CA2046507A1 - Quick coupler - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A quick coupler is described for coupling a front end loader to any of a variety of implements. The coupler includes a loader portion connected to the front-end loader and a cooperating implement portion connected to any of various implements. The loader portion of the implement includes one main crossmember located vertically between the upper and lower arms of the front-end loader. The coupler is designed to avoid extending the load further from the front-end loader than if no coupler were used. The coupler includes a centralized two point pick-up which facilitates rapid coupling.

Description

2 ~ Q 7 .
OUICK ~Q~LER

Backqround of the Invention l. Field of the invention.
This invention relates to couplers, and more particularly, to couplers for quickly coupling any of a variety of implements to the arms of front-end loaders.
2. ~escription of the related art.
Front-end loaders are powered vehicles running on wneels or tracks having hydraulically operated arms extending from the front of the vehicle. The arms operate to perform useful work by means of attached implements such as a bucket, scoop, plow, fork, or the like. It is often desirable to quickly change imple-ments with minimal effort by the operator, and quick couplers have been developed for this purpose. Such coupler systems have two mating parts: a loader portion mounted on the arms of a front-end loader and an implement portion which is duplicated on the bacX of various implements so that any implement may be selected and carried by the loader portion. ~Jsually, the operator may disengage one implement and engage another without leaving his or her seat.
Prior art quick couplers typically extend the distance from the front-end loader to the center of gravity of the implement. Some couplers have been known to extend the distance of attachment by as much as twenty four inches beyond its original design location.
Extending the center of gravity of the implement further _ away from the front-end loader adversely effects the loader's performance. Stability, tipping load, and break-out force are all reduced by couplers that extend the center of gravity of the payload.
In one prior art design disclosed in U.S. Patent No. 4,708,579, an attempt was made to maintain the original design position of the implement's center of gravity. This design employed a contoured face plate .

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2 ~ ~ ~r ~ 1~ Q 7 which formed the ~backbone~ of the coupler. While this design reduced the problems associated with the extension of the implement attachment points, it nevertheless extended the implement's center of gravity approximately one and one half to two inches beyond its original design location.
Front end loader manufacturers have chosen different arm configurations on their machines.
Therefore, a quick coupler must be designed for a lo specific brand or style of front-end loader with respect to the locations of the arms. Many prior art quick couplers have engagement points or pick-up points between the two parts of the quick coupler which are structurally related to the pivot joints where the loader arms connect with the coupler. This design limits a set of implements to use with a specific style of front-end loader. If a different front-end loader is acquired, not only must a new coupler be purchased, but the existing implements must be altered or replaced or a redundant set must be purchased to match the new coupler.
Many prior art quick couplers have pick-up points between the two coupler parts which are laterally spread apart a substantial distance. This design has provided adequate strength, however, a great amount of maneuver-ing by the operator is required prior to coupling to move both pick-up points into alignment. In particular, when the implement to be coupled is resting on uneven ground, a great deal of manipulation is required to properly align the loader portion with the implement portion. Single pick-up point couplers were designed to permit the operator to drive up to a single self-aligning connection point. While this design permitted easier coupling, the strength of the connection between the two coupler parts was compromised to permit a single connection point.

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2~6~7 Many prior art couplers have a horizontal support member mounted near the top of the coupler near where the upper loader arms are attached. When a fork-lift attachment is mounted to the coupler, the horizontal support member blocks the operators view of the forX
tines making it more difficult for the operator to align the attachment with a load.
The present invention provides a new and useful quick coupler which overcomes the above disadvantages of lo prior art designs.

Summary of the Invention An object of the present invention is to provide a quick coupler for coupling various implements to the arms of a front-end loader without extending the center of gravity of the implement beyond its original design location.
Another object of the invention is to provide a coupler having a single main support member.
A further object of the invention is to provide a quick coupler with two centralized pick-up points between the two coupler parts to allow rapid self-aligning coupling and minimal operator manipulation.
A further object of the invention is to provide a coupler having pick-up points between the coupler parts which are structurally independent of the front-end loader arm connection points.
Another object of the invention is to provide a _ coupler which allows the operator optimal visibility between the front-end loader arms.
In a preferred embodiment, the invention comprises .
a coupler adapted to join a variety of implements to a front-end loader, the front-end loader having a plurality of lower arms and at least one upper arm. The arms are adapted to pivotally support the coupler. The coupler includes a loader portion adapted to be coupled ..... . . .

-' ' , : '- ,: , ' 4 2~65Q7 to the arms and an implement portion cooperating with the loader portion and adapted to be secured to any of the variety of implements. The coupier is pivotally connected to the arms about an upper pivot axis and a lower pivot axis spaced from and parallel to the upper pivot axis. The implement portion includes a coupling structure for engaging the loader portion. The loader portion includes a crossmember having a longitudinal axis parallel to the upper and lower pivot axes. The loader portion further includes a coupling member mounted on the crossmember for engaging the coupling structure on the implement portion such that the majority of the weight of the implement portion is transferred to the crossmember. The loader portion further includes an upper arm pivot structure fixed to the crossmember for pivotally connecting the upper arm(s) to the loader portion and lower arm pivot structure fixed to the crossmember for pivotally connecting the lower arms to the loader portion. The longitudinal axis of the crossmember is vertically located in a range approximately between one third and two thirds of the distance between the upper and lower pivot axes.
The coupling member of the preferred coupler has hook-engaging surfaces which are horizontally located in a range within the central two-fourths of the width of the coupler.
The crossmember of the preferred coupler is the sole member on the loader portion spanning the distance 30 - between the points where the lower loader arms are connected.
~The preferred coupler further includes locking devices for locking the implement portion to the loader portion.
Other objects and advantages and a fuller under-; standing of the invention will be had from the following . . : , ' .

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5 2~6~7 detailed description of a preferred embodiment and the accompanying drawings.

Brief Description of the Drawings Figure 1 is a perspective view of the quick coupler in an uncoupled state;
Figure 2 is a side elevational view of a prior art coupler (below) and the coupler of the present invention (above);
lo Figure 3 is a side elevational view of the quick coupler with an implement shown in dashed lines;
Figure 4 is a rear elevational view of the loader portion of the quick coupler;
Figure 5 is a side elevational view seen approx-imately from the plane indicated by the line 5-5 of Figure 4;
Figure 6 is a cross-sectional view seen approx-imately from the plane 6-6 of Figure 4;
Figure 7 is a cross-sectional view seen approx-imately from the plane indicated by the line 7-7 of Figure 4;
Figure ~ is a side elevational view of the quick coupler shown fully coupled to an implement;
Figure 9 is a rear elevational view seen approx-imately from the plane indicated by the line 9-9 of Figure 8:
Figure 10 is a rear e~evational view of the implement portion of the quick coupler;
Figure 11 is a side elevational view seen approxi-30 _ mately from the plane indicated by the line ll-ll of Figure 10;
Figure 12 is a side elevational view of a second embodiment of the loader portion of the coupler of the present invention;
Figure 13 is a rear elevational view o~ the loader portion of Figure 12 with the loader arms removed;

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2~6~7 Figure 14 is a side elevational view seen ap-proximately from the plane indicated by the line 14-1 of Figure 13;
Figure 15 is a cross-sectional view seen ap-proximately from the plane 15-15 of Figure 13;
Figure 16 is a cross-sectional view seen ap-proximately from the plane indicated by the line 16-16 of Figure 13;
Figure 17 is a side elevational view of the quick coupler of the second embodiment shown fully coupled to an implement; and Figure 18 is a rear elevational view seen approx-imately from the plane indicated by the line 18-18 of Figure 17.
Description of the Preferred Embodiment Referring now to the drawings, and to Figure l in particular, a coupler embodying the present invention is generally designated by reference numeral 10. The coupler 10 comprises two portions: a loader portion 20 and an implement portion 30. The loader portion 20 is constructed for attachment to the arms 40, 50, 60 of a front-end loader (not shown). The implement portion 30 is constructed to be joined to an implement such as a bucket 70 shown in dashed lines in Figure 1. A pair of closely spaced hooks 80,90 on the implement portion 30 engage the loader portion 20 to couple the loader portion 20 to the implement portion 30. The operator of the front-end loader may readily couple or uncouple the 30 ~ two portions 20, 30 to change implements by maneuvering the loader portion 20 into engagement with the implement portion 30.
A front-end loader arm configuration having one : upper arm 40 and first and second lower arms 50, 60, respectively, is illustrated in Figures 1-8. As shown in Figure 3, each arm 40, 50, 60 has a hole at its outer 7 2~46~07 end adapted to receive a pin 100 for pivotally connect-ing the coupler 10 to the arms 40, 50, 60 in a manner well known in the art. The pin 100 connecting the upper arm 40 to the coupler 10 defines an upper pivot axis llo. The pins lO0 connecting the lower arms 50, 60 to the coupler lo define a lower pivot axis 120 which is parallel to the upper pivot axis llo.
In the embodiment illustrated in Figures 1-9, the loader portion 20 comprises a crossmember 140; a coupling member 150; an upper arm pivot joint 160; first and second lower arm pivot joints 170, 180, respective-ly; and a pair of locking mechanisms lso. In general, the loader portion 20 adapts the ends of the loader arms 40, 50, 60 to fit a specialized cooperating structure, i.e., the implement portion 30. The loader portion ~o serv~s to transmit the load of the implement portion 30 to the front-end loader arms 40, 50, 60 when an implement is attached.
The crossmember 140 forms the main support of the loader portion 20 and bears the weight of the implement portion 30. The crossmember 140 is preferably a hollow cylindrical tube but may be rectangular or otherwise in cross section. The crossmember 140 includes a first end 200, a second end 210, and a longitudinal axis 220 which is parallel to the upper and lower pivot axes 110, 120.
The crossmember 140 is the sole structural member spanning the width o~ the loader portion 20 and is thus the only structural member resisting torsional and other stresses acting on the loader portion 20 between the 30 - arms 50,60.
In general, the vertical location of the crossmem-ber 140 is determined by a compromise between multiple competing design factors. For example, the vertical position of the crossmember 140 affects the maximum dump height of the loader since the upper loader arm 40 inter~eres with the crossmember when the arms 40, 50, 60 .
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8 2~5Q7 - are fully raised. Thus, while there is some design flexibility in locating the crossmember 140, in general, it is desired to locate the crossmember 140 approximate-ly ~idway between the upper and lower pivot axes llo, 120. The longitudinal axis 220 of the crossmember 140 is preferably vertically located in a range of positions approximately between one-third and two-thirds of the distance between the upper and lower pivot axes 110, 120. Figure 4 illustrates the crossmember 140 posi-tioned within the preferred range.
As best illustrated in Figures 1 and 4, the coupling member 150 comprises a structure mounted on the crossmember 140 for receiving the hooks 80,90 of the implement portion 30. The coupling member 150 is mounted centrally on the crossmember 140 and extends upwardly therefrom. The coupling member 150 transfers substantially all of the weight of the implement portion 30 and any load it may be carrying to the crossmember 140. The coupling member 150 comprises two closely spaced hook-engaging surfaces 230. The hook-engaging surfaces 230 are located on opposite sides of a plane normal to the longitudinal axis 220 bisecting the loader portion 20. The hooX-engaging surfaces 230 are symmetrically and centrally located and closely spaced with respect to each other. Centrally located hook-engaging sur~aces 230 allow the quick coupler 10 to mimic a single point pick-up and gain the advantages of easy coupling inherent in single point pick-up systems.
The quick coupler 10 of the present invention further 30 ~ gains the added strength of two load-bearing hooks 80, 90 and two cooperating hook-engaging surfaces 230.
Preferably, the hook-engaging surfaces 230 are horizon-- tally located approximately in a range withln the middle two-Pourths o~ the distance between the lower loader arms 50, 60. Figure 3 illustrates a horizontal :

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~ ~ 2 ~ 0 7 g location of the hook-engaging surfaces 230 within the preferred range.
As seen in Figure 4, the coupling member l5o of the preferred and illustrated coupler lo comprises a T-shaped structure having two vertical parallel plate members 240, 250, each welded or otherwise secured at one end to the mid-section of the crossmember 140 and, at the opposite end, to a hook-receiving member 260 forming the hook-engaging surfaces 230. The vertical lo plate msmbers 240, 250 determine the position of the hook-receiving member 260 and transmit the implement's load on the hook-receiving member 260 to the crossmember 140. The hook-receiving member 260 is preferably formed by a cylindrical member fitted into holes formed in the vertical plate members 240, 250 such that its lon-gitudinal axis 270 is parallel to and spaced from the longitudinal axis of the crossmember 140.
The hooks 80, 90 and the cooperating hook-engaging surfaces 230 are formed to be self-aligning. Tapered shoulders 280 are formed at the juncture between the hook-receiving member 260 and the vertical plate members 240, 250 to laterally guide the hooks 80, 90 into centered engagement with the hook-engaging surfaces 230.
In addition, the round cross sectional shape of the hook-receiving member 260 in cooperation with the sloping entrance ways 290 of the hooks 80, 90 serves to align the seating of the hooks 80, 90 on the hook-receiving member 260.
As illustrated in Figures 1 and 4, the upper arm pivot joint 160 is located above the crossmember 140 for pivotally connecting the upper loader arm 40 to the loader portion 20. The upper arm 40 pivot joint includes a plurality of openings 300 aligned with the upper pivot axis 110, each adapted to receive a portion of one of the pins 100 for pivotally connecting the upper arm 40 to the coupler 10. As illustrated in . ~", .

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2~65Q7 Figures 1, 7 and 8, the upper arm pivot joint 160 is formed in the vertical plate members 240, 250 of the coupling member 150. One of the openings 300 is formed in each vertical plate member for receiving one of the pins 100 which bridges the vertical plate members 240, 250. The upper arm 40 is rotatably coupled between the vertical plate members 240, 25n about the pin 100.
As illustrated in Figures l and 3, the lower arm pivot joints 170, 180 are formed by a pair of inner vertical plates 310, 320 and a pair of outer vertical plates 330, 340. A first inner vertical plate 310 and a first outer vertical plate 330 are located proximate the first end 200 of the crossmember 140 in parallel spaced relation. In mirror image fashion, a second inner vertical plate 320 and a second outer vertical plate 340 are located proximate the second end 210 of the crossmember 140 in a spaced, parallel relationship.
Each of the inner and outer vertical plates 310, 320, 330, 340 has openings 350 aligned with the lower pivot axis 120. Each opening 350 is adapted to receive a portion of one of the pins 100 which bridge the inner and outer vertical plates. The inner and outer vertical plates are spaced apart sufficiently to permit the outer ends of the lower arms 50,60 to fit therebetween when the coupler 10 is connected to the arms 40, 50, 60.
Upper spacers 360 and lower spacers 370 are welded or otherwise secured between the inner vertical plates 310, 320 and outer vertical plates 330, 340 for holding the plates together and for setting the spacing therebet-30 _ ween.
The locking mechanisms 190 include a pair of extendable and retractable locking pins 380 as shown in Pigure 4. When extended, the locking pins 380 fit within apertures 390 (Figure 3) located on the implement portion 30 to lock the implement portion 30 in place.
The locking pins 380 do not bear the weight of the load 11 2~6S~7 and are thus easily movable between extended and retracted positions. In the preferred and illustrated embodiment, the longitudinal axes of the extendable locking pins 380 are in alignment with the lower pivot axis 120 for manufacturing efficiency.
The locking pins 380 may be extended and retracted manually, hydraulically, pneumatically or electrically.
In the illustrated embodiment, a solenoid 400 is connected to each locking pin 380 and is operable to lo retract or extend the locking pins 380 in response to a signal by the operator from the seat of the front-end loader.
As best illustrated in Figures 10 and 11, the implement portion 30 comprises an upper part 410 and a lower part 420. Both upper and lower parts 410, 420 are welded or otherwise secured to the various implements to be used. The upper part 410 comprises the two closely spaced hooks 80, 90. Each hook includes a downwardly extending leg 424. The hooks 80, 90 are centrally located to align with the hook-engaging surfaces 230 on the loader portion 20.
The lower part 420 includes a pair of extensions 430 having apertures 390 therein. The extensions 430 are constructed and arranged such that the apertures 390 are aligned with the locking pins 380 when the loader portion 20 and implement portion 30 are fully coupled.
The lower part 420 further includes a pair of laterally spaced abutments 440 which engage the lower spacers 370 for transmitting forces between the implement portion 30 30 - and the loader portion.
The arrangement of the crossmember 140 and the inner and outer plates 310, 320, 330, 340 permits the coupler 10 to fit between the loader arms 40, 50, 60 without extending the payload center of gravity 442 further from the front-end loader than it would be without a coupler. Figure 2 illustrates a bucket 70 ~. .

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12 2~6~7 attached directly to the arms of a front end loader in the lower view. The upper view shows the coupler 10 coupling the bucket 70 to the loader arms 60. In both views of Figure 2, the distance D from the payload center of gravity 442 to the lower pivot axis is the same.
In a second embodiment illustrated in Figures 12-18, the loader portion, designated generally by reference numeral 450, is constructed to fit a front-end loader having an arm configuration comprising two upper arms 460, 470 and two lower arms 50, 60. The loader portion 450 of the second embodiment differs from the loader portion 20 of Figures 1-9 in that two upper pivot joints 480, 490 are provided for connecting two upper arms 460, 470 to the loader portion rather than one.
The loader portion 450 of Figures 12-18 is otherwise the same as that discussed above with reference to Figures 1-9. Parts which are unchanged between the two embodiments have the same reference characters.
Referring in particular to Figure 18, a loader portion 450 is shown attached to a pair of upper loader arms 460, 470 and a pair of lower loader arms 50, 60.
The loader portion 450 is pivotal with respect to the upper arms 460,470 about an upper pivot axis 500 and with respect to the lower arms 50, 60 about a lower pivot axis 120 which is parallel to and spaced from the upper pivot axis 500.
As in the embodiment of Figures 1-9, lower arm pivot joints 170, 180 illustrated in Figure 18 are formed bv a pair of inner vertical plates 590, 550 and a pair of outer vertical plates 560, 570. A first inner vertical plate 540 and a first outer vertical plate 560 are located proximate the first end 200 of the crossmem-ber 140 in parallel spaced relation. In mirror image fashion, a second inner vertical plate 550 and a second outer vertical plate 570 are located proximate the .,Y~,:

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' second end 210 of the crossmember 140 in a spaced, parallel relationship. Each of the inner and outer vertical plates 540, 550, 560, 570 have openings 350 aligned with the lower pivot axis 120 for supporting pins 100 rotatably joining the lower arms 50, 60 to the loader portion 450.
As best illustrated in Figure 18, the vertical plates 540, 550, 560, 570 extend upwardly above the crossmember 140 to form the upper pivot joints 480, 490.
Openings 580 are formed in the plates 540, 550, 560, 570 in alignment with the upper pivot axis 500 for receiving pins 100 which rotatably support the upper arms 460, 470 in the manner of the lower pivot joints 170, 180.
While a single preferred embodiment of the invention has been illustrated and described in detail, the present invention is not to be considered limited to the precise construction disclosed. Various adapta-tions, modifications and uses of the invention may occur to t~ose skilled in the art to which the invention relates and the intention is to cover hereby all such adaptations, modifications and uses which fall within the spirit or scope of the appended claims.

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Claims (13)

1. A coupler adapted to join a variety of implements to a front-end loader, said front-end loader having a plurality of lower arms and at least one upper arm, each arm being adapted to pivotally support said coupler, wherein said coupler comprises a loader portion adapted to be coupled to said arms and an implement portion cooperating with said loader portion and adapted to be secured to any of said variety of implements, and wherein said coupler is pivotally connected to said arms about an upper pivot axis and a lower pivot axis spaced from and parallel to said upper pivot axis;

said implement portion including first coupling means for engaging said loader portion; and, said loader portion including:
a crossmember having a longitudinal axis parallel to said upper and lower pivot axes;

second coupling means mounted on said crossmember for engaging said first coupling means such that said second coupling means transfers the majority of the weight of said implement portion to said crossmember;

upper arm pivot means fixed to said crossmem-ber for pivotally connecting said at least one upper arm to said loader portion;

lower arm pivot means fixed to said crossmem-ber for pivotally connecting said lower arms to said loader portion; and wherein said longitudinal axis is vertically located in a range approximately between one third and two thirds of the distance between said upper and lower pivot axes.

2. A coupler according to claim 1 wherein said coupler includes locking means connected to said crossmember for selectively locking said implement portion to said loader portion.

3. A coupler according to claim 2 wherein said locking means comprises at least one extendable locking pin adapted to extend laterally from said loader portion and at least one extension formed on said implement portion having an aperture formed therein such that said aperture aligns with and is engageable with said extendable locking pin when said implement portion is coupled to said loader portion.

4. A coupler according to claim 1 wherein said lower arm pivot means comprises a pair of inner vertical plates and a pair of outer vertical plates, wherein one of said inner vertical plates and one of said outer vertical plates are disposed in parallel spaced relation proximate each end of said crossmember, and wherein each of said lower arms is rotatably pinned between an inner vertical plate and an outer vertical plate about said lower pivot axis.

5. A coupler according to claim 1 wherein said second coupling means is comprised of a T-shaped structure mounted symmetrically with respect to a vertical plane normal to said longitudinal axis and bisecting said coupler, said second coupling means having a horizontal member, and a vertical support means fixed at one end to the mid-section said crossmember and at the opposite end to the mid-section of said horizon-tal member, wherein said horizontal member has hook-receiving surfaces located on each side of said bisecting plane.

6. A coupler according to claim 5 wherein said vertical support means is comprised of a pair of spaced plates, each in a plane lying normal to the longitudinal axis of said crossmember and equidistant from said bisecting plane, and wherein said upper arm pivot means include a single upper arm pivot joint connecting a single upper arm to said loader portion and wherein said upper arm pivot joint is connected to said crossmember by said pair of spaced plates.

7. A coupler according to claim 5 wherein said hook-receiving surfaces are horizontally located in a range within the central two fourths of the width of the coupler as measured in the direction of the longitudinal axis of said crossmember.

8. A coupler according to claim 1 wherein said front end loader comprises one upper arm and wherein sald upper arm pivot means is constructed and arranged to couple said one upper arm to said loader portion at a position midway between said lower arms.

9. A coupler according to claim 1 wherein said crossmember is a cylindrical tube.

10. A coupler according to claim 1 wherein said loader portion comprises a first lower arm pivot joint for connecting a first lower arm to said loader portion and a second lower arm pivot joint for connecting a second loader arm to said loader portion, and wherein said crossmember is the sole member on said loader portion spanning the distance between said first lower arm pivot joint and said second lower arm pivot joint.

11. A coupler adapted to join a variety of implements to a front-end loader, said front-end loader having a plurality of arms, each arm being adapted to pivotally supporting said coupler, wherein said coupler comprises a loader portion adapted to be coupled to said arms and an implement portion cooperating with said loader portion and adapted to be secured to any of said variety of implements, and wherein said coupler is pivotally connected to said arms about an upper pivot axis and a lower pivot axis spaced from and parallel to said upper pivot axis, said upper and lower pivot axes defining a vertical reference plane;

said implement portion including first coupling means for engaging said loader portion; and, said loader portion including:
a crossmember having a first end, a second end and a longitudinal axis parallel to said upper and lower pivot axes;

a second coupling means mounted on said crossmember and extending upwardly from said crossmember for engaging said first coupling means such that said second coupling means transfers the majority of the weight of said implement portion and its load to said crossmember, wherein said second coupling means includes a plurality of spaced coupling surfaces, each coupling surface being horizontally located within the middle two fourths of the width of the coupler;

upper arm pivot means fixed to said crossmem-ber for pivotally connecting at least one of said arms to said loader portion; and lower arm pivot means fixed to said crossmem-ber for pivotally connecting two lower arms to said loader portion.

12. A coupler according to claim 11, wherein said first coupling means comprises two spaced hooks, each having a downwardly extending leg for engaging one of said coupling surfaces.

13. A coupler adapted to join a variety of implements to a front-end loader, said front-end loader having a plurality of lower arms and at least one upper arm, each arm being adapted to pivotally support said coupler, wherein said coupler comprises a loader portion adapted to be coupled to said arms and an implement portion cooperating with said loader portion and adapted to be secured to any of said variety of implements, and wherein said coupler is pivotally connected to said arms about an upper pivot axis and a lower pivot axis spaced from and parallel to said upper pivot axis;

said implement portion includes means for coupling said implement portion to said loader portion; and, said loader portion including:
a crossmember having a first end and a second end, implement support means mounted on said crossmember such that substantially all the weight of said implement and its load is transferred to said crossmember;

upper arm pivot means fixed to said crossmem-ber for pivotally connecting said at least one upper arm to said loader portion;

lower arm pivot means fixed to said crossmem-ber for pivotally connecting said lower arms to said loader portion; and a first lower arm pivot joint for connecting a first lower arm to said loader portion and a second lower arm pivot joint for connecting a second loader arm to said loader portion and wherein said first and second lower arm pivot joints are connected to said crossmember proximate its first and second ends, respec-tively, and wherein said crossmember is the sole member on said loader portion spanning the horizontal distance between said first and second lower arm pivot joints.