JPH07241720A - Hydraulic actuation mechanism of portable shearing machine - Google Patents

Abstract

PURPOSE:To provide a hydraulic actuation mechanism which can attain miniaturization and weight reduction of a portable shearing machine and the portable shearing machine. CONSTITUTION:A crankshaft 35 integratedly connected to the front edge of a rotary drive shaft 34 is provided. The crankshaft 35 is provided with two eccentric cam parts 35A, 35B in line, respective eccentric quantities are equal to each other, and they are positioned at angular intervals of 180 degrees. Needle bearings 38 arranged on the outer circumference of the respective cam parts are brought in slidable contact with respective plungers 101 of pump units 100A, 100B, and the respective plungers are alternately elevatably moved at correct phase interval of 180 degrees. Hence, in the pump part, at every half rotation of the rotary drive shaft 34, the first pump unit and the second pump unit continue suction of hydraulic oil in a oil reservoir and force feed of the oil to the oil pressure chamber 52 of a cylinder device 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic actuating mechanism for a portable shearing machine, and more particularly, to a fluid actuating cylinder portion having a piston rod for reciprocating a movable tool such as a movable blade or a punch. And a hydraulic pump unit for supplying a working fluid to the cylinder unit, a rotary drive shaft for driving the pump unit, and a drive unit for rotating the rotary drive shaft. It is related to the mechanism.

[0002]

2. Description of the Related Art A portable shearing machine for cutting or punching steel materials is used for steel material working operations in the fields of construction work, construction equipment work, machine making or machining. This type of shearing machine is generally configured to shear a steel bar such as a reinforcing bar or a full-screw bolt mainly with a pair of fixed blades and movable blades, or to punch a plate material such as a steel plate mainly with a die and a punch. It is provided with various parts structure according to the purpose of use, and is commercially available under the device name such as a reinforcing bar cutter, a full-screw cutter or a puncher according to each application (for example, Japanese Patent Application No. 1-93035 and Japanese Patent Application Laid-Open No. 3935/1993) -189022
Japanese Patent Application, Japanese Patent Application No. 4-80839, Japanese Patent Application No. 4-4718
No. 1, Japanese Patent Application No. 4-80839, etc.). Generally, a shearing machine of this type includes a fixed tool such as a die or a fixed blade integrally supported by a casing of a main body, a hydraulic operation mechanism including a piston rod, a punch attached to a tip portion of the piston rod, A movable tool such as a movable blade is provided, and a steel material interposed between a fixed tool and a movable tool is punched or cut by extension of a piston rod. The hydraulic operating mechanism of such a shearing machine includes a fluid-operated cylinder device that reciprocates a piston rod, and a pump unit that constitutes an operating hydraulic pressure source of the cylinder device. The pump unit configures a drive unit of the shearing machine. And is operated by the single-phase AC motor or DC rechargeable motor. Also,
This type of shearing machine generally comprises a main handle or a portable handle that can be gripped by the operator's fingers. The operator grips the portable handle or the like to carry or carry in the shears, and during the cutting or punching work, grasp the portable handle with one hand and the auxiliary handle or the main body part with the other hand. And hold the shear firmly in place.

[0003]

As is apparent from the above working mode, in the shearing machine of the above type, the overall size and weight of the device are reduced, and the portability of the device and the workability or operability of the shearing work are improved. Improving is a very important design and manufacturing condition. However, the pump unit in the conventional shearing machine incorporates a plurality of (for example, four sets) pump units radially extending around the motor shaft in order to ensure a desired pump efficiency. Therefore, the outer diameter of the pump cannot be reduced as desired. Further, the lightest shearing machine currently on the market, for example, a reinforcing bar cutter is a reinforcing bar cutter of the model number IS-13MC manufactured by the applicant of the present application. This product has an overall weight of only about 4.7 kg due to the thinning of the shear jaws or jaws. This shearing machine achieves the intended purpose of reducing the weight of the shearing machine by improving the structural members,
In order to further improve the portability or workability of the shears, it is desirable to achieve further weight saving of the shears from different viewpoints. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydraulic operating mechanism capable of achieving downsizing and weight saving of a portable shearing machine, and a portable shearing machine including the hydraulic operating mechanism. To provide.

[0004]

In order to achieve the above object, the present invention provides a fluid actuated cylinder portion having a piston rod for reciprocating a movable tool, and a working fluid to the cylinder portion. In a hydraulic operating mechanism of a portable shearing machine comprising a fluid pressure pump unit for supplying, a rotary drive shaft for driving the pump unit, and a drive unit for rotating the rotary drive shaft, the pump unit includes the rotary drive shaft. A crankshaft connected to the shaft, and a pair of pump units operated by rotation of the crankshaft, wherein the crankshaft has a pair of eccentric cam portions connected in series in the axial direction of the rotary drive shaft. Each of the pump units includes a pair of reciprocating plungers facing the eccentric cam portion, and a biasing means for biasing the plunger toward the cam portion. And is arranged to reciprocate in synchronism with the rotation of the eccentric cam part to repeat the discharge process and the suction process, and the eccentric cam part is configured to discharge the first pump unit and suction the second pump unit. And occur substantially at the same time, and the suction step of the first pump unit,
A hydraulic operating mechanism for a portable shears, wherein the second pump unit is arranged at a predetermined angular position around the crankshaft so that the discharging step and the discharging step of the second pump unit occur substantially at the same time.

According to the above configuration of the present invention, when the plunger of the first pump unit is moved forward by the rotation of the rotary drive shaft to execute the discharging process, the plunger of the second pump unit is moved back and sucked. When the process is executed and the plunger of the second pump unit moves forward to execute the discharge process, the plunger of the first pump unit moves back to execute the suction process. Therefore, while the rotary drive shaft makes one revolution, each pump unit executes the discharge process and the suction process, respectively, and pumps the hydraulic oil to the cylinder portion. Moreover, the discharge process of the one pump unit and the discharge process of the other pump unit do not substantially overlap with each other, and the pump unit pumps the hydraulic oil to the cylinder unit with high pump efficiency. According to the shearing machine configured in this way, the capacity of the electric motor that constitutes the drive unit can be reduced, and the motor body can be made smaller and lighter. Further, in the shearing machine provided with the charging battery, the capacity of the charging battery can be reduced, and the charging battery can be made small and lightweight. In a preferred aspect of the present invention, the raised portions of the eccentric cam portion are arranged at positions separated by 180 degrees around the rotation center axis of the rotary drive shaft. As a result, the discharge process of one pump unit and the suction process of the other pump unit can be completely synchronized or matched, and the pump efficiency can be maximized.

In one preferred embodiment of the invention,
A needle bearing is arranged on the outer periphery of the eccentric cam portion, and the pump units are arranged in parallel below the crankshaft. Preferably, the stroke of the reciprocating motion of the plunger is set such that the tip end surface of the plunger is located above the discharge-side oil passage at the end of the discharge process,
The full reciprocating stroke of the plunger effectively acts on discharge and suction. More preferably, a plunger slide passage extending in a direction orthogonal to the rotation center axis is bored in the pump housing, and a return spring biasing the plunger toward the eccentric cam portion is arranged in the slide passage. A suction valve is inserted between the slide passage and the oil storage chamber, and a discharge-side oil passage is connected to a side wall of the slide passage to prevent a backflow of pressure oil to the discharge-side oil passage. A valve is arranged in the discharge side oil passage. In a preferred embodiment of the present invention, an automatic release valve device is provided for releasing the pressure oil in the high pressure side hydraulic chamber of the cylinder portion when the piston of the cylinder portion advances to a predetermined position. As a result, the cylinder portion can automatically retract the piston.
Preferably, a collecting oil passage that is connected to the discharge-side oil passage of each pump unit and joins the discharged working oil, and a pressure regulating valve that communicates with the discharge-side oil passage or the collecting oil passage are provided.

The present invention also provides a portable shear having the hydraulically actuated mechanism. The shearing machine having such a structure has an electric motor of a driving unit which is smaller and lighter than a conventional shearing machine, and in the case of a shearing machine with a built-in charging battery,
It has a relatively small and lightweight rechargeable battery. In a preferred embodiment of the present invention, the shearing machine has an electric motor that rotates the rotary drive shaft, and a casing that houses the electric motor, and the casing has a larger capacity than the electric motor. And a spacer that is arranged in a surplus space when the electric motor having a relatively small capacity is stored in the motor storage area. As a result, the electric motor can be replaced with a large-sized one, so that compatibility or versatility of the shears can be improved, or the casings constituting the shears can be shared. In another preferred embodiment of the present invention, the shearing machine has a DC power supply type electric motor that rotates the rotary drive shaft, and a battery case that stores a power supply battery for the electric motor.
The battery case has a battery storage area capable of storing a large-sized power supply battery having a larger capacity than the power supply battery. As a result, the rechargeable battery can be replaced with a large one, so that the compatibility or versatility of the shears can be improved, or the casings constituting the shears can be shared.

In still another preferred embodiment of the present invention, a linear member extending in the circumferential direction is interposed between the cylinder case of the cylinder portion and the cylinder connecting portion through which the piston rod passes. Circumferential grooves at least partially accommodating the linear member are respectively formed on the opposing surfaces of the cylinder case and the cylinder connecting portion, and the cylinder case and the cylinder connecting portion make frictional contact with each other via the linear member. . According to this structure, the head portion of the shears can be displaced to an arbitrary rotation angle position.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A shearing machine according to a preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. 1 and 2 are a side view and a plan view of a portable rebar cutter according to an embodiment of the present invention. 1 and 2, a portable rebar cutter 1 (hereinafter, referred to as a cutter 1) includes a drive unit 3 having a portable handle 2, a pump unit 4 connected to the drive unit 3, and a hydraulic pressure together with the pump unit 4. The hydraulic cylinder portion 5 that constitutes the operating mechanism and the jaw-shaped head portion 6 that extends forward from the hydraulic cylinder portion 5 are substantially configured. The portable handle 2 is formed integrally with the casing of the drive unit 3 and extends downward from the casing, and is designed to have a size and shape that allows an operator to hold it with one hand, for example, a finger of the right hand. ing. A trigger switch 7 for manually controlling the operation of the drive unit 3 is arranged on the front side surface of the portable handle 2, and a battery case 20 capable of accommodating a rechargeable battery is arranged at the lower end of the handle 2. There is. The drive unit 3 has a built-in DC rechargeable motor (not shown), and the motor is connected to a power source in the battery case, that is, a charging battery (not shown). The drive unit 3 further includes an output shaft (not shown) extending into the pump unit 4. The output shaft of the drive unit 3 drives a hydraulic pump unit (not shown) provided in the pump unit 4, and the pump unit 4 supplies pressure oil to the hydraulic cylinder unit 5.

The hydraulic cylinder portion 5 is provided with a piston / cylinder mechanism (not shown), and is configured to extend the piston rod 8 fixed to the piston with pressure oil. The movable blade 9 is detachably fixed to the tip of the piston rod 8, and the fixed blade 10 is arranged at a position facing the movable blade 9 in the axial direction of the piston rod 8. The fixed blade 10 is detachably attached to the front end portion of the jaw-shaped head portion 6 at a position laterally displaced from the movable blade 9. When the movable blade 9 moves forward due to the extension of the piston rod 8, the movable blade 9 and the fixed blade 10 shear the reinforcing bar W (shown by an imaginary line) interposed between the movable blade 9 and the fixed blade 10, that is, in the shearing direction. , Cut in the direction perpendicular to the axis of the rebar. 3 and 4 are enlarged vertical sectional views of the reinforcing bar cutter shown in FIG. The battery case 20 located at the lower end of the portable handle 2 is configured to accommodate a rechargeable battery of 12V to 14V or less. Rebar cutter 1 of this example
Then, the 9.6V rechargeable battery is the battery case 2
It is housed in 0. In the casing of the drive unit 3,
An electric motor main body 30 connected to a charging battery in a battery case 20 is arranged, and the motor main body 30 is composed of a DC power supply type electric motor, which is smaller than an electric motor conventionally used in a rebar cutter of this type, or It is a low capacity electric motor. An inner wall surface 3 a that is complementary to the contour of the rear end surface of the motor body 30 is formed on the rear end wall of the casing of the drive unit 3. The inner wall surface 3a is spaced from the rear end surface of the motor main body 30, and a light-weight member such as a resin molded product, a foam molded product or a hollow molded product is provided between the wall surface 3a and the motor main body rear end surface. The spacer 3b is inserted. When changing the motor capacity, the spacer 3b is removed and a large capacity electric motor is replaced with the motor body 30.

The output shaft 31 of the motor body 30 has the shearing machine 1
The shaft 31 extends forward on the central axis line XX, and the output shaft 31 is press-fitted into the pinion 32. A sun gear 33 a of the planetary gear mechanism 33 is integrally formed with the pinion 32. The planetary gear mechanism 33 includes an idle gear 33c and a planetary carrier 33 connected to a rotary drive shaft 34.
b, the torque of the output shaft 31 is output to the rotary drive shaft 34 via the planetary gear mechanism 33. The pinion 32 and the rotary drive shaft 34 are rotatably supported by bearings 36, 36. The oil seal 39, which is in sliding contact with the outer peripheral surface of the rotary drive shaft 34, liquid-tightly isolates the drive unit 4 and the pump unit 4. The crankshaft 35 arranged in the pump portion 4 is integrally connected to the front end of the rotary drive shaft 34. The front end of the crankshaft 35 is
It is rotatably supported by the bearing 37. The crankshaft 35 includes two eccentric cam portions 35A connected in series,
35B, and the cam portions 35A and 35B have the rotary drive shaft 3
The eccentric amount of each of the cam portions 35A and 35B is equal to each other with respect to the rotation center axis line of 4 (center axis line XX). Further, the eccentric directions of the cam portions 35A and 35B are set to be diametrically opposite to each other.
The angular positions of the raised portions or the raised surfaces of 5A and 35B are set at positions spaced by 180 degrees from each other around the rotation center axis. On the outer circumference of each cam portion 35A, 35B,
A needle bearing 38 having a roller and a roller follower is arranged concentrically with each cam portion 35A, 35B,
The needle bearing 38 is rotatably supported by the cam portions 35A and 35B.

In the housing 40 of the pump portion 4, an oil tank 42 for containing hydraulic oil is formed. A supply port 48 is formed above the oil tank 42 so as to penetrate the housing 40 through the wall body, and a plug 49 is screwed into the supply port 48. The pump unit 4 includes a pair of pump units 100A and 100B.
Equipped with. The pump units 100A and 100B are respectively
A plunger piston or a reciprocating plunger 101 (hereinafter referred to as the plunger 101) and a return spring 102 are provided. A plunger slide path 103 extending in a direction orthogonal to the rotation center axis line XX is bored in the lower wall portion of the housing 40.
The return spring 10 is arranged so that it can move up and down in 3
2 is arranged in the sliding path 103 so as to bias the plunger 101 upward. Thus, the plunger 101
Reciprocates (moves up and down) with the upper end surface always in sliding contact with the needle bearing 38. A suction valve 104 is attached to the lower end of the sliding path 103. The intake valve 104 communicates with an oil storage chamber 43 that is connected to the lower portion of the housing 40. The oil storage chamber 43 includes pump units 100A, 100
A flexible film 44, which is generally called an oil pack, is for accumulating the hydraulic oil to be sucked by B and compensating for the volume change of each hydraulic chamber of the hydraulic cylinder portion 5.
It is defined by. A casing 45, generally called an oil pack case, is arranged outside the flexible film 44, and the casing 45 is fixed to the lower end portion of the housing 40. An air chamber 46 is formed between the flexible film 44 and the casing 45, and the air chamber 46 includes the casing 45.
Is opened to the atmosphere by an air hole 47 formed in the lower end wall of the.

The suction valve 104 is a check valve provided with a ball 105 and a compression spring 106 which are arranged so as to pass the fluid in the direction of the arrow a and prevent the fluid flow in the opposite direction. While allowing the hydraulic oil to be sucked, the reverse flow of the hydraulic oil to the oil storage chamber 43 is prevented. Slideway 1
The side wall of 03 is connected to the pressure feeding path 107, and the pressure feeding path 10
3 is connected to a connecting oil passage 111 via a direction control valve or a check valve composed of a ball 108 and a compression spring 109, and the oil passage 111 is a manifold or a collecting oil passage 1
It communicates with 10. The ball 108 and the compression spring 109 configure a check valve that allows the hydraulic oil to pass in the hydraulic oil supply direction indicated by the arrow, while preventing the hydraulic oil from passing in the reverse direction. Thus, each pump unit 100A, 100
The hydraulic fluid that has been pumped by B and passed through the check valve (ball 108 and compression spring 109) merges in the collecting oil passage 110. The collecting oil passage 110 communicates with the hydraulic chamber 52 of the hydraulic cylinder portion 5 via a hydraulic oil supply passage 113 extending upward. The collecting oil passage 110 is also connected to the pressure regulating valve 120 via a pressure regulating passage 112 extending downward. The pressure regulating valve 120 is a pressure regulating valve or a safety valve provided with a ball 121 and a compression spring 122 which are arranged so as to pass the fluid in the direction of the arrow b and prevent the fluid flow in the opposite direction, and are arranged around the collecting oil passage 110. When the pressures in the oil passage and the hydraulic chamber 52 exceed a predetermined pressure, the high-pressure hydraulic oil is discharged or discharged into the oil storage chamber 43.

FIG. 5 is a cross-sectional view of the pump portion 4 taken along the line AA of FIG. 4, and similarly, FIGS. 6 and 7 respectively show FIG.
4 is a cross-sectional view of the pump unit 4 taken along line BB and line CC of FIG. 8 is a vertical cross-sectional view of the pump housing 40 taken along the line D-D in FIG. As shown in FIG. 5, the floating balls 131 are arranged in the collecting oil passage 110,
The floating ball 131 is pressed against the reduced diameter portion 135 of the collecting oil passage 110 by the compression spring 136, and normally closes the opening (return passage) of the reduced diameter portion 135. The floating ball 131 abuts on the protrusion 133 of the actuating member 132 which penetrates the reduced diameter portion 135. The operating member 132 projects outward from the housing 40, and one end portion of a manual operation lever 139 pivotally supported by a pin 138 is provided at the operating member 13.
Abutting the outer end surface of 2. Thus, the actuating member 132
By rotating the operation lever 139 shown by the arrow, the collecting oil passage 1
Displacement in the axial direction of 10 causes the protrusion 133 to separate the floating ball 131 from the reduced diameter portion 135 against the elastic force of the compression spring 136. One end of the return oil passage 130 shown in FIG. 6 is open to the perforation 137 that accommodates the operating member 132, and the other end of the return oil passage 130 is open to the oil storage chamber 43. Therefore, when the floating ball 130 is separated from the reduced diameter portion 135 by the rotation of the operation lever 139, the hydraulic chamber 5
2 and the oil storage chamber 43, the hydraulic oil supply passage 113, the collecting oil passage 1
The pressure oil in the hydraulic chamber 52 communicates with each other via the 10, the reduced diameter portion 135, the perforation 137, and the return oil passage 130, and the pressure oil in the hydraulic chamber 52 is stored in the oil storage chamber 4
Reflux to 3.

Further, as shown in FIGS. 5 to 7, the oil tank 42
And the oil storage chamber 43 are interconnected by communication paths 140 and 141 extending in the vertical direction, and the oil tank 42 and the oil storage chamber 43 are always in communication with each other. Further, as can be easily understood from FIG. 8 showing the housing 40 with each component removed, the pumping passage 107 and the oil passage 111 which form each discharge passage of the pump units 100A and 100B are arranged in parallel. , At the collecting oil passage 110. In addition, one oil passage 11
1 is vertically aligned with the pressure regulation passage 112.
Further, FIG. 8 shows a perforation 137 that accommodates the actuating member 132 (FIG. 5) and a return oil passage 130 that allows the perforation 137 and the oil storage chamber 43 to communicate with each other, and shows the positional relationship between these components. It can be understood relatively easily from FIG. It should be noted that FIG. 8 shows perforations 124 and 125 with internal threads for attaching the pressure regulating valve 120 and the blind plug, respectively. As shown in FIG. 4, the hydraulic cylinder unit 5 includes a cylinder case 50, a piston 51 reciprocally arranged in the cylinder case 50, and hydraulic chambers 52 and 53 defined on both sides of the piston 51, respectively. I have it. The hydraulic chamber 52 communicates with the hydraulic oil supply passage 113 and can communicate with the release oil passage 54 when the release valve device 56 is opened.

The release valve device 56 includes a shaft hole 150 formed in the piston 51, a valve body 151 disposed in the shaft hole 150, a kick spring 152 engaging with a front end portion of the valve body 151, and a valve body. A perforation 15 opened at the rear end surface of the 151
1a, the float spring 153 and the valve body 15
Holding portion 154 for supporting 1 to be relatively displaceable with respect to the piston 50, and a valve seat 1 arranged on the outer periphery of the rear end of the valve body 151.
55. The holding portion 154 has a pressure introducing passage (not shown) that communicates the region inside the shaft hole 50 with the hydraulic chamber 52.
The operating hydraulic pressure of the hydraulic chamber 52 acts on the front end surface 156 of the valve body 151. Therefore, when the pressure in the hydraulic chamber 52 is increased, the valve body 151 is pressed by the cylinder rear end wall 157, the valve seat 155 continues to be seated, and the release oil passage 54 is closed. When the piston 51 moves forward by a predetermined distance, the kick spring 152 overcomes the working hydraulic pressure acting on the front end surface 156 and extends, thereby moving the valve body 151 to the cylinder rear end wall 15.
7, the float spring 153 is connected to the valve seat 1
The separated state of 55 and the cylinder rear end wall 157 is maintained.
As a result, the valve seat 155 opens the release oil passage 54 and the hydraulic chamber 52 communicates with the release oil passage 54. Thus, the hydraulic oil in the hydraulic chamber 52 is transferred to the oil tank 4 via the release oil passage 54.
2 and then to the oil storage chamber 43 via the communication passages 140 and 141.

A return spring 57 for urging the piston 51 rearward is arranged in the hydraulic chamber 53, and the return spring 57 always holds the piston 51 at the most retracted position. The piston rod 8 is integrally connected to the piston 51, and moves forward or backward as the piston 51 reciprocates. The piston rod 8 penetrates the cylinder connecting portion 60 of the jaw-shaped head portion 6 that defines the front end of the hydraulic chamber 53. In order to connect the cylinder connecting portion 60 to the cylinder case 50 so as to be rotatable relative to each other, a linear groove, for example, a circumferential groove having a substantially semicircular cross section capable of accommodating a piano wire 61 is formed on the inner peripheral surface of the cylinder connecting portion 60. They are formed on the outer peripheral surface of the cylinder case 50, respectively. The cylinder connecting portion 60 and the jaw case 6 are frictionally engaged with each other via the linear member 61, so that the cylinder connecting portion 60 and the jaw-shaped head portion 6 are rotated at arbitrary rotational positions or angular positions with respect to the cylinder case 50. It is possible to rotate relative to each other, and further, it is possible to maintain a desired rotational position or angular position. Positioning bolts for securely fixing the cylinder connecting portion 60 to the set position may be provided on the cylinder connecting portion 60 or the cylinder case 50, if desired.

Next, the operation of the rebar cutter 1 will be described. By pressing the trigger switch 7 of the portable handle 2 with a finger, power (electric power) is supplied from the charging battery in the battery case 20 to the electric motor 30, and the output shaft 31 of the electric motor 30 rotates. Output shaft 3
The torque No. 1 is transmitted to the rotary drive shaft 34 and the crankshaft 35 via the planetary gear mechanism 33. Crankshaft 35
The rotation of the eccentric cam portions 35A and 35B moves the plungers 101 of the pump units 100A and 100B up and down. The raised portions or raised surfaces of the cam portions 35A and 35B are 1
Since they are arranged at 80 degree angular intervals,
Each plunger 101 alternately moves up and down with a phase shifted by exactly 180 degrees. The hydraulic oil contained in the slide passage 103 is compressed or pressurized when the plunger 101 descends, the suction valve 104 is closed, and the ball 109 seated at the end of the oil passage 107 opens the oil passage 107. , Oil passages 107, 111
To communicate with each other. Thus, the hydraulic oil in the sliding passage 103 is not allowed to move to the oil passages 107, 11 due to the descent of the plunger 101.
1, through the collecting oil passage 110 and the hydraulic oil supply passage 113,
It is fed under pressure to the hydraulic chamber 52 of the cylinder device 5.

The pressure in the sliding path 103 is the same as that of the plunger 10.
When 1 rises, the pressure drops. Due to the pressure drop in the sliding passage 103, the ball 109 closes the oil passage 107, while the suction valve 104 opens, so that the hydraulic oil in the oil storage chamber 43 moves to the sliding passage 10
3 is sucked or inhaled. Preferably, the plunger 1
The stroke of raising and lowering or reciprocating 01 is the plunger 10
1 is set so that the lower end of the plunger 101 is located above the oil passage 107 at the maximum descent. By setting such a plunger stroke, the entire stroke of the plunger 101 can be effectively used for the discharge and suction operations. The hydraulic oil fed to the hydraulic chamber 52 of the cylinder device 5 raises the pressure of the hydraulic chamber 52 and moves the piston 51 forward against the elastic force of the return spring 57. As a result, the piston rod 8 extends, moves the movable blade 10 forward, and the movable blade 10 cooperates with the fixed blade 7 to shear the steel bar W. When the piston 51 is advanced a predetermined distance, the release valve device 56 is opened as described above, and the hydraulic chamber 52 communicates with the release oil passage 54. The hydraulic oil in the hydraulic chamber 52 is returned to the oil tank 42 via the release oil passage 54, and the hydraulic oil returned to the oil tank 42 is returned to the oil storage chamber 43 via the communication passages 140 and 141. Due to the return of hydraulic oil, the hydraulic chamber 52
Is lowered and the piston 51 is retracted to the initial position shown in FIG. 4 by the extension of the return spring 57, and thus the piston rod 8 is retracted into the cylinder device 5,
The movable blade 9 is separated from the fixed blade 10. Further, the valve body 151 of the release valve device 55 retracts as the piston 51 retracts, closing the release passage 54.

As described above, the reinforcing bar cutter 1 having the above structure
Includes a crankshaft 35 integrally connected to the front end of the rotary drive shaft 34, and the crankshaft 35 has two eccentric cam portions 35A and 35B connected in series. Cam part 35
The eccentric amounts of A and 35B are equal to each other with respect to the rotation center axis line XX of the rotary drive shaft 34, and the cam portions 35A and 35B.
The ridges or ridges of B are separated from each other about the central axis of rotation by 1
It is positioned at a position spaced by an angle of 80 degrees.
The needle bearings 38 arranged on the outer circumferences of the cam portions 35A and 35B are in sliding contact with the plungers 101 of the pump units 100A and 100B, and alternately move the plungers 101 up and down with an exact 180 degree phase difference. Therefore, the pump unit 4 is
One pump unit 100A sucks the working oil in the oil storage chamber 43, and the other pump unit 100B pumps the working oil in the slide passage 103 to the hydraulic chamber 52 of the cylinder device 5, and the rotation drive shaft 34 of During one half rotation, one pump unit 100B sucks the hydraulic oil in the oil storage chamber 43, and the other pump unit 100A pumps the hydraulic oil in the slide passage 103 to the hydraulic chamber 52 of the cylinder device 5. As described above, according to the reinforcing bar cutter 1 configured such that the suction or suction process and the discharge or push-in process do not overlap with each other and one pump unit 100A or 100B always executes the discharge process, 4 can maximize the pump efficiency, reduce the capacities of the motor body 30 and the charging battery, and reduce the size and weight of the motor body and the charging battery. For example, the lightest conventional rebar cutter has a total weight of about 4.7 kg, whereas the rebar cutter 1 only has a weight of about 3.5 kg.

Further, the eccentric cam portions 35A and 35B are connected in series in the direction of the rotation center axis line XX, and both pump units 100A and 100B are arranged below the crankshaft 35 in a substantially parallel manner. Compared with the conventional pump configuration in which a plurality of pump units are arranged radially around the central axis line XX, the diameter of the pump unit 4 can be significantly reduced, and the pump unit 4 is designed in association with the pump unit 4. The diameter of the hydraulic cylinder unit 5 can be reduced. For example,
In the conventional radial pump structure, the diameter of the hydraulic cylinder chamber in the hydraulic cylinder portion was about 65 mm, whereas in the rebar cutter 1 of this example, the diameter of the similar hydraulic cylinder chamber was reduced to about 45 mm. In addition, although the present invention is applied to the reinforcing bar cutter in the above-described embodiment, the present invention can be applied to a shearing machine such as a so-called full screw cutter or a puncher having a hydraulic actuating mechanism. Also,
The above embodiment relates to a so-called cordless type shearing machine having a rechargeable battery, but the present invention is also applicable to a shearing machine having a power cord.

[0022]

According to the present invention, it is possible to provide a hydraulic operating mechanism that can achieve the size reduction and weight reduction of a portable shearing machine, and a portable shearing machine equipped with the hydraulic operating mechanism.

[Brief description of drawings]

FIG. 1 is a side view of a portable rebar cutter according to an embodiment of the present invention.

2 is a plan view of the reinforcing bar cutter shown in FIG. 1. FIG.

FIG. 3 is an enlarged vertical sectional view showing a right half portion of the reinforcing bar cutter shown in FIG.

FIG. 4 is an enlarged vertical sectional view showing a left half portion of the reinforcing bar cutter shown in FIG.

5 is a cross-sectional view of the pump section taken along the line AA in FIG.

6 is a cross-sectional view of the pump section taken along the line BB in FIG.

7 is a cross-sectional view of the pump section taken along the line CC of FIG.

FIG. 8 is a vertical cross-sectional view of the pump housing taken along the line D-D in FIG.

[Explanation of symbols]

 1 Portable Reinforcing Bar Cutter 2 Portable Handle 3 Drive Unit 4 Pump Unit 5 Hydraulic Cylinder Unit 6 Jaw-Shaped Head Unit 7 Trigger Switch 8 Piston Rod 9 Movable Blade 10 Fixed Blade 20 Battery Case 30 Electric Motor Main Body 34 Rotation Drive Shaft 35 Crank Shaft 35A, 35B Eccentric cam part 38 Needle bearing 43 Oil storage chamber 51 Piston 52, 53 Hydraulic chamber 56 Release valve device 57 Return spring 100A, 100B Pump unit 101 Reciprocating plunger 102 Return spring 103 Plunger sliding path 104 Suction valve 108 Ball 109 Compression spring 110 Collecting oil passage 120 Pressure regulating valve W Rebar

Claims (8)

[Claims] 1. A fluid-actuated cylinder part having a piston rod for reciprocating a movable tool, a fluid pressure pump part for supplying a working fluid to the cylinder part, and a rotary drive shaft for driving the pump part. A hydraulic operating mechanism of a portable shearing machine comprising a drive unit for rotating the rotary drive shaft, wherein the pump unit is operated by a crank shaft connected to the rotary drive shaft and rotation of the crank shaft. A pair of pump units, the crankshaft includes a pair of eccentric cam portions that are connected in series in the axial direction of the rotary drive shaft, and the pump units each include a pair of reciprocating cam units that face the eccentric cam portions. A moving plunger and an urging means for urging the plunger respectively toward the cam portion, and the plunger reciprocates in synchronization with the rotation of the eccentric cam portion,
The eccentric cam portion is disposed so as to repeat the discharge step and the suction step,
The suction process of the second pump unit occurs at substantially the same time, and the suction process of the first pump unit and the discharge process of the second pump unit occur at substantially the same time. A hydraulic operating mechanism for a portable shearing machine, which is arranged at a predetermined angular position. 2. The ridges of the eccentric cam portion are arranged at positions separated by a phase of 180 degrees around the rotation center axis of the rotary drive shaft, and needle bearings are arranged on the outer periphery of the eccentric cam portion. The pump units are arranged in parallel below the crankshaft, and the stroke of the reciprocating motion of the plunger is set so that the tip end surface of the plunger is located above the discharge-side oil passage at the end of the discharge process. The hydraulic operating mechanism according to claim 1, wherein: 3. A plunger slide passage extending in a direction orthogonal to the center axis of rotation is bored in the pump housing, and a return spring for urging the plunger toward the eccentric cam portion is arranged in the slide passage. A direction in which a suction valve is inserted between the sliding passage and the oil storage chamber, the discharge-side oil passage is connected to the side wall of the sliding passage, and the backflow of pressure oil to the discharge-side oil passage is prevented. A regulating valve is arranged in the discharge side oil passage.
Alternatively, the hydraulic operating mechanism according to the item 2. 4. An automatic release valve device for releasing pressure oil in a high pressure side hydraulic chamber of the cylinder portion when the piston of the cylinder portion advances to a predetermined position. 4. The hydraulic operating mechanism according to any one of 3 above. 5. A portable shears equipped with the hydraulically actuated mechanism according to claim 1. 6. A motor storage area having an electric motor for rotating the rotary drive shaft and a casing for accommodating the electric motor, wherein the casing is capable of accommodating a large electric motor having a larger capacity than the electric motor. The portable shearing machine according to claim 5, further comprising: a spacer arranged in a surplus space when the electric motor having a relatively small capacity is housed in the motor housing area. 7. A direct current power supply type electric motor for rotating the rotary drive shaft, and a battery case accommodating a power supply battery for the electric motor, wherein the battery case has a larger capacity than the power supply battery. The portable shearing machine according to claim 5 or 6, further comprising a battery storage area capable of storing the large-sized power supply battery. 8. Between the cylinder case of the cylinder portion and the cylinder connecting portion through which the piston rod penetrates,
A linear member that extends in the circumferential direction is inserted, and circumferential grooves that at least partially accommodate the linear member are formed in opposing surfaces of the cylinder case and the cylinder connecting portion, respectively, the cylinder case and the cylinder connecting portion. And are in frictional contact through the linear member.
The shearing machine according to any one of 1 to 7.