초록 ▼

A hydraulic pressing and/or cutting tool (1) comprises an electric motor (6), a converting mechanism (8) suitable to convert the rotary motion of the motor (9) to an oscillating translational motion, a hydraulic pump (11) suitable to carry out, in response to the oscillating translational motion, an

A hydraulic pressing and/or cutting tool (1) comprises an electric motor (6), a converting mechanism (8) suitable to convert the rotary motion of the motor (9) to an oscillating translational motion, a hydraulic pump (11) suitable to carry out, in response to the oscillating translational motion, an increase in the pressure of a pressure fluid acting on an operating piston (12) such that the operating piston (12) is displaced, a stationary jaw (13) and a movable jaw (14) connected to the operating piston (12) such that, in response to the displacement of the operating piston (12), the movable jaw is displaced to the stationary jaw (13) to carry out pressing or cutting operations. The converting mechanism (8) comprises an epicycloidal gear (16) and a thrust unit (17) co-axial with the epicycloidal gear (16).

대표청구항 ▼

1. A hydraulic pressing and/or cutting tool (1) comprising: an electric motor (6) powered by an accumulator (5) and comprising a drive shaft (9);a converting mechanism (8) connected to the drive shaft (9) and suitable to convert the rotary motion of the drive shaft (9) to an oscillating translationa

1. A hydraulic pressing and/or cutting tool (1) comprising: an electric motor (6) powered by an accumulator (5) and comprising a drive shaft (9);a converting mechanism (8) connected to the drive shaft (9) and suitable to convert the rotary motion of the drive shaft (9) to an oscillating translational motion; a hydraulic pump (11) connected to the converting mechanism (8) and suitable to carry out, in response to the oscillating translational motion, an increase in the pressure of a hydraulic fluid acting on a drive piston (12) such as to displace the drive piston (12);two jaws (13, 14) connected to the housing (2) in a movable manner relative to each other, of which at least one movable jaw (14) is connected to the drive piston (12) such that, in response to the displacement of the drive piston (12), the jaws (13, 14) carry out a relative movement for performing compression or cutting,characterized in that the converting mechanism (8) comprises: a epicycloidal gear (16) connected to the drive shaft (9) and suitable for reducing the rotary motion of the drive shaft (9);a thrust unit (17) comprising a rotating plate (18), a displaceable but rotatably-locked translatable plate (10) and cam-thrust members (19) arranged between the two facing plates and in rolling contact with rolling tracks (20, 21) thereof, wherein at least one of the rolling tracks (20) is cam-shaped such that the rotation of the rotating plate (18) causes a translational oscillating motion of the translatable plate (10),wherein the thrust unit (17) is co-axial with the epicycloidal gear (16) and the rotating plate (18) is connected by means of pins (25) to a train of planets (22) of the epicycloidal gear (16) such as to rotate in response to the revolution motion of the train of planets (22). 2. The tool (1) according to claim 1, wherein the epicycloidal gear (16) comprises a central pinion (23), a stationary-ring (24) with inner teeth, and a set of planetary gear wheels (22) that gear both with the central pinion (23) and the stationary ring (24), wherein the central pinion (23) is co-axial with the drive shaft (9) and rotatably integrally coupled thereto, and each planetary gear wheel (22) is connected to the rotating plate (18) by means of a corresponding dragging pin (25). 3. The tool (1) according to claim 1, wherein the epicycloidal gear (16) comprises three planetary gear wheels (22) arranged at a constant 120° angular pitch. 4. The tool (1) according to claim 1, further comprising an axial bearing (26) in contact with the rotating plate (18) and between the epicycloidal gear (16) and the thrust unit (17). 5. The tool (1) according to claim 1, wherein said cam rolling track (20) is formed in the rotating plate (18), and the rolling track (21) of the translatable plate (10) is substantially planar in the rolling direction. 6. The tool (1) according to claim 1, wherein said cam rolling track (20) has an asymmetric undulated profile with two diametrally opposite peaks (30) and two diametrally opposite valleys (31), wherein the angle of ascent (S) from a valley (31) to the adjacent peak (30) is lower than the angle of descent (ΩD) from a peak (30) to the adjacent valley (31) in the rolling direction of the cam-thrust member (19). 7. The tool (1) according to claim 1, wherein a bending radius (RP) of the rolling tracks (20, 21) in a cross-section transverse to the rolling direction is lower than a bending radius (RS) in a cross-section transverse to the rolling direction of the cam-thrust members (19). 8. The tool (1) according to claim 1, wherein the cam-thrust members (19) consist of a set of two balls (19) arranged diametrally opposite with reference to the axis of rotation (X) of the rotating plate (18). 9. The tool (1) according to claim 1, comprising a positioner (32) which at least partially envelops both balls and holds said balls in said diametrally opposite position, said positioner (32) pivotally supported by a pin (33) co-axially connected to the translatable plate (10) and spaced apart from both plates (10, 18) by means of shimming members (34). 10. The tool (1) according to claim 1, wherein the translatable plate (10) is supported in a guided manner along three guide axes (35) circumferentially arranged about the axis of rotation (X) of the rotating plate (18) at a constant 120° angular pitch. 11. The tool (1) according to claim 1, wherein said hydraulic pump (11) comprises: said operating piston (12) accommodated within an operating cylinder (43);a pumping cylinder (39) having an intake port (40) and a drain port (42) being in non-return communication with the operating cylinder (43);a pump piston (45) accommodated within the pumping cylinder (39) and translationally coupled with the translatable plate (10);a pressure fluid reservoir (37) in non-return communication with the intake port (40) of the pumping cylinder (39);a pressure relief valve (38) arranged in a return duct (47) of the fluid, connecting the operating cylinder (43) to the reservoir (37) to allow the operating piston (12) to return to an opened position of the jaws (13, 14). 12. The tool (1) according to claim 1, wherein said pressure relief valve (38) comprises: a plug (48) biased by a return spring (49) to a closed position in which said plug closes a passage opening in the fluid return duct (47),said plug (48) configured such that the pressure fluid, after a preset maximum pressure has been reached, pushes the plug (48) temporarily to an open position, thus clearing the passage opening; a valve-locking spring (50) suitable to snap-engage an edge (51) of the plug (48) when the latter reaches the open position and retain the plug (48) in said open position to allow the backflow of the pressure fluid in the reservoir;a release spring (52) interacting with an operating pushbutton (7) of the tool, such that, in response to an operating movement by the push-button (7), the release spring (52) disengages the valve-locking spring (50) from the plug (48) to allow the plug (48) to return to the closed position, wherein said push-button (7) interacts with an electric switch in the motor supply circuit such as to cause the operation of the motor with the pressure relief valve being closed. 13. A motion converting mechanism (8) for a hydraulic pressing and/or cutting tool (1) of the type comprising: an electric motor (6) powered by an accumulator (5) and comprising a drive shaft (9);a converting mechanism (8) connected to the drive shaft (9) and suitable to convert the rotary motion of the drive shaft (9) to an oscillating translational motion; a hydraulic pump (11) connected to the converting mechanism (8) and suitable to carry out, in response to the oscillating translational motion, an increase in the pressure of a pressure fluid acting on a drive piston (12) such as to displace the drive piston (12);two jaws (13, 14) connected to the housing (2) in a movable manner relative to each other, of which at least one movable jaw (14) is connected to the drive piston (12) such that, in response to the displacement of the drive piston (12), the jaws (13, 14) carry out a relative movement for performing compression or cutting,characterized in that the motion converting mechanism (8) comprises:an epicycloidal gear (16) connected to the drive shaft (9) and suitable for reducing the rotary motion of the drive shaft (9);a thrust unit (17) comprising a rotating plate (18), a displaceable but rotatably-locked plate (10), and cam-thrust members (19) arranged between the two facing plates and in rolling contact with rolling tracks (20, 21) thereof, wherein at least one of the rolling tracks (20) is cam-shaped such that the rotation of the rotating plate (18) causes a translational oscillating motion of the translatable plate (10), wherein the thrust unit (17) is co-axial with the epicycloidal gear (16) and the rotating plate (18) is connected by means of pins (25) to a train of planets (22) of the epicycloidal gear (16) such as to rotate in response to the revolution motion of the train of planets (22).