WO2014056904A1

WO2014056904A1 - Subframe system

Info

Publication number: WO2014056904A1
Application number: PCT/EP2013/070934
Authority: WO
Inventors: Göran NORBERG
Original assignee: Ålö Aktiebolag
Priority date: 2012-10-08
Filing date: 2013-10-08
Publication date: 2014-04-17

Abstract

The present invention relates to a subframe system (20) for attaching a front loader (17) to a tractor chassis. The subframe system comprises: a first frame member (21) intended to be secured to the tractor chassis; and a second frame member (22) having a first (27) and a second end (28). The first end (27)of the second frame member (22) is stationary secured to the first frame member (21) and said second end (28) of the second frame member (22) comprises attachment means (30,31) for attaching the front loader (17) to the subframe system (20). The invention is characterised in that the first and / or second frame member comprises at least two attachment positions for the securing of the second frame member (22) to the first frame member (21).

Description

SUBFRAME SYSTEM

Field of the invention

The present invention relates to a subframe system for attaching a front loader to a tractor. Background of the invention

Within the agricultural field, tractors equipped with different types of working implements are frequently used in order to facilitate and speed up the work that needs to be done. A front loader, i.e. an elongated lifting arm, is attached to the tractor and extending in the forward direction of the tractor. In the forward end of the front end loader the implement, e.g. a bucket, guide rails, lifting forks etc is removably attached in order to be changeable to adapt the attached implement for the specific work that needs to be done, most frequently handling or moving objects or material.

Front loaders for agricultural tractors are usually not permanently attached to the tractor, as the user sometimes want to take it off while performing other work with the tractor. The front loader comprises two elongated loader arms, one on each side of the front end of the tractor, that are removably attached to corresponding subframes secured to the tractor chassis on each side of the front end of the tractor. The subframes are symmetrically arranged on the tractor. The subframes are normally bolted to the chassis of the tractor and comprise an interface for attachment of the front loader. The position of the subframe determines the attachment position of the loader on the tractor.

However, there is not one single attachment position of a front loader on a tractor that can be said to be the optimum. The preferred attachment position depends on several factors, for example, for some users it is very important to be able to open the front windscreen of the tractor which requires that the front loader is positioned more forward on the tractor and for other users it is desired to have the front loader positioned as far backwards as possible to improve the stability of the tractor when heavy loads are lifted. Furthermore, some users require a large front loader on the tractor in order to increase the lift height, while others prefer a smaller front loader that reduces the

obstruction of the visibility compared to a large front loader and If a small front loader would be attached to a subframe designed for a large front loader there is a risk that it would not extend all the way the ground if the size

difference is large.

The above described problems have until now been handled by offering a plurality of different subframes for each tractor to adapt the tractor for a specific front loader. This is not is a satisfying solution since the number of subframes makes it complicated to adapt the tractor for another front loader, and increases the cost for both manufacturing and maintenance of the

different components.

There is consequently a need for a more flexible subframe system that facilitates the attachment of differently sized front loaders to the tractor.

Summary of the invention

The subframe system for attaching a front loader to a tractor chassis according to the invention and defined in the independent claim provides a subframe system that fulfills the needs defined above.

The subframe system for attaching a front loader to a tractor chassis comprises: a first frame member intended to be secured to the tractor chassis; and a second frame member having a first and a second end, said first end of the second frame member is stationary secured to the first frame part and said second end of the second frame member comprises attachment means for attaching the front loader to the subframe system; wherein the first and / or second frame member comprises at least two attachment positions for the securing of the second frame member to the first frame member.

The claimed subframe system fulfills the needs by providing a flexible subframe system that makes it possible to adapt the attachment position of the front loader to meet the requirements from differently sized front loaders, working implements and the needs of different users. This is achieved since the subframe is divided into a first and a second frame member that could be secured at different position in relation to each other.

The subframe system consequently eliminates the need for additional subframes in different sizes in order to be able to fit different front loaders to the tractor.

In one embodiment of the subframe system, the first frame part is intended to be bolted to the tractor chassis and the second frame part extending upwards from the first frame part when the subframe system is arranged in the correct position on the tractor standing on substantially horizontal ground. This embodiment is favorable since the subframe system is flexible and makes it possible to achieve the desired spread of the attachment positions without compromising the structural strength of the subframe system.

In one embodiment of the subframe system, the attachment positions makes it possible to reposition the second frame member in relation to the first frame member along the horizontal and / or vertical direction of the tractor, and / or rotated around an horizontal transverse axis of the tractor. This embodiment makes it possible to further optimize the attachment position for the front loader since the position of the second frame member is adjustable in all required directions to meet the different needs of users within different parts of the world.

In one embodiment of the subframe system, the second frame part is secured to the first frame part by bolts extending through correspondingly arranged holes for each of the different attachment positions of the second frame member to the first frame member. This embodiment provides a very reliably and strong securing of the second frame member to the first frame member. The fact that more than one bolt is used increases the strength and prevents rotation of the second frame member in relation to the first frame member that might occur if one single bolt is used and the subframe exposed to high loads.

In one embodiment of the subframe system, the at least two of the attachment positions have at least one of the holes in common. This embodiment reduces the cost for producing the subframe system since the machining to achive holes with the desired accuracy are complicated and time consuming. Futhermore increased number of holes in the frame members will have a negative impact of the structural strengt of the member which could be a problem if exposed for high loads.

In one embodiment of the subframe system, the second frame member comprises at least two attachment positions arranged at different heights along the vertical direction. This embodiment makes it possible to adjust the attachment position of the front loader in vertical direction which is required when different sizes of front loaders are use.

In one embodiment of the subframe system, the first frame member comprises at least two attachment positions arranged at different positions along the horizontal direction. This embodiment makes it possible to adjust the attachment position of the front loader in the longitudinal direction which is favorable for example if the operator would like to open the front window of the tractor or increased space between the working implement and the front wheels is required to allow the wheels to be turned all the way to their end positions.

In one embodiment of the subframe system, at least one guiding spacer is arranged in a correspondingly shaped recess between the first and second frame member. The guiding spacer facilitates the repositioning of the first and second frame member and ensures the desired strength in the securing of the second frame member to the first frame member. Furthermore the guiding spacer in combination with the bolts for securing the members together prevents rotation between the first and second frame member and ensures rigid securing of the members.

In one embodiment of the subframe system, guiding means are arranged together with at least one of the bolts securing the second frame member to the first frame member. This embodiment facilitates the positioning of the first and second frame member during change of the attachment position.

In one embodiment of the subframe system, each guiding means comprises a female and a male part arranged together with the bolt. This embodiment of the guiding means provides the desired guidance during repositioning of the second frame member until the bolts are correctly arranged through the first and second frame member.

In one embodiment of the subframe system, the female and male part of the guiding means are integrated with the frame members during casting of the members and machined to the final shape. This embodiment is favorable since the female and male part of the guiding means could be manufactured together with the frame members which saves a considerably amount of time and work. In order to achieve the desired uniform quality of the female and male part that is necessary for precise positioning of the members the casted surfaces are machined.

In one embodiment of the subframe system, the holes in the first and second frame member are chamfered and an intermediate double cone arranged on the bolt between the first and second frame member. This embodiment provides excellent guidance during repositioning of the members and involves only one additional component, the double cone. The described embodiments of the arrangement could of course be combined in different ways without departing from the scope of the invention that is defined by the claims. The invention will be described more in detail in the detailed description.

Brief description of the drawings

Figure 1 illustrates a schematic side view of a tractor.

Figure 2a illustrates a side view of one embodiment of the subframe system according to the invention.

Figure 2b illustrates aside view of the first frame member of the subframe system.

Figure 3a illustrates a side view of the subframe in a first attachment

position.

Figure 3b illustrates a side view of the subframe in a second attachment position.

Figure 4a illustrates an alternative attachment position pattern.

Figure 4a illustrates a further alternative attachment position pattern.

Figure 5a illustrates a cross section of the guiding spacer and a bolt for securing the first and second member to each other.

Figure 5b illustrates a cross section of the dubbel cone spacer and a bolt for securing the first and second member to each other

Detailed description of embodiments

In figure 1 , a side view of a tractor 10 and selected components relating to the tractor are illustrated schematically. The tractor has a horizontal longitudinal axis A, a forward end 1 1 and a rear end 12. The tractor comprises a chassis, not illustrated in the figure, acting as the supporting framework for a number of different components in order to make the tractor work as intended. In this application only selected components of relevance for the understanding of the claimed invention of this application are disclosed in detail. The tractor is controlled by an operator normally seated within an operator housing 13 in the aft end of the tractor. The tractor comprises two forward wheels 14 that are turnable for steering of the tractor and two aft wheels 15. In the forward end an engine 16 and thereto related components for powering the tractor is arranged between the two forward wheels. On each side of tractor, between the forward and aft wheel, a subframe system 20 is secured to the chassis. The subframe system 20 comprises an attachment interface 21 for a front loader 17 extending from the subframe system in the forward direction of the tractor.

The front loader is movably attached to the subframe system and comprises two loader arms 18 attached on opposite sides of the forward end of the tractor. The two loader arms 18 are attached to the subframe systems arranged on each side of the forward end of the tractor.

The two loader arms 18 have similar configuration and consist of a forward arm section 19a and en aft arm section 19b arranged at an angle of about 120° to each other such that the forward arm section is extending more downwards than the aft arm section. The design of the loader arms could however be modified in several ways in order to adapt the front loader to perform the desired work in the best way possible. These modifications could for example involve adjustment of the length of each of the forward and aft arm sections or the angle between the two sections. In the forward end of the front loader a working implement 8 is removably attached to the front loader. In figure 1 , the implement is a bucket and the tractor furthermore comprises means 6 for lifting and lowering the front loader, and means 4 for controlling and moving the working implement. The lifting and lowering of the front loader as well as the movements of the working implement are normally achieved by a number of hydraulic cylinders arranged at suitable positions on the tractor and the loader arm in order for them to generate the desired movements of the loader arms and the working implement. In figure 2 the front loader is illustrated in two different positions, a first position P1 where the bucket is on the ground and a second position P2 located at the maximum height possible. However, for example en electrically powered system could also be used in order to generate the desired movements of the front loader and the implement.

Figure 2a illustrates a perspective view of the subframe system 20 according to the invention. One subframe system 20 is arranged on each side of the tractor in order to secure the two loader arms of the front loader to the tractor. The two subframe systems have similar configuration but are adapted to be fitted on the opposite sides of the tractor.

The subframe system 20 comprises a first frame member 21 and a second frame member 22. The first frame member, illustrated in figure 2b, is intended to be fitted on the left side of the tractor and extending in the longitudinal direction of the tractor. The first frame member has a first 23 and a second end 24. The first end is intended to be arranged towards the forward end of the tractor and the second end towards the aft. The first frame member is intended to be rigidly secured to the tractor chassis and comprises a number of holes 4 arranged in the forward 23 and aft end 24 for bolts 25 intended to extend through the first frame member and corresponding holes in the tractor chassis to secure the first frame member. The first frame member 21 is formed of a plate with substantially constant thickness and the first 23 and second end 24 of the central section are substantially flat and intended to rest against a vertical side surface of the chassis prepared for securing of the subframe system. The design of the first frame member could however be modified in several ways in order to be adapted to different tractor chassis and ensure the desired strength and rigidity of the subframe securing in the chassis. The area available along the tractor chassis for attachment of the subframe is limited and must be carefully considered when the first frame member is designed. The illustrated embodiment of the first frame member is curved along the longitudinal direction and the central section 26 of the first frame member arranged at a distance from the chassis. The plane of the central section is substantially parallel to the plane of the first and second end and a gap between the side surface of the central section facing the chassis and the chassis is thereby created. This gap is required to facilitate the securing the second frame 22 to the first frame member 21 which will be described more in detail further down this description.

Outside first frame member 21 , in the direction from the tractor, the second frame member 22 is arranged. The second frame member 22 is extending in a plane substantially vertical and parallel to the plane of the central section 26 of the first frame member 21 , as well as the longitudinal axis A of the tractor 10. The second frame member 22 has a first 27 and a second end 28. The first end 27 is arranged adjacent the outside surface of the central section 26 of the first frame member 21 and the second frame member extending substantially vertically upwards from the first frame member 21 . The second frame member consist of a first 45 and a second plate 46 permanently secured together to increase the strength of the member. The first plate 45 is arranged adjacent to the first frame member 21 and the second plate 46 substantially parallel outside the first plate 45.

The frame members are either manufactured by cutting the member out of a plate of a metallic material with the desired properties such as thickness, stiffness and strength. The cut out member could furthermore be bent to the desired shape if a curved member is desired. Alternatively, the members are casted in a mould to the desired shape and selected surfaces machined to the desired finish or shape. The favored alternative of the different methods depends on the design of the member and the expected loads that the subframe system will be exposed to. For example, if the members have a complex three dimensional design the casting method is the preferred alternative in order to reduce the time spent to achieve the desired shape, and if a substantially flat, plate-like member is desired the member is cut out of a plate to the desired shape. Furthermore each of the members could be made of several pieces that are secured together, for example by welding.

The upper second end 28 of the second frame member 22 comprises attachment means 29 configured to make it possible to removably attach one of the loader arms 18 of the front loader 17 to the tractor. In the illustrated embodiment the attachment means comprises a cut out portion 30 and locking means 31 . The attachment means 30 and the locking means 31 prevent unintended release of the front loader could be modified in several ways and does not form part of the claimed invention.

The claimed invention is directed to the flexible securing of the second frame member 22 to the first frame member 21 that makes it possible to adjust the position of the second end 28 of the second frame member 22 in relation to the tractor 10 and thereby adapt the subframe system to different types and sizes of front loaders.

In the illustrated embodiment, the first subframe member 21 comprises three holes 32 arranged in the central section 26 in a predetermined pattern. The second frame member 22 comprises an equal amount of holes 33 arranged in a corresponding pattern in the first end of the second frame member 22. In two of these three holes, bolts 34 are arranged to secure the two members together. The fact that corresponding predetermined pattern is provided in each of the members 21 and 22 makes it possible to adjust the vertical height of the attachment position for the second frame member 22 by selecting another combination of holes 32, 33 in respective frame member 21 , 22.

To assist the positioning of the frame members during mounting, each of the holes 32 in the first frame member is provided with a cone-shaped guide 35 (male) that extend from the surface of the first frame member 21 towards the second frame member 22 that is provided with a correspondingly shaped conical (female) recess 36 around the hole 33. When fitted together, the cone-shaped guides 35 in combination with the cone-shaped recesses 36 will assist correct positioning of the frame members which is necessary in order to be able to fit the bolts 34 in the holes 32, 33 of the two members and finally secure the members 21 , 22 together.

From the outside surface of the central section 26 of the first frame member 21 a spacer 37 protrudes towards the second frame member 22. The spacer 37 is arranged below the holes 32 previously described and the outer end of the spacer 37 will be in contact with the adjacent surface of the second frame member in order to support and arrange the second member in the intended angle in relation to the first frame member since the height of the spacer, i.e. the distance from the surface of the first frame member to the top of the spacer 37, will determine the direction that the second frame member is extending in. The spacer is in the illustrated embodiment provided with a passage 38 extending through the spacer and the first and second member comprises corresponding holes for a further bolt 39 fitted trough the members and the spacer.

Figure 2a and 2b discloses one embodiment of the attachment positions in the frame members 21 , 22 of the subframe system 20 but the pattern of the holes 32, 33, the number of the holes 32, 33 the design of the male and female guides could be modified in several different ways in order to adapt the subframe system for different purposes. In figure 3a and 3b, the two different attachment positions of the second frame member to the first frame member that are possible are illustrated. As can be seen in the figures the vertical position of the second frame member is lower in the fig 3b than in figure 3a. Furthermore the second frame member is extending in a slightly different angle from the first frame member.

In figure 4a and 4b, two different embodiments of bolt patterns that could be used in order to satisfy the needs for adjustment are illustrated. The bolt pattern is either arranged in the first or the second frame member,

alternatively in both members depending on the specific needs.

The pattern illustrated in figure 4a comprises two different attachment positions. The two attachment positions A1 and A2 are arranged at different longitudinal (ΔΙ) and vertical positions (Ah) as well as slightly rotated (Δα) in relation to each other which mean that the second frame member will extend in different directions from the first frame member. The pattern illustrated in figure 4b comprises a matrix with three columns and three rows. The size of the matrix could however be modified in any possible way to satisfy the needs for adjustment. This embodiment provides a very flexible subframe system since a number of different attachment positions are generated within the matrix.

In figure 5a, the male / female guide used for positioning of the two frame members is illustrated in an enlarged view. In this embodiment a guide 40 is permanently secured, for example by welding, in the hole 32 in the first frame member 21 . The guide 40 comprises a centrally arranged opening 41 and a tapered recess 42 (female) that is facing the second frame member 22. The second frame member comprises the corresponding hole 33 in which a guiding cone 43 (male) is permanently secured. When the first and second frame member are correctly positioned, the guiding cone 43 fit in the tapered recess 42 and the position of the frame members 21 , 22 is locked until the bolts 34 have been tightened to rigidly secure the second frame member 22 to the first frame member 21 and the tractor chassis. Obviously the position of the female and male guide could also be switched.

In figure 5b, another embodiment of a male / female guide arrangement is illustrated in an enlarged view. In this embodiment a separate guide 50 is arranged on the bolt 54 between the first and second frame member. The first and the second frame member both have holes 51 with a tapered shape 52 extending from surfaces of respective member that are facing each other such that a recess 53 for the separate guide 50 is formed between the two frame members 21 , 22. The guide 50 has the shape of a double cone and assists during the positioning of the second frame member 50 and could either be permanently secured in one of the members or held in the intended position by the bolt 54 that is fitted through the first and second member and the guide 50. The shape of the separate guide 50 could be modified in several ways as long as the shape of the recess 53 formed between the members corresponds to the shape of the guide.

A further embodiment, not illustrated in the figures, comprises male / female guides working in the same way as the one described above but arranged separated from the bolts 34, 54. These guides assist the positioning of the members in the same way as described above but are arranged separated from the bolts.

In a further embodiment, not illustrated in the drawings, the female and male parts of the guiding means are provided as integrate parts of the frame members during casting of the members. This embodiment reduces the cost for the subframe system, especially if the numbers of guiding means are high. In order to achieve the desired shape of the female and male part of the guiding means as well as uniform quality of the female and male parts they are machined to the desired shape and surface roughness. The guides could furthermore be designed to work as spacers that prevent contact between the surfaces of the first 21 and the second frame member 22. This is illustrated in figures 5a and 5b, where the dimensions of the guides ensure that the members will be separated even after the bolts have been tightened. The different embodiments described above could all be combined and modified in different ways without departing from the scope of the invention that is defined by the appended claims.

Claims

A Subframe system (20) for attaching a front loader (17) to a tractor chassis, said subframe system comprising:

a first frame member (21 ) intended to be secured to the tractor chassis; and

a second frame member (22) having a first (27) and a second end (28), said first end of the second frame member is stationary secured to the first frame member (21 ) and said second end of the second frame member comprises attachment means for attaching the front loader to the subframe system; wherein

the first and / or second frame member comprises at least two attachment positions for the securing of the second frame member to the first frame member.

The subframe system according to claim 1 , wherein the first frame member is intended to be bolted to the tractor chassis and the second frame part extending upwards from the first frame member when the subframe system is arranged in the correct position on the chassis of the tractor standing on substantially horizontal ground.

The subframe system according to claim 2, wherein the attachment positions makes it possible to reposition the second frame member in relation to the first frame member along the horizontal and / or vertical direction of the tractor, and / or rotated around an horizontal transverse axis of the tractor.

The subframe system according to anyone of the previous claims, , wherein the second frame member is secured to the first frame member by bolts (34) extending through correspondingly arranged holes (32, 33) for each of the different attachment positions of the second frame member to the first frame member.

5. The subframe system according to claim 4, wherein at least two of the attachment positions have at least one of the holes (32, 33) in common.

The subframe system according to claim 3, wherein the second frame member comprises at least two attachment positions arranged at different heights along the vertical direction.

The subframe system according to claim 3 or 6, wherein the first frame member comprises at least two attachment positions arranged at different positions along the horizontal direction.

The subframe system according to anyone of the previous claims, wherein at least one guiding spacer (50) is arranged in a

correspondingly shaped recess (53) between the first and second frame member.

The subframe system according to anyone of the previous claims, wherein guiding means (40, 43) are arranged together with at least one of the bolts (34) securing the second frame member to the first frame member.

10. The subframe system according to claim 9, wherein the guiding means comprises a female (42) and a male part (43) arranged together with the bolt (34).

1 1 .The subframe system according to claim 10, wherein the female and male part of the guiding means are integrated with the frame members during casting of the members and machined to the final shape.

12. The subframe system according to claim 9, wherein the sides of the holes (51 ) in the first and second frame member are chamfered (52) and an internnediate double cone (50) arranged on the bolt (54) between the first and second frame member.