GB2353270A

GB2353270A - Linkage arrangement for a work machine

Info

Publication number: GB2353270A
Application number: GB0015143A
Authority: GB
Inventors: Gerald P Simmons; Daniel L Mikrut; Sridhar Jaganathan; John J Krone; Robert A Eissler
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 1999-06-21
Filing date: 2000-06-21
Publication date: 2001-02-21
Also published as: GB0015143D0

Abstract

A linkage arrangement which utilizes an eight bar design in combination with a box boom 16 type lift arm construction for connecting a work implement 12 to a work machine (14, Fig 1), the present linkage arrangement providing a single linkage system that is compatible for use in a wide variety of different work applications and which, at the same time, yields good performance characteristics in the areas of level lift, rack lift and rack back regardless of the particular type of work implement being utilized. The linkage comprises a second link 50 pivotally intermediately attached to the boom, at one end to a first link 44 (also pivoted onto the machine) and at the other to a tilt cylinder 54. A third link 60 is pivotally connected between the tilt cylinder and implement and is in turn pivotally connected to the boom 16 via a fourth link 66.The boom is raised by a lift cylinder 32 connected below both the boom 16 and the first link 44.

Description

2353270

Description

LINKAGE ARRANGEMENT FOR A LOADING MACHINE Technical Field

This invention relates generally to a boom mechanism for work machines and, more particularly, to a linkage arrangement which utilizes an eight bar design in combination with a box boom type lift arm to connect a work implement to a work machine.

Backround Art In a wide variety of different types of work machines such as wheel and tract type loaders and other earth working machines, a work implement such as a bucket is mounted to the front end portion of the machine by a linkage arrangement that permits the manipulation of the bucket to excavate and load material in a variety of ways. The bucket is typically mounted to the machine by one or more lift arms or booms and is typically lifted in a vertical plane by a pair of hydraulic cylinders that extend between the lift arm and the machine.

Wheel loaders and other work machines of this type currently use several different types of bucket linkage arrangements depending upon load and maneuverability requirements. Some of the known linkage types include a Z-Bar type linkage, an IT (Integrated Tool) type linkage, a T-Bar type linkage, and a Torque Parallel type linkage. A tilting arrangement for the bucket is also provided in one of many different types of linkage arrangements, such tilting linkage being connected between the lift arm and the bucket and being actuated by a tilt cylinder that extends from the work machine to the tilt linkage so as to pivot the bucket with respect to the lift arm.

Both the Z-Bar and IT type linkages require two separate lift cylinders, one cylinder being mounted on either side of a solid lift or boom arm.

This arrangement reduces the load carrying capabilities of the overall work machine due to the added weight of both a solid lift arm as well as the use of two lift cylinders. In addition, use of the ZBar or IT type linkage limits the range of motion of the bucket. Because each specific work application has its own maneuverability requirements, the many different types of known linkage systems have been developed for specific and different functions and characteristics depending upon the particular work application involved. As a result, depending upon the particular application, one type of linkage may provide good level lift capabilities whereas other linkage arrangements may provide good rack lift or rack back capabilities.

In the case of the known linkage systems, the work machine is often times only intended for use with one type of work implement such as a bucket, a pallet type forklift, or a grapple type gripping device for use, for example, in lifting and loading logs. In the case of a bucket implement, a linkage system which provides minimum rack lift variation is important as this particular capability allows the bucket to hold and retain the material captured therewithin during a lifting operation thereby preventing such captured material from exiting the bucket, either fore or aft, as the bucket is lifted and maneuvered during a loading operation. In the case of a pallet type forklift implement, a linkage system which provides a substantially level lift capability is important as this capability allows the pallets to be elevated in a substantially horizontal orientation thereby preventing the load being carried by the forklifts from sliding off of the pallets during a loading operation. Still further, in the case of a grapple type attachment, rack back capability is important so that the grapple may be properly angularly positioned during a log-type loading operation.

Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.

Disclosure Of The Invention

In one aspect of this invention, a linkage arrangement for connecting a work implement to a work machine is disclosed. The linkage arrangement includes a first linkage member having a first end portion pivotally mounted to the work machine and a second end portion pivotally mounted to the work implement and a second linkage member having a first end portion and a second end portion, the first end portion of the second linkage member being pivotally mounted to the work machine and a third linkage member having a first end portion and a second end portion, the third linkage member being pivotally mounted to the first linkage member at an intermediate location between the first end portion and the second end portion of the third linkage member and having the first end portion of the third linkage member pivotally mounted to the second end portion of the second linkage member, a tilt cylinder having first and second end portions, the first end portion of the tilt cylinder being pivotally mounted to the second end portion of the third linkage member, a fourth linkage member having a first end portion pivotally mounted to the second end portion of the tilt cylinder and a second end portion pivotally mounted to the work implement, and a fifth linkage member having a first end portion pivotally mounted to the fourth linkage member at a location intermediate the first end portion and the second end portion of the fourth linkage member and a second end portion of the fifth linkage member pivotally mounted to the first linkage member.

In another aspect of this invention, a method for connecting a work implement to a work machine forming a linkage arrangement is disclosed. The method includes the steps of pivotally mounting a first end portion of a first linkage member to the work machine, pivotally mounting a second end portion of the first linkage member to the work implement, pivotally mounting a first end portion of a second linkage member to the work machine, pivotally mounting 5_ a third linkage member, having a first end portion and a second end portion, to the first linkage member at an intermediate location between the first end portion and the second end portion of the third linkage member, pivotally mounting a first end portion of the third linkage member to a second end portion of the second linkage member, pivotally mounting a first end portion of a tilt cylinder to a second end portion of the third linkage member, pivotally mounting a first end portion of a fourth linkage member to a second end portion of the tilt cylinder, pivotally mounting a second end portion of the fourth linkage member to the work implement, pivotally mounting a first end portion of a fifth linkage member to the fourth linkage member at a location intermediate the first end portion and the second end portion of the fourth linkage member, and pivotally mounting a second end portion of the fifth linkage member to the first linkage member.

Brief Description Of the Drawings

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which:- FIG. 1 is a side elevational view of a linkage arrangement for the operation of a bucket constructed in accordance with the teachings of the present invention; FIG. 2 is a perspective view of the lift arm or box beam member illustrated in FIG. 1; 30 FIG. 3 is a schematic illustration showing the various points of connection between the respective linkage components; FIG. 4 is a graph showing level lift variation for a wheel loader using the present linkage system; FIG. 5 is a graph showing rack lift variation for a wheel loader using the present linkage system; FIG. 6 is a graph showing grapple rack back capability for a wheel loader using the present linkage system; and FIG. 7 is a graph showing the rack velocity is during a dumping operation for a wheel loader using the present linkage system.

Referring now to the drawings and more particularly by reference numbers wherein like numerals refer to like parts, numeral 10 in FIG. 1 represents a linkage arrangement that incorporates the principles of the present invention. The linkage system 10 is provided to connect a work implement 12 to a frame 14 of a particular work machine (not shown). Although it is recognized and anticipated that the present linkage system 10 can be utilized in conjunction with a wide variety of different types of work machines for controlling the movement of a wide variety of different types of work implements, the linkage arrangement illustrated in FIG. 1 and FIG. 3 is by way of illustration and exemplification only wherein the work implement 12 is a bucket of the type that is commonly used in conjunction with a work machine such as a wheel or track type loader.

The present linkage system 10 includes a single support boom or lift arm 16 that is directly positioned between the bucket 12 and the frame 14. The boom 16 is preferably of a box type construction as best illustrated in FIG. 2 and is substantially positioned on a vertical plane that is coincident with a centerline defined by the work machine. The boom 16 has a first bifurcated end portion 18 that defines a pair of spaced apart arms 20 having openings 22 extending respective therethrough for pivotally connecting end portion 18 to the frame 14 at point location A in a conventional manner. An opposite end portion 24 of boom 16 is likewise bifurcated to define a pair of spaced apart arms 26 having openings 28 extending respectively therethrough for pivotally connecting end portion 24 to a pair of spaced plates or flanges 30 associated with a rear portion of the bucket 12 likewise in a conventional manner at point location B. The boom 16 is moved generally along the vertical plane with respect to the work machine by a single lift cylinder 32. Lift cylinder 32 includes a first end portion 34 which is pivotally mounted to the frame 14 at pivot location Y located below pivot location A as shown in FIG. 1 and FIG. 3. A second end portion 36 of lift cylinder 32 is pivotally mounted to a middle portion of the boom 16 between two respective side members 40 and 42 forming a portion of the boom box construction at pivot location K (FIG. 1 and FIG. 3). In this regard, the boom 16 includes a pair of bosses 38 (FIG. 2) for cooperatively engaging the second rod end portion 36 of the lift cylinder 32 at pivot location K. Although a box boom construction is generally preferred, both from a weight reduction standpoint as well as for ease of attaching the second end portion 36 to the middle portion of the boom 16, it is recognized and anticipated that other boom constructions will likewise work equally well so long as second end portion 36 can be pivotally attached to the boom 16 at an intermediate location therealong as best illustrated in FIG. 1.

is The bucket 12 is pivoted about its mounting location B by means of a tilting arrangement which includes a tag linkage member 44, a first tilt linkage member 50, a tilt cylinder 54, a second tilt linkage member 60, and an connecting linkage member 66. The tag linkage member 44 includes a first end portion 46 which is pivotally and cooperatively engageable with the frame 14 at pivot location U and a second end portion 48 which is pivotally attachable to one end portion of the first tilt linkage member 50 at pivot location J. One or both end portions 46 and 48 of the tag linkage member 44 may be bifurcated to facilitate pivotal mounting to either the frame 14 or to the first tilt linkage member 50 depending upon the specific construction of the frame 14 and member 50.

The first tilt linkage member 50 is likewise pivotally connected to the boom 16 at a pivot location H that is substantially intermediate its opposed end portions as best illustrated in FIG. 1. In this regard, the boom 16 includes a pair of bosses 52 (FIG. 2) for cooperatively engaging means associated with the tilt linkage member 50 for pivotally attaching the member 50 to the boom 16 at location H. Although the bosses 52 provide greater strength for the pivot joints at location H, other suitable means for pivotally attaching member 50 to boom 16 may likewise be utilized. The opposite end portion of tilt linkage member So is likewise pivotally connected in a conventional manner to one end portion of the tilt cylinder 54 as will be hereinafter further explained. The geometry and movement of the members 44 and 50 provide greater flexibility and maneuverability with respect to the lift and rack capabilities of the present linkage system 10 as will be later explained.

The tilt cylinder 54 has its one end portion 56 connected to the first tilt linkage member 50 at pivot location G and extends forwardly from the frame 14 along the upper portion of the boom 16 to def ine a second rod end portion 58 which is likewise pivotally connected at pivot location E to one end portion 62 of a second tilt linkage member 60 as illustrated in FIG.

1. The opposite end portion 64 of tilt linkage member 60 is pivotally connected to the upper portion of the bucket flanges 30 at pivot location C in a conventional manner. The pivotal connection between the linkage end portion 64 and the bucket 12 at location C is elevationally above and preferably centered between the spaced bifurcated arms 26 of boom 16 and their pivotal connection to the bucket 12 at location B. A connecting linkage member 66 is also utilized to interconnect the tilt linkage member 60 with the boom 16. In this regard, one end portion of the connecting member 66 is pivotally attached to the member 60 at an intermediate location D therealong whereas the opposite end portion of the connecting member 66 is pivotally attached to the bosses 68 associated with boom 16 at pivot location F which is located adjacent to, but spaced from, pivot location B (FIG. 1). The connecting member 66 provides additional strength, stability and flexibility to the maneuverability and racking of the bucket 12 when the tilt cylinder 54 is actuated. The bucket 12, through its connection with the members 60 and 66, will be pivoted about its mounting location B with the boom 16 when the tilt cylinder 54 is extended and retracted.

Industrial Applicabilit As described herein, the present linkage arrangement 10 has particular utility in certain types of work machines such as wheel loaders, track type loaders, excavators, and other types of work machines which utilize a boom mechanism for controlling the operation of a work implement. In this regard, the work implement may include a loading bucket such as the bucket 12 illustrated in FIG. 1 and FIG. 3, a pallet type forklift, a grapple type gripping device for log loading purposes, a crane arm, or other work implement. As will be hereinafter explained with reference to FIGS. 3-7, the present linkage arrangement 10 is compatible for use in a wide variety of different work applications regardless of the particular type of work implement involved, and provides a maximum amount of flexibility and maneuverability for any given application. In addition, the geometry associated with the present linkage system yields good performance characteristics in the areas of level lift, rack lift and rack back regardless of the implement being utilized.

FIG. 3 represents a schematic illustration of the present linkage system 10 wherein the various pivot connection points A, B, C, D, E, F, G, H, J, U and Y existing between the various linkage components 12, 16, 32, 44, 50, 54, 60 and 66 are clearly illustrated. It has been found that if the ratio of the various linkage lengths ED, DC, GH, HJ, AB, FD, BC, FB, and AH as best illustrated in FIG. 3 are maintained within certain preferred ranges as set forth in Table I below, the geometry of the present linkage arrangement 10 will provide good performance characteristics such as good level lift and low rack lift variation characteristics for a wide variety of different work applications while, at the same time, likewise allowing for the shifting of the weight towards the frame of the work machine to lower the lifting energy required.

TABLE I

RATIO PREFERABLE RANGE ED/DC 0.40 - 0.60 GH/HJ 1.95 - 2.11 GH/AB 0.20 0.25 FD/BC 1.20 - 1.30 FI)/FB 1.25 - 2.00 AH/AB 0.15 0.25 If the ratios set forth in Table I above are maintained within the ranges set forth therein, performance characteristics as illustrated in FIGS. 47 can be achieved.

For example, the level lift variation profile 70 illustrated in FIG. 4 was obtained from actual testing of a wheel loader wherein the present linkage system 10 was utilized to connect a bucket 12 to the work machine frame 14 in accordance with the teachings of the present invention, and wherein the various linkage ratios set forth in Table I above were is maintained within the preferred ranges. FIG. 4 depicts any variation in bucket angle versus the height of the bucket above the ground as the bucket is elevated from its ground level position to its maximum height above the ground. The bucket height is measured relative to the B pin pivot connection located between the boom arm portions 26 and the lower portion of the bucket flange 30 as illustrated in FIG. 1 and FIG. 3. As can be seen from FIG. 4, as the bucket is raised vertically, the variation in bucket 13- angle from its horizontally level 00 position is minimal during its entire vertical ascent and such variation does not exceed approximately + 8%. This is particularly important when the work implement is a pallet type forklift implement wherein it is important that the pallets be lifted in a substantially horizontal orientation or at such an angle that the product or materials stacked on such pallets will not slide off during a loading operation. The +8% variation in bucket or forklift angle from the 00 position represents a slight tilt-back of the bucket or pallet towards the frame 14 of a work machine which, in essence, is beneficial in that such tiltback further aids in holding and maintaining the material or product on top of the pallets. Also, importantly, no negative bucket or forklift angle is achieved during the lift operation, a negative bucket or forklift angle representing a tilting forward of the pallet thereby allowing material or product to exit forward off of the pallet onto the ground or other surface. Good level lift variation characteristics are therefore achieved by the present linkage arrangement 10 in a pallet type forklift application.

FIG. 5 is an example of a rack lift variation profile 72 which was likewise obtained from the actual testing of a wheel loader using the present linkage system 10. As can be seen from FIG. 5, once the bucket 12 has been racked back to approximately 450 in order to hold the material within the bucket, very little variation from the racked back position (bucket angle) results as the bucket is again lifted to its maximum height. This performance characteristic is important when using a bucket type implement since any decrease in bucket angle may cause material to spill out of the front of the bucket, and since any further increase in the bucket angle may cause material to spill out of the backside of the bucket. Here again, good rack lift performance is achieved with the present linkage system 10 in a bucket type application.

FIG. 6 is an example of the grapple rack back capability associated with a wheel loader using the present linkage system 10 in conjunction with a grapple type implement. As can be seen from FIG. 6, the load capability of a grapple implement increases as the grapple angle increases from a -450 to +300. when using a grapple implement, normal pickup of logs or other cylindrical objects occurs with the grapple positioned at an angle between approximately -450 and -300. Once the logs or other objects are positioned within the grapple, the grapple implement is typically racked back to approximately +300 before linkage or boom movement occurs. In the profile 74 illustrated in FIG. 6, the limiting load factor for using the grapple is illustrated at point 76, which occurs at the largest negative grapple angle. This is in contrast with the grapple capability associated with some known linkage systems as represented by profile 78 wherein the limiting load factor associated with such known linkage system occurs at point 80. In other words, the grapple represented by profile 78 -is- will not be able to pick up a load representative of point 81 or a load representative of any point between points 81 and 80 because the load capability decreases between these two reference points on profile 78.

This is not true with respect to profile 74 associated with the present linkage system 10. Good grapple rack back capability is therefore likewise achieved through the use of the present linkage system 10.

FIG. 7 illustrates the rack velocity profile 82 of the bucket 12 during a dumping operation as the bucket is moved from a +450 angle to a -450 angle, which profile 82 was likewise obtained from the actual testing of a wheel loader using the present linkage system 10. As can be seen from FIG. 7, during a dumping operation, as the bucket moves from a tiltback position of approximately +450 to a dump position of approximately -450, the velocity rate or acceleration of the bucket as it approaches the -450 angle dump position actually slows down and decreases.

This deceleration actually helps to prevent the bucket from slamming into its stop position during a dumping operation. The shallowness of the slope of the curve as it approaches the -450 bucket angle position represents this decrease in acceleration as compared to profile 84 which is representative of the rack velocity during a dumping operation associated with a typical known linkage system. This deceleration in rack velocity decreases wear and tear on the linkage and bucket and enhances the overall longevity of the work machine.

As can be seen from an analysis of FIGS. 47, the present linkage system 10 provides good lift and rack characteristics for a wide variety of different work applications requiring the use of work implements such as a bucket, a pallet type forklift, a grapple type gripping device, and still other implements. This is advantageous in that the same linkage system can be utilized with a wide variety of different work implements without sacrificing performance, maneuverability and capability. In addition, use of the present box beam construction as best illustrated in FIG. 2 likewise provides a weight and cost savings as compared to the known linkage systems and allows for use of a single lift cylinder.

As is evident from the foregoing description, certain aspects of the present invention are not limited to the particular details of the examples illustrated herein. It is therefore contemplated that other modifications and applications using other work implements and other means for pivoting either the lift arm or the work implement with respect thereto will occur to those skilled in the art. It is accordingly intended that all such modifications, variations and other uses and applications which do not depart from the spirit and scope of the present invention are deemed to be covered by the present invention.

other aspects, objects and advantages of the present invention can be obtained from a study of the drawings, the disclosure and the appended claims.

Claims

1. A linkage arrangement for connecting a work implement to a work machine comprising: 5 a first linkage member having a first end portion pivotally mounted to said work machine and a second end portion pivotally mounted to said work implement; a second linkage member having a first end portion and a second end portion, said first end portion of said second linkage member being pivotally mounted to said work machine; a third linkage member having a first end portion and a second end portion, said third linkage member being pivotally mounted to said first linkage member at an intermediate location between said first end portion and said second end portion of said third linkage member and having said first end portion of said third linkage member pivotally mounted to said second end portion of said second linkage member; a tilt cylinder having first and second end portions, said first end portion of said tilt cylinder being pivotally mounted to said second end portion of said third linkage member; a fourth linkage member having a f irst end portion pivotally mounted to said second end portion of said tilt cylinder and a second end portion pivotally mounted to said work implement; and a fifth linkage member having a first end portion pivotally mounted to said fourth linkage member at a location intermediate said f irst end portion and said second end portion of said fourth linkage member and a second end portion of said fifth linkage member pivotally mounted to said first linkage 5 member.

2. A linkage arrangement, as claimed in Claim 1, having a lift cylinder with a first end portion pivotally mounted to said work machine and a second end portion pivotally mounted to said first linkage member at a location intermediate said first end portion and said second end portion of said first linkage member.

3. A linkage arrangement, as claimed in claims 1 or 2, wherein said f irst end portion of said second linkage member is mounted to said work machine at a location below a location where said f irst end portion of said f irst linkage member is mounted to said work machine.

4. A linkage arrangement, as claimed in claim 3, wherein said first end portion of said lift cylinder is pivotally mounted to said work machine at a location below a location where said first end portion of said second linkage member is mounted to said work implement.

5. A linkage arrangement, as claimed in claim 4, wherein said first linkage member is of a box construction where said first end portion and said second end portion are bifurcated and each defining a pair of spaced apart arm portions.

6. A linkage arrangement, as claimed in S any of claims 1 to S, wherein said work implement is a bucket.

7. A linkage arrangement, as claimed in any of claims 1 to 5, wherein said work implement is a pallet type forklift.

8. A linkage arrangement, as claimed in any of claims 1 to 5, wherein said work implement is a grapple.

9. A linkage arrangement, as claimed in any of claims 1 to 8, wherein a length between where said first end portion of said fourth linkage member mounts to said tilt cylinder and where said first end portion of said fifth linkage member mounts to said fourth linkage member is defined as a linkage length ED, and wherein a length between where said first end portion of said fifth linkage member mounts to said fourth linkage member and where said second end portion of said fourth linkage member mounts to said work implement is defined as a linkage length DC, with a ratio of said linkage lengths ED/DC being in a range between 0.40 and 0.60.

10. A linkage arrangement, as claimed in any of claims 1 to 9, wherein a length between where said second end portion of said third linkage member mounts to said first end portion of said tilt cylinder and where said third linkage member mounts to said first linkage member is defined as a linkage length GH, and wherein a length between where said third linkage member mounts to said first linkage member and where said first end portion of said third linkage member mounts to said second end portion of said second linkage member is defined as a linkage length HJ, a ratio of said linkage lengths GH/W being in a range between 1.95 and 2.11.

11. A linkage arrangement, as claimed in any of claims 1 to 10, wherein a length between where said second end portion of said third linkage member mounts to said first end portion of said tilt cylinder and where said third linkage member mounts to said first linkage member is defined as a linkage length GH, and wherein a length of said first linkage member between where said first end portion of said first linkage member mounts to said work machine and where said second end portion of said first linkage member mounts to said work implement is defined as a linkage length AB, a ratio of said linkage lengths GH/AB being in a range between 0.20 and 0.25.

12. A linkage arrangement, as claimed in any of claims 1 to 11, wherein a length of said fifth linkage member between where said second end portion of said fifth linkage member mounts to said first linkage member and where said first end portion of said fifth linkage member mounts to said fourth linkage member is defined as a linkage length FD, and wherein a length between where said second end portion of said first linkage member mounts to said work implement and where said second end portion of said fourth linkage member mounts to said work implement is def ined as a linkage length BC, a ratio of said linkage lengths FD/BC being in a range between 1.20 and 1.30.

13. A linkage arrangement, as claimed in any of claims 1 to 12, wherein a length of said f if th linkage member between where said second end portion of said fifth linkage member mounts to said first is linkage member and where said first end portion of said fifth linkage member mounts to said fourth linkage member is defined as a linkage length FD, and wherein a length between where said second end portion of said fifth linkage member mounts to said first linkage member and where said second end portion of said first linkage member mounts to said work implement is defined as a linkage length FB, a ratio of said linkage lengths FD/FB being in a range between 1.25 and 2. 00.

14. A linkage arrangement, as claimed in any of claims 1 to 13, wherein a length between where said first end portion of said first linkage member mounts to said work machine and where said third linkage member mounts to said first linkage member is defined as a linkage length AH, and wherein a length of said first linkage member between where said first end portion of said first linkage member mounts to said work machine and where said second end portion mounts to said work implement is defined as a linkage length AB, a ratio of said linkage lengths A-H/AB being in a range between 0.15 and 0.25.

15. A linkage system for connecting a work implement to a work machine for movement in a generally vertical plane comprising:

a boom member having a first end portion pivotally connected to said work machine and a second end portion pivotally connected to said work implement; a tag linkage member having a f irst end portion and a second end portion, said first end portion of said tag linkage member being pivotally connected to said work machine at a location below a location where said f irst end portion of said boom member pivotally connects to said work machine; a first tilt linkage member having a first end portion and a second end portion, said first tilt linkage member being pivotally connected to said boom member at an intermediate location between said first end portion and said second end portion of said first tile linkage member and having said first end portion of said first tilt linkage member pivotally connected to said second end portion of said tag linkage member, said first tilt linkage member being pivotally connected to said boom member at a location spaced from said first end portion of said boom member; a tilt cylinder having first and second end portions for pivotally moving said work implement with respect to said boom member, said first end portion of said tilt cylinder being pivotally connected to said second end portion of said first tilt linkage member; a second tilt linkage member having a first end portion and a second end portion, said first end portion of said second tilt linkage member being pivotally connected to said second end portion of said tilt cylinder, said second end portion of said second tilt linkage member being pivotally connected to said work implement at a location spaced above a location where said second end portion of said boom member pivotally connects to said work implement; is a connecting member having a first end portion and a second end portion, said first end portion of said connecting member being pivotally connected to said second tilt linkage member at an intermediate location therealong, said second end portion of said connecting member being pivotally connected to said boom member at a location spaced from said second end portion of said boom member; and a lift cylinder having a first end portion and a second end portion for pivotally moving said boom member in a generally vertical plane with respect to said work machine, said first end portion of said lift cylinder being pivotally connected to said work machine at a location below a location where said first end portion of said tag linkage member mounts to said work machine, said second end portion of said lift cylinder being pivotally connected to said boom member at a location intermediate said first end portion and said second end portion of said boom member.

16. A linkage system, as claimed in Claim 15, wherein said boom member is of a box construction having a first end portion and a second end portion that are bifurcated, said first bifurcated end portion of said boom member defining a pair of spaced arm members that are pivotally connectable to said work machine on a vertical plane that is coincident with a center line defined by said work machine, said second bifurcated end portion defining a pair of spaced arm members that are pivotally connected to said work implement.

17. A linkage system, as claimed in Claims 15 or 16, wherein said boom member, said tag linkage member, said first tilt linkage member, said tilt cylinder, said second tilt linkage member, said connecting member, and said lift cylinder are substantially centered along said vertical plane.

18. A linkage system arrangement for connecting a work implement to a work machine substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

19. A method for connecting a work implement to a work machine forming a linkage arrangement comprising the steps of:

pivotally mounting a first end portion of a first linkage member to said work machine; pivotally mounting a second end portion of said first linkage member to said work implement; pivotally mounting a first end portion of a second linkage member to said work machine; pivotally mounting a third linkage member, having a first end portion and a second end portion, to said first linkage member at an intermediate location between said first end portion and said second end portion of said third linkage member; pivotally mounting a first end portion of said third linkage member to a second end portion of said second linkage member; is pivotally mounting a first end portion of a tilt cylinder to a second end portion of said third linkage member; pivotally mounting a first end portion of a fourth linkage member to a second end portion of said tilt cylinder; pivotally mounting a second end portion of said fourth linkage member to said work implement; pivotally mounting a first end portion of a fifth linkage member to said fourth linkage member at a location intermediate said first end portion and said second end portion of said fourth linkage member; and pivotally mounting a second end portion of said fifth linkage member to said first linkage member.

20. A method as claimed in Claim 19, further including the steps of:

pivotally mounting a lift cylinder having a first end portion to said work machine; and pivotally mounting and a second end portion of said lift cylinder to said first linkage member at a location intermediate said first end portion and said second end portion of said first linkage member.

21. A method as claimed in Claims 19 or 20, further including the step of mounting said first end portion of said second linkage member to said work machine at a location below a location where said first end portion of said first linkage member is mounted to said work machine.

22. A method as claimed in any of Claims 19 to 21, further including the step of pivotally mounting said first end portion of said lift cylinder to said work machine at a location below a location where said first end portion of said second linkage member is mounted to said work implement.

23. A method as claimed in any of Claims 19 to 22, wherein said first linkage member is of a box construction where said first end portion and said second end portion are bifurcated and each defining a pair of spaced apart arm portions.

24. A method for connecting a work implement to a work machine forming a linkage arrangement substantially as hereinbefore described with reference to and as shown in the accompanying drawings.