JPS584132B2 - Power shovel actuation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power shovel, and more particularly to a power shovel actuating device with improved operating efficiency.

Conventional power excavators have a main frame rotatably attached to the tracked vehicle, a front end structure including a dipper attached to the main frame, and a dipper attached to the main frame and linked to the front end structure to remove the material being excavated. A device is provided for pushing into the pile and for lifting a dipper normally attached to the main frame and coupled to the forward end structure.

The operation of such excavators consumes a considerable amount of energy, a significant portion of which is wasted.

It has been found desirable to provide a power excavator that reduces energy consumption without reducing the work performed by the machine, thus increasing the operating efficiency of the excavator.

It is an object of the invention to reduce the energy input required for the work performed by the machine without sacrificing the work output, thus increasing the working efficiency of the excavator and making it relatively simple and reliable in design. An object of the present invention is to provide a novel power shovel working device with high performance.

The present invention also provides a power supply system which requires relatively small energy input without reducing work output, and where the weight of the functional part is loaded centrally on the main frame so that the main frame stress in response to the load is uniform throughout the main frame. An object of the present invention is to provide an actuating device for a front end structure of an excavator.

The structure of the present invention will be made clear in the following examples together with the accompanying drawings.

The power excavator shown in FIG. 1 generally includes a tracked vehicle 11, a main frame 12 rotatably mounted on the tracked vehicle, a leg (vertical jib) 13, and a substantially inverted triangular hoist pivoted to the upper end of the stiff leg 13. The frame 14, the date pad pivot arm (
(hereinafter referred to as Daytsupa arm) 15 (however, Daytsupa arm 15 may be pivoted to hoist frame 14),
A day spa 16 is pivotally connected to the outer end of the day spa arm 15, a hoist link 17 is pivotally connected to the hoist frame 14 and the day spa 16, a day spa pushing device 33 is attached to the main frame 12 and interlocks the hoist frame 14, and the day spa is attached to the main frame 12. mounted and hoist frame 14
It consists of a hoist mechanism 19 that interlocks the.

Track vehicle 11 is fitted with a lower frame 20 supporting roller seats 21 in a conventional design.

The upper frame 22 is placed on the roller seat 21 and rotatably supports the main frame 12.

The mechanism for propulsion of the tracked vehicle 11 and rotation of the upper frame 12 is housed in a cab housing 23 on the main frame 12 which also houses other mechanisms and components for operating the shovel, as described below.

The lower end of the stiff leg 13 is pivotally connected to the main frame 12 by a pair of bifurcated legs and a pair of leg pins, as is known in the art.
This allows the stiffener 13 to pivot vertically.

A head shaft 24 is provided at the upper end of the stiff leg 13,
In addition to this, the date support arm 15 and the hoist frame 14
Various components including the following are pivotally connected.

The date spar arm 15 generally consists of a pair of laterally spaced, longitudinally disposed beams that are pivotally connected at their outer ends to the side walls of the day spar 16 and interconnected along their lengths by place members. and its upper end is pivotally connected to the head shaft 24.

The hoist frame 14 has a substantially inverted triangular shape, and includes a base member 25 pivotally connected to the head shaft 24, and a column member 26 arranged diagonally with respect to the base member 25 and whose lower end is integrally connected to the front end of the base member 25. and a tension member 27 that integrally connects the upper end of the column member 26 and the rear end of the base member 25.

In another embodiment of the hoist frame in which the upper end of the date spa arm 15 is pivotally connected to the hoist frame 14, the front end of the base member 25 is bifurcated to provide a pair of forwardly protruding arms, and the upper end of the date spa arm 15 is pivotally attached to this. do.

As shown in FIG. 1, a shaft 28 is provided at the rear end of the base member 25, and a hoist sheave 29 of a hoist mechanism 19 for moving the hoist frame 14 is rotatably mounted thereon as described later.

Further, a connecting pin 30 for connecting the pushing device 33 to the hoist frame 14 is attached to the base member 25 at an intermediate position between the head shaft 24 and the hoist sheave support shaft 28.

Day spa 16 is of conventional construction, including a pair of laterally spaced side walls, a bottom wall, a plurality of digging teeth removably attached to the front lip of the bottom wall, and an upper end pivotally connected to the side wall of the day spa. It consists of a releasable door.

The date pad normally pitches upward, and this upward pitch is limited by a pitch stopper 31 attached to the upper side of the date pad arm 15.

The pitch stop collar 31 consists of a pair of beams attached to the day stopper arm 15 at an angle.

As is known in the art, the lower end of the pitch stopper is engageable with an abutment pad 32 secured to the side wall of the dispenser adjacent to the pivot point between the dispenser 16 and the hoist link 17.

As shown in FIGS. 2 to 5, the push-in device 33 of the pusher is connected to a movable mast 35 and the upper end of the movable mast 35.
The hoisted frame 1 is connected via a pair of connecting links 36 and 37.
It is connected to the base member 25 of No. 4.

The movable mast 35 has a pair of leg sections 42, 43 whose lower ends are pivotally supported by brackets 46, 47 fixed to the deck 48 of the main frame 12 and heavy bins 44, 45 in front of the rotation center lines O, L of the main frame 12. , and upper and lower crossbars 49,5 interconnecting the leg sections between their upper and lower ends.
Consists of 0.

A connecting pin 55 with a spacer 56 is mounted between the upper ends of the leg sections 42, 43.

As shown in FIGS. 1 and 4, the connecting links 36,
The rear end of 37 is pivotally connected to a connecting pin 55 between the spacer 56 and the upper end of the leg section 42.43, and its front end is pivotally connected to the base member 25 of the hoist frame 14 by an axis 30, so that the movable mast 35 When rotating about the connecting pins 44, 45 on the deck 48, this movement is transmitted to the hoist frame 14 via the connecting links 36, 37 and thus the stiff leg 13, the hoist frame 14, the deck paddle arm 1
5, transmitted to the front end structure 10 including the date pad 16 and the hoist link 17.

The pushing mechanism of the mast 35 is connected to the deck 12 at the working ends of a pair of working cylinder structures 90 and 91, which are oriented upward after the lower ends are pivoted to the brackets 107 on the deck 12, as shown in FIG. The upper end of a support link 39 in a forward tilted position is pivotally supported by a hanging bracket 57 provided, and the upper end and the movable mast 35 are connected by an operating link 41.

In detail, as shown in FIG. 3, several pairs of hanging mounting plates 57 and 58 are provided at the rear of the roller seat 21 on the deck of the main frame 12 and are spaced laterally, each of which has a support shaft 596.
0 is installed, and these support shafts have rods 6 passing through them.
The axis center is aligned by 1.

The lower end of the support link 39 includes a pair of depending plates 62, 63 extending through holes in the deck 48, which plates are pivotally connected to the support shaft 59.

At the upper end of the support link 39 is a pair of laterally arranged plates 6.
4, 65 and a bridging plate 70 protruding rearward from these plates.
horizontally aligned short plates 66, 67, interconnected by
68 and 69 are installed, and connecting pin structures 71 are attached to the short plates 66 to 69.

The connecting pin structure 71 includes a holding pin 72, an inner push 73 attached to the pin 72, a pair of spacers 74, 75 also attached to the pin 72, and a pair of spacers 74, 75 and a pair attached to the outer ends of the push 73. an outer push 73, a pair of retaining plates 78, 79 that accommodate the outer ends of the retaining pins and engage the outer ends of the pushes 76, 77, and retaining plates 7B, 79 that are threaded onto the outer ends of the pins 72; It consists of a pair of nuts that engage with.

The support link 39 has a similar structure, and a plate 69 of the support link 38 and the link 39 and a plate 69a of the link 38 are interconnected by a cross member 80.

The push-in actuation link 41 is pivotally connected to the connecting pin 54 at its front end and to the connecting pin structure 71 at its rear end.

The structure and function of the push-in actuating link 40 are similar to the actuating link 41.

In FIG. 1, reference numeral 82 indicates a fixture attached to the outer end of the connecting pin 52, and reference numeral 83 indicates a support plate 83 for reinforcing the bearing portion formed at the rear end of the link 41.

The support plate 83 is accommodated between the plates 66 and 67, 68 and 69, respectively, and the connecting pin structure 71 has an outward push 7.
A pair of laterally spaced rearwardly protruding mounting plates 84, 85 are fixedly attached to the mounting plates 6, 77.

The links 40, 41 are reinforced by a cross member 86, a cross member 87 whose ends are fixed to the mounting plates 85, 85a, and a pair of places 88, 89 when viewed from the plane of FIG.

In the upper part of FIG. 6, the pressurized fluid supply device 34 for the actuating cylinder structures 90, 91 connecting between the main frame 12 and the dipper pushing device 33 is shown.

The working cylinder structure 90 with support legs 93 consists of a fixed piston 94 in the cylinder and a movable cylinder 95 mounted on the fixed piston 94 in the cylinder 90 and having a connecting bracket 96 at its upper end.

As shown, a cylinder 90, a fixed piston 94, and a movable cylinder 95 have a variable volume chamber 97 communicating with a port 99 via a passage 98 of the fixed piston 94, a variable volume chamber 100 communicating with a port 101, and a variable volume chamber 97 communicating with a port 103. A volume chamber 102 is formed.

The movable cylinder 95 is designed such that the annular surface 104 is substantially equal to the area 105 of the end face of the fixed piston 94 .

Another working cylinder structure 91 is similar to the working cylinder structure 90 and is provided with a cylinder 91 with a support leg 93a and a fixed piston 94a, and a movable cylinder 95a with a connecting bracket 96a, and with a passage 98a. A variable volume chamber 97 communicates with port 99a through
a, a variable volume chamber 100a1 communicating with the boat 101a and a variable volume chamber 102a communicating with the port 103a.

As shown in FIGS. 2 to 4, the support legs 93, 93a of the actuating cylinder structures 90, 91 are attached to connecting pins 10 mounted on brackets 107, 107a on the deck 48.
6,106a.

connection bracket 96 of the cylinder structures 90, 91;
96a is the push 73 of the connection pin structure 71, 71a,
73a.

The brackets 107, 107a are longitudinally attached to the main frame deck substantially at the center of rotation of the main frame 12.

This causes forces generated along the centerline of the actuating cylinder structures 90, 91 to be imposed longitudinally on the main frame 12 at a point adjacent to the main frame's center of rotation, thus minimizing bending moments in the main frame 12. Close.

The fluid supply circuit 92 includes a two-way variable displacement main pump 108 and a one-way replenishment pump 1 driven by a prime mover 110.
It is activated by 09.

One port of the main pump 108 is a fluid supply pipe 111,1
12 to the ports 99 of the actuating cylinder structures 90, 91.
, 99a.

Similarly, the other ports of main pump 108 are connected to fluid supply pipe 11.
3, 114 to the ports 101, 101a of the working cylinder structures 90, 91.

Therefore, by operating the main pump 108 in either direction, pressure fluid is supplied to the chambers 97, 97a to advance the movable cylinders 95, 95a or to move the chambers 100, 10
0a to retract the movable cylinder.

Hot oil can be removed from the fluid supply pipe 11L113 by fluid pipes 115, 116 connecting the fluid supply pipes 111, 113 to a shuttle relief valve 117 which is connected to a reservoir 118 by a discharge pipe 119.

The shuttle relief valve 117 is connected to the fluid supply pipes 111, 11
3 in response to pressure within the fluid supply tube to selectively remove oil from the fluid supply tube.

The replenishment pump 109 supplies enough oil into the supply pipes 111, 113 to prevent cavitation.

The inlet port of pump 109 is connected to fluid reservoir 118 by fluid line 120, and the outlet port thereof is connected to fluid line 120.
1 to the reservoir 11B.

A predetermined pressure is maintained in the fluid pipe 121 by the relief valve 122 .

The fluid pipe 121 is also connected to the fluid supply pipes 111, 113 by pipes 127, 128 provided with relief valves 129, 130 that respond to the pressure inside the fluid supply pipes 111, 113.

In operation, the main pump 108 and the make-up pump 109
is driven and a predetermined pressure determined by the relief valve 122 is present in the pipe 121, the pressure fluid passes through the check valve 125 or 126 of either of the branch pipes 123, 124 to drain the fluid in the fluid supply pipes 111, 113. compensate.

However, at this time, the pressure inside the pipes 111 and 113 is
The pressure is below a second pressure that is lower than the pressure sufficient to open the opening.

Further, when the pressure inside the fluid supply pipes 111, 113 exceeds a predetermined pressure determined by the relief valves 129, 130, the fluid is transferred to the branch pipes 127, 12 including the relief valves 129, 130.
8 and into the reservoir 118 through a fluid line 121 that includes a relief valve 122 .

Momentary replenishment demands due to compression of the working fluid and increases in load pressure that are much greater than what the replenishment pump 109 can supply are met by at least one gas compression type accumulator communicating with the fluid conduit 121 via conduit 134. 133.

Furthermore, when the load is suddenly released, the fluid in the fluid supply pipe is suddenly released from compression, and the instantaneous flow velocity passing through the shuttle relief valve 117 increases. Check valve 1 to connect
A fluid conduit 135 with 36 is provided to store a portion of the fluid's energy in accumulator 133 in case of replenishment requirements.

During various periods of the drilling cycle, as described below, oil removed from the fluid supply pipes 111, 113 through the shuttle relief valve 117 and oil lost due to internal leakage is transferred to the replenishment pump 1.
09.

Additionally, the requirement for instantaneous replenishment is met by a high instantaneous flow rate through the shuttle relief valve 117 due to a rapid depressurization of the fluid in the system causing a sudden release of the load, or by the pressure accumulator 133 being built up by the replenishment pump 109. .

A circuit for regenerating the energy of the pressure fluid when it is activated is connected to the variable volume chamber 102 by upper fluid pipes 138 and 139 in FIG.
, 102a;
Fluid pipes 138, 139 connect this pressure accumulator with holes 103, 103a of working cylinder structures 90, 91.

Fluid line 138 includes a solenoid-operated shutoff valve 140 which is connected to reservoir 118 via branch lines 141, 142 with relief valves 143, 144 in the opposite line of shutoff valve 140.

Further, the pressure accumulator 137 is communicated with the reservoir 118 via a pipe 145 equipped with a check valve 146 .

In the above circuit, when the cutoff valve 140 is opened and the movable cylinders 95, 95a are moved back, the chambers 102, 102
It will be appreciated that the fluid released from a flows through the tubes 138, 139 to accumulate pressure in the accumulator 137.

The pressure supplied by the pressure accumulator 137 counteracts the force retracting the movable cylinder and thus in turn moves the movable cylinder 9
5,95a, reducing the energy requirements of the prime mover 110 that serves to advance the 5,95a.

To lock the movable cylinders 95, 95a in position, simply close the valve 140 to stop fluid in the chambers 102, 102a.

When valve 140 is closed, excess pressure in tubes 138, 139 between valve 140 and working cylinder structures 90, 91 can be removed by relief valve 143.

In FIG. 1, the hoist mechanism 19 is of a conventional design, and generally includes a hoist drum (not shown) attached to the main frame in the operator's cab, its drive device, a sheave 147 at the front of the operator's cab, and a sheave 147 at the rear end of the hoist frame. Sheave 29,
and a hoist line 148 that interlocks the hoist drum and the sheaves 147, 29.

As is conventional, when the hoist line 148 is extended or retracted, the hoist frame 14, and therefore also the day spa arm 15, day spa 16, and hoist link 17, are pivoted about the head shaft 24 mounted on the upper end of the stiffener leg 13.

During the pushing period of the excavator's excavation cycle, Daytsupa 16
The pitch of is stiff leg 13 and date spa arm 1.
A pair of pantograph link devices 14 attached to both sides of 5
9. A date pump pitch control device consisting of a pair of sheaves 150 attached to leg bins (not shown) connecting the lower ends of the stiff legs to the main frame 12 of the excavator, and a pair of working cylinder structures 151 with cylinders fixed to the main frame. Therefore, it can be maintained constant with respect to the main frame 12.

The structure and operation of these pantograph link devices 149 are conventional.

As shown in FIG. 1 and in detail in U.S. Pat. No. 3,501,034 and U.S. Pat. A pitch line 153 is connected to the front end of the crank, wrapped around a sheave 150 and has its other end connected to the piston portion of the cylinder structure 151, and has one end connected to a rearward point on the pitch belt crank and the other end connected to the day pad. It consists of a pitch line 154 connected to the side wall of the
Publication No. 5).

The dipper pitch control device described above has a cylinder structure 15.
When the piston of 1 is free-floating, it acts to change the pitch of the dipper 16 in response to forces imposed by the dipper's own weight or by contact of the dipper with the ground or material being excavated.

However, when the piston of the cylinder structure 151 is locked, the pantograph linkage 149 fixes the pitch of the dipper until the piston is released and becomes free floating again.

In operating the above-described embodiment, the front end structure 1 of the jobvel
0 at the beginning of the excavation cycle, the day pitch pusher 33 is operated to pivot the stiff leg 13 to its upper rearmost position, the hoist frame 14 is operated upward and rearward, and the day pitch pitch control device described above is operated. The cylinder structure 151, which is a holding means, is put into a non-operating state so that the dipper 16 is positioned as indicated by the imaginary line in FIG.

To move the front end structure 10 backward, the motor 110 shown in FIG. 6 is operated to supply pressure fluid to the chambers 97, 97a and move the movable cylinders 95, 95a forward.

At the same time, assuming that the valve 140 is open and the pressure accumulator 137 is accumulating pressure, this pressure is also applied to the movable cylinder 95.
, 95a to the extended position, thus reducing the amount of energy input required to prime mover 110.

On the other hand, if the pressure accumulator 137 is not accumulating pressure,
The reduced pressure in tube 138 causes valve 146 to open and fluid to flow into fluid tube 138 .

After the front end structure is positioned as shown in phantom in FIG. 1, the excavation cycle of the excavator can be started by reversing the direction of prime mover 110 and directing pressurized fluid through main pump 108 to fluid supply line 113, 114 to the chambers 100, 100a of the working cylinder structures 90, 91.

Due to this action, the movable cylinders 95, 95a move backward, so the support link 39 and the operating link 41 cooperate to move the mast 3.
5, the stiff leg 13 is moved forward.
pivots forward and downward due to the combination of the weight of the front end structure 10 and the force produced by the pushing device 33.

At the same time, the hoist mechanism 19 is activated and the hoist line 148
When the shovel 16 is pivoted forward while operating the hoist frame 14 so as to move away from the stiff leg 13, the shovel type action characteristic of the above-mentioned type of excavator is performed.

As the sliding action progresses, the date pad 16 pivots so that its bottom wall is positioned horizontally on the ground.

Next, the operator operates a predetermined control device to lock the piston of the cylinder structure 151, and as the sliding action of the front end structure continues, the pitch of the dipper is kept constant by the dipper pitch control device. It is pushed into the material being excavated along the transition line to the maximum advance position.

During the pushing action of the dayper, the fluid flows into the working cylinder 9.
It is pushed out from the chambers 102, 102a of 0 and 91a and loads the pressure accumulator 137.

At the end of the pushing operation of the excavation cycle, where the dipper 16 makes maximum penetration into the material being excavated, the operator operates a predetermined control device to reverse the direction of the prime mover 110 and transfer pressurized fluid to the fluid supply line 111. , 112 to the chambers 97, 97a of the actuating cylinder structures 90, 91, moving the movable cylinders 95, 95a forward and retracting the actuating link 41 and the movable mast 35.
retreats.

At the same time, when the operator operates a predetermined control device to release the piston of the cylinder structure 151, the dipper 16 is pitched upward until the butt 32 of the dipper engages the lower end of the pitch stopper 31.

When such action occurs, the hoist line 148 is engaged and hoists the dumpster until it reaches its contents dumping position.

The rotation mechanism of the dipper is then operated to position the dipper above the material dumping area, and the door can be unlocked to release the material.

Thereafter, the hoist mechanism 19 is operated to unwind the hoist line 148, and the shovel propulsion and rotation equipment is operated to return the front end structure 10 to the starting position for the next excavation cycle.

At the same time, during the retreat of the front end structure and the body, the pressure of the pressure accumulator 137 causes the chambers 102, 102a of the cylinder structures 90, 91 to
The pressure generated can assist in retraction of the front end structure.

When the movable cylinders 95, 95a are advanced, the second
In the figure, support link 39 is pivoted to a rearward position shown in dotted lines.

Such movement is transmitted through the push actuation link 41 to the movable mast 35, which is pivoted to a rearward position shown in phantom.

The rearward pivoting of the mast is transmitted to the hoist frame 14 via the connecting link 37, which causes the stiffener leg 13 to pivot rearwardly, thus retracting the entire forward end structure.

Conversely, when the movable cylinders 95, 95a are retracted, the components of the dipper pushing device 33 return to the solid line position in FIG. 2, providing a force combined with the force of the weight of the front end structure 10 to force the dipper into the excavated material .

As shown in FIGS. 1 and 2, the components of the pushing device 33 are located at the rotation center line C of the main frame 12 as shown in FIG. L
The pushing device is mounted at the front and rear of the main frame to evenly distribute the weight load of the pushing device onto the main frame.

Further, since the brackets 107, 107a supporting the lower ends of the actuating cylinder structures 90, 91 are located above or adjacent thereto to the extent that the arrangement of the components in the deck 48 of the main frame allows, the actuating cylinders Forces occurring along the axis of the structure are applied on or adjacent to the roller circle to minimize bending moments in the main frame.

In the embodiment, the actuating cylinder structures 90 and 91 with three chambers are used to advance and retract the front end structure.
and is used to load energy storage means.

As a modification of such an arrangement, two or more conventional actuating cylinder structures each having two chambers may be utilized, one chamber of which is an energy storage means, i.e. a pressure accumulator. The other chamber of the structure connected to the vessel is connected to a working pump for advancing and retracting the piston.

In such configurations, conventional cylinder structures interconnect the various components of the shovel that move relative to each other, and various combinations of three-chamber and two-chamber cylinder structures are used to interconnect the various components of the shovel that move relative to each other. connect each other.

As a modification of the variable displacement pump described in connection with the previous embodiment, a constant displacement pump with a four-way control valve can be used.

However, the use of such constant displacement pumps reduces controllability and efficiency and eliminates the ability to regenerate and supply energy to the prime mover.

From the previously described embodiments, the energy input is reduced without reducing the work output as a result of the conservation of potential energy in the front end structure.

Such energy conservation is achieved by converting the potential energy of the front end structure into stored energy in the form of compressed gas within the gas compression type accumulator.

In the embodiment described above, the actuating cylinder structure 9 of the pushing device 33
Reference numeral 0,91 has a structure that functions to load the energy storage means during the push-in operation of the date pad, and acts as a hydropneumatic spring to displace the front end structure 10 to the raised or retreated position as an energy regeneration source. As disclosed, the present invention collects and stores potential energy in one or a combination of components of a leading edge structure and utilizes such energy to automatically or selectively select one or more components of a leading edge structure. It is also intended to make the user perform a predetermined exercise.

Various possible configurations for recovering and utilizing the potential energy of the leading end structure include connecting the main frame to the leading end component, or connecting various components of the leading end structure to direct the predetermined movement of the component. Various combinations of actuating cylinders for performing a given movement, from the potential energy of the front end structure that can automatically or selectively generate a force that acts on one or more of the components of the front end structure to perform a predetermined movement. There is a pressure accumulator that stores the converted energy, and an actuating cylinder structure that is actuated by a predetermined movement of a component of the front end structure to convert its potential energy into stored energy of the pressure accumulator.

For example, the potential energy of the leading end structure in the raised or retracted position can be converted and stored during the push-in period of the excavation cycle and then applied to the day spa pitch control device to assist in lifting the day spa.

From the foregoing detailed description, it will be apparent to those skilled in the art that various changes and modifications may be made to the present invention.

All such modifications that do not depart from the spirit of the invention are intended to be within the scope of the invention.

Embodiments of the invention are as follows.

1) Stiff leg 1 pivotally installed at the front of the main frame 12
3. a day spa arm 15 pivotally supported on the stiff leg 13; a day spa 16 supported by the day spa arm 15; a hoist link 17 connecting the front end of the hoist frame 14 pivotally mounted on the stiff leg 13 and the upper end of the day spa 16; a hoist mechanism 19 installed at the rear end of the hoist frame 14; a movable mast 35 whose lower end is pivotally supported by the main frame 12; a connection link 37 connecting the upper end of the movable mast to a part of the hoist frame 14; An operating cylinder structure 90 whose lower end is pivoted to the main frame 12 and oriented rearward from the mast; an operating link 41 connecting the operating end of the operating cylinder structure 90 to the center of the movable mast 35; In a power shovel including a support link 39 whose lower end is pivotally supported to the main frame and whose upper end is connected to the operating end of the operating cylinder structure 90, a fixed piston 94 is provided inside the operating cylinder structure 90, and the fixed piston 94 A first chamber 97 is created between the fixed piston 94 and the movable cylinder 95 by mounting the movable cylinder 95 on the outside of the cylinder structure 90.
and the movable cylinder 95 between the second chamber 100 and the third chamber 10.
2 and selectively supplies pressure fluid to the first and second chambers 97, 100, and a third chamber 102.
A hydraulic closed circuit 138, 13 having a pressure accumulator 137 in a part thereof
2) The operating cylinder structure has a lower end pivotally supported on the main frame, and an operating end that is one of the pivot points between the operating link and the support link. 3) The pivot point of the movable mast to the main frame is located forward of the longitudinal vertical centerline of the main frame, and the pivot point between the support link and the main frame is 4) The device according to item 1 above, which is arranged behind the vertical center line, and the actuating link, the actuating cylinder structure and the support link are arranged in the longitudinal direction of the main frame.4) Energy storage in the actuating hydraulic circuit of the actuating cylinder structure. and means for charging the energy storage means responsive to a rapid depressurization of the fluid in the working cylinder structure. The hydraulic circuit for supply is a two-way variable displacement pump,
and the device according to item 4 above, comprising a fluid supply pipe that connects this pump and both ends of the cylinder to form a closed fluid circuit. 6) Pressure relief valve or the like that limits the fluid pressure in the fluid supply pipe to a predetermined pressure. 7) A device according to paragraph 5 above, comprising restriction means; 7) an input side communicating with a fluid reservoir as a means for replenishing fluid in the fluid supply tube and one or both of the fluid tubes responsive to a predetermined pressure in the fluid supply tube; 8) The replenishment means includes a pressure accumulator in communication with the output side of the auxiliary pump and in communication with a fluid supply line responsive to said predetermined pressure. 9) A valve that opens in response to a predetermined pressure in the fluid supply pipe as a means for removing fluid from the fluid supply pipe and selectively communicates the fluid supply pipe with the fluid reservoir at the predetermined pressure. 10) The apparatus of claim 4, including means for selectively communicating the energy storage means to opposite ends of the actuating cylinder structure in response to a predetermined condition. 11) The actuating cylinder structure comprises: A cylinder and a fixed piston are installed in the cylinder, a movable cylinder is installed on the fixed piston in the cylinder, a first variable volume chamber is formed by the fixed piston and the movable cylinder, and the movable cylinder and the cylinder a second variable volume chamber is formed by the movable cylinder, the fixed piston and the cylinder, and means for selectively supplying pressurized fluid to both ends of the cylinder comprises the first and the third variable volume chambers. a second variable volume chamber, the charging means including a hydraulic closed circuit connecting the movable cylinder connected to the date pusher actuating component, and the third chamber and the energy storage means; 12) The apparatus of claim 11, wherein the hydraulically closed circuit includes a shutoff valve. 13) Hydraulic closure between the shutoff valve and the third variable volume chamber when the shutoff valve is closed. means for limiting the pressure in the circuit to a predetermined pressure; and means for limiting the pressure in the hydraulic closed circuit between the energy storage means and the isolation valve to a predetermined pressure when the isolation valve is closed. 14) The device according to clause 12), wherein the means responsive to a rapid depressurization of the fluid within the working cylinder structure is in communication with a fluid chamber of the working cylinder structure and is capable of responding to a pressure greater than a predetermined pressure of the fluid within said fluid chamber. 13. The apparatus of claim 12, including a relief valve that opens in response, and a fluid line interconnecting the relief valve and the pressure accumulator, the fluid line including a check valve.

[Brief explanation of the drawing]

FIG. 1 is a side view of a power shovel embodying the present invention;
FIG. 2 is an enlarged side view of a part of the pushing device of the embodiment shown in FIG. 1, FIG. 3 is a view taken in the direction of line ■-■ in FIG.
Figure 4 is a view taken in the direction of the IV-IV line in Figure 2, Figure 5 is a cross-sectional view taken along the ■-■ line in Figure 2, and Figure 6 is the indentation used in the example. 1 is a schematic diagram of a fluid-operated device including a portion of the device; 10... Front end structure 12... Main frame, 13.
... Stiff leg, 14 ... Hoist frame, 15
... Daytsupa arm, 16... Daytsupa, 17...
・Hoist link, 33... Date pad pushing device, 1
9... Hoist mechanism, 35... Movable mast, 24.
...Head axis, 37... Connection link, 41... Operating link, 39... Support link, 90, 91... Operating cylinder structure, 92... Fluid supply circuit, 94, 9
4a... solid piston, 95, 95a... movable cylinder, 96, 96a... operating end (connection bracket),
108... Main pump, 110... Prime mover, 137...
...Pressure accumulator, 140...Shutoff valve.

Claims (1)

[Claims] 1 A stiff leg pivotally mounted on the front part of the main frame, a day spa arm pivoted on the stiff leg, a day spa supported by the day spa arm, and a front end of a voice frame pivotally mounted on the stiff leg and an upper end of the day spa are connected. a hoist link installed at the rear end of the hoist frame, a movable mast whose lower end is pivotally supported by the main frame, a connecting link connecting the upper end of the movable mast to a part of the hoist frame, and the main frame. an actuating cylinder structure having a lower end pivoted to the mast and oriented rearward from the mast; an actuating link connecting the actuating end of the actuating cylinder structure to the center of the movable mast; In a power shovel including a support link whose upper end is connected to the working end of the working cylinder structure, a fixed piston is provided inside the working cylinder structure, and a movable cylinder is mounted outside the fixed piston to fix the working cylinder. A first chamber is formed between the piston and the movable cylinder, and second and third chambers are formed between the cylinder structure and the movable cylinder, and pressurized fluid is selectively supplied to the first and second chambers. An operating device for a power shovel, characterized in that a hydraulic circuit is connected to a third chamber, and a hydraulic closed circuit having a pressure accumulator is connected to a third chamber.