US2725995A - Front end loader with variable actuating arm - Google Patents

Description

Dec. 6, 1955 E. F. slLBAuGH FRONT END LOADER WITH VARIABLE ACTUATING ARM 2 Sheets-Sheet l Filed Jan. 2, 1955 Dec. 6, 1955 E. F. sxLBAUGH 2,725,995

FRONT END LOADER WITH VARIABLE ACTUATING ARM Filed Jan. 2, 1953 2 Sheets-Sheet 2 United States Patent Office FRONT END LOADER WITH VARIABLE ACTUATING ARM Elmer F. silbaugh, Humboldt, Iowa Application January 2, 1953, Serial No. 329,225

' s claims. (ci. 214-131) This invention relates generally to front end loaders and particularly to a front end loader with an automatically variable actuating lever arm.

In the design of front end loaders and the like it has been well known in the field that materially greater lifting force is required at the lower load elevations than at the upper. This is due to the longer horizontal load lever arm during the lower portion of the stroke as well as to the vexcessive force required to break the load loose at the bottom of the lifting stroke. It is also important that as much speed is produced in the lifting stroke as possible and particularly during the upper portion thereof where the lifting force required can be materially reduced. The uid capacity of hydraulic systems is also a critical consideration in the design of the hoisting mechanism for the front end loaders and, of course, the smaller the actuating rams, the smaller the reserve of fluid supply required and also the faster the possible elevating speed of the boom.

It is therefore an object of my present invention to provide a front end loader for farm tractors and the like which varies the applied lifting force with the requirements produced by the varying resisting force produced by` the load during the various portions of the lifting stroke.

It isafurther object to provide a front end loader having a lifting mechanism constructed to exert its maximumlifting force until the full boom extension position is obtained andy to progressively reduce the lifting force exerted on the boom as 'the same is elevated above its fully extended position.

It is another object to provide a front end loader having a lifting mechanism adapted to exert its lifting force on an actuating lever arm of maximum length during the lower portion of the lifting stroke and progressively shortening said actuating arm during the upper portion of said lifting stroke, permitting the maximum lifting force to be exerted during the lower portion of said stroke where it is required and increasing the elevating speed during the upper portion of the lifting stroke.

More specifically, it is an object to provide a front end loader having a pair of swingably mounted booms, each having a slideable connection intermediately mounted thereon for attachment of a hydraulically actuated lifting mechanism with link means attached to said sliding connections for shifting the same toward the respective pivot points of the booms to shorten the actuating lever arms of said booms as the same are raised above horizontal position, but constructed to maintain the maximum actuating arm during elevation to horizontal fully extended position.

These and other objects and advantages of my invention will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views and in which:

Fig. lis a side elevational view showing my new loader attachment with the scoop in lowered position by full lines and in progressively raised positions by dotted lines; Fig. 2 is a top plan view thereof; Fig. 3 is a fragmentary sectional view taken ksubstantially along the line 3 3 of Fig. 1; and

Fig. 4 is a fragmentary sectional view taken substantally along the line 4 4 of Fig. 1 and showing the attachment of the arm shortening link with the boom mounting member. l

As illustrated in the accompanying drawings, I provide a conventional farm tractor designated as an entirety by theV numeral 7 and having a pair of longitudinal frame members 8 disposed along the sides thereof in the usual manner. The tractor 7 isrprovided with a rear axle 9 on which rear wheels 10 are mounted. The front wheels 11, of course, steer the tractor and are mounted in a conventional manner.

The ease with which my loader can be mounted on the tractor is an important feature thereof. The pair of longitudinally disposed rigid mounting members 12 are adapted to be very easily attached to the tractor as best shown in Figs. l and 2. A forward mounting bracket 13 is rigidly fixed to the forward portion ofv each tractor frame member 8 as by the plurality of attachment bolts l 14 and each bracket 13 has a laterally outstanding attachment member 13a as best shown in Fig. 2. The forward end of each longitudinal mounting member 12 is securely anchored to outer portion of the respective laterally outstanding attachment members 13a as by a pair of U bolts 15 embracing the forward portions of each of'the mounting members 12. The rear ends of the two longitudinal mounting members 12 are securely anchored to the respective sides of the rear axle 9 as by the U bolts 16.

An upstanding boom supporting structure 17 is mounted in fixed relation on an intermediate portion of each of the mounting members 12 and the two upstanding mounting structures 17 as by the pivot pins 20. The forward end portions of the two boom members 19 are rigidly interconnected by the bracing structure 21 as shown in Fig. Zand a scoop member 22 is pivotally mounted on said forward boom portions in a conventional manner. In the form shown, the booms 19 are suitably reinforced by the overlying tie rods 19a asbest shown in Fig. 1. Y

The boom elevating mechanism consists in a pair of inclined hydraulic rams 23 having theirlowerrear end portions respectively pivoted to the lower portions of the upstanding structures 17 as best shown in Fig. l. A slidable sleeve 24 is shiftably mounted for longitudinal,` movement along intermediate portions of each of the, booms 19 as best shown in Figs. 1 and 2. A depending attachment web 24a is securely fixed to the lower portion of each of the sleeves 24. The upper forward ends ofthe rams 23 are respectively pivoted to intermediate portions of said attachment webs 24a asbest shown in Fig. 1. ment of the sleeves 24 along the booms 19 are provided such as the stop collars 25 which are respectively fixed to the booms 19 as by being welded thereto.

In order to provide the desired shifting movement ofA the sleeves 24 when the booms are swung upwardly beyond their horizontal fully extending position, an arm shortening link 26 is pivotally attached at its forward end to each of the webs 24a and the rear ends of said linkslv 26 arevrespectively pivotally connected to intermediate portions of the upstanding supporting structures 17 as by pivot pins 17a. spective supporting structure 17 and the rear end of the respective link 26 attached thereto, is made in the ,formr shown, by a clevis 27 having a guiding sleeve 27a rigidly attached thereto. It is'necessary that a limited amount of free extensibility of links 26 be provided Vbefore the same.

begin to pull downwardly and rearwardly on the sleeves Patented Dec. s, 1955` Suitable means for limiting the forward move-- This pivotal connection between ythe re- 3 24 to which.Y thesameare. connected since the actuating arms should not be shortened until after the booms 19 have been raised above horizontal position where, of course, the load is applied to the maximum horizontal lever. arm; In` the: formtshown', this'extensibilityl isfprovided by a lost motion connectiolrbetweenithe clevis- Z7 and= a: rod 26afslidably received throughthe guiding sleeve 27a and forming the rear 'endportionof link 2'6. Suitable stop means are; provided:` at; the rear endlof: each rodf 265.'

such as the: adjustable. nut 261i which' engages-the. outenV end: portion of. clevis 25T after.' the` rodv portion' 26a has moved a predetermined distance outwardly through the clevis. 2.7 and guidingsleevef27a. Until-.the stop` nut 25h actually-` movesL intor engagement with the endof the clevis:

27,` the` actuating armxof eachoftlie'hooms 19 will remain atA amaximum length andno' shorteningzthereofi will' take' place.' However, uponl engagement ofthe stop nuts` Zeb' the` arm: shortening links- 25 actually begintheir armv shortening: function, I have provided a vertical adjustment oftheclevis mounting pin 17'aat the rear of each of the links'26. This verticaladjustment is permitted by selectivelyinserting the pivot pin 17a in oneA ofv a plurality of holes 1-lb formed through each upstanding supporting structure 17l As bestr shown in Figs. 3and 4, each of` these upstanding structures 17v is constructed of a pair of spaced opstanding plates 17t` interconnected at their rear: edgesby a web plate 17d and the clevis 27f is interposed between saidtwo-plates with'the pin 17a extending through both plates and through the rear portion of the clevis asbest shown in Fig. 4. The adjustment of the elevation of pinsv 17a, ofcourse, varies the rate-at which the actuating arms of? the booms 19 are shortened by varying the relative pivot points of' the booms 19 and thelinks 26.

The following is a description of the` assembly and operation of my improved front and loader mechanism; The longitudinal mounting members 12l are securelyanchored to the tractor, as has been-previously'described;

bythe use of the U bolts 15,' which permit'the'space be- 1 tween the rear axl'e 9 of the tractor and the forward* attachment mounting brackets 13"to beeasily varied which', of course, greatly simplifies the attachment` of said lon'- gitudinal members 12. After said'members 12have been secured to the tractor, the booms` 19 are respectively mounted on-theupper portions of theupstanding support;- ing structures 1-7 and the ramsV 23` and links 26 respec= tively connected to the depending'websA 24U. 'Ihe rams 23 are connectedin the usuallmanner toa` conventional hydraulicspump (not shown) which may be a part'ofthe tractor equipment. by driving a tractor into thepile of material to bev elevated, and a large breaking'f'orce is applied to initially elevate the loaded scoop` from thev ground. The scoopV is thenelevatedlprogressively as shownby the'do'tted line.

positions of Fig; 1'. Thelostl motion connections respectively provided between the links 26 and the respective clevises 27 permits the sleeves 24 to remainV in forwardly projectedr position againstV the respective` stop' collars 25' until the boom has been elevated at least into'horizontalj Above this limit; tlierstopl nutsl fully extended position. 26b will engage the ends of clevises 27 andcause therespective sleeves 24 tobeshifted rearwardlyas'shown by the upper dotted positions of Fig; ltwherein. the sleevesY are spaced rearwardly from`thecoll'rs 25. This shorten- The scoop 22" is,` of course, filled'.

ing is, ofcourse, due to the spaced relation between the pivot points of the booms 19 andthe links 26 21nd,. as.

has been pointed out, this spaced relationship can be adjusted by varying the positions of the link pivot pins 17a.

It will be seen that I have provided a relatively simple yet highly eflicient front end loader with a controllably variable actuating lever arm which is progressively shortened after the load has beenv elevated above a predeterminedlimit to'permit not only faster elevation` ofi the load at the higher elevations thereof, but also to permit materially less fiuid to be required than is normally the case where the actuating lever arm remains constant throughout the entire elevating structuren on the boom.

It will, of course, be understood that various changes may be made inthe form, details: arrangement and proportions of the parts without departing from the scope of my invention, which generally stated, consists of the matter shown and described herein and set forth in the appended claims.

What-l claim is:

l. A hoisting mechanism comprising a supporting structure adapted to be mounted on awheeled'vehicle, a

forwardly extending boom pivotally mounted' at its rear` end on said supporting structure for swinging` movement onv a horizontal' transversely disposed axis, a ram'mountl ing member'slidably mounted on an intermediate portiony of said boom in forwardly spaced relation. to the pivotal axis of the boom, a hydraulic ram connected at its rear end to said supporting structure and extending generally forwardly therefrom and pivotally connected at its-forward end to said slidable mounting member, positive. stop` means connected to said boom and constructed to posi` tively limit the forward sliding movement ofthe mounting member, a shortening link connected at its forward end to said mounting member and its rear end to said. supporting structure in spaced relation below the pivotal. axis ofthe boom whereby the tensile force exerted by said link between said mounting and said. supporting stnucture when said boom is elevated by saidlramyvill. pull said slidable mountingmember rearwardly on said. boomto shorten the actuating lever armof the ram on the boom.

2. The structure set forth inV claim l and the rean end ofsaid ram being mounted a substantial distancebelow the pivotal axis of said boom, so that forcible extension of said ram willproduce elevationof said boom.

3. A hoisting mechanism comprisingl asupporting` structure, a boom pivotally mounted at its rear endfon` said` supporting structurefor. swinging movement on a horizontal axis disposed transversely of saidv boom, amounting member shiftably mounted on saidhoorn` in' forwardly spaced relation to the transverseA pivotal axisthereoffor back and forth movement longitudinally'of the boom, positive stop means xedto said4 boom stru tureand positivelyV limiting the forward shifting move ment of the-mounting member, lifting mechanism opera'- tively associated with said mounting member fox'. exerting."

liftingV force on` said boom, and a shortening linkl interconnecting` said mountingmember and. said supponlngj structure in4 a manner. to shift. said mounting memberl rearwardly on said; boomitoward the pivotall axis1thereofto'shorten the actuatingarm;thereof as the boom' is ele; vated` by said lifting` mechanism, said shortening link` having provision for limited initial extension to'permit` saidboom to be elevated. a predetermined distance before the actuatingarmA thereof is shortened by said link.

4. A front end loader for farmtractors and the like comprising a boom supporting structure adapted-tube mounted. in fixed relation on a farm tractor, a pair of transverselyspaced generally forwardlyextending substantially parallel booms pivotally mounted on.said supporting structure for swiging movement on a horizontal axis disposedtransverselyv of said booms, a-pair ofgenerally. forwardly extending. hydraulically. actuatedV boom.

lifting rams respectively connected at their rear ends to said boom mounting structures in spaced relation below the pivotal mountings of the two booms, a mounting slide mounted on each of said booms at apoint disposed in forwardly spaced relation to the pivotal mountings thereof and said mounting slides being respectively connected to the forward ends of said rams, a pair of generally forwardly extending shortening links respectively connecting said slides with portions of said boom mounting structure disposed in spaced relation below the pivotal mountings of the booms thereon whereby said mounting slides are respectively shifted toward the pivotal mountings of said booms as the same are elevated, and means rigidly interconnecting the forward portions of said booms to form a single hydraulically actuated boom structure.

5. A hoisting mechanism comprising a lsupporting structure adapted to be mounted on a wheeled vehicle, a boom pivotally mounted at its rear end on said sup- .porting structure for swinging movement on a horizontal transversely disposed axis, a mounting member' shiftably mounted on said boom in forwardly spaced relation to the pivotal mounting thereof for back and forth longitudinal shifting movement on said boom, means engaging said mounting member and positively the forward shifting movement thereof to provide a maximum actuating lever arm for the initial lifting movement of the boom, lifting mechanism operatively associated with said mounting member for exerting lifting force on said boom, a shortening link connected at its forward end to said mounting member and at its rear end to said supporting structure in downwardly spaced relation below the pivotal boom mounting, the rear connection of the shortening link with the supporting structure permitting limited free extensibility of said link during the initial lifting movement of said boom but shifting said mounting member toward said boom pivot when this limited initial shifting movement has been reached, and

lmeans permitting the adjustment of said free extensibility to vary the initial operating point of said shortening link.

References Cited in the tile of this patent UNITED STATES PATENTS 2,465,476 Pokorny et al Mar. 29, 1949 2,468,602 Lord Apr. 26, 1949 2,501,797 Ulrich Mar. 28, 1950 2,524,203 Mott Oct. 3, 1950

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