GB2222997A

GB2222997A - Safety control system for backhoe

Info

Publication number: GB2222997A
Application number: GB8920142A
Authority: GB
Inventors: Hitoo Nasu; Sakae Sugawara; Takanori Miura
Original assignee: Kubota Corp
Current assignee: Kubota Corp
Priority date: 1988-09-21
Filing date: 1989-09-06
Publication date: 1990-03-28
Anticipated expiration: 2009-09-06
Also published as: DE3931255C2; GB8920142D0; GB2222997B; DE3931255A1

Description

k I d- 2,2 2 9 9 7 BACKHOE IMPLEMENT CONTROL SYSTEM FOR USE IN WORK

VEHICLE

BACKGROUND OF THE INVENTION

1 FIELD OF THE INVENTION

The present invention relates to a backhoe implement control system for use in a work vehicle having a vertically pi.%,-otable backhoe boom disposed at a lateral side of a driver's section on a turn table ai,l(-] an ofiset mechanism for horizontally moving a top r_loy-tion connected with an arm relative to a base boon! portion connected with the turn table.

2 DESCRIPTION OF THE RELATED ARTS

With a conventional backhoe work vehicle of the above-noted type with an offset mechanism. the arm carrying a bucket, when unused, may be compactly accommodated at a storing position beside the boom, such that the entire turn table may turn with a small turning radius. All operations of the arm, the top boom portion and of the base boom portion are effected manually.

More particularly, with the above-described 2.

construction, the top boom portion connected with the arm is horizontally offsettable by the offset mechanism. Thus, as illustrated in Fig. 2, if this top boom portion 10C is stored with an offset displacement toward a bucket storing side b, a backhoe' implement 6 may be accommodated within the circle defined by the turning radius of the turn table 7, such that the vehicle may turn with a small turning radius. Further, since the vehicle is operable with maintaining the bucket 8 in parallel with the base boom portion 10A, a job at a limited space is possible W i t h!) u f turniri,-, the turn table 7. This feature is 1--,I-Jicu,larly advantageous in e.g. a side ditch digging operation.

However, if the base boom portion 10A is vertically pivoted with maintaining the top boom portion 10C at its offset position toward the driver's section 4, possibility exists that the butcket 6, the top portion of the arm 9 or the like may inadvertently enter the driver's section 4. Then, if the backhoe vehicle is eq'ipped with a driver's cabin 3, there will occur dangerous contact between e.g. the bucket 8 and this cabin 3.

In principle, such happening can and should be avoided by careful and skillful maneuvering on the part of the driver. Still, the danger remains if the 3.

safety depends solely on the driver's carefulness and skill.

Accordingly, the primary object of the present invention is to provide a backhoe implementcontrol system for use in a work vehicle, which system may automatically prevent dangerous entry of the backhoe implement into the driver's section.

SUMMARY OF THE INVENTION

1 S In order to accomplish the above-noted object, in implement. control system for use in a work having a vertically pivotable backhoe boom disposed at a lateral side of a driver's section on a turn table and an offset mechanism for horizontally moving a top boom portion connected with an arm relative to a base boom portion connected turn table, the system of the invention with the comprises: detecting means for obtaining detection information including positional relationships among the turn table and te respective movable elements; backhoe position determining means for determining a position of the backhoe implement based on the detection information; restricting and safety means for automatically the movement of the backhoe implement if the backhoe implement position overlaps with a 4.

predetermined position.

With the above-described construction in operation, the detecting means provides the information including the positional relationships among the turn table and the respective movable elements, based on which information the backhoe implement position determining means determins the current position of the backhoe implement.

On the other hand, in the vicinity of the driver's section of the work vehicle, there is provided a predetermined position defining a backhoe E.,- i intrusion prohibited region into which an intru.-ion, of the backhoe device is to be avoided. Then, if there occurs a dangerous condition as the current position of the backhoe implement determined by the determining me ans has overlapped with the predetermined position, the safety means automatically restricts further movements of the backhoe implement closer to the driver's section. More particularly, if the backhoe implement being manually operated has reached the predetermined position, the safety means overrides the maunal operation and automatically and forcibly prohibits further movement of the backhoe implement beyond the predetermined position toward the driver's section.

That is to pay, the predetermined position is set -5 1 5.

at a border between the movable, i.e. permitted limit of the bucket and the prohibited region. Then, if the backhoe implement has reached the predetermined position as being manually operated, dangerous movement of the device beyond this position toward the driver's section is automatically prohibited by the safety means. Consequently, the system of the invention has achieved a greater safety operation in this type of work vehicle.

according to one preferred embodiment i, the safety means automatically the offset. mechanism to laterally offset the portion toward the bucket storing side any further Further, of the inventioi aci tup boom opposite to the driver's section if the dangerous condition has been realized with at least either a lift-up pivot operation of the boom or a pivot operation of the arm toward its operational. position. With this feature, if the manually operated backhoe device has reached the predetermined position with either of the lift-up operation of the boom and the pivot operation of the arm toward its operational position, first, the safety means overrides the manual operation and automatically and forcibly restricts further movement of the backhoe device toward the driver's section; then, the safety means automatically activates the offset mechanism to laterally offset the 6.

top boom portion toward the bucket storing side opposite to the driver's section.

Therefore, since the safety means automatically prevents the backhoe device from entering the driver's section if the backet has reached the predetermined position, the dangerous mis-intrusion of the backhoe device into the driver's section may be reliably prevented. In addition, if this movement of the backhoe has resulted from either a lift-up operation of the boom or a pivot operation of the arm, the safety means automatically operates to laterally offset the bticket away from the prohibited region back the permitted region, such that the operation may be safelv Consequently, improved also.

Further and other objects, features and effects of the invention will become apparent from the following more detailed description of the embodiments of the invention with reference to the accompanying drawings.

continued without the operation interruption.

efficiency has been 1 BRIEF DESCRIPTION OF THE DRAWINGS

Accompanying drawings illustrate preferred embodiments of a backhoe implement control system for 7.

-5 i use in relates Fig. vehicle, Fig. Fig. I, Fig. 3 is a block diagram schematically illustrating the control system, Figs. 4A and 4B illustrate an algorithm n safety means of the control system, and Figs. 5A and 5B illustrate an algorithm iy;eans used in a control system of a (7- Tn. 1) (-) d i Ili E- I i f.

a work vehicle to which the present invention in which, 1 is a side view of the backhoe work 2 is a plane view of the vehicle shown in DESCRIPTION OF THE PREFERRED EMBODIMENTS employed employed further Preferred embodiments of the invention will be particularly described hereinafter with reference to the accompanying drawings.

In Fig. 1, there is shown a backhoe work vehicle i including a vehicle body 2, a crawler type propelling device 1, a driver's section 4 equipped with a driver's cabin 3, an engine 5 and a full turn type turn table 7 mounted with a backhoe implement 6.

The backhoe implement. 6 primarily consists of an arif, 9, a bucket 8 flexibly and laterally pivotably 8.

attached to a leading end of the arm 9 and a boom 10 flexibly and laterally pivotably connecting the arm 9. The boom 10 is vertically pivotable at a side of the driver's section.

For operating the above elements constituting the backhoe implement 6, as shown also in Fig. 1, there are provided a hydraulic cylinder Cl for vertically pivoting the boom 10, a hydraulic cylinder C3 for flexing and pivoting the arm 9 relative to the boom 10 and another hydraulic cylinder C4 for flexing and 1--)ivotinE the bucket 6 relative to the arm 9.

referring to Figs. 1 and 2, there will be an offset mechanism 14 for horizontally ofisetting the arm 9 carrying the bucket 8 relative to an attaching end 10a of the boom 10 attached to the turn table 7 in a lateral direction of the turn table 7. The boom 10 includes a base boom portion 10A including the attaching end 10a, a middle boom portion 10B attached to an opposite leading end of the base portion 10A while being pivotable about a vertical axis X normal to a pivot axis of the boom 10 and a top boom portion 10C attached to an opposite leading end of the middle portion 10B while being pivotable about an axis parallel with the axis X. The aforementioned arm 9 is flexibly and pivotably attached to a free end of the top boom portion 10C. For flexing thus W 9.

constructed boom 10, there is provided, between the base boom portion 10A and the middle boom portion 10B, a boom flexing cylinder C2 for pivoting the former relative to the latter. Further, between the base boom portion 10A and the top boom portion 10C, there is provided a connecting rod 15 for permitting the pivotal movement between these boom portions 10A and loc. In sum, there is provided a parallel quadrople link mechanism consisting of the middle boom portion IOB and the connecting rod 15 both pivotably supported to the base boom portion 10A and of the top boom 1--,(:)rtiorA 1OC interconnecting the respective leading ends of the middle boom portion 10B and the connecting rod 15. Now, the base boom portion 10A, middle boom portion 10B, top boom portion 10C, arm 9 and the bucket 8 will be generically referred to as movable elements hereinafter.

Next, detecting means S, which is one essential constituent of the invention's system, will be described with reference to Fig. 3. This detecting means S includes a plurality of potentiometers Pl, P2, P3 and P4. The first potentiometer Pl as a boom angle sensor is disposed on the pivot axis Y of the base boom portion 10A so as to sense a pivot angle between the boom 10 and the turn table 7. The second potentiometer P2 as an offset sensor is disposed on 10.

the axis X interconnecting the base boom portion 10A and the middle boom portion 10B so as to sense a pivot angle between these boom portions 10A and 10B. Hence, this sensor can provide a horizontal stroke of the top boom portion 10C relative to the base boom portion 10A. The third potentiometer P3 as an arm angle sensor is disposed on the axis Z interconnecting the top boom portion 10C and the arm 9 so as to pivot angle between the same. The potentiometer P4 as a bucket angle sensor is on an axis W of a link element 32 so as to angle between the bucket 8 and the arm this detection means S as the whole provides information I including the pivot angle data sense a fourth disposed sense a 9. Thus, detection obtained by the respective potentiometers P1 through P4.

In connection with the above-described detecting means S, a backhoe position determining means 11 is provided as control means for obtaining a current position of the backhoe implement 6 based on the detection information I from the detecting means S.

I The system further includes a safety means 12 for the movable elements with an occurence of a dangerous condition. D in which the current backhoe position obtained by the determining means 11 has overlapped with a predetermined position. More particularly, with automatically disabling the drives of 11.

-5 occurence of this dangerous condition D, the safety means 12 automatically disables a lift-up pivot drive of the boom 10 by the cylinder Cl, a lateral drive of the top boom portion 10C by the cylinder C2 toward the driver's cabin 3, a pivot drive of the arm 9 by the cylinder C3 toward the boom 10 and a pivot drive of the bucket 8 by the cylinder C4 toward the boom 10.

The above-mentioned predetermined position is preliminarily set at a border between a permitted region in which the backhoe implement 6 i movable and a prohibited region in which the backhoe juir.lerflerit 6, e. g. its bucket 8 will dangerously iiitei-fere with the driver's cabin 3. With this coiistruction i and 4A, 4B, if the permitted operation on a cross control s f ree.ly n operation, as illustrated in Figs. 3 the backhoe device 6 is moved out of region to reach the border by a manual control member such as a boom-bucket lever 16, an arm-turn cross control lever 16 or on an offset mechanism control lever 17, the position of the backhoe device 6 obtained on the basis of the detection information I from the poteritiometers P1 through P4 of the detecting means S overlaps with the predetermined position, with which the safety means 12 is activated to forcibly switch over control valves 19, 20, 21, 29 of the respective hydraulic cylinders Cl, C2, C3 and C4 via 12.

corresponding control circuits 22, 23, 24 and 30, thereby to forcibly stop, in this case, the bucket 8 at the border. Incidentally, in Fig. 3, numerals 25, 26, 27 and 31 denote control means respectively for controlling the circuits 22, 23, 24 and 30 of the' valves 19, 20, 21 and 29 by means of potentiometers 16a, 1 7a, 18a and 16b attached to the control levers 16, 17 and 18.

For instance, if the bucket 8 has reached the 10)-)order when the control lever 18 alone is being Irlia Ill-1a 11 operaled in order to move the arm 9 for tl..e L)ucket 8 attached to the leading end of 1}ii-- ai-iii 9 closer to the driver's cabin 3, the bucket 8 is automatically stopped with the safety means 12 opeiating to disable only expanding movement of the arTO elyinder C3.

That is, the safety means effects a forcible switchover of the control valve 21, which is used for expanding the arm cylinder C3, to its neutral position. Further, the safety means 12 maintains this disabled condItion of the control valve 21 against the expansion of cylinder C3 until the bucket 8 returns to the permitted region.

In this condition, on the other hand, a contracting movement of the arm cylinder C3 is not disabled by the safety means 12. Also, in this stop 13.

condition, the safety means 12 disables a lift-up drive of the boom 10 which drive moves the bucket 8 closer to the cabin 3 while permiting a downward drive of the boom 10 by a manual operation on the control lever 16 which drive moves the bucket 6 away from the cabin 3.

That is to say, in the above-described stop condition, the safety,, means does not disable the operations of the cylinders Cl. C2, C3 and C4 for movina the bucket 8 away from the cabin 3.

( 'I teriiitt- Sonie. alternate embodiments of the invention will he specifically described next.

In the previous embodiment, with occurence of the dangerous condition D where the backhoe device position overlaps with the predetermined position, the safety means disables, i.e. simply stops the further movements of the backhoe implement closer to the Instead, it is conceivable to adapt this safety means 12 to automatically activate the offset mechanism 14 so as to laterally move the top boom portion 10C out of the predetermined position toward the bucket storing side (denoted by a mark W in Fig. 2) if the dangerous condtion D has been driver's cabin 3.

14.

realized by either of the lift-up pivot operation of the boom 10 and the pivot operation of the arm 9 toward the cabin 3. The control flow of this embodiment is illustrated in Figs. 5A and 5B.

More particularly, if the bucket 8 has the border when the control lever 18 alone manually operated so as to moving its bucket 8 attached to the driver's cabin, automatically serves reached is being activate the arm 9 for to the end thereof closer the safety means 12 not only to temporarily disable the expariding motion of the arm cylinder C3 but also tc, horizontally offset, in cooperation with the offset the top boom portion 10C toward the bucket storin8 side b opposite to the driver's cabin so that the temporarily disabled expanding operation may be resumed with this offset orientation. Such additional feature of the safety means may be provided similarly for the boom 10 or for the bucket 8. That is to say, conceivable to adapt the safety means 12 to activate the offset mechanism to automatically offset the top boom portion 10C towards the bucket storing side b when the bucket 8 has reached the predetermined position by its pivot operation towards the boom 10.

Moreover, it is also conceivable to adapt the safety means 12 to automatically activate the offest mechanism 14 so as to laterally offset the top boom i t i S 1 15.

portion 10C toward the bucket storing side also if a manual operation is carried out for further pivoting the bucket 8 toward the boom in the presence of the dangerous condition D.

In addition to the above constructions, the following constructions are also conceivable.

The disabling actions of the safety means 12 on the hydraulic cylinders Cl, C2, C3 and C4 may directly affect the control levers 16, 17 and 18.

The potentiometer P4 for obtaining the pivot angle between the bucket 8 and the arm 9 can be elinAnated so that the safety control may be effected Y)-ised on the detections by the three potentiometers P1, P2 and P3. In this case, if a position closest to the driver's cabin 3 in the entire pivot range of the bucket 8 relative to the arm 9 is predetermined as the border position, the dangerous interference between the bucket 8 and the cabin 3 may be similarly avoided regardless of the posture of the bucket 8.

Further, it is conceivable to provide the system with a setting device 13 which permits a variable setting of the predetermined border position.

The present invention may be embodied also in a backhoe work vehicle without the driver's cabin 3.

It is conceivable to additionally provide a warning device such as a warning buzzer which issues a 16.

warning with the occurence of the dangerous condition D.

Moreover, it is also conceivable to adapt the safety means to slow down the movements of the driven members with the occurence of the dangerous condition D.

A

Claims

A backhoe implement control system for use in a work vehicle having a vertically pivotable backhoe boom disposed at a lateral side of a driver's section on a turn table and an offset mechanism for horizontally moving a top boom.portion connected with an arm relative to a base boom portion connected with the turn table, said system comprising:

detecting means for obtaining detection information including positional relationships among thc- tui-n table and the respective movable elements; ba(-kylne position determining means for determining a current position of the backhoe implement based on said detection information; and safety means for automatically disabling movements of the backhoe implement in a dangerous condition in which said backhoe implement position overlaps with a predetermined position.

2. A sstem of Claim 1, wherein said detecting means includes a boom angle sensor for sensing a pivot angle of said boom relative to said turn table, an offset sensor for sensing a horizontal stroke of said top boom portion relative to said base boom portion and an arm angle sensor for sensing a pivot angle of 18.

said arm relative to said boom; said detection information including the angle sensed by said boom angle sensor, the stroke sensed by said offset sensor and the angle sensed by said arm angle sensor; said safety means restricting said backhoe device by restricting at least one of a lift-up pivot drive of said boom, a horizontal drive of said top boom portion toward said driver's section and a pivot drive of said arm toward said boom.

3.

A system of Claim 2, wherein said detecting furtlier includes a bucket angle sensor for seitsing a pivot angle of said bucket relative to said arm, said detection information including the angle sensed by said bucket angle sensor, said safety means restricting also a lift-up pivot drive of said bucket.

4. A system of Claim 2 or 3, wherein said safety means automatically activates said offset mechanism so as to laterally offset said top boom portion toward a bucket stoina side if said dangerous condition has been realized by at least either of a lift-up pivot drive of said boom and a pivot drive of said arm toward said driver's section.

5. A system of Claim 4, wherein said safety means 19.

automatically activates said offest mechanism so as to laterally offset said top boom portion toward the bucket storing side if said dangerous condition has been realized by a pivot drive of said bucket toward said boom.

6. A system of Claim 2 or 3, wherein said safety means completely stops said movable elements with occurence of the dangerous condition.

A system of Claim 2 or 3, wherein said safety mcans slows down said movable elements with occurence of the dangerous condition.

6. A system of Claim 2 or 3, wherein said safety means restricts movements of control members corresponding respectively to said movable members.

9. A system of Claim 1, wherein said safety means includes wajrning means for issuing a warning to the operator with occurence of the dangerous condition.

10. A system of Claim 1, wherein said predetermined position is freely settable.

11. A system of Claim 2 or 3, wherein said safety 20.

mearis automatically activates said offest mechanism so as to laterally offset said top boom portion toward the bucket stoi-iiiQ side also if a manual operation is carried out for further pivoting said bucket toward said boom in the presence of the dangerous condition. 12.

A backhoe implement control system constructed and arranged to operate substantially as herein described with reference to and as illustrated in any of the Figs. of the accompanying drawings.

1 t, Published 1990at The Patent Office. State House. 66 71 H1917.Holborr,. LondciNVCIR4TP. Further copies maybe obtainedfrom The Patent Office Sales Branch. St Ma:7," Cray. Orpington. Kent BR5 3RD. Printed by Multipl lex techniques ltd. St Mary Cray. Kent. Con. 187