WO2009059347A1

WO2009059347A1 - Pedal assembly

Info

Publication number: WO2009059347A1
Application number: PCT/AU2007/001705
Authority: WO
Inventors: Geoffrey Allan Davis; Eric Owen
Original assignee: Cavotec Australia Pty Ltd
Priority date: 2007-11-08
Filing date: 2007-11-08
Publication date: 2009-05-14

Abstract

There is provided a pedal assembly comprising a housing (10) with a foot plate (11) on top of an open-bottomed machinery space (16) closed by a removable cover plate. Main (21) and outer (22) bearing carriers journal a beam (24) on a rocker shaft (23). The outer ends of the beam (24) are universally-jointed to respective left (25) and right (26) pedal links, each in turn articulated to respective left (27) and right (32) pedals. A rack sector (34) is mounted on the beam (24) and engages a pinion gear (35) mounted of the end of a controller shaft (36), which cooperates via cams with a pack of contactors (37) to generate switch signals. The outer end of the controller shaft mounts a resolver assembly (40) to provide a proportional control signal at the control socket assembly (20) via signal organizer (41) and multi-core data cable (42).

Description

PEDAL ASSEMBLY

FIELD OF THE INVENTION

This invention relates to a pedal assembly. The invention has particular application to pedal assemblies for slew control of draglines and like plant and equipment, and for illustrative purposes reference will generally be made to such an application. However, it is to be understood that this invention could be used in other equipment, such as in stripping shovels, earthmoving machinery, cranes, turrets of military tanks and other AFVs, gun emplacements and the like.

PRIOR ART

The following prior art forms part of the public knowledge in respect of draglines. However, the described art does not form part of the common general knowledge of the art merely by virtue of it being described herein.

Draglines used in mining operations utilize a slewing or swing boom arrangement controlled from an enclosed cabin including an operator console.

The console generally includes control panels having one or more joystick controls, buttons and switches to control hoist, drag and drop functions, and a pedal assembly to control the slewing or swing action of the dragline boom. The cabin is generally mounted to slew with the boom to provide the operator with straight-ahead vision of the business end of the boom. The pedal assembly comprises interconnected and opposed left and right foot pedals, the left pedal being pushed down to raise the right pedal and swing the boom left and wee versa.

Known swing pedal systems may include an assembly mounted through the cabin floor whereby a pedal assembly includes a gearbox having an output shaft passing into a control housing mounting rotary and/or cam operated control elements to be operated by the shaft. At least the control housing portion of the assembly may be located below the floor of the cabin. Servicing may be problematic because of confined space and accessibility to the gear controls due to positioning of the gear control system, and may require the removal of the floor of the cabin, dismantling of the gear controls or repair of parts off site causing extended downtime.

One solution to the serviceability issue has the housing mounted within the cabin on a flat lower plate base. The left and right pedals are pivoted at their heel ends essentially at cabin floor level on the lower base plate with the housing located between the pedals.

Left and right pedal shafts pass through respective end walls of the housing above the base plate and are operated by the pedals via respective roller crank arms, the lost motion rollers operating on the underside of the pedals. The inner ends of the shafts are coupled to each other in opposed rotation by respective bevel gears acting through a reversing idler bevel gear. At least one of the shafts is acted on by a counter spring to bias the coupled shafts and their respective pedals to a neutral position.

An operating shaft is mounted parallel to the pedal shafts and is driven by a pedal shaft sector gear acting on an operating shaft pinion gear. The operating shaft may operate rotary devices such as rotary potentiometers and rotary transducers, and/or cam operated devices such as microswitches.

This arrangement has the disadvantage of intrusion into the cabin space. In addition, the location of the pedals at either side of the housing means the operator must adopt an excessively wide stance if the housing is to be of sufficient width to accommodate the reversing gear train assembly, counter spring assembly, and operating shaft and devices assembly. The arrangement uses a lot of bearings and bushes. The reversing bevel gear arrangement has, at this scale, a significant lash between the left and right pedal shafts, resulting in calibration difficulties for some rotary devices.

DESCRIPTION OF THE INVENTION

As used herein terms such as "front", "back", "base", "top", "side", "bottom", "left", right", "end", and like relative terms refer to the orientation or configuration of a swing pedal assembly or other related apparatus when used in a dragline or like plant or equipment. It is to be understood that these terms do not limit the present invention to any specific orientation or configuration of the invention.

In the specification the terms "comprising" and "containing" and their parts of speech shall be understood to have a broad meaning similar to the term "including" and its corresponding parts, and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

This invention in one aspect resides in a pedal assembly including a housing having a top wall adapted to support left and right pedals connected by links passing through the top wall to respective ends of a rocking beam mounted on a pivot within the housing, a ring gear rack sector coaxially mounted on the beam and spaced from the pivot, an operating shaft mounted in the housing and pinion-driven by the rack section, and one or more signal generating devices operated by said operating shaft. The housing may be adapted to be mounted through an aperture in a cabin floor. Preferably the housing is mounted entirely within the cabin such as by mounting on the cabin floor. The housing may be mounted to the operator console, cabin floor or other structure by a mounting bracket or the like. The housing may be mounted to the cabin on an adjustable mounting allowing one or more adjustment along or about X, Y and Z axes. For example, there may be provided a mounting allowing adjustment along one or more of the Y-axis for leg reach adjustment, rotation about the X-axis for pedal rake adjustment, and/or along the Z-axis for height adjustment. The pedals may be connected to the top wall by any means allowing alternating push-pull operation of the rocking beam via the links. For example, the pedal may be pivoted transversely about a pedal mounting pivot. The pedal mounting pivot may be at the pedal heel or may be further up the pedal to provide a more ergonomic pedal action. The link apertures through the top wall may be dust-sealed by means of a dust boot disposed about the link aperture and either closed to the link or closed to the underside of the pedal.

The links may be articulated to the pedal and beam respectively by any suitable means. In order to accommodate the dynamic geometry of a link between the pedal and beam each pivoting at different radii and in perpendicular planes, the links are preferably articulated by universal-joint rod ends. The link length may be adjustable on the rod ends.

The rocking beam may be pivoted about a fixed shaft on a bush or bearing, or may be constrained to pivot on an open fulcrum such as a knife edge.

Alternatively, the rocking beam may be fixed to a shaft that is mounted by bearing or bush to a bearing carrier mounted to the housing. Where the rocking beam is fixed to the shaft, the shaft may be extended and be used to operate switches or other rotary or cam operated devices.

The shaft and/or beam may be associated with biasing means adapted to bias the shaft and beam, and thus the pedals, to a centered or neutral position. For example the shaft may mount a reaction member against which a spring interposed between the member and a mount associated with the housing may act to centre the pedal mechanism. In particular embodiments there is provided a cross bar mounted to or through the shaft, each end of the bar acting to compress a respective spring when a corresponding pedal is depressed, and acting to recover the centre position when the pedal is released. Preferably, the springs are both in partial compression at the center or neutral position of the pedal mechanism.

The ring gear rack sector coaxially mounted on the beam is preferably disposed symmetrically about a rest or centre position of the beam. By this means the beam moves through equal actions for alternate operation of the left and right pedals. The rack teeth may be straight or helically cut to mesh with a correspondingly cut pinion gear teeth.

The operating shaft pinion-driven by the rack section is preferably supported by at least one bush or bearing in order that bending moment transverse the shaft axis is not translated to sensitive rotary devices mounted on or operated by the operating shaft. The use of a beam drive arrangement and the ability to select from a wide range of gear ratios by selecting the radius of the ring gear rack sector and the gear ratio between the rack and the pinion results in control over the width and height of the housing. This has a direct impact on the ergonomic and serviceability qualities of the pedal. The pedal spacing and height may be ergonomically chosen, while ensuring that the pedal assembly is wholly containable above the floor of the cabin.

One advantage of preferred embodiments is that the top mounting of the pedals enables the pedals to be at least partially over the top of the mechanism in the housing, thus allowing a narrower stance on the pedals than the prior art in- cabin pedal assemblies.

The signal generating device or devices may be selected from rotary devices or cam-operated devices. The signal generating device or devices may comprise a controller for a dragline or the like. The controller may include various microswitch-based contactors, rotary transducers and potentiometers, limit switches, calibrating switches or the like. The signal generating device may function as an encoder or resolver.

The devices preferably include a self indexing arrangement whereby the control elements reset the control centre position to the pedal physical centre or neutral position. For example an electronic resolver may include a microswitch which is acted on by a cam at the physical centre or neutral point of the pedal mechanism and acts to resets the resolver the zero position at this point.

The controller may include means to translate the received signal into instructions and to transmit the instructions to actuate a desired movement of the device, typically the swing movement or slew of a dragline or shovel bucket.

The signal generating device may include multiple contactors arranged along the operating shaft to form a contactor assembly. For example, the contactor assembly may include at least three contactors. Where it is desirable to use more contactors, such as at least six contactors, to provide more precise signals, there may be provided a second or subsequent ring gear rack sector coaxially mounted on the beam and spaced from the pivot, with its own operating shaft pinion-driven by the rack section.

BRIEF DESCRIPTION OF DRAWINGS In order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate an embodiment of the invention and wherein:

FIG. 1 is a rear view of a pedal assembly according to the present invention; FIG. 2 is a bottom plan view of the pedal assembly of FIG. 1 , with the bottom cover removed to show the workings;

FIG. 3 is a side view of the apparatus of FIG. 1 ; and FIG. 4 is a bottom, front perspective view of the apparatus of FIG. 1 , cut away to show the internal workings and partially disassembled for clarity.

DESCRIPTION OF THE EMBODIMENTS

In the figures there is provided a pedal assembly comprising a housing 10 closed across its upper surface by a foot plate 11. The housing 10 has a rear wall 12 integral with the foot plate 11 , side walls 14 and front wall 15 to form an open- bottomed machinery space 16. The open bottom of the machinery space is closed and dust-sealed by removable cover plate, removed in FIG. 2.

The foot plate 11 extends laterally of the side walls 14 and rearward of the rear wall 12. The front wall 15 has a service handle 17 mounted on it. The rear wall mounts a control socket assembly 20 adapted to receive a control cable. A main bearing carrier 21 is mounted to the underside of the foot plate 11 within the housing and is spaced from an outer bearing carrier 22 mounted to the inside of the front wall 15. A rocker shaft 23 is journalled to the respective bearing carriers 21 , 22. A beam 24 is rigidly mounted to the rocker shaft 23 within the space between the respective bearing carriers 21 , 22. The outer ends of the beam 24 are universally-jointed to respective left 25 and right 26 pedal links. The left pedal link 25 is articulated to the underside of a left pedal 27 pivoted to the foot plate 11 by pedestals 30 via pedal stand-offs 31. Similar pedestals 30 and standoffs 31 mount a right pedal 32 connected to the beam 24 by the right pedal link 26. The beam 24 is maintained in its centered position at rest by a centering bar 33 rigidly mounted on the shaft, each end of which mounts a respective centering spring (not shown) acting between the bar 33 and the underside of the foot plate 11.

Radially spaced from the rocker shaft 23 along the right arm of the beam 24 is a coaxially mounted, primary ring gear rack sector 34 disposed symmetrically about a rest or centre position of the beam 24. The rack sector 34 engages a pinion gear 35 mounted of the end of and driving a controller shaft 36. The controller shaft 36 cooperates via cams with a pack of contactors 37 to generate switch signals. The outer end of the controller shaft mounts a resolver assembly 40 to provide a proportional control signal at the control socket assembly 20 via signal organizer 41 and multi-core data cable 42.

Radially spaced from the rocker shaft 23 along the left arm of the beam 24 is a coaxially mounted, secondary ring gear rack sector 43 disposed symmetrically about the rest or centre position of the beam 24. The rack sector 43 engages a pinion gear 44 mounted of the end of and driving a secondary controller shaft 45. The controller shaft 45 cooperates via a cam with a secondary contactor 46 to generate a switch signal. The outer end of the secondary controller shaft 45 mounts an encoder assembly 47 to provide a control signal via a bridging connector to the signal organizer 41.

It will of course be realised that while the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein set forth.

Claims

The Claims Defining the Inventions are as Follows:

1. A pedal assembly including a housing having a top wall adapted to support left and right pedals connected by respective links passing through the top wall to respective ends of a rocking beam mounted on a pivot within the housing, a ring gear rack sector coaxially mounted on the beam and spaced from the pivot, an operating shaft mounted in the housing and pinion-driven by the rack section, and one or more signal generating devices operated by said operating shaft.

2. A pedal assembly according to claim 1, wherein the housing is adapted to be mounted through an aperture in a cabin floor.

3. A pedal assembly according to claim 1 , wherein the housing is adapted to be mounted entirely within the cabin such as by mounting on the cabin floor.

4. A pedal assembly according to claim 1 , wherein the housing is adapted to be mounted to an operator console, cabin floor or other structure by a mounting bracket.

5. A pedal assembly according to claim 4, wherein the housing is mounted to the cabin on an adjustable mounting allowing one or more adjustment along or about X, Y and Z axes.

6. A pedal assembly according to claim 1 , wherein the pedals are each pivoted transversely about respective pedal mounting pivots.

7. A pedal assembly according to claim 1 , wherein the links pass through respective apertures through the top wall, the apertures being dust-sealed by means of a dust boot disposed about the link aperture,

8. A pedal assembly according to claim 7, wherein the dust boot has its upper end closed to a structure selected from the link and the underside of the pedal.

9. A pedal assembly according to claim 1 , wherein the links are preferably articulated to the pedal and beam respectively by universal-joint rod ends.

10. A pedal assembly according to claim 1 , wherein the rocking beam is fixed to a shaft that is mounted by bearing or bush to a bearing carrier mounted to the housing.

11. A pedal assembly according to claim 10, wherein the shaft mounts a cross bar, each end of the bar acting to compress a respective spring when a corresponding pedal is depressed, and acting to recover the centre position when the pedal is released.

12. A pedal assembly according to claim 1 , wherein there are one or more ring gear rack sectors coaxially mounted on the beam and driving respective operating shafts.

13. A pedal assembly according to claim 12, wherein the ring gear rack sector coaxially mounted on the beam is disposed symmetrically about a rest or centre position of the beam.

14. A pedal assembly according to claim 1, wherein the ring gear rack sector teeth are selected from straight or helically cut teeth to mesh with correspondingly cut pinion gear teeth.

15. A pedal assembly according to claim 1 , wherein the operating shaft pinion- driven by the rack section is supported by at least one bush or bearing in order that bending moment transverse the shaft axis is not translated to sensitive rotary devices mounted on or operated by the operating shaft.

16. A pedal assembly according to claim 1 , wherein the signal generating device or devices are selected from rotary devices or cam-operated devices.

17. A pedal assembly according to claim 16, wherein the signal generating device or devices includes one or more of an encoder or resolver.

18. A pedal assembly according to claim 16, wherein at least one said device includes a self indexing arrangement whereby device resets the device-centre position to the pedal physical centre or neutral position.

19. A pedal assembly according to claim 1, connected to a controller including means to translate the signal into instructions and to transmit the instructions to actuate a swing movement of a dragline.

20. A pedal assembly according to claim 16, wherein the signal generating device includes multiple contactors arranged along the operating shaft to form a contactor assembly.