JPH0626068A - Vertical lifting loader boom device - Google Patents

Abstract

(57) [Summary] [Purpose] After the lift arm reaches the selected lift height, the main lift arm can be moved along a substantially vertical trajectory to improve the forward reach of the boom assembly at high lift positions. To do. [Structure] The loader boom assembly 10 is a joint lift arm including a first lift arm portion 28 and a second lift arm portion 26 that are rotatably attached. The rear lift arm portion 32 is rotatably attached to the rear portion of the frame 14 of the prime mover. The main lift arm portion 30 is substantially longer than the second lift arm portion 28, and is pivotally supported by the outer peripheral end portion of the rear lift arm link 32. Lift arm link part 2
Reference numerals 6 and 28 are the folded postures when the lift arm is in the lowered position. As the lift arm is lifted, the lift arm is extended by the control link 66.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention provides a substantially vertical linear track throughout substantially the entire upstroke of a boom assembly.
The present invention relates to a loader boom assembly for a self-propelled loader that is controlled to maintain the tip of the boom assembly.

[0002]

2. Description of the Prior Art Loader boom assemblies have been used to provide substantially vertical movement of buckets for lifting material. For example, U.S. Pat. No. 4,355,946 uses a long lift arm support link at the rear of the loader boom assembly to improve the front bucket lift trajectory and level the bucket. A link mechanism for controlling a lift arm of the loader is described.

Hall, US Pat. No. 3,215,292, issued Nov. 2, 1965, describes a guide link that operates to extend a lift arm of a loader as it is raised.

[0004]

However, in the above-mentioned conventional device, when the bucket is raised, in the upper part of its operating range, the bucket does not move along a substantially vertical trajectory but rather moves outside the supporting device. Moves continuously towards.

[0005]

SUMMARY OF THE INVENTION The present invention includes a pair of lift arms, each lift arm having a lift arm that is lifted from a horizontal position as the lift arm is lifted. A boom assembly for a loader including a pair of articulated links operatively controlled to move an outer end thereof in a generally vertical and substantially linear manner. The articulation link of each lift arm is the main lift arm link that extends forward, that is, the main lift arm portion,
And a rear, substantially short lift arm link, i.e., having one end pivotally supported with respect to said main lift arm link or main lift arm portion and the other end pivotally supported with respect to the frame of the self-propelled loader. Includes lift arm section.

[0006]

[Operation] The movement trajectory of the main lift arm part is partially
It is controlled by a control link connected to the tip of the frame of the self-propelled loader and the main part of each lift arm. The lift arm is lifted by the operation of a fluid pressure cylinder or actuator in which a repulsive force acts between the main lift arm section and the main frame of the loader. As the boom assembly is lifted, the rear lift arm link is first controlled to pivot about its pivot on the loader main frame and the other end of the rear link pivotally supported relative to the main lift arm link. That is, the first end is controlled by the control link to pivot rearward. After the bucket at the tip of the boom assembly approaches the height of the pivot of the rear lift arm link with respect to the main frame of the loader, one end of the rear lift arm section or link lifts the boom assembly further up. As it starts moving forward, the main lift arm also moves forward. As a result, the rear and main lift arm links, or main lift arm sections, expand as the boom assembly rises, and through the entire upper operating range of the lift arms that form the boom assembly, the lift arm tips and buckets. Keeps an almost vertical orbit moving.

Thus, the bucket support at the tip of the lift arm is positioned to facilitate the unloading of material onto, for example, the truck, and the tip of the lift arm arcs in the upper portion of the lift arm's upward movement. It has the advantage that it does not move backwards.

Both parts of each loader lift arm, the hydraulic actuator, and the control links of each lift arm are assembled so that they are in a common plane, so that the lateral dimension of the driver's seat has a conventional boom. No changes need to be made to the current dimensions of skid steerloaders.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A loader assembly (generally designated 10) made in accordance with the present invention is mounted to a skid maneuver or prime mover 12. The prime mover 12 has a main frame 14 extending over the entire front-rear direction, and is appropriately supported on front and rear wheels 16. Wheels 16
Engine room 1 just behind the driver's seat 18
It is driven by an engine (not shown) in 5 in a suitable manner via a drive system supported on the main frame 14. A frame-shaped upright member 20 at the rear of the main frame is used to support the loader 10. Each upright member 20 consists of plates spaced apart and separately. It is well known that the outer tip moves in an arc when a conventional loader boom mounted to the loader frame by a single pivot moves up and down. And when the boom begins to rise, the supported bucket moves some forward, and after the pivotally supported boom crosses the center point, the bucket moves upwards and only a significant amount. There is a tendency to move backwards and, as a result, to reduce the forward travel of the boom assembly bucket in the raised position.

The main frame 14, frame-shaped uprights 20, drive wheel arrangement, fender 22, and wide driver's seat 18 all feature standard skid steer loading equipment.
The driver's seat extends laterally across the entire main frame. The driver's seat extends almost the entire width between the plate inside the frame-shaped upright member 20 and the fender 22 (see FIG. 4). The articulated boom of the present invention is designed to match the basic structure of the main frame, and the wide, upright driver's seat allows normal entry for conventional machine maintenance. The engine compartment 15 is just behind the driver's seat 18, and the engine handling door or panel 15A is unobstructed by the rear link 32 and uses the pivot 40 at a high position so that the transverse member There is clearance from 36 and it can be opened like existing machines.

For the purpose of utilizing the conventional, basic arcuate boom loader design of the boom, the rear pivot in the high position remained the conventional device.

The general form of skid steer loader shown here is well known and is manufactured by Merlot Company, an affiliate of Clark Equipment Company of Fargo, North Dakota, and is Bobcat "BOBC".
It is on the market under the registered trademark "AT".

In this embodiment, the loader 10 has a lift boom assembly 24 consisting of two partial booms. The two partial booms consist of a main lift arm assembly 26 and a rear lift arm link assembly 28 that are pivotally mounted to each other. Main lift arm assembly 2
6 comprises a pair of main lift arm links or main lift arm portions 30 and a pair of rear or second lift arm links or second lift arm portions 32 which are laterally spaced apart. The main lift arm links 30 are on both sides of the main frame and their tips are, for example, transverse members 34.
Are connected by suitable transverse members such as. And
Spaced rear lift arm links 32 are on opposite sides of the main frame and are joined together by suitable lateral members 36. The main lift arm assembly 26 has a leading end and a trailing end, with the main lifting arm portion having a suitable pivot pin 38 at its trailing end.
Each of which is pivotally coupled to form a pivot with the first end of the rear lift arm link 32. Main lift arm section 30 and rear lift arm link 32
Are coupled so that they lie in a common plane along the side of the driver's seat.

Further, each rear lift arm link 32 is provided.
Are suitable pins that form a pivot for each of the frame-shaped upright members 20 between the plates forming the respective frame-shaped uprights, proximate the rear portion of the main frame 14 and above the uprights. It is rotatably connected to 40. The axis of the pin 40 forming the pivot of the rear lift arm link assembly is
It has been raised to a considerable height from a support surface generally indicated at 42. The main lift arm link 30 has a forearm 44 extending downward. The front arm 44 extends downward and forward just in front of the front wheels 16 when the lift boom assembly 24 is in the lowered position. At the tip of the main lift arm portion 30, there is a mounting pin 46 that forms a pivot for supporting the work implement. The working tool is a bucket 48 supported by an auxiliary frame 50, as shown in the figure. The auxiliary frame 50 is pivotally attached to the pin 46 and is controlled by a tilting cylinder or actuator 52 by a known method. Tilt cylinder 52
Is connected at its proximal end to a support member 53 mounted on the lateral member 34. The auxiliary frame 50 is a mounting frame sold under the registered trademark of Bob Touch "BOB-TACH" by Merlot Company, an affiliate of Clark Equipment Company in Fargo, North Dakota. Of course, any other desired attachment for the work implement or bucket 48 could be used. In many cases, the pin 46 used to determine the path of travel of the tip of the main lift arm 30 during the lifting operation.
Of the axis, or the front edge of the bucket 48, is a defined point.

In this embodiment, a control arm 54 is fixed to the main lift arm portion, that is, the link 30, at a position spaced from the pivot 38 in the front direction. Control arm 54
Is made of two spaced plates and extends downward along both sides of the driver's seat 18 to a position just above the ender 22, as can be seen. The hydraulic actuator or cylinder mounting plate portion 56 is secured in a suitable manner to the main lift arm portion 30 on each side of the boom assembly. The mounting plate portion 56 is provided on the control arm 54.
It may be a part of the plate constituting the.

Separate double acting hydraulic actuators or cylinder assemblies 58 are mounted on opposite sides of the main frame and have extendable and retractable rods. The rod has rod ends which are joined by suitable pins 60 between spaced plates 56. The proximal end of each actuator or cylinder 58 is located between the plates forming the uprights 20 which are connected to the main frame 14 by suitable pins 62, as shown. The proximal pin 62 for the double acting hydraulic actuator or cylinder 58 is
Note that it is well below. The actuator extends forward and upward from the pivots 62 to 60.

In the present embodiment, the control link is a fixed length or fixed link, generally designated 66. Fixed control links are located on opposite sides of the main frame 14 and, thus, a separate control arm 66 is provided for each lift arm of the boom assembly.
Each link 66 is fixed to the main frame 14 of the prime mover 12 by having a tip end portion pivotably fixed to a fixing bracket on each fender 22 with an appropriate pin 68. The other end of the fixed link 66 is connected to each control arm 54 of each main lift arm portion 30 by a suitable pin 70 and is located between the plates forming each control arm 54.

In its lowered position, each link 66 is substantially horizontal to the boom assembly 24. When working with a bucket or the like, there is a rearward force when the bucket is under load. The horizontal link 66 is
Substantially parallel to the direction of the rearward force, it acts to withstand the rearward movement of the individual main lift arm sections 30 and rear lift arm links 32. Of course, a part of the load to the rear is passed through the pin 38 and the rear lift link arm 32, and further the pivot 40 of the frame-shaped upright member 20.
Is also transmitted. However, for a joint lift arm in which the two lift arms are pivotally supported with respect to each other, the horizontal load vector acting rearward on the pin 46 is avoided to avoid the main lift arm 30 and the rear lift arm link. Tends to fold. Link 66, actuator 58, main lift arm section 30,
And the links on both sides of the rear lift arm or boom assembly save space in the lateral direction for existing skid controls without reducing the width of the driver's seat or increasing the overall width of the device. For matching, they are arranged in a common plane.

Actuator or cylinder assembly 58
Is operable to lift the boom assembly 24 to a high unloading position using a valve and a source of fluid pressure (not shown). When the boom assembly is lifted, the pin 46 axis, or bucket tip, describes a generally vertical trajectory throughout the upper portion of the working range used to unload the bucket. FIG. 1 shows the boom assembly 24 in the lowered position.
Indicates. In FIG. 3 showing the movement trajectory of the pin 46, after the pin 46 reaches almost the same height as the pin 40 on the support surface 42 (shown by the horizontal chain line in FIG. 3), the lift arm Is further lifted,
Instead of moving in an arc backwards, the axis of the pin 46 moves almost vertically to the maximum lift position of the lift arm. The tilting cylinder 52 can be operated as desired by conventional means to tilt the auxiliary frame 50 and the bucket 48 about the axis of the pin 46. as a result,
No matter what particular tilting position the bucket 48 has,
Each point on the bucket, such as its leading edge, will move along a trajectory that corresponds to the trajectory of the axis of the pin 46.

In the lowered position of the boom assembly 24, the main lift arm section or link 30 and the rear lift arm section or link 32 on either side of the loader are aligned with the center line of the rear link 32, the axis of the pivot pins 38 and 40. And the line connecting the pivot pins 38 and 46 forms an included angle. This included angle is represented by a double arrow 74. When the lift cylinder or actuator 58 is actuated to initiate lifting of the boom assembly 24 or bucket 48, a fixed link 66 that pivots upwardly around a pin 68 forces the rear lift arm link 32. The included angle 74 first decreases as it is moved rearwardly.

The control arm 54 positions the pivot pin 70 at the rear end of the link 66 in position so that the lift arm link 32 moves rearward as the arm pivots. The pin 46 then rises along a track 47 as shown in FIG. 3 and when the boom assembly 24 extends the cylinder or actuator 58 to a position where it moves about one-third of its entire upward stroke, the included angle 74. The reduction of the stops.
Then, when the two lift arm portions including the main lift arm portion or the link 30 and the rear lift arm portion or the link 32 are expanded as the end portion of the link 66 moves forward in an arc, the included angle 74 is increased. Begins to grow again. Boom assembly 2 from pivot pin 40 to front end
The effective length of 4 increases in the upper two-thirds of its ascending stroke, thus moving the pin 46 and the relevant part of the bucket along a vertical trajectory. Thus, the fixed control link 66 controls the pivoting movement of the pivot pin 38 as the lift arm link 32 pivots about the pin 40. Having the link 66 have a substantial length (ie, about twice the length of the rear lift arm link 32), and setting the rear lift arm link 32 substantially shorter than the lift arm link or lift arm section 30. By appropriately selecting the size and the positional relationship (geometrical relationship) of the link including the above, the movement trajectory of the pin 46 and the bucket 48 can be made as desired.

Since the length of the control link 66 is fixed, when the lift arm is lowered, the same movement track is followed. This boom assembly maintains the advantages of the high position swing boom point 40 of existing skid steer loaders with improved lifting capacity, and the advantage of having a small loader that can be steered similar to conventional skid steer loaders. However, in the upper part of the movement track of the boom assembly, the purpose of obtaining a longer movement distance (reach) is achieved,
Therefore, it facilitates unloading of trucks and stacking to high positions.

The plane defined by pins 68 and 70 is the pin 6 of the lift cylinder or actuator 58.
2 above and with the pin 70 behind the pin 68, the pin 70 moves upwards and forwards from the position where the boom is lowered and the link 66 is substantially horizontal, causing the rear link 32 to initially move backwards. Move to. The axis of pin 70 is pin 6
Across the plane defined by the 8 and 38 axes, as the pin 70 rises, the overcenter "overce
In the selected lifting position of the main lift arm part, when the main lift arm part is further lifted, the fixed link 66 starts moving the rear part, that is, the second lift arm link forward, and again the pinching. Begin to increase corner 74. Main lift arm or link 30.
And the effective length of the boom assembly consisting of the rear lift arm links 32 increases as long as the lift continues.

It should be noted that the link 66 is made adjustable in its length in order to adapt to the individual requirements of the motion trajectory and for the control of the different trajectories of the pins 46. is there. However, the link structure shown here provides the desired vertical motion trajectory of the pin 46 when the bucket is lifted to the desired height. In other words, after reaching the desired height near the pivotal height of the pin 40, the bucket is lifted along a generally vertical trajectory.

A loader assembly mounted on a high pivot and equipped with a short rear lift link arm improves the rigidity of the lift boom assembly 24 and limits the margins reserved along both sides of the driver's seat. The lift arm moves along the track. The rear lift arm link 32 attached to the frame-shaped upright member 20 by the high position pivot shaft 40 can enjoy the advantages of the articulated boom without extending to the space necessary for opening the rear engine room. (EN) Provided is a boom assembly which has good access to a room for maintenance. The boom assembly consists of the rear entrance door 1 of the engine room 15.
It does not extend backwards beyond 5A. The articulated boom loader of the present invention has a considerable degree of commonality with conventional skid steer loaders in terms of basic frame and drive construction.

The movement paths of the bucket 48 and the tip of the lift arm are, as described above, the rear lift arm link 3.
2 is guided by the fixed link 66, and moves backward in the initial lifting position. This initially tends to move the bucket in a more vertical trajectory, so that when the bucket is first lifted, it causes the bucket 48 and its load to move outward on the radius of gyration rather than forward. Keep it close to 14 and. Therefore, the rearward movement of the rear lift arm link is
It is an important feature in determining the initial lifting trajectory of a bucket.

[0027]

The present invention provides a vertical lifting track in the operating range of a loader boom where normally boom reach is reduced. As a result, the operation of the loader for loading onto the truck or loading the material can be more easily advanced. The control linkage provides reliable and reliable control to obtain a vertical motion trajectory.

The present invention allows for a vertical lifting trajectory in the operating range of a boom system which would normally have increased boom reach, ie, a radius of rotation arc that would move forward.

In this mechanical linkage system, both the initial inward movement and the increased reach near the maximum lift position can be combined in a conventional skid control design. As a result, the existing features of the device design, manufacturing method, driver's seat, operating unit, engine,
Maintenance work in the areas of transmissions, fluid and hydrostatics, cooling systems, electrical systems, access features for maintenance and means of attachment of accessory work tools to skid controls can be maintained.

Although the present invention has been described with reference to the preferred embodiments, it will be apparent to those skilled in the art that modifications in shape and detail can be made without departing from the spirit and scope of the invention. .

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing a skid steer loader equipped with a loader boom assembly of the present invention.

FIG. 2 is a side view of the loader shown in FIG. 1 when viewed from the opposite side.

FIG. 3 is a partial schematic side view illustrating the bucket and boom assembly in a plurality of lifting positions to show the trajectories of the outer ends of the boom assembly and the supported bucket.

FIG. 4 is a perspective view of the loader boom assembly of the skid steer loader shown in FIG. 1 shown with a flat frame with other portions removed for clarity.

[Explanation of symbols]

14 ... Main frame, 20 ... Frame-shaped upright member, 30 ... Main lift arm link, 32 ... Rear lift arm link, 4
8 ... Bucket, 54 ... Control arm, 58 ... Fluid pressure cylinder, 66 ... Fixed link

Continuation of front page (72) Inventor Orlan Jay. Loras Elm Street, Lisbon, 58054 North Dakota, USA 912 (72) Inventor Wally El. Katimarusky 58054 North Dakota, Lisbon, Route 3, Box 105 (72) Inventor Larry E. Albright Maplewood Drive 162, Guiner, 58040 North Dakota, United States

Claims (16)

[Claims] 1. A loader lift boom assembly provided on a prime mover, comprising a longitudinal main frame having a boom support member fixedly attached to a rear portion thereof, wherein the boom support member has an upper end portion. A pair of lift arms are disposed on both sides of the frame and are coupled together to operate as a lift arm assembly, the lift arm assembly having a tip mounting member for mounting a work implement and a rear end; Each of the pair of lift arms includes a main lift arm link extending rearward from a front portion of the frame, a first end portion pivotally mounted on a rear end of the main lift arm link, and a support plane of the main frame. A second lift arm link having a second end pivotally mounted to an upper end of the boom support member and further below the main lift arm link. And a second joint lift arm link, a telescopic power actuator means having a first end pivotably attached to the main frame extends forward and upward, and each is connected to the main lift arm link. A second lift coupled to the at least one main lift arm link so as to control a motion trajectory of a pivot between the main lift arm link and each second lift arm link when the lift arm is raised and lowered. A control link having a longer length than an arm link, wherein the control link is pivotally mounted on a main frame near a front part of the main frame and pivotably attached to a main lift arm link extending rearward. A second end mounted, and wherein the control link is configured to pivot from the pivot support member of the actuator means relative to the main frame when the lift arm is in the lowered position. The second lift arm link is positioned below the pivot support means such that the second pivot axis of the control link moves in an arc as the lift arm assembly is lifted by the actuator means, and the boom assembly When the solid is lifted to a desired position, the pivot connecting each main lift arm link and its respective second link is such that the total length of the two lift arm links of each lift arm is effectively shortened and extended, Lift boom device characterized by moving in a controlled orbit. 2. When the main lift arm link is in the lowered position, each second lift arm link extends forward and upward from its pivot for the upright support member toward its pivot for the main lift arm link. By pivoting the lift arm link backwards, when the main lift arm link is lifted,
Initially the first included angle is reduced by the control of the control link,
A desired position for the pivot of the second end of the control link to pass through a plane defined by the pivots provided at the second end of the second link and the first end of the control link. The lift boom device according to claim 1, wherein the first included angle is increased after the lift arm assembly is lifted up to the end. 3. The control link is rotatably attached to the main lift arm link via a second arm fixed to the main lift arm link, and a pivot point connecting the control link and the main lift arm link is a lift arm. 2. The lift boom apparatus according to claim 1, wherein the lift boom apparatus is arranged so as to be shifted substantially downwardly from a pivot coupling portion connecting the main lift arm link and the second link provided on both sides of the assembly. 4. The main lift arm link and the second lift arm link are in a folded position when the main lift arm link is in the lowered position, the control link is substantially longer than the second lift arm link, and the actuator is As the main lift arm link is moved upwards by the means, the main and second lift arm links are first folded together and then unrolled when the control link passes through the center of the first end of the control link with respect to the pivot axis. And a pivot connecting the second and main lift arm links moves the tip of the main lift arm link along a substantially straight vertical trajectory when the lift arm assembly is lifted above a desired height position. The lift boom device according to claim 1. 5. The main and second lift arm links, the fluid pressure actuator means, and each side of a lift arm assembly located in a common plane and overlaid on a side of the main frame. The lift boom device according to claim 1, further comprising a control link. 6. A first end portion wherein the actuator means is pivotally mounted near a rear position of the main frame substantially below the pivot of the second link attached to the main frame, 2. A pivot connecting portion provided on the second link and a second end portion pivotally connected to the main lift arm link at an intermediate portion between the tips of the main lift arm link. Lift boom device described. 7. A loader device for a self-propelled prime mover having a main frame extending in a longitudinal direction and having front and rear ends, and an upright loader boom support member provided at a rear portion of the main frame. A loader boom assembly having a pair of lift arms mounted on each side, said each lift arm having an articulation, first and second
The first lift arm part forms a boom unit, the second lift arm part forms a rear link unit, and the first lift arm part and the upright loader boom support member on the main frame. Pivotably mounted to the rear of the rear, the second lift arm portions extend forwardly and upwardly from their pivots toward the support members of the upright loader boom, such that each first and second lift arm portion is associated with each other. The second lift arm part is substantially shorter than the first lift arm part because it is folded or expanded, and the first lift arm part extends from near the rear part of the main frame to the tip of the main frame, and at a mounting point near the tip. And a loader boom assembly having means for supporting a work implement, and a first lift arm portion and a main frame, and the tip of the first lift arm portion is moved from a lowered position to a raised position. Actuator means for providing a force for lifting upwards and a first end pivotally mounted near the front of the main frame by a first pivot, extending rearwardly therefrom and secondly Is a control link having a second end pivotally mounted to the first lift arm portion by a pivot axis for maintaining the tip of the first lift arm portion in a substantially vertical trajectory between a lowered position and a raised position. Thus, as the first pivot arm is lifted, the second pivot is provided in a predetermined position and the control link is predetermined so that the control link causes the first and second lift arms to follow their orbits. And a control link having a length of 1. 8. The control link is rotatably mounted on the main frame at a position where the height in the vertical direction is substantially lower than the pivot axis between the second lift arm portion and the upright loader boom support member, The first lift arm portion operates from a substantially horizontal position in the lowered position, and the first and second lift arm portions are associated with each other when the first lift arm portion moves upward. Pivot to initially reduce the effective length of the arcuate movement of the first lift arm tip measured between the pivot of the second lift arm section and the tip of the first lift arm section relative to the upright loader boom support member. 8. The loader device according to claim 7, wherein the load is increased thereafter, and the control link is substantially longer than the second lift arm. 9. The loader device according to claim 7, wherein the control link is substantially longer than the second lift arm portion. 10. The loader apparatus of claim 7, wherein the control link is substantially horizontal when the loader boom assembly is in its lowered position. 11. A plane defined by the pivot between the first and second lift arms and the pivot pivotally supporting the first end of the control link when the loader assembly is in its lowered position. 10. Below, there is a second pivot of the control link, wherein the second pivot of the control link moves above the plane as the loader boom assembly is lifted to a raised position. Loader device. 12. The pivot of the second lift arm section to the upright loader boom support member is substantially above the support surface of the prime mover and the pivot of the first end of the control link, the length of the control link being the upright loader boom support. It is set so that the second pivot moves above the plane when there is a work tool attachment point at the tip of the lift arm at a desired position near the height of the pivot of the second lift arm relative to the member. The loader device according to claim 11, wherein: 13. A longitudinally extending main frame, wheels that support the main frame so that they can move on the ground, and a driver's seat that extends over substantially the entire width at the front-rear center portion of the main frame. A skid steer loader that is adjacent to both sides of the driver's seat, is fixed to the main frame, and has a pair of rear frame-shaped upright members extending upward from the skid steering loader. A first and a second joint lift arm link assembly pivotably connected together, the lift arm link assembly comprising a pair of lift arm link assemblies provided at locations adjacent to both sides of the main frame. A first lift arm link assembly, the first one of the lift arm link assemblies extending forward of a main frame to support a work implement at its tip and a second one of the link arms.
The rear end of the loader boom assembly comprises a lift arm link assembly rotatably mounted on the top of a frame-shaped upright member, and a main frame and the first lift arm for lifting and lowering the loader boom assembly. A pair of fluid pressure actuators connected by connecting lift arms of a link assembly, and a pair of control links provided on both sides of the driver's seat, each of which is pivotally connected to a front portion of a main frame. A first end and a second end pivotally coupled to each lift arm of the first lift arm assembly below each first lift arm, the first and second And a control link for controlling the movement trajectory of the joint lift arm link assembly of No. 2, and each of the lift arms, control links and fluid pressure actuators provided on both sides of the driver's seat. However, in order to minimize the overall width and maximize the space for securing the lateral width of the driver's seat, the skid control is characterized by being arranged in a straight line close to the side of the main frame. Loader. 14. The second lift arm link assembly is substantially shorter than the first lift arm link assembly and shorter than the control link, and a hydraulic actuator is used to raise the first lift link. Control link urges the second lift arm link assembly to move the first lift arm link assembly backwards first, keeping it close to the front of the skid steer loader, and then further. 14. The skid steer loader according to claim 13, wherein the movement trajectory of the work implement is controlled so as to move the first lift arm link assembly forward when the work implement is raised. 15. The loader according to claim 14, wherein the loader has a rear engine room, and the second lift arm link assembly is located in front of an entrance door of the rear engine room. Skid control loader. 16. The second lift arm link assembly is substantially shorter than the first lift arm link assembly, and
14. The loader according to claim 13, wherein the lift arm link assembly is firmly pivotally supported.