WO2012031325A1

WO2012031325A1 - Pneumatic control

Info

Publication number: WO2012031325A1
Application number: PCT/AU2011/001157
Authority: WO
Inventors: Mani Balasubramanian; Roland Fernando Cabrera
Original assignee: David Brown Engineering & Hydraulics Pty Ltd
Priority date: 2010-09-09
Filing date: 2011-09-09
Publication date: 2012-03-15

Abstract

A pneumatic control for activation and control of hydraulic and/or pneumatic equipment; said control combining activation and control of at least a first hydraulic device by rotation of a first control element and control of a second hydraulic or pneumatic device by linear displacement of a second control element relative said first control element.

Description

PNEUMATIC CONTROL

The present invention relates to pneumatic control of devices and, more particularly, to pneumatic control of vehicle mounted hydraulic and/or pneumatic devices.

BACKGROUND

At least some vehicle mounted hydraulic and pneumatic devices are preferably controlled from within the cabin of the vehicle. To obviate the need for hydraulic lines and pipework within the cabin it ia common to use an air over hydraulic arrangement in which compressed air controlled from within the cabin, is used to activate the valve block/s of the hydraulic device/s mounted at some convenient location near or at each device. Typical of auch devices are the usually pneumatically activated power take-off (PTO) mounted at the vehicle gear box and an hydraulic ram such as used for a tipping tray for example .

A disadvantage with known pneumatic control modules is that they are frequently bulky and difficult to mount. Typically also use is by means of projecting levers which may be injurious in case of accident or, if not properly gated, may be inadvertently activated with possibly serious consequences if the status of an hydraulic device is unexpectedly altered.

There is thus a need for a compact, easily mounted and inherently safe pneumatic control module for in-cabin operation of vehicle mounted hydraulic devices. It is an object of the present invention to address or at least ameliorate some of the above disadvantages.

Notes

1, The term "comprising" (and grammatical variations thereof) is used in this specification in the inclusive sense of "having" or "including", and not in the exclusive sense of "consisting only of".

2. The above discussion of the prior art in the Background of the invention, is not an admission that any information discussed therein is citable prior art or part of the common general knowledge of persons skilled in the art in any country.

BRIEF DESCRIPTION OF INVENTION

Accordingly,, in a first broad form of the invention, there is provide a pneumatic control for activation and control of hydraulic and/or pneumatic equipment/ said control combining activation and control of at least a first hydraulic device by rotation of a first control element and control of a second hydraulic or pneumatic device by linear displacement of a second control element relative said first control element. Preferably, said first and second control elements are combined in a single control module; said control module adapted for mounting in a vehicle control cabin.

Preferably, said first control element comprises a rotatable, generally cylindrical control knob projecting from said control module; said second control element comprising a pushbutton assembly located within a central aperture of said first control element.

Preferably, said first control element includes an internal annular skirt generally depending from said central aperture; said annular skirt having an uneven lower annular portion so as to form a cam.

Preferably, said pushbutton assembly of said second control element is retained in an activated depressed position after a first pressing of said pushbutton assembly; said pushbutton assembly returning to a deactivated position when applying a second pressing while in said depressed position.

Preferably, said pushbutton assembly comprises an outer member and an inner member; said outer member connected to said inner member by an axially sliding connection; said inner member provided with radially projecting fins; said fins slidingly located in grooves provided in an internal surface of said annular skirt, when said pushbutton is in said deactivated position. Preferably, cooperating portions of said outer and inner members are arranged such that a first linear depressing of said outer member induces sufficient linear displacement and rotation of said inner member to disengage said fins from said grooves; 9aid fins rotated to an intermediate position at which said fins engage a recessed rim portion of said skirt.

Preferably, a second depressing further rotates said inner member to re-align said fins with said grooves/ said fins re-entering said grooves, thereby returning said pushbutton assembly to said deactivated state through urging of a spring element.

Preferably, said control module further includes an integrally formed valve block; said valve block including three cylindrical valve chambers; a first cylindrical valve chamber arranged coaxial with said central aperture, a second and third cylindrical valve chamber arranged on either side of said first valve chamber; the arrangement being such that the axes of said second and third valve chambers intersect diametrically opposite points on a lower annular portion of said annular skirt.

Preferably, each said valve chamber is provided with a spring-loaded plunger assembly; a first spring-loaded plunger assembly of said first valve chamber urged against said inner member of said pushbutton assembly; second and third spring-loaded plunger assemblies of said second and third valve chambers urged against said diametrically opposite points on said lower annular portion of said annular skirt.

Preferably, the form of said cam of said lower annular portion is arranged with a section projecting below a general plane of the remaining section of said annular portion; said projecting section having an area of maximum projection with sloping shoulder areas extending in each circumferential direction away from said area of maximum projection.

Preferably, said first control element is arranged to rotate between clockwise and anticlockwise limits; said first control element being in a non activating state when rotated to a mid point between said limits; said maximum area of projection of said cam then positioned between said points of contact of said second and third spring-loaded plungers with said lower edge of said annular skirt.

Preferably, a clockwise or anticlockwise rotation of said first control element drives a respective one of said sloping shoulder areas against either said second or said third spring-loaded plunger; said rotation depressing a respective said spring-loaded plunger to open a valve at a lower end of respective said second ox third valve chamber; said valve opened to a maximum when said area of maximum projection is coincident with said spring-loaded plunger. Preferably, respective said sloping shoulder areas are asymmetric/ shape of said sloping shoulder areas determining differential degrees of rates of opening of respective said air passages, according to the degree of clockwise or anticlockwise rotation of said first control element .

Preferably, depressing said second control element into said activated state urges said first spring-loaded plunger assembly to open a valve at a lower end of said first valve chamber.

Preferably, each said first, second and third cylindrical valve chamber is connected to a common air supply manifold integrally formed with said valve block; said manifold adapted for connection to a compressed air supply,

Preferably, each cylindrical valve chamber communicates with an air outlet spigot; each said spigot adapted for connection to an air line for communication with a said hydraulic and/or pneumatic device.

Preferably, first and second ones of said outlet spigots are connected by air lines to an hydraulic valve block controlling an hydraulic ram; said first control element providing progressive speed control of operation of said ram in extension and retraction.

Preferably, a first of said outlet spigots is connected by an air line to pneumatic actuator controlling a power take-off unit of said vehicle; depressing of said second control element pushbutton assembly causing said pneumatic actuator to engage said power take-off.

Preferably, said module is adapted for mounting in the control cabin of a vehicle.

In another broad form of the invention, there is provided a method of pneumatic control of hydraulic and/or pneumatic devices of a vehicle; a said hydraulic device requiring gradated control of rate of operation; a said pneumatic device requiring switching between an activated and a non- activated state; said method including the steps of;

(a) combining a first and second control element in a pneumatic control module,

(b) providing said first control element as a rotating element, said rotating element including a cam arranged for gradual opening of either a second or third pneumatic valve,

(c) providing said second control element as a pushbutton assembly; a first pressing of said pushbutton assembly causing linear displacement and opening a first pneumatic valve; said valve remaining open until application of a second pressing of said pushbutton, and

wherein said pushbutton assembly of said second control element is located in a central aperture of said first control element. BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the present invention will now be described with reference to the accompanying drawings wherein:

Figure 1 is a perspective view of a preferred embodiment of a pneumatic control module according to the invention,

Figure 2 is a perspective view of a first and second control element and a valve block of the module of Figure 1,

Figure 3 is a plan view of the first and second control elements of the pneumatic control module of Figure 1,

Figure 4 is an enlarged sectioned view of the first and second control elements and valve block of Figure 2 and in which both first and second control elements are in a non-activated state_/

Figure 5 is an enlarged sectioned view of the first and second control elements according to the invention,

Figure 6 is a perspective view of a further preferred configuration of a pneumatic control module according to the invention, DETAILED DESCRIPTION. OF PREFERRED EMBODIMENTS

With reference to Figure 1, the pneumatic control module 10 of the present invention comprises a housing 12 from which project a first control element 14 and, recessed into a central aperture of the first control element, a second control element 1G. The housing 12 may conveniently accommodate a proprietary third control element 18, for example a combined pneumatic/electric control switch as shown in Figure 1, but the present invention resides in the first and second control elements 14 and 16 and their associated mechanisms and valving.

First control element 14 comprises a generally cylindrical knob 20 which may be rotated clockwise and anticlockwise, as best seen in Figures 2 and 3, between limits (not shown) . A spring 22 (visible in Figure 4) is biased to return knob 20 to its default, centralised position (labelled "HOLD" in the example shown in Figure 3) . The central aperture of cylindrical knob 20 houses the second control element 16 in the form of a pushbutton.

Turning now also to Figures 4 and 5, it can be seen that the first control element knob 20 includes an internal, stepped annular skirt 24 depending from the central aperture. This forms a well 26 in which the pushbutton may be linearly displaced from its non-activated state (as shown in Figures 1 to 5) relative to the first control element knob 20.

A lower annular portion 28 of annular skirt 24, is uneven, with a section of the lower edge projecting below the general plane of the remaining section of the annular portion 28 to form a cam 30. The area of maximum projection 32 (highest point of the cam) is flanked by sloping shoulders 34 and 36 extending circumferentially away in both the clockwise and anticlockwise directions from the area of maximum projection 32.

The pushbutton of second control element 16 is an assembly of two components; an outer member 38 and an inner member 40, the outer member 38 being connected to the inner member 40 by an axially eliding connection 42. The inner member 40 ie provided with radially projecting fins 44. These slidlngly locate in grooves 46 provided in the internal surface of the stepped annular skirt 24, when the pushbutton is in the deactivated position shown in Figures 1 to 5.

Outer member 38 is provided with a toothed lower edge 46, while the radially projecting fins 44 of the inner member 40 have chamfered upper ends 50. These cooperating portions are so arranged such that a first linear depressing of the outer member

Induces linear displacement and rotation of the inner member. The displacement is sufficient to slide the fins 44 out of the grooves 46, with the rotation causing the fins to rotate into an intermediate position at which the fins engage with, and are retained at a recessed rim portion 52 of the skirt 24.

A second depressing of the outer member 38 further rotates the inner member 40 to re-align the fins 44 with the grooves 46. Urged by a spring 54 (see Figure 4) the fins re-enter the grooves, returning the pushbutton assembly to the deactivated state shown in Figures 1 to 5.

Referring now to Figures 2 and 4, pneumatic control module 10 further includes an integrally formed valve block 60. Valve block 60 includes three cylindrical valve chambers 62, 64 and 66. The first valve chamber 62 is arranged coaxial with the central aperture of knob 20 and the pushbutton assembly 38, 40. The second and third cylindrical valve chambers 64 and 66 are arranged on either side of the first valve chamber 62 . The arrangement is such that the axes of the second and third valve chambers Intersect diametrically opposite points 68 and 70 on the annular lower portion 28 of the stepped skirt 24 of the first control element knob 20 .

A common manifold 72 and air inlet spigot 74, integral with the valve block 60 , provide compressed air from a compressor to the lower ends of each of the three valve chambers. Each of the valve chambers 62 , 64 and 66 is provided with a spring-loaded plunger assembly, 76, 78 and 80 respectively. Depressing of the plunger in a valve chamber opens the valve, 82 , 84 or 86 respectively of that chamber, allowing air to pass to an outlet spigot, 88 , 90 or 92 for that chamber.

The first spring-loaded plunger assembly 76 of the first valve chamber 62 , is urged against the inner member 40 of the pushbutton assembly, while the second and third spring-loaded plungers 64 and 66, of the second and third valve chambers are urged against the diametrically opposite points 68 and 70 on the annular lower portion 28 of the annular skirt 24. In a preferred arrangement, the plunger assembly 80 of the third valve chamber 66 is provided with an intermediate relief spring 81 to regulate air pressure in chamber 66, Each plunger assembly is further provided with central vent passages to vent the chambers after activation and return of the valves 82 , 84 and 86 to their closed positions. When the knob 20 of the first control element 14 is at the mid point between the limits of its possible rotation (that is in the default "HOLD" position shown in Figure 1 to 5), it is in a non-activating state. The area of maximum projection 32 of the cam 30 is then positioned between the points of contact 68 and 70 of the second and third spring-loaded plungers 78 and 80 with the annular lower portion 28 of the annular skirt 24.

It will be understood that a clockwise or anticlockwise rotation of the first control element knob 20 drives a respective sloping shoulder 34 or 36 of the cam 30 against either the second or third spring-loaded plunger assembly 80 or 78. Thus the rotation depresses the respective spring-loaded plunger assembly, at a rate determined by the speed of rotation of knob 20 and the shape of cam 30 to rapidly or progressively open an air passage at a lower end of the respective second or third valve chamber 66 or 64. The valves are opened to a maximum when the area of maximum projection 32 of the cam 30 is coincident with a spring-loaded plunger,

In a preferred arrangement, the respective sloping shoulders 34 and 36 of the cam 30 may be asymmetric, as clearly shown in Figure 5, with the shape of the sloping shoulders determining differential degrees of the rate of opening of the respective valves 86 and 84 according to the degree of clockwise or anticlockwise rotation of the first control element knob 20.

In the example of a cam shape shown in Figures 4 and 5, turning knob 20 anticlockwise almost instantly opens valve 84, while clockwise rotation gradually opens valve 86. By this means, the spool of an hydraulic control valve can be driven in a first direction by the application of air pressure to the first air pilot of the control valve. For example for an hydraulic ram of tipping truck body, the body may be lowered gradually ' by a gradual retraction of the ram through the gradual control offered by the sloping shoulder 30 and spring 81 as the control knob 20 is turned clockwise from the default position. However the ram may be allowed to rise rapidly by the almost instant full opening of the air passage of the valve acted upon by the steeper sloping cam shoulder 34 to provide maximum air pressure at the second air pilot of the hydraulic valve. In this arrangement, the point of maximum projecting of the cam is circumferentially offset towards the side of the steeper sloping shoulder, as is the case in the illustrated embodiment of Figure 4 and 5.

The second control element 16 and its plunger and valve assembly, in effect form a pneumatic on/off switch. Depressing the outer member 38 of the pushbutton assembly from its non- active position drives the spring-loaded plunger assembly 76 to open the valve 82. The latching of the inner member 40 of the pushbutton assembly. as described above, retains the valve in the open position, until a second depressing releases the inner member and the valve cloees through the urging of spring 54. Second control element may be used to drive another hydraulic valve or alternatively, may directly control a pneumatic actuator, for example to engage the drive gear of a power take off unit, or operate a tail gate for example.

In Use

In use, the pneumatic control module 10 of the Invention may be used to control the air pilot valves of at least one hydraulic device and a pneumatic device from the cabin of a vehicle. Typically, the first control element may be used to control the raising and lowering of a tipper body with the second control element controlling a power take-off unit. The compact arrangement of the dual control elements and the associated compact valve block, provide for convenient in-cab mounting. The absence of projecting levers provides safety from both injury and inadvertent activation. Although the present description has focused the invention in the context of hydraulic and/or pneumatic devices on a typical truck with a tipping load body, it will be understood that the pneumatic control module of the invention may equally be applied to contr.ol of hydraulic and/or pneumatic devices associated with other installations.

If control of additional devices is required, an extended housing such as shown in Figure 6 may incorporate two control modules.

The above describes only some embodiments of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention.

Claims

1. A pneumatic control for activation and control of hydraulic and/or pneumatic equipment; said control combining activation and control of at least a first hydraulic device by rotation of a first control element and control of a second hydraulic or pneumatic device by linear displacement of a second control element relative said first control element.

2. The pneumatic control of claim 1 wherein said first and second control elements are combined in a single control module/ said control module adapted for mounting in a vehicle control cabin,

3. The pneumatic control of claim 1 or 2 wherein said first control element comprises a rotatable, generally cylindrical control knob projecting from said control module; said second control element comprising a pushbutton assembly located within a central aperture of said first control element.

4. The pneumatic element of any one of claims 1 to 3 wherein said first control element includes an internal annular skirt generally depending from said central aperture; said annular skirt having an uneven lower annular portion so as to form a cam.

5. The pneumatic control of claim 3 or 4 wherein said pushbutton assembly of said second control element is retained in an activated depressed position after a first pressing of said pushbutton assembly; said pushbutton assembly returning to a deactivated position when applying a second pressing while in said depressed position.

6. The pneumatic control of any one of claims 3 to 5 wherein said pushbutton assembly comprises an outer member and an inner member; said outer member connected to said inner member by an axially sliding connection; said inner member provided with radially projecting fins; said fins slidingly located in grooves provided in an internal surface of said annular skirt, when said pushbutton is in said deactivated position.

7, The pneumatic control of claim 6 wherein cooperating portions of said outer and inner members are arranged such that a first linear depressing of said outer member induces sufficient linear displacement and rotation of said inner member to disengage said fins from said grooves; said fins rotated to an intermediate position at which said fins engage a recessed rim portion of said skirt.

8. The pneumatic control of claim 6 of 7 wherein a second depressing further rotates said inner member to re-align said fins with said grooves; said fins re-entering said grooves, thereby returning said pushbutton assembly to said deactivated state through urging of a spring element .

9. The pneumatic control of any one of claims 1 to 8 wherein said control module further includes an integrally formed valve block; said valve block including three cylindrical valve chambers; a first cylindrical valve chamber arranged coaxial with said central aperture, a second and third cylindrical valve chamber arranged on either side of said first valve chamber; the arrangement being such that the axes of said second and third valve chambers intersect diametrically opposite points on a lower annular portion of said annular skirt.

10. The pneumatic control of claim 9 wherein each said valve chamber is provided with a spring-loaded plunger assembly; a first spring-loaded plunger assembly of said first valve chamber urged against said inner member of said pushbutton assembly; second and third spring-loaded plunger assemblies of said second and third valve chambers urged against said diametrically opposite points on said lower annular portion of said annular skirt.

11. The pneumatic control of claim 4 wherein the form of said cam of said lower annular portion is arranged with a section projecting below a general plane of the remaining section of said annular portion; said projecting section having an area of maximum projection with sloping shoulder areas extending in each circumferential direction away from said area of maximum projection.

12. The pneumatic control of claim 11 wherein said first control element is arranged to rotate between clockwise and anticlockwise limits; said first control element being in a non activating state when rotated to a mid point between said limits; said maximum area of projection of said cam then positioned between said points of contact of said second and third spring-loaded plungers with said lower edge of said annular skirt.

13. The pneumatic control of claim 11 or 12 wherein a clockwise or anticlockwise rotation of said first control element drives a respective one of said sloping shoulder areas against either said second or said third spring- loaded plunger; said rotation depressing a respective said spring-loaded plunger to open a valve at a lower end of respective said second or third valve chamber; said valve opened to a maximum when said area of maximum projection is coincident with said spring-loaded plunger.

14. The pneumatic control of any one of claims 11 to 13 wherein respective said sloping shoulder areas are asymmetric; shape of said sloping shoulder areas determining differential degrees of rates of opening of respective said air passages, according to the degree of clockwise or anticlockwise rotation of said first control element .

15. The pneumatic control of claim 10 wherein depressing said second control element into said activated state urges said first spring-loaded plunger assembly to open a valve at a lower end of said first valve chamber.

16. The pneumatic control of any one of claims 9 to 15 wherein each said first, second and third cylindrical valve chamber is connected to a common air supply manifold integrally formed with said valve block; said manifold adapted for connection to a compressed air supply.

17. The pneumatic control of any one of claims 9 to 16 wherein each cylindrical valve chamber communicates with an air outlet spigot; each said spigot adapted for connection to an air line for communication with a said hydraulic and/or pneumatic device.

18. The pneumatic control of claim 17 wherein first and second ones of said outlet spigots are connected by air lines to an hydraulic valve block controlling an hydraulic ram; said first control element providing progressive speed control of operation of said ram in extension and retraction.

19. The pneumatic control of claim 17 or 18 wherein a first of said outlet spigots is connected by an air line to pneumatic actuator controlling a power take-off unit of said vehicle; depressing of said second control element pushbutton assembly causing said pneumatic actuator to engage said power take-off.

20. The pneumatic control of any one of claims 1 to 19 wherein said module is adapted for mounting in the control cabin of a vehicle.

21. A method of pneumatic control of hydraulic and/or pneumatic devices of a vehicle; a said hydraulic device requiring gradated control of rate of operation/ a said pneumatic device requiring switching between an activated and a non-activated state; said method including the steps of;

(d) combining a first and second control element in a pneumatic control module,

(e) providing said first control element^' as a rotating element, said rotating element including a cam arranged for gradual opening of either a second or third pneumatic valve,

(f) providing said second control element as a pushbutton assembly; a first pressing of said pushbutton assembly causing linear displacement and opening a first pneumatic valve; said valve remaining open until application of a second pressing of said pushbutton, and

wherein said pushbutton assembly of said second control element is located in a central aperture of said first control element.