The present invention relates to a system for cutting electric wires with a hydrodynamic cutting tool.
Hydrodynamic cutting tools are often used to perform given cutting operations, e.g. the cutting of electric wires, during electric system installation and maintenance.
Such tools comprise an electric motor and a hydraulic pump which causes an increase of a hydraulic liquid pressure operating on a piston to move the latter against the bias of a pressure spring. In turn, the piston is connected to a movable jaw so as to displace it, during the compression operation, with respect to a fixed jaw of the tool. The jaws may be shaped and/or provided with interchangeable accessory elements, so as to adapt to a particular object, e.g. a metallic conductor to be cut.
Most cutting operations, in particular those performed on electric cables, are hindered by very narrow space conditions and are performed in conditions (of risk due to live electric conductors) which are potentially very dangerous for the operator and harmful for the tools. Consequently, the need is felt to configure the cutting tool so as to reach easily the electric cable to be cut and, at the same time, to reduce the risk of injury to the operator and to limit potential damage to the tool itself.
A further need is that of being able to perform, and control the result of, the cutting operations with appropriate rapidly in order to reduce the time needed to perform the job.
With particular reference to the cutting of electric conductors in environments which are difficult to access, e.g. in underground channels which can be accessed from road level or from ground level by means of a manhole or by means of a trench, the working safety needs, both real and perceived by the operator, have not yet been satisfied.
It is thus the object of the present invention to provide a system for cutting electric cables or the like with a hydrodynamic cutting tool having features such as to solve at least some of the drawbacks mentioned with reference to the prior art.
These and other objects are achieved by means of a cutting system as shown and described herein and recited in the independent claim. The dependent claims relate to advantageous embodiments.
According to an aspect of the invention, a cutting system with a hydrodynamic cutting tool comprises:
By virtue of the combination of:
In order to understand the invention and better appreciate its advantages, the description of some embodiments will be provided below by way of non-limiting example with reference to the figures, in which:
With reference to the figures, a cutting system 1 with a hydrodynamic cutting tool 2 comprises:
The cutting tool 2 comprises the pump 3, the pressure flexible tube 7, the working head 4 and possible accessories physically connected thereto. The remote control 8 is physically separate from the cutting tool 2 so as to allow a positioning of the remote control 8 at a safety distance from the cutting tool 2.
The actuation communication means 10 comprise an actuation wireless connection exceeding the safety distance, and also the cutting confirmation communication means 11 also comprise a cutting confirmation wireless connection and/or contactless cutting confirmation signaling means (e.g. acoustic or visual) which exceeds the safety distance.
Advantageously, the pressure flexible tube 7 and the hydraulic liquid are electrically insulating and the working head 4 is electrically isolated from the pump 3. Furthermore, the pump and the heads are connected to a ground connection. This protects the pumping unit from high voltage if live cables are cut (by mistake).
According to an embodiment (Figures from 6 to 13), the actuation communication means 10 comprise an actuation transmitter 12 connected to, and preferably either mounted on or housed on or in the remote control 8, as well as an actuation receiver 13 connected to and preferably either mounted or housed on the pump 3, which together constitute the aforesaid actuation wireless connection.
The actuation transmitter 12 and the actuation receiver 13 are preferably wireless radio wave, or alternatively infrared radiation or laser, transmitters/receivers and/or transceivers.
The direct wireless transmission between the remote control 8 and pump 3 is fast and requires a minimum number of transmission components.
According to an embodiment (
The cutting confirmation transmitter 14 and the cutting confirmation receiver 15 are preferably wireless radio wave, or alternatively infrared radiation or laser, transmitters/receivers and/or transceivers.
The direct wireless transmission between the cutting detector 9 and the remote control 8 is fast and requires a minimum number of transmission components.
According to an embodiment (Figures from 7 to 13), either alternatively or in addition to the embodiment described with reference to
Also in this case, the cutting confirmation transmitter 14 and the cutting confirmation intermediate receiver 16 together make the aforesaid cutting confirmation wireless connection or at least one first wireless connection of a plurality of wireless connections, which together form the aforesaid cutting confirmation wireless connection.
The cutting confirmation transmitter 14 and the intermediate cutting confirmation receiver 16 are preferably wireless radio wave, or alternatively infrared radiation or laser, transmitters/receivers and/or transceivers.
The cutting confirmation intermediate receiver 16 facilitates the transmission of information on cutting completion in case of low transmission power, high transmission distances, tortuous transmission paths and in the presence of wireless transmission obstacles, e.g. opaque or radio-opaque structures or geological formations.
According to an embodiment (
The cutting confirmation intermediate transmitter 18 and the cutting confirmation receiver 15′ are preferably wireless radio wave, or alternatively infrared radiation or laser, transmitters/receivers and/or transceivers.
According to an embodiment (
The cutting confirmation intermediate transmitter 18 and the further cutting confirmation intermediate receiver 19 together make a second wireless connection of two wireless connections which together form the above-mentioned cutting confirmation wireless connection.
The further cutting confirmation intermediate transmitter 18 and the cutting confirmation intermediate receiver 19′ are preferably wireless radio wave, or alternatively infrared radiation or laser, transmitters/receivers and/or transceivers.
The further cutting confirmation intermediate receiver 19 further facilitates the transmission of information on cutting completion in case of low transmission power, high transmission distances, tortuous transmission paths and in the presence of wireless transmission obstacles, e.g. opaque or radio-opaque structures or geological formations.
According to a variant embodiment (
The first physical transmission line 20 is preferably electrically insulating and therefore not electrically conductive, and may include, for example, a Bowden cable, a torsional cable, a fluid-dynamic conductor or an optical fiber conductor.
The purpose of the first transmission line 20 is to provide cutting completion information from the cutting detector 9 to the pump 3, and may be provided instead of the aforesaid first cutting confirmation wireless connection, described above, i.e. of the cutting confirmation transmitter 14 and of the cutting confirmation intermediate receiver 16 (
Instead of the cutting confirmation intermediate receiver 16, conversion means 21 may be provided, e.g. an electrical or electronic switching circuit, connected between the first transmission line 20 and the cutting confirmation intermediate transmitter 18 and adapted to convert the pulse or signal supplied by the first transmission line 20 into a corresponding electrical signal and to transmit the corresponding electric signal to the intermediate cutting confirmation transmitter 18 and/or to a control electronics of the pump 3.
According to a further embodiment (
The auxiliary receiving station 22 may have the further features described above with reference to the intermediate receiving station 17, except for the separation of the cutting tool 2, and the auxiliary receiving station 22 and the intermediate receiving station 17 may be performed by a single device.
According to embodiments (Figures from 6 to 15), the cutting confirmation communication means 11 comprise optical and/or acoustic signaling means 24, which are activated in response to the reception of the cutting completion confirmation signal so as to alert the operator.
The signaling means 24 may comprise a light indicator, e.g. LED and/or an optical display and/or an acoustic indicator, e.g. a beeper, arranged in the remote control 8 (
The signaling means 24 may comprise a light indicator, e.g. an LED group or a very bright light source, preferably directional, e.g. a main beam light and/or an acoustic indicator, also preferably powerful in the order of an automotive horn, arranged on the pump 3 (
By virtue of the signaling means 24, the operator is immediately alerted that the cut has been completed and can proceed promptly with the successive step of working, in particular with the deactivation of the pump 3, without needing to leave his or her sheltered position distanced from working region.
According to an advantageous embodiment, the cutting completion signal is also automatically transmitted to the control electronics of the pump 3 which controls the completion and ending of the working cycle (cutting cycle) according to the cutting completion signal.
In particular, the control electronics of the pump 3, once cutting completion is confirmed (which corresponds to the reaching of the closed position of the jaws 5, 6=first working cycle interruption criterion), automatically interrupts the further pressurization of the hydraulic fluid, in particular, deactivates pump 3. This avoids an unnecessary further increase of the pressure of the hydraulic fluid, of the mechanical stress of the head and the electric power consumption of the battery, after the cut has been already completed, until a maximum pressure is reached which causes the opening of a maximum pressure valve (second working cycle interruption criterion) or until predetermined operating condition combinations occur.
According to embodiments, the cutting completion confirmation signal transmission to the pump 3 control electronic may be performed:
Either alternatively or additionally, a transmission of a pumping interruption command to the electronic control of the pump 3 may be brought about by the operator, in non-automatic manner, by means of manual actuation (of a button) of the remote control 8, and with the help of the actuation transmitter 12 and of the actuation receiver 13.
In embodiments (
The station actuation transmitter 25 and the station actuation receiver 26 are preferably wireless radio wave, or alternatively infrared radiation or laser, transmitters/receivers and/or transceivers.
The described transmitters and receivers are connected to the control electronics of the modules with which they are associated and can be controlled by these control electronics in a known manner and therefore not described in detail. Furthermore, the described transmitters and receivers can be separate devices and dedicated only to the described functions. This allows the use of low-cost, commercially available, wireless transmission systems, in particular wireless radio transmission, optimized for certain functions, such as a push-switch displacement sensor with the switch pushing confirmation radio transmitter aboard and with a dedicated radio receiver, of small size and low cost.
Alternatively, the described transmitters and receivers can be made by using more versatile transmitters, receivers or transceivers which perform a plurality of the described wireless transmission and receiving features.
For example, the remote control 8 may comprise a transceiver which performs the functions of the transmitters and receivers 12, 15 or 12, 15, 25. Similarly, the pump 3 may comprise a transceiver which performs the functions of the transmitters and receivers 13, 16 or 13, 16, 18. Again similarly, the intermediate receiving station 17 may comprise a transceiver which performs the functions of the transmitters and receivers 16, 26 or 16, 26, 18 or 19, 26.
According to an embodiment, the pump 3 comprises:
The hydrodynamic pump 31 comprises a tank 33, a pumping cylinder-piston assembly and a maximum pressure valve 34.
The pumping cylinder-pump assembly may comprise a pumping cylinder with an intake opening connected to the tank 33 by means of a check valve, which allows the flow of hydraulic oil from the tank 33 into the pumping cylinder, and a discharge opening in communication with the pressure flexible tube 7 and, consequently, with an actuation cylinder 35 of the working head 4. A check valve is arranged in the discharge opening to allow the flow of hydraulic oil from the pumping cylinder towards the actuation cylinder 35, but not the other way. In the pumping cylinder there may be accommodated a pumping piston coupled so as to translate together with a pivoting member actuated by the electric motor 30.
The maximum pressure valve 34 may be arranged in a return pipe 36 which connects the actuation cylinder 35 to the tank 33.
In this manner, the actuation of the electric motor 30 operates the hydrodynamic assembly 31 (pumping assembly) and moves the jaws 5, 6 from the open position either towards or into the closed position until a predetermined maximum calibration pressure is reached in the actuation piston 35. When the maximum calibration pressure is reached, the maximum pressure valve 34 automatically opens the fluid return pipe 36 to discharge (at least part of) the pressure liquid from the actuation cylinder 35 into the tank 33.
The working head 4 may comprise a body 37 with the actuation cylinder 35 which receives an actuation piston 38 which can be displaced by the pressurized fluid.
The working head 4 further comprises the two jaws 5, 6 connected to the body 37 in mutually movable manner and connected to the actuation piston 38 so that, in response to the displacement of the actuation piston 38, the jaws 5, 6 perform a relative movement between an open position and a closed position to perform the cutting.
A return spring 39 acts on the actuation piston 38 so as to elastically bias it to a rest position, in which the jaws 5, 6 are in the open position.
The working head 4 is removably connectible to the pressure pipe 7. Either alternatively or additionally, the pressure flexible tube 7 may be removably connected to the pump housing 27.
The cutting detector 9 is connected to the working head 4 so as to detect the arrival of one or both cutting jaws 5, 6 in the closed position or the arrival of the actuation piston 38 in the end-of-stroke position corresponding to the closed position of the jaws 5, 6. The cutting detector may comprise an electromechanical sensor, e.g. a position switch, an optical switch, a magnetic proximity sensor, contact sensor or a potentiometer.
Advantageously, the cutting detector 9 comprises a movable member 40, which is displaced (by at least one of the jaws 5, 6 or by the actuating piston 38) when the closed position of the jaws 5, 6 is reached and a part of the displacement energy of the movable member 40 is used to energize and actuate the cutting confirmation transmitter 14. Preferably, a further part of the displacement energy of the movable member 40 is accumulated for the reception, by the cutting confirmation transmitter 14, of a confirmation signal (from the cutting confirmation receiver 15, 15′) that the first cutting confirmation signal was received and, in the negative case, to repeat the transmission of the cutting confirmation signal.
The need for an electric battery for the cutting detector 9 is avoided in this manner.
In this embodiment, the cutting confirmation transmitter 14 and the cutting confirmation receiver 15, 15′ are configured as transceivers.
The hand-held remote control 8 comprises a control panel 41 for manually switching on and off (the electric motor 30 of) the pump 3.
In an embodiment, the control panel 41 also allows the manual selection of an operating mode of the pump 3 from a plurality of preset operating modes, and the hand-held remote control 8 may comprise a display which shows the selected operating mode and/or the operating parameters and/or information on the cutting execution state.
In an embodiment, the intermediate receiving station 17 is portable, preferably of medium-to-small size, e.g. in the order of 15 cm×15 cm×15 cm, but sufficiently large to be clearly visible at a distance from 5 m to 15 m. The intermediate receiving station 17 may comprise its own battery, preferably rechargeable, and an electronic control circuit connected with and configured to manage and control the battery, the receivers and/or the transmitters 16, 26, 18 aboard the intermediate station 17 and the signaling means 24.
In an embodiment, the working head 4 may comprise compression jaws instead of the described cutting jaws 5, 6, and thus be adapted to compress cables or electrical connections or other workpieces with the same features described with reference to the cutting of cables. The cut detector and the cutting completion signals described herein will act respectively as compression sensor and as a compression completion signal.
Number | Date | Country | Kind |
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102016000124520 | Dec 2016 | IT | national |