US20040065194A1 - Device for dampening the oscillation of the arm of a handling equipment of the swingable lever type - Google Patents
Device for dampening the oscillation of the arm of a handling equipment of the swingable lever type Download PDFInfo
- Publication number
- US20040065194A1 US20040065194A1 US10/460,250 US46025003A US2004065194A1 US 20040065194 A1 US20040065194 A1 US 20040065194A1 US 46025003 A US46025003 A US 46025003A US 2004065194 A1 US2004065194 A1 US 2004065194A1
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- United States
- Prior art keywords
- cylinder
- rod
- stem
- cavity
- arm
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Classifications
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- 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
- F15B15/22—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke
- F15B15/227—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke having an auxiliary cushioning piston within the main piston or the cylinder end face
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- 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
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/06—Servomotor systems without provision for follow-up action; Circuits therefor involving features specific to the use of a compressible medium, e.g. air, steam
- F15B11/072—Combined pneumatic-hydraulic systems
- F15B11/076—Combined pneumatic-hydraulic systems with pneumatic drive or displacement and speed control or stopping by hydraulic braking
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- 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
- F15B15/08—Characterised by the construction of the motor unit
- F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
- F15B15/1423—Component parts; Constructional details
- F15B15/1466—Hollow piston sliding over a stationary rod inside the cylinder
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- 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/40—Flow control
- F15B2211/405—Flow control characterised by the type of flow control means or valve
- F15B2211/40507—Flow control characterised by the type of flow control means or valve with constant throttles or orifices
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- 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/40—Flow control
- F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
- F15B2211/41527—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a directional control valve
- F15B2211/41536—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a directional control valve being connected to multiple ports of an output member
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- 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
- F15B2211/7051—Linear output members
- F15B2211/7055—Linear output members having more than two chambers
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- 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/75—Control of speed of the output member
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- 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
- F15B2211/00—Circuits for servomotor systems
- F15B2211/80—Other types of control related to particular problems or conditions
- F15B2211/86—Control during or prevention of abnormal conditions
- F15B2211/863—Control during or prevention of abnormal conditions the abnormal condition being a hydraulic or pneumatic failure
Definitions
- the present invention refers in general to handling equipments of the so-called swingable lever type.
- the invention relates to a device for dampening the oscillation of the arm of a handling equipment of the swingable lever type, which equipment comprises a driving double acting cylinder having a chamber in which a main piston is sealingly mounted, which is slidable as a result of the selective delivery of fluid under pressure at opposite zones of the chamber of the cylinder, the main piston being connected to a rod having a driving end which projects from the cylinder and is associated with said arm.
- anomalous conditions of delivery of fluid under pressure to the chamber of the cylinder can take place, which may involve on the one hand risks to the integrity of the structure of such equipments and of the equipment associated with them, and on the other hand risks to the safety of operators who may be close to the equipments.
- braking devices which operate on the basis of the principle to apply a friction force against the outside surface of the rod in the case of a pressure drop.
- braking devices may be used which include planes inclined with respect to the cylinder axis, to which rollers or balls are associated, which are intended to interfere with the peripheral surface of the rod when a pressure drop below a predetermined threshold occurs.
- Other braking devices employ a reed member having a through circular hole in which the rod is inserted, whose diameter is little greater than that of the rod.
- the sheet member in the operation with the fluid fed under normal pressure, the sheet member is perpendicular to the axis of the rod, whereby the rod can slide axially through it.
- the reed member In the case of pressure drop, the reed member is placed in a configuration inclined with respect to the rod axis, so that an interference take place between the edges of its through hole and the radial surface of the rod, which causes the axial locking of the latter.
- the devices mentioned above for controlling the movement of the rod, and therefore the oscillation of the arm may turn out to be not very practical or not very reliable in use.
- their operation can be affected by the dimensions of the mechanical members involved in the operation, so that the wear of one of the members of the device can jeopardize their good operation, as well as the presence of foreign bodies, also if they are very small, in the fluid fed to the cylinder.
- such devices allow to lock the rod when it is moving along only one of its shifting directions, and require therefore to be doubled when the locking of the motion of the rod in both its shifting directions is desired.
- the main object of the present invention is therefore to provide a dampening device intended to fit out a handling equipment of the swingable lever type, which is able to prevent that malfunctions may occur in the case in which the anomalous feeding conditions mentioned above take place.
- the dampening device of the invention is marked by a simple and compact structure allowing to obtain an effective slowing down of the arm towards the end-of-travel positions, in the case in which an anomaly in the feeding of the cylinder takes place, keeping at the same time the hindrance and the weight of the equipment small, and allowing to limit its production costs.
- FIG. 1 is a schematic elevational side view of a swingable lever handling equipment provided with a dampening device according to the invention
- FIG. 2 is an enlarged cross-sectional view of a detail of the equipment indicated by the arrow II in FIG. 1, and
- FIG. 3 is a view similar to FIG. 2, showing a different working condition of the device.
- FIG. 1 With reference to the FIG. 1 indicates as a whole a handling equipment of the swingable lever type, which is operated by means of fluid under pressure, typically air.
- the equipment 1 comprises a body 3 to which a double acting fluid cylinder 5 is associated for driving a fork lever arm 7 by means of a toggle joint unit of a type known per se and not illustrated in the figures, which is contained inside the body 3 of the equipment 1 .
- the toggle joint unit allows to set in an oscillation motion a pair of coaxial crank pins 11 on which the branches 13 of the fork arm 7 are fitted, as from the reciprocating motion of a driving end 10 a of a rod 10 which is slidable with respect to the cylinder 5 .
- an attachment plate 13 a is fastened to the branches 13 , which is provided with holes and/or openings in order to allow to connect apparatuses (not shown in the figures) to be moved by the equipment 1 .
- a main piston 15 which is connected to the rod 10 , is slidably and sealingly mounted by annular seals 16 , inside a chamber 18 defined by the body of the cylinder 5 .
- the two opposite faces of the piston 15 have each an axial sleeve portion 15 a , 15 b , whose diameter is slightly wider than that of the rod 10 .
- the chamber 18 is axially defined by a pair of heads 20 a and 20 b , respectively higher and lower with reference to the figures.
- Respective feeding and exhaust lines 21 a , 21 b and 22 a , 22 b for the fluid under pressure are formed in each of the heads 20 a and 20 b .
- the lines 21 a and 21 b or 22 a and 22 b are selectively connected, by a switching device of a type known per se, with a source of fluid under pressure, in order to produce alternatively over-pressure conditions on one of the faces of the piston 15 , so as to cause the reciprocating motion of the piston 15 inside the chamber 18 between the heads 20 a and 20 b .
- Each of the lines 21 a , 21 b has preferably a pair of branch lines, one of which ends in the chamber 18 facing a respective face of the piston 15 , the other one ending into a seat 25 a , 25 b for receiving a respective sleeve portion 15 a , 15 b of the piston 15 when the piston is in an end-of-stroke position.
- a cylindrical cavity 27 is formed axially, in which an enlarged head 29 of a sliding stem 30 is slidably and sealingly mounted.
- the head 29 is provided with a peripheral seal 32 bearing on the sidewall of the cavity 27 .
- the end of the stem 30 opposite to that supporting the head 29 is rigidly connected to a support plate 34 anchored to the bottom of the cylinder 5 , for example by means of a plurality of axial screws (not illustrated in the figures).
- the cavity 27 is filled up with a service fluid, typically oil, and is separated with respect to the outer environment in order to prevent the discharge of such a liquid.
- a bored plug 36 which is screwed at the end of the rod 10 opposite to its driving end 10 a , is arranged on the side of the chamber 18 .
- the plug 36 is crossed centrally by the stem 30 , a ring-like seal 37 being interposed between the stem 30 and the plug 36 .
- an auxiliary piston 38 which will be considered in further detail in the following, is inserted in the axial cavity 27 .
- the piston 38 is provided with a ring-like seal 39 similar to the seal 37 of the bored plug 36 .
- the stem 30 is provided with orifice means for the service fluid, which are conveniently arranged at its end provided with the head 29 .
- These orifice means can consist of a longitudinal hole 31 opening at the end of the stem 30 facing the auxiliary piston 38 and connected with a calibrated transversal hole 31 a opening on the side of the enlarged head 29 facing the plug 36 .
- the enlarged head 29 of the stem 30 slides inside the cylindrical cavity 27 forcing the service fluid to flow through the orifice means constituted by the holes 31 and 31 a , so as to pass from a side to the other of the head 29 .
- the hole having the smaller cross-section of the orifice means that is the hole 31 a in the case illustrated in the figures but which could be otherwise the hole 31 , is dimensioned in such a way that, in the normal operation of the equipment 1 , the rod does not undergo any appreciable slowing down.
- the auxiliary piston 38 is mounted floating in the cavity 27 and it can be associated with elastic thrust means 40 , constituted by a coil spring, biasing it towards the stem 30 .
- elastic thrust means 40 constituted by a coil spring
- the auxiliary piston 38 is associated with guide means of its axial movement in the cavity 27 , comprising a pin 42 an end of which is fixed to the auxiliary piston 38 , while the opposite end is slidable in a corresponding seat 46 formed in proximity of the driving end 10 a of the rod 10 .
- the seat 46 communicates with the outer environment with respect to the cylinder 5 , by means of a vent hole 48 .
- adjusting means of the cross-section of the orifice means in which the service fluid passes can be arranged.
- a spindle (not illustrated in the figures) can be arranged in a coaxial hole inside the stem 30 and associated with the base of the stem 30 in proximity of the plate 34 by means of a threaded connection, which has a conical tip at his end facing the driving end of the rod 10 , in order to cooperate with a corresponding seat formed in a position adjacent to the hole 31 , for allowing the section of the hole to be changed as a result of the control of such a spindle by means of a tool which can be driven from the outside of the cylinder 5 .
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Actuator (AREA)
Abstract
A handling equipment of the swingable lever type comprises a driving double acting cylinder (5) having a chamber (18) in which a main piston (15) is sealingly mounted, which is slidable as a result of the selective delivery of fluid under pressure from opposite zones of the chamber (18) of the cylinder (5). The main piston (15) is connected to a rod (10) having a driving end (10 a) which projects from the cylinder (5) and is associated with a movable arm (7). The equipment (1) is provided with a device for dampening the oscillation of the arm (7), which comprises an axial cavity (27) formed in the rod (10) and containing a service fluid. A stem (30) rigidly connected to the cylinder (5) and provided with at least one orifice (31, 31 a) for the service fluid is sealingly and slidably mounted in the cavity (27), so that the movement of the rod (10) with respect to the stem (30) is slowed down as a consequence of the flowing of the service fluid through said orifice (31, 31 a), if the sliding speed of the main piston (15) inside the cylinder (5) exceeds a threshold speed set by the cross-section of said orifice (31, 31 a).
Description
- The present invention refers in general to handling equipments of the so-called swingable lever type.
- More particularly, the invention relates to a device for dampening the oscillation of the arm of a handling equipment of the swingable lever type, which equipment comprises a driving double acting cylinder having a chamber in which a main piston is sealingly mounted, which is slidable as a result of the selective delivery of fluid under pressure at opposite zones of the chamber of the cylinder, the main piston being connected to a rod having a driving end which projects from the cylinder and is associated with said arm.
- In known equipments of the type defined above, for example in pneumatic handling equipments, also called “tilter devices”, anomalous conditions of delivery of fluid under pressure to the chamber of the cylinder can take place, which may involve on the one hand risks to the integrity of the structure of such equipments and of the equipment associated with them, and on the other hand risks to the safety of operators who may be close to the equipments.
- These anomalous conditions are essentially of two kinds.
- A first anomalous condition can take place in the case in which, for example after a maintenance operation carried out on the equipment, the feeding and exhaust lines of the fluid under pressure are not correctly connected to the opposite ends of the cylinder, in particular if an end of the cylinder is connected with the feeding of the fluid under pressure while the other end freely communicates with the outer environment. When, in such conditions, the fluid under pressure is fed only to one of the cylinder ends, the piston moves violently against the cylinder end which is in communication with the outer environment, causing the arm of the equipment to fall down sharply to an end-of-travel position.
- Another anomalous condition occurs in the case of a pressure drop in the feeding line of the fluid under pressure to the cylinder, in particular if the oscillation axis of the arm of the equipment is not arranged vertically and if the piston has not reached as yet the end-of-stroke position in which the toggle joint associated with the rod makes irreversible its movement in the cylinder. In this case in fact, owing to the lack of a counter-pressure and under the weight of the apparatuses associated with the arm, it can fall down violently towards its lower end-of-travel position.
- In order to avoid the latter anomalous condition, devices for controlling the motion of the piston rod have been proposed, which operate on the basis of the principle to apply a friction force against the outside surface of the rod in the case of a pressure drop. For example, to this purpose braking devices may be used which include planes inclined with respect to the cylinder axis, to which rollers or balls are associated, which are intended to interfere with the peripheral surface of the rod when a pressure drop below a predetermined threshold occurs. Other braking devices employ a reed member having a through circular hole in which the rod is inserted, whose diameter is little greater than that of the rod. In the latter devices, in the operation with the fluid fed under normal pressure, the sheet member is perpendicular to the axis of the rod, whereby the rod can slide axially through it. In the case of pressure drop, the reed member is placed in a configuration inclined with respect to the rod axis, so that an interference take place between the edges of its through hole and the radial surface of the rod, which causes the axial locking of the latter.
- At any rate, the devices mentioned above for controlling the movement of the rod, and therefore the oscillation of the arm, may turn out to be not very practical or not very reliable in use. In fact, their operation can be affected by the dimensions of the mechanical members involved in the operation, so that the wear of one of the members of the device can jeopardize their good operation, as well as the presence of foreign bodies, also if they are very small, in the fluid fed to the cylinder. Moreover, such devices allow to lock the rod when it is moving along only one of its shifting directions, and require therefore to be doubled when the locking of the motion of the rod in both its shifting directions is desired. In practice, if inclined planes with rollers or balls are used, it will be necessary to provide inclined planes with respective rollers or balls for each of the shifting directions of the rod, while if bored reed members are used for locking the rod, two reed members, one for each shifting direction of the rod, will have to be provided.
- In both the anomalous feeding conditions of the cylinder considered above, the traditional swingable lever handling equipments risk to undergo serious damages which could jeopardize their operation and that of the apparatuses carried by their swingable arm, as well as to cause damages to possible people standing close to the equipments, if they are not equipped with devices adapted to prevent the arm to fall down in the event of an anomaly in the feeding of the fluid under pressure to the cylinder.
- The main object of the present invention is therefore to provide a dampening device intended to fit out a handling equipment of the swingable lever type, which is able to prevent that malfunctions may occur in the case in which the anomalous feeding conditions mentioned above take place.
- This object is attained thanks to the fact that an axial cavity separated from the cylinder chamber and containing a service fluid is formed inside the rod, a stem rigidly connected with the cylinder and provided with orifice means for the service fluid being sealingly and slidably mounted in such a cavity, so that the movement of the rod with respect to the stem is slowed down as a consequence of the flowing of the service fluid through the orifice means, if the sliding speed of the main piston inside the cylinder exceeds a threshold speed set by the cross-section of the orifice means.
- Thanks to these characteristics, the dampening device of the invention is marked by a simple and compact structure allowing to obtain an effective slowing down of the arm towards the end-of-travel positions, in the case in which an anomaly in the feeding of the cylinder takes place, keeping at the same time the hindrance and the weight of the equipment small, and allowing to limit its production costs.
- Further characteristics and advantages of the invention will become more clearly evident from the reading of the detailed description which follows, given purely by way of a non limiting example and referred to the attached drawings, in which:
- FIG. 1 is a schematic elevational side view of a swingable lever handling equipment provided with a dampening device according to the invention,
- FIG. 2 is an enlarged cross-sectional view of a detail of the equipment indicated by the arrow II in FIG. 1, and
- FIG. 3 is a view similar to FIG. 2, showing a different working condition of the device.
- With reference to the FIG. 1 indicates as a whole a handling equipment of the swingable lever type, which is operated by means of fluid under pressure, typically air.
- The equipment1 comprises a
body 3 to which a double actingfluid cylinder 5 is associated for driving afork lever arm 7 by means of a toggle joint unit of a type known per se and not illustrated in the figures, which is contained inside thebody 3 of the equipment 1. In brief, the toggle joint unit allows to set in an oscillation motion a pair ofcoaxial crank pins 11 on which thebranches 13 of thefork arm 7 are fitted, as from the reciprocating motion of a drivingend 10 a of arod 10 which is slidable with respect to thecylinder 5. Then, an attachment plate 13 a is fastened to thebranches 13, which is provided with holes and/or openings in order to allow to connect apparatuses (not shown in the figures) to be moved by the equipment 1. - A
main piston 15 which is connected to therod 10, is slidably and sealingly mounted byannular seals 16, inside achamber 18 defined by the body of thecylinder 5. The two opposite faces of thepiston 15 have each anaxial sleeve portion rod 10. - The
chamber 18 is axially defined by a pair ofheads exhaust lines heads lines piston 15, so as to cause the reciprocating motion of thepiston 15 inside thechamber 18 between theheads lines chamber 18 facing a respective face of thepiston 15, the other one ending into aseat respective sleeve portion piston 15 when the piston is in an end-of-stroke position. - In the
rod 10 acylindrical cavity 27 is formed axially, in which an enlargedhead 29 of asliding stem 30 is slidably and sealingly mounted. Thehead 29 is provided with aperipheral seal 32 bearing on the sidewall of thecavity 27. The end of thestem 30 opposite to that supporting thehead 29 is rigidly connected to asupport plate 34 anchored to the bottom of thecylinder 5, for example by means of a plurality of axial screws (not illustrated in the figures). - The
cavity 27 is filled up with a service fluid, typically oil, and is separated with respect to the outer environment in order to prevent the discharge of such a liquid. To this end, abored plug 36 which is screwed at the end of therod 10 opposite to its drivingend 10 a, is arranged on the side of thechamber 18. Theplug 36 is crossed centrally by thestem 30, a ring-like seal 37 being interposed between thestem 30 and theplug 36. - On the side of the
rod 10 close to thedrive end 10 a, anauxiliary piston 38 which will be considered in further detail in the following, is inserted in theaxial cavity 27. Thepiston 38 is provided with a ring-like seal 39 similar to theseal 37 of thebored plug 36. - Moreover, the
stem 30 is provided with orifice means for the service fluid, which are conveniently arranged at its end provided with thehead 29. These orifice means can consist of alongitudinal hole 31 opening at the end of thestem 30 facing theauxiliary piston 38 and connected with a calibratedtransversal hole 31 a opening on the side of the enlargedhead 29 facing theplug 36. - As a result of the sliding of the
piston 15 inside of thechamber 18, and therefore of therod 10 with respect to thehead 20 a, the enlargedhead 29 of thestem 30 slides inside thecylindrical cavity 27 forcing the service fluid to flow through the orifice means constituted by theholes head 29. The hole having the smaller cross-section of the orifice means, that is thehole 31 a in the case illustrated in the figures but which could be otherwise thehole 31, is dimensioned in such a way that, in the normal operation of the equipment 1, the rod does not undergo any appreciable slowing down. However, its cross-section is such as to involve a slowing down of therod 10 if the movement speed of the rod exceeds a prefixed threshold, owing to the viscous friction caused by the passage of the service fluid through theholes cylinder 5, had to be taken place, the excessive movement speed of therod 10 is slowed down owing to the passage of the service fluid through theholes stem 30, which causes a dampening of the oscillation of thearm 13 of the equipment 1. - In the case in which, as illustrated in the figures, the change of position of the enlarged
head 29 inside thecavity 27 involves a different extension of thestem 30 inside such a cavity, it is necessary to provide a device for compensating the longitudinal extension of thecavity 27, in view of the fact that the working volume for the service fluid must remain constant. To this end, theauxiliary piston 38 is mounted floating in thecavity 27 and it can be associated with elastic thrust means 40, constituted by a coil spring, biasing it towards thestem 30. However, it has been surprisingly found that thespring 40 can be eliminated without jeopardize the operation of the device, and concurring to reduce the number of the parts of the equipment and, consequently, its total cost. - Moreover, the
auxiliary piston 38 is associated with guide means of its axial movement in thecavity 27, comprising apin 42 an end of which is fixed to theauxiliary piston 38, while the opposite end is slidable in acorresponding seat 46 formed in proximity of the drivingend 10 a of therod 10. Preferably, theseat 46 communicates with the outer environment with respect to thecylinder 5, by means of avent hole 48. - In the case in which it is desirable to adjust the operating threshold of the dampening device, that is of the threshold speed of the
main piston 15 beyond which its sliding within thechamber 18 has to be slowed down, adjusting means of the cross-section of the orifice means in which the service fluid passes, can be arranged. For example, a spindle (not illustrated in the figures) can be arranged in a coaxial hole inside thestem 30 and associated with the base of thestem 30 in proximity of theplate 34 by means of a threaded connection, which has a conical tip at his end facing the driving end of therod 10, in order to cooperate with a corresponding seat formed in a position adjacent to thehole 31, for allowing the section of the hole to be changed as a result of the control of such a spindle by means of a tool which can be driven from the outside of thecylinder 5.
Claims (10)
1. A device for dampening the oscillation of the arm of a handling equipment of the swingable lever type, which equipment (1) comprises a driving double acting cylinder (5) having a chamber (18) in which a main piston (15) is sealingly mounted, which is slidable as a result of the selective delivery of fluid under pressure at opposite zones of the chamber (18) of the cylinder (5), the main piston (15) being connected to a rod (10) having a driving end (10 a) which projects from the cylinder (5) and is associated with said arm (7),
characterised in that an axial cavity (27) separated from the chamber (18) of the cylinder (5) and containing a service fluid is formed inside the rod (10), a stem (30) rigidly connected with the cylinder (5) and provided with orifice means (31, 31 a) for the service fluid being sealingly and slidably mounted in such a cavity (27), so that the movement of the rod (10) with respect to the stem (30) is slowed down as a consequence of the flowing of the service fluid through the orifice means (31, 31 a), if the sliding speed of the main piston (15) inside the cylinder (5) exceeds a threshold speed set by the cross-section of the orifice means (31, 31 a).
2. A device according to claim 1 , characterised in that the stem (30) has an enlarged head (29) in proximity of which orifice means (31, 31 a) for the service fluid are arranged.
3. A device according to claim 2 , characterised in that a seal (32) is interposed between the enlarged head (29) of the stem (30) and the wall delimiting the axial cavity (27) of the rod (30).
4. A device according to anyone of claims 1 to 3 , characterised in that the stem (30) has an end fixed to a support plate (34) anchored to the bottom of the cylinder (5).
5. A device according to claim 1 , characterised in that the axial cavity (27) of the rod (30) has a variable longitudinal extension for allowing to compensate the variation of the extension of the stem (30) received inside the cavity (27).
6. A device according to claim 5 , characterised in that a floating auxiliary piston (38) is arranged in proximity of the end of the axial cavity (27) opposed to the stem (30).
7. A device according to claim 6 , characterised in that the floating auxiliary piston (38) is associated with guide means (42, 46) for its axial movement.
8. A device according to claim 7 , characterised in that the guide means of the axial movement of the auxiliary piston (38) comprise a pin (42) one end of which is connected to the auxiliary piston (38), while the opposite end is slidably mounted in a corresponding seat (46) formed in proximity of the driving end (10 a) of the rod (10).
9. A device according to claim 8 , characterised in that said seat (46) communicates with the outer environment with respect to the cylinder (5) by means of a vent hole (48).
10. A device according to claim 1 , characterised in that the cross-section of the orifice means (31, 31 a) is variable as a result of the movement of an adjustment member which can be controlled from the outside of the equipment (1).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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ITTO2002A000504 | 2002-06-14 | ||
IT2002TO000504A ITTO20020504A1 (en) | 2002-06-14 | 2002-06-14 | ARM SWING DAMPING DEVICE OF A SWING LEVER TYPE HANDLING EQUIPMENT |
Publications (1)
Publication Number | Publication Date |
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US20040065194A1 true US20040065194A1 (en) | 2004-04-08 |
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Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/460,250 Abandoned US20040065194A1 (en) | 2002-06-14 | 2003-06-13 | Device for dampening the oscillation of the arm of a handling equipment of the swingable lever type |
Country Status (3)
Country | Link |
---|---|
US (1) | US20040065194A1 (en) |
EP (1) | EP1371857A1 (en) |
IT (1) | ITTO20020504A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050217477A1 (en) * | 2004-04-03 | 2005-10-06 | Zf Friedrichshafen Ag | Piston-cylinder unit |
US20130205993A1 (en) * | 2012-02-13 | 2013-08-15 | Kenneth J. Stoddard | Adaptive hydraulic cylinder with floating seal interface |
CN116175717A (en) * | 2022-11-29 | 2023-05-30 | 苏州艾维科斯园林设备有限公司 | Bidirectional rapid energy-saving efficient hydraulic log splitter |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7565859B2 (en) | 2006-04-25 | 2009-07-28 | Smc Corporation Of America | Power clamp with kinetic energy control |
WO2012007020A1 (en) * | 2010-07-14 | 2012-01-19 | Tünkers Maschinenbau Gmbh | Pivoting device for the pivoting movement of materials, in particular for use in body construction in the motor vehicle industry |
SE536053C2 (en) * | 2011-06-17 | 2013-04-16 | Asa Suspension Ab | Device for damping in a piston cylinder device |
SE538615C2 (en) * | 2014-06-09 | 2016-10-04 | Thordab Ind Innovation Ab | Hydraulcylinder |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2624318A (en) * | 1946-06-24 | 1953-01-06 | Rheem Mfg Co | Pneumatic servomotor |
US3313214A (en) * | 1964-06-16 | 1967-04-11 | Sandex Inc | Power feed with liquid check |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2920423A1 (en) * | 1979-05-19 | 1980-11-27 | Stabilus Gmbh | COMPRESSED AIR CYLINDER WITH LOCKING DEVICE |
DE3017403A1 (en) * | 1980-05-07 | 1981-11-12 | Stabilus Gmbh, 5400 Koblenz | HYDROPNEUMATIC FEED CYLINDER |
-
2002
- 2002-06-14 IT IT2002TO000504A patent/ITTO20020504A1/en unknown
-
2003
- 2003-06-12 EP EP03013186A patent/EP1371857A1/en not_active Withdrawn
- 2003-06-13 US US10/460,250 patent/US20040065194A1/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2624318A (en) * | 1946-06-24 | 1953-01-06 | Rheem Mfg Co | Pneumatic servomotor |
US3313214A (en) * | 1964-06-16 | 1967-04-11 | Sandex Inc | Power feed with liquid check |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050217477A1 (en) * | 2004-04-03 | 2005-10-06 | Zf Friedrichshafen Ag | Piston-cylinder unit |
US7197975B2 (en) * | 2004-04-03 | 2007-04-03 | Zf Friedrichshafen Ag | Piston-cylinder unit |
US20130205993A1 (en) * | 2012-02-13 | 2013-08-15 | Kenneth J. Stoddard | Adaptive hydraulic cylinder with floating seal interface |
US9435359B2 (en) * | 2012-02-13 | 2016-09-06 | Schlumberger Technology Corporation | Adaptive hydraulic cylinder with floating seal interface |
CN116175717A (en) * | 2022-11-29 | 2023-05-30 | 苏州艾维科斯园林设备有限公司 | Bidirectional rapid energy-saving efficient hydraulic log splitter |
Also Published As
Publication number | Publication date |
---|---|
EP1371857A1 (en) | 2003-12-17 |
ITTO20020504A0 (en) | 2002-06-14 |
ITTO20020504A1 (en) | 2003-12-15 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: VEP AUTOMATION S.R.L., ITALY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:VARETTO, ENER;PICCOLO, LIO;REEL/FRAME:014663/0263 Effective date: 20030730 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |