JP3393720B2 - Stroke limiter for hydraulic control valve - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stroke limiting device for a hydraulic control valve, and more particularly to a stroke limiting device for a hydraulic control valve for controlling a front loader mounted on a work vehicle such as a tractor.

[0002]

2. Description of the Related Art As one configuration example of the above front loader,
There is a configuration in which a pair of left and right lift arms that move up and down hydraulically are attached to the front part of a work vehicle, and an attachment such as a bucket is attached to the tip of the lift arms. FIG. 10 is a diagram showing a configuration of a conventional front loader. Front loader 10
Reference numeral 0 has a pair of left and right lift arms 101, and the base of the lift arms 101 is vertically swingably supported at an upper position of an arm base frame 103 attached to a machine frame 102. The machine frame 102 is mounted at the front position of the work vehicle 104.

The lift arm 101 is vertically swung by a lift cylinder 106 which is supported at a lower position of the arm base frame 103 so as to be vertically swingable. An attachment frame 107 is supported at the tip of the lift arm 101 by a pin 108 so as to be vertically swingable,
The bucket 110, which is an attachment, is attached to the attachment frame 107. A dump cylinder 111 is provided at the center of the upper side of the lift arm 101, and the link mechanism 112 swings the bucket 110 up and down. Further, a hydraulic control valve 113 that drives and controls the lift cylinder 106 and the dump cylinder 111 is attached to the driver's seat side of the machine casing 102.

FIG. 11 shows a control panel 114 for the hydraulic control valve 113.
FIG. The hydraulic control valve 113 operates the operation lever 115 to operate the front loader 10.
16 states (4 × 4 = 16) showing the control state of 0
Can be changed to That is, as shown in FIG. 10, the lift cylinder 101 can be lifted and lowered by extending and shortening the lift cylinder 106, and the squeeze operation 122 and
The dump operation 124 can be obtained.

In addition to the above operation, the hydraulic control valve 11
By the operation of No. 3, the speed increasing dump operation for increasing the speed to perform the dump operation of the bucket 110 and the floating operation for changing the lift position of the lift arm 101 by the external force can be performed. In the hydraulic control valve 113 having the above-described configuration, in order to prevent the operation lever 115 from being accidentally driven to the position of the speed increasing dump operation or the floating operation in a state not intended by the operator, the normal operation of the operation lever 115 is performed. If the operating force is stronger than the force, it is impossible to shift to the speed-up dumping operation and the floating operation.

[0006]

However, depending on the contents of the work of the front loader 100, there is a case where the speed increasing dump operation or the floating operation is not used at all, and in that case, the speed increasing dump operation is unnecessary, When the operation lever 115 is operated to the floating operation position, there is a problem that work efficiency is reduced.

Explaining further, the front loader 1 described above
The general operation in 00 is a combination operation of the lifting operation of the lift arm 101, the lowering operation, the dumping operation of the bucket 110, and the squeeze operation, and the speed increasing dumping operation and the floating operation are operations that are rarely used. Therefore, the possibility that the operation lever 115 may be in the speed increasing dump operation position or the floating operation position when an operator performs a general operation in the front loader 100 is an obstacle to performing a smooth operation. It will end up.

To solve this problem, in addition to the hydraulic control valve 113 for controlling other basic operations, a dedicated hydraulic control valve for controlling the speed-up dumping operation and the floating operation is newly provided to provide a two-step hydraulic control operation. By front loader 1
Although a method of controlling 00 is also conceivable, there is a problem that the operation becomes complicated in the case of the work using the speed-up dumping operation and the floating operation, and the hydraulic control mechanism becomes complicated and the manufacturing cost rises.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art.
An object of the present invention is to provide a stroke limiting device for a hydraulic control valve that can reliably regulate floating operation and speed-up operation with a simple configuration.

[0010]

A stroke limiting device for a hydraulic control valve according to a first aspect of the present invention for achieving the above object is, for example, a vertical direction by a lift cylinder 6 when explained with reference to FIGS. A lift arm 2 swingable to
The stroke limit of the hydraulic control valve 31 for controlling the front loader 1 including the attachment 5 supported on the tip of the lift arm 2 so as to be vertically swingable, and the dump cylinder 7 for vertically swinging the attachment 5. The hydraulic control valve 31 is a linear lift spool 37.
And a linear dump spool 38, and the two spools 37, 38 are provided on the inlet side end surface 3 of the hydraulic control valve 31.
9 is driven by a spool operating link 42 supported by a fulcrum member 41, and the lift cylinder 2 and the dump cylinder 7 are controlled and driven by control positions of the two spools 37 and 38, whereby the lift arm 2 is lifted. , A descending operation, a squeezing operation of the attachment 5 and a dumping operation are achieved, and at least one of a floating operation of the lift arm 2 and a speed increasing dumping operation of the attachment 5 is performed.
The spool operation link 42 has a right-angled triangle KLM having vertices K, L and M on one surface 44 of the operation plate 43.
When a perpendicular KN is drawn on the side LM facing the right-angled vertex K of the right-angled triangle KLM, the other two vertices L, M
2 of a triangle K'LM consisting of and a point K'on the perpendicular KN
A first engaging groove 45 and a second engaging groove 46 are formed along the sides K′L and K′M, and a third member extending at a position of the point K ′ in a substantially central direction of the triangle K′LM. It is configured such that a joint groove 47 is formed and an operation lever 49 is attached to a predetermined position on the other surface 48 of the operation plate 43. The engaging portion 37a of the linear lift spool 37 is connected to the first engaging groove. 45
To the engaging portion 3 of the linear dump spool 38.
8a is engaged with the second engagement groove 46, and the fulcrum member 4
The engaging portion 41a of No. 1 is engaged with the third engaging groove 47, and the linear lift spool 37 and the linear At least one of a floating operation and a speed-up operation in driving the shape dump spool 38.
It is characterized in that a regulating means 52 for regulating one is provided.
The regulating means 52 is provided on the inlet side end surface 39 of the hydraulic control valve 31.
And the spool operation link 42.

A stroke limiting device for a hydraulic control valve according to a second aspect of the present invention will be described with reference to FIGS. 1 to 9, for example, a lift arm 2 which is vertically swung by a lift cylinder 6, and the lift arm 2. Is a stroke limiting device for the hydraulic control valve 31 for controlling the front loader 1, which includes an attachment 5 that is swingably supported at the tip of the front end and a dump cylinder 7 that swings the attachment 5 in the vertical direction. The hydraulic control valve 31 includes a linear lift spool 37 and a linear dump spool 38.
The two spools 37, 38 are driven by a spool operation link 42 supported by a fulcrum member 41 on the inlet-side end surface 39 of the hydraulic control valve 31.
By controlling and driving the lift cylinder 6 and the dump cylinder 7 by the control position of 38, the lift arm 2 is moved up and down, and the attachment 5 is moved.
Of the lift arm 2 and at least one of the speed-up dumping operation of the attachment 5 are performed, and the spool operation link 42 has its operation plate. 43
Considering a right-angled triangle KLM consisting of vertices K, L, and M on one surface 44, and when a perpendicular KN is drawn on a side LM facing the right-angled vertex K of the right-angled triangle KLM, the other two vertices L, A triangle K'L consisting of M and a point K'on the perpendicular KN
Along the two sides K'L, K'M of M, the first engaging groove 45, the second
The third engaging groove 47 is formed at the position of the point K ′ and extends in the substantially central direction of the triangle K′LM while forming the engaging groove 46.
And the operation lever 49 is attached to a predetermined position on the other surface 48 of the operation plate 43, and the engagement portion 37a of the linear lift spool 37 is engaged with the first engagement groove 45. And the engaging portion 38a of the linear dump spool 38 is engaged with the second engaging groove 46, and the engaging portion 41a of the fulcrum member 41 is engaged with the third engaging groove 47, The inlet-side end surface 3 of the hydraulic control valve 31
9 at the end position on the opposite side to 9
7. It is characterized in that the linear dump spool 38 is provided with restriction means 95, 96 for restricting at least one of a floating operation and a speed-up operation when driving the linear dump spool 38.

[0012]

According to the stroke limiting device of the hydraulic control valve of the first aspect, when the operator operates the operation lever 49 of the spool operation link 42, the spool operation link 42 is tilted with the fulcrum member 41 as a fulcrum. Become. Due to the inclination of the spool operation link 42, the first engagement groove 45,
The linear lift spool 37 and the linear dump spool 38 which are respectively engaged with the second engagement groove 46 are driven to a predetermined hydraulic control position. In this case, since the control means 52 (for example, the stroke stopper) is provided, before the worker performs the work, the operator can select whether to enable the floating operation or the speed-up dump operation, or not. You can

That is, by making the restriction by the restricting means 52 not work at all, both the floating operation and the speed-up dump operation can be performed. Also,
By restricting only the floating operation of the restricting means 52, it is possible to make only the speed increasing dump operation possible. In addition, of the regulation means 52,
By restricting only the speed-up dump operation, only the floating operation can be performed. As described above, by providing the restricting means 52, it is possible to reliably prevent an unintended work operation of the front loader 1 due to an operator's operation error of the operation lever 49, and it is possible to improve work efficiency. .

Further, by providing the regulating means 52 closer to the spool operation link 42 than the inlet side end surface 39 of the hydraulic control valve 31, the regulating means 5 is located at a position close to the operation lever 49.
Since 2 is provided, there is an advantage that the operator can easily perform the switching operation of the regulation.
In addition, the regulating means 52 is provided on the inlet side end surface 39 of the hydraulic control valve 31.
If provided between the spool operating link 42 and the spool operating link 42, the regulating means 52 is provided on the inlet side end surface 39 or the spool operating link 42.
It is possible to simplify the attachment of the regulating means 52.

According to the stroke limiting device of the hydraulic control valve of the second aspect, the operating lever of the operator is provided by providing the restricting means 95 and 96 similarly to the operation of the stroke limiting device of the hydraulic control valve of the first aspect. By the operation mistake of 49,
It is possible to reliably prevent an unintended work operation from being performed. Further, by providing the regulating means 95, 96 at the end position of the hydraulic control valve 31 opposite to the inlet side end surface 39, the stroke of the spool can be made by a very simple mechanism (for example, a regulating bolt, a regulating screw, etc.). It has the advantage of being configurable.

[0016]

As described in the above operation, according to the invention of claim 1, the following peculiar effects can be obtained. (B) By providing the restricting means, it is possible to easily and reliably prevent the operation lever from being erroneously operated to the position of the speed increasing dump operation or the floating operation during the work not using the floating operation or the speed increasing dump operation. You can
Work efficiency can be improved.

(B) Providing the regulating means on the spool operation link side with respect to the inlet side end surface means that the regulating means is provided near the driver's seat for operating the front loader. There is an advantage that it is easy to perform a switching operation to switch between a state of using and a state of not using.

According to the invention of claim 2, in addition to the effect of the above (a), the following specific effect of (c) can be exhibited. (C) The restriction means may be configured to suppress the movement of the lift spool and the dump spool by providing the restriction means at an end position on the opposite side of the inlet side end surface of the hydraulic control valve. Therefore, the restricting means can be composed of a restricting bolt, a restricting screw, etc. provided at the lower end of each spool, and the structure of the restricting means can be made extremely simple.

[0019]

Embodiments will be described in detail below with reference to the accompanying drawings showing embodiments. FIG. 8 is a side view showing a front loader to which the stroke limiting device for a hydraulic control valve according to the present invention is applied. As shown in FIG. 8, the front loader 1 includes a pair of left and right lift arms 2 and a pair of left and right arm base frames 3 attached to the base ends of the lift arms 2.
A pair of left and right attachment frames 4 attached to the tip end side of the lift arm 2 and the attachment frame 4
A pair of left and right links including a bucket 5 detachably attached to the vehicle, a pair of left and right lift cylinders 6 for vertically swinging the lift arm 2, and a pair of left and right dump cylinders 7 for vertically swinging the bucket 5. And the mechanism 8.

Vehicle body side brackets 11 are attached to the left and right sides of the bonnet rear portion of the vehicle body 10a of the tractor 10. The arm loader frame 3 is detachably attached to the vehicle body side brackets 11 to attach the front loader 1 to the front loader 1. It is configured to be detachably attached to the vehicle body 10a.

The lift arm 2 has a curved shape that is slightly closer to the center side toward the base end side, and its base end is supported by a pin 12 at an upper position of the arm base frame 3 so as to be vertically swingable. The tip of the lift arm 2 is supported by a pin 13 on the attachment frame 4 so as to be vertically swingable.
The base of the lift cylinder 6 is swingably supported at the front side position of the arm base frame 3 by the pin 14, and the tip of the lift cylinder 6 is vertically swingably attached to the center of the lift arm 2 by the pin 15.

The link mechanism 8 has a dump cylinder 7 which is vertically swingably supported by a dump plate 16 which is fixed to the upper side of the central portion of the lift arm 2, and one end of which can swing freely to the tip of the dump cylinder 7. A connecting rod 20 is attached, the other end of which is vertically swingably attached to the attachment frame 4, one end of which is swingably attached to the tip of the dump cylinder 7, and the other end of which is a pin below the tip of the lift arm 2. It is composed of a crank 22 which is swingably attached by 21. A hydraulic control valve 31 that controls the front loader 1 is attached to the front loader 1 via a stay 32.

By the control operation of the hydraulic control valve 31,
As shown in FIG. 8, the lifting and lowering operations of the lift arm 2 can be obtained by the extension and shortening operations of the lift cylinder 6, and the squeeze operation 24 and the dumping operation 25 can be obtained by the extension and shortening operations of the dump cylinder 7. . In addition to that, it is possible to perform a speed increasing dump position for increasing the speed to perform the dumping operation, and a floating operation in which the lift position can be changed by the force applied to the lift cylinder 6.

FIG. 1 is a plan view of a hydraulic control valve for controlling the front loader, FIG. 2 is a front view, and FIG. 3 is an exploded perspective view. The hydraulic control valve 31 includes two spool pipe lines 35 and 36 provided in parallel in a base body 34, a linear lift spool 37 and a linear dump spool 38 which are inserted into the spool pipe lines 35 and 36, and Spool pipes 35, 36
A fulcrum member 41 attached at a predetermined position on the inlet side end surface 39 of the above, a spool operation link 42, and a stroke stopper 52.

As shown in FIG. 1, the spool operation link 42 has a first engagement groove 45 and a second engagement groove 46 formed on one surface 44 of the operation plate 43 along two orthogonal sides of a right triangle 50. And a third engaging groove 47 extending substantially in the central direction of the right triangle 50 is formed at a right angle position,
An operation lever 49 is attached to a predetermined position on the other surface 48. Further, the first engagement groove 45 and the second engagement groove 46 engage with the ball joints 37 a and 38 a of the linear lift spool 37 and the linear dump spool 38, and the third engagement groove 47 the ball of the fulcrum member 41. It is configured to engage with the joint 41a. The operation plate 43 of the spool operation link 42 is the fulcrum member 4
By tilting with respect to 1, the wrist spool 37 and the dump spool 38 can take a predetermined hydraulic control position, and the front loader 1 can be operated in a predetermined operation.

The spool operation link 42 can be adopted in a structure other than the structure in which the first engaging groove 45 and the second engaging groove 46 are formed along the two sides of the right triangle 50 which are orthogonal to each other. FIG. 4 is a diagram for explaining another configuration of the spool operation link. In this spool operation link, a right-angled triangle KLM consisting of vertices K, L, and M is considered on the surface 44 of the operation plate 43 in which the engagement groove is formed, and a perpendicular line KN to the side LM facing the right-angled vertex K of the right-angled triangle KLM. , The first engaging groove 45 is formed along the two sides K′L and K′M of the triangle K′LM that is composed of the other two vertices L and M and the point K ′ on the perpendicular KN. The second engaging groove 46 is formed, and the third engaging groove 47 extending substantially in the center direction of the triangle K′LM is formed at the position of the point K ′.

As described above, the first to third engagement grooves 45, 46,
The spool operation link 42 can also be formed by forming 47.
Can be configured. The first to third engagement grooves 4
Needless to say, the arrangement of the lift spool 37, the dump spool 38, and the fulcrum member 41 changes depending on the arrangement direction of 5, 46, 47.

Stroke stopper 52 as a regulating means
In this embodiment, as shown in FIGS. 1 to 3, the inlet side end surface 39 of the hydraulic control valve 31 and the spool operation link 42 are
It is provided between and. The stroke stopper 52 includes at least one of the dump restricting member 53 and the lift restricting member 54. The dump restricting member 53 is configured by swingably attaching a dump swing member 57 to a pivot pin 55 provided upright at a position near the dump spool 38. The lift restricting member 54 is configured by swingably attaching a lift swinging member 59 to a pivot pin 58 provided upright at a position near the lift spool 37.

At the end of the dump swing member 57, there is provided a restriction projection 61 for restricting the operation of the dump spool 38 to the speed increasing dump position by hitting the dump side contact portion 60 of the spool operation link 42. Has been. Further, at the end of the lift swinging member 59, there is provided a restriction projection 64 that restricts the operation of the lift spool 37 to the floating position by hitting the lift side contact part 62 of the spool operation link 42. . The dump swing member 57 and the lift swing member 59 are respectively indicated by X,
It is possible to take two positions of Y, the speed increasing dump restriction state and the floating restriction state are respectively taken at the X position, and the restriction release state is taken at the Y position.

FIG. 5 is a view showing an operation panel for operating the hydraulic control valve of the front loader, which has the same structure as the operation panel shown in FIG. 11 and shows a state in which the front loader is operated. By tilting the spool operation link in a predetermined direction (see FIG. 11), it is possible to perform a combination of ascending operation, descending operation, squeezing operation, dumping operation, speed increasing dumping operation, and floating operation. Specifically, by controlling the operation lever 49 (see FIG. 3) to each position of [1] to [16], [1] neutral, [2] up, [3]
Descend, [4] Squeeze, [5] Dump, [6] Ascend Dump, [7] Ascend Squeeze, [8] Descent Squeeze, [9] Descent Squeeze, [10] Floating Dump, [11] Accelerated Dump, [12] ] Each operation of a floating squeeze, [13] floating dump, [14] rising speed dump, [15] falling speed dump, and [16] floating speed dump can be performed.

FIG. 6 is a view showing the lower structure of the wrist spool and the dump spool of the hydraulic control valve, and FIG. 7 is a hydraulic circuit diagram. In FIG. 6, a housing 65 for accommodating the spool tip is provided at the lower end of each spool 37, 38. The inside of the housing 65 is partitioned from the tip side into a first chamber 67 and a second chamber 68 by a partition wall 66 having an opening at the center. An engaging member 69 is attached to the tip of each spool 37, 38, and the engaging member 69 has a tip engaging portion 70 and an intermediate engaging portion 71. In the first chamber 67 of the dump spool 38, a pair of springs 73 accommodated in the spool axial direction are urged and the tip engaging portion 7 is provided.
A first spring receiver 74 engaging with 0 is provided, and a second chamber 68 is provided.
Is provided with a second spring receiver 75 that engages with the intermediate engaging portion 71 and a third spring receiver 76 that engages with the spool shoulder portion, and a pair of second spring receivers 75 and 76 are provided between the second spring receiver 75 and the third spring receiver 76. Spring 7
8 are provided.

The dump spool 38 has a speed increasing dump position, a dump position, a neutral position, and a squeeze position in order from the lower end side. In order for the tip engaging portion 70 to move from the dump position to the speed increasing dump position. Since it is necessary to overcome the biasing force of the spring 73 by the first spring receiver 74 and the spring 78 by the third spring receiver 76 to operate to the speed increasing dump position, the operator must move to the speed increasing dump position. It is necessary to increase the operating force of the operating lever. Further, in this configuration, the speed-up dump operation is executed only during the time when the dump spool 38 is operated to the speed-up dump position.

Further, a cylindrical member 81 having an opening for accommodating the ball 80 on the peripheral surface is provided in the first chamber 67 of the lift spool 37, and in the first chamber 67 in a state of being in contact with the ball 80. Pressing member 83 biased by a pair of springs 82
Is fitted on the tubular member 81. Similarly to the second chamber 68 of the dump spool 38, the second chamber 68 is provided with a second spring receiver 75 that engages with the intermediate engaging portion 71 and a third spring receiver 76 that engages with the spool shoulder. A pair of springs 78 is provided between the second spring receiver 75 and the third spring receiver 76.

The lift spool 37 has a floating position, a descending position, a neutral position, and an ascending position in order from the lower end side. In order for the tip engaging portion 70 to move from the descending position to the floating position, the third spring is used. Receiving 76
Against the urging force of the spring 78 by the ball 80
Since it is necessary to push the to the pressing member 83 side to move the tip end engaging portion 70, the operator needs to increase the operation force of the operation lever in order to move to the floating position. Further, in this configuration, since the tip engaging portion 70 is held at that position by the locking force of the ball 80 in the floating position (indicated by the two-dot chain line reference numeral 84), the operator operates to return the operation lever. Unless otherwise, the front loader will remain floating.

In FIG. 7, the hydraulic pump 85 of the tractor is shown.
The hydraulic pressure from is supplied to the lift cylinder 6 via the lift spool 37 and is supplied to the dump cylinder 7 via the dump spool 38. In the hydraulic circuit diagram, reference numeral 86 is a speed-up dump oil passage of the dump spool 38,
Reference numeral 87 is a dump oil passage, reference numeral 88 is a neutral oil passage, reference numeral 89.
Is a squid oil passage, 90 is a floating oil passage 90 of the lift spool 37, 91 is a descending oil passage, 92 is a neutral oil passage, and 93 is an ascending oil passage. In FIG. 7, the oil pipe N is connected to the hydraulic cylinder of the three-point link mechanism of the tractor.

Next, the operation of the hydraulic control valve having the above structure will be briefly described. By operating the hydraulic control valve 31 with the operating lever 49 (see FIG. 3) of the spool operating link 42, the state of the front loader 1 is brought into each control state shown in FIG. In this case, by setting both the dump swing member 57 and the lift swing member 59 of the stroke stopper 52 to the Y position, the operation lever 49 in FIG. 5 is moved to all positions [1] to [16]. Can be put in.

By setting the swinging member 57 for dump to the X position and the swinging member 59 for lift to the Y position, the operating lever 49 is moved to [1] to [9], [10], [12],
It can be put in each position of [13], and only the speed-up dumping operation can be restricted. Further, by setting the dump swing member 57 to the Y position and the lift swing member 59 to the X position, the operation lever 49 is moved from [1] to [1].
It can be placed in the positions [9], [11], [14], and [15], and only the floating operation can be restricted.

Further, when both the dump swing member 57 and the lift swing member 59 are set to the X position, the operation lever enters only the positions [1] to [9], and both the speed increasing dump operation and the floating operation are performed. Can be regulated. In this way, the speed increasing dumping operation and the floating operation can be easily regulated.

[0039]

Second Embodiment FIG. 9 is a view showing the lower structure of a hydraulic control valve showing a second embodiment of the present invention. The feature of this embodiment is that the stroke stopper as the restricting means is not provided on the inlet side end face 39 side of the hydraulic control valve 31, but is provided at the end position opposite to the inlet side end face 39. That is, in FIG. 9, a regulation bolt 95 is provided at the lower end of the housing 65 of the dump spool 38 to prevent the tip engaging portion 70 from being located at the speed increasing dump position. Further, a regulation bolt 96 is provided at the lower end of the housing 65 of the lift spool 37 to prevent the tip engaging portion 70 from being located at the floating position.

The restricting bolts 95 and 96 are constructed so that the restricting position is held by the fixing screw 97. Therefore, when the speed increasing dump operation is not used, the restriction bolt 95 is projected into the housing 65 to prevent the tip engaging portion 70 from entering the speed increasing dump position, and when the floating operation is not used, the restriction bolt 96 is inserted into the housing. It suffices that the tip end engaging portion 70 does not enter the floating position by projecting into the inside of 65.

With this configuration, since the configuration is simple and the operator is in the lower position of the hydraulic control valve 31 which cannot be easily touched, the operator can perform the speed increasing dumping operation and the floating operation for a long period of time. When it is not necessary, it is highly effective in preventing erroneous operation by the operator. In addition, by increasing the protruding length of the restriction bolts 95 and 96 in the second embodiment, there is an advantage that the spool cannot be operated to the dump position and the descend position beyond the speed increasing dump position and the floating position. is there. In this case, the regulation bolt 9
There is an advantage that the fine adjustment operation of descending / dumping can be easily performed by adjusting the protruding length of 5, 96. The present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the present invention. Hereinafter, such an embodiment will be described.

(1) In the first embodiment, the stroke stopper 52 is provided between the inlet-side end surface 39 of the hydraulic control valve 31 and the spool operation link 42. This is because the speed increasing dump position and the floating position shown in FIG. 6 are on the lowest side (the side opposite to the inlet side end surface 39) and restrict the pressing operation of the spool operation link 42. Therefore, when the speed increasing tamping position and the floating position of the dump spool 38 and the lift spool 37 are at the uppermost position on the inlet side end face 39 side, the pulling operation of the spool operating link 42 may be restricted. In this case, a stroke stopper for restricting the lifting of the dump spool 38 and the lift spool 37 to the speed increasing dump position and the floating position is provided in the casing (not shown) that accommodates the spool operation link 42. good.

(2) In the first embodiment, the stroke stopper 52 is attached to the inlet side end surface 39 of the hydraulic control valve 31, but the surface of the spool operating link 42 facing the inlet side end surface 39 of the spool operating link 42. The pivot pins 55 and 58 may be erected on the shaft 44, and the dump swing member 57 and the lift swing member 59 may be attached to the pivot pins 55 and 58.

(3) In the first embodiment, the swinging direction of the dump swing member 57 and the lift swing member 59 of the stroke stopper 52 is parallel to the inlet side end face 39. However, it may be configured to swing in the direction perpendicular to the inlet-side end surface 39. In this case, the pivot pin is provided in parallel with the surface 44 of the operation plate 43. Further, the stroke stopper is not limited to the swing structure, and may be configured to be inserted between the inlet side end surface 39 and the spool operation link 42 by sliding a plate-like object that regulates the inclination of the spool operation link 42.

[Brief description of drawings]

FIG. 1 is a plan view of a hydraulic control valve according to the present invention.

FIG. 2 is a front view of a hydraulic control valve according to the present invention.

FIG. 3 is an exploded perspective view for schematically explaining a hydraulic control valve.

FIG. 4 is a diagram for explaining another configuration of the spool operation link according to the present invention.

FIG. 5 is a view showing an operation panel of a hydraulic control valve.

FIG. 6 is a diagram showing a lower configuration of a wrist spool and a dump spool of the hydraulic control valve according to the first embodiment of the present invention.

FIG. 7 is a hydraulic circuit diagram according to the present invention.

FIG. 8 is a diagram showing a configuration example of a front loader to which the present invention is applied.

FIG. 9 is a view showing a lower structure of a hydraulic control valve showing a second embodiment of the present invention.

FIG. 10 is a diagram showing a configuration of a conventional front loader.

FIG. 11 is a diagram showing a relationship between an operation panel of a hydraulic control valve and an operation lever.

[Explanation of symbols]

1 ... Front loader, 2 ... Lift arm, 5 ... Bucket, 6 ... Lift cylinder, 7 ... Dump cylinder, 31 ...
Hydraulic control valve, 37 ... Linear lift spool, 37a ... Engagement portion of linear lift spool, 38 ... Linear dump spool, 38a ... Engagement portion of linear dump spool, 39 ...
Inlet side end surface of hydraulic control valve, 41 ... fulcrum member, 41a ... Engaging portion of fulcrum member, 42 ... Spool operation link, 43 ... Operation plate, 44 ... One surface of operation plate, 45 ... First engagement groove, Four
6 ... 2nd engaging groove, 47 ... 3rd engaging groove, 48 ... The other surface of an operating plate, 49 ... Operating lever, 52 ... Stroke stopper, 95, 96 ... Regulator bolts.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16K 31/44-31/62 F15B 13/042

Claims (2)

(57) [Claims] 1. A lift arm (2) swingable in a vertical direction by a lift cylinder (6), an attachment (5) supported by a tip portion of the lift arm (2) so as to be swingable vertically, and A stroke limiting device for a hydraulic control valve (31) for controlling a front loader (1) including a dump cylinder (7) for swinging an attachment (5) in a vertical direction, wherein the hydraulic control valve (31) is a straight line. Shape lift spool (3
7) and a linear dump spool (38), wherein the two spools (37) (38) include the hydraulic control valve (3).
1) is driven by a spool operation link (42) supported by a fulcrum member (41) on the inlet side end face (39), and the lift cylinder (6) and the lift cylinder (6) are controlled by the control positions of the two spools (37) (38). By controlling and driving the dump cylinder (7), the lift arm (2) can be moved up and down, the attachment (5) can be squeezed and dumped, and the lift arm (2) can be floated. , The attachment (5) is configured to perform at least one of the speed-up dumping operations, and the spool operation link (42) has its operation plate (4).
3) Consider a right triangle (KLM) consisting of vertices (K) (L) (M) on one surface (44) of the right triangle (K).
When a perpendicular (KN) is drawn on the side (LM) facing the right-angled vertex (K) of LM), the other two vertices (L) (M)
And along the two sides (K'L) (K'M) of the triangle (K'LM) consisting of the point (K ') on the vertical line (KN)
The engagement groove (45) and the second engagement groove (46) are formed, and at the position of the point (K ′), the third engagement groove (47) extending in the substantially central direction of the triangle (K′LM). And the operation lever (49) is attached to a predetermined position on the other surface (48) of the operation plate (43), and the engaging portion (37a) of the linear lift spool (37) is formed.
Is engaged with the first engaging groove (45), the engaging portion (38a) of the linear dump spool (38) is engaged with the second engaging groove (46), and the fulcrum member (41). ) Is engaged with the third engagement groove (47), and is closer to the spool operation link (42) side than the inlet side end face (39) of the hydraulic control valve (31). , The linear lift spool (37), the linear dump spool (3)
A stroke limiting device for a hydraulic control valve, comprising: a regulating means (52) for regulating at least one of a floating operation and a speed-up operation in the drive of 8). 2. A lift arm (2) swingable in a vertical direction by a lift cylinder (6), an attachment (5) supported by a tip portion of the lift arm (2) so as to be swingable vertically, and A stroke limiting device for a hydraulic control valve (31) for controlling a front loader (1) including a dump cylinder (7) for swinging an attachment (5) in a vertical direction, wherein the hydraulic control valve (31) is a straight line. Shape lift spool (3
7) and a linear dump spool (38), wherein the two spools (37) (38) include the hydraulic control valve (3).
1) is driven by a spool operation link (42) supported by a fulcrum member (41) on the inlet side end face (39), and the lift cylinder (6) and the lift cylinder (6) are controlled by the control positions of the two spools (37) (38). By controlling and driving the dump cylinder (7), the lift arm (2) can be moved up and down, the attachment (5) can be squeezed and dumped, and the lift arm (2) can be floated. , The attachment (5) is configured to perform at least one of the speed-up dumping operations, and the spool operation link (42) has its operation plate (4).
3) Consider a right triangle (KLM) consisting of vertices (K) (L) (M) on one surface (44) of the right triangle (K).
When a perpendicular (KN) is drawn on the side (LM) facing the right-angled vertex (K) of LM), the other two vertices (L) (M)
And along the two sides (K'L) (K'M) of the triangle (K'LM) consisting of the point (K ') on the vertical line (KN)
The engagement groove (45) and the second engagement groove (46) are formed, and at the position of the point (K ′), the third engagement groove (47) extending in the substantially central direction of the triangle (K′LM). And the operation lever (49) is attached to a predetermined position on the other surface (48) of the operation plate (43), and the engaging portion (37a) of the linear lift spool (37) is formed.
Is engaged with the first engaging groove (45), the engaging portion (38a) of the linear dump spool (38) is engaged with the second engaging groove (46), and the fulcrum member (41). ) Is engaged with the third engagement groove (47), and the linear shape is provided at an end position opposite to the inlet side end surface (39) of the hydraulic control valve (31). Lift spool (37),
A stroke limiting device for a hydraulic control valve, comprising: regulating means (95) (96) for regulating at least one of a floating operation and a speed-up operation in driving the linear dump spool (38).