U.S. patent application number 10/604904 was filed with the patent office on 2004-06-17 for braking arrangement and braking maneuver means.
This patent application is currently assigned to VOLVO WHEEL LOADERS AB. Invention is credited to CARLSSON, Sven-Ake, VIGHOLM, Bo.
Application Number | 20040112696 10/604904 |
Document ID | / |
Family ID | 20411291 |
Filed Date | 2004-06-17 |
United States Patent
Application |
20040112696 |
Kind Code |
A1 |
CARLSSON, Sven-Ake ; et
al. |
June 17, 2004 |
BRAKING ARRANGEMENT AND BRAKING MANEUVER MEANS
Abstract
Brake-operating assembly for a machine including first and
second brake pedals that are interconnected with one another. A
first valve element is connected to the first brake pedal and
arranged to control flow of hydraulic fluid from a pressure source
to brake cylinders of the machine. A second valve element is
connected to the second brake pedal and arranged to control flow of
hydraulic fluid from the pressure source to the brake cylinders of
the machine. The interconnection between the first and the second
brake pedals is established utilizing at least one connecting line
arranged between the first and the second valve element for
hydraulic fluid.
Inventors: |
CARLSSON, Sven-Ake;
(Eskilstuna, SE) ; VIGHOLM, Bo; (Eskilstuna,
SE) |
Correspondence
Address: |
TRACY W. DRUCE, ESQ.
1496 EVANS FARM DR
MCLEAN
VA
22101
US
|
Assignee: |
VOLVO WHEEL LOADERS AB
S-631 85
Eskilstuna
SE
|
Family ID: |
20411291 |
Appl. No.: |
10/604904 |
Filed: |
August 26, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10604904 |
Aug 26, 2003 |
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09711668 |
Nov 13, 2000 |
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6619460 |
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09711668 |
Nov 13, 2000 |
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PCT/SE99/00797 |
May 11, 1999 |
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Current U.S.
Class: |
188/361 |
Current CPC
Class: |
F16H 63/48 20130101;
B60T 1/005 20130101; F16D 59/02 20130101; F16D 49/00 20130101; F16D
63/006 20130101; B60T 13/22 20130101; Y10T 74/19637 20150115; F16H
3/093 20130101; F16H 63/3483 20130101 |
Class at
Publication: |
188/361 |
International
Class: |
B60T 011/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 13, 1998 |
SE |
9801672-8 |
Claims
1. A brake-operating assembly for a machine comprising: a first and
a second brake pedal which are interconnected with one another, and
a first valve element which, is connected to the first brake pedal
and is arranged so as to control the flow of hydraulic fluid from a
pressure source to brake cylinders of the machine, wherein a second
valve element is connected to the second brake pedal and is a
arranged so as to control the flow of hydraulic fluid from the
pressure source to the brake cylinders of the machine, and in that
the connection between the first and the second brake pedal
consists of at least one connecting line for hydraulic fluid
arranged between the first and the second valve element.
2. The brake-operating assembly as recited in claim 1, wherein a
shuttle valve is arranged in the connecting line, which shuttle
valve closes the connection between the second valve element and
the brake cylinders when the first valve element is activated by
the first brake pedal.
3. The brake-operating assembly as recited in claim 1, wherein a
shuttle valve is arranged in a first brake line that is connected
to the brake cylinders that are located on a first wheel axle of
the machine.
4. The brake-operating assembly as recited in claim 1, wherein the
first valve element comprises a first and a second slide valve
which are arranged in such a manner that the first slide valve
controls the second slide valve when the first slide valve is
activated by the first brake pedal.
5. The brake-operating assembly as recited in claim 4, wherein the
first slide valve is connected to the shuttle valve, and in that
the second slide valve is connected via a second brake line to the
brake cylinders which are located on a second wheel axle of the
machine.
6. The brake-operating assembly as recited in claim 1, wherein a
pilot line for hydraulic fluid is arranged between the first and
the second valve element so that when the second valve element is
activated by the second brake pedal, the first valve element will
be activated by the hydraulic fluid in the pilot line.
7. A brake-operating assembly for a machine, said assembly
comprising: a first second brake pedal and a second brake pedal
that are interconnected with one another; a first valve element
connected to the first brake pedal and arranged to control flow of
hydraulic fluid from a pressure source to brake cylinders of the
machine; a second valve element connected to the second brake pedal
and arranged to control flow of hydraulic fluid from the pressure
source to the brake cylinders of the machine; and the
interconnection between the first and the second brake pedals
comprising at least one connecting line arranged between the first
and the second valve element for hydraulic fluid.
8. The brake-operating assembly as recited in claim 7, further
comprising: a shuttle valve arranged in the connecting line, said
shuttle valve being adapted to close the connection between the
second valve element and the brake cylinders when the first valve
element is activated by the first brake pedal.
9. The brake-operating assembly as recited in claim 8, wherein the
shuttle valve is arranged in a first brake line that is connected
to the brake cylinders which are located on a first wheel axle of
the machine.
10. The brake-operating assembly as recited in claim 7, wherein the
first valve element comprises a first and a second slide valve,
each of which are arranged so that the first slide valve controls
the second slide valve when the first slide valve is activated by
the first brake pedal.
11. The brake-operating assembly as recited in claim 10, wherein
the first slide valve is connected to the shuttle valve and the
second slide valve is connected via a second brake line to the
brake cylinders, said brake cylinders being located on a second
wheel axle of the machine.
12. The brake-operating assembly as recited in claim 7, further
comprising: a pilot line for hydraulic fluid arranged between the
first and the second valve elements and adapted so that when the
second valve element is activated by the second brake pedal, the
first valve element will be activated by the hydraulic fluid in the
pilot line.
13. A brake-operating assembly for a machine, said assembly
comprising: a first brake pedal and a second brake pedal arranged
in an operator foot-space on a contractor's machine; a first valve
means for controlling flow of hydraulic fluid through a first
conduit from a pressure source to a brake cylinder of the machine
in responsive to manipulation of the first brake pedal; a second
valve means for controlling flow of hydraulic fluid through a
second conduit from the pressure source to a brake cylinder of the
machine in responsive to manipulation of the second brake pedal;
and an isolation means for permitting only one of the first and
second brake pedals to control flow of hydraulic fluid from the
pressure source to a brake cylinder of the machine at any one
time.
14. The brake-operating assembly as recited in claim 13, said
isolation means further comprising: a shuttle valve means for
precluding one of the first and second valve means from influencing
a brake cylinders when the other valve means is activated.
15. The brake-operating assembly as recited in claim 14, wherein
the first valve means further comprises a first and a second slide
valve arranged so that the first slide valve controls the second
slide valve when the first slide valve is activated by the first
brake pedal.
16. The brake-operating assembly as recited in claim 15, wherein
the first slide valve is connected to the shuttle valve and the
second slide valve is fluidly connected, via a second brake line,
to brake cylinders.
17. The brake-operating assembly as recited in claim 13, further
comprising: a pilot line for hydraulic fluid arranged between the
first and the second valve means, the pilot line being adapted so
that when the second valve element is activated by the second brake
pedal, the first valve element will be activated by the hydraulic
fluid in the pilot line.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation patent application
of U.S. application Ser. No. 09/711,668 filed 13 Nov. 2000 which is
a continuation patent application of International Application
Number PCT/SE99/00797 filed 11 May 1999 and published in English
pursuant to PCT Article 21(2), and which claims priority to Swedish
Application No. 9801672-8 filed 13 May 1998. Said applications are
expressly incorporated herein by reference in their entireties.
BACKGROUND OF INVENTION
[0002] 1. Technical Field
[0003] The present invention relates generally to a brake
arrangement and brake-operating assembly. More specifically, the
invention relates to brake arrangements for machines such a wheeled
loaders, dumpers and the like, and which arrangements are used to
brake the movement of the machine and to prevent the machine from
moving from a standstill.
[0004] 2. Background
[0005] Brake arrangements of the type generally referred to above
may take the form of a parking brake. Some machines, such as
wheeled loaders and dumpers, are provided with two brake pedals for
this function which are positioned in such a manner in a driver's
cab of the machine that the driver can use either the right foot or
the left foot to brake the machine. It is previously known to
configure such a brake arrangement in the form of a multiplate
clutch on the output transmission shaft of a wheeled loader. The
multiplate clutch functions as a parking brake and comprises a
number of plates surrounded by a fluid present in the multiplate
brake. When the parking brake is activated, the plates bear against
discs in the multiplate brake so that the plates, and thus the
output transmission shaft, are secured utilizing friction. When the
parking brake is deactivated, the plates are not in contact with
the discs in the multiplate brake, but instead rotate freely in the
surrounding fluid. It has been found, however, that the viscous
losses in such known brake arrangements are considerable when the
parking brake is deactivated and the vehicle is driven forwards.
These losses lead to increased fuel consumption by the machine. The
viscous losses occur when the plates rotate in the surrounding
fluid.
[0006] It is also previously known to provide a mechanical
connection between two brake pedals of a wheeled loader in the form
of a connecting shaft. The first brake pedal is connected to a
valve which is arranged to control the flow of hydraulic fluid from
a pressure source to brake cylinders of the machine. When the
second brake pedal is pressed down, the valve connected to the
first pedal will be acted on by virtue of the fact that the
connecting shaft between the brake pedals ensures that the first
brake pedal is also pressed down. A disadvantage of this known
brake-operated assembly is that the connecting rod occupies
otherwise usable space on the floor of the driver's cab.
[0007] In view of the above described deficiencies associated with
conventionally designed braking arrangements, the present invention
has been developed. These enhancements and benefits are described
in greater detail hereinbelow with respect to several alternative
embodiments of the present invention.
SUMMARY OF INVENTION
[0008] The present invention in its several disclosed embodiments
alleviates the drawbacks described above with respect to
conventionally designed braking arrangements and incorporates
several additional beneficial features.
[0009] One object of the present invention is to produce a brake
arrangement which is essentially loss-free when the brake
arrangement is activated. That is, such a brake arrangement results
in imperceptible losses because the locking element engages with
the output shaft only when the machine is at a standstill and there
is no contact between these components when the output shaft is
rotating. The result is that the locking element does not cause any
power losses during operation of the machine. By simultaneously
engaging the gear clutches for the respective gear steps, braking
of the vehicle can be brought about by means of the brake
arrangement. The brake arrangement can thus be used as a parking
brake which is activated when the machine is driving along or at a
standstill.
[0010] Another object of the present invention is to produce a
brake-operating assembly which eliminates a mechanical connection
between two brake pedals and thus affords a greater amount of free
floor space in the driver's cab. Among other things, this increases
the mobility of the driver and thus affords the driver greater
comfort. The brake-operating assembly according to the present
invention also affords a simpler construction and thus easier
mounting in the machine. The brake-operating assembly also leads to
greater safety because a valve element is arranged at each brake
pedal.
BRIEF DESCRIPTION OF DRAWINGS
[0011] The invention will now be described in greater detail in the
following way, by example only, and with reference to the attached
drawings, in which:
[0012] FIG. 1 is a diagrammatic, partly sectioned view of the
transmission of a machine with a brake arrangement according to the
present invention.
[0013] FIG. 2 is a diagrammatic perspective view of a locking
element according to the present invention.
[0014] FIG. 3 is a diagrammatic view of a brake-operating assembly
according to the present invention.
DETAILED DESCRIPTION
[0015] As required, detailed embodiments of the present invention
are disclosed herein. However, it is to be understood that the
disclosed embodiments are merely exemplary of the invention that
may be embodied in various and alternative forms. The figures are
not necessarily to scale, some features may be exaggerated or
minimized to show details of particular components or processes.
Therefore, specific structural and functional details disclosed
herein are not to be interpreted as limiting, but merely as a basis
for the claims and as a representative basis for teaching one
skilled in the art to variously employ the present invention.
[0016] FIG. 1 shows an exemplary embodiment of a brake arrangement
1 according to the present invention. The brake arrangement 1 is
arranged in the gearbox 2 of a machine 4, such as a wheeled loader,
dumper or similar contractor's machine. The gearbox 2 is of a known
design often characterized as a power shift type which, as in the
illustrated exemplary embodiment, comprises (includes, but is not
limited to) an input shaft 6 from an engine (not shown) and an
output shaft 8 which is connected to the drive shafts 10 of the
machine. A torque converter 12 is arranged on the input shaft 6.
Arranged in the gearbox 2 are a first, a second and a third shaft
14, 16 and 18, respectively, which each bear a number of gearwheels
20-25 that are mounted on the respective shafts 14, 16 and 18.
[0017] The output shaft 8 is connected to the third shaft 18. To
connect the gearwheels 20-25 to the shafts 14, 16 and 18, a gear
clutch 26-30 is provided for each gearwheel 20-25. The gearbox 2,
as shown, has four gear steps which are indicated by the encircled
numbers 1-4 of FIG. 1. The gearwheels 26 and 27 are intended for
forward and reverse gear, which gears are indicated by the letters
F and B in FIG. 1. To change the gear in the gearbox 2, one of the
gearwheels 20-25 is engaged by means of its associated gear clutch
26-30 at the same time as another gearwheel is disengaged by means
of its associated gear clutch. The way in which the gear changing
takes place in such a power shift gearbox is generally known by
those skilled in the art and is therefore not described in greater
detail.
[0018] The brake arrangement 1 comprises a locking element 32 which
is adapted to engage with a gearwheel 34 arranged on the output
shaft 8. FIG. 2 shows diagrammatically how such a locking element
32 can be designed. In that Figure, the locking element 32 has
assumed a locked position, a pressure spring 36 having inserted the
locking element 32 between two teeth 38 of the gearwheel 34. In
this locked position, the output shaft 8 from the gearbox 2 is
prevented from rotating which means that the machine 4 cannot move.
The locking element 32 functions as a parking brake and is intended
to engage in the gearwheel 34 when the machine 4 has stopped and is
at a standstill. The parking brake can, however, be activated while
the machine is moving. To free the locking element 32 and thus
release the parking brake, an actuator valve 40 is activated which
allows hydraulic fluid to pass to a cylinder 42 which brings the
locking element 32 out of engagement with the gearwheel 34.
[0019] A control unit 44 connected to the actuator valve 40
receives signals in a first instance from a parking brake operating
means 46, such as a push-button or a lever, and in a second
instance from a sensor 48 which measures the speed of the machine
4. The locking element 32 can be activated by the parking
brake-operating means 46 when the machine 4 is driving along. When
the machine 4 has subsequently stopped and the sensor 48 sends
signals to the control unit 44 that the speed is zero, the cylinder
42 will be emptied by the valve 40 and thereby assume the
configuration shown in FIG. 2. The pressure spring 36 then inserts
the locking element 32 between the teeth 38 of the gearwheel 34 so
that the locking element 32 bears against the flanks of the teeth
38.
[0020] In the event that the brake arrangement 1 is activated using
the parking brake-operating means 46 when the machine 4 is driving
along, as intimated to and described above, the speed of the
machine 4 must thus be braked down to zero in order for the locking
element 32 to be capable of engaging in the gearwheel 34. This
braking is brought about by the control unit 44 sending signals to
two different gear clutches 26-31 in the gearbox 2 causing the
output shaft 8 from the gearbox 2 to be braked. The gear clutches
26-31 consist of multiplate clutches; this means that the braking
of the output shaft 8 takes place proportionally to the pressure
applied to the plates. The control unit 44 is thus connected to the
gear clutches 26-31 as shown in FIG. 1. Only two gear clutches
26-31 are connected to the control unit 44 in FIG. 1, but it is of
course possible for all the gear clutches 26-31 to be connected to
the control unit 44.
[0021] If the parking brake-operating means or operator 46 is
activated when the machine 4 is driving along, the control unit 44
will thus receive information that the machine 4 is driving along.
The control unit 44 then activates two gear clutches 26-31 in the
gearbox 2, for example the gear clutches 28, 29 for first and
second gear, after which the machine 4 will be braked. The control
unit 44 subsequently receives information that the machine 4 is at
a standstill, after which the locking element 32 can be activated
by the control unit 44.
[0022] The actuator valve 40 is electrically controlled and
spring-loaded so that the actuator valve 40 takes up the position
shown in FIG. 2 when the power supply to the actuator valve 40
ceases. In this position, the cylinder 42 is drained of hydraulic
fluid to a tank 50. As the pressure spring 36 acts with a pressing
force on the locking element 32, the pressure spring 36 will guide
the locking element 32 in the direction towards the gearwheel 34
when the cylinder 42 is drained. The locking element 32 will thus
engage in the gearwheel 34 when the power supply to the actuator
valve 40 ceases. The locking element 32 is designed in such a
manner that it will bounce on the teeth 38 if the force acting
against the spring 36 disappears when the output shaft 8 is
rotating, a condition which can occur if no power is being supplied
to the actuator valve 40.
[0023] The functioning of the actuator valve 40 means that the
element 32 always engages in the output shaft 8 when the machine 4
is at a standstill and the engine is switched off, irrespective of
whether the parking brake-operating means 46 is activated or
not.
[0024] If a neutral gear position is selected, that is to say no
gear in the gearbox 2 is engaged or activated, and the parking
brake-operating means 46 is not activated, the control unit 44 will
send signals to the gear clutches 26-31 when the machine has
stopped. In this way the gearwheels 20-25 of which the gear
clutches 26-31 are applied, brake and secure the machine 4.
[0025] When the engine of the machine 4 is started, two gear
clutches 26-31 will always be activated in order to secure the
machine 4, irrespective of the position of a gear lever (not shown)
for the gearbox 2. In order to activate the gear clutches 26-31 and
also the locking element 32 and thus allow the machine 4 to be
capable of driving along, the gear lever must be shifted into a
neutral position.
[0026] In order to tow the machine 4, the locking element 32 and
the gear clutches 26-31 must be released. If the engine is switched
on, there is a bridging function in the electrical system of the
machine 4 which provides a completely disengaged transmission. In
the event of power loss or when the engine is switched off, it is
possible to release the locking element 32 mechanically by means of
an adjusting screw on the outside of the gearbox 2.
[0027] Above, a locking element 32 has been described which engages
in a gearwheel 34 arranged on the output shaft 8. However, it is
also possible to provide a locking element 32 which engages
directly with the output shaft 8, such as a dry friction multiplate
clutch or a Jaw clutch (not shown).
[0028] FIG. 3 shows a brake-operating assembly 52 for a machine 4,
such as a wheeled loader, dumper or similar contractor's machine.
The brake-operating assembly 52 comprises a first and a second
brake pedal 54 and, respectively, 56. A first valve element or
means 58 is connected to the first brake pedal 54 and a second
valve element or means 60 is connected to the second brake pedal
56. The first and second valve elements 58 and 60 are arranged so
as to control the flow of hydraulic fluid from a pressure source 62
to brake cylinders 64 and 66 which are arranged at the wheels 68 of
the machine 4 in order to brake the machine 4. Arranged between the
first and the second brake pedals 54 and 56 is a connection which
includes a connecting line 70 for conducting hydraulic fluid and
which is arranged between the first valve element 58 and the second
valve element 60.
[0029] A shuttle valve or means 72 is arranged in the connecting
line 70. The shuttle valve 72 closes the connection between the
second valve element 60 and the brake cylinders 64 when the first
valve element 58 is activated by the first brake pedal 54. When the
second valve element 60 is activated by the second brake pedal 56,
the shuttle valve 72 closes the connection between the first valve
element 58 and the brake cylinders 64.
[0030] According to the exemplary embodiment shown in FIG. 3, the
shuttle valve 72 is arranged in a first brake line 74 which is
connected to the brake cylinders 64 which are located on a first
wheel axle 76 of the machine 4. The first wheel axle 76 may be a
rear axle of the machine 4.
[0031] The first valve element 58 comprises first and second slide
valves 78, 80, respectively, which are arranged in such a manner
that the first slide valve 78 controls the second slide valve 80
when the first slide valve 78 is activated by the first brake pedal
54. As shown in FIG. 3, this control can be mechanical.
[0032] The first slide valve 78 is connected to the shuttle valve
72 and the second slide valve 80 is connected via a brake line 82
to the brake cylinders 66 which are located on a second wheel axle
84 of the machine 4. The second wheel axle 84 may be a front axle
of the machine 4.
[0033] A pilot line 86 for hydraulic fluid is arranged between the
first and the second valve element 58 and 60, so that, when the
second valve element 60 is activated by the second brake pedal 56,
the first valve element 60 will be activated by the hydraulic fluid
in the pilot line 86.
[0034] The brake pedals 54 and 56 are preferably positioned next to
one another on the floor in a driver's cab (not shown) of the
machine 4. The connecting line 70, the shuttle valve 72 and the
pilot line 86 are then positioned under the floor so that a free
space is formed on the floor between the brake pedals 54 and 56.
The brake-operating assembly 52 according to the invention is
redundant; that is to say, if one valve element 58 or 60 breaks
down, the machine 4 can still be braked by the second valve element
58 or 60. If the pressure source 62 should break down, accumulators
88 are provided, which contain hydraulic fluid under pressure. By
means of the accumulators 88, the machine 4 can be braked even in
the event that the pressure source is non-functional.
[0035] An arrangement and method of utilization for a braking
maneuvering means has been described herein. These and other
variations, which will be appreciated by those skilled in the art,
are within the intended scope of this invention as claimed below.
As previously stated, detailed embodiments of the present invention
are disclosed herein; however, it is to be understood that the
disclosed embodiments are merely exemplary of the invention that
may be embodied in various forms.
* * * * *