US2668631A

US2668631A - Hydraulic loader

Info

Publication number: US2668631A
Application number: US778221A
Authority: US
Inventors: Harley R Reese
Original assignee: REESE ENGINEERING Co
Current assignee: REESE ENGINEERING Co
Priority date: 1947-10-06
Filing date: 1947-10-06
Publication date: 1954-02-09
Anticipated expiration: 1971-02-09

Description

H. R. REESE HYDRAULIC LOADER Feb. 9, 1954 4 Sheets-Sheet 1 Filed Oct. 6, 1947 INVENTOR.

I HARLEY, R. REESE m 4 W A TTORNEVS F eb. 9, 1954 Filed Oct. 6, 1947 H. R. REESE HYDRAULIC LOADER 4 Sheets-Sheet 2 INVENTOR. HARLEY R. REESE A TTORNEYS Feb. 9, 1954 H. R. REESE 2,668,6

HYDRAULIC LOADER Filed Oct. 6, 1947 4 Sheets-Sheet 3 HARLEY R. REESE A 7' 5 Nar Feb. 9, 1954 H; R. REESE 2,668,631

' HYDRAULIC LOADER Filed Oct. 6, 1947 4 Sheets-Sheet 4 INVENTOR. HARLEY R. REESE 764% f WM A 7'TORNE Y5 Patented Feb. 9, 1954 UNITED STATES PATENT OFFICE HYDRAULIC LOADER Harley E. Reese fluntington Park, Califi, assignoi to Reese Engineering Company; Los Angcles, Califl, a company of California Applicationflctbbett, 19 4 71 Serial N4 778 22 1.

'2' Claims. 1.

invention relates generally to hydraulic loaders, and .more specifically contemplatestractor attachments adapted for control by the driver of the tractor in eifectingthe manipulationof a bucket, fork, blade or the like comprising part of the attachment for loading dirt, pipe, boxes or othermaterials, well as for leveling, filling, scraping andanalogous: utilities;

While many diiterent types of loader attachmerits-for tractors have" been devised, the present invention is concerned generally with. a structure which embodies essentially a frame mounted uponthe tractor chassis in combination with hydraulically' actuated lifting arms extending in front of the tractor for the pivotal support and elevation of a suitable tool, of which a bucket may be considered representative.- It is common practice in such devices to raise the bucket by a hydraulic ram but to utilize gravity to lower the same; The bucket. isheld inoperative relationship with respectto the lifrtingv'arms: by suit able latching mechanism which, upon being tripped, permits the. dumping of the load; It is not possible with such constructions to apply a downward" pressure upon the bucket when the unit is employed asascraper as in leveling or inback-filling operations A greater disadvantage and limitation upon utility, however, results'from the fact that the bucket can be maintained: in only twopredetermined positions relative to the lifting arms. Asa consequence the tilt or the bucket is progressively increased as the arms are raised. If the armsare movable to aheight con-- sidered essential for universal utility; the: tilt of the: work-containing element" is often excessive; and renders thedevice impractical for the load-- ing of many materials, such as pipe-for example.

A principal object of the present invention. is to provide a loaderattachment for tractorscomprising: a' frame structure for the pivotal: support above the tractor of load-lifting arms actuated hydraulically toswing a load-containing mem her in a vertical arc in front of the tractor, wherein the load-supporting= member is movable relative'tothe arms and controlled hydraulically independent of movement-of the arms to afford aninfinitenumber of angular adjustments, the respective-hydraulic controls for the lifting arms and bucket being. double acting so as to-compel movement of said elements ineither direction upontheir respective pivots, and' thereby enable the application of downward pressure-tothe work as when employing. the device as a scraper.

Another and highly important objecthereof is the provisionof a load-lifting arm and bucket- 2 control assemblies relatively operable to mainthe pre-adii-isted angular position of the bucketthroughout the rangeoi movementoi thelifting arms,- ,thus obviating inadvertent disturbance of the load regardless of the height to which it is elevated while permitting any degree of manually-actuated correction of the angle when required at any position of the lifting arms.

Another object is to provide a frame structurefor the: support of the lifting arms and associated mechanism comprising a rectangular frame adapted to completely encompass the tractor chassis, and including. upright frame memberssecu-red to the sides-of the tractora-ndextending above the tractcr body for the pivotal support of the lifting arms; combination with a transverse beam connecting the lower ends or the uprights beneath the tractor and secured to thepower plantof the tractor to-reintorce the positions of the uprights.

Another object is to provide an indicator adapted for disposition-adiacentthe controls for the tractor and loader attachment, whereby the operator may determineinstantly the angle of the bucket or other load-containing device regardless of the dispostion of the latter in the range of movement of the lifting arms and throughout the: range of its independentpivotal movement.

Still another object is the provision of a hydraulio system for actuating loader mechanism of the type- -hereinabcve alluded to; embodying a pump actuated directlyfrom the crankshaft ofthe tractor engine, and a fluidreservoir adia= cent relationship toassure greater pumpefficiency and uniiormzhydraulicpressure through out the system;

Another object is to provide a forkassembly adapted tobe substituted: for the bucket, comprising brackets: pivotally associated with the lifting. arms and angle-control mechanism, to which the tines of thefork are individually pivoted to permit greater flexibility in manipulation when.desired ,.in combination with means to P transmit both upward and downward pressure to the tines when occasion requires.

Generally speaking,v this invention contemplates an attachmei'it. for tractors which iscapa- Isle of controlling work-engagingmeans in a very simple andeliect'i've manner. The invention contemplates a rectangular open framestructure adapted to receive and be secured toa tractor chassis or body, the frame structure including.

upright side frame members terminating at about the level of the steeringwheel of' the tractor.-

Pivotally connected to the top of the upright frame members are downwardly bent lifting arms which extend forwardly and are pivotally connected to a bottom portion of a work-engaging means in front of the tractor. Power means for each bent lifting arm includes a normally horizontally disposed hydraulic cylinder means pivotally connected to an upright side member intermediate its ends and to the bent lifting arm at the rear vertex of the included angle formed.

by the bent arm. Selective positioning of the work-engaging means is controlled by two'sets of parallelogram linkage systems for each arm, the two sets including a forward linkage means comprising a link member extending parallel to a forward reach of a bent arm and pivotally connected to the work-engaging means at its forward end and to one end of a virtually right angle knee lever at its rear end. The knee lever is pivoted at the other end to the lifting arm adjacent the outer vertex of the angle formed by the bent arm and includes a leg portion extending virtually in prolongation of the forward reach of the lifting arms. The second set or rear parallelogram linkage system includes a link member pivotally connected to the knee or at the angle of the knee lever and to one end of a bell crank lever which is pivoted intermediate its ends to the axis about which the lifting arms are rotated. The bell crank lever includes a forwardly projecting portion which is pivotally connected at its end to upwardly directed power means for actuating the linkage means.

allelogram linkage systems permits lifting of the arms without changing the selected position of the work-engaging means with respect to a horizontal plane. The power mean for the linkage means and for the lifting arms are independently controlled. 7

Numerous other objects and salient features of the invention, as for example relative simplicity of construction, ease of operation, maximum strength and durability under all normal working conditions, and versatility in application of the unit to the loading requirement of numerous industries, will be apparent to those of skill in the art upon an examination of the following description read in the light of the accompanying drawings, inwhich:

Fig. l is a side elevation of a tractor attachment embodying my invention, illustrated as installed upon a conventional tractor, shown partially broken away;

Fig. 2 is a plan view of the tractor and the attachment hereof depicted in Fig. 1;

, Fig. 3 is a schematic diagram of the hydraulic system; v

Fig. 4 is an elevation of a fork assembly adapted to be substituted for the bucket in association with the lifting arms and angle-control mechanism, shown partially broken away;

Fig. 5 is a reduced plan View of the fork assembly illustrated in Fig. 4, with the upper pivoted elements broken away to show, fragmentarily, the lower attachment for the tines;

Fig. 6 is. a perspective view of the loader frame assembly for supporting the lifting arms and control levers, the latter elements being broken away;

Figs. '7, 8 and 9 are sectional views, taken on correspondingly-numbered lines of Fig. 1, show ing, respectively, the connection between one of the rams, and the lifting. arm actuated thereby, the pivotal connection between one of the The particular arrangement of the two sets of par frame side plate.

lifting arms and the bucket, and the connection between one pair of control links and the bucket.

Referring to the drawings more in detail, the numerals of which indicate similar parts throughout the several views, I!) designates generally atractor upon which the loader attachrnent of my invention is mounted. The attachment comprises a rectangular yoke consisting essentially of a pair of uprights H adapted for attachrnent to the sides of the tractor as hereinafter more specifically described, and extending to horizontally-aligned points above the body of the tractor. A tubular member I2 is interposed between'the upper ends of uprights II and a transverse beam I3 extends beneath the tractor and is secured rigidly to the lower extremities of the uprights. Each of uprights II comprises a pair of identical sideplates I4 which are held in spaced parallel relationship by a plurality of transverse spacers I5 welded or otherwise secured rigidly to and extending between corresponding edge portions of plates Ia. Each upright is secured to a side of the tractor by a bracket comprising an inwardly-directed retainer plate H5 welded or otherwise secured to the forward edge of the inner side plate M thereof and disposed in a vertical plane. Forming a part of the same attaching bracket is a transversely arranged retainer plate I! welded vertically across the end of a horizontal member I8 similarly secured to the upright for the positioning of the latter plate ll inwardly from the inner face of the adjacent Each of the retainer plates I6 and H connected to each upright II are provided with a series of bolt holes to facilitate the attachment of the upright to the chassis of tracwith a series of holes for attachment of the composite beam I3 to the clutch housing or other suitable mounting of the tractor proper. It will be understood that the beam I3 supplants the usual fitting employed in conventional tractors for support of the rearward ends of forwardly diverging radius rods I9, numeral 20 indicating a hole in the center of the cross beam I3 for this purpose. The tubular member I2 comprising the upper transverse element of the yoke is welded to the inner side plates IQ of the respective uprights I I and houses bearings (not shown in opposite ends for the journalling of a shaft 2 I, the ends of which project through the respective upright frames II and terminate in the outer side plates I4 thereof. 22 indicates each of a series of pads welded to the opposing surfaces of the inner side plates I4 and to the outer surfaces of the outer side plates to reinforce the upper ends of these members.

The vertical disposition of the yoke is reinforced by a pair of braces 23 attached to the upper ends of the respective uprights II and extending downwardly and forwardly to the front of the tractor. The lower ends of braces 23 are each equipped with an'integral foot as to facilitate their attachment by bolts or the like to the tractor chassis.

, At the forward end Of'tl 'lfi tractor a bumper tank guard 25 is mounted which encloses and shields a reservoir tank 28 for the hydraulic sysaeoe ese tom. Atpump 21? of conventional: construction is lbcatotf within the loumper tank guazrdi 2211 adjoining: the reservoir for: direct connection-41:0; and actuationby; the cremlcshait- (not shown) of the tractor" engine. While a feature of the. in.- vention' resides in the close juxtaposition ofvpump 2! and reservoir 26: of the hydraulic system to one another and in: the location of; the pump. to receive motivation directivfiom: thea-ci ank shatt of'the engine; the precise design and constructionof these elements forms-inc part: of 'izhea presentiinvontion and accordingly arenot illustnated in detaili Thet'ank griardflii is reinforced by. a pair of diagonai braces secured to the upper end of the'guartf at opposite sides: of the tractor and at their lower ends to the respective braces 23' adjacent the connection of the latter to the chassis:

A pairof' lifting arms 29*, angular in form; are pivoted upon opposite end'sof -s'ha ft- '21. Each arm: 29 comprises a pair of side bars 30 secured rigidlyin parallel; spaced: relationship by' plates 31 extending across: the upper amllower edges, respectively; of the barsof the respective arms; Thep'ivoted: ends ofbars of each lifting arm are reinforced by pads 32, welded or otherwise secured therct'o, and are both arranged between the side plates. l t-of the upright frame H: with which the arm-is associated. Each arm 28 comprises two straight reaches forming obtuse angleitherebetween, withthevertexof the angle located oppositethetank guard 25 and the forward end of the armextending sharply downward: It will thus be seen! that this form of liftingarm locates the forward arcuately moving ends thereof closely adjacent the front endof thetractor when-the arms are in their lowermost position, the angle of the arms assuring ample clearance'for' the chassis of the tractor.

The outer end of the load-lifting arms 29 are connected p ivotally to a worm-engaging element which in the embodiment of Fig; 1 comprises a bucket 33 largely of conventional design and contour; The back and bottom of the-bucket consist of a si gle plate'im; theforward, lower edge of whichis equipped with a wear plate 35 -ex tendingthe-length of the bucket. Theend memhers 36of the bucket aresimiiarly provided with wearplates 35 at their leading edges towithstand the-firree of impact of these edges against the work; The outer suri-aoeof the and bottom plate 34. is reinforced by a pair of straps 3G; welded: or otherwise attached there-to at opposited-sides:of'the'middle or the-bucket (Fi 2%, to-each: of whichstraps 3 1 areattached' a pair of lugs 38 locatedadjacent the'bo-ttomof the buoket and extending rearwardly in parallel relation; The top and bottom plates 31 of the respective lifting arms 29 terminate short of the outer ends of the latter which are equipped" with pads 3'9 to reinforce the side bars 3*3- of the arms; As indicated in-Fig. 8, the reinforced ends-of the side bars 30 of' the respective arms encompass the lugsifi adja-cent corresponding ends ofthebucket and are journallecl tot-he lugs-by a pinwhereby the bucket maybe tilted freely withrespect to=the lifting arms;

The lifting arms are raised and lowered so as to impart corresponding movement to bucket 33 by hydraulic rams comprising a" pairof normally horizontallydisposed cylinders 41 pivotally mounted upon pins 4'2 in the respective upright frames l-l= of the yoke; The ends of pinsH-are carried: by the side plates I4" of" the frame in which they are disposed; respectively, so as to permit the H; to pron ect: toward. ward end of the tractor-end swing: in. vertical arcs; between the, spacers l-li? oi? the: sideeinames H. The, end of? each piston: rod 43?,[1110ifi33ti13 from the swinging: end; of each, ram is; equipped with. a pair of reinforcing plates: fll fiorming: a yoke: adapted to encompass a gusset plate: 45 welded, to the bottoms-l ofi the oorrrplementai'y' arm 29 at. virtually the inner? vertex of.:' theme cluded angle, formedby: the: contigu us lower edges of the arm. The end of) each: 43.: is pivotally' connected: to the-gusset plate 415 as; by a suitable extending through. the yoke; and the plate 45. It will thus; be; seen; that. hitdrauiic pressure transmitted to the bores: of the piuoied ends: ofthe cylinders 41 compels the extension of the, piston rods 43 and. corresponding siesta,- tion. of: the lifting; arms Zara-11d bucket 33; while pressure transmitted to the opposite; ends: off. the oylinders; 4.1" acting upon thepoppositeside-or, the piston therein is; efiectiveto lower-"the Bucket 33 may he looked against movementzor shiftedto an infinite number-of. positions wiizharespect to theliftingarm-s 2 9. To thlS'16Hd,.I pro-- vide a pair ofbellcranks 45 pivoted on opposite ends of shaft 2.l'withinrthe uprightframes: and betweenithe side bars air-of the respective; lifting arms 29, iournalled; on the ends. of the: shaft at corresponding sides or the unit. (Dne end ofeaoh bell crank 45 is pivotally associated" with. the plunger rod 47 of" a hydraulic, mm by" which; the tilting of" the bucket isacontrolled'. The lowerends of the cylinders 48 of the bucketecontrol: rams are pivoted: on pins 49 mounted inttheinespecfive uprights l l= at points below'and pearwanily of the pivotal connection of the cylinders: 4d. Boil cranks are pivoted in unison in'sresponsezto hydraulio pressure transmitted to the. cylinders-48 ofthe buoket-controlrams, aswis herein-after more in, detail: described.

The; upper opposite: end of each: of heliimianks 4-5 ispivotallyengaged by' a pair ofi paralleilinks 5.9 which extend forwardly inparallel? relation,- ship with the, pivotedi reach: of the: lifting arm therebelow; The forward ends of the respective pairs of links 50 arepivoted on; a; hinge pin 5t, journalled;between a pair of" angular plates Slat the angle thereof and torminga composite-virtue allyright. angled knee lever; 'Iihe: complementarylower ends of: the lever plates: were in turn; pivotaily secured by a hinge pin 53 to thenlifting armzfi thereb'elow at the=outervertex of the angledefined by the latter; Itwill'rthus he, seen that actuation: of" the hydraulic rams t'l -4B- resulting "in the tilting of the bell cranks 4:6 oorrespondingly'moves: the knee lovers of the bucket: control assembly: through the lihlcs 50. Hinge pins- M transfixihgthe upper ends: of the lever plates 52 of the respective knee lever- 8'ssembli'es' provide-- pivotal mountingsfor, respectit/rely, two: pair of links EJ- which extend forweirdly in parallel rel'ati-onshipwiththe outerends of the-lifting arm's-"Z5 therebelbw for pivotalettaoinnent tothebuoket 332 To accommodated-he forward ends of links: 55; each strap 310i bucket has welded thereto a rearwardlgrproj'eoting lug 5li 'disposed adj acentthe-upper'edge of the bucket, through which a pin 51 and bushing project (see Fig. 99'. The endsof the two-links ESat-eaclrsidp of the unit are mount'ed upon theends ofthe pin blanSfileil-lg'thelllg 55' in alignment therewith andarereinfbroedhypads-$8: I

important ieatuie of construction and operation lies in the particulararrangementat each side of the unit or the links 55 lying parallel to forward and downwardly extending'reaches'of an arm 29, knee lever 52 which is pivotally connected to one end of links 55 and to arm 29 at the outer vertex of the angle formed by the angularly related reaches of arm 29, and the pivotal connec tions of the lifting arm 29 and links 55 to the bucket. The pivotal connections between these several elements form the four corners of a forward set of parallelogram linkage means.

A rear set of parallelogram linkage means is cooperable with the forward set and comprises the pivotal connections made by the pivoted rear end of each lifting arm 29 about a horizontal axis, the parallel spaced links 59 lying above and parallel to the rearwardly directed reaches of each arm, the bell crank lever pivoted about said horizontal axis and having one leg pivotally connected to the adjacent end of links 59 and the pivotal connection of the other end of links 58 to the knee or intermediate portion of knee lever It will be apparent that a common point of pivotal connection of the two parallelogram sets of link age means occurs at the pivotal connection of knee lever 52 to the lifting arm 29. The distances between corresponding pivotal connections of each parallelogram linkage means are virtually equal as implied from the use of the term parallelogram. As is hereinafter explained more in detail, this arrangement of the bucket control mechanism and. the lifting arms '29 obviate any disturbance of the preadjusted angular 'dispesi tion of the bucket, incident to the movement of the lifting arms.

The hydraulic system, by which hydraulic fluid under pressure is supplied to the respective rams ll-43 and ll l3 for actuating the lifting arm 29 and bucket control mechanism, includes a conventional valve 59, the construction and details of which, being well known in the art, are not specifically illustrated. Referring more particularly to Fig. 3, it will be observed that fluid from the reservoir tank 26 is drawn into the pump 21 directly associated therewith through conduit 50 and transmitted under pressure to the pressure chamber of th valve 59 through a conduit 6| Leading out of valve 59 are two

flexible hoses

62 and 63 connected, respectively, to opposite ends of the two hydraulic cylinders ii by which the lifting arms 29 are actuated. In a

similar manner tubes

64 and 55 connect valve 59 with the opposite ends, respectively, of the ram cylinders 48 by which the bucket control mechanism is actuated. A fifth conduit 65 leading out of the valve conveysthe return flow of the hydraulic fluid to the reservoir 25. Valve 58 is actuated through suitable linkage by a pair of

manuallyoperated levers

61 and 68 mounted upon a suit- .able standard 55 adjacent the steering wheel "Hi of the tractor.

One lever 61 is effective for controlling the flow from the pressure chamber of valve 59 to the hydraulic rams M-43 for manipulating the lifting arms 29 while the other lever 68 controls the flow of fluid under pressure to the smaller rams 47-48 by which the bucket control mechanism is actuated. More specifically, the valve 59 is constructed to communicate the hose '52 with the pressure chamber thereof and coincidentally open the hose 63 with the return conduit 55 to the reservoir tank when the lever 6'! is drawn toward the operator so as to extend the rams l 43 and elevate arms 29 and bucket 33. Shifting lever 61 in the opposite direction opens the valve pressure chamber to the hose 63 leading .to the opposite ends of the respective ram cylinders 4| and communicates the hose 62 with the reservoir tank 26. A neutral or intermediate po-. sition for lever 61 is effective to close both

hoses

52 and 53 so as to maintain the preadjusted position of the ram pistons and accordingly locks the lifting arms 29 aganist movement. The other lever '68, similarly operated, permits the communication of tube 64 with the pressure chamber of valve 59 in response to its being drawn toward the operator and coincidentally communicates the opposite ends of the ram cylinders 48 with the reservoir tank 26 through tubes 65 and conduit 66 so as to compel the outward projection of the piston rods 41 and thereby tilt the bell cranks 46 rearwardly and the bucket 33 upwardly. Movement of lever 68 in the opposite direction vents the pivoted end of the ram cyline ders as to the reservoir tank 26 through tube 64- and return flow conduit 66 and transmits fluid pressure to the opposite ends of the rams through tube 65, thereby tilting the bucket downwardly.- As in the case of the valve control for rams 5 l43, an intermediate neutral position of lever '68 hydraulically locks the rams 4'!58 and control mechanism so as to maintain the adjusted position of bucket 33.

It will thus be. seen that the position of the bucket is controlled independently of the adjustment of the lifting arms 29. Accordingly, the bucket may be tilted to a position with its bottom vertically disposed and thereupon lowered against the work so as to permit the bucket to be employed as a back-filling scraper or leveling device. It will be appreciated, however, without specific illustration, that a conventional scraper equipped with lugs for its attachment to the ends of lifting arms 29 and links 55 may be substituted for the bucket if desired. The angle of the scraper with respect to the work may be altered in the same manner as is the bucket of the present embodiment, i. e., incident-to manipulation of the lever 88 through the control mechanism. The normal utility of the unit equipped with a bucket contemplates that the latter be initially positioned with its bottom in a horizontal position and disposed below the level of the work.

As hereinabove generally indicated, an important feature of the invention residesin the construction and arrangement of the control mechanism with respect to the lifting arms, whereby the position of the bucket relative to a horizontal plane and predetermined by adjustment of the control mechanism is maintained throughout the range of movement of the lifting arms. This result is achieved as a consequence of the compensating adjustment of the control mechanism effected by the knee levers 52 pivoted to the lifting arms 29. Thus elevation of the lifting arms tending to raise the back of the bucket and thereby tilt the latter forwardly also results in changing the angles between lifting arms 29 and the upward extensions of the bell cranks 46. However, as the links to are of a length equal to the distance between the shaft 2| for the arms 29 and the pivot axis of the knee levers 52, the latter will swing forwardly to an extent exactly proportionate to the elevation of the arms. Accordingly, the links 55 are projected forwardly relative to the lifting arms, without variation of the actual positions of the bell cranks 46, to a degree sufiicient to coincidentally and progrese sively compensate for the movement of the arms throughout the range of their movement.

It will thus be seen that the admission of hydraulic fluid under pressure into the ends of aceacci 9 the :ram cylinders H :pivoted to the "side frame uprights 'H (with the arms 29 and bucket, in the position shown in Fig. 1) -is-effective to initially induce-'motion-of the-bucket forwardly and slightly upward with the bottom of the bucket maintaining a 'preadjusted horizontal position, to .pick :up the :load. The bucket may be tilted backward slightlyas :arms 29 continue to rise so as to heap :the load inthe bucket-or prevent the some from falling out 'by the admission of fluid under spressure into the lower ends of the ram cylinders 48 associated with the bell cranks 46. Due to the .provision of dual controls, the tilting of. the bucket is entirely independent of the movement of arms 29, and accordingly an in- 1 the lever '6? to a neutra position, which results in closing both hoses e32 and 63 to both the return flow conduit t6 andthe pressure chamber of the valve mechanism as. Ther hOn bucket it may .be tilted to a degree required to eject the load. It w-ill be appreciatedthat while the dump ing of a load of dirt contained by the bucket may be accomplished quickly by the complete extension of the rams ii-48, the control mecha nism permits the gradual, controlled tilting of the bucket with a corresponding slow discharge of the contents thereof, or the bucket may be tilted to an extent only su fiicientto permit a load, comprising fragile goods, to be manually removed more readily.

When in its lower position, the bucket is not always entirely visible to the operator, i. a, when the arms 29 are in their lowermost positions. However, in order to facilitate the manipulation of the bucket throughout its range of operation, I provide an indicator disposed adjacent the tractor 'con'trols, whereby the operator lna'y ob- :serve at all times the exact angular position of the bucket or other load containing expedient with which the unit is equipped, with respect to a horizontal .plane. This device comprises an arcuate band ll having its ends rigidly secured to the rearward edge of the inner side plate |4 o'f one of the upright frames i l in horizontal alignment with the adjacent bell 'crank is. An indicator finger 12 secured 'to the hub of the bell =crank and-movable therewith is'be'nt to ev e'rhang band H which is marked in :a suitable manner :to indicate to the operator by the position *of the finger thereon, the angular disposition of the bottom of the bucket or corresponding or complementary element of a substituted loadcontaining member.

A modification of the load-containing member, comprising a sectional fork assembly is illus trated in Figs. 4 and 5. The device consists of a channel iron 13 and an angle 74 which are secured in horizontal, spaced, parallel relationship by a pair of vertical brackets IS, the upper ends of which are welded across the back of the channel 73 with the lower ends of the brackets 15 similarly secured to the angle i i. Brackets 75 are spaced apart a distance corresponding to the distance between the complementary lifting arms 29 which are pivoted as at 16 to rearward projections l? of the lower ends of the respective brackets. In a like manner the forward ends of the pairs of links 55 are pivoted by pins 58 to the upper ends of the respective brackets. Fitted into and welded to channel #3 are several forwardly projecting lugs 19, through which a rod 80 extendsyfor therpivotal-support of a plurality of tines 8L Each tine til consists-of --a bar bent to form a right angle, the sides &2 and -83 of which are of unequal length. The end of the shorterside fiz of each tine iii equipped with arpairof lugs s4 welded to the back thereof for pivotal association with the red 85. Encircling the rod'between the lugst i 'of-eachtine 3| is a tubular spacer and bearing E15 eiiective to reinforce 'lugs 8-5 which are slidable on the rod 80 so as to vary the .-juxtaposition of the tines -84 with respect, to one another. The longer side of each tine -83 iprojects forwardly for extension under the work, and to facilitate this result the forward ends of the tines are tapered as at -86, along their upper edges. Pivotal movement of the tines-3i on rod til is limited in-one direction by an angle ti secured rigidly across the back of angle 14; and by the 'latterangle itself. In order to maintain-the tines in their desired normal positions with respect to the brackets l5, I provide bumper pads 83 secured to the backs of the tines 8|, respectively, in positions to abut against the underside of the angle 8;! andag-ainst the back of angle l4. Theside of angled! which normally overhangs the bumper pads til-of the several times is provided with a series of holes 83 selectively registerable with holes formed in the respective pads 88, whereby insefi extending through such aligned complementary holes, are operable to retain the tines in fixed relationship with the brackets 15. The number of tines M carried by the rod 86 may accordingly be varied and their relative spacing altered within-limits determined by the number of holes -89 provided 'in angle 8 7. With the pins 90 engaged, the forwardly projecting elements 83 of the tines arosecured-inparallel relationship-and may be manipulated to assume di-fferentangles with -a-hori- .z ontal plane in the same manner as the bucket. Thus the tines may be raised and Jeweredby the lifting arms 29 and tilted forward or back according to requirements, by the control mechanism. -The compensating efiect of the control assembly whereby any .preadjusted angleof the load-containing member is maintained regardless of the movement of the lifting arms is particularly important in the utility of a fork attachment. In the loading of .pipe for example, the for'k may be inserted beneath the load with the forward-end of tineslll in'ahori-zontal plane and thereafter slightly tilted to avoid gravitation of the pipe from the fork. The load may then be lra'i'sedfquic'kly to the desired height by;merely transmitting the required power to the lifting arm assemblies and the fork will maintain its preadjusted position with respect to a horizontal plane without the necessity of progressive manipulation of the control mechanism.

Where the ground upon which the load is located is uneven, it may occasionally be difficult to initially place the tines beneath the load. By removing the pins 90, each of the tines may be permitted to float on the surface of the ground, the brackets being retracted somewhat incident to lowering of the arms 29 to enable the free movement of the tines on rod as they are advanced forwardly. Thus the forward tapered ends of the tines may follow the contour of the ground to a considerable degree in positioning them beneath the load. Tilting of the brackets 15 rearwardly in response to appropriate actuation of the control mechanism brings the

angles

14 and 81 into contact with the bumper pads 88 and thereafter correspondingly 1 l tilts the tines to pick up the load which may be supported and transported in the manner hereinabove described as if the pins 90 were engaged.

It will thus be seen that I have provided a tractor attachment comprising a frame structure embodying a yoke adapted to completely encompass the chassis of the tractor with the lower beam !3 thereof secured to the underside of the power plant of the tractor and the uprights I l on either side affording means for the pivotal support of angular lifting arms 29, and control linkage, and of hydraulic rams by which the latter elements may be actuated, the angular form of the lifting arms being effective to position the load-containing member closely adjacent the front of the tractor, in combination with control mechanism operable to hydraulically tilt the load-containing member to any of an infinite number of angular positions coincidentally recorded by an indicator adjacent the tractor controls, and further adapted to compensate for movement of the lifting arms so as to maintain the preadjusted angular disposition of the loadcontaining member throughout the range of movement of the lifting arms.

While I have shown and described but two embodiments of my invention, it will be .appreciated that various changes in size, design, number, shape and proportion of the various parts may be made, that other attachments such as a scraper equipped with means by which it may be connected to the lifting arms 29 and the control links 55 may be substituted for the bucket or fork, that conventional type fork assemblies modified as last above noted may be employed, and that an indicator may be included in the assembly similar to the indicator 1 [-12, for designating to the operator the positions of the lifting arms at all times, without departing from the spirit of my invention as defined in the appended claims.

What I claim and desire to secure by Letters Patent is:

1. In an attachment for a tractor, the combination of means including a rectangular frame structure for attachment to a tractor and providing a horizontal transverse axis intermediate ends of the tractor; a pair of forwardly and downwardly extending, angle-shaped lifting arms adapted to be disposed on opposite sides of the tractor, each lifting arm being pivoted at one end at said horizontal axis and pivotally connected at the front end to a work-engaging means; a pair of normally horizontally disposed hydraulically actuated means, each pivotally connected to said frame structure forwardly of the horizontal axis and pivotally connected to an associated arm in proximity to the inner vertex of the included angle formed in the angleshaped arm; means for controlling the position of said work-engaging means comprising a pair of forwardly facing knee levers, each pivotally connected at one end to an associated arm adjacent the outer vertex of the angle formed in the arm; a pair of front link means, each disposed parallel to a forward reach of an associated arm and pivotally connected at one end to said workengaging means and at the other end to the other end of the associated knee lever; a pair of bell crank levers, each pivotally connected intermediate its ends to the frame structure at the horizontal axis; a pair of rear link means, each disposed parallel to a rear reach of an arm and pivotally connected to the associated knee lever at the knee thereof and to one end of the associated bell crank lever; and a pair of hydraulically actuated means, each pivotally connected to the end of a forwardly extending leg of the associated bell crank lever and to said frame structure.

2. In an attachment as claimed in claim 1 including a work-positioning indicator means comprising a stationary curved member secured to the frame structure adjacent to said horizontal axis and to one of said bell crank levers and provided with indicia, and a cooperable indicator element carried by said one bell crank lever and movable therewith.

HARLEY R. REESE.

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