BERTONI, Stefano (Via Pagani 133/3, Modena, I-41124, IT)
| Claims. 1. A coil (11) for an electromechanical actuator, comprising: a spool (16) developing about an axis (X); and a winding (17) defined by a conducting wire wound about the spool (16) and having two terminals which are electrically connectable to a respective connector (19) for electrically supplying the winding (17); characterised in that the spool (16) exhibits a first connecting portion (24) engageable to a corresponding second connecting portion (25) of the connector (19) by means of reciprocal insertion, the first connecting portion (24) exhibiting at least two first electrical connections (24a, 24b) separately connected to the terminals of the conducting wire and arranged in a predetermined arrangement on the first connecting portion (24). 2. The coil of claim 1, characterised in that the first connecting portion (24) is a male connector and is insertable in the second connecting portion (25), which is a female connector, of the connector (19). 3. The coil of claim 1 or 2, characterised in that the spool (16) exhibits an annular conformation, and in that the first connecting portion (24) is arranged on an annular frontal surface of the spool (16) and develops along a parallel direction to the axis (X). 4. The coil of any one of the preceding claims, characterised in that the first connecting portion (24) is solidly constrained to the spool (16) and is preformed together with the spool (16). 5. A connector (19), usable with a coil (11) of any one of the preceding claims, characterised in that it comprises a first body (20) exhibiting the second connecting portion (25) on an external surface thereof; the second connecting portion (25) exhibiting at least two second electrical connections (25a, 25b) being connectable to an electricity grid and being arranged in a predetermined arrangement on the second connecting portion (25) in order to electrically connect to the at least two first electrical connections (24a, 24b) of the coil (11). 6. The connector of claim 5, characterised in that the first body (22) comprises two second connecting portions (24) which develop along a same direction and are arranged on an external surface of the first body (22) in reciprocally opposite positions. 7. The connector of claim 5 or 6, characterised in that it comprises a second body (22), solidly constrained to the first body (20) and side-by-side therewith along a prevalent direction of development (A) of the connector (19); the second body (22) having a dimension which is larger than a dimension of the first body (20) when measured transversally of the prevalent direction of development (A). 8. The connector of claim 7, characterised in that the second body (22) exhibits at least two electrical terminals (500, 600; 700; 800) which are connectable to the electricity grid and which are connected to the electrical connections (25a, 25b) of the connector (19) in accordance with a predefined electrical diagram; the electrical terminals (500, 600; 700; 800) preferably being connected to the electrical connections (25a,25b) of the connector (19) by platelets (26, 27, 28) made of a conductor material sunk into the connector (19). 9. The connector of claims 6 and 8, characterised in that one of the second connecting portions (25) exhibits a first and a second electrical connection (100, 200) and in that the other second electrical connection (25) exhibits a third and a fourth electrical connection (300, 400), the second body (22) comprising four electrical terminals (500, 600; 700; 800), a first (500) of the terminals being connected to the first and third electrical connection (100, 300), a second (600) of the electrical terminals being connected to the second electrical connection (200), a third (700) of the electrical terminals being connected to the fourth electrical connection (400), preferably the fourth electrical terminal (800) being electrically connected to an earth. 10. The connector of claim 7, characterised in that it comprises an intermediate portion (21), interposed between the first body (20) and the second body (22) and defining a housing seating for a seal (23), preferably an O-ring. 11. An electro-mechanical actuator (1), characterised in that it comprises: an external casing (2) having a through-cavity (3) which is accessible from two opposite front sides of the external casing (2) and further having a lateral hole (9) for enabling a lateral access to the through-cavity (3); a connector (19) as in any one of claims from 5 to 10, the connector (19) being inserted in the lateral hole (9) such that the first body (20) is arranged in the cavity (3); a pair of coils (11) as in any one of claims from 1 to 4 and inserted in the through-cavity (3), the first connecting portion (24) of each coil (11) being connected by reciprocal insertion with the respective second connecting portion (25) of the connector (19) such as to establish an electrical continuity between the winding (17) of the coils (11) and the electrical terminals (500, 600; 700; 800) of the connector (19). 12. The actuator of claim 11, characterised in that the connector (19) is inserted in the lateral hole (9) such that the intermediate portion (21) is arranged at the lateral hole (9), the actuator (1) comprising a seal ring (23), preferably an O-ring, interposed between the connector (19) and the external casing (2) and defining a seal at the lateral hole (9) of the external casing (2). |
Technical Field
The invention relates to a coil for an electromechanical actuator of the linear type, i.e. a type activated by means of an electrical excitation and having a linear output movement via an actuation organ. Preferably, though not exclusively, the present invention relates to a coil for an electromechanical actuator used for activating brake shoes, and in particular brake shoes of hoist winches. Background Art
Linear electromechanical actuators commonly used for activating brake shoes comprise an external casing having two opposite coils in which respective magnetic nuclei are slidably inserted. The two nuclei are axially aligned and are thrust in a reciprocally-distancing direction by means of a magnetic action exerted by the excitation of the respective coils. The distancing of the nuclei determines the mechanical activation of the actuator and, thus, the activation of the brake shoes. Each of the two coils comprises a spool on which a coil is wound, the two ends of which emerge from the coil and which are connected to an electrical supply grid.
An actuator of the above type exhibits an important drawback, concerning the connection of the actuator to the electrical supply. During assembly of the actuator an opening has to be made In the external casing; the four heads of the two coils have to be made to pass through this hole. The heads must then be manually connected to the supply lines of the electricity grid, by application of traditional plastic connectors commonly used in any electrical plant, or alternatively by welding.
The manual connection is not only laborious and necessary each time the actuator is to be replaced, but also generally brings with it the risk of breaking the insulation cladding of the conducting wires during their manual connection. This can lead to the generation of electrical discharge between the wires, which either damage or even break the connection, with a consequence that the actuator is no longer usable and has to be replaced.
Further, the opening made in the casing becomes a preferential passage for dust, dirt or moisture which can reach as far as the coils, damaging the functioning of the actuator or reducing its working life.
In this context, the technical aim at the base of the present invention is to provide an electromechanical actuator which obviates the drawbacks of the prior art. In particular an aim of the present invention is to make available an electromechanical actuator which exhibits great simplicity of assembly.
A further aim of the present invention is to provide an electromechanical actuator which exhibits great simplicity of installation.
A still further aim of the present invention is to make available an electromechanical actuator which exhibits great reliability and a long working life.
The specified technical aim and objectives are substantially attained by a coil and a connector comprising the technical characteristics respectively set out in claims 1 and 5 and/or in one or more claims depending thereon, and by an electromechanical actuator having the technical characteristics set out in claim 11 or 12.
Disclosure of Invention Further characteristics and advantages of the present invention will better emerge from the following description, which is not limiting, of a preferred though not exclusive embodiment of a mechanical actuator, as illustrated in the accompanying figures of the drawings, in which: figure 1 is a perspective view of an electromechanical actuator of the present invention; figure 2 is an exploded perspective view of the actuator of figure 1 ; figure 3 is a section view of the actuator of figure 1 along line III-III of figure 4; figure 4 is a section view of the actuator of figure 1 along line rV-IV of figure 3; figure 5 is a perspective view of a portion of the actuator of figure 1, with some parts removed better to evidence others; figure 6 is an exploded perspective view of the portion of the actuator of figure 5; figure 7 is an exploded perspective view of a detail of the actuator of figure i; figure 8 is a perspective view of the detail of figure 7 with some parts removed better to evidence others. In the figures, 1 denotes in its entirety a coil for an electromechanical coil of the present invention. In particular, the electromechanical actuator 1 of the invention is of the linear type.
The actuator 1 comprises a substantially circular-section cylindrical external casing 2, internally exhibiting a through-cavity 3 and closed at ends thereof by a pair of covers 4 anchored by fastening screws 5.
The covers 4 exhibit a central hole through which pushers 6 emerge which actuate the linear actuator 1 and run in opposite directions along a common axis X, about which the whole actuator develops. In the preferred application of the actuator 1, the pushers 6 are destined to move respective brake shoes (not illustrated) of a hoist winch, for example of a lift. The operating modes will be discussed in the following.
The actuator 1 further comprises a manual activating lever 7, arranged on the external cylindrical surface of the casing 2 in a substantially equidistant position from the two covers 4. Connecting means 8 are comprised on the external casing 2 in an angularly spaced position of a right angle with respect to the lever 7, which connecting means 8 are for electrically connecting the actuator 1 to an electricity grid. The connecting means 8 are also arranged in a substantially equidistant position from the two covers 4. In greater detail, as can be seen in figure 2, the external casing 2 exhibits a first through-hole 9, positioned at the connecting means 8, and a second hole 10, positioned at the lever 7. Both the holes 9, 10 are through-holes and enable access to the cavity 3 from the outside the external casing 2. Two coils 11, two translators 2 and a contrast spring 13 are housed internally of the casing 2.
In figures 2 and 3, the coils 11 have an external diameter which is substantially equal to the internal diameter of the casing 2, and are inserted therein up to striking against a respective striker spring 14 (figure 3) which is blocked by an internal step 15 in the casing 2. The coils 11 are blocked in position by the covers of the casing 2.
In the present invention, the term coil is taken to mean the totality of an annular rigid spool 16, preferably made of an insulating plastic material, and a conductive wire wound on the spool 16 to define a winding 17. The coils 11 are therefore inserted in the cavity 3 such as to be coaxial to one another and coaxial to the axis X.
A respective translator 12 is slidably inserted internally of each spool 16, which at an end thereof bears one of the pushers 6. The translator 12 is supported on one side by means of the pusher 6, inserted in the cover 4, and on the other side it is slidably supported by the respective striker ring 14. The actuator 1 has a substantially specular configuration with respect to a plane passing through the holes 9, 10 and consequently the translators 12 are mounted in a reciprocally opposite position. The translators 12 are pushed in a reciprocally distancing direction such as to maintain the pushers 6 in a position in which they have exited from the covers 4. A space is determined between the two translators 12, in which space a manoeuvring organ 18 of the lever 7 is active. The manoeuvring organ 18 exhibits an elongate protuberance which is mobile between a rest position (illustrated in figure 4), in which it is arranged in a perpendicular plane to the axis X, and an operating position in which it is arranged in a plane passing through the axis X to push the two translators 12 away from each other and therefore to activate the two pushers 6. The manoeuvring organ 18 therefore has a maximum dimension which substantially corresponds to the size of the space comprised between the two translators 12 when the translators are in a reciprocally distanced position. The passage from the rest position to the operating position of the manoeuvring organ 18 is done by rotation about an axis which is perpendicular to the axis X and incident to the axis X. This rotation is impressed by a rotation movement of the lever 7.
Figure 1 and figure 3 show the connecting means 8 in detail. The connecting means 8 comprise a connector 19 having a development direction A that coincides with the connector insertion direction in the first hole 9. Along the development direction A, the connector 19 exhibits a first body 20, an intermediate portion 21 and a second body 22 which are solidly associated and define a single rigid body. The first body 20 exhibits a circular-section cylindrical shape which is substantially such as to be inserted into the first hole 9. The intermediate portion 21 defines a housing seating of a seal ring 23, preferably an O-ring, or gasket, which is operative interposed between the connector 19 and the casing 2 to define a seal between the connector 19 and the casing 2 at the first hole 9.
The second body 22 exhibits a dimension, measured transversally to the prevalent development direction A of the connector 19, which is greater with respect to the first body 20 and the first hole 9 such as to define a stop against the external surface of the casing 2 and allow fastening of the connector 19 to the casing 2.
The first body 20 of the connector 19 is advantageously electrically couplable to the two coils 11 automatically, i.e. by predefined connecting means in order to facilitate the assembly of the actuator 1. With particular reference to figures 5 and 6, each coil 11 exhibits a first connecting portion 24 fixed to the spool 16, while the first body 20 of the connector 19 exhibits two second connecting portions 25, each of which is stably couplable to the first connecting portion 24 of a coil 11 in order to determine an electrical continuity between the coil 11 and the connector 19. The coupling between the first and the respective second connecting portion 24, 25 is preferably done by reciprocal insertion, and the insertion is done at the moment of insertion of the actuator 1 insertion. In more detail, the first connecting portion 24 develops distancingly from an annular frontal surface of the spool 16, preferably along a parallel direction to the axis X. More preferably, the first connecting portion 24 is male, and exhibits at least two separate electrical connections 24a, 24b, each of which is electrically connected to an end of the wire defining the winding 17. The first connecting portion 24 thus takes on the form of a plug.
The first connecting portion 24 is rigidly connected to the spool 16, and is preferably preformed with the spool 16, i.e. it is realised during the manufacturing process with which the spool 16 is made.
Further, the first connecting portion 24 (not illustrated in detail) preferably comprises: a first part made in a single piece with the spool and from which project two blades made from a conductor material defining the above-mentioned electrical connections 24a, 24b; and a second part made of an insulating material, preferably plastic, applied to the first part and having a pair of slits for receiving the blades sunk into the first part and for enabling the blades to enter into contact with corresponding blades in the respective second connecting portion 25 of the connector 19. Further, the second part is destined to couple by means of reciprocal insertion with the respective second connecting portion 25 of the connector 19.
Each second connecting portion 25 is arranged on the external cylindrical surface of the first body 20 of the connector 19 and preferably develops along a direction which is parallel to the axis X in order to fit, by reciprocal insertion, with the first connecting portion 24 of one of the coils 11 following insertion of the coil 11 into the cavity 3 of the actuator 1. More preferably, each second connecting portion 25 is female and exhibits at least two separate electrical connections connectable to one of the electrical connections 24a, 24b of the coil 11.
The two second connecting portions 25 thus take on a cavity configuration, into which a plug-shaped first connecting portion 24 of the coil 24 is insertable. Further, the two connecting portions 25 are arranged on the first body 20 in a diametrically opposite position and develop along a same parallel direction to the axis X. In other words, the two second connecting portions 25 are reciprocally aligned. To enable insertion of the first connecting portions 24 in the first body 20 of the connector 19, the striker rings 14 exhibit special through-openings 31 which develop parallel to the axis X, as shown in figure 3. The electrical connections 24a, 24b, 25a, 25b are arranged on the respective first or second connecting portions 24, 25 in a predetermined arrangement, destined to determine an automatic and correct connection of the electrical connections 24a, 24b, 25a, 25b during the stage of assembly of the actuator 1. In the first embodiment illustrated in the figures, the electrical connections 24a, 24b, 25a, 25b are preferably blades made of a conductor material sunk into the connector 19, which is preferably made of an insulating plastic material.
Figure 8 shows the arrangement of the blades internally of the connector 19. The illustrated configuration is adopted for connection to a direct- current supply grid, comprising two supply cables, respectively defining electric poles, and a connecting cable to an earthing device. For the sake of simplicity, the four electrical connections of the connector 19 are denoted, in figure 8, with reference numbers 100, 200, 300, 400. The first two electrical connections 100, 200 are destined to be connected to a coil 11, while the other two electrical connections 300, 400 are destined to be connected to the other coil 11. hi detail: a first blade 26 exhibits two ends respectively defining the first 100 and the third 300 of the electrical connections, and a further end defining a first electrical terminal 500 connectable to a respective pole of the electricity grid in direct current; a second blade 27 exhibits an end defining the second electrical connection 200, and a further end defining a second electrical terminal 600 connectable to a respective pole of the electrical current in direct current; a third blade 28 exhibits an end defining the fourth electrical connection 400, and a further end defining a third electrical terminal 700 connectable to a respective pole of the electricity grid. The connections of the blades 26, 27, 28 to the two poles of an electricity grid in direct current will be described herein below.
A fourth blade 29 exhibits an end defining a fourth electrical terminal 800, and a further end connectable to an earthing circuit (not illustrated), for example realised with a metal screw V fastening the connector 19 to the casing 2 of the actuator 1. The fourth electrical terminal 800 is connectable to the neutral wire of the electricity grid.
Thus precise predefined electrical connections are made via the blades 26, 27, 28, 29 between the electrical terminals 500,600, 700, 800 and the respective electrical connections 100, 200, 300, 400 (and the earthing circuit). The electric terminals 500, 600, 700, 800 emerge from the connector 19 at the second body 22 and are connectable in traditional ways to the two poles of the electric grid. In particular, in a first connection mode, the second and the third electric terminals 600, 700 are electrically connected to one another, for example by a bridge, and are thus connected to a first pole of an electricity grid in alternating current, while the first electric terminal 500 is connected to the other pole of the grid in alternating current. The fourth electrical terminal 800, on the other hand, is connected to an earthing circuit. With this connection, a flow of symmetrical electric current flows into the two coils 11 , which current generates respective opposite magnetic fields in the coils 11 to move the translators 12 in an opposite direction to one another. In a second mode of connection, the second and the third electrical terminals 600, 700 are respectively connected to the first and the second poles of the electricity grid, while the second electrical terminal 500 is not connected to the electricity grid. Thus a series connection of the two coils 11 is obtained. The direct connection between the two ends of the first blade 26 defining the first 100 and the third 300 electrical connections enables the series connection of the two coils 11.
A covering element 30 is applicable to the second body 22 in order to protect the electrical terminals 500, 600, 700, 800 and the free heads of the wires (not illustrated) constituting the two poles of the electricity grid. In an assembly procedure of the actuator 1, firstly the striker rings 14 are inserted, with the connector 19. In particular, the connector 19 is inserted such that the first body 20 is arranged internally of the cavity 3 while the intermediate portion 21 with the seal ring 23 is arranged about the first hole 9. Thereafter, the coils 11 are inserted such that the respective first connecting portions 24 pass through the through-openings 31 of the striker rings 14 and insert in the corresponding second connecting portions 25 of the connector. At this point the translators 12 can be inserted and the coils 11 packed, fastening them into position by the application of the covers 4. The application of the lever 7 can occur at any time of the above-described assembly stages.
With the functioning of the actuator 1 in a braking plant for winches, the contrast spring 13 maintains the translators 12 distanced and maintains the pushers 5 in the projecting position from the covers 4. A brake shoe acts on each pusher 5, which brake shoe 5, on the action of springs, tends to keep the pusher 5 towards the inside of the actuator 1 , determining a braking action on the winch.
During the functioning of the winch, there is a passage of current through the coils 11 and this determines a magnetic force on the translators 12 which overcomes the push of the shoes, forcing them to open and unblock the braking action on the winch. In operating conditions, therefore, the translators 12 are maintained distanced from one another by the magnetic action. hi a case of malfunctioning or interruption of electricity supply, the coils 11 are not excited and the brake shoes, by the action of the respective springs, return the pushers into a neared position, blocking the winch. In this situation, it is impossible to unblock the winch since, in the absence of current, there are no means for overcoming the force of the brake shoes. The lever becomes important in this situation, as it can be rotated manually up to opening the translators, thus overcoming the force of the brake shoes and unblocking the winch.
The present invention attains the set aims, and overcomes the drawbacks noted in the prior art. The special conformation of the first and second connecting portions, respectively of the coils and the connector, enable rapid assembly of the actuator without there being any need to connect the heads of the coil windings manually. This also eliminates any need for manual connection of the wires and thus also removes any risk of damage to the heads of the wires and therefore any damage to the actuator itself. This is also made possible by the presence of the blades sunk into the plastic material of the connector, which does not require the manual connection of the wire heads. Further, the plug-socket insertion of the connecting portions enables a simple and practical connection of the connector to the coils. Further, the conformation of the connector with the mounting of the seal ring enables a seal to be realised between the internal cavity of the casing and the outside of the actuator, with an evident increase in the actuator's working life.
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