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Publication numberUS2348899 A
Publication typeGrant
Publication dateMay 16, 1944
Filing dateNov 2, 1942
Priority dateNov 2, 1942
Publication numberUS 2348899 A, US 2348899A, US-A-2348899, US2348899 A, US2348899A
InventorsGuignard Ulyss O, Schober Wayne E
Original AssigneePioneer Engineering Works Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
US 2348899 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

4 Sheets-Sheet l awe/rm Uwas O. GumwAzu \mwurz E. 5040382..

U. 0. GUIGNARD ET AL LOADER Flled Nov 2, 1942 ay m, 1944..

16, 1944 u. o. GUIGNARD ET AL 2,348,899

LOADER Filed Nov. 2, 1942 4 Sheets-Sheet 2 Potentea May 16, 1944 LOADER Ulyss 0. Guignard and Wayne E. Schober, Minlis, Minn., assignors to Pioneer Engineering Works, Inc., Minneapolis, Minn, a corporation of Delaware Application November 2, 1942, Serial No. 464,160


This invention relates to improvements in loaders for lifting, carrying and delivering boxes, crates and similar objects.

The primary object of the invention is to provide a tractor mounted device of this nature embodying power actuated means for carrying out, the desired operations of lifting, carrying and delivering or depositing such articles as boxes and crates and with such delicacy of control over all such operations as to permit the delivery of the articles in good order to any point. The loader thus fulfills all of the requirements for an effective means of loading goods in large transport aircraft where such goods, often of a delicate although heavy nature, must be elevated to a considerable height and deposited with great nicety in the cargo space.

Another object is to provide a loader embodying as its lifting elements two pairs of normally parallel arms which may be raised and lowered and by parallel-lever action will maintain the load at a level position, but in which one arm of each pair is arranged for movement about an adjustable and controllable pivot in such manner as to tilt the load as may be required either to hold its securely in place while being transported in an elevated position or as an aid in depositing the load at its desired location. Still another object is to provide in a device of this kind a novel and effective load carrying fork or work holder capable of convenient adjustment to accommo date boxes, crates and other particles of many sizes and forms.

These and other more detailed and specific objects will be disclosed in the course of the following speciflcation, reference being had to the accompanying drawings, in which- Fig. l is a side view of our loader as mounted upon a track laying type of tractor and showing the fork holder or fork in full lines in an elevated position, and in a lowered position in broken lines.

Fig. 2 is a perspective view of one of the load carrying forks.

Fig. 3 is a side elevation, the tractor being shown in dotted lines, and illustrating two positions of the fork as well as the manner in which it is tilted forward or rearward by adjustment of the pivot center of one arm of each pair.

Fig. 4 is a fragmentary sectional view of one end of one of the load carrying arms, showing a modified structure for tilting the load.

Fig. 5 is a front end elevation with the fork in lowered position and showing the tractor in dotted lines.

Fig. 6 is a rear end elevation, again with the tractor shown in dotted lines.

Fig. 7 is an enlarged vertical and cross sectional view taken substantially along the line 1-1 in Fig. 3 illustrating the manner of mounting the load carrying forks in their frame.

Fig. 8 is a vertical, longitudinal section along the line 8-8 in Fig. 7, showing the fork in process of being adjusted.

Fig. 9 is an enlarged end view of one fork locking pin and associated parts.

Fig. 10 is a vertical section through the structure of Fig. 9.

Referring now more particularly and by reference characters to the drawings, we have shown our loader as mounted upon a conventional form of track laying tractor, although it may as well be arranged on the usual wheeled tractor or truck, the vehicle of whatever kind serving not only as the carrier for the loader but providing the power for its operation. The tractor here shown includes a chassis frame A alongside which the tracks B and C are arranged and the usual engine (not shown) is employed, being located rearwardly of the radiator D. Other parts of the tractor will be referred to in the course of this specification in connection with the loader parts secured thereto.

Secured to the back of the tractor chassis A is the main frame or support structure ill of the loader comprising transversely spaced uprights or sides II and I2 which at lower ends are rigidly aihxed in any suitable manner to the chassis and which are further braced by side braces I3 and i4 secured near upper ends of the uprights at I5 and extending forwardly and downwardly therefrom inside of the tracks B and C. At forward ends these braces are secured at 16 to brackets ll welded or otherwise fastened upon a cross beam l8 which is mounted horizontally and transversely between the frame members E of the tractor tracks B and C. The uprights l l and 12 are braced transversely by a header l9 secured at their upper ends and by cross members 20.

As best seen in Figs. 3 and 6 a pair of vertically spaced bracing members 20 for the uprights H and I2 may be joined by front and rear plates 2| and 22 and made liquid tight to provide a tank 23 to carry the fuel for the tractor engine, where the mounting of the loader upon the tractor requires the removal of the fuel tank from its usual position at the rear end. A fiJler opening and cap 24 are of course provided as well as suitable fuel connections to the engine in such case.

. Arranged one at each side of the tractor, in-

wardly of the tracks B and C, are swinging side frames made up of upper arms or booms 28 and 28 and similar lower arms or booms 21 and 28 all of which may be conveniently fabricated of tubular material as here shown. The upper arms 28 and 28 are pivoted on a common transversely and horizontally extending axis at rear ends to the upper end of the frame structure in, the pivot being formed by brackets 29 secured to the uprights II and I2 and in which bracket a pin 88 is journaled as clearly shown.. These pivoted rear ends of the upper arms are joined by a cross mem: ber 8| from which the pin 88 extends, and forward ends of the arms are joined by a forward cross member or yoke 82 welded or otherwise secured. The upper arms are thus formed into a rigid frame which may swing upwardly and downwardly and the lengths are such that the forward cross member 82 will clear the tractor radiator some distance when the arms are lowered. The lower arms 21 and 28 are pivoted at rear ends at 88 between the upper ends of the sides of bell cranks or bell crank levers 84 and 85 which in turn are fulcrumed at 88 upon the uprights II and i2. The lower arms are thus arranged to swing upwardly and downwardly at forward ends in the same planes as the upper arms, the brackets 28 being offset laterally from the uprights II and I2 (Fig. 6) suiflciently to bring this about. The arms of course clear the braces I8 and i4 in their movements.

The forward ends of both pairs of arm are attached to the work holder or load carrier which includes a rigid fork frame 38 including transversely spaced pairs of upright webs or flanges 88 between which the ends of the arms loosely extend. The upper arms 28 and 28 are then pivoted by pins 40 between upper ends of these webs (rearwardly of the cross member 82) while the ends of the lower arms 21 and 28 are pivoted by similar pins 4| between the webs near their lower ends.v The distance between the centers of the respective pivot pins 48 and 4| at each side corresponds to the distance between the pivot axes of the rear ends of the arms so that, the frame 88 being rigid, the arms will have a parallellever action. Thus so long as the bell cranks 84 and 88 are locked in proper positions in which the respective upper and lower arms are substantially parallel as in Fig. 1, by means presently to be described, the fork frame 88 will maintain its upright position without forward or rearward tilting as it is raised and lowered. The fork frame serves as an attachment and mounting for forwardly directed forks or fingers 42 and 48, the exact mounting and arrangement of which will also be presently described. A housing 44 partially encloses the rear pivoted ends of the upper arms and the cross member 8i between the brackets 28.

Extending substantially diagonally between the (normally) parallel upper and lower arms of each swinging frame is a hydraulic cylinder device or ram, designated at 48 and 48 for the respective frames. The rear ends of these rams are pivoted at 41 to the sides or upright members .II and I2 lust above the bell cranks 84 and 88 while the forward ends are pivoted at 48 to brackets 48 secured to the upper arms 28 and 28 immediately to the rear of the fork frame 88. As here shown the rear end portions 88 of the rams constitute the cylinders while forward ends 8| are the plungers working therein, but this arrangement may vary, of course. In any event the construction of the rams is such that when they are reassasaa locked in adjusted positions by smaller hydraulic cylinder and plunger units or rams designated generally at 82 and 88. Each unit comprises a cylinder 84 which is pivoted at a lower end at 88 in a bracket. or hanger 88 depended from the lower end of one of the uprights ii and I2 and from each of which cylinders a plunger 81 extends upwardly as clearly shown. Upper ends of the plungers 81 are pivoted at 88 to the rearwardly extending arms of the bell cranks and the arrangement is obviously such that extension or retraction of these ram plungers will oscillate the bell cranks in vertical planes to adimt the pivots 88 for the lower arms 21 and 28 forwardlyv and rearwardly.

The various rams are supplied with oil or other fluid under pressure for their operation by suitable pumps (not shown) actuated by the tractor engine and as here shown such pumps may be arranged within a forwardly located housing 88 with suitable driving connection made to the forward end of the engine crankshaft as represented at 88. Such arrangement may of course be varied to best suit the tractor upon which the loader is mounted. For controlling the admission of fluid to the rams, and the return of fluid therefrom, suitable valves designated generally at 8| controlled by separate handles 82 and 88 may be employed and may be mounted on the brace i8 convenient to the hand of the tractor operator seated on the seat F. One valve may be used to control fluid flow to and from the ram 48 and 48 and the other valve may similarly control the fluid flow to and from the rams 82 and 88.

An inverted U-shaped arch member or yoke 84 is arranged over the hood and radiator of the tractor and supported thereover' by securing lower ends of its legs 88 at 88 to the brackets ll. This yoke will serve to prevent side sway of the arms when the fork orwork holder is lowered, the arms just nicely clearing the upright portions of the yoke as clearly shown. Diagonal brace 81 are secured at each side between the yoke and the side braces l8 and I4 to further stiffen the structure. Brackets 88 are secured to the side braces i8 and I4 and to frame parts other articles, is placed upon the forks 42 and it may then be raised from the ground, transported to any desired location by the tractor, and finally delivered to its destination as will be clearly evident. The raising and lowering operation will not disturb the level of the forks 42 normally, due to the parallel lever action of the arms, but should it be desired to tilt the forks upwardly at forward ends to hold the load more securely in place while transporting. the rams 82 and 88 may be readily operated to swing the upper ends of the bell cranks 84 and 88 forwardly whereupon the lower arms 21 and 28 will be projected forwardly as seen in the full lines in Fig. 3. The result is to swing the lower end of the fork frame 88 forwardly and the load will obviously be more securely held by the forks in such position particularly in travel over rough terrain. On the other hand the forks 42 may be tilted downwardly at forward ends of the bell cranks rearwardly and correspondingly pull the lower arms 21 and 28 and lower end of the fork frame in a rearward direction as seen in the broken lines in Fig. 3.

All of the adjustments both as to elevating or lowering the load and tilting it forwardly or rearwardly may be carried out with great nicety and delicacy of control making it possible to handle heavy but fragile goods with great ease and facilitating loading or unloading operations of all kinds.

Referring more in detail now to the work holder it is seen that the forks 42 have upwardly turned ends 69 disposed at right angles and which ends are secured in the fork frame 38. This frame includes a lower cross bar or angle i against which the forks may rest and an upper cross bar or angle II .spaced some distance above the lower and disposed forwardly of the vertical plane thereof. The lower cross bar near each end (Figs. 4 and 5) has a. series of notches i2 in its upper edge 13 while the upper bar has a series of narrow flanges or fingers 14 near each end and spaced apart at distances corresponding to the spacing of the notches, these flanges being positioned on a rear side of the upper bar and in vertical alignment with the corresponding notches below.

The ends 69 of the forks near their lower extremities have rearwardly projecting bosses or shoulders i5 on rear surfaces of which are detachably mounted the retainer plates 16, by means of bolts 71. Said plates overhang the bosses forming downwardly opening grooves 18 adapted to loosely receive and bear upon the upper edge 13 of the bar 12 as best seen in Fig. 8. A pin or dowel 19 on each plate 76 protrudes into the groove I8 to engage any one of the notches '52, this pin forming a rib beneath the boss above.

The upper extremities of the fork ends 69 have upright, upwardly opening notches 80 adapted to receive and engage the fingers M. The vertical distances between the pins 19 and notches W are such that when the boss bears on the upper edge of the lower cross bar it! the notches at will just nicely receive the proper fingers 14 above, thus preventing either upward or downward displacement of the forks. At the same time the retainer plates 16 overhanging the rear notched ends of the forks are each cut orrounded off on a radius as indicated at 8|, so that the forks may be tilted to either side (Fig. 7) to facilitate their movement laterally in the frame.

To prevent rearward swinging movements of the notched ends of the forks we provide retaining pins or keys 8.2 which may be inserted through horizontally and transversely aligned openings 83 in the, upright end and center members 84 and 85 of the fork frame, one pin being thus mounted at each end of the frame behind the upper end portion of each fork as clearly shown. The inner ends of these pins 82 have reduced portions or grooves 86 which may engage lugs 81 welded on the center frame members 85 to partially close the openings 83 therein, the heads 88 thus formed on the pins, by these grooves, overhanging the lugs to prevent the pins from being drawn outwardly. However, the heads 88 are flattened on one side, as indicated at 89, so that, by rotating the pins one half turn, these flats will clear the lugs 81 permitting of the lower cross bar 10 will prevent either forward or rearward dislodgement of the forks, it being noted that the forks bear rearwardly on the lower cross bar ill and forwardly on the upper bar Ii under load to better support the weight.

To adjust the forks they may be swung upwardly at forward ends, as seen in Fig. 8, to swing the notched upper ends rearwardly clear of the fingers l4 whereupon they may be lifted sufliciently to clear the pins 19 from the notches it. Then the forks may be shifted laterally along the lower bar it, as seen in Fig. 7, to positions in alignment with any of the notches and fingers and restored to operative position by dropping the pins into the desired notches and releasing the front ends of the forks so that of their own weight they will swing forwardly at upper notched ends into reengagement with the fingers H. The ends 69 are, of course, of such length that they may be lifted, when cleared from the fingers I4 to clear the pins 19 as described, while remaining within the limits imposed by the upper cross bar 1|, and these outward withdrawal of the pins when adjusting the forks, The outer ends of the pins 82 have ends turned at right angles forming handles for their manipulation and in the locked position of the pins these ends will hang downwardly. their weight serving to maintain the locked condition of the parts. To remove the pins the ends 90 are grasped and turned upwardly (Fig. 7) and then pulled outwardly as will be apparent.

Referring particularly now to Fig. 4 we have shown therein a modification of the fork tilting means wherein a hydraulic ram 9!, having a plunger 92, is arranged and secured by a pin 93 in the forward end of each lower arm 21 of the swinging side frames. The lower pivot ll for the fork frame 38 is then caried by an extension or and member 94 slidably mounted in the open end 95 of the arm and having a bore 96 to receive the plunger but with the bore plugged as at 9'! to engage the plunger end. Obviously by operation of the ram 9! to extend or retract the plunger 92, the end member 94 may be projected forwardly or moved rearwardly (by weight of the fork) so that the fork frame will swing about its upper pivots 40 to bring about the desired forward or rearward tilting movements. The ram and sliding end member might equally well be arranged at the rear end of the arm or at either end of the upper arm as will be apparent.

It will be noted that the pivot centers 33- for the lower arms are located forwardly of the vertical planes of the corresponding pivot centers 3i-40 for the upper arms. As a result the forward ends of the lower arms are given the necessary forward projection so that the fork frame may clear the front of the tractor as it is raised and lowered, while permitting the fork structure as a whole to be placed closely adjacent the tractor front where the weight of the load will exert the least possible raising leverage upon the tractor. Of equal, or greater importance, this arrangement provides the widest possible spacing between the arms in their raised positions, enhancing their truss effect, as will be evident.

It is understood that suitable modifications may .be made in the structure as disclosed, provided such modifications come within the spirit and scope of the appended claims. Having now therefore fully illustrated and described our invention,

' what we claim to be new and desire to protect by Letters Patent is:

i. A tractor mounted loader comprising a frame supported rearwardly on the tractor, a load carrier disposed forwardly of the tractor, longitudinally extending vertically spaced, substantially parallel boom arms pivotally mounted at their rear ends on the frame and pivotally connected at their forward ends to the load carrier, said frame, carrier and boom arms forming an articulated substantial parallelogram construction which when actuated to raise and lower the carrier will retain the latter in predetermined working angle, an extensible lifting ram disposed entirely within the vertical limits of the boom arms and extending diagonally of such parallelogram and connecting the frame to one of said arms, and power means for operating the lifting ram to thereby actuate the parallelogram construction and operate the carrier.

2. A tractor mounted loader comprising a frame member mounted on the rear of the tractor, vertically spaced, substantially parallel booms extending forwardly from pivot connections with said frame member, a load carrier supported by the forward ends of the booms and connected thereto by spaced pivots, and a fluid operated lifting ram directly connecting said fram member, at a point spaced between the rear ends of the booms, to the upper of said booms, and disposed anE -flarly with respect thereto whereby extension of the ram will operate to lift the booms and load carrier.

3. In a tractor mounted loader, a frame, a boom extending forwardly from a pivot connection with the frame, a load carrier pivotally attached at its upper end to the forward end of the boom. an extensible fluid operated ram forming a diagonal lift connection between the frame and a forward greases part of the boom, and a longitudinally adjustable arm connecting a lower part of the load carrier to the frame. said arm being in substantial parallelism with the boom to thereby maintain a predetermined working angle of the load carrier when the latter is raised and lowered.

4. In a tractor mounted loader, a frame, a boom extending forwardly from a pivot connection with the frame, a load carrier pivotally attached at its upper end to the forward end of the boom, an extensible fluid operated ram forming a diagonal lift connection between the frame and a forward part of the boom. and an arm connecting a lower part of, the load carrier to the frame, said arm being in substantial parallelism with the boom to thereby maintain a predetermined working angle of the load carrier when the latter is raised and lowered, and fluid operated means associated with said arm to tiltably adjust the angle of the load carrier.

5. In a tractor mounted loader, a frame, aboom extending forwardly from a pivot connection with the frame, a load carrier pivotally attached at its upper end to the forward end of the boom, an extensible fluid operated ram forming a diagonal lift connection between the frame and a forward part of the boom, and an arm connecting a lower part of the load carrier to the frame, said arm being in substantial parallelism with the boom to thereby maintain a predetermined working angle of the load carrier when thelatter is raised and lowered and fluid operated meansassociated with said arm to tiltably adjust the angle of the load carrier, said means comprising a lever fulcrumed on the frame with one part supporting said arm, and a fluid operated ram connecting said lever to

Referenced by
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U.S. Classification414/712, 414/743, 414/667
International ClassificationE02F3/34, E02F3/28
Cooperative ClassificationE02F3/3408
European ClassificationE02F3/34L2