US3584705A - Control system for mobile work platforms - Google Patents

Abstract

A control system for mobile work platforms adapted elevationally to position a worker relative to workpieces such as trees in an orchard and the like with such a platform being mounted on a mobile chassis for elevational and rotational movement providing a plurality of flexible push-pull control cables extended between control levers on the platform and suitable control valves for the powered members on the chassis with the cables being capable of twisting within their own lengths to accommodate substantially 360* rotation but not continuous rotation of the platform relative to the chassis and a quick-change two-speed drive selector mechanism for the mobile chassis to adapt the mobile platform for operation under a variety of conditions.

Description

United States Patent [72] lnventor Carl W. Ruegg 10639 S. Golden State Boulevard, Selma, Calif. 93662 [21] Appl. No. 841,340 [22] Filed July 14, 1969 [45] Patented June 15, 1971 [54] CONTROL SYSTEM FOR MOBILE WORK PLATFORMS 3 Claims, 11 Drawing Figs.

[52] US.Cl 182/13, 182/2, 74/242.l5 [51] lnt.Cl 866111/04 [50] Field ofSearch 182/2, 141, 13, 63; 74/217, 242.15; 180/72, 79.2

[56] Rel'erenca Cited UNITED STATES PATENTS 2,778,235 1/1957 Amonsen 74/242.15

Primary Examiner-Reinaldo P. Machado Attomey- Huebner & Worrel ABSTRACT: A control system for mobile work platforms adapted elevationally to position a worker relative to workpieces such as trees in an orchard and the like with such a platform being mounted on a mobile chassis for elevational and rotational movement providing a plurality of flexible push-pull control cables extended between control levers on the platform and suitable control valves for the powered members on the chassis with the cables being capable of twisting within their own lengths to accommodate substantially 360 rotation but not continuous rotation of the platform relative to the chassis and a quick-change two-speed drive selector mechanism for the mobile chassis to adapt the mobile platform for operation under a variety of conditions.

PATENTEU JUN} 5197! SHEET 1 OF 3 CARL PM RUEGG INVENTOA M I JM AWDPNEVS PATENTED JUN? 5197: 3.5841705 sum 2 BF 3 c r 5ma 80 CARL W. RUEGG /N 1/5 N r01? 4 A T7URNEVS PATENTEU JUN SHEET 3 OF 3 CARL W. RUEGG /N VEN TOP A TTO/PNEVS CONTROL SYSTEM FOR MOBILE WORK PLATFORMS BACKGROUND OF THE INVENTION The control system of the present invention is particularly adapted for use on mobile work platforms and the like similar to that shown in 1.1.8. Pat. No. 3,127,952. Such a structure provides a mobile chassis having a substantially upright hollow mast rotatably mounted on the chassis in supporting relation to an elongated platform supporting boom which is elevationally positionable relative to the mast and the chassis. Such structure further includes a solid-type control linkage between the control levers on the platform and the hydraulic valves on the chassis for controlling the various powered movements of the platform. While providing precise control of such powered platform movements, it has been found desirable to simplify the control while permitting substantially 360 rotation of the platform and mast relative to the chassis. Further, it is highly desirable to avoid utilizing the unsightly and cumbersome hydraulic hoses which are conventionally employed in similar control systems. It is evident that in order to permit substantially unrestricted movement of the platform, the hydraulic hoses, where employed, need to have sufficient slack to ac .xcommodate all such platform movements. Frequently, the

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an improved control system for mobile work platforms and the like.

Another object is to provide such an improved control system which eliminates the unsightly and movement-restricting hoses of conventional hydraulic control systems.

Another object is to provide an improved control system for mobile work platforms which completely eliminates the complicated solid control linkages conventionally employed.

Another object is to provide an improved control system of the character described which may be easily, conveniently and economically manufactured and installed on new or existing mobile work platforms and economically maintained.

Another object is to provide an improved control system which permits substantially unrestricted elevational and rotational movement of the worker support platform relative to the mobile chassis.

Another object is to provide an improved control system which utilizes a plurality of flexible push-pull cables which are capable of twisting within their own lengths sufficiently to accommodate substantially 360 rotation but not continuous rotation of the platform.

Another object is to provide a control system for mobile work platforms which incorporates a quick-change, two-speed drive selector mechanism for the mobile chassis in order easily to adapt the platform for operating under a wide variety of conditions.

Another object is to provide an improved control system in which the two-speed drive selector mechanism has an adjustably positionable drive motor and an invertible overcenter locking member which is easily and conveniently manipulated without requiring the removal of any components thereof from the chassis.

Other objects and advantages of the present invention will subsequently become more clearly apparent upon reference to the following description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevation of a mobile work platform showing the worker support platform thereon disposed in an elevated position incorporating the improved control system of the present invention.

FIG. 2 is a somewhat enlarged top plan view of the mobile chassis showing a portion of the improved control system thereon with the boom arm and worker support platform removed.

FIG. 3 is a somewhat enlarged fragmentary front elevation of the mobile chassis and a portion of the control system thereon.

FIG. 4 is a somewhat enlarged fragmentary top plan view of the worker support platform and control lever panel of the control system of the present invention.

FIG. 5 is a somewhat enlarged fragmentary side elevation of the control lever panel of FIG. 4.

FIG. 6 is a somewhat enlarged front elevation of the control lever panel of FIGS. 4 and 5.

FIG. 7 is a somewhat enlarged fragmentary top plan view of a quick-change, two-speed drive selector mechanism for the control system which is diagrammatically shown on FIG. 2.

FIG. 8 is a somewhat enlarged longitudinal vertical section through the chassis, taken generally on line 8-8 of FIG. 7, showing the two-speed drive selector mechanism in front elevation and disposed in a low-speed position.

FIG. 9 is a somewhat fragmentary top plan view of the twospeed drive selector mechanism disposed in a high-speed position.

FIG. 10 is a somewhat enlarged fragmentary front elevation of the two-speed drive selector mechanism disposed in the high-speed position of FIG. 9.

FIG. 11 is a somewhat enlarged, fragmentary side elevation of the two-speed drive selector, showing the drive motor and mounting therefor.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to the drawings, a mobile work platform, incorporating the improved control system of the present invention, provides amobile chassis 10 having abox section frame 11 which is supported for ground traversing movement by a pair ofsteerable wheels 12 and a pair ofdrive wheels 14. The drive wheels include driven sprockets l6 individually connected to a pair ofdrive sprockets 17, mounted on the opposite ends of arotatable jack shaft 19, byendless chains 20. The jack shaft is mounted in transversely disposed relation on theframe 11 of the chassis by a pair of pillow mountedbearing blocks 22 disposed adjacent to the ends of the shaft. The jack shaft is driven by anhydraulic motor 23 on the chassis through a chain and sprocket assembly which will be described in greater detail subsequently.

Thesteerable wheels 12 are mounted on anaxle 24 which is borne by theframe 11 by means of a pair of wheelmounting spindle arms 25 interconnected by a connecting rod 26. Anhydraulic steering jack 28 is extendibly retractably mounted between the frame and intermediate the ends of the connecting rod in controlling relation to thesteerable wheels 12. Anelongated draft tongue 30 is connected to the axle and connecting rod in longitudinally extended relation from the frame for steering the wheels during towing of the mobile chassis behind a truck, tractor, or the like, not shown.

Acircular turntable 32, having atoothed periphery 33, is rotatably mounted on theframe 11 of the chassis for supporting an upwardly extendedhollow mast 35 in concentric relation thereon. The turntable is driven by anhydraulic motor 36 supported on the frame which has a sprocket 37 engaging anendless chain 38 extended around thetoothed periphery 33 of the turntable. A stop dog 40 is formed on the upper surface of the turntable for engagement with astop arm 42 borne by the frame and disposed in overlying relation to the turntable in the path of movement of the stop dog 40 to limit rotation of the turntable through an arc of travel of approximately 360.

An elongated hollowplatform supporting boom 45 is pivotally mounted at one end of the upper end of themast 35 and provides adistal end 46 pivotally supporting awork platform 50. Anelongated guide rod 52 is extended in parallelogram relation to the boom arm for connection at one end to the platform and at its other end to anupward extension 54 on themast 35,'in order to maintain the platform in a substantially horizontal position throughout its entire range of elevational swinging movement. Such movement is effected by anhydraulic jack 55 having acylinder end 56 pivotally mounted on apedestal 57 on the mast and anopposite rod end 58 pivotally mounted on the boom. An elongatedcounterweight mounting frame 60 is outwardly extended from the mast intermediate its ends in opposed relation to the boom for counterbalancing the load on theworker support platform 50.

Anengine 62 is mounted on theframe 11 of the chassis and has a drive shaft connected to a mainhydraulic pump 63. The pump is fed hydraulic fluid from a reservoir disposed within the frame members of the chassis through a line 64 and which discharges fluid under pressure through aline 65 to aflow divider valve 66. A plurality ofhydraulic hoses 70, 71, 72 and 73 are extended from the flow divider valve for individual connection to a plurality ofcontrol valves 75, 76, 77 and 78, respectively, disposed on the frame. These valves are connected through suitable hydraulic hoses, not shown, respectively to thedrive motor 23, thesteering jack 28, theturntable drive motor 36, and theboom elevating jack 55.

Theworker support platform 50, as best shown in FIGS. 4, 5 and 6, provides afloor 80 having a front controllever mounting panel 82 upwardly extended therefrom and providing oppositely spaced substantiallyparallel sides 83. A plurality of hand control levers 85, 86, 87 and 88, having respective operational association with thecontrol valves 75, 76, 77 and 78, are pivotally mounted on thecontrol panel 82. Thecontrol lever 85 is associated with the control valve 75 for controlling rotational movement of theboom 45 andworker support platform 50. Thecontrol lever 86 is associated with thecontrol valve 76 on the chassis which controls the ground traversing movement of the chassis. Thecontrol lever 87 is associated with the control valve 77 on the chassis for operation of thehydraulic steering jack 55 for steering thewheels 12 of the chassis. Thecontrol lever 88 is associated with thecontrol valve 78 for raising and lowering theboom 45 and theworker support platform 50.

The control levers are grouped in pairs withlevers 85 and 86 providinglower ends 90 and 91, respectively, rotatably mounted on apivot shaft 93 journaled in a sleeve bearing 94 in one of thesides 83 of thecontrol panel 82. The control levers 87 and 88 provide lower ends 96 and 97, respectively, which are mounted on apivot shaft 98 which is journaled in asleeve bearing 99 through theopposite side 83 of thecontrol panel 82. As best shown in F IG. 5, each of the lower ends of the control levers has a right-angularly related bellcrank arm 101 for substantially vertical swinging movement about its respective pivot shaft during fore and aft movement of the upper ends of the control levers.

An elongated flexible push-pull cable 105 is connected to each of the bellcrank arms 101 and at its opposite end is connected to one of the control valves on the chassis. Each of the cables provides an outerflexible sheath 106, the upper ends of which are fastened to abracket 107 secured to thecontrol panel 82. An elongated substantiallystiff wire rod 110 is extended in controlling relation through the sheath for connection at its upper end to its respective bellcrank arm 101 by a connector member 112, as shown in FIG. 5. The sheath effectively confines and supports the rod so as to render it capable of transmitting a push-pull force without buckling. Each of the cable sheaths provides an opposite lower end, as best shown in FIG. 3, which is rigidly connected by abracket 114 secured to achannular frame member 115 of thechassis 10. Thecontrol rod 110 includes a lower end outwardly extended from the sheath which is pivotally connected by abracket 117 to the lower end of abellcrank lever 120. The bellcrank lever is pivotally mounted intermediate its ends on the frame of the chassis and provides an opposite end pivotally connected to a rod 122 depending from each of thecontrol valves 75, 76, 77 and 78 on the chassis.

A pair offoot control pedals 125 pivotally are mounted above thefloor 80 of theworker support platform 50 which may be utilized by the operator alternatively with the boom swing control lever 75 and the boom elevationalcontrol lever 78. As best shown in FIG. 5, each of the foot pedals includes aforward toe portion 126 and arearward heel portion 127 for respectively simulating fore and aft movement of their corresponding control levers. The pedal includes a downwardly extendedsupport arm 128 which is pivotally mounted on across shaft 130 below the floor of the platform. A motion transfer linkage assembly 132 is disposed in interconnecting relation between the foot pedal and the pivot arm 101 of the control levers 75 and 78, respectively. This linkage includes a substantially upright connectingrod 133 pivotally mounted at its upper end on the pivot arm 101 of the control lever and at its lower end to anarm 134 extended from apivot shaft 135. A substantiallyupright arm 137 is extended from the pivot shaft in axially spaced relation from thearm 134 for pivotally mounting one end of an elongated connecting rod 140 having its opposite end pivotally connected to anupright arm 142 on the cross-shaft 130 of the foot pedal.

A foot control pedal is also alternatively provided for controlling the chassis drive with the pedal having a substantially L-shapedsupport arm 152 extended through anopening 153 in thecontrol panel 82 closely adjacent to thefloor 80. The arm is upwardly extended from anelongated sleeve 154 rotatably mounted on thepivot shaft 135 which includes alever arm 156 extended therefrom to provide a pivotal connection for the lower end of a connectingrod 157 connected at its upper end to the pivot arm 101 of the chassisdrive control lever 86.

A two-speed drive selector mechanism of the present invention is shown in FIGS. 7 through 11 of the drawings in association with thechassis drive motor 23. Such mechanism includes a drivensprocket 162 disposed on thejack shaft 19 on the chassis and a relativelysmaller sprocket 163 mounted on the jack shaft in axially spaced relation to the relativelylarger sprocket 162. Thedrive motor 23 has adrive sprocket 165 of a predetermined size mounted thereon with the motor being adjustably mounted for movement between alternate positions with its drive sprocket aligned in coplanar relation with thesprockets 162 and 163. This is accomplished by mounting the drive motor on a substantially upstanding mounting plate which has a pair of upper connector bores 172 and 173 and a lower elongatedbored sleeve 175. The sleeve is axially slidably mounted upon anelongated shaft 177 having opposite screw-threaded ends extended through a pair of spaced substantially uprightparallel brackets 178 by a pair oflock nuts 179 screw-threadably received on each end of the shaft. An elongatedendless chain 182 is alternately trained about the drive sprocket and the drivensprockets 162 and 163 on thejack shaft 19 for providing the desired two-speed drive to thedrive wheels 14 of thechassis 10.

Thedrive chain 182 is releasably tensioned about themotor drive sprocket 165 and thesprockets 162 and 163 by anovercenter locking mechanism 185. This mechanism includes a substantiallyupright pedestal 186 which is secured to theframe 11 of the chassis adjacent to thedrive motor 23. The pedestal has an outwardlyextended flange 187 adjacent to its upper end which mounts an elongated spring-loadeddetent 190 which has a plunger 192 normally outwardly extended therefrom. Acircular disc 195 is rotatably mounted on the upper end of the pedestal in substantially facing sliding relation to theflange 187 and provides anopening 196 therethrough alignable with thedetent 190 in receiving relation to the detent plunger 192. The disc further includes aconnector bore 197 in substantially diametrically opposed relation to theopening 196 and anelongated handle 198 extended therefrom for manual rotation of the disc upon the pedestal.

Anelongated connector rod 200 is disposed between thedisc 195 and the mountingplate 170 of thedrive motor 23. The connector rod has an intermediate body portion 202 providing a rigid hooked end 203 and an opposite invertiblehooked end 204. Theinvertible end 204 is screw-threadably mounted within the body in axial extension therefrom and has alock nut 205 for constraining the hooked end in any desired direction from the body. The hooked end 203 of the connector rod is releasably extendible through either of the connector bores 172 of themotor mounting plate 170 and the opposite hookedend 204 is releasably extendible through the connector bore 197 in thedisc 195 of thelocking mechanism 185 for holding the motor in its chain tensioning position with respect to either of the drivensprockets 162 or 163.

OPERATION The operation of the described embodiment of the subject invention is believed to be clearly apparent and is briefly summarized at this point. Prior to use, theappropriate drive sprocket 162 or 163 is selected to provide the desired earth traversing speed of the chassis for the particular job involved or for various ground conditions which may be encountered in an orchard or the like. When the mobile work platform is to be used on relatively soft terrain, the drivensprocket 162 is utilized, as shown in FIG. 7 of the drawings. In such position, theconnector rod 200 is disposed with the rigid hooked end 203 thereof extended through the connector bore 172 of themotor mounting plate 170 with the control handle 198 anddisc 195 rotated to the left from the position shown in FIG. 8 in order to provide sufficient slack in thedrive chain 182 to permit its installation about thedrive sprocket 165 on the motor and the drivensprocket 162. The invertiblehooked end 204 of the connector rod is positioned for extension in the same direction as the rigid hooked rod 203 from the body and thelock nut 205 tightened to hold it in the desired position. Thehooked end 204 is extended through the connector bore 197 of the rotatable disc and the handle is returned to the right, as viewed in FIG. 8, to its overcenter locking position dependably to hold the chain in tensioned relation about the sprockets.

If the mobile work platform is to be employed on a substantially hard, smooth surface, the drivensprocket 163 is employed to provide a greater reduction and correspondingly faster speed between the motor and thejack shaft 19. Such speed change is easily and conveniently accomplished by returning the control handle 198 anddisc 195 to the left, as viewed in FlG. 0, to provide sufficient slack in thedrive chain 182 to permit its removal from the drivensprocket 162 and to permit the removal of theconnector rod 200. Thelock nut 205 is loosened to permit theinvertible end 204 of the rod to be positioned laterally from the connector rod in a direction opposite to the rigid hooked end 203 as shown in FIGS. 9 and 10. Themotor mounting sleeve 175 is axially slid along theshaft 177 from the position shown in FIG. 11 to the right in order to align thedrive sprocket 165 with thesmallersprocket 163 on thejack shaft 19. In such position, the rigid hooked end 203 of the connector rod is extended through the connector bore 173 of the drive motor of the drivemotor mounting plate 170 and the opposite invertiblehooked end 204 thereof is again extended through the connector bore 197 in thedisc 195. The control handle 198 is again rotated in a clockwise direction to the right, as shown in FIG. 10, to a position rocking the drive motor farther to the right than in its previous drive position of FIG. 8 again to tension thedrive chain 182 about the aligned sprockets. The overcenter relationship between the opposite hooked ends 203 and 2040f the connectingrod 200 and the pivot shaft of thedisc 195 on the upper end of the pedestal ensures proper tensioning of the drive chain. The detent plunger 192 which is received within theopening 196 in the disc positively precludes return movemom of the control handle until the plunger is manually retracted therefrom.

During use, the mobile work platform of the present invention is capable of supporting a workman upon theworker support platform 50 which is elevationally positionable through a wide variety of precisely selectable working positions. Thechassis 10 andplatform boom 45 are precisely controllable by the operator from theworker support platform 50 by manipulation of the hand control levers 85, 86, 87 and 88 thereon or by alternate manipulation of thefoot pedals 125 and 150. As described, during movement of the control levers, thewire rods 110 of the control cables extending between the levers and thecontrol valves 75, 76, 77 and 78 on the chassis for controlling the various powered components on the machine are constrained by their :respectiveouter cable sheaths 106 to axial sliding movement therein to transmit the lever movement precisely to the appropriate control valve. The control cables are conveniently extended downwardly through thehollow boom arm 45 and through thehollow mast 35 so that they are substantially hidden and protected against damage from being struck by foreign objects and from the weather. As described, each of thecontrol cables 105 is rigidly connected at its opposite ends respectively to the control levers and to the control valves on the chassis. However, the cables inherently provide sufficient flexibility between their opposite ends easily to accommodate substantially 360 rotation but not continuous rotation of the boom arm and mast upon theturntable 32 relative to the chassis without impairing the control of the boom arm rotational control valve and lever or any of the other described control levers which are fully operational in any of the various platform positions.

In view of the foregoing, it is readily apparent that the structure of the present invention provides an improved control system for mobile work platforms and the like which may be easily, conveniently and economically manufactured and installed to permit substantially unrestricted elevational and rotational movement of the worker support platform relative to the mobile chassis throughout a predetermined operational range. The plurality of control cables between the control levers on the platform and the control valves on the chassis are capable of twisting within their own lengths substantially to accommodate 360 rotation of the platform with the quickchange two-speed selector mechanism on the chassis permitting the machine to be adapted for operation under a wide variety of operating conditions on various support surfaces.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized. that departures may be made therefrom within the scope of the invention.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A control system, for a work platform having a mobile chassis comprising; an alternatively selectable two-speed chassis drive mechanism providing a drive motor; a chassis drive shaft; a pair of different sized driven members disposed in axially spaced relation on said drive shaft; means mounting said drive motor for axial sliding and limited rotational movement between alternate positions respectively aligned with said driven members; means interchangeably drivingly connecting said motor and said driven members; and overcenter locking means for releasably holding said drive motor in said alternate positions providing a pedestal mounted on said chassis in spaced relation to said drive motor; a lever pivotally mounted on said pedestal and an elongated link having rotatably invertible hooked ends releasably interconnecting said drive motor and the lever in said alternate motor positions in tensioning relation to said means drivingly connecting said motor and said driven members.

2. The control system of claim 1 in which said motor mounting means includes a connector plate having a pair of spaced openings for releasably interchangeably receiving said one of said hooked ends of said link, and an opening in said lever for releasably receiving said other hooked end of the link.

3. A multispeed drive mechanism comprising a support, a drive shaft mounted for rotation on said support, a plurality of driven members with which it is aligned, lock means mounted on the support releasably holding said drive motor in said selected positions, and reversible link means releasably interconnecting said drive motor and said lock means in each of said selected positions.

Claims (3)

1. A control system, for a work platform having a mobile chassis comprising; an alternatively selectable two-speed chassis drive mechanism providing a drive motor; a chassis drive shaft; a pair of different sized driven members disposed in axially spaced relation on said drive shaft; means mounting said drive motor for axial sliding and limited rotational movement between alternate positions respectively aligned with said driven members; means interchangeably drivingly connecting said motor and said driven members; and overcenter locking means for releasably holding said drive motor in said alternate positions providing a pedestal mounted on said chassis in spaced relation to said drive motor; a lever pivotally mounted on said pedestal and an elongated link having rotatably invertible hooked ends releasably interconnecting said drive motor and the lever in said alternate motor positions in tensioning relation to said means drivingly connecting said motor and said driven members.

2. The control system of claim 1 in which said motor mounting means includes a connector plate having a pair of spaced openings for releasably interchangeably receiving said one of said hooked ends of said link, and an opening in said lever for releasably receiving said other hooked end of the link.

3. A multispeed drive mechanism comprising a support, a drive shaft mounted for rotation on said support, a plurality of driven members of individually distinctive sizes disposed in axially spaced relation on said drive shaft, a drive motor mounted on said support for limited axial sliding and rotational movement between selected positions individually respectively aligned with said driven members, means interchangeably drivingly connecting said drive motor and said driven members with which it is aligned, lock means mounted on the support releasably holding said drive motor in said selected positions, and reversible link means releasably interconnecting said drive motor and said lock means in each of said selected positions.

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