Main frame for a tracked skid steer loader machine

A frame for a tracked skid steer loader machine or multi-terrain loader machine is provided having a structural design that enables the loader machine to be modularly assembled using a variety of pre-assembled components, namely a lower frame assembly, an upper frame assembly and an undercarriage. The lower frame assembly includes a pair of recessed channels formed on a base portion of the lower frame assembly and extending the width of the lower frame assembly. The undercarriage includes right and left track assemblies connected by a pair of crossmembers. Each recessed channel is engagingly associated with a respective crossmember of the undercarriage, thereby allowing for the modular assembly of a loader machine when the recessed channels of the lower frame assembly are mounted over the crossmembers of the undercarriage. An upper frame assembly may be mounted on the lower frame assembly before or after the lower frame assembly is mounted onto the undercarriage.

TECHNICAL FIELD

This invention relates generally to a main frame assembly for a tracked skid steer loader machine or multi-terrain loader machine and more particularly to such a machine having a main frame assembly, including a lower frame assembly capable of modular assembly with an undercarriage.

BACKGROUND

Skid steer loader machines are manufactured to provide a compact work machine that is maneuverable and durable in various applications. Skid steer loader machines are propelled by independently driven wheels on opposite sides of the vehicle that can be driven at different speeds and in different directions. Some skid steer loader machines use a loader body or lower frame assembly, in conjunction with a subframe or upper frame assembly, to define a main frame assembly for the loader machine. The lower frame assembly typically includes axle openings within which axles are disposed. The main frame may be assembled in a variety of ways to provide effective serviceability and durability.

Tracked skid steer loader machines or multi-terrain loader machines utilize an endless track undercarriage in place of the independently driven wheels to provide greater traction in mud, snow, ice and the like. An all-terrain vehicle is disclosed in U.S. Pat. No. 3,728,909 issued on Apr. 24, 1973 to Herbert A. Jesperson that is designed for high capability of travel over difficult and rough ground contours, conditions and textures. In particular, the Jesperson patent includes a body that has a center section with a bottom wall and front and rear walls extending from the bottom wall. Opposing side walls extending from the bottom wall and from the front and rear walls generally complete the center section. Located transversely on the underside of the bottom wall are a plurality of spaced parallel downwardly open channels which are formed in the continuous bottom wall surface. The channels cooperate with the track suspension group to permit modular assembly while, at the same time, affording maximum vertical clearance under the bottom wall and between the tracks, consistent with maintaining water-tight integrity of the body and maximum depth to afford sufficient space in the center section for the power group and the user's legs. In this regard, the track suspension group includes a frame having a plurality of structural cross members which are respectively and individually located in the respective downwardly open channels. The cross members are connected to the body by means in the form of plates which are welded to the cross members and adapted to span the ends of the channels and contact the exterior surface of the side margins around the channel ends. Screws or bolts are used to attach the plates to the side walls of the body. Although the open channels provide vertical clearance and depth, axial loads from the upper portion of the machine are directed on the screws or bolts attaching the cross members with the body. Therefore, such screws or bolts are likely to incur shear or torsional stresses that may damage or destroy the screws or bolts and, thereby, weaken the assembly. Further, the depth utilized to mount the cross members is not sufficient to lower the center of gravity of the machine to a maximum level.

The present invention is directed to overcoming the problems, as set forth above, by providing a structural design that enables a multi-terrain loader machine to be modularly assembled by mounting a solitary lower frame assembly or a fully assembled main frame to a pre-assembled undercarriage in a manner that distributes axial loading on the undercarriage.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a frame assembly for a loader machine is disclosed that has an undercarriage with at least one crossmember. The frame assembly comprises a main frame assembly with a base portion and front and rear sections. At least one recessed channel is defined on the base portion of the main frame assembly. The at least one recessed channel extends across at least a portion of the width of the base portion for seating upon the at least one crossmember.

In another aspect of the present invention, a frame assembly for a loader machine is disclosed with an undercarriage that has at least one crossmember. The frame assembly comprises a main frame assembly with a base portion and front and rear sections. At least one recessed opening is defined on the base portion of the main frame assembly. The at least one opening extends across at least a portion of the width of the base portion. The at least one opening is operably engagable with the at least one crossmember in a manner that distributes a vertical load of the loader machine substantially evenly along the at least one crossmember.

The present invention provides modular assembly of a main frame and an undercarriage. The modular assembly includes the use of at least one recessed opening defined in the main frame assembly that is seated upon at least one crossmember of the undercarriage. Such assembly provides external torsional strength and transverse support to the multi-terrain loader machine because the seating of the recessed opening on the crossmember evenly distributes the vertical load of the machine along the length of the crossmembers. Furthermore, because the recessed opening is seated on the crossmember, the machine's center of gravity is lowered to a maximum level, thereby resulting in additional machine stability.

DETAILED DESCRIPTION

While the invention described herein is susceptible to various modifications and alternative forms, one or more specific embodiments thereof have been shown solely by way of example in the drawings and are herein described in detail. It should be understood, however, that there is no intent to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

In the following description of the invention, an overview will be provided, followed by a description of the structure of the lower frame assembly. Then, a general description of the upper frame assembly will be disclosed. Further, a general explanation of the various modular assembly methods for mounting the main frame assembly to the undercarriage will be provided.

Overview of a Modularly Assembled Work Machine

Referring toFIG. 1, a loader machine1incorporating the features of the present invention and commonly known as a tracked skid steer loader or multi-terrain loader, is shown. Generally, the loader machine1has a front and rear end portion2,4. The loader machine1further includes a lower frame assembly6and an upper frame assembly8, which are mounted together to define a main frame assembly10, as further illustrated inFIG. 2.

The main frame assembly10is operable to be modularly assembled with an undercarriage12as shown inFIG. 1. Although the present invention is not limited to any specific undercarriage, a preferred embodiment of the undercarriage as depicted inFIG. 1and used herein for exemplary purposes, is a tracked undercarriage12. The tracked undercarriage12includes a right and a left track assembly13a,13b. As illustrated inFIG. 1, the track assemblies13a,13binclude a set of wheels14a,14b, driven by a drive16a,16b, and surrounded by a track17a,17b. Each drive16a,16btypically comprises one or more hydraulic motors (not shown) that are controlled to operate at multiple speeds and in a forward and reverse direction, thereby providing the capability for controlled skid steering capability. The track assemblies13a,13bare connected via front and rear crossmembers18a,18b. Crossmembers18a,18bare attached to plates19that are affixed to the track assemblies13a,13b, respectively, by bolts21.

The loader machine1is controlled by an operator (not shown) from within an operator's compartment22. Through a joystick device23, the operator (not shown) controls the loader machine1in a specific manner to achieve independent movement of the sets of wheels14a,14bwithin the right and left track assemblies13a,13b.

The Lower Frame Assembly

Referring toFIG. 2, a main frame assembly10with the upper frame assembly8and the lower frame assembly6according to the present invention is shown. The lower frame assembly6has a front end portion205and a rear end portion207and includes a pair of spaced, vertically oriented metallic side rails225,226that advantageously can be manufactured from a medium strength steel. The side rails225,226extend along the entire length of the lower frame6and have a plurality of mounting holes, an exemplary one of which is indicated by reference numeral227, configured to receive bolts228for attaching the upper frame assembly8to the lower frame assembly6. Each pair of side rails225,226has a front and rear end portion229,230, respectively, that defines the front and rear end portions229,230of the loader machine. A pair of recessed channels346,348, operable to receive the crossmembers18a,18b, respectively, of an undercarriage, as will be described below and shown best inFIG. 3, is located near the respective front and rear end portion229,230of the side rails225,226. Additionally, an intermediate portion231is disposed between the front and rear portions229,230of the side rails225,226.

At the front portion229of the side rails of the lower frame assembly6, a substantially vertical metal supporting wall234and an upper connecting wall236are joined to side rails225,226and, respectively, extend upwardly therefrom and therebetween. The upper connecting wall236adjoins a lower connecting wall237, preferably at an angle, as illustrated inFIG. 2, which also joins to side rails225,226. The upper and lower connecting walls236,237and supporting wall234define a front wall238of the loader machine. A pair of step assemblies239is attached to the supporting wall234.

Referring now toFIG. 3, the base or belly portion340of the lower frame assembly6is shown. Specifically, the base portion340of the lower frame assembly6includes three horizontally oriented protective plates341,342and343. A first horizontally oriented front protective plate341abuts the lower connecting wall237and extends rearwardly between the side rails225,226. It should be understood that the front protective plate341forms a front portion of the base or belly portion340of the loader machine. According to one embodiment of the present invention, the front protective plate341extends between and is welded to the side rails225,226. In a preferred embodiment, the front plate341is reinforced by front reinforcement strips,344a,344bwhich extend horizontally along the undersides of the front plate341, as shown in FIG.3. Preferably, the front reinforcement strips344a,344bare welded to the front protective plate341and to the respective side rails225,226.

The second horizontally oriented intermediate protective plate342is positioned between front and rear recessed channels346,348and also forms a portion of the bottom base or belly340of the lower frame assembly6. According to one embodiment, the intermediate protective plate342extends between and is welded to the side rails225,226. Preferably, the intermediate plate342is reinforced by intermediate reinforcement strips349a,349b, which extend horizontally along the undersides of the intermediate protective plate342, as shown inFIG. 3and which are preferably welded to the intermediate protective plate342and to the respective side rails225,226.

The intermediate protective plate342further contains a drainage opening (not shown), preferably positioned below the motor openings350and covered by a drainage panel351, as shown inFIG. 3. The drainage panel351is connected to the intermediate protective plate342and can be removed for draining hydraulic fluid.

The third horizontally oriented rear protective plate343extends rearwardly a predetermined distance from the rear recessed channel348. The rear protective plate343is positioned between and extends beyond the side rails225,226to define a rearward compartment. Preferably, the rear plate343is reinforced by rear reinforcement strips352a,352b, that extend horizontally along the undersides of the rear plate343, as shown inFIG. 3and which are preferably welded to the rear plate343. While the preferred embodiment has been described as using reinforcing strips, there are many alternative designs that can provide the desired strength to the structure, as would be known to one skilled in the art. Moreover, two or all of the front, intermediate and rear protective plates can be formed as a unitary structure from a single plate of metal, with recessed channels, formed by stamping and reinforcing as needed, or other methods in accordance with designs known in the art.

As depicted inFIG. 3, the front and a rear-recessed channel346,348extend transversely across the width of the lower frame base portion340. It should be noted that the recessed channels346,348may have any of a plurality of shapes for seating in mating relation upon the respective crossmember18a,18band may extend in a variety of ways transversely across the lower frame base portion340, each of such shapes and ways being within the scope of the present invention. For example, the loader machine1can foreseeably be manufactured using a single recessed channel.

Referring now toFIG. 4, the modular assembly of the recessed channels346,348of the lower frame assembly6onto the associated crossmembers of a tracked undercarriage12is shown. The channels346,348are recessed to receive the respective crossmembers18a,18b, as shown inFIG. 4. Advantageously, the recessed channels346,348permit the modular assembly of the main frame assembly10with the undercarriage12and increase the torsional stiffness of the lower frame assembly6resulting from the use of recessed channels346,348. First, for example, vertical and horizontal metal surfaces that form the recessed channel348will provide support that is not found where there is simply a flat plate as in a conventional design.

Second, in the assembled loader machine1, the surfaces of recessed channels346,348rest and are seated against the respective crossmembers18a,18band thereby increase the torsional support for the lower frame and maintain the machine's ground clearance while lowering its center of gravity. Conventional machine frames experience twisting when adverse terrain is encountered because the axles are mounted at the side corners of the machine, thereby providing torsional support only at machine corner locations, such as conventional tire locations. The present invention, however, structurally benefits from the recessed channels346,348because the recessed channels346,348provided added stiffness locally where the crossmembers18a,18bmount. Specifically, the crossmember bolts (or crossmember mounting holes) are located close to the recessed channels346,348on the side rails which adds to the stiffness and strength of the design.

Additionally, due to the recessed channels346,348of the present invention being seated on the crossmembers18a,18band the bolting of the crossmembers18a,18baround the respective channel346,348, as explained below, the loader machine loads are transmitted across the entire width of the loader machine1instead of at the bolting locations. In addition to providing torsional support, the recessed channels346,348result in a loader machine1with a lower center of gravity while maintaining conventional ground clearance distances. The lower center of gravity provided by the recessed channels346,348further improves overall stability of the loader machine1.

Furthermore, because the recessed channels346,348provide a strengthened belly structure, there is no need to affix a heavy strength steel plate over the protective plates341,342,343of the lower frame assembly6. Therefore, the lower frame assembly components may be formed of medium strength steel, due to the increased torsional stiffness of the lower frame assembly6provided by the strengthened area of the recessed channels. Manufacturing the lower frame components using medium strength steel can reduce the overall weight of the lower frame assembly6, despite the addition of additional material to form the channels. Moreover, using medium strength steel for lower frame components significantly reduces the manufacturing costs for the lower frame assembly6, due to the lower cost of the lighter steel.

Referring yet again toFIG. 3, motor openings350are formed in each of the side rails225,226of the lower frame assembly6for partially receiving hydraulic motors (not shown). Preferably, the motor openings350are positioned near the rear recessed channel348.

The Upper Frame Assembly

Referring now toFIG. 5, a perspective view of the upper frame assembly8and the lower frame assembly6, before being connected to form a main frame assembly10is shown. In particular, the upper frame assembly8has front and rear end portion554,555. A pair of spaced tower assemblies556,557are positioned near the rear portion555of the upper frame assembly8. According to one embodiment, each of the pair of tower assemblies556,557includes metallic inner and outer plates558,559. Preferably, the outer plates559are formed for welded connection with the inner plates558to define a spatial region560therebetween. More preferably, the inner plates558each have a contoured airflow defined therein. The inner and outer plates558,559each have a predetermined height and width. Preferably, each of the pair of tower assemblies556,557are rigidly supported by a plurality of metallic strengthening members welded between the inner and outer plates558,559, some of which are shown at561inFIG. 5.

A pair of metallic side members562,563extend along the entire length of the upper frame assembly8and have a shorter length than the length of the side rails225,226of the lower frame assembly6. Each one of the pair of side members562,563are connected to a respective tower assembly556,557by disposing a rear end portion564of the side members562,563within a portion of the spatial regions560. As indicated inFIG. 5, a front-end portion565of the side members562,563extends longitudinally from each pair of tower assemblies556,557. Each of the pair of side members562,563are formed to define a side wall666, as shown more clearly inFIG. 6, with a plurality of mounting holes (not shown) positioned along the length of the upper frame assembly8.

Referring now toFIG. 6, a side view of the main frame assembly10is shown. Specifically, an upper wall667of the side members562is substantially perpendicular to the side wall666and preferably includes a bent flange668which extends substantially along the length of the upper frame assembly8. The bent flange668has a mounting surface687substantially parallel with the side wall666and spaced therefrom.

Turning again toFIG. 5, each of the inner plates558of the pair of tower assemblies556,557is welded to the upper wall667of the respective side member562,563along a portion of the length thereof. Each of the outer plates559of the pair of tower assemblies556,557has a middle portion569which is connected to the bent flange668at the mounting surface687of the respective side member562,563along a portion of the length thereof.

A crossmember assembly572is connected between the pair of tower assemblies556,557and side members562,563. The crossmember assembly572is positioned between the front and rear end portions565,564of the side members562,563. The crossmember assembly572includes lower and upper crossmembers573,574, which are formed using metallic plates. The upper crossmember574also has an upper substantially planar surface575.

A frame structure588is partially defined by the inner plates558of the tower assemblies556,557and includes a cross plate589, which extends between the inner plates558. The upper and lower crossmembers574,573are welded to the frame structure588, along the cross plate589, for connection between the inner plates558.

The crossmember assembly572and the front end portions565of the side members562,563define an open access area590between the independent side members562,563, which is unobstructed by structural elements of the upper frame assembly8. The crossmember assembly572, the rear end portions564of the side members562,563, and the pair of tower assemblies556,557define an open service area591, which is separated from the open access area590by the crossmember assembly572. Further, the cross plate589defines an open region592between the upper and lower crossmembers574,573which provides access and air communication between the open access area590and open service area591.

A cab mounting structure of any suitable type is connected on each of the inner plates558of the tower assemblies556,557within the frame structure588at a juncture between the upper surface575of the upper crossmember574and the cross plate589.

A method for assembling the loader machine1of the present invention includes manufacturing the lower frame assembly6and upper frame assembly8as described above and shown inFIG. 1. Additionally, the lower frame assembly6and upper frame assembly8may further receive various sub-components prior to their being mounted together.

Modular Assembly of the Main Frame with the Undercarriage

Using the structure described above, specifically the recessed channels346,348and associated crossmembers18a,18b, the multi-terrain loader, and other machines, may be assembled to an undercarriage12using a variety of modular assembly methods. A preferred modular assembly method of the present invention, using the structures graphically illustrated inFIG. 4, is illustrated using the dashed line inFIG. 7. A second preferred modular assembly method of the present invention, using the structure graphically illustrated inFIG. 1, is illustrated by a solid line inFIG. 7.

A preferred modular manufacturing method, using the structure illustrated inFIG. 4, involves the mounting of a lower frame assembly6, having recessed channels346,348, onto the respective crossmembers18a,18bof an undercarriage12. In this particular embodiment, the modular assembly of a loader machine is manufactured from the bottom of the machine to the top of the machine. It is important to emphasize that the intermediate components utilized to build the loader machine, such as the lower frame assembly6, upper frame assembly8and undercarriage12, may all be pre-manufactured and inventoried, thereby requiring minimal process steps to build a complete skid steer loader.

As shown by the flowchart ofFIG. 7, the lower frame assembly, having a structure similar to that disclosed above, may initially be assembled or taken from inventory storage in step S1. Similarly, the undercarriage assembly, having a structure similar to that described above, may be modularly assembled or taken from inventory storage in step S5. The lower frame assembly may either be directly mounted to the undercarriage as in step S9or the upper frame assembly may first be mounted onto the lower frame assembly to create a main frame assembly as in step S7.

The dashed line inFIG. 7represents a modular assembly method wherein the lower frame assembly6is initially assembled or taken from industry storage in step S1and the undercarriage12is initially assembled or taken from inventory storage as in step S5, and the lower frame assembly is directly mounted onto the undercarriage in step S9. Specifically, the recessed channels of the lower frame assembly6accept the corresponding crossmembers18a,18bof the undercarriage12, thereby mounting the undercarriage12with the lower frame assembly6to create a base for building the loader machine1. In this regard, an upper frame assembly, having the structure described above, is either assembled directly onto the lower frame assembly/undercarriage or removed from inventory in step S3and bolted onto the side rails of the lower frame assembly to create a main frame assembly on an undercarriage at step S11. The main frame assembly is supplied with the sub-components, such as a cooling system and hydraulic pump assembly, as necessary to create a completed loader machine at step S10.

A second embodiment of a modular manufacturing method, using the structure illustrated inFIG. 1, involves the mounting of a fully assembled main frame assembly to a tracked undercarriage. Moreover, the solid line depicted inFIG. 7represents the corresponding manufacturing method using the structural design of the present invention. Specifically, the lower frame assembly and upper frame assembly are initially assembled or taken from inventory in step S1and S3respectively. The upper frame assembly is then-bolted onto the lower frame assembly to create a main frame assembly in step S7. The main frame assembly is then mounted onto the undercarriage in step S8wherein the recessed channels346,348of the newly created main frame assembly10are mounted over the corresponding crossmembers18a,18bof the undercarriage12. As necessary, sub-components are added to the lower frame assembly, upper frame assembly and main frame assembly, thereby resulting in a completed loader machine1in step S10.

INDUSTRIAL APPLICABILITY

The main frame assembly10, as described above, is operably configured to be modularly assembled using pre-assembled, intermediate components such as the lower frame assembly6, upper frame assembly8and undercarriage12. Although the features of the invention are demonstrated in the manufacture and assembly of a multi-terrain loader machine, it should be recognized that the recessed channels346,348may be utilized with a plurality of main frame assemblies10and undercarriages12having associated crossmembers18a,18b. The ability to manufacture various work machines, from a common lower frame assembly6, helps decrease manufacturing and assembly costs and increase production flexibility.

Further, the structure of the present invention allows intermediate components of the loader machine1, such as the lower frame assembly6, the upper frame assembly8and the undercarriage12, to be pre-manufactured and stored in inventory. The production of multiple loader machines, having a variety of main frame assemblies and undercarriages may be efficiently built by simply supplying the necessary components from inventory to the production line. Advantageously, the main frame assembly10and undercarriage12may be built at two different sites, for the sake of efficiency, and even modularly assembled at a third site. For example, modular assembly may enable a manufacturer to first mount only a lower frame assembly6onto the crossmembers18a,18bof the fully assembled undercarriage12and then, at the same or a different location, attach the upper frame assembly8to the lower frame assembly6, thereby providing a completed loader machine1.

Each recessed opening346,348is engagingly associated with a respective crossmember18a,18bof the pre-assembled undercarriage12, thereby allowing for the modular assembly of the loader machine1when the recessed openings346,348of the lower frame assembly6are mounted over the crossmembers18a,18bof the pre-assembled undercarriage12. Therefore, the recessed channels346,348and structure of the present invention allow for maximum component interchangeability, thus resulting in a more efficient manufacturing process. The detachable feature inherent in the structure of the present invention allows the loader machine1to be easily detached in order to ease care and maintenance of the machine parts.

Additionally, because the recessed channels346,348extend across the width of the base340of the lower frame6, the weight and axial loads of the loader machine1are evenly distributed along the crossmembers18a,18b. This structural advantage also increases the ground clearance of the loader machine1and lowers the machine's center of gravity, thus, resulting in increased torsional support, external torsion strength and overall machine stability.

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