Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
  • F15B15/20—Other details, e.g. assembly with regulating devices
  • F15B15/28—Means for indicating the position, e.g. end of stroke
  • F15B15/2815—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT
  • F15B15/2861—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT using magnetic means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
  • F15B15/20—Other details, e.g. assembly with regulating devices
  • F15B15/28—Means for indicating the position, e.g. end of stroke
  • F15B15/2807—Position switches, i.e. means for sensing of discrete positions only, e.g. limit switches

Definitions

• the present invention relates to a fluid- operated device.
• the fluid- operated devices of known type comprise a work assembly provided with a liner and a stem inserted at least partly inside the liner and coupled to the latter in a sliding manner between at least one pair of opposite end-of-stroke extremes defining the maximum stroke of the stem with respect to the liner.
• the machines or the systems using this type of fluid- operated devices need to monitor the position of the stem with respect to the liner, e.g. to ensure the correct operation of these machines or systems.
• the known fluid- operated devices are provided with means for detecting the position of the stem with respect to the liner.
• these fluid- operated devices of known type comprise sensing means provided with at least one reference element associated with the stem at a preset position and at least one sensor element associated with the liner at one end-of- stroke extreme and adapted to detect the presence/absence of the reference element.
• the position of the stem with respect to the liner may be determined.
• the use of magnetic, inductive, optical sensors or the like is known so that the reference element associated with the stem can be detected without contact.
• the sensing means do not interfere in any way with the sliding of the stem inside the liner.
• the fluid-operated devices of this type are subject to improvements related to the detection accuracy of the position of the stem with respect to the liner.
• the sensor element does not always detect the reference element with the desired precision.
• the reference element stimulates the sensor element for an extremely limited time and does not always allow the correct recognition of the stem position with respect to the liner.
• the sensor elements only allow conveying status signals and therefore need to be operationally connected to signal control systems configured to interpret the status signals and consequently carry out one or more preset operations.
• the main aim of the present invention is to devise a fluid- operated device that allows detecting without contact and with greater reliability one or more predefined stem positions with respect to the liner with respect to the fluid- operated devices of known type.
• a further object of the present invention is to devise a fluid- operated device that allows the structure of the device itself to be considerably simplified with respect to the devices of known type.
• An additional object of the present invention is to devise a fluid- operated device that allows directly conveying the power signals.
• Another object of the present invention is to devise a fluid- operated device that allows to overcome the above mentioned drawbacks of the prior art within a simple, rational, easy, effective to use and affordable solution.
• Figure 1 is a sectional view of a device embodiment according to the invention in a first configuration of work
• Figure 2 is a sectional view of the device embodiment shown in Figure 1 in a second configuration of work
• Figure 3 is a sectional view of a component of the device embodiment shown in Figures 1 and 2;
• Figure 4 is a sectional view of a device embodiment variant shown in Figures 1 and 2;
• Figure 5 is an exploded view of a detail of the device shown in Figure 4.
• Figure 6 is a view of a device component shown in Figures 4 and 5;
• Figure 7 is a sectional view of the component shown in Figure 6;
• Figure 8 is a sectional view of a component embodiment variant shown in Figure 7;
• Figure 9 is a sectional view of a variant of the device embodiment shown in Figure 4.
• Figure 10 is a sectional view of a component of the device embodiment variant shown in Figure 9;
• Figure 11 is a sectional view of a further variant of the device embodiment shown in Figures 1 and 2;
• Figure 12 is a sectional view of a further embodiment of the device according to the invention.
• Figure 13 is a sectional view of a variant of the device embodiment shown in Figure 12;
• Figure 14 is a sectional view of a variant of the device embodiment shown in Figure 12;
• Figure 15 is a sectional view of an additional embodiment of the device according to the invention.
• Figure 16 is a sectional view of a component of the device embodiment shown in Figure 15 in the home configuration
• Figure 17 is a sectional view of the component shown in Figure 16 in the active configuration
• Figure 18 is a sectional view of an additional embodiment of the device according to the invention.
• Figure 19 is a sectional view of a component of the device embodiment shown in Figure 18 in the home configuration
• Figure 20 is a sectional view of the component shown in Figure 19 in the active configuration.
• reference numeral 1 globally indicates a fluid- operated device.
• the fluid- operated device 1 comprises:
• At least one work assembly 53 supplied by at least one work fluid and provided with:
• At least one stem 2 coupled in a sliding manner inside the liner 3 and defining with the latter a thrust chamber 4 of the work fluid for the movement of the stem 2 with respect to the liner 3 longitudinally along a direction of movement A;
• the work assembly 53 is of the type of a pneumatic or hydraulic member of a type known to the expert in the field, such as e.g. a pneumatic or hydraulic stem/piston pair.
• the sensing device 55, 55a, 55b comprises interaction means 54 interposed between the sensing element 5 and the stem 2 and movable without contact by the passage of the stem 2 between at least one home configuration, wherein the sensing element 5 detects one of either the presence or the absence of the stem 2 at the predefined position, and at least one active configuration, wherein the sensing element 5 detects the other of either the presence or the absence of the stem 2 at the predefined position.
• the interaction means 54 comprise at least one sliding chamber 6 and at least one sliding body 7 inside the sliding chamber 6.
• the sliding body 7 is moved close to the sensing element 5, which detects at least one of either the presence or the absence of the stem 2, and, in the active configuration, it is moved away from the sensing element 5, which detects the other of either the presence or the absence of the stem 2.
• the sliding chamber 6 faces the thrust chamber 4 without trespassing upon it.
• the sliding chamber 6 is interposed between the thrust chamber 4 and the sensing element 5.
• interaction means 54 comprise magnetic means 15, 16, 47, 51, 58 associated integral in translation with the sliding body 7 and adapted to operate in conjunction with the stem 2 to move the interaction means 54 between the home configuration and the active configuration.
• the stem 2 comprises at least one reference element 57 adapted to operate in conjunction with the magnetic means 15, 16, 47, 51, 58 to move the interaction means 54 between the home configuration and the active configuration.
• the magnetic means 15, 16, 47, 51, 58 may be forced back or attracted by the stem 2 and consequently cause the sliding body 7 to move inside the sliding chamber 6.
• the interaction means 54 comprise at least one resilient element 8 interposed between the sliding chamber 6 and the sliding body 7.
• the resilient element 8 is loaded when the interaction means 54 are in one of either the home configuration or the active configuration, bringing the latter back into the other of either the home configuration or the active configuration.
• the resilient element 8 is unloaded when the interaction means 54 are in the other of either the home configuration or the active configuration, maintaining the interaction means 54 in the same configuration.
• the sliding chamber 6 defines a sliding channel 59 inside which the sliding body 7 slides.
• the interaction means 54 comprises at least one housing section 9 of the resilient element 8 made on the sliding body 7.
• the resilient element 8 is preferably a spring housed at least partly inside the housing section 9 and wound at least partly around the sliding body 7.
• the sliding body 7 comprises at least one elongated portion 10 facing the thrust chamber 4 and at least one enlarged portion 11 opposite the elongated portion 10 and associated with the latter to define with the latter a stop section 12 of the resilient element 8 wound around the elongated portion 10.
• the stop section 12 is arranged, in use, substantially opposite the housing section 9.
• the resilient element 8 is interposed between the housing section 9 and the stop section 12, so as to be loaded when the sliding body 7 is moved close to the sliding chamber 6, and unloaded when the sliding body 7 is moved close to the sensing element 5.
• the resilient element 8 counteracts the movement of the sliding body 7 caused by the magnetic means 15, 16, 47, 51, 58, which, during the movement of the stem 2, move the sliding body 7 along the sliding chamber 6 and consequently move the interaction means 54 from the home configuration to the active configuration.
• the sliding body 7 comprises at least a first ending portion 13 facing the sliding chamber 6 and at least a second ending portion 14 opposite the first ending portion 13.
• the magnetic means 15, 16, 47, 51, 58 comprise at least a first magnetic element 15 associated with the first ending portion 13 and at least a second magnetic element 16 associated with the second ending portion 14.
• the first magnetic element 15 is adapted to operate in conjunction with the stem 2 to move the interaction means 54 between the home configuration and the active configuration.
• the second magnetic element 16 is adapted to operate in conjunction with the sensing element 5 to detect the presence/absence of the stem 2 in the proximity of the predefined position during the movement of the interaction means 54 between the home configuration and the active configuration.
• the first magnetic element 15 is a permanent magnet.
• the second magnetic element 16 is preferably a permanent magnet.
• the first magnetic element 15 faces outwards from the first ending portion 13 towards the thrust chamber 4, as shown in Figures 1 and 2.
• the second magnetic element 16 faces outwards from the second ending portion 14 towards the sensing element 5.
• the magnetic field exerted by the first and the second magnetic elements 15, 16 is not hindered by the sliding body 7.
• the first ending portion 13 preferably coincides with the elongated portion 10 and the second ending portion 14 preferably coincides with the enlarged portion 11.
• the elongated portion 10 and consequently the first magnetic element 15 is arranged, in use, in the proximity of the stem 2, thus facilitating the interaction with the latter.
• the stem 2 comprises at least one piston 17 sliding tightly inside the liner 3, and the reference element 57 is made of one of a ferrous, magnetic and non magnetic material and coincides with the piston 17.
• the stem 2 comprises an elongated body 18 locked together in shifting motion with the piston 17 to form the stem itself.
• the piston 17 corresponds to the end of the stem 2 arranged inside the thrust chamber 4 and the elongated body 18 is movable in a sliding manner inside and outside the thrust chamber 4, as shown in Figure 1 and Figure 2.
• the reference element 57 operates on the first magnetic element 15, which causes the sliding body 7 to move.
• the piston 17 is made of ferrous material and operates on the first magnetic element 15 by attracting it to itself.
• the sliding body 7 is attracted to the piston 17 and moves the second magnetic element 16 away from the reference element 57, thus causing the interaction means 54 to move from the home configuration to the active configuration.
• the first magnetic element 15 is attracted or forced back by the reference element 57 depending on the polarity of the magnetic pole of the reference element 57 facing the first magnetic element 15.
• the stem 2 when the reference element 57 is made of non-magnetic material, the remaining part of the stem 2 is made at least partly of ferrous or magnetic material. This way, the stem 2, during its movement, operates on the first magnetic element 15 by forcing it back/attracting it, except for the point at which the reference element 57 faces the first magnetic element 15.
• the sensing element 5 is a magnetic sensor configured to detect the magnetic field exerted by the magnetic means 15, 16, 47, 51, 58 and to sense the variation thereof during the movement of the interaction means 54 between the home configuration and the active configuration.
• the second magnetic element 16 is moved close to the sensing element 5, i.e. the magnetic sensor, which detects the magnetic field emitted by the second magnetic element 16 so as to signal the presence/absence of the stem 2 at the predefined position.
• the second magnetic element 16 is moved away from the sensing element 5 to signal the presence/absence of the stem 2 at the predefined position.
• Embodiment variants not shown in the figures, cannot however be ruled out wherein the magnetic means 15, 16, 47, 51, 58 comprise a single magnetic element associated with the sliding body 7 and facing outwards from the latter at the first and second ending portion 13, 14.
• the interaction means 54 comprise at least one ferromagnetic element 19 interposed between the sliding body 7 and the sensing element 5 and adapted to intensify the magnetic field exerted by the magnetic means 15, 16, 47, 51, 58 on the sensing element 5 in the home configuration.
• the interaction means 54 comprise at least one housing hole 20 made on the sliding chamber 6 and interposed between the sliding body 7 and the sensing element 5, as shown in Figure 3.
• the housing hole 20 is preferably of the through hole type, and the ferromagnetic element 19 is accommodated to size inside the housing hole 20 and consequently faces the second magnetic element 16 and the sensing element 5 at the same time.
• the ferromagnetic element 19 given its nature, guides the magnetic field lines emitted by the second magnetic element 16 towards the sensing element 5, promoting the latter to sense the magnetic field emitted by the second magnetic element 16.
• the device 1 comprises at least one inlet port 23 of the work fluid inside the thrust chamber 4 associated with the liner 3 and centered along a direction of connection D.
• FIG 4 an embodiment variant of the device 1 is shown in Figure 4, wherein the sensing device 55, 55a, 55b is associated with the inlet port 23 and defines at least one connecting channel 56 provided with at least a first connecting head 68 facing the inlet port 23 and at least one second connecting head 69 opposite the first connecting head 68 and facing a supply source 39 of the work fluid.
• connection D connects the inlet port 23 to the supply source 39 in a fluid- operated manner along the direction of connection D.
• the inlet port 23 is centered along a direction of connection D arranged substantially transverse to the direction of movement A.
• the direction of connection D is orthogonal to the direction of movement A.
• connecting channel 56 extends, preferably, substantially straight along the direction of connection D to connect the inlet port 23 to the supply source 39 in a fluid- operated manner along the direction of connection D.
• the device 1 comprises at least one pair of inlet ports 23 of the work fluid associated with the liner 3 in fluid- operated communication with the thrust chamber 4 and adapted to supply the latter with the pressurized work fluid.
• the inlet port 23 preferably defines a supply duct 24 through which the work fluid flows.
• the supply duct 24 extends longitudinally and substantially centered along the direction of connection D.
• the sensing device 55, 55a, 55b is at least partly associated inside the supply duct 24.
• the connecting channel 56 comprises at least a first opening for the passage of the work fluid made at the first connecting head 68 and at least a second opening for the passage of the work fluid made at the second connecting head 69.
• the connecting channel 56 conveys the work fluid provided by the supply source 39 to the inlet port 23 and, consequently, to the thrust chamber 4.
• the sensing device 55, 55a, 55b defines a plurality of connecting channels 56 substantially parallel to each other.
• the sliding chamber 6 extends substantially parallel to the connecting channel 56.
• the sliding chamber 6 and the connecting channel 56 are insulated from each other, i.e. the sliding body 7 is sealed inside the sliding chamber 6 and works dry.
• the device 1 comprises at least one of:
• removable association means 61, 62 of the sensing device 55, 55a, 55b with the inlet port 23 comprising at least a first associating portion 61 formed on the inlet port 23 and at least a second associating portion 62 formed on the sensing device 55, 55a, 55b, the first and the second associating portion 61, 62 being coupleable to each other along the direction of connection D; and removable connection means 63, 64 of the sensing device 55, 55a, 55b to the supply source 39 comprising at least a first connecting portion 63 formed on the sensing device 55, 55a, 55b and at least a second connecting portion 64 formed on the supply source 39, the first and the second connecting portion 63, 64 being coupleable to each other along the direction of connection D.
• the device 1 comprises both the association means 61, 62 and the connection means 63, 64.
• the sensing device 55, 55a, 55b comprises at least a first end 65 arranged, in use, facing the thrust chamber 4, and at least a second end 66 opposite the first end 65.
• the second associating portion 62 is preferably made at the first end 65.
• the first associating portion 61 is made inside the supply duct 24.
• first associating portion 61 is preferably a threaded profile and the second associating portion 62 is a nut screw profile adapted to couple to the threaded profile in a removable manner.
• the first end 65 in use, is fastened at least partly removable inside the supply duct 24 by means of the association means 61, 62.
• the sliding chamber 6 protrudes at least partly outside the first end 65 along the direction of connection D, as shown in Figs. 4, 5 and 7.
• the first connecting portion 63 is made at the second end 66.
• the second end 66 defines a connecting seat 67 inside which the supply source 39 is insertable in a removable manner.
• the connecting seat 67 preferably extends substantially centered and along the direction of connection D.
• the second connecting portion 64 is made on the supply source 39.
• first connecting portion 63 is preferably a threaded profile and the second connecting portion 64 is a nut screw profile adapted to couple in a removable manner with the threaded profile.
• the first connecting portion 63 is conveniently made inside the connecting seat 67.
• the supply source 39 in use, is fastened in a removable manner and at least partly inside the connecting seat 67 by means of the connection means 63, 64.
• the sensing device 55, 55a, 55b is coupled to the work assembly 53 interposed directly between the inlet port 23 and the supply source 39.
• the device 55, 55a, 55b made this way considerably reduces the overall dimensions of the device 1 with respect to the known type of devices, without significantly changing the connection between the inlet port 23 and the supply source 39.
• FIG. 8 An embodiment variant of the device 1 is shown in Figure 8, wherein the magnetic means 15, 16, 47, 51, 58 comprise at least one attractive element 51 associated with the sliding chamber 6 and facing the second magnetic element 16, wherein the attractive element 51 attracts the second magnetic element 16 to move the interaction means 54 between the home configuration and the active configuration.
• the sliding chamber 6 comprises at least one extreme wall 52 facing the second ending portion 14 and with which the attractive element 51 is associated.
• the attractive element 51 is associated with the extreme wall 52 and is arranged inside the sliding chamber 6.
• this embodiment variant differs from the previous one in that it does not require the use of the resilient element 8.
• the functions performed by the resilient element 8 are carried out by the second magnetic element 16 operating in conjunction with the attractive element 51.
• the sliding body 7 is moved close to the sensing element 5.
• the attractive element 51 attracts the second magnetic element 16 to itself, thus causing the sliding body 7 to move away from the stem 2.
• the first magnetic element 15 faces the reference element 57, which attracts the sliding body 7 to itself.
• the attractive effect between the first magnetic element 15 and the reference element 57 is greater than the attractive effect between the second magnetic element 16 and the attractive element 51.
• the second magnetic element 16 suffers the attractive effect by the attractive element 51 ; this effect, in fact, causes the movement of the interaction means 54 from the work configuration to the home configuration when the reference element 57 is moved away from the first magnetic element 15.
• sensing devices 55, 55a, 55b are associated with the liner 3 outside the inlet port 23, as shown in Figure 1.
• the device 1 cannot be ruled out, wherein it comprises a pair of inlet ports 23 and a single sensing device 55, 55a, 55b coupled to one of the ports themselves, as shown in Figure 13.
• FIG. 11 A further embodiment variant of the device 1 is shown in Figure 11.
• this embodiment variant differs from the previous ones in that the interaction means 54 comprise at least one passage channel 21 made on the sliding chamber 6 facing the thrust chamber 4 and adapted to allow the passage of the work fluid between the sliding chamber 6 and the thrust chamber 4.
• the work fluid increases the inertia of the sliding body 7, which is thus made less sensitive to external stresses, such as e.g. vibrations and shocks, which operate on the device 1, thus reducing the risk of undesired switches of the interaction means 54.
• a shock of the device 1 could force the movement of the sliding body 7, e.g., from the home configuration to the active configuration regardless of whether or not the reference element 57 faces the first magnetic element 15 or not.
• the device 1 comprises a pair of sensing devices 55a, 55b.
• the work assembly 53 comprises at least one pair of end-of-stroke extremes 22a, 22b opposite and spaced apart from each other to substantially define the stroke of the stem 2 with respect to the liner 3 along the direction of movement A.
• the piston 17 is movable inside the liner 3 between the end-of-stroke extremes 22a, 22b.
• each of the sensing devices 55a, 55b is arranged at a respective end-of-stroke extreme 22a, 22b to detect the position of the stem 2 with respect to the liner 3.
• each sensing element 5 detects when the stem 2, in this case the piston 17, reaches a corresponding end-of-stroke extreme 22a, 22b.
• the inlet ports 23 of the work fluid are associated in the proximity of the end-of- stroke extremes 22a, 22b to allow the movement of the stem 2 along the direction of movement A.
• the operation of the embodiment of the device 1 described above is as follows.
• the piston 17 is arranged at the predefined position of the sensing device 55a.
• the interaction means 54 of the sensing device 55a are in the active configuration.
• the sliding body 7 of the sensing device 55a is moved close to the stem 2 due to the attraction between the first magnetic element 15 and the piston 17, which in this embodiment coincides with the reference element 57.
• the resilient element 8 is loaded and the second magnetic element 16 is moved away from the ferromagnetic element 19 and from the sensing element 5, which does not sense, or senses below a preset threshold value, the magnetic field emitted by the second magnetic element 16.
• the sensing element 5 detects that the piston 17 is arranged at the end-of-stroke extreme 22a defining the configuration wherein the stem 2 is totally retracted inside the liner 3, as shown in Figure 1.
• the second magnetic element 16 of the sensing device 55b is moved close to the sensing element 5, which senses, or senses beyond a preset threshold value, the magnetic field thereof.
• both devices 55a, 55b are in the home configuration.
• the sensing element 5 detects that the piston 17 is arranged at the end- of- stroke extreme 22b defining the configuration wherein the stem 2 is totally extracted from the liner 3, as shown in Figure 2.
• FIG. 12 A further embodiment of the device 1 is shown in Figure 12, wherein the stem 2 comprises:
• At least one shifting body 25 with respect to the liner 3 along the direction of movement A made of one of a ferrous, magnetic and non-magnetic material and operating in conjunction with the magnetic means 15, 16, 47, 51, 58 to move the interaction means 54 to one of the home configuration and the active configuration;
• reference elements 57 associated with the shifting body 25 spaced apart from each other along the direction of movement A at a plurality of respective pre-established positions and arranged, in use, facing the sliding chamber 6, the reference elements 57 being made of another of the ferrous, magnetic and non-magnetic material and operating in conjunction with the magnetic means 15, 16, 47, 51, 58 to move the interaction means 54 to the other of the home configuration and the active configuration.
• the stem 2 comprises a piston 17 and the shifting body 25 coincides with the elongated body 18.
• the piston 17 does not comprise a reference element 57, neither coincide therewith.
• the piston comprises in turn one or more reference elements 57 or wherein it coincides with the reference element itself.
• the shifting body 25 is made of ferrous material and the reference elements 57 are made of non-magnetic material.
• the shifting body 25 and the reference elements 57 are made of different materials, e.g. wherein the stem 2 and the reference elements 57 are made of a ferrous, magnetic and non-magnetic material, respectively.
• the sliding body 7 is moved close to the stem 2 whenever it is placed facing the shifting body 25.
• the sliding body 7 is moved away from the stem 2, due to the resilient element 8, whenever it faces a reference element 57 or whenever it does not face the stem 2.
• the interaction means 54 of the sensing device 55, 55a, 55b are in the active configuration when the latter faces the shifting body 25.
• the interaction means 54 of the sensing device 55, 55a, 55b are in the home configuration when the latter faces a reference element 57.
• each detection of a reference element 57 corresponds to a predefined reciprocal position of the stem 2 with respect to the liner 3.
• the sensing device 55, 55a, 55b allows constantly monitoring the position of the stem 2 with respect to the liner 3.
• the work assembly 53 comprises at least one guiding body 26 of the stem 2 through which the latter is coupled tightly to the liner 3 along the direction of movement A.
• the sensing device 55, 55a, 55b is inserted at least partly inside the guiding body 26.
• the work assembly 53 comprises at least one guiding channel 27 of the shifting body 25 made on the guiding body 26.
• the shifting body 25 is provided with a cross section that is substantially complementary to the guiding channel 27 and substantially smaller than that of piston 17, which, as a result, is constrained inside the thrust chamber 4 along the direction of movement A by the guiding body 26.
• the guiding body 26 defines the end-of-stroke extreme
• the piston 17 is shiftable in sliding contact with the liner 3 between the end-of-stroke extremes 22a, 22b.
• the shifting body 25 is shiftable in contact with the guiding body 26 inside and outside the thrust chamber 4.
• the sensing device 55, 55a, 55b is arranged inside the guiding body 26 facing the guiding channel 27.
• the sensing device 55, 55a, 55b is substantially placed side by side with the shifting body 25, thus increasing the effect of the latter and of the reference elements 57 on the magnetic means 15, 16, 47, 51, 58 of the same sensing device.
• this solution minimizes the distance between the shifting body 25 and the sliding body 7, thus increasing the sensitivity of the sensing device 55, 55a, 55b.
• the shifting body 25 is substantially cylindrical in shape and is provided with a plurality of grooves 28 made at the predefined positions.
• reference elements 57 are substantially ring-shaped and are associated to size inside the grooves 28 to define with the shifting body 25 a substantially cylindrical- shaped body.
• the work assembly 53 comprises sealing means 31, 32 interposed between the guiding body 26, the stem 2 and the liner 3 to delimit the sliding chamber 6.
• the sensing device 55, 55a, 55b is arranged outside or inside the thrust chamber 4.
• the sealing means 31, 32 define a wet stretch 29 and a dry stretch 30 of the guiding channel 27, where the wet stretch 29 coincides with a portion of the thrust chamber 4 and the dry stretch coincides with a stretch outside the thrust chamber 4.
• the sealing means 31, 32 comprise at least a first sealing element 31 interposed between the liner 3 and the guiding body 26 and at least a second sealing element 32 interposed between the guiding body 26 and the stem 2.
• the sensing device 55, 55a, 55b is arranged outside the thrust chamber 4.
• the sensing device 55, 55a, 55b is arranged at least partly inside the guiding body 26 and faces the dry stretch 30 of the guiding channel 27.
• the sensing device 55, 55a, 55b is arranged outside the inlet port 23 of the work fluid.
• FIG. 13 An embodiment variant of the device 1 is shown in Figure 13 wherein, the sensing device 55, 55a, 55b is arranged inside the thrust chamber 4.
• the sensing device 55, 55a, 55b is arranged at least partly inside the guiding body 26 and faces the wet stretch 29 of the guiding channel 27.
• the sensing device 55 is arranged inside an inlet port 23 of the work fluid.
• FIG. 14 A further embodiment variant of the device 1 is shown in Figure 14.
• this embodiment variant differs from the embodiment of the device 1 described above in that the device 1 comprises signaling means 60 for signaling the direction of movement of the stem 2 with respect to the liner 3, interposed between the sensing device 55, 55a, 55b and the stem 2 and provided with:
• At least one recess 33 made facing the stem 2 and defining with the latter a sliding duct 34 provided with at least one pair of stop ends 37a, 37b substantially opposite each other and between which the sliding duct 34 extends substantially parallel to the direction of movement A;
• the device 1 comprises a plurality of sensing devices 55, 55a, 55b, among which one of these is placed facing the dry stretch 30.
• the device 1 cannot however be ruled out wherein it comprises a single sensing device 55, 55a, 55b.
• the signaling means 60 are interposed between the sensing device 55, 55a, 55b is placed facing the dry stretch 30 and the stem 2, as shown in Figure 14.
• the recess 33 is formed on the guiding body 26 facing inside the guiding channel 27.
• the device 1 comprises an insert 36 obtained, preferably, on the guiding body 26, communicating with the recess 33 and inside which is housed the sensing device 55, 55a, 55b facing the recess itself at one of the stop ends 37a, 37b.
• the sensing device 55, 55a, 55b, the stem 2 and the recess 33 operate in conjunction with each other to define the sliding duct 34, as shown in Figure 14.
• the movable body 35 is constrained at the top and bottom, respectively, by the sliding chamber 6 and by the stem 2, and is constrained longitudinally along the direction of movement A between the stop ends 37a, 37b by the sliding duct 34.
• the movable body 35 is movable alternately along the direction of movement A in a forward direction B and in a backward direction C, which is substantially opposite the forward direction B.
• forward direction B indicates the direction of movement of the stem 2 along the direction of movement A outwards from the liner 3.
• backward direction C indicates the movement of the stem 2 along the direction of movement A inwards of the liner 3.
• the movable body 35 is moved in the forward direction B or in the backward direction C at the same time as the movement of the stem 2.
• the movable body 35 accompanies the movement of the stem 2 in the same direction of movement as the latter due to the sliding friction between the contact surfaces of the two.
• the movable body 35 has, preferably, a ring shape and defines a passage hole inside which the stem 2 is inserted to size. This way, when the stem 2 is moved to the forward direction B, the movable body 35 is moved close to the stop end 37b until it is forced to stop its stroke at the latter.
• the sensing device 55, 55a, 55b is arranged facing the sliding duct 34 at the stop end 37b.
• the movable body 35 is made of one of a ferrous, magnetic and non magnetic material.
• the movable body 35 is made of a magnetic material.
• the stem 2 does not drag the movable body 35 due to the sliding friction between the contact surfaces of the two.
• the corresponding sliding body 7 is moved close to the stem 2 due to the attraction between the movable body 35 and the first magnetic element 15, thus moving the interaction means 54 from the home configuration to the active configuration.
• the interaction means 54 of the sensing device 55, 55a, 55b switch from the home configuration to the active configuration when the movable body 35 is dragged by the stem 2 to the stop end 37b, i.e. when the stem 2 is moved in the forward direction B.
• the interaction means 54 of the sensing device 55, 55a, 55b switch from the active configuration to the home configuration, when the movable body 35 is moved away from the stop end 37b, as shown in Figure 14.
• the home configuration and the active configuration of the interaction means 54 of the sensing device 55, 55a, 55b facing the sliding duct 34 are related to the movement of the stem in the forward direction B or in the backward direction C, thus allowing the determination of the direction of movement of the stem 2.
• FIG. 15 A further embodiment of the device 1 is shown in Figure 15.
• this embodiment differs from the embodiments described above in that the sensing element 5 is of the type of a micro- switch and is provided with at least one switch element 42 operable mechanically for the activation of the same sensing element 5.
• the sliding body 7 comprises at least one extreme portion 49 facing the thrust chamber 4 and at least one activation extreme 38 opposite the extreme portion 49.
• the extreme portion 49 coincides with the first ending portion 13 described in the previous embodiments.
• the activation extreme 38 is moved close to the switch element 42 pressing it in one of the home configuration and the active configuration, and is moved away from the switch element 42 releasing it in the other of the home configuration and the active configuration.
• the magnetic means 15, 16, 47, 51, 58 comprise at least one magnetic body 47 associated with the extreme portion 49 and adapted to operate in conjunction with the stem 2 to move the interaction means 54 between the active configuration and the home configuration.
• the sensing element 5 i.e. the micro-switch, can directly convey the power signals.
• the sensing device 55, 55a, 55b comprises a pair of sensing elements 5, in this case micro- switches with changeover contacts, arranged opposite each other with respect to the sliding channel 59.
• the activation extreme 38 comprises at least one sliding shank 40 inside the sliding channel 59 and at least one activation shank 41 associated with the sliding shank 40 to define an activation extreme 38 having a substantially“T” shape.
• the activation shank 41 is arranged outside the sliding channel 59 facing the switch element 42, as shown in Figure 16 and 17.
• the conformation and use of the magnetic body 47 are similar to the conformation and use of the first magnetic element 15 described with reference to the previous embodiments.
• the resilient element 8 is interposed between the sliding channel 59 and the activation extreme 38.
• the interaction means 54 comprise at least one stop edge 48 obtained inside the sliding channel 59 and in which the resilient element 8 is housed.
• the resilient element 8 is preferably a spring wound at least partly around the sliding body 7 at the sliding shank 40 and interposed in abutment between the stop edge 48 and the activation shank 41, as shown in Figures 16 and 17.
• the operation of the embodiment of the device 1 described above is as follows.
• the interaction means 54 of the corresponding sensing device 55, 55a, 55b are in active configuration.
• the sliding body 7 of the sensing device 55, 55a, 55b is moved close to the stem 2 due to the attraction between the magnetic body 47 and the reference element 57.
• the activation shank 41 abuts against the switch element 42 and activates the sensing element 5.
• the resilient element 8 is loaded in this configuration.
• the sensing element 5 comprises an elastic return body, not shown in the figures, adapted to restore the status of the switch element 42 after the compression thereof by the activation shank 41.
• the compression of the switch element 42 causes the compression of the return elastic body, which, this way, is loaded and counteracts this compression, tending to return the switch element 42 to its original position.
• the elastic return body unloads and operates on the switch element 42 which in turn operates on the activation shank 41 by forcing it back, i.e. by moving it away from the sensing element 5.
• the use of the resilient element 8 is not provided.
• the functions performed by the resilient element 8 are carried out by the return elastic body of the sensing element 5.
• FIG. 18 A further embodiment of the device 1 is shown in Figure 18, wherein, unlike the embodiment variant described above, the magnetic means 15, 16, 47, 51, 58 comprise at least one attractive body 58 associated with the activation extreme 38 and facing the attractive element 51.
• the attractive element 51 and the attractive body 58 are configured to attract/force back each other to move the interaction means 54 between the home configuration and the active configuration.
• At least one of either the attractive element 51 or the attractive body 58 is made of magnetic material.
• the other of either the attractive element 51 or the attractive body 58 is made of one of either a magnetic material or a ferrous material.
• the attractive element 51 is made of a magnetic material and the attractive body 58 is made of a ferrous material.
• the device 1 is without the resilient element 8 and its operation is similar to that described with reference to the previous embodiment, in which, however, the functions performed by the resilient element 8 are carried out by the attractive element 51 operating in conjunction with the attractive body 58.
• the sensing devices 55, 55a, 55b shown in Figures 7, 8, 16, 17, 19 and 20 may be used as an alternative to the sensing devices 55, 55a, 55b used in the embodiments of the device 1 shown in Figures 4, 9, 11-14.
• the sensing of the intermediate positions of the stem 2 with respect to the liner 3, i.e. the repeated movement of the interaction means between the home configuration and the active configuration causes the mechanical activation/deactivation of the micro- switch, which, in turn, generates a train of electrical pulses particularly easy to control by a user with respect to the signal generated by the magnetic sensor.
• all the intermediate positions detected by the sensing devices 55, 55a, 55b are mechanically transduced.
• the maintenance, installation and control of the signals generated by the sensing elements 5 of the type of a magnetic sensor is particularly complex compared to the sensing elements 5 of the micro-switch type.
• the interaction means allow the fluid-operated device to detect one or more stem positions with respect to the liner with an extremely high precision compared to the fluid- operated devices of known type.
• the interaction means make it possible to detect the reference elements in a very simple, reliable and accurate way, regardless of whether they are associated at the piston or at intermediate stem positions.
• the use of the sensing devices provided with micro- switches makes it possible to directly convey the power signals without the need for auxiliary electronic signal conversion/processing systems.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
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• 2020
  • 2020-06-09 WO PCT/IB2020/055400 patent/WO2020250122A1/en unknown
  • 2020-06-09 EP EP20737278.0A patent/EP3983686A1/de not_active Withdrawn

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