JPS60112935A - Hydraulic circuit of construction equipment - Google Patents
Hydraulic circuit of construction equipmentInfo
- Publication number
- JPS60112935A JPS60112935A JP21955183A JP21955183A JPS60112935A JP S60112935 A JPS60112935 A JP S60112935A JP 21955183 A JP21955183 A JP 21955183A JP 21955183 A JP21955183 A JP 21955183A JP S60112935 A JPS60112935 A JP S60112935A
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- switching valve
- cylinder
- oil
- rod
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/226—Safety arrangements, e.g. hydraulic driven fans, preventing cavitation, leakage, overheating
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Operation Control Of Excavators (AREA)
Abstract
Description
【発明の詳細な説明】 本発明は、建設機械の油圧回路に関するものである。[Detailed description of the invention] The present invention relates to a hydraulic circuit for construction machinery.
従来の建設機械の油圧回路を第１図乃至第３図を参照し
て説明する。この例示のものは、油圧ショベルのアーム
シリンダの油圧回路にかかるものである。油圧ンヨベル
は第２図および第３図に示すように本体８にブーム８ａ
を回動可能に取付け、そのブーム８ａにアームｌＯを回
動ｉｉＪ能に取付け、そのアーム１０にパケット１１を
回動可能に取付け、前記ブーム８ａとアーム１０とにア
ームシリンダ９を取付けたもので、アームシリンダ９を
伸縮させることによりアーム１０を回動させる。かかる
油圧ショベルのアームシリンダ９の従来の油圧回路ハ、
第１図に示すように、油圧ポｙ７’５に方向制御弁１を
接続し、その方向側（ホ）弁１にアームシリンダ９を接
続し、前記方向制御弁１に操作レバー７を連係したもの
である。図中、符号６は油タンクである。次に、その操
作について説明する。前記操作レバー７を操作して方向
切換弁１を切換え、油圧ボン７’５からの圧油をアーム
シリンダ９のロッド側３またはボトム側４に供給してロ
ッド１４ａを縮めたりまたは伸したりし５同時に、＋１
−ム側４またはロッド側３の油を油タンク６に戻す。A conventional hydraulic circuit for construction machinery will be explained with reference to FIGS. 1 to 3. This example relates to a hydraulic circuit for an arm cylinder of a hydraulic excavator. As shown in FIGS. 2 and 3, the hydraulic yawbel has a boom 8a on the main body 8.
is rotatably mounted, an arm lO is rotatably mounted on the boom 8a, a packet 11 is rotatably mounted on the arm 10, and an arm cylinder 9 is mounted on the boom 8a and the arm 10. , the arm 10 is rotated by extending and contracting the arm cylinder 9. The conventional hydraulic circuit of the arm cylinder 9 of such a hydraulic excavator c.
As shown in FIG. 1, a directional control valve 1 was connected to the hydraulic pressure point 7'5, an arm cylinder 9 was connected to the directional side (E) valve 1, and an operating lever 7 was linked to the directional control valve 1. It is something. In the figure, numeral 6 is an oil tank. Next, the operation will be explained. The control lever 7 is operated to switch the directional control valve 1, and pressure oil from the hydraulic cylinder 7'5 is supplied to the rod side 3 or bottom side 4 of the arm cylinder 9 to retract or extend the rod 14a. 5 at the same time, +1
- Return the oil on the arm side 4 or rod side 3 to the oil tank 6.
しかしながら、上述の従来の油圧回路は、方向制御弁１
にアームシリンダ９をただ単に接続しただけのものであ
るから、例えばアームシリンダ９を伸ばす場合、すなわ
ちアーム１０が第３図の状態から第２図の状態に回動す
る場合、負荷すなわちアーム１０やパケット１１などの
重量によりロッド１４ａがのば石れ、同時にアーム／リ
ンダ９のぎトム側４に圧油が流入する。しかし、この流
入量がピストン１４の動き量に対して不足すると、先行
中のピストン１４の動きが一旦止まり、アームシリンダ
９のボトム側４に圧油が供給袋れて流入量が追いつき不
足量がなくなったとき再ひピストン１４が動きだすと菖
う所謂息つき現象を起す。However, in the conventional hydraulic circuit described above, the directional control valve 1
For example, when the arm cylinder 9 is extended, that is, when the arm 10 is rotated from the state shown in FIG. The rod 14a is stretched due to the weight of the packet 11, etc., and at the same time, pressure oil flows into the shaft side 4 of the arm/linda 9. However, if this inflow amount is insufficient for the amount of movement of the piston 14, the movement of the piston 14 that is leading stops temporarily, pressure oil is supplied to the bottom side 4 of the arm cylinder 9, the inflow amount catches up, and the insufficient amount is replaced. When the piston 14 starts moving again when it runs out, a so-called breathing phenomenon occurs.
そこで、従来は上述の息つき現象をなくすため、方向制
御弁１とアームシリンダ９のロッド側３とを結ぶ油路の
途中に絞り弁１５を設け、アーム７リンダ９のロッド１
４ａの伸ひる速さを＆）ム側４に圧油が流入してピスト
ン１４が動く速度以下に遅くし、上述の息つき現象を起
さないようにする油圧回路となっていた。しかしながら
、この場合アームシリンダ９のロッド１４ａの伸ひる速
度はボトム側４に入る圧油の量によって制限されること
となる。この結果、油圧ショベルのアーム１０の速度及
びそれに取りついＣいるパケット１１の動きが遅くなり
、作業サイクルが遅く能率が悪いと苦う欠点がある。Therefore, conventionally, in order to eliminate the above-mentioned breathing phenomenon, a throttle valve 15 is provided in the middle of the oil passage connecting the directional control valve 1 and the rod side 3 of the arm cylinder 9, and a
This hydraulic circuit slows down the expansion speed of the piston 4a to less than the speed at which the piston 14 moves when pressure oil flows into the &)m side 4, thereby preventing the above-mentioned breathing phenomenon from occurring. However, in this case, the speed of extension of the rod 14a of the arm cylinder 9 is limited by the amount of pressure oil entering the bottom side 4. As a result, the speed of the arm 10 of the hydraulic excavator and the movement of the packet 11 attached to it become slow, resulting in a slow work cycle and poor efficiency.
本発明は、上述の欠点を改善した油圧回路を提供せんと
するものである。The present invention aims to provide a hydraulic circuit which improves the above-mentioned drawbacks.
本発明は、シリンダの作動中にロッド側またはコトム側
中の油をコトム側またはロッド側に、ロッド側ｌたはボ
トム側の圧力がボトム側またはロッド側の圧力より尚く
なったとき送るようにし、息つき現象をなくし、かつシ
リンダの作動速度を早めることができることを％徴とす
る。The present invention is designed to send oil in the rod side or bottom side to the top side or rod side during operation of the cylinder when the pressure on the rod side or bottom side becomes lower than the pressure on the bottom side or rod side. The characteristics are that it can eliminate the breathing phenomenon and increase the operating speed of the cylinder.
以下、本発明の建設機械の油圧回路の一実施例を第４図
を参照して説明する。Hereinafter, one embodiment of a hydraulic circuit for a construction machine according to the present invention will be described with reference to FIG.
図中、第１図乃至第３図と同符号は同一のものを示す。In the figure, the same reference numerals as in FIGS. 1 to 3 indicate the same parts.
−しかして、この実施例における本発明の油圧回路は、
操作用の油圧ポンプ１７に第１切換弁１６を接続し、そ
の第１切換弁１６に第２切換弁１８を接続し、方向制御
弁１とアームシリンダ９のロッド側３とを結ぶ油路の途
中に第３切換弁１９を設け、その第３切換弁１９と方向
制御弁１．アームシリンダ９の＆）ム側４を結ぶ油路と
の間にパイ・やス路２６を設け、そのバイパス路かに逆
止弁２７を設ける。前記第１切換弁１６は３ボ一ト２位
置の切換弁であって、操作レバー７に連係し、操作レバ
ー７が中立位置・・および位置口乃至位置二のある範囲
以内の操作範囲においてはＡ位置に位置し、操作用の油
圧ボン７’１７からの操作用の圧油を油タンク６に戻し
、操作レバー７を位置イに操作すると、Ａ位置からＢ位
置に切換わり、操作用の油圧ポンプ１７からの操作用の
圧油を第２切侠弁１８に送るものである。- Therefore, the hydraulic circuit of the present invention in this embodiment:
A first switching valve 16 is connected to a hydraulic pump 17 for operation, a second switching valve 18 is connected to the first switching valve 16, and an oil passage connecting the directional control valve 1 and the rod side 3 of the arm cylinder 9 is formed. A third switching valve 19 is provided in the middle, and the third switching valve 19 and the direction control valve 1. A pi/spa passage 26 is provided between the arm cylinder 9 and the oil passage connecting the &) arm side 4, and a check valve 27 is provided in the bypass passage. The first switching valve 16 is a 3-bot, 2-position switching valve that is linked to the operating lever 7, and when the operating lever 7 is in the neutral position and within a certain range from position opening to position 2, When the operating pressure oil from the operating hydraulic bong 7'17 is returned to the oil tank 6 and the operating lever 7 is moved to position A, the operating lever switches from the A position to the B position. Pressure oil for operation from the hydraulic pump 17 is sent to the second valve 18.
前記第２切換弁１８は３ポ一ト２位置の切換弁であって
、アーム／リンダ９のボトム側４の圧力を・ぞイロット
圧とし、アームシリンダ９のボトム側４の圧力が低い時
においてはＡ位置に位置し第３切換弁１９に操作用の圧
油を送り、アームシリンダ９のメトム側４の圧力が所定
の圧力より上がると、Ａ位置からＢ位置に切換わり操作
用の圧油を油タンク６に戻すものである。前記第３切換
弁１９は３−一ト２位置の切換弁であって、操作用の圧
油を・ぞイロット圧とし、切換弁１６が常態Ａ位置の場
合或いは切換弁１６がＢ位置の場合で切換弁１８がＢ位
置の場合においてはＡ位置に位置し方向制御弁１とアー
ムシリンダ９のロッド側３と全連通させ、・ぞイロソト
圧がかかると、Ａ位置からＢ位置に切換わりアームシリ
ンダ９のロッド側３とバイパス路２６とを連通させる。The second switching valve 18 is a three-point/two-position switching valve, and the pressure on the bottom side 4 of the arm/cylinder 9 is the pilot pressure, and when the pressure on the bottom side 4 of the arm cylinder 9 is low, is located at the A position and sends operating pressure oil to the third switching valve 19. When the pressure on the metom side 4 of the arm cylinder 9 rises above a predetermined pressure, the switch is switched from the A position to the B position and the operating pressure oil is sent to the third switching valve 19. is returned to the oil tank 6. The third switching valve 19 is a switching valve with 3-1 to 2 positions, and the operating pressure oil is pilot pressure, and when the switching valve 16 is normally in the A position or when the switching valve 16 is in the B position. When the switching valve 18 is in the B position, it is in the A position and the directional control valve 1 is in full communication with the rod side 3 of the arm cylinder 9. When the vertical pressure is applied, the arm is switched from the A position to the B position. The rod side 3 of the cylinder 9 and the bypass passage 26 are communicated.
前記逆止弁２７はアームシリンダ９のロッド側３の圧力
がメトムＩ１１４の圧力より高くなったとき、開いてロ
ッド１ｊｌｌｊ ３中の油をボトム側４に流入をせるも
のである。The check valve 27 opens when the pressure on the rod side 3 of the arm cylinder 9 becomes higher than the pressure on the metome I 114, allowing the oil in the rod 1jllj 3 to flow into the bottom side 4.
この実施例における本発明の油圧回路は、以上の如き構
成よりなり、以下その操作について説明する。The hydraulic circuit of the present invention in this embodiment has the above configuration, and its operation will be explained below.
通常操作においては、操作レバー７を中立位置ハから二
の位置または口の位置に操作する。すると、方向制御弁
１が切換わり、油圧ボンｆ５からの圧油がアームシリン
ダ９のロッド側３またはボ１トム側４に流入してアーム
シリンダ９のピストンロッド１４ａが縮んだり筐たは伸
ひたりし、一方アームシリンダ９のボトム側４−１．た
けロッド側３の油が油タンク６に戻る。このとき、第１
切換弁１６５はＡ位置に位置するので、操作用の油圧、
Ｉ？ポンプ７からの圧油は油タンク６に戻る。即ち、操
作レバー７を口の方向に動かすことはアームシリンダ９
のロッド１４ａが伸びる方向であり、二の方向は縮む方
向である。In normal operation, the operating lever 7 is operated from the neutral position C to the second position or the opening position. Then, the directional control valve 1 is switched, and the pressure oil from the hydraulic cylinder f5 flows into the rod side 3 or bottom side 4 of the arm cylinder 9, causing the piston rod 14a of the arm cylinder 9 to contract or expand. On the other hand, the bottom side 4-1 of the arm cylinder 9. The oil on the bamboo rod side 3 returns to the oil tank 6. At this time, the first
Since the switching valve 165 is located at the A position, the hydraulic pressure for operation,
I? Pressure oil from pump 7 returns to oil tank 6. That is, moving the operating lever 7 in the direction of the mouth is done by the arm cylinder 9.
This is the direction in which the rod 14a extends, and the second direction is the direction in which the rod 14a contracts.
次に、操作レバー７をイの位置にまで操作する。Next, operate the operating lever 7 to position A.
すると、第１切挨弁１６がＡ位置からＢ位置に切換わり
、操作用の油圧ポンプ１７からの圧油が第２切換弁１８
に送らｎる。ここで、アームシリンダ９のボトム側４の
圧力が所定の圧力より高いと、第２切換弁１８はＢ位置
に位置し、第１切換弁１６から送られてきた操作用の圧
油は油タンク６に戻される。Then, the first switching valve 16 is switched from the A position to the B position, and the pressure oil from the operating hydraulic pump 17 is transferred to the second switching valve 18.
Sent to. Here, when the pressure on the bottom side 4 of the arm cylinder 9 is higher than a predetermined pressure, the second switching valve 18 is located at the B position, and the operating pressure oil sent from the first switching valve 16 is transferred to the oil tank. It will be returned to 6.
そして、アームシリンダ９のボトム側４の圧力が所定の
圧力、すなわちアームシリンダ９の負荷による移動速度
とボトム側４中に入る圧油の量が等しくなるような状態
のとき或いは負荷による移動速度が大きいときにはアー
ムシリンダ９のボトム１ｌｌｌ１４の圧力が下がり第２
切換弁１８がＢの位置からＡの位置に切換わり、操作用
の圧油が第３切換弁１９のスツール操作部に供給される
。すると、その第３切挨升１９はＡの位置からＢの位置
に切換わ抄、アームシリンダ９のロッド側３とパイノや
ス回路２６とが連通烙れる。ここで、負荷によりアーム
シリンダ９のピストン１４の動きに対してボトム側４へ
の圧油の圧力とロッド側３側の圧油の圧力を比較してロ
ッド側３側が高くなると、逆止弁２７が開キ、アームシ
リンダ９のロッド１ｌ１１３の油がバイパス路かを通っ
てボトム０Ｉ１１４に流入される。この結果、ボトム側
４中に流入される油の量が増加し、息つき現象が解消さ
れ、しかもアームシリンダ９のピストン１４の動きも早
く、従って作業サイクルも早く作業能率が良くなる。When the pressure on the bottom side 4 of the arm cylinder 9 is a predetermined pressure, that is, when the moving speed of the arm cylinder 9 due to the load is equal to the amount of pressure oil entering the bottom side 4, or when the moving speed due to the load is When the pressure is large, the pressure at the bottom 1llll14 of the arm cylinder 9 decreases and the second
The switching valve 18 is switched from position B to position A, and operating pressure oil is supplied to the stool operating portion of the third switching valve 19. Then, the third cutting section 19 is switched from the position A to the position B, and the rod side 3 of the arm cylinder 9 and the pin/slip circuit 26 are communicated with each other. Here, with respect to the movement of the piston 14 of the arm cylinder 9 due to load, the pressure of the pressure oil on the bottom side 4 and the pressure oil on the rod side 3 side are compared, and if the pressure on the rod side 3 side becomes higher, the check valve 27 is opened, and the oil in the rod 1113 of the arm cylinder 9 flows into the bottom 01114 through the bypass path. As a result, the amount of oil flowing into the bottom side 4 is increased, the breathing phenomenon is eliminated, and the piston 14 of the arm cylinder 9 moves quickly, resulting in a faster work cycle and improved work efficiency.
なお、アームシリンダ９の伸しの速度を早くすることを
欲しない時には、操作レバー７が第１切換弁１６に接す
る直前に停止するか、例かのストツノを設けるか、或い
は第３切換弁１９のスツールを押す部分の操作回路を油
タンク６に戻るようにするなどの方策が考えられる。In addition, when it is not desired to increase the speed at which the arm cylinder 9 extends, the control lever 7 should be stopped immediately before it comes into contact with the first switching valve 16, a stop horn as shown in the example should be provided, or the third switching valve 19 should be stopped. Possible measures include making the operation circuit for the part that pushes the stool return to the oil tank 6.
なお・上述の実施例においては、油圧ショベルのアーム
シリンダ９について説明したが、その他のシリンダやそ
の他の建設機械の７リングを使った油圧回路にも利用で
きる。また、上述の実施例は、シリンダの伸び動作にお
ける息つき現象ｉｌＦ消したものであるが、逆に７リン
ダの縮み動作における息つき現象を解消させるようにし
ても艮い。In the above embodiment, the arm cylinder 9 of a hydraulic excavator has been described, but the present invention can also be used for other cylinders and hydraulic circuits using seven rings of other construction machines. Further, in the above-mentioned embodiment, the breathing phenomenon ilF in the cylinder extension operation is eliminated, but conversely, it is also possible to eliminate the breathing phenomenon in the contraction movement of the 7 cylinder.
例えば、油圧７ヨペルのアームシリンダの縮み動作にお
ける息つき現象を解消をせるようにしても良い。For example, it may be possible to eliminate the breathing phenomenon in the retracting operation of the arm cylinder with a hydraulic pressure of 7 yelps.
以上の実施例からも明らかなように、本発明の油圧回路
は、息つき現象をなくし、シリンダの動きを早くでき作
業能率が向上するなどの効果がある。As is clear from the above embodiments, the hydraulic circuit of the present invention is effective in eliminating the breathing phenomenon, allowing the cylinder to move faster, and improving work efficiency.
ノ１No.1
第１図は従来の建設機械の油圧回路図、第２図は油圧シ
ョベルの側面図、第３図は油圧ショベルのフロントの側
面図、第４図は本発明の建設機械の油圧回路の一実施例
を示した油圧回路図でちる。
１・・・方向制御弁、３・・・ロッド側、４・・・はト
ム側、５・・・油圧ポンプ、６・・・油タンク、７・・
・操作レバー、９・・・アームシリンダ、１６・・・床
１切換弁、１７・・・操作用油圧ポンプ、１８・・・第
２切換弁、１９・・・第３切快弁、２６・・・バイノ々
ス路、Ｉ・・・逆止弁。
特許出願人 日立建機株式会社
代理人 弁理士 秋 本 正 実
第１図
第４ 図Fig. 1 is a hydraulic circuit diagram of a conventional construction machine, Fig. 2 is a side view of a hydraulic excavator, Fig. 3 is a front side view of the hydraulic excavator, and Fig. 4 is an implementation of the hydraulic circuit of the construction machine of the present invention. This is a hydraulic circuit diagram showing an example. 1...Direction control valve, 3...Rod side, 4...Tom side, 5...Hydraulic pump, 6...Oil tank, 7...
- Operation lever, 9... Arm cylinder, 16... Floor 1 switching valve, 17... Hydraulic pump for operation, 18... Second switching valve, 19... Third switching valve, 26. ... Binosu road, I... Check valve. Patent applicant Hitachi Construction Machinery Co., Ltd. Agent Patent attorney Tadashi Akimoto Figure 1 Figure 4
Claims (1)
ダを接続し、前記方向制御弁に操作レバーを連係し、そ
の操作レバーを操作して方向制御弁を切換え、油圧源か
らの圧油をシリンダのロッド１１１１１″ｉたはボトム
側に供給してシリンダのロッドを縮めたりまたは伸した
りし、そのシリンダのメトムｇＩｌｌまたはロッド側の
油をタンクに戻すように構成した建設機械の油圧回路に
おいて、操作用の油圧源に第１切換弁を接続し、その第
１切換弁に前記シリンダのボトム側またはロッド側の圧
力をパイロット圧とする第２切換弁を接続し、前記方向
制御弁とシリンダのロッド１４１１’Ｅたはぎトム側と
を結ぶ油路の途中に、前記操作用の油圧源からの圧油を
パイロット圧とする第３切挨弁を設け、その第３切換弁
と前記方向制御弁、シリンダの第２室を結ぶ油路との７
間にバイノ４ス路を設け、そのバイパス路に逆止弁を設
け、前記第１切換弁は前記操作レバーに連係し、その操
作レバーをある範囲以上に操作すると切換わり前記第２
切侠弁に操作用の圧油を送り、前記第２切侠弁は前記シ
リンダのｄｌトム側またはロッド側の圧力が設定圧以上
に高い時は操作用圧油はタンクに流れシリンダの２ぎト
ム側またはロッド側の圧力が設定圧以下に下がると切換
ゎり前記第３切挨弁のスツール操作部に操作用の圧油を
送り、前記第３切挨弁は前記第２切換弁からの操作用の
圧油により切換わり前記シリンダのロッド１ｕｌｌ−Ｅ
たけボトム側とパイノクス路とを連通させ、前記逆止弁
は前記シリンダのロッド側またはボトム側の圧力がボト
ム１１！Ｉ ｔたはロッド側の圧力より高くなると開き
シリンダのロッド側またはｙＮ）ム側の油がボトム側ま
たはロッド側に流入するように構成したことを特徴とす
る建設機械の油圧回路。A directional control valve is connected to a hydraulic source, a cylinder is connected to the directional control valve, an operating lever is linked to the directional control valve, the directional control valve is switched by operating the operating lever, and pressure oil from the hydraulic source is controlled. A hydraulic circuit for construction machinery configured to supply oil to the rod 11111''i or the bottom side of the cylinder to retract or expand the rod of the cylinder, and to return oil from the mettom gIll or rod side of the cylinder to the tank. , a first switching valve is connected to a hydraulic pressure source for operation, a second switching valve whose pilot pressure is the pressure on the bottom side or rod side of the cylinder is connected to the first switching valve, and the directional control valve and the second switching valve are connected to the first switching valve. A third switching valve is provided in the middle of the oil path connecting the rod 1411'E of the cylinder with the tom side, and the third switching valve uses the pressure oil from the operating hydraulic source as the pilot pressure. 7 with the oil passage connecting the control valve and the second chamber of the cylinder.
A by-pass path is provided in between, and a check valve is provided in the bypass path, and the first switching valve is linked to the operating lever, and switches when the operating lever is operated beyond a certain range.
Pressure oil for operation is sent to the control valve, and when the pressure on the DL tom side or the rod side of the cylinder is higher than the set pressure, the pressure oil for operation flows to the tank and the pressure oil is sent to the second side of the cylinder. When the pressure on the tom side or the rod side falls below the set pressure, the switching valve sends operating pressure oil to the stool operating section of the third switching valve, and the third switching valve is operated by the second switching valve. The rod 1ull-E of the cylinder is switched by the pressure oil for
The bottom side of the bamboo is communicated with the pinox passage, and the check valve allows the pressure on the rod side or bottom side of the cylinder to reach the bottom 11! 1. A hydraulic circuit for construction machinery, characterized in that when the pressure becomes higher than the pressure on the rod side, the oil on the rod side or the yN) side of the cylinder opens and flows into the bottom side or the rod side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21955183A JPS60112935A (en) | 1983-11-24 | 1983-11-24 | Hydraulic circuit of construction equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21955183A JPS60112935A (en) | 1983-11-24 | 1983-11-24 | Hydraulic circuit of construction equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS60112935A true JPS60112935A (en) | 1985-06-19 |
Family
ID=16737272
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21955183A Pending JPS60112935A (en) | 1983-11-24 | 1983-11-24 | Hydraulic circuit of construction equipment |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60112935A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0436740A1 (en) * | 1989-08-02 | 1991-07-17 | Kabushiki Kaisha Komatsu Seisakusho | Linear excavation control apparatus in hydraulic excavator |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5613418U (en) * | 1979-07-09 | 1981-02-04 | ||
| JPS57140445A (en) * | 1981-02-21 | 1982-08-31 | Hitachi Constr Mach Co Ltd | Oil-pressure circuit for oil-pressure type excavator |
-
1983
- 1983-11-24 JP JP21955183A patent/JPS60112935A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5613418U (en) * | 1979-07-09 | 1981-02-04 | ||
| JPS57140445A (en) * | 1981-02-21 | 1982-08-31 | Hitachi Constr Mach Co Ltd | Oil-pressure circuit for oil-pressure type excavator |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0436740A1 (en) * | 1989-08-02 | 1991-07-17 | Kabushiki Kaisha Komatsu Seisakusho | Linear excavation control apparatus in hydraulic excavator |
| US5598648A (en) * | 1989-08-02 | 1997-02-04 | Kabushiki Kaisha Komatsu Seisakusho | Apparatus for controlling straight excavating operation with hydraulic excavator |
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