE D'UNE PRISE DE FORCE

POWER TAKE-OFF BRAKE AND CLUTCH ACTUATION ASSEMBLY

Abrégé anglais

POWER TAKE-OFF BRAKE AND CLUTCH ACTUATION ASSEMBLY
Abstract of the Disclosure
A control lever communicates with a plurality of additional
levers and an electrical circuit. A PTO brake and electric
clutch are responsive to the control lever and circuit for
engagement and disengagement. The linkage system includes an
electrically responsive inductor and magnetically responsive
plate. When the PTO brake is disengaged and the clutch is
engaged, the electrical circuit supplies current to the inductor
which creates a magnetic field to capture the plate holding the
brake and clutch in their respective modes. Upon actuation of
the control lever or full application of an associated vehicle's
wheel brakes, the circuit is disrupted to the inductor allowing
a spring to act upon the linkage assembly to engage the PTO
brake and causing the PTO clutch to be disengaged.

Revendications

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:
1. A PTO brake-clutch actuation system for a tractor
having a plurality of walls, an operator's station, a PTO shaft,
said actuation system being mounted to said plurality of walls,
operatively communicating with said PTO brake and current
responsive clutch and being operator actuated from said
operator's station, said actuation system comprising:
an actuation lever pivotally mounted at a point along its
length to one of said tractor walls such that one end of said
actuation lever extends into the operator station;
said PTO brake having a brake band displaceable between
first and second positions and fixably mounted at one end to one
of said tractor walls;
a brake lever having one end fixably mounted to the other
end of said brake band and being pivotally mounted at a point
therealong to said tractor walls;
linkage means for communicating motion of said actuation
lever to the other end of said brake lever, said linkage means
including biasing means for biasing said lever such that said
brake band assumes and maintains said second position;
magnetic means for communicating with said linkage means to
overcome said biasing means such that said brake band can assume
selectively and maintain said first position in response to
electrical current delivered to said magnetic means; and
circuit means for directing electrical current to said
magnetic means and said current responsive clutch.
2. A PTO brake-clutch actuation system as claimed in claim
1 wherein said linkage means comprises:
a bell crank pivotally mounted to another one of said
tractor walls having first and second arms;
a rod having one end swivelly mounted to said second arm of
said bell crank;
a slide link pivotally mounted at one end to another one of
said tractor walls, having an apertured forward portion oriented
generally perpendicular to and slidably receiving said rod;
a stop member fixably mounted to said rod;
a spring placed around said rod and held in compression
between said forward portion of said slide link and said stop
member;
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a second end of said rod being fixably mounted to said other
end of said brake lever; and
communication means for communicating pivotal motion of said
actuation lever to said bell crank such that said bell crank
will pivot in response thereto.
3. A PTO brake-clutch actuation system as claimed in claim
2 wherein said communication means comprises:
a generally U-shaped lever pivotally mounted at one end to
one of said tractor walls;
a travel link pivotally mounted to said actuation lever at
one end and said U-shaped lever at the other end; and
a link pivotally mounted at one end at a point along said U-
shaped lever and pivotally mounted at its other end to said
first arm of said bell crank,
4. A PTO brake-clutch actuation system as claimed in claim
1 wherein said magnetic means comprises:
an inductor current means responsive to create a magnetic
field fixably mounted to one of said tractor walls;
a generally U-shaped lever pivotally mounted at one end to
one of said tractor walls;
a travel link pivotally mounted to said actuation lever at
one end and said U-shaped lever at the other end;
a link pivotally mounted in the proximity of one end to said
U-shaped lever and pivotally mounted at its other end to said
first arm of said bell crank; and
a plate fixably mounted to one end of said link such that
pivotal displacement of said U-shaped lever brings said plate
into abutting relationship to said inductor current means or
places said plate remote to said inductor current means.
5. A PTO brake-clutch actuation system as claimed in claim
1, wherein said circuit means comprises:
a brace fixably mounted to one of said tractor walls;
a first normally on PTO switch fixably mounted to said brace
such that said brake lever is biased against said first PTO
switch placing said first PTO switch in an "OFF" position when
said actuation lever is in a first position;
a current source;
means for delivering current from said current source to
said PTO switch;
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means for delivering current from said PTO switch to said
clutch; and
means for delivering current from said current source to
said magnetic means.
6. A PTO brake-clutch actuation system as claimed in claim
5, wherein said current delivery means to said magnetic means
comprises:
said vehicle having a first and second vehicle brake pedal;
a third normally closed switch;
a fourth normally closed switch;
said third and fourth switches fixably mounted in said
vehicle such that they are fully open only when said vehicle
brake pedals are fully depressed;
means for communicating said third and fourth switches in
parallel; and
means for delivering current to said PTO switch from said
current source and from said third and fourth switches to said
magnetic means.
7. A PTO brake-clutch actuation system for a tractor
having a plurality of walls, an operator's station, a PTO shaft,
and a PTO brake and current responsive clutch for said PTO
shaft, said actuation system being mounted to said plurality of
walls, operatively communicating with said PTO brake and current
responsive clutch and being operator actuated from said
operator's station, said actuation system comprising:
an actuation lever pivotally mounted at a point along its
length to one of said tractor walls such that one end of said
actuation lever extends into said tractor's operator station;
said PTO brake having a brake band displaceable between
first and second positions and fixably mounted at one end to one
of said tractor walls;
a brake lever having the other end of said brake band
fixably mounted thereto, said brake lever being pivotably
mounted to one of said tractor walls;
linkage means for communicating motion of said actuation
lever to said brake lever, said linkage means comprising:
a bell crank having first and second arms pivotally mounted
to another one of said tractor walls, said arms having a
generally perpendicular orientation;
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a rod having one end swivelly mounted at one end to said
second arm of said bell crank;
a slide link pivotally mounted at one end to another one of
said tractor walls, having a forward portion oriented generally
perpendicular to said rod and containing an aperture therein,
said rod extending into and beyond said aperture;
a stop member fixably mounted to said rod;
a spring placed around said rod and held in compression
between said forward portion of said slide link and said stop
member;
a second end of said rod being fixably mounted to said brake
lever;
communication means for communicating pivotal motion of said
actuation lever to said bell crank such that said bell crank
will pivot in response thereto;
magnetic means for communicating with said linkage means to
overcome said spring such that said brake band can selectively
assume and maintain said first position in response to
electrical current delivered to said magnetic means; and
circuit means for directing electric current to said
magnetic means and said current responsive clutch.
8. A PTO brake-clutch actuation system as claimed in claim
7 wherein said magnetic means comprises:
an inductor current means responsive to create a magnetic
field fixably mounted to another one of said tractor walls; and
a plate fixably mounted to and movable with said
communication means such that pivotal displacement of said lever
brings said plate into abutting relationship to said inductor
current means or placing said plate remote to said inductor
current means.
9. A PTO brake-clutch actuation system as claimed in claim
7 wherein said circuit means comprises:
a brace fixably mounted to one of said tractor walls;
a first normally on PTO switch fixably mounted to said brace
such that said lever is biased against said first PTO switch
placing said PTO switch in an "OFF" position when said actuation
lever is in a first position;
a current source;
means for delivering current from said current source to
said PTO switch;
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means for delivering current from said PTO switch to said
clutch; and
means for delivering current from said current source to
said magnetic means.
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Description

PO~ER TAKE-OFF BRP~KE AND CLUTCH ACTUATION ASSEMBLY
Background of the Invention
This invention relates to tractor power take-off assemblies
and, more particularl~, to power take-off brake and clutch
actuation assemblies.
It is known to provide a tractor mounted power take-off
(PTO) assembly with a brake assembly cooperatively acting
through an actuation assembly with a PTO clutch assembly.
Collectively, one of the main purposes of such assemblies is to
reduce the stopping time associated with disengagement of the
PTO assembly as evidenced by U. S. Patent No. 3,831,722. Such
assemblies have achieved a modicum of success in reducing PTO
stopping time as compared to PTO assemblies not so equipped with
a PTO brake. However, it is desirable to further decrease the
PTO stopping time. It is additionally desirable to enable the
actuation assembly to be responsive to an operator encountered
panic situation.
Summary of the Invention
It is an objective of the present invention to present a PTO
brake and clutch actuation assembly which exhibits substantially
shortened stopping time.
It is a further objective of the present invention to
present a PTO actuation system which can automatically respond
to a vehicle operator's reaction to the presentation of a panic
situation~
The PTO actuation system includes a control lever
communicating with a linkage assembly and an electric circuit
responsible to engaging and disengaging the brake-clutch
assembly. The control lever acts upon the linkage assembly such
that displacement of said control lever causes a magnetically
responsive plate to be positionable in either a first or second
position. When the plate is in a second position, the plate is
within the magnetic field of influence of an electrically
responsive inductor. The linkage assembly is also in
communication with a spring biased brake applied linkage
arrangement. The magnetic influence on the plate is sufficient
to overcome the spring biasing force to cause the linkage to
assume and maintain a brake disengage position.
When the plate is in the secona position, a band brake is
disengaged, bringing the linkage arrangement into contact wit~ a
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first and second switch placing the switches in an "ON"
condition. When the switches are in an "ON" condition,
electrical current is supplied through a circuit to an inductor
and a PTO electric clutch, placing the inductor and the clutch
in an "ON" condition representing a PTO engaged condition.
Should a vehicle operator instigate a full vehicle brake applied
condition, current is disrupted to the inductor by the circuit
allowing the linkage spring to bias the PTO brake "ON" and
placing the switches in an "OFF" condition. As a result, the
PTO clutch is turned "OFFn.
Brief Description of the Drawings
FIG. 1 is a sectioned side elevated view of a PTO clutch and
brake actuation assembly in accordance with the present
invention.
FIG. 2 is a top view of a portion of the PTO brake and
clutch actuation assembly.
FIG. 3 is a top view of the portion of the PTO brake and
clutch actuation assembly in a second position.
FIG. 4 is a schematic view of an electrical control circuit
in accordance with the present invention.
Description of the Pre~erred Embodiment
Referring to FIGS. 1 and 2, a vehicle console, generally
indicated as 11, has a power take-off control lever 13 extending
into the console through a slot (not shown). A mounting brace
15 of conventional design is fixably mounted by any conventional
means to and beneath the console 11 to pivotably maintain the
PTO lever 13 at "A" in a conventional manner. The lever 13
further extends beneath the console 11 and is received within a
slot (not shown) on a lower support plate 17. The slots in the
console 11 and lower support plate 17 serve to confine the
travel of control lever 11 to a generally Z-path in a
conventional manner. An adjustable travel link 19 is pivotally
mounted to the PTO lever 13 at one end by any conventional means
such as by a retaining pin and to a Eirst generally U-shaped
lever arm 21 at the other end in a conventional manner such as
by a ball joint arrangement. A spring 13a is anchored between
lever 13 and a sidewall of the tractor and normally biases the
lever to one side of the Z-path. The lever arm 21 is in turn
fixably mounted by any conventional means to a pivot cylinder 23
pivotably by any conventional means on a shaft 26 extending
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1 between support plates 17 and 27 and fixably mounted thereto. A
second lever 25 is also fixably mounted by any conventional
means to pivot cylinder 23. The support pla~es 17 and 27 are
mounted in the vehicle (not shown) in any of a variety of
conventional manners.
An electrically responsive magnetic inductor 29 is fi~ably
mounted on one end of a pin 31 extending through a seat 33
formed in a vehicle support wall 35. A nut 39 is threadably
mounted to the other end of pin 31. A magnetically responsive
plate ~1 is fixably mounted by any conventional means to the end
of a link 43. The link 43 is pivotably mounted by any
conventional means such as by a pin 45 between the first and
second levers 21 and 25 respectively. The other end of link 43
is pivotably ~ounted by any conventional means such as by a pin
47 between one arm 49 of a bell crank 51 and a link 53. Link 53
and bell crank 51 are keyed to a pivot cylinder 55 pivotably
mounted around a shaft 57 fixably mounted by any conventional
means between plates 17 and 27. Arm 49 and link 53 thus form
first and second arms of the bell crank and motion of PTO lever
13 is transferred to the bell crank via a communication means
which, in the preferred embodiment includes the travel link 19,
lever arm 21 and link 43.
A band brake and electric clutch assembly 59 of conventional
design is mounted in a conventional manner around PTO shaft 61
and between opposite arms 63 (only one shown~ of a support plate
65 in any conventional manner. The support plate 65 is fixably
mounted by any conventional means to a vehicle wall 67. A
linkage assembly 69 communicates the arm of bell crank 51 to the
band brake and clutch assembly 59. Linkage assembly 69 includes
a rod 71. The rod 71 is threadably received in a link 73 having
a stop 75. A swivel link 77 is mounted in a seat 79 of link 73
in a conventional manner. The swivel link 77 is also fixably
mounted to arm 81 of bell crank 51 in a conventional manner such
as with a nut. A portion of rod 71 is slidably received through
a slide link 83 which is pivotably mounted at one end by any
conventional means to the support plate 63. The other end of
rod 71 journeys slidably into and beyond a transverse pin 85
carried by one end of a lever 93. A plurality of threadably
mounted nuts 87 and 89 around rod 71 capture the transverse pin
85 therebetween. A spring 91 is placed around the rod 71 and is
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biased in compression at one end by stop 75 and by the slide
link 83 at its other end.
Lever 93 is pivotably mounted to the support plate 65 at l'B
by any conventional means. A brake band 95 is secured to a post
97 formed at the other end of lever 93 and the other end of
brake band 95 is secured to a post 97 ~ormed in support plate
63, such that the brake band 95 extends around braking surface
99. General linear motion of rod 71 causes the lever 93 to
pivot resulting in the tightening or loosening of brake band 95
around the braking surface 99 to correspond to an engaged or
disengaged condition. The lever 93 has a landing 101 which is
biased against electric switches 103 and 105 when the brake band
95 is in a disengaged position. Switch 105 is hidden behind
switch 103 in FIG. 1, but is shown in FIG, 4.
Referring now to FIGS. 1 and 3, should the PTO lever 13 be
manually displaced so the lower end moves away from the wall 35,
the travel link 19 causes the links 21 and 25 to pivot
displacing link 43. The displacement of link 43 causes plate 41
to separate from inductor 29. The displacement of link 43
further causes bell crank 51 and link 53 to pivot and draw link
73 and rod 71 to the left, thereby pivoting lever 93 which
tightens brake band 95 to assume a brake applied position and
places switches 103 and 105 in an "OFF" condition interrupting
current flow through a circuit 111 (described subsequently) to
disengage electric clutch 107. The bias of spring 91 maintains
a brake applied condition. When lever 13 is returned to its
original position, lever 93 is pivoted back into contact with
switches 103 and 105, placing the switches in an "ON" state.
Current can again be directed through circuit 111 to electric
clutch 107 for engagement. Brake band 95 is also placed in a
slack or released condition. The magnetic force on plate ~1 by
inductor 29 in this lever 13 position is sufficient to overcome
the biasing force oE spring 91 allowing the PTO system to remain
"ON".
Referring now to FIG. 4, the circuit 111 includes a double
switch 113 having an off, run and start position. When the
switch 113 is placed in the start position, current is delivered
to a transmission switch 115 requiring that the vehicle
transmission (not shown~ be placed in neutral to allow current
to be transmitted therethrough. Current is then delivered from
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the transmission switch 115 through diodes 117 and 119 to a coil
switch 121 and a coil switch 123 closing the coil switches.
Current is also delivered to coil switches 121 and 123 through
seat switch 125 and time delay 127. Current is further
delivered through diode 129 to the vehicle engine ignition coil
(not shown) allowing the vehicle to attain a start mode. During
the start-up phase, the PTO switches 103 and 105 are set in the
''OFFI' position by lever 13.
When the switch 113 is placed in the run position, current
is delivered through coil switch 123 to the engine coil and is
delivered through coil switch 121 to an auxiliary PTO switch
131. The auxiliary P~O switch 131 controls a conventional
electric clutch 133. The inclusion of switch 131 and clutch 133
allow the circuit 111 to be employed on those tractors which
include a conventional auxiliary PTO system as an option. Power
is delivered through two brake switches 135 and 137 communicated
in parallel to magnetic inductor 29. The brake switches 135 and
137 are conventionally normally closed contact switches. The
switches 135 and 137 are placed in proximity to the vehicle's
brake pedals (not shown) in a conventional manner such that a
respective switch is open only when the associated brake pedal
is fully depressed. As a result, current to the magnetic
inductor 29 is only interrupted when both vehicle brake pedals
are fully depressed.
It is observed that should the brake band 95 be placed in
the engaged position (B-on), PTO switch 103 is placed in an
"OFF" position to disrupt current to and thereby disengage PTO
clutch 107 (represented in FIG. ~ as inductance 107) and PTO
switch 105 is also in the "OFF~ position. Further, should the
brake band be placed in the disengaged position (B-off), PTO
switch 103 is placed in the "ON" position to allow current to
and thereby engage PTO clutch 107 and PTO switch 105 is placed
in an open position. Should a panic situation arise, the
depression of the vehicle brakes to a maximum position will open
both switches 135 and 137 disrupting flow to magnetic inductor
29 causing the spring 91 to apply the brake band and close
switch 103 to disengage the clutch 107.
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