US3187913A

US3187913A - Implement position control mechanism

Info

Publication number: US3187913A
Application number: US276913A
Authority: US
Inventors: Don S Strader; Robert G Luft
Original assignee: Frank G Hough Co
Current assignee: Frank G Hough Co
Priority date: 1963-04-30
Filing date: 1963-04-30
Publication date: 1965-06-08
Anticipated expiration: 1982-06-08

Description

June 8, 1965 0. s. STRADER ETAL 3,187,913

IMPLEMENT POSITION CONTROL MECHANISM Filed April 30, 1963 2 Sheets-Sheet 1 June 8, 1965 D. s. STRADER ETAL 3,187,913

IMPLEMENT POSITION CONTROL MECHANISM Filed April 30, 1963 2 Sheets-Sheet 2 ----NEUTRAL -BREAKOUT United States Patent 0 3,187,913 IMPLEMENT POSITION (IUNTROL MECHANISM Don S. Strader, Mount Prospect, and Robert G. Lutt, Wildwood, IlL, assignors to The Frank G. Hough Co.,

a corporation of Illinois Filed Apr. 36, 1963, Ser. No. 276,913 4 Claims. (Cl. 2I4-I4il) This invention relates generally to tool or implement control mechanisms wherein a tool is operatively carried from a vehicle and is movable through a certain range under control of the operator of the vehicle, and more particularly to a novel arrangement providing automatic indexing of the tool in some predetermined position intermediate the range of movement of the tool; In the present embodiment of the invention the novel automatic indexing arrangement is applied to a front-end-type tractor loader.

The primary object of the present invention is to provide a novel arrangement for accurately and positively indexing a vehicle-carried movable tool in some predetermined postion intermediate the range of movement of the tool.

It is a further object to provide a novel arrangement for accurately and positively indexing the bucket of a frontend-type tractor loader in a predetermined position.

It is a further object to provide novel indexing means for a hydraulically-operated front-end-type tractor loader which will operate in cooperation with thebucket-tilting means thereof to provide automatic indexing of the bucket in a predetermined tilted position.

It is still another object to provide a novel construction in arrangements of the preceding paragraphs so that the automaticindexing function may be easily and manually overridden. 1

It is a further object toprovide a novel indexing arrangement for the bucket'of a front-end-type tractor loader which will automatically operate when the bucket is being pivoted from a dump position toward a digging position to stop the bucket in a predetermined digging position.

It is a further object to provide a novel tool-indexing arrangement which can easily be applied to and incorporated in the hydraulic circuit means of existingtypes of vehicle-carried hydraulically-movable tools, to provide automatic indexing of the tool in a predetermined position.

Other objects and features of the invention will be ap parent upon a perusal of the following specification and drawings, in which:

FIGURE 1 is a side elevational view of a front-end-type tractor loader constructed according to the present invention;

FIGURE 2 is an enlarged partial view of the indicator means of FIGURE 1 for indicating the pivoted position of the bucket shown in FIGURE 1;

FIGURE 3 is an enlarged end view of the shown in FIGURE 2;

FIGURE 4 is an enlarged partial view of a portion structure of the structure in FIGURE 2;

FIGURE 5 is an enlarged side elevational view of the valve arrangement of FIGURE 1 with the hydraulic apparatus connected thereto being shown in reduced scale and substantially diagrammatical;

FIGURE 6 is an enlarged side view of a portion of the structure shown in FIGURE 5;

FIGURE 7 is a diagrammatic view of a portion of the hydraulic circuits of the invention; and

FIGURE 8 is an electric circuit diagram of a portion of the invention. L

The present embodiment is the preferred embodiment, but it is to be understood that changes can be made in the present embodiment by one skilled in the art without departing from the spirit and scope of the present invention.

Patented June 8, 1965 Generally, the novel indexing means in the present embodiment of the invention is applied to a front-endtype tractor loader and is partially carried on the tractor and partially carried on the bucket-tilting assembly thereof. The bucket-tilting assembly of the tractor loader includes a double-acting hydraulic cylinder, one end of which is pivotally carried on the tractor, and the other end of which is connected to the bucket by a linkage and leverage arrangement. The double-acting hydraulic cylinder is selectively extended or retracted to pivot the bucket relative to the boom. In the present embodiment, an extension of the. hydraulic cylinder causes the bucket to be pivoted rearwardly to what is commonly called'the breakout position. A substantially complete retraction of the hydraulic cylinder will cause the bucket to be pivoted to a dump position. The digging position of the bucket is intermediate the breakout and dump positions.

The bucket hydraulic cylinder is selectively extended and retracted by means of a manually operated hydraulic control valve carried in the operators compartment of the tractor. The hydraulic control valve comprises a valve body having a bucket valve spool slidably carried therein for longitudinally reciprocating movement. The control valve may include a spool for controlling the operation of the cylinder-for raising and lowering the boom; however, since the boom hydraulic circuit forms no part of the present invention, any showing or description relative thereto may be omitted.

The bucket valve spool is manually reciprocated by a hand lever assembly connected thereto. Each end of the hydraulic cylinder for tilting the bucket is connected by suitable conduits into the valve bore for the bucket spool. A source of hydraulic fluid pressure and a reservoir are also connected to the control valve. It is contemplated in the present invention that the control valve be of the type commonly known as an open-center valve. In such a valve, the bucket valve spool is normally spring-biased to a center neutral position. In the center neutral position, both ends of the buckethydraulic cylinder are blocked and the source of hydraulic fluidpressure is connected to the reservoir conduit. Moving the hand lever to move the bucket spool in one direction from the center neutral position will cause the source of hydraulic fluid pressure to be connected to one end of the hydraulic cylinder while the other end of the hydraulic cylinder is connected to the reservoir. Manual movement of the hand lever to move the bucket spool in the opposite direction from the center neutral position will cause a reversal of the connections of the source of hydraulic fluid pressure and the reservoir to the hydraulic cylinder. Thus it may be seen that when the operator of the tractor loader moves the bucket spool hand lever in one direction, the bucket ispivoted in one direction, and when the operator moves that hand lever in the opposite direction, the bucket is pivoted in the opposite direction. When the hand lever is released, the bucket is stopped in whatever pivoted position it had attained prior to release of the hand lever.

In the present embodiment of the invention, the extending end of the bucket spool, which is connected to the hand lever by means of a link and lever assembly, is provided with a detent plate on a pair of links connecting the extending end of'the bucket spool to a lever on the hand lever assembly A spring-biased and air-retracted pawl assembly is carried in cooperation with the detent plate so that when the handlever is pivoted to move the bucket spool to the operated position thereof for pivoting of the bucket toward the breakout position, the tip of the spring-biased and air-retracted pawl assembly will engage a notch in the detent plate to hold the bucket spool and the hand lever assembly in that operated position, thereby enabling the operator to release the hand lever. When the spring-biased pawl is holding the bucket spool, the

sass/p13 holding force exerted thereby is suflicient to overcome any force of the bucket spool biasing means tending to return the bucket spool to the center neutral position. Theanotchdn'the detent plate which 'is' engaged by the spring biased pawl is so shaped that when the tractor operator manually'atternpts to return the bucket spool to the center neutral position, the spring-biased pawl will slip fr'om the notch in the 'detent plate to "permit-the bucket spool to be manually returned to the center neutral positior 1.; Thus the holding function of thesp'ring-biase'd pawl and the detent plate is relatively "easily manually overridden. g

, When the hand lever is pivoted to move: the bucket spool between the center neutral position and the operated position thereof for pivoting of the buckettowa'rd the dump position, the'tip of the spring biased pawl will slide over the surface of the detent plate and any force exerted. by the spring-biased pawl on the detent plate will be in'suflicient to maintain the hand lever'asse'mbly and the bucket spool in the dilmp position so that if the hand lever assembly is released by the tractor operator when the bucket spool is in the du-mpposition, the springbiasing means for the bucket spool willreturn the bucket spool and the hand lever assembly to the center neutral position. I The three positions of the bucket spool are indicated in FIGURE 6 by the legends BREAKOUT, NEUTRAL, and DUMP. The spring-biased and air-retracted pawl assembly in the present embodiment comprises a small air cylinder with the pawl being defined by the tip, of the piston rod of the air cylinder. A compressed coiled spring is carried between the head end of the air cylinder and piston head to bias the piston rod to an extended position. ,An air conduit is connected to the rod end of the air cylinder to pr'ovidefor retraction of the piston rod against the bias of the coiled spring responsive to the application of air under pressure to the conduit.

The above described arrangement is combined with certain indicator means for controlling the application of air under pressure to the" spring-biased and air-retracted pawl assembly to release the bucket spool and hand lever assembly when the bu termined pivoted position. Thespecific indicator means used in the present embodiment is byway of example only as many other types of indicator means may be used to control the application'of air under pressure to the springbiased'and' air-retracted pawl assembly. In the present embodiment the indicator means comprises a pointer movable over a scale, and the pointer is moved in response to extensions and retractions of the bucket tilting cylinder. cylinder are used in the 'pressent embodimentrbecausethe various pivoted positions of the bucket are a direct function of the various extended and retractedpositions' of the bucket'cylinder. When'the pointer of the indicator means indicates a certainipi'edetermined pivoted position of the bucket on the scale, suchas the digging position shown in FIGURE 1, an electric switch is operated by thefpointer'atthat position. When the electric switch is operated by the pointer, a circuit is completed for operation of a solenoid-operated air valve. When the solenoidoper'ated' air valveis operated, a source of air under pressfieisconnectedito"the spring biased and air retracted pawl assemblytocause' itsretractioii. Thus it may be seen that'when, in response to initial movement of hand lever 'a's's'eniblytothe breakout position, the bucket reaches the digging position in m oving from the dump position toward the breakout position, the spring-biased and airretracted pawl i s retracted from the notch i the detent plate tofpermit the bucket spool to be returnedto the center neutr al positionunder the influence of the springbiasing of the bucket spool. When the bucket spool returns to the center neutral position, the bucket cylinder is stopped, and the bucket is indexed in the digging posinon.

'cket has attained a certain prede The extensions and retractions of the bucket The present invention also contemplates that the spring biased and air-retracted assembly may be retracted by a fluid other than air. For example, a suitable hydraulic fluid arrangementmay be used. c r a The present invention, finds particular application to vehicle-carried movable tools .or implements wherein by virtue of the distance orposition of 11151001 relativeto the operator of the vehicle the accurate-positioning of the tool or implement insome position intermediate the range of movement of the tool is diificult. This condition commonly occurs in the art-offront-end type tractor loaders wherein due to the size of the tractor loader and the location-of the operator relative to the cutting edge of the bucket,- it is very.;-difficultto adjust the pivoted position of. thebucket to achieve an accurate ground-level digging position. ;When applied-to afrontend type ,tractor loader, the present invention; substantially increases the efiiciency. of :the tractor loader by freeing the operator of the tractor loader from the necessity of repeatedly attempting toposition-t-he bucket in the digging position. In the I customary front-endtype trace tor loader, the work cycle of digging a load,; tilting the bucket to the breakout position, raising,theboom to a position for convenient carryingof the bu,cket, carrying the loaded bucket to-a positionv fondumping generally further raising the boom for dumping of the loaded bucket onto a pile. or into a truck, pivoting the bucket to .the dump position todeposit the load, lowering the-boom and pivoting the bucket from thev dump position tothe dig ging position, is constantly repeated. The present invention results in a substantial reductiondnwork cycle time by permitting the operator of theiloader to move the hand lever of the bucket'controbyalye to the position for pivoting of the bucketfronpthe dumppositionto- Ward the digging position, and While the bucket is1pivoting toward the diggingv position without any further attention from theroperator,the operator mayconcentrateon lowering the boom and returningthe, tractor to the digging area.- The -procedure,enablestheoperator to move more rapidly and effectively to control the tractor loader to substantially shorten the work cycle time. Further, because the operators position rearwardly and above the bucket is removed asubstantial distance-from the cutting edge of the bucket, it is,oftentimes diflicult It will be apparent from the hereinafter. following de tailed description of the ,pres ent embodimentof the invention. that the invention may be,,used toindex the bucket in pivoted positions other thanthe digging posi tion, or that some tool'or-implementotherfithana digging bucket may be indexed in;s on1e particular position, or that the invention might also be applied to, the hydraulic cylinder assembly for raising and loweringthe boom to provide for automatic indexing of the boom in some predetermined position. i g

In detail, one type of tractorloader is shown in side elevation in FIGURE 1 with the boom in alowered position and with the bucket in the digging position. The tractor comprises av frame. 10 supported, ,on' .rearward wheels 11 and forward wheels '12. An, opjeratorfs compartment 13 is carried on the frame 10 forwardly of an engine compartmentld' 1 Y The loader comprisesya boom: assembly AS iWhich is pivotally connected at the. rearward end thereof to the tractor by a pin means 16. The'other end of the boom assembly 15 extends forwardly of the tractor. The forward end of the boom assembly 15 is raised and lowered by hydraulic cylinder means, such as hydraulic cylinder 17. The head end of the hydraulic cylinder 17 is pivotally connected to a bracket 18 by a pin 19. The bracket 18 is secured to the frame 14) of the tractor to depend therefrom. The rod end of the hydraulic cylinder 17 is pivotally connected to the boom assembly intermediate the ends thereof by a pin 20. g y i A digging bucket 21 having a cutting edge 22 carried on the forward marginal edge of the bottom wall thereof is pivotally carried on the forward end of the boom assembly 15. Flanges, such as flange 23, secured to the rearward side of the bucket 21 are provided for the pivotal connection of the bucket 21 to the boom assembly 15. A pin assembly 24 is journaled through the flange 23 and the forward end of the boom assembly 15.

The pivotal position of the bucket 21 relative to the boom assembly 15 is determined by bucket-tilting means comprising a hydraulic cylinder 25, a lever assembly 26 and a link assembly 27. The head end of the hydraulic cylinder 25 is pivotally connected to :a bracket 23 by a pin 30. The bracket 28 is carried on the forward end of the tractor substantially at the transverse center thereof. The rod end of the hydraulic cylinder is pivotally connected to one end of the lever assembly 26 by a pin assembly 31. The lever assembly 26 is pivotally carried intermediate the ends thereof on the boom assembly 15 intermediate the ends thereof bya pin assembly 32. The other end of the lever assembly 26 is pivotalpin assembly 33. The other end of the link assembly 27 is pivotally connected to the flanges 23 on the rear wall of the bucket by a pin assembly 34. The various described members of the bucket-tilting means are relatively sized and positioned so that when the hydraulic cylinder 25 is partially extended and the boom is substantially lowered as shown in FIGURE 1, the lever assembly 26 is positioned in a substantially vertical direction and the bucket 21 is positioned in the ground level digging position. When the hydraulic cylinder 25 is substantially completely extended, the bucket 21 is pivoted rearwardly about theaxis of the pin assembly 24 to the breakout position. When the hydraulic cylinder 25 is substantially retracted, the bucket is pivoted forwardly to the dump position.

A main control valve 36, shown in FIGURES 1 and 5, is provided for selective operation of the hydraulic cylinder 25 by the operator of the tractor loader. Although not shown in the drawings, the main control valve 36 may also include valve means for selective operation of the hydraulic cylinder 17 by the operator of the tractor loadern The main control valve 36 is carried in the operators compartment 13 at a convenient location therein for manual operation. FIGURE 5 shows the connection of the hydraulic cylinder 25 to the main control valve 36. The main control valve 36 comprises a bucket spool 37 carried in a valve borefor longitudinal reciprocating movement therein. The upper end of the bucket spool 37 extends outwardly of the body of the valve 35. The other or lower end of the bucket spool 37 is provided'with a biasing assembly 38 forbiasing the bucket spool 37 to a center neutral position. The'biasing assembly 38 permits the bucket spool 37 to be moved in either direction from the centerneutral position to different operated positions; The different operated positions in each direction from the center neutral position are indicated in FIGURE 6 by the legends BREAKOUT and DUMP on either side of the legend NEUTRAL for the center neutral position. The biasing assembly 38 is shown in cross section in FIGURE 5, and may be seen to comprise a pair of washers 40 disposed about a reduced section of the bucket spool 37 with a compressed coil spring 41 carried between the'washers 40. In FIG- URES 5 and 6, the bucket spool 37 is shown in the center neutral position, and it may be seen that if the extending end of the bucket spool 37 is moved either down- 1y connected to one end of the link assembly 27 by a i wardly or upwardly, one of the washers 45 will be moved off of its seat in the housing of the assembly 38 by the abutting portion of the bucket spool 37 to further compress the coiled spring 41. If the upper extending end of the bucket spool 37 is moved downwardly, the upper washer will be unseated, and if the upper extending end of the bucket spool 37 is moved upwardly from the center neutral position, the lower washer 49 will be unseated. It may be seen that if the bucket spool 37 is free to move from one of the operated positions, the compressed coiled spring 41 will, in reacting against the seated washer 40, apply a force to the other washer 40 and in turn to the bucketspool 37 to return the bucket spool 37 to the center neutral position. The specific described arrangement 33 for biasing the bucket spool 37 to the center neutral position is by way of example only, and it should be understood that many other types of selfcentering arrangements may be used for the bucket spool 37.

A hydraulic fluid pump 42, capable of supplying sufficient hydraulic fluid under pressure for operation of the hydraulic cylinder 25, is provided, and the pressure side of the pump 42 is connected to one end of the conduit 43. The otherend of the conduit 43 is connected into the valve 35. The suction side of the pump 42 is connected by a conduit 44 to a hydraulic fluid reservoir 45. The hydraulic fluid reservoir 45 is also connected to the valve 36 by a return hydraulic fluid conduit 46. The bucket spool 37 and the valve bore carrying the bucket spool 37 are provided with suitable lands and grooves (not shown), cooperating with the connections of the hydraulic cylinder 25 and the connections of the con duits 43 and 45 to the valve 36 so that when the bucket spool 37 is positioned in the center neutral position, the conduits to the hydraulic cylinder 25 are blocked, and

. conduit 43 is connected through the valve bore to conduit 46. The lands and grooves are further so formed thatwhen the upper extending end of the bucket spool 37 is moved upwardly from its center neutral position, conduits 43 and 46 are connected to the conduits of the hydraulic cylinder 25 so that hydraulic fluid under pressure is delivered to the rod end of the hydraulic cylinder 25 while the head end thereof is connected to the reservoir 4-5 to cause a retraction of the hydraulic cylinder 25and a consequent pivoting of the bucket 21 toward the dump position. The described lands and grooves are further formed so that when the upper extending end of the bucket spool 37 is moved downwardly from the center neutral position, hydraulic fluid under pressure is connected to the head end of the hydraulic cylinder 25 while the rod end thereof is connected to the reservoir 45 to cause an extension of the hydraulic cylinder 35 and a consequent pivoting of the bucket 21 toward the breakout position.

'The bucket spool 37 is manually movable against the bias of the coiled spring 41 by appropriate movement of a hand lever 48. The lower end of the hand lever 48 is secured to a sleeve 50 to extend radially outwardly therefrom. A lever arm 51 is also secured to the sleeve 50 to extend radially outwardly therefrom. The sleeve 50 is journaled on a horizontally extending pin 52. One end of the pin 52 is secured to the upper end of a bracket 53. The lower end of the bracket 53 is secured to the body of the valve 36 to upstand therefrom. The outer end of the lever arm 51 is pivotally connected between and to one end of a pair of links 54 by a pin 55. The pair of links 54 depends from the lever arm 51 and the lower end of the pair of links 54 is pivotally connected to the upwardly extending end of the bucket spool 37' by a pin 56. The hand lever 48 is arranged on the opposite. side of the sleeve 50 from the lever arm 51 so that when the hand lever 48 is moved downwardly from the center neutral position, the bucket spool 37 is moved upwardly therefrom, and when the hand lever 48 is raised from the center neutral position, the bucket spool 37 downwardly tothe' other operated position.

Themea'ns which cooperates with 'the'valve 36 and the various members connected thereto to provide for automatic indexing of the bucket 21 comprises 'a'detent plate angt'a spring-biasedland air retracted pawl assembly 60. The detent plate 58 is seeilred toon'el'ohgituflinat edge of the pair of depending links '54 sothat the detefit plate58 mhvesin'a generally vertical direction as the hand lever 48'is pivoted t'o'move the bucket spool '37 upis moved wardly" and downwardly from the center neutral position. Theldet'en't plate 58 is provided with a notch 58d. A

. The spring-biased and 'air retracted pawl assembly 6t compr'ises'a"moutiting'plate 61,":1 fitting'tiz', a small air cylinder 63;a'n' assembly of a piston head and a piston rod 65, a compressed coiled s rings], and aunt 6 8 for securing the entire assembly togetherj The rod end of the air cylinder 63 abuts one side of the fitting 62, and with'the fitting 62"is' secured to one side of the plate s1 by'the nut 68 threaded'on the fitting 62 on the other side of the plate 61. The assembly of the piston head 64 and the piston rod 65 is carried in the air cylinder efiwith the piston rod 65 extending through the fitting at, the plate 61 and the nut 68. The head end of the air cylinder 63 is open'to atmosphere. The compressed coiled spring 67 is carried inthe fair eiyliiider 63 between the head end thereof ans'tne iston head 64 to urge the piston fed as outwardly of the air cylinder 63. An ai'rconduit is'connectedto the fitting'62 and a passageway isprovided through the fitting 62 so that any air under pressure de livered to conduit 74 is directed into therod end of the air cylinder 63 to 'cause a retraction of thepist'on rod 65 against the bias of the coiled spring 67. The extending end of the piston rod 65 is spherically shaped to define apa'wlsurface which'ca'n cooperate with the notch 58a of the detent plate 58 to hold the" pair of links against movement. It is obvious that when the pair of links 54 is held against movement, the hand lever 48 and the bucket spool 37 are also held against movement. The mounting plate 61 of the spring-biased and air-retracted pawl assembly 60 is secured to the body of the valve 36 so that'the pawl surfaceor" the pistonlrod o'will slide'on the surface of the detent plate 58 when the hand lever es is moved to move the bucket spool 37 upwardly and downwardlyt The spring-biased" and i air-retracted pawl" assemnl'y 60 is further positioned relative to the detentplate 53 so that when the hand lever 48 is operated to move the bucket spool 37 downwardly to operated position thereof for pivoting of the bucket 21 rearwardly toward the break;- 'out position, the pawl surface of the piston rod 55 will engage the notch 58a of the detent plate 58. The pawl. surface of the piston red 65 is so'shaped relative to the notch 58a of the detentiplate 58 that thehand lever 48 may relatively easily be manually -rnoved downwardly to move the bucket spool 37 upwardly with the pawl surface of the piston rod 65 moving; out of the notchfisa This construe-hon provides an arrangement for relatively easily. m lhually overriding'the automatic indexing function of e -b a ed and a rt actedip w lasseiiib yMiam t d P a e 5 V .Althqush he d bed. autom ti indexing function maybe relatively easily manually oven. ridden, the holding arrangemeiit of the spring-biased and air-retracted pawras mbw 60 is such that when pawl surface of the pistonirod 65engag e s' the notch ssaer the detent plate 58 the biasing force of thebucket spool biasing arrangement38*canno: nioveihe'bucket spool 37 upwardly to pull the notch 58a away from the pawl surface of thepiston rod 65. From the foregoing, it may be seen'that the hand lever-S is movable to move the bucket spool 37 between the center neutral positiorLand the breakout position with pawl surface of the piston rod .65 merely sliding over the surface of detent plate 58. If

the hand lever 48 is released with the valve spool 37. in the.

operated position for pivoting of the u k 21 toward the dump position, the biasing force of the b k Spool area-ere pissing arrangement" 38; ill retain the were: span a? to the mater neutral position thereby; stopping I pivoting of thebucket Z1 toward the dump position to etiectively osiuen'me bucket121 in the tiltedfor pivoted position substantially attained when the hand [was re leased. Further, if the hand lever" :48 is movedfto move the bucket spool Bitfomfthe cen er neutral position to the osition for PiYoting the bucket '21 towardt he been out position, the p awl'surface of the piston rod 65 will engage the notch 58izfto'hold the bucket spears? in that operated position, thereby enabling t e p rsmr' to release hand lever 48 without a co'nseqentjreturn of the bucket spool37 to the center neutralposition. l

i To release the pawl surface of the piste". JrodldS from the notch 58a'of the :detent plate 58 and'lthe reby permit the biasing arrangement 38to return "to thebueket spool 37 to the center neutral position, 'a isolenoid operated air valve 72 is provided. The solenoid operatedaiivalve '72 is diagrammatically shown in FIGURE 7,' and 'as seen therein, the conduit '70 from thespring-biasedand airretracted pawl assembly/ 60 is connected to the'sole'iioidoperatedair.valve'72. An air pressure conduit 73 and an air exhaust conduit 74 are also connected to the" valve 72. The valve "72" is so constructed that, when thesolenoid thereof is energized, the valve isopera't'd to connect air pressure conduit 73to conduit 70, "and whenthe solenoid thereof is de ene'rgi zed, the air exhaust conduitf ll is corinected to conduit 7%). A source of air'u'nderfpressure 'for conduit 73 is" generally found in existing tractor loaders wherein compressed air is commonly used for operatioi'iv of the wheel brakes of the tractorl' A H The solenoid of the solenoid-operated'air valve 72 is momentarily operated in the present embodiment .by an electric switch 75 which is showniniFIG URES' 2, 3, and 8. One sideof the electric switch- 75 connected to. a source of power 76, which may be" the storagebattery" of the tractor; The other side of the oweqsouree 7s is grounded, as isone side of the solenoid of the solenoidoperated'air valve '72; ,The other side of'the solenoid is connected to the other side of electric switch 75;

Asshown in FIGURES l through 4,. thelswiteh 75'is carried in cooperation with a bucket position indicator mechanism indicated generally at 77 The speciiic bucket position indicator mechanism '77 shown in the drawings is by way of example onlyand many, other types of indicator systems maybe usedto operate switch 75. The bucket position indicator mechanism 77 comprises an arrangement which operates responsive to extensions and retractions of the bucket-tilting cylinderl2 5 to in dicate on a scale the various positions to which the bucket 21 is pivoted. This may be accomplished because the operatedlength of the bucket-tilting cylinder 25 is a direct function of the tilted position of the bucket 21.

The indicator mechanism 77 basically comprises three assemblies; a quadrant 78 and tube 89 assembly, an indicator arm 81 and rod 82 assembly, and a tube 33 assembly. v i Q N v x The assembly of the quadrant 78 andtube comprises;

the construction of the quadrant 78 as agenerally semi circular plate having a scaieon the side thereof toward. theoperators compartment 13. Ihe tubularmernberfiti is securedto the lower marginal edgeof the quadrant 78 at the center thereof with the tube 8t extending perpendicular to the plane of the quadrant 78. A flange 85. is secured to the tube 80 to extend radially therefrom at the end thereof 'whichjis secured tothe quadrant 78. Theouter end of the flange 85 ijs piv otally carried on the axis of pin; 30 which pivotally conne'cts the head end of the bucket cylinder 25 to the bracket 28 on the tractor, This arrangement permits the tube 80 to extend parallel to the longitudinal axis of the bucket cylinder 25 and toward the rod endthereof.

The assembly of the indicator armjdll and rod prises a circular plate 86 to which the indicator arm 81 is secured to extend radially therefrom. The circular plate 86 is secured to one end of a bushing and sleeve arrangement 87. The bushing and sleeve arrangement 87 is rotatively carried in the end of the tube 80 which is secured to the quadrant '78 so that the indicator arm 81 will sweep over the scale on the quadrant 78 when the bushing and sleeve arrangement 87 is rotated. The bushing and sleeve arrangement 87 is held against any lengthwise movement relative to the tube 80. The rod 82 is carried in the tube 88 and one end of the rod 82 is secured in the inner end of the sleeve portion of the bushing and sleeve arrangement 87. The rod 82 is twisted about its longitudinal axis as may be seen in FIGURES 2 and 4. From the foregoing it may be seen that if the rod 82 is rotated about its longitudinal axis, the indicator arm 81 will sweep over the scale on the quadrant 78 to indicate the rotated position of the rod 82.

The assembly of the tube 83 comprises a circular plate 88 which is secured over one end of the tube 83. The plate 88 is provided with a slot therethrough having a length and width substantially equal to the width and thickness of the rod 82. The rod 82 extends through the slot in the plate 88 and into tube 83. The end of the tube 83 opposite of the end having the plate 88 is provided with a flange 90. The flange 90 extends perpendicularly from the longitudinal axis of the tube 83 and at its outer end is pivotally carried on the axis of the pin 31 which pivotally connects the rod end of the bucket cylinder 25 to the upper end of the lever assembly 26. This arrangement permits the tube 83 to extend parallel to the longitudinal axis of the bucket cylinder 25 and into the tube 80 in a telescoping arrangement therewith. From the foregoing, it may be seen that as the bucket cylinder 25 is extended and retracted, the

tubes

80 and 83 are similarly extended and retracted, and as the

tubes

80 and 83 slide longitudinally of each other, the slot in the plate 88 of the tube 83 will cause rod 82 to be twisted about its longitudinal axis to in turn cause the indicator arm 81 to sweep across the face of the scale of the quadrant 78.

The various assemblies of the indicator mechanism 77 are so sized and positioned that when the bucket cylinder 25 is extended to the position shown in FIGURE 1 with the bucket 21 in the digging position, the indicator arm 81 is disposed substantially vertically on the scale of the quadrant 78 to indicate that digging position of the bucket 21 to the operator of the tractor loader seated in the operators compartment 13. When the bucket cylinder 25 is substantially'completely extended to pivot the bucket 21 to the breakout position, the indicator arm 81 will indicate that bucket position on one end of the scale of the quadrant 78, and when the bucket cylinder 25 is substantially completely retracted, the indicator arm 81 will be moved to the other end of the scale to indicate the dumping position of the bucket.

The previously described electric switch 75 for operating valve 72 is carried on quadrant 78 with the operating mechanism of switch 75 positioned so that arm 81 engages switch 75 to close its contacts when arm 81 indicates the digging position of bucket 21 on the scale of quadrant 78. Because of the slight time delay in the operation of the various components of the present embodiment of the invention, switch 75 may be positioned on quadrant 78 to be engaged slightly before the exact indication of the digging position by arm 81 as it moves from the dump position.

Assuming bucket 21 to be at rest in its dump position,

spool 37 will be in its neutral position so as to direct fluid to reservoir 45 rather than bucket cylinder 25. In order to move bucket 21 away from its dump position, spool 21 is manually moved downwardly as shown in FIGURE 6. Detent plate 58 is carried downwardly with spool 37 until notch 58a is engaged by rod 65, at which time spool 37 directs fluid to bucket cylinder 25 so as to pivot bucket 21 from its dump position toward its breakout position.

Arm 81 indicates the movement of bucket 21. Upon engagement with switch 75 solenoid-operated air valve 72 is actuated so as to supply air to the rod end of cylinder 63, thus retracting rod 65 from engagement with notch 58a.

The biasing assembly 38 of spool 37 will then move spool 37 upwardly to the center neutral position, and extension of the bucket cylinder 25 will be stopped with bucket 21 accurately indexed in the digging position and with arm 81 indicating that position on the scale of quadrant 78. By. the time bucket cylinder 25 has stopped with bucket 21 indexed in the digging position, arm 81 will have passed over the operating mechanism of switch 75, and switch 75 will have restored to open its contacts thereby de-energizing the solenoid of air valve 72. Upon de-energization, the rod end of air cylinder 63 will be connected to exhaust, and spring 67 will again urge piston rod 65 outwardly with the pawl surface of piston rod 65 sliding over the surface of detent plate 58.

Having described the invention what is considered new and desired to be protected by Letters Patent is:

1. For use with a tractor having an implement movably carried thereby and a hydraulic system including a cylinder connected with said implement for moving same, valve means in said system connected withsaid cylinder and movable between a neutral position and first and second operating positions in which hydraulic fluid is directed to and from said cylinder for moving said implement respectively in first and second directions, spring means associated with said valve means for biasing same toward said neutral position, manually operable means connected with said valve means for moving same between said positions, said manually operable means including a detent notch movable in accordance with movement of said valve means, indexing means associated with said valve means and including pawl means engageable with said detent notch upon movement of said valve means to said first operating position for holding said valve means in said first operating position, said indexing means further including pneumatic means for disengaging said pawl means from said detent notch, and actuating means associated with said pneumatic means and responsive to movement of said implement in said first direction for actuating said pneumatic means when said implement reaches a predetermined point in the course of its movement in said first direction.

2. The invention according to claim 1, said pneumatic means being electrically actuatable, and said actuating means including an implement position indicator dial, an implement position indicator arm connected with said cylinder for movement in response to movement of said implement, and electrical means engageable by said arm in the course of its movement for actuating said pneumatic means.

3. The invention according to claim 2, said electrical means including a switch engageable by said arm, said switch and said arm being so constructed and arranged as to be disengaged upon movement of said valve means to said neutral position in response to actuation of said pneumatic means.

4. The invention according to claim 2, said indexing means further including spring means biasing said pawl means toward engagement with said detent notch, said spring means being of such strength that said manually operable means is capable of independently moving said valve means from said first operating position.

References Cited by the Examiner UNITED STATES PATENTS 1,970,998 8/34 Ferris 9l389 X 2,782,946 2/57 Hough 214- 2,853,200 9/58 Beyerstedt 214l40 3,045,845 7/62 Hackett et al. 214--l40 HUGO O. SCHULZ, Primary Examiner.

Claims

1. FOR USE WITH A TRACTOR HAVING AN IMPLEMENT MOVABLY CARRIED THEREBY AND A HYDRAULIC SYSTEM INCLUDING A CYLINDER CONNECTED WITH SAID IMPLEMENT FOR MOVING SAME, VALVE MEANS IN SAID SYSTEM CONNECTED WITH SAID CYLINDER AND MOVABLE BETWEEN A NEUTRAL POSITION AND FIRST AND SECOND OPERATING POSITIONS IN WHICH HYDRAULIC FLUID IS DIRECTED TO AND FROM SAID CYLINDER FOR MOVING SAID IMPLEMENT RESPECTIVELY IN FIRST AND SECOND DIRECTIONS, SPRING MEANS ASSOCIATED WITH SAID VALVE MEANS FOR BIASING SAME TOWARD SAID NEUTRAL POSITION, MANUALLY OPERABLE MEANS CONNECTED WITH SAID VALVE MEANS FOR MOVING SAME BETWEEN SAID POSITIONS, SAID MANUALLY OPERABLE MEANS INCLUDING A DETENT NOTCH MOVABLE IN ACCORDANCE WITH MOVEMENT OF SAID VALVE MEANS, INDEXING MEANS ASSOCIATED WITH SAID VALVE MEANS AND INCLUDING PAWL MEANS ENGAGEABLE WITH SAID DETENT NOTCH UPON MOVEMENT OF SAID VALVE MEANS TO SAID FIRST OPERATING POSITION FOR HOLDING SAID VALVE MEANS IN SAID FIRST OPERATING POSITION, SAID INDEXING MEANS FURTHER INCLUDING PNEUMATIC MEANS FOR DISENGAGING SAID PAWL MEANS FOR SAID DETENT NOTCH, AND ACTUATING MEANS ASSOCIATED WITH SAID PNEUMATIC MEANS AND RESPONSIVE TO MOVEMENT OF SAID IMPLEMENT IN SAID FIRST DIRECTION FOR ACTUATING SAID PNEUMATIC MEANS WHEN SAID IMPLEMENT REACHES A PREDETERMINED POINT IN THE COURSE OF ITS MOVEMENT IN SAID FIRST DIRECTION.