Patent Description:
As is known, an RFID (Radio-Frequency IDentification) system comprises at least one RFID tag (or transponder), a reader for reading and/or writing data, and a data management information system for transferring the data to and from the reader. The identification and the exchange of information between RFID tag and reader occurs in radiofrequency.

The RFID tag comprises a microchip containing data in a memory, at least one antenna, and a physical support, called substrate, for keeping the microchip and the at least one antenna together.

The antenna receives a signal from the reader, said signal being transformed by means of the electromagnetic induction principle into electric energy, which can feed the microchip. By means of the antenna, the microchip communicates with the reader, which can read and/or write data on the RFID tag.

The antenna, made of a metal wire, typically has a shaped curvilinear shape. Therefore, an antenna with a relatively long length can be deposited on a substrate, for example adhesive tape, having a relatively reduced area.

<CIT> illustrates a machine for forming RFID antennas wherein the wire is wound around a series of pegs carried by a forming device rotating in reciprocating motion.

The machine of <CIT> comprises a support structure provided with a support for an RFID substrate, and a plurality of forming pegs having vertical axes and arranged above said support so as to define a predetermined path for a wire configured to form the RFID antenna; a wire feeding system comprising a wire guide element and a handling assembly, configured to move the wire guide element along a horizontal axis so as to wind the wire at least partially around the forming pegs and define said path; a pair of grippers arranged at the ends of said path and operable to assume a closed position, in which the wire is blocked, and an open position, in which the wire is released; and a movable structure carried by the support structure and provided with a thrust element movable vertically between an upper position in which said thrust element allows the wire to be wound around the pegs and a lower position in which said thrust element deposits the formed antenna on the substrate.

<CIT> illustrates a method and an apparatus for making an RFID device provided with an antenna made of an electrically conductive wire.

To manufacture a machine which allows obtaining an antenna with a desired shape and depositing it on a substrate is a complex problem, as it is necessary to coordinate different operations, some of which must be carried out simultaneously and require an accurate synchronization. Furthermore, the use of a rotating forming device strongly limits the obtainable geometries of the antenna and has problems of dynamic nature.

The object of the present invention is to manufacture a machine for forming RFID antennas, which allows overcoming the aforementioned problems.

The aforementioned object is achieved by a machine for forming RFID antennas as claimed in claim <NUM>.

In order to better understand the present invention, a preferred embodiment is described in the following, by way of non-limiting example and with reference to the accompanying drawings, wherein:.

With reference to <FIG>, reference numeral <NUM> indicates a machine for forming RFID antennas according to the present invention.

The machine <NUM> comprises a horizontal base <NUM>, a fixed structure <NUM> which extends vertically upward from the base <NUM>, a movable structure <NUM> carried by the fixed structure <NUM>, and a wire feeding system <NUM> for forming the antennas.

The base <NUM> is substantially a parallelepiped having main dimensions along two horizontal axes X and Y, orthogonal with respect to each other, and reduced height along a vertical axis Z. Preferably, the base <NUM> has, in a central portion thereof, a through cavity <NUM> with a substantially parallelepiped shape having main dimensions parallel to the axes X and Y.

The fixed structure <NUM> comprises a vertical wall <NUM>, parallel to the axis Y and extending upward in the proximity of a corner of the base <NUM>, a lower plane <NUM> and an upper plane <NUM> which are horizontal and extend cantilevered from the vertical wall <NUM> toward a central portion of the base <NUM>. The lower plane <NUM> and the upper plane <NUM> substantially have the same dimension along the axis X, whereas the dimension along the axis Y of the lower plane <NUM> is greater than that of the upper plane <NUM>, which is centred vertically with respect to the lower plane <NUM>.

The lower plane <NUM> is supported by the base <NUM> by means of vertical supports <NUM> extending along respective sides of the lower plane <NUM> parallel to the axis Y. The lower plane <NUM> has, in a central portion thereof, a rectangular through cavity <NUM> having sides parallel to the axes X and Y, and centred vertically with respect to the cavity <NUM> of the base <NUM>.

The cavity <NUM> houses with lateral clearance a horizontal plate <NUM> comprising an upper face <NUM> configured to slidingly support an adhesive tape (not illustrated), pitch-fed parallel to the axis X and defining a substrate for the antennas. The vertical position of the plate <NUM> can be adjusted by means of a screw system <NUM>.

The upper plane <NUM> comprises an upper face <NUM> and a lower face <NUM>. The fixed structure <NUM> comprises an upper support <NUM> coupled at the top to the upper face <NUM>, and a lower support <NUM> coupled at the bottom to the lower face <NUM>.

The upper support <NUM> of the fixed structure <NUM> substantially has an "upside down U" shape and comprises two vertical walls <NUM>, parallel with respect to each other and to the axis Y, and an upper horizontal wall <NUM> joining respective upper sides of the walls <NUM>, and defining a compartment <NUM> with them.

The wall <NUM> carries a vertical actuator <NUM> of axis A, extending below the wall <NUM> and inside the compartment <NUM>.

The vertical actuator <NUM> is preferably a linear actuator comprising a fixed part <NUM>, coupled at the top to the wall <NUM> of the upper support <NUM>, and a movable part <NUM>, comprising a shaft <NUM> of axis A and two movable guides <NUM> arranged on opposite sides of the shaft <NUM> along a plane parallel to the axis Y. The shaft <NUM> and the movable guides <NUM> are fixed at the bottom to a horizontal terminal plate <NUM>. The movable guides <NUM> slidingly engage respective holes of the fixed part <NUM>, with the aim to prevent a rotation of the shaft <NUM> and of the terminal plate <NUM> around the axis A. The terminal plate <NUM> of the vertical actuator <NUM> is coupled to the movable structure <NUM> of the machine <NUM>, specifically described in the following.

The lower support <NUM> of the fixed structure <NUM> substantially has a "U" shape and comprises two vertical headpieces <NUM>, extending at the bottom from the lower face <NUM> of the lower support <NUM>, and a horizontal plate <NUM> carried by the headpieces <NUM> by means of respective brackets <NUM>.

The headpieces <NUM>, equidistant with respect to the axis A, are substantially parallelepipeds having respective inner faces <NUM> parallel to the axis Y and facing the axis A.

The brackets <NUM> substantially have an "upside down T" shape and each one comprises a vertical core <NUM> fixed to the inner face <NUM> of the respective headpiece <NUM> and a horizontal wing <NUM> on which the plate <NUM> rests.

The fixed structure <NUM> further comprises four screws <NUM> whose vertical axes are arranged at the vertexes of a horizontal rectangle having centre on the axis A.

Each screw <NUM> comprises a head <NUM> and a cylindrical stem <NUM>. The distance between the stems <NUM> of the screws <NUM> facing each other in a direction parallel to the axis Y is substantially equal to the width of the plate <NUM> in such direction, so that the heads <NUM> of the screws <NUM> partially rest on the opposite edges of the plate <NUM> and the stems <NUM> rest laterally against such edges.

The fixed structure <NUM> further comprises a terminal structure <NUM> with a substantially parallelepiped shape at reduced height, provided with four upper vertical projections <NUM>, in the proximity of the vertexes thereof, in which the stems <NUM> of the screws <NUM> are screwed.

The terminal structure <NUM> supports a central horizontal plate <NUM> from a lower face <NUM> of which a plurality of vertical pegs <NUM> extends at the bottom, passing through respective through-holes of the terminal structure <NUM>.

The morphology and arrangement of the pegs <NUM> depend on the desired shape of the antenna. In particular, the pegs <NUM> are vertical cylinders having equal height but possibly a different diameter with respect to each other. The diameter and the positioning of the pegs <NUM> determine respectively the curvature and the position of the loops present in the curvilinear shape of the antenna.

In the illustrated example, the pegs <NUM> are seven and have symmetrical morphology and arrangement with respect to a vertical plane passing through the axis A and parallel to the axis X.

The pegs <NUM> are delimited at the bottom by base surfaces <NUM> facing and parallel to the upper face <NUM> of the plate <NUM>, and vertically equidistant with respect to it.

It is worth mentioning that the pegs <NUM> are fixed and belong to the fixed structure <NUM> of the machine <NUM>.

The movable structure <NUM> of the machine <NUM> comprises a thrust element <NUM> suspended from the terminal plate <NUM> of the vertical actuator <NUM> by means of cylindrical shafts <NUM>, with vertical axis, mounted passing and slidable through respective holes of the upper plane <NUM>.

The thrust element <NUM>, vertically movable, comprises an upper structure <NUM> carried by the shafts <NUM>, an intermediate structure <NUM> carried by the upper structure <NUM> and arranged below it, and a lower structure <NUM> carried by the intermediate structure <NUM> and arranged below it.

The upper structure <NUM> of the thrust element <NUM> comprises a horizontal plate <NUM> arranged above the plate <NUM> of the fixed structure <NUM>, and four legs <NUM> extending downward in the proximity of the corners of the plate <NUM>. The plate <NUM> is fixed at the top to the shafts <NUM>. The legs <NUM> are fixed to the intermediate structure <NUM> and delimit with it and with the plate <NUM> a compartment <NUM> that houses the plate <NUM> and the heads <NUM> of the screws <NUM> of the fixed structure <NUM>. Therefore, the upper structure <NUM> is movable downward until the plate <NUM> stops against the heads <NUM> of the screws <NUM>.

The intermediate structure <NUM> of the thrust element <NUM> substantially has an "upside down U" shape and comprises two vertical walls <NUM>, parallel to each other and to the axis X, and an upper horizontal wall <NUM> integrally connected to the walls <NUM> along sides thereof parallel to the axis X and defining a compartment <NUM> with them.

The walls <NUM> of the intermediate structure <NUM>, equidistant with respect to the axis A, carry respective grippers <NUM>.

For convenience, the duplicated components, i.e. present both on the left and on the right (according to the front view of <FIG> of the machine <NUM>) with respect to a vertical plane passing through the axis A and parallel to the axis X, are indicated with the suffix "a" and "b" after the reference numeral when it is necessary to make a distinction between the same. If the suffix is not used, the description refers without distinction to one or the other of the duplicated components.

Each gripper <NUM> comprises a fixed jaw <NUM> fixed to the wall <NUM> and a movable jaw <NUM> hinged to the fixed jaw <NUM> by means of a pin <NUM> having axis parallel to the axis Y.

Each fixed jaw <NUM> is fixed to the respective wall <NUM> and is substantially a vertical plate provided at the bottom with a through-hole for the pin <NUM> and with a beak <NUM> having a knurled gripping surface <NUM> extending along a plane parallel to the axis X and inclined downward and outward with respect to the fixed part <NUM> of the machine <NUM>. Each fixed jaw <NUM> carries a blade <NUM>, interposed between it and the fixed structure <NUM>, comprising a surface inclined parallel to the gripping surface <NUM>.

Each movable jaw <NUM> is coupled, in a rotatable manner, to the respective fixed jaw <NUM> on the opposite side with respect to the respective wall <NUM> and comprises an upper portion <NUM> and a lower portion <NUM>.

The upper portion <NUM> of the movable jaw <NUM> substantially has a "T" shape and comprises a substantially vertical stem <NUM>, parallel to the fixed jaw <NUM>, and a crosspiece <NUM> extending cantilevered from the stem <NUM> in opposite direction with respect to the fixed part <NUM> and delimited at the bottom by a first lower face <NUM> and a second lower face <NUM> inclined and incident with respect to each other so as to substantially form a "V"-shaped profile.

The movable jaws 86a, 86b are identical to each other and are mounted rotated by <NUM> degrees around the axis Z with respect to each other. Therefore, the first lower face 95a of the movable jaw 86a is arranged toward the wall <NUM>, whereas the first lower face 95b of the movable jaw 86b is arranged on the opposite side with respect to the wall <NUM>. Similarly, the second lower face 96a of the movable jaw 86a is arranged on the opposite side with respect to the wall <NUM>, whereas the second lower face 96b of the movable jaw 86b is arranged toward the wall <NUM>.

The lower portion <NUM> of each movable jaw <NUM> is provided at the bottom with a through-hole for the pin <NUM> and with a beak <NUM>, extending laterally cantilevered, having a knurled gripping surface <NUM> extending parallel to the gripping surface <NUM> of the fixed jaw <NUM> and facing it. Each movable jaw <NUM> carries a blade <NUM>, coupled to the beak <NUM> and interposed between it and the fixed structure <NUM>, comprising a surface inclined parallel to the gripping surface <NUM>.

The movable jaws <NUM> are movable between an open position (<FIG> and <FIG>), in which the beak <NUM> is deviated from the beak <NUM> and the stem <NUM> is inclined, and a closed position (<FIG> and <FIG>), in which the gripping surfaces <NUM> and <NUM> of the beaks <NUM> and <NUM> substantially fit together for blocking the wire and the stem <NUM> is vertical.

The pins 87a, 87b of the grippers 84a, 84b are moved with respect to each other in the direction X so that the beaks 88a, 101a are aligned with the beaks 88b, 101b in a direction parallel to the axis Y in the closed position of the respective grippers 84a, 84b.

The wall <NUM> of the intermediate structure <NUM> has four through-holes provided with respective brushings <NUM> slidable on respective stems <NUM> of the fixed structure <NUM>.

The lower structure <NUM> of the thrust element <NUM> is substantially a horizontal plate arranged below the terminal structure <NUM> of the fixed structure <NUM> and comprising an upper face <NUM> and a lower face <NUM>. The upper face <NUM> has at the vertexes thereof respective horizontal projections coupled at the top to the intermediate structure <NUM>. The lower face <NUM>, parallel to the upper face <NUM> of the plate <NUM> and facing it, comprises a jig <NUM> that has a knurled surface. The lower structure <NUM> has through-holes for the respective pegs <NUM> of the fixed structure <NUM> of the machine <NUM>.

The machine <NUM> further comprises two control assemblies <NUM> of the respective grippers <NUM>, each of which comprises a linear actuator <NUM>, a lateral support <NUM> fixed to a respective side of the upper plane <NUM>, and a rod <NUM> hinged to the respective lateral support <NUM>.

Each rod <NUM> comprises an intermediate portion <NUM> hinged to the respective lateral support <NUM> by means of a hinge <NUM> having axis parallel to axis Y, an upper end <NUM>, and a lower end <NUM>.

The linear actuators <NUM>, preferably of pneumatic type, extend in a direction substantially parallel to the axis X and each one comprises a fixed part <NUM> hinged to a bracket <NUM> fixed to an upper end <NUM> of the wall <NUM>, and a movable shaft <NUM> hinged to the upper end <NUM> of the rod <NUM>.

At the lower end <NUM> of each rod <NUM> a stopping peg <NUM> with a cylindrical shape is fixed with axis parallel to the axis Y extending toward the respective gripper <NUM> below the crosspiece <NUM>.

The position of the peg <NUM> can be preferably set in longitudinal direction with respect to the rod <NUM>.

Each lateral support <NUM> further comprises two projections <NUM>, extending parallel to the axis Y, comprising at the top respective end-of-strokes <NUM>, facing each other, configured to interact with the rod <NUM> for defining the extreme angular positions of the rod.

As is noticeable from the comparison between <FIG> and between <FIG>, the control assemblies <NUM> are moved with respect to each other in the direction X of a quantity corresponding to the distance in the direction X between the axes of the pins <NUM>.

In particular, in a first end-of-stroke position of the rod <NUM>, corresponding to an extended position of the respective linear actuator <NUM> (<FIG>), the peg <NUM> is arranged below the first lower face <NUM> of the crosspiece <NUM> of the movable jaw <NUM> of the respective gripper <NUM>, and in a second end-of-stroke position of the rod <NUM>, corresponding to a retracted position of the respective linear actuator <NUM> (<FIG>), the peg <NUM> is arranged below the second lower face <NUM> of the crosspiece <NUM> of the movable jaw <NUM> of the respective gripper <NUM>.

The feeding system <NUM> comprises a handling assembly comprising a movable assembly X <NUM> and a movable assembly Y <NUM> carried by the movable assembly X <NUM>, and a terminal bracket <NUM> carried by the movable assembly Y and carrying a wire guide brushing <NUM>.

The movable assembly X <NUM> comprises two guides X <NUM>, parallel to the axis X and arranged along opposite sides of the base <NUM>, and two carriages X <NUM> slidable on the respective guides X <NUM> by means of respective sliding blocks <NUM> and a linear motor <NUM> associated with one of the guides X <NUM>. The carriages X <NUM> carry the movable assembly Y <NUM>.

The movable assembly Y <NUM> comprises a guide Y <NUM>, parallel to the axis Y and arranged at a greater height than the lower plane <NUM> and at a lower height than the wings <NUM> of the brackets <NUM>, and a carriage Y <NUM> slidable on the guide Y <NUM>, on the opposite side of the vertical wall <NUM> with respect to the guide Y <NUM>, by means of sliding blocks <NUM> and a linear motor <NUM> associated with the guide Y <NUM>.

The carriage Y <NUM> carries the bracket <NUM> substantially "L"-shaped and comprising a vertical arm <NUM>, extending along the axis Z and coupled to the carriage Y <NUM>, and a horizontal arm <NUM> extending along the axis X from a lower end of the vertical arm <NUM>.

The horizontal arm <NUM> faces the thrust element <NUM> and is arranged at a greater height than the lower plane <NUM> and at a lower height than the base surfaces <NUM> of the respective pegs <NUM>. The horizontal arm <NUM> has, at an end <NUM> thereof opposite with respect to the vertical arm <NUM>, a hole passing through the wire guide brushing <NUM> with vertical axis.

An upper end <NUM> of the wire guide brushing <NUM> is arranged at a greater height than the base surfaces <NUM> of the pegs <NUM> and at a lower height than the lower face <NUM> of the lower structure <NUM> when the thrust element <NUM> is at its upper end-of-stroke.

The wire guide brushing <NUM> has two degrees of linear freedom, since it can be moved by the feeding system <NUM> along the axes X and Y.

The wire is wound into a coil (not illustrated) from which it unwinds for arriving below the horizontal arm <NUM> of the bracket <NUM> and passing through the wire guide brushing <NUM> from the bottom upward. The feeding system <NUM> comprises a wire tensioning device of known type and not illustrated.

In the following, two working cycles are described in detail corresponding to the forming of respective antennas. The described cycles are consecutive and can be repeated indefinitely.

The initial conditions of the first cycle (<FIG>) are the following:.

Initially, the wire is passed around the pegs <NUM> by the wire guide brushing <NUM> so as to obtain the desired shape of the antenna.

During this wire winding step, the wire guide brushing <NUM> is handled as a whole from left to right by the feeding system <NUM>. In particular, the feeding system <NUM> modifies the coordinates of the wire guide brushing <NUM> along the axes X and Y so as to make the wire pass between the pegs <NUM> according to a predetermined path formed by rectilinear sections tangent to the pegs <NUM> alternated with curvilinear sections of partial or total winding around the pegs <NUM> (<FIG>). Therefore, the diameter and the positioning of the pegs <NUM> determine respectively the curvature and the position of the loops present in the curvilinear shape of the antenna. When the wire guide brushing <NUM> is on the right of the beak 88b of the fixed jaw 85b of the gripper 84b, the feeding system <NUM> stops. In particular, since the gripper 84b is open, the wire passes through the beaks 88b and 101b of the respective jaws 85b and 86b. Therefore, the wire is held in tension by the gripper 84a which is closed, by the friction with the lateral walls of the pegs <NUM>, and by the wire guide brushing <NUM>.

Subsequently, the movable structure <NUM> of the machine <NUM> moves vertically. In particular, the vertical actuator <NUM> causes in rapid succession the downward descent and the upward ascent of the thrust element <NUM>.

During the descent step of the thrust element <NUM>, more operations occur simultaneously:.

During the ascent step of the thrust element <NUM>, immediately subsequent to the descent step, more operations occur simultaneously:.

Alternatively, these operations can take place during the initial step of the second cycle, i.e. the wire winding step. In any case, these operations take place in masked time, i.e. parallel to other actions, thus they do not have an impact on the overall duration of the working cycle.

The initial conditions of the second cycle (<FIG>) are the following:.

Initially, the wire passes again around the pegs <NUM> so as to obtain the desired shape of the antenna.

During this wire winding step, the wire guide brushing <NUM> is handled as a whole from right to left by the feeding system <NUM>, in a dual manner with respect to what described in the corresponding step of the first cycle.

During the descent step of the thrust element <NUM>, the same operations of the corresponding step of the first cycle occur simultaneously, mutatis mutandis. In particular, the gripper 84a closes and cuts the wire separating the antenna that has just been formed, and the gripper 84b opens.

Alternatively, in similar manner to what said above, these operations can take place during the initial step of an immediately subsequent cycle.

The initial conditions of the cycle immediately subsequent to the second one coincide with the initial conditions of the first cycle. Therefore, the two described cycles can be applied repetitively in a sequence of arbitrary length.

By examining the characteristics of the machine <NUM>, the advantages of the present invention are evident.

In particular, the wire winding step, during which the desired shape of the antenna is obtained, is carried out exclusively by the feeding assembly <NUM> which moves the wire guide brushing <NUM> according to a predetermined path, and does not require any handling of other elements. Therefore, the forming of the antenna is very simple and is not subjected to the shape limitations connected to the use of a rotating forming device. Furthermore, since this step does not entail the handling of remarkable masses, dynamic problems are prevented.

The remaining steps necessary for obtaining the antenna deposited on the adhesive tape simply occur by means of a vertical handling of the thrust element <NUM>. In particular, the descent step of the thrust element <NUM> allows simultaneously obtaining the releasing of an end of the wire, the cutting and the contextual releasing of the other end of the wire, and the depositing of the antenna on the adhesive tape. Since this synchronization is due to mechanical interactions, it is exempt from errors and delays that could arise by controlling the operations singularly.

The other operations necessary for the continuous functioning of the machine <NUM> are carried out in masked time, i.e. parallel to other actions, thus do not have an impact on the overall duration of the working cycle.

Finally, it is clear that modifications and variations can be made to the machine <NUM> without departing from the scope of protection defined by the claims.

For example, the control assembly <NUM> could be made in a different manner. In particular, the commutation of the grippers <NUM> can be controlled by varying the position of the pegs <NUM> by means of actuators and/or kinematisms of different nature.

Furthermore, the grippers <NUM> could be made in a different manner and in particular symmetrically with respect to a middle longitudinal plane of the machine <NUM>, thus requiring an operation in counterphase of the linear actuators <NUM>.

Claim 1:
Machine for forming RFID antennas, comprising:
- a support structure (<NUM>) provided with a support (<NUM>) for an RFID substrate, and a plurality of forming pegs (<NUM>) having vertical axes fixed with respect to the support (<NUM>) and arranged above said support (<NUM>) so as to define a predetermined path for a wire configured to form the RFID antenna;
- a wire feeding system (<NUM>) comprising a wire guide element (<NUM>) and a handling assembly, configured to move the wire guide element (<NUM>) along mutually orthogonal horizontal axes so as to wind the wire at least partially around the forming pegs (<NUM>) and define said path;
- a pair of grippers (<NUM>) arranged at the ends of said path and operable to assume a closed position, in which the wire is blocked, and an open position, in which the wire is released; and
- a movable structure (<NUM>) carried by the support structure (<NUM>) and provided with a thrust element (<NUM>) movable vertically between an upper position in which said thrust element (<NUM>) allows the wire to be wound around the pegs (<NUM>) and a lower position in which said thrust element (<NUM>) deposits the formed antenna on the substrate.