U.S. patent number 3,905,501 [Application Number 05/438,378] was granted by the patent office on 1975-09-16 for control means for public works machine.
This patent grant is currently assigned to Societe Anonyme: Poclain. Invention is credited to Jean E. Leroux.
United States Patent |
3,905,501 |
Leroux |
September 16, 1975 |
Control means for public works machine
Abstract
An earthworking machine having separate hydraulic drive motors
for front and rear wheels and a hydraulic cylinder for lifting or
lowering a forwarding extending work bucket is disclosed with work
fluid for the cylinder being provided solely through a
three-position regulator valve having both a manually operable
positioning member and an automatically operable positioning means
responsive to differences in hydraulic feed pressure to the drive
motors for effecting a raising or lowering of the work bucket to
maintain the front and rear wheels in ground contact; in a first
embodiment the control valve is directly actuated by hydraulic feed
fluid from the inputs to the vehicle drive motors and in a second
embodiment, pilot fluid is provided through a regulator operated by
the feed motor fluid to the three-position regulator valve.
Inventors: |
Leroux; Jean E. (Le
Plessis-Belleville, FR) |
Assignee: |
Societe Anonyme: Poclain (Le
Plessis-Belleville, FR)
|
Family
ID: |
9114639 |
Appl.
No.: |
05/438,378 |
Filed: |
January 31, 1974 |
Foreign Application Priority Data
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|
|
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Feb 9, 1973 [FR] |
|
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73.04754 |
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Current U.S.
Class: |
414/699;
414/708 |
Current CPC
Class: |
E02F
3/434 (20130101); E02F 9/2239 (20130101); E02F
9/2292 (20130101) |
Current International
Class: |
E02F
9/22 (20060101); E02F 3/43 (20060101); E02F
3/42 (20060101); E02F 003/85 () |
Field of
Search: |
;214/138,140,762,771,778 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Werner; Frank E.
Assistant Examiner: Weaver; Ross
Attorney, Agent or Firm: Mason, Fenwick & Lawrence
Claims
I claim:
1. A public works machine comprising:
a frame,
a set of front driving wheels to which at least one first hydraulic
driving motor is coupled;
a set of rear driving wheels to which at least one rear hydraulic
driving motor is coupled;
means for supplying fluid under pressure to said front and rear
motors and connected thereto by respective feed pipes;
a discharge reservoir means;
working equipment articulated to said frame;
a double-acting drive member coupled between said frame and said
working equipment and which comprises two chambers;
a first pipe and a second pipe connected respectively to said two
chambers;
a three-position regulator comprising the sole valve means for
providing work fluid for said double-acting drive member which:
in a first position connects said first pipe to said fluid supply
means and said second pipe to said discharge reservoir means;
in a second position connects said first pipe to said discharge
reservoir means and said second pipe to said fluid supply
means;
and, in a third position blocks said first and second pipes;
manually operable means for selecting the position of said
regulator;
and, automatically operable control means for automatically
positioning said regulator in accordance with the values of the
torques opposing said front and rear sets of wheels and comprising
a double-acting drive device having two chambers which are
respectively connected to a third pipe and a fourth pipe which can
be placed in communication respectively with fluids at pressure
corresponding to those in said feed pipe to said front and rear
motors, and a return member tending to maintain said regulator in
its third position when the effects of the pressure of fluids in
said two chambers are equal and opposite.
2. A machine as claimed in claim 1, additionally including a
two-position regulator, in the first position of which corresponds
to effective operation of said automatically operable control means
in which communication is established between said two chambers of
said drive device and fluids at pressures corresponding to those in
said feed pipes to said front and rear motors, and in the second
position of which said automatically operable control means is
taken out of operation and said two chambers of the drive device
are placed in communication with said discharge reservoir
means.
3. A machine as claimed in claim 2, wherein said feed pipes to said
front and rear motors are connectable by said third and fourth
pipes to respective one of said chambers of said drive device and
said two-position regulator is interposed between said third and
fourth pipes and said feed pipes to the front and rear motors, in
its first position said regulator placing said third and fourth
pipes in communication with said feed pipes, and in its second
position said regulator placing said third and fourth pipes in
communication with said discharge reservoir means.
4. A machine as claimed in claim 2, wherein said automatically
operable control means includes a second three position regulator
to which is coupled a second automatically operable means for
selection of the position of the second three-position regulator in
dependance on the values of the torques opposing the front and rear
wheels and which comprises a double-acting drive device having two
chambers and a return member tending to maintain said second
regulator in its third position, when the effects of the pressures
of fluids in said two chambers are equal and opposite said two
chambers of said second automatically operable device being
connected respectively by pipes to said feed pipes to said front
and rear motors, and wherein said third and fourth pipes are
connected to said second three-position regulator, a fifth pipe
connected to means for supplying fluid under pressure and a sixth
pipe connected to a discharge reservoir are connected to said
second three-position regulator, the three positions of said second
three-position regulator correspond to the preponderance of the
effect of fluid in one or other of said chambers of said second
automatically operable means, or with equality of the said effects,
and said second three-position regulator connects said third pipe
to said fifth pipe and said fourth pipe to said sixth pipe in its
first position, said third pipe to said sixth pipe and said fourth
pipe to said fifth pipe, in its second position and said third and
fourth pipes to said sixth pipe in its third position and wherein
said two-position regulator is arranged in said fifth pipe which it
separates into two portions and is connected by a seventh pipe to
said discharge reservoir means, in its first position said
two-position regulator places said two portions of said fifth pipe
to which it is connected in communication in its second position
said two-position isolates said two portions of the fifth pipe from
one another and places said seventh pipe in communication with that
one of said two portions of said fifth pipe which is connected to
said second three-position regulator.
5. A machine as claimed in claim 1, wherein said feed pipes to said
front and rear motors are respectively connectable by said third
and fourth pipes to respective ones of said chambers of said drive
device.
6. A machine as claimed in claim 1, wherein said automatically
operable control means includes a second three-position regulator
to which is coupled a second automatically operable means for
selection of the position of the second three-position regulator in
dependance on the values of the torques opposing the front and rear
wheels and which comprises a double-acting drive device having two
chambers and a return member tending to maintain said second
regulator in its third position, when the effects of the pressures
of fluids in said two chambers are equal and opposite said two
chambers of said second automatically operable device being
connected respectively by pipes to said feed pipes to said front
and rear motors, and wherein said third and fourth pipes are
connected to said second three-position regulator, a fifth pipe is
connected to means for supplying fluid under pressure and a sixth
pipe connected to a discharge reservoir are connected to said
second three-position regulator, the three positions of said second
three-position regulator correspond to the preponderance of the
effect of fluid in one or other of said chambers of said second
automatically operable means, or with equality of the said effects,
and said second three-position regulator connects said third pipe
to said fifth pipe and said fourth pipe to said sixth pipe in its
first position, said third pipe to said sixth pipe and said fourth
pipe to said fifth pipe, in its second position and said third and
fourth pipes to said sixth pipe in its third position.
Description
The present invention is concerned with improvements in and
relating to public work machines and in particular with
improvements in machines adapted to use the method described in
U.S. Pat. No. 3,782,572.
According to the present invention there is provided a public works
machine comprising:
A frame,
A set of front driving wheels to which at least one first hydraulic
driving motor is coupled;
A set of rear driving wheels to which at least one rear hydraulic
driving motor is coupled;
Means for supplying fluid under pressure to said front and rear
motors and connected thereto by respective feed pipes;
Discharge reservoir means;
Working equipment articulated to said frame;
A double-acting drive member coupled between said frame and said
working equipment and which comprises two chambers;
A first pipe and a second pipe connected respectively to said two
chambers;
A three-position regulator which:
In a first position connects said first pipe to said fluid supply
means and said second pipe to said discharge reservoir means;
In a second position connects said first pipe to said discharge
reservoir means and said second pipe to said fluid supply
means;
And, in a third position blocks said first and second pipes;
Manually operable means for selecting the position of said
regulator;
And, automatically operable means for selecting the position of
said regulator in dependance on the values of the torques opposing
said front and rear sets of wheels and comprising a double-acting
drive device having two chambers which are connected respectively
to a third pipe and a forth pipe which can be placed in
communication respectively with fluids at pressures corresponding
to those in said feed pipes to said front and rear motors, and a
return member tending to maintain said regulator in its third
position when the effects of the pressures of fluids in said two
chambers are equal and opposite.
In one embodiment the machine also comprises a two-position
regulator, in the first position of which corresponds to effective
operation of said automatically operable means, communication can
be established between said two chambers of said drive device and
fluids at pressures corresponding to those in said feed pipes to
said front and rear motors, and in the second position of which,
which corresponds to the placing of said automatically operable
means out of operation, said two chambers of the drive device are
placed in communication with said discharge reservoir means.
The feed pipes to said front and rear motors may be connected
respectively by said third and fourth pipes to said two chambers of
said drive device.
In this case said two-position regulator is preferably interposed
between said third and fourth pipes and said feed pipes. In its
first position it places said third and fourth pipes in
communication with said feed pipes, and in its second position it
places said third and fourth pipes in communication with said
discharge reservoir means.
In a second embodiment the machine comprises a second
three-position regulator to which is coupled a second automatically
operable means for selection of the position of the second
three-position regulator in dependance on the values of the torques
opposing the front and rear wheels and which comprises a
double-acting drive device having two chambers and a return member
tending to maintain said second regulator in its third position,
when the effects of the pressure of fluids in said two chambers are
equal and opposite said two chambers of said second automatically
operable device being connected respectively by pipes to said feed
pipes to said front and rear motors, and wherein said third and
fourth pipes are connected to said second three-position regulator,
a fifth pipe connected to means for supplying fluid under pressure
and a sixth pipe connected to a discharge reservoir are connected
to said second three-position regulator, the three positions of
said second three-position regulator correspond to the
preponderance of the effect of fluid in one or other of said
chambers of said second automatically operable means, or with
equality of the said effects, and said second three-position
regulator connects said third pipe to said fifth pipe and said
fourth pipe to said sixth pipe in its first position, said third
pipe to said sixth pipe and said fourth pipe to said fifth pipe in
its second position and said third and fourth pipes to said sixth
pipe in its third position.
Advantageously in this machine said two-position regulator is
arranged in said fifth pipe which it separates into two portions
and is connected by a seventh pipe to said discharge reservoir
means, in its first position said two-position regulator places
said two portions of said fifth pipe to which it is connected in
communication in its second position said two-position regulator
isolates said two portions of the fifth pipe from one another and
places said seventh pipe in communication with that one of said two
portions of said fifth pipe which is connected to said second
three-position regulator.
The invention will be better understood from the following
description of an embodiment thereof, given below by way of example
only, with reference to the accompanying drawings, in which:
FIGS. 1 and 2 illustrates diagrammatically a machine of the loader
type during two phases of use;
FIG. 3 shows the hydraulic circuit of an embodiment of a machine in
accordance with the invention; and
FIG. 4 shows the hydraulic circuit of another embodiment of a
machine in accordance with the invention.
A public works machine, such as a loader, may in a first phase of
use tend to adopt the position shown in FIG. 1. As the machine
moves forward, the bucket 1 bears on material 2 but does not
succeed in penetrating into the material. The force of the reaction
of the material 2 against the bucket 1 is transmitted by the
working equipment 3 to the frame 4 of the machine with the result
that the front wheels 5 of the machine tend to lose contact with
the ground 6.
In another phase of use illustrated in FIG. 2 when, for example,
the bucket 1 tries to lift all or a portion of the material 2 the
rear wheels 7 of the machine tend to lift from the ground 6.
As shown in FIGS. 1 and 2, a double-acting jack 8 is coupled
between the working equipment 3, which is articulated on the frame
4 for pivotal movement about the axis 9, and the said frame 4. To
this end the piston-rod of the jack is articulated on the working
equipment 3 for pivotal movement about the axis 10 and the cylinder
is articulated on the frame 4 for pivotal movement about axis
11.
In one embodiment of the invention shown in FIG. 3 the two chambers
12 and 13 of the jack are connected to a first three-position
regulator 14 respectively by a first pipe 15 and a second pipe 16.
The regulator 14 is in turn connected by pipes 17 and 18 to a
hydraulic pump 19 and a discharge reservior 20 respectively. The
movable member of the regulator 14 has three positions as
follows:
in the first position the pipe 15 is placed in communication with
the pipe 17 and the pipe 16 with the pipe 18,
in the second position, the pipe 15 is placed in communication with
the pipe 18 and the pipe 16 with the pipe 17, and
in the third position the pipe 17 is placed in communication with
the pipe 18 and the pipes 15 and 16 are blocked at the
regulator.
Also shown in FIG. 3 are the hydraulic driving motor or motors 21
for the front wheels and the hydraulic driving motor or motors 22
for the rear wheels. Each of these motors comprises two chambers
capable selectively of being put in communication with a pump 23,
24 respectively and with the discharge reservoir 20 by means of
manually operatable regulators 25, 26 which may, if required, be
coupled. These regulators each have three positions. They are
connected to the two chambers of the respective motor by two pipes,
the regulator 25 by the pipes 27 and 28 to the motor 21, the
regulator 26 by the pipes 29 and 30 to the motor 22, and to the
pumps 23, 24 and the reservoir 20, the regulator 25 by the pipes 31
and 32, the regulator 26 by the pipes 33 and 34. In the first
position of each regulator 25, 26 the pipes 27 and 31, 28 and 32,
29 and 33, 30 and 34 are placed in communication. In the second
positions of these regulators the pipes 27 and 32, 28 and 31, 29
and 34, 30 and 33 are placed in communication. Finally, in the
third positions of the regulators 25 and 26 the pipes 31 and 32 and
33 and 34 are placed in communication and the pipes 27, 28, 29 and
30 are blocked at the regulators.
It will be observed that the regulator 14 is provided with a lever
35 for optional manual, as shown, or pedal control of the positiin
of its movable member. In addition the regulator 14 is coupled to a
resilient member 36 which acts to bias the movable member of the
regulator 14 to its third position, and to a double-acting jack
indicated diagrammatically by the chambers 37 and 38, the action of
fluid under pressure capable of being contained in the chambers 37,
38 being opposite that of the resilient member 36.
A two-position regulator 39 is connected by pipes 40 and 41 to the
chambers 37 and 38 respectively, and by pipes 42 and 43 to the
delivery pipes 31 and 33 respectively, from the pumps 23 and 24. A
pipe 44 connects the regulator 39 to the reservoir 20.
The regulator 39 has a manual control 45. The two positions of its
movable member are as follows:
in the first position, the pipes 41 and 42, 40 and 43 are placed in
communication and the pipe 44 is blocked at this regulator;
in the second position, the three pipes 40, 41 and 44 are placed in
communication and the pipes 42 and 43 are blocked at this
regulator.
It is to be observed that pipes 46 connect the delivery pipes 17,
31, 33 of the various pumps to the reservoir 20 by means of pipes
18, 32 and 34, respectively, a calibrated discharge valve 47 being
arranged in each of the pipes 46.
In the embodiment of FIG. 4 a number of the members already
described with reference to FIGS. 1 to 3 are again found. Similar
members are indicated by the reference numbers used in FIGS. 1 to
3.
In this embodiment the pipe 18 consists of two sections 18a and 18b
which are connected to the distributor 14, a non-return valve 48
being arranged in the section 18a of the said pipe 18, which is
tapped off from the delivery pipe 17 from the pump 19. The section
18b is connected to the reservoir 20. The non-return valve 48
enables flow of the fluid from the pump 19 towards the regulator 14
through the pipe 18a.
The three positions of the regulator 14 are therefore as
follows;
in the first position, the pipes 15 and 17 and the pipes 16 and 18b
are placed in communication the pipe 18a is blocked at the
regulator 14;
in the second position, the pipes 15 and 18b and the pipes 16 and
17, are placed in communication and the pipe 18a is again blocked
at the regulator 14; and
in the third position, the pipes 18a and 18b are placed in
communication, and the pipes 15, 16 and 17 are blocked at the
regulator
Another three-position regulator 49 is coupled to a resilient
member 50 which acts to bias the movable member of the regulator 49
into one of its positions, called the third position or mean
position, and to a double-acting jack indicated diagrammatically by
the chambers 51 and 52, the action of fluid under pressure capable
of being contained in the chambers 51, 52 being opposite to that of
the resilient member 50. The chambers 51 and 52 are connected by
pipes 53 and 54 to the delivery pipes 31 and 33 from the pumps 23
and 24 respectively. In addition a pipe 62 connects the regulator
49 to the reservoir 20.
A two-position regulator 55 is connected to the delivery pipe 56
from a low-pressure pump 57, and to the reservoir 20 by a pipe 58.
Finally, a pipe 59 connects the regulators 49 and 55. The pump 57
is connected to the reservoir 20 by its suction pipe 60, and a pipe
46 is tapped off from the delivery pipe 56 and is connected to the
reservoir 20, a calibrated discharge valve 47 being arranged in the
pipe 46. The regulator 55 is provided with a manual controller 61
for controlling the position of its movable member.
The three positions of the regulator 49 are as follows:
in the first position, the pipes 40 and 59 and 41 and 62 are placed
in communication;
in the second position, the pipes 40 and 62 and 41 and 59 are
placed in communication; and
in the third position, the three pipes 40, 41 and 62 are placed in
communication, and the pipe 59 is blocked at the regulator 49.
The two positions of the regulator 55 are as follows:
in the first position, the pipes 56 and 59 are placed in
communication and the pipe 58 is blocked at the regulator 55,
and
in the second position, the pipes 58 and 59 are placed in
communication and the pipe 56 is blocked at the regulator 55.
The pumps 19, 23 and 24 are again connected to the reservoir 20 by
suction pipes 63.
From the following explanation of the operation of the above
described machines, the advantages that such machines offer, and
the progress that they represent with respect to known machines,
will become apparent. In order to simplify the explanation, only
the operation of the machine while running forwards will be
considered.
Firstly the operation of the circuit described with reference to
FIG. 3 will be examined. It is assumed that the regulator 39 is
initially in its first position. When the machine tends to adopt
the position of FIG. 1 and when therefore the bearing load of the
front wheels on the ground 6 is reduced, the relative torque
opposing the wheels 5 is likewise reduced. A drop in pressure is
observed in the fluid in the feed pipe 27 to the motors 21 of the
front wheels 5 as well as in the delivery pipe 31 from the pump 23
connected to the pipe 27. The pressure in the pipes 42 and 41,
which are connected to the pipe 31, is likewise low. If there is
still good adhesion between the rear wheels 7 and the ground the
pressures in the pipes 27, 31 and 29, 33, or 41 and 40 are
significantly different, so that, as a function of the sections of
the chambers 37 and 38 and of the stiffness of the spring 36, the
movable member of the regulator 14 is pushed into its second
position.
The pump 19 through the pipes 17 and 16 feeds the chamber 13 of the
jack 8 with fluid under pressure. The rod of the jack 8 is thus,
biased outwardly, which brings about a lifting of the working
equipment 3 and consequently a return of the front wheels 5 towards
the ground 6. When the wheels 5 have regained contact, the relative
torque opposing those wheels increases again and the pressure in
the pipes 27, 31 and 42 and 41 likewise increases. The movable
member of the regulator 14 is then biased towards its intermediate
position (third position) under the effect of the return member 36.
There has thus been achieved automatically and in a subordinate
manner balancing of the tractive forces which act upon the two sets
of front wheels 5 and rear wheels 7.
Of course it is easily understood that a similar operation is
obtained in the case in which the rear wheels 7 tend to move out of
contact with the ground 6. It is not considered necessary to
describe in detail the manner of operation, which is very similar
to that which has just been described of the machine in this other
configuration.
It may be found desired to neutralise temporarily the above
described subordination, for example in the case when, in order to
change a front wheel, it is desired effectively to raise this wheel
5 clear of the ground 6 and keep it clear. In order to do this it
is sufficient to place the regulator 39 in its second position by
action on the lever 45. In that manner the chambers 37 and 38 are
put in communication with the reservoir 20 through the pipes 40, 41
and 44. The resilient member 36 alone acts on the movable member of
the regulator 14 and returns the movable member permanently into
its third position. The pump 19 delivers fluid to the reservoir 20
through the pipes 17 and 18 and, because the pipes 15 and 16 are
blocked at the distributor 14, the chambers 12 and 13 of the jack 8
are isolated and the rod of the said jack 8 is maintained in
position with respect to the cylinder of this jack.
The functioning of the machine which has been described thus is an
automatic control of the opposing torques acting concomitantly on
the wheels of the two sets of front 6 and rear wheels 4, and an
automatic subordinate adjustment of the position of the working
equipment 3 to the values of these opposing torques. In this way
the best possible adhesion of the driving wheels 5 and 7 is
obtained and consequently, at given power from the machine, the
maximum force of penetration for the tool 1, without its being
necessary for the driver of the machine to have to appreciate the
adhesion conditions at the time, or to be particularly experienced
in reacting in optimum manner.
Furthermore the circuit of FIG. 3 is considerably simpler than that
described in the above referred to U.S. Pat. No. 3,782,572 in the
sense that the regulator 14 and the pump 19 are used both to supply
fluid under pressure to one of the chambers 12 or 13 and place the
other chamber in communication with the reservoir 20 by operation
on the lever 35, and to subordinate the position of the working
equipment 3 to the values of the torques opposing the wheels 5 and
7 by the action of fluid in the chambers 37 and 38 and of the
resilient member 36.
In certain cases, it may, however, be desired to "pilot" the
movable member of the regulator 14 by a low-pressure fluid. This
requirement is present particularly when it is desired to obtain
simple manufacture of the regulator 14. In this case the circuit of
FIG. 3 is slightly modified to interpose an intermediate state of
pilotage. Thus one arrives at the arrangement described with
reference to FIG. 4.
In FIG. 4 the regulator 55 is similar to the regulator 39 of FIG.
3.
It is assumed first of all that the distributor 55 is in its first
position. The pressures of the fluids in the feed pipes 27 and 29
to the motors 21 and 22, and consequently in the pipes 31 and 53
and 33 and 54 act to place the movable member of the regulator 49
in one of its positions. For example, when the front wheels 5 have
a tendency to lift, the pressure falls in the pipes 27, 31 and 53
so that the regulator 49 is placed in its first position. Fluid
delivered to the pipe 56 by the low-pressure pump 57 flows through
the pipes 59 and 40 to the chamber 37 while the chamber 38 is
placed in communication with the reservoir 20 through the pipes 41
and 62. Thus the regulator 14 is placed in its second position. In
this position the fluid delivered by the pump 19 flows to the
chamber 13 through the pipes 17 and 16, and fluid contained in the
chamber 12 is delivered to the reservoir 20 through the pipes 15
and 18b. As in the previously described embodiment of FIG. 3, the
rod of the jack 8 is biased outwardly of the cylinder of this jack
and the working equipment 3 is raised to bring the front wheels 5
back into contact with the ground 6.
Operation of the circuit of FIG. 4 is exactly similar when the rear
wheels 7 are raised from the ground. Thus both automatic
subordination and subordination by pilotage of the main regulator
14 of the device as FIG. 3 is obtained. However, the regulator 14
is now piloted by the low-pressure fluid delivered by the pump 57
and not directly by the high-pressure fluid in the feed pipes 27
and 29 to the motors 21 and 22. Manufacture of the regulator 14 is,
as a result, considerably easier.
When the regulator 55 is placed in its second position flow of the
"pilotage" fluid, delivered to the pipe 56 by the pump 57, is cut
off from the regulator 14 and from the chambers 37 and 38.
Consequently the chambers are no longer fed with fluid under
pressure (under low pressure, moreover) so that the effect of the
resilient member 36 becomes preponderant and returns the regulator
14 to its third position. The pipes 15 and 16 are then blocked at
the regulator 14 and, because the chambers 12 and 13 of the jack 8
are isolated, the rod of the jack 8 is maintained in position with
respect to the cylinder of this jack. Subordination in position is
neutralised.
It will be understood that the characteristics of the operation are
maintained when the regulators 25 and 26 are arranged not as
previously described to make the motors 21 and 22 rotate in the
direction for running forwards, but are arranged to make the motors
21 and 22 rotate in the direction for running backwards.
It will be observed that in the various cases in which the pressure
of fluid acts either in the chamber 37 or in the chamber 38 the
effect of this pressure is sufficiently large to oblige the driver
to follow the displacement of the manual control lever 35, so that
the operation providing subordination prevails.
* * * * *