JPH0212282B2 - - Google Patents
Info
- Publication number
- JPH0212282B2 JPH0212282B2 JP15364082A JP15364082A JPH0212282B2 JP H0212282 B2 JPH0212282 B2 JP H0212282B2 JP 15364082 A JP15364082 A JP 15364082A JP 15364082 A JP15364082 A JP 15364082A JP H0212282 B2 JPH0212282 B2 JP H0212282B2
- Authority
- JP
- Japan
- Prior art keywords
- cylinder
- pressure
- pressure chamber
- circuit
- piston
- 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.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/08—Characterised by the construction of the motor unit
- F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
- F15B15/16—Characterised by the construction of the motor unit of the straight-cylinder type of the telescopic type
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Actuator (AREA)
- Fluid-Pressure Circuits (AREA)
Description
【発明の詳細な説明】
本発明は坑道内の天盤等を支保するのに適する
流体シリンダに関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluid cylinder suitable for supporting a ceiling or the like in a mine shaft.
一般に鉱山に於いて、坑道又は作業場の天井を
油圧的又は機械的に突張つて支持する建付動作が
必要であり、従来この建付には坑道内での運搬性
や天盤高さの変化に巾広く対応させるために流体
を利用した多段シリンダによる鉄柱を使用してい
る。 In general, in mines, it is necessary to perform erection operations that hydraulically or mechanically extend and support the ceiling of a mine shaft or workshop. In order to accommodate a wide range of applications, an iron column with multi-stage cylinders using fluid is used.
即ち、従来の多段シリンダ１は基端シリンダ２
内にピストンを介して中間シリンダ４が上下摺動
自在に挿入され、又この中間シリンダ４内にピス
トン５を介して上段シリンダ６が上下摺動自在に
挿入されている。 That is, the conventional multi-stage cylinder 1 has a proximal end cylinder 2.
An intermediate cylinder 4 is vertically slidably inserted into the intermediate cylinder 4 via a piston, and an upper cylinder 6 is vertically slidably inserted into the intermediate cylinder 4 via a piston 5.
基端シリンダ２内には上下二つの圧力室ａ，ｂ
がピストン３を介して区画され、中間シリンダ４
内には同じくピストン５を介して上下二つの圧力
室ｃ，ｄが円画され、圧力室ｄ，ｂは中間シリン
ダ４の下端に設けた通孔７を介して連通してい
る。上段シリンダ６には二つの通路８，９が貫通
して設けられ、一方の通路８は圧力室ｃに開口す
ると共に回路１０を介してポンプ又はタンク等の
油圧源１１に接続され、他方の通路９は圧力室ｄ
に開口すると共に回路１２を介してポンプ又はタ
ンク等の油圧源１３に接続されている。又回路１
０から分岐した回路１４は圧力室Ａに通じてい
る。 Inside the base end cylinder 2, there are two pressure chambers, upper and lower, a and b.
is partitioned via the piston 3, and the intermediate cylinder 4
Inside, two pressure chambers c and d, upper and lower, are defined in a circular manner via the piston 5, and the pressure chambers d and b communicate with each other via a through hole 7 provided at the lower end of the intermediate cylinder 4. Two passages 8 and 9 are provided passing through the upper cylinder 6, one passage 8 opens into the pressure chamber c and is connected to a hydraulic power source 11 such as a pump or tank via a circuit 10, and the other passage 9 is pressure chamber d
The hydraulic pressure source 13 is connected via a circuit 12 to a hydraulic power source 13 such as a pump or a tank. Also circuit 1
A circuit 14 branched from 0 communicates with the pressure chamber A.
建付作業を行う場合、油圧源１３から高圧油を
導くと、この作動油は回路１２−通路９−圧力室
ｄ−通孔７より圧力室ｂに導き先ず中間シリンダ
４を伸長させ、中間シリンダ４の伸長後圧力室ｄ
の圧で上段シリンダ６が伸長し、この上段シリン
ダ６が坑道内の天盤を支える。 When performing construction work, when high-pressure oil is introduced from the hydraulic source 13, this hydraulic oil is introduced into the pressure chamber b through the circuit 12, the passage 9, the pressure chamber d, and the through hole 7, and first extends the intermediate cylinder 4. Pressure chamber d after extension of 4
The upper cylinder 6 expands under the pressure of , and this upper cylinder 6 supports the ceiling in the tunnel.
ところで上記多段シリンダ１からなる鉄柱を坑
道内に突張つて建付けた時のイニシヤル荷重たる
建付荷重は上段シリンダ６が担持し、この時、中
間シリンダ４のピストン受圧面をD1、上段シリ
ンダ６のピストン受圧面をD2とした時、上記建
付荷重は「ポンプ圧力×D2面積」となる。従つ
て建付荷重はポンプ圧力が一定で受圧面積D2も
一定の場合には大きな建付荷重が得られない。 By the way, when the steel column consisting of the multi-stage cylinder 1 is extended and erected in a mine shaft, the initial load or erection load is carried by the upper stage cylinder 6. At this time, the piston pressure receiving surface of the intermediate cylinder 4 is D1 , and the upper stage cylinder is When the piston pressure receiving surface of No. 6 is D2 , the above installation load is "pump pressure x D2 area". Therefore, when the pump pressure is constant and the pressure receiving area D2 is also constant, a large erection load cannot be obtained.
即ち建付荷重を増したい場合はポンプ圧力を上
げるか又は受圧面積D2を大きくするより方法が
なく、予めポンプ圧力が決まつているような場
合、大きな建付荷重を要求される時には受圧面積
D2を大きくするしかない。しかし受圧面積D2を
大きくすると流体シリンダが大形となつてしまい
重量アツプ、コストアツプとなり、又運搬時に不
利である。 In other words, if you want to increase the erection load, there is no other way than to increase the pump pressure or increase the pressure receiving area D2.If the pump pressure is predetermined, and a large erection load is required, the pressure receiving area D2 must be increased.
The only option is to increase D2 . However, increasing the pressure receiving area D2 increases the size of the fluid cylinder, which increases weight and cost, and is disadvantageous during transportation.
従つて本発明の目的は、シリンダ径を大きくす
ることなく又ポンプ圧力を上げることもなくして
建付荷重を大きくすることができる坑道内の天盤
を支保する鉄柱用に好適な流体シリンダを提供す
ることである。 SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fluid cylinder suitable for an iron column supporting a ceiling in a mine shaft, which can increase the erection load without increasing the cylinder diameter or increasing the pump pressure. It is to be.
本発明はこの目的達成の為、基端シリンダ側の
圧力室と中間シリンダ側の圧力室を隔離して圧油
を独立して給排させ、これにより建付荷重を受圧
面積の大きい圧力室で担持させるようにしたこと
を特徴とするものである。 In order to achieve this objective, the present invention isolates the pressure chamber on the base end cylinder side and the pressure chamber on the intermediate cylinder side and supplies and discharges pressure oil independently, thereby handling the erection load in the pressure chamber with a large pressure receiving area. It is characterized in that it is supported.
以下本発明の実施の態様を第１〜第４図面につ
いて説明する。 Embodiments of the present invention will be described below with reference to the first to fourth drawings.
第２図は本発明の好適な一実施例に係る流体シ
リンダとその回路図である。即ち、多段シリンダ
２１は基端シリンダ２２内にピストン２３を介し
て中間シリンダ２４が上下摺動自在に挿入され、
又この中間シリンダ２４内にピストン２５を介し
て上段シリンダ２６が上下摺動在に挿入されてい
る。 FIG. 2 is a fluid cylinder and its circuit diagram according to a preferred embodiment of the present invention. That is, in the multistage cylinder 21, an intermediate cylinder 24 is inserted into a base end cylinder 22 via a piston 23 so as to be vertically slidable.
Further, an upper stage cylinder 26 is inserted into the intermediate cylinder 24 via a piston 25 so as to be vertically slidable.
基板シリンダ２２内には上下二つの圧力室Ａ，
Ｂがピストン２３を介して区画され、中間シリン
ダ２４内には同じくピストン２５を介して上下二
つの圧力室Ｃ，Ｄが区画されている。上段シリン
ダ２６には二つの通路２８，２９が貫通して設け
られ、一方の通路２８は圧力室Ｃに開口すると共
に回路３０を介してポンプ又はタンク等の油圧源
３１に接続され、他方の通路２９は圧力室Ｄに開
口すると共に回路３２を介してポンプ又はタンク
等の油圧源３３に接続されている。又回路３０か
ら分岐した回路３４は圧力室Ａに通じている。 Inside the substrate cylinder 22, there are two pressure chambers A, upper and lower.
B is divided by a piston 23, and the intermediate cylinder 24 is also divided by a piston 25 into two upper and lower pressure chambers C and D. Two passages 28 and 29 are provided passing through the upper cylinder 26, one passage 28 opens into the pressure chamber C and is connected to a hydraulic source 31 such as a pump or a tank via a circuit 30, and the other passage 29 opens into the pressure chamber D and is connected via a circuit 32 to a hydraulic source 33 such as a pump or a tank. Further, a circuit 34 branched from the circuit 30 communicates with the pressure chamber A.
又回路３２から分岐した分岐回路３５は圧力室
Ｂに接続されている。 Further, a branch circuit 35 branched from the circuit 32 is connected to the pressure chamber B.
回路３２中はチエツクバルブ３６とリリーフバ
ルブ３７が設けられ、他方の分岐回路３５中にも
チエツクバルブ３８とリリーフバルブ３９が介装
され、一方のチエツクバルブ３６は回路３０から
のパイロツト圧で開き、同じく他方のチエツクバ
ルブ３８は回路３４のパイロツト圧で開くように
されている。 A check valve 36 and a relief valve 37 are provided in the circuit 32, and a check valve 38 and a relief valve 39 are also provided in the other branch circuit 35, and one check valve 36 is opened by the pilot pressure from the circuit 30. Similarly, the other check valve 38 is opened by the pilot pressure of the circuit 34.
チエツクバルブ３６と３８はそれぞれ開弁圧が
異なり、チエツクバルブ３６が先に開き、上段シ
リンダ２６が最伸し、圧力室Ｄの内圧が上昇して
からチエツクバルブ３８が開くようになつてい
る。 The check valves 36 and 38 have different opening pressures, so that the check valve 36 opens first, the upper cylinder 26 is fully extended, and the internal pressure of the pressure chamber D rises before the check valve 38 opens.
上記流体シリンダ２１からなる鉄柱で坑道内の
建付作業を行う場合、圧力源３３がポンプ側に、
他方の圧力源３１をタンク側に接続し、回路３２
に高圧油を供給する。この時チエツクバルブ３６
が開き、高圧油は通路２９より圧力室Ｄに導か
れ、ピストン２５の受圧面D3に作用する圧力で
上段シリンダ２５が伸長し、この時圧力室Ｃの作
動油は通路２８−回転３０を介して圧力源３１に
排出される。上段シリンダ２６が最伸長になる
と、圧力室Ｄはチエツクバルブ３６で逆流が遮断
され、リリーフバルブ３７のリリーフセツト圧力
迄は密閉された状態になる。一方この上段シリン
ダ２６の伸長後チエツクバルブ３８が開き、圧力
源３３の高圧油は回路３５を介して圧力室Ｂに導
かれ、ピストン２３の受圧面積D4に作用する圧
力で中間シリンダ２４が伸長し、建付荷重は圧力
室Ｂで担持する。この場合建付荷重は「ポンプ圧
力×受圧面積D4」であり、ポンプ圧力が従来と
同じように一定であつても受圧面積として大きい
方（D4＞D3）が使用されるから大きな建付荷重
が得られるものである。 When performing erection work in a mine shaft using a steel pole consisting of the fluid cylinder 21, the pressure source 33 is placed on the pump side.
The other pressure source 31 is connected to the tank side, and the circuit 32
Supply high pressure oil to. At this time, check valve 36
opens, high-pressure oil is guided from the passage 29 to the pressure chamber D, and the upper cylinder 25 expands due to the pressure acting on the pressure-receiving surface D3 of the piston 25. At this time, the hydraulic oil in the pressure chamber C is guided from the passage 28 to the rotation 30. It is discharged to the pressure source 31 through the pressure source 31. When the upper stage cylinder 26 reaches its maximum extension, the check valve 36 blocks backflow from the pressure chamber D, and the pressure chamber D remains sealed until the pressure reaches the relief set pressure of the relief valve 37. On the other hand, after the upper stage cylinder 26 is extended, the check valve 38 is opened, and the high pressure oil from the pressure source 33 is guided to the pressure chamber B via the circuit 35, and the intermediate cylinder 24 is extended by the pressure acting on the pressure receiving area D 4 of the piston 23. However, the erection load is carried by pressure chamber B. In this case, the construction load is "pump pressure x pressure receiving area D 4 ", and even if the pump pressure is constant as in the past, the larger pressure receiving area (D 4 > D 3 ) is used, so it is difficult to build a large building. An additional load can be obtained.
尚圧縮作動時には圧力源３１より高圧を導き、
他の圧力源３３をタンク側に接続する。この時回
路３０より高圧が通路２８より圧力室Ｃに導か
れ、又回路３４より同じく高圧が圧力室Ａに導か
れる。又同時に回路３０，３４のパイロツト圧で
チエツクバルブ３６，３８が開くから圧力室Ｄ，
Ｂの圧油は回路３２，３８を介して低圧側に排出
されるから各シリンダ２４，２６は圧縮する。 In addition, during compression operation, high pressure is introduced from the pressure source 31,
Another pressure source 33 is connected to the tank side. At this time, high pressure is introduced from the circuit 30 to the pressure chamber C through the passage 28, and high pressure is similarly introduced from the circuit 34 to the pressure chamber A. At the same time, check valves 36 and 38 are opened by the pilot pressure of circuits 30 and 34, so pressure chambers D and
Since the pressure oil B is discharged to the low pressure side via the circuits 32 and 38, each cylinder 24 and 26 is compressed.
第３図、第４図は実際に使用される鉄柱の一実
施例に係るものである。便宜上同じ構成部材は第
２図のものと同じ符号を使用する。 FIGS. 3 and 4 show an example of a steel pole that is actually used. For convenience, the same components are designated by the same reference numerals as in FIG.
基端シリンダ２２内にピストン２３とベアリン
グ２３ａを介して中間シリンダ２４が摺動自在に
挿入され、基端シリンダ２２内にはピストン２３
によつて二つの圧力室Ａ，Ｂが区画されている。 An intermediate cylinder 24 is slidably inserted into the base end cylinder 22 via a piston 23 and a bearing 23a, and the piston 23 is inserted into the base end cylinder 22.
Two pressure chambers A and B are partitioned by.
中間シリンダ２４内にはピストン２５とヘツド
２５ａを介して上段シリンダ２６が摺動自在に挿
入され、中間シリンダ２４内にはピストン２５を
介して圧力室Ｃ，Ｄが区画されている。基端シリ
ンダ２２の上下にはボトム４０とヘツド４１が溶
接等で固定され、ヘツド４１の内側にはワツパリ
ング５０とシールアツセンブリ５１が介装され、
又基端シリンダ２２の下部外周には圧力室Ｂに開
口するポート４２が設けられ、このポート４２は
第２図と同じ回路３５が接続されるようになつて
いる。 An upper cylinder 26 is slidably inserted into the intermediate cylinder 24 via a piston 25 and a head 25a, and pressure chambers C and D are defined within the intermediate cylinder 24 via the piston 25. A bottom 40 and a head 41 are fixed to the top and bottom of the base end cylinder 22 by welding or the like, and a watz ring 50 and a seal assembly 51 are interposed inside the head 41.
Further, a port 42 that opens into the pressure chamber B is provided on the lower outer periphery of the base end cylinder 22, and the same circuit 35 as shown in FIG. 2 is connected to this port 42.
中間シリンダ２４は上下にヘツド２５ａとボト
ム４３が設けられ、ボトム４３の外周にピストン
２３とホルダ４４が保持され、ピストン２３の外
周にはピストンリング４５とシールアツセンブリ
４６が設けられている。中間シリンダ２４のボト
ム２５ａ内側にはパツキンヘツド４７とワツパリ
ング４８とシールアツセンブリ４９が介装されて
いる。 The intermediate cylinder 24 is provided with a head 25a and a bottom 43 on the upper and lower sides, a piston 23 and a holder 44 are held on the outer periphery of the bottom 43, and a piston ring 45 and a seal assembly 46 are provided on the outer periphery of the piston 23. A packing head 47, a wafer ring 48, and a seal assembly 49 are interposed inside the bottom 25a of the intermediate cylinder 24.
上段シリンダ２６の上下にはヘツド５２とボト
ム５３が設けられ、又ピストン２５の外周にはピ
ストンリング５４と、シールアツセンブリ５５が
設けられている。 A head 52 and a bottom 53 are provided above and below the upper cylinder 26, and a piston ring 54 and a seal assembly 55 are provided around the outer periphery of the piston 25.
基端シリンダ２４の上部外周にはポート５６が
設けられ、このポート５６は圧力室Ａを第２図の
回路３４に接続されている。 A port 56 is provided on the upper outer periphery of the proximal end cylinder 24, and this port 56 connects the pressure chamber A to the circuit 34 of FIG. 2.
上段シリンダのヘツド５２とボトム５３間には
二つの通路２８，２９に対する管体５７，５８が
架設され、一方の管体５７の一側はボトム５３側
のポート８９を介して圧力室Ｃに開口し、他側ヘ
ツド５２側のポート６０，６１を介して第２図の
回路３０に通じている。又他方の管体５８の一側
はボトム５３に設けた筒体６２を介して圧力室Ｄ
に開口し、他側はヘツド５２に設けたポート６
３，６４を介して第２図の回路３２に接続してい
る。 Pipe bodies 57 and 58 for two passages 28 and 29 are installed between the head 52 and the bottom 53 of the upper cylinder, and one side of the pipe body 57 opens into the pressure chamber C through a port 89 on the bottom 53 side. However, it communicates with the circuit 30 in FIG. 2 via ports 60 and 61 on the other head 52 side. One side of the other tube 58 is connected to the pressure chamber D via a tube 62 provided on the bottom 53.
The other side is opened to the port 6 provided in the head 52.
3 and 64 to the circuit 32 of FIG.
ヘツド５２には水平方向にロツド６４が貫通し
て保持されている。 A rod 64 extends horizontally through the head 52 and is held therein.
第３図の鉄柱の作動は第２図の場合と全く同じ
である。 The operation of the steel column in FIG. 3 is exactly the same as in FIG.
以上のように本発明は二つの圧力室Ｂ，Ｄを隔
離し、それぞれの圧力室Ｂ，Ｄに圧油を独立して
給排させ、建付荷重は圧受圧面積の大きい圧力室
Ｂを利用して担持させた為に、大きな建付荷重が
必要な場合でもわざわざ大きい受圧面積を得るた
めにシリンダ径を大きくする必要がなく、従来と
同じタイプのシリンダを使用出来るから重量も軽
く、コストダウンを計れ、運搬作業も容易であ
る。 As described above, the present invention isolates two pressure chambers B and D, supplies and discharges pressure oil to each pressure chamber B and D independently, and utilizes pressure chamber B, which has a large pressure receiving area, for the construction load. Because it is supported by a large construction load, there is no need to enlarge the cylinder diameter to obtain a large pressure-receiving area, and the same type of cylinder as before can be used, which reduces weight and costs. It is easy to measure and transport.
尚本発明の流体シリンダは天盤支保用の鉄柱の
みならず、他の同様のものにも使用されることか
いうまでもない。 It goes without saying that the fluid cylinder of the present invention can be used not only for an iron column for supporting a ceiling plate, but also for other similar items.
第１図は従来の流体シリンダの略示縦断正面
図、第２図は本発明に係る流体シリンダの縦断正
面図、第３図は本発明の一実施態様に係る流体シ
リンダの縦断正面図、第４図は第３図の−線
横断平面図である。
２２……基端シリンダ、２４……中間シリン
ダ、２３……ピストン、２５……ピストン、２６
……上段シリンダ、３０，３４……回路、３２，
３５……回路、３６，３８……チエツクバルブ、
３７，３９……リリーフバルブ、Ａ，Ｂ……圧力
室、Ｃ，Ｄ……圧力室。
FIG. 1 is a schematic longitudinal sectional front view of a conventional fluid cylinder, FIG. 2 is a longitudinal sectional front view of a fluid cylinder according to the present invention, and FIG. 3 is a longitudinal sectional front view of a fluid cylinder according to an embodiment of the present invention. FIG. 4 is a plan view taken along the - line in FIG. 3. 22... Proximal cylinder, 24... Intermediate cylinder, 23... Piston, 25... Piston, 26
...Upper cylinder, 30, 34...Circuit, 32,
35...Circuit, 36, 38...Check valve,
37, 39... Relief valve, A, B... Pressure chamber, C, D... Pressure chamber.
Claims (1)
介して摺動自在に挿入され、基端シリンダ内には
このピストンを介して上下二つの圧力室が区画さ
れ、中間シリンダ内には上段シリンダがピストン
を介して摺動自在に挿入され、中間シリンダ内に
は基端シリンダ側圧力室と独立した上下二つの圧
力室が上段シリンダのピストンを介して区画さ
れ、基端シリンダ側下方圧力室と中間シリンダ側
下方圧力室には圧力源からの回路を連通すると共
に、当該回路中にチエツクバルブを介装し、前記
基端シリンダの下方圧力室に通じる回路中のチエ
ツクバルブに対して中間シリンダの下方圧力室に
通じる回路中のチエツクバルブが先に開くような
開弁圧に設定してなる流体シリンダ。1. An intermediate cylinder is slidably inserted into the base end cylinder via a piston, and the base end cylinder is divided into two upper and lower pressure chambers via this piston. Inside the intermediate cylinder, two pressure chambers, upper and lower, which are independent of the pressure chamber on the proximal cylinder side, are partitioned via the piston of the upper cylinder, and a lower pressure chamber on the proximal cylinder side and a lower pressure chamber on the intermediate cylinder side. A circuit from a pressure source is connected to the lower pressure chamber, and a check valve is interposed in the circuit, so that the check valve in the circuit communicating with the lower pressure chamber of the base end cylinder is connected to the lower pressure chamber of the intermediate cylinder. A fluid cylinder whose opening pressure is set so that the check valve in the circuit leading to the valve opens first.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15364082A JPS5943206A (en) | 1982-09-03 | 1982-09-03 | Fluid cylinder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15364082A JPS5943206A (en) | 1982-09-03 | 1982-09-03 | Fluid cylinder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5943206A JPS5943206A (en) | 1984-03-10 |
| JPH0212282B2 true JPH0212282B2 (en) | 1990-03-19 |
Family
ID=15566932
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15364082A Granted JPS5943206A (en) | 1982-09-03 | 1982-09-03 | Fluid cylinder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5943206A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3816092C2 (en) * | 1987-05-28 | 1996-12-05 | Noell Serv & Maschtechn Gmbh | Hydraulic lifting cylinder |
| JPH0716707Y2 (en) * | 1989-06-05 | 1995-04-19 | 飛島建設株式会社 | Telescopic jack |
| FR2659398B1 (en) * | 1990-03-06 | 1992-07-10 | Ppm Sa | MULTIPLE JACK, CIRCUIT FOR SUPPLYING SUCH A JACK, AND TELESCOPIC BOOM USING THE JACK. |
| US5613418A (en) * | 1992-03-25 | 1997-03-25 | Man Gutehoffnungshutte Aktiengesellschaft | Multiple-stage hydraulic cylinder |
| AU666004B2 (en) * | 1992-06-09 | 1996-01-25 | Gradash Pty Ltd | Heavy equipment jack |
| CN101806315B (en) * | 2010-04-07 | 2012-03-14 | 中联重科股份有限公司 | Compound Oil Cylinder and Its Garbage Compressor |
| CN102182718B (en) * | 2011-05-10 | 2013-05-01 | 上海交通大学 | Miniature triggered binary actuation pneumatic unit |
-
1982
- 1982-09-03 JP JP15364082A patent/JPS5943206A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5943206A (en) | 1984-03-10 |
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