Continuous manufacturing of pocketed coil springs

Abstract

The present invention relates to various devices and / or method for the production of pocketed springs which reduce the number of components having a discontinuous movement. Particular embodiments relate to devices for compression of coil springs, for longitudinal welding of fabric sheets in order to implement coil pockets, for the removal of coil springs from a coiler and for pocketing of coil springs.

Description

[0001] Continuous manufacturing of pocketed coil springs

[0002] The present invention relates to devices and methods for the continuous manufacturing of pocketed coil springs.

[0003] Prior art

[0004] In the manufacturing of mattresses for various objects, such as bed, couches, seats, etc. pocketed coil springs are usually employed. Pocketed coil springs are coil springs which have been included in a pocket so as to preload and contain the coil spring.

[0005] Pocketed coil springs can be realized with as little as two materials: a metallic wire for the coil spring and a flexible material for the pocket, such as non-woven fabric, etc. Pocketing machines are known which receive material for the coil spring and for the pocket and, from those, form the coil spring, the pocket and insert the coil spring into the pocket so as to produce the completed pocketed coil spring.

[0006] Those machines implement various steps for the forming of the coil spring, various steps for the forming of the pocket and various steps for the insertion of the coil spring into the pocket. All, or at least some of those steps are discontinuous, meaning that moving elements within the machine are moved to a first position, held there while other elements operate, and then moved again. Such discontinuity in the operation of the moving elements leads to various challenges such as complexity in the operation of the machine, wear in the elements, difficulty in managing tolerances, etc.

[0007] It would be preferable to have a continuous movement of the various elements through the manufacturing machine. That is, a movement which does not require elements to be stopped and started again, but instead allows a continuous movement, preferably at a substantially constant speed. This is particularly applicable to the materials forming the coil and the spring, and preferably applicable to the components inside the manufacturing machine.

[0008] Moreover, in previously known machines, such as the P-460 made from Spuhl GmbH, coil springs are compressed and transported through a folded fabric tube by means of two conveyor belts. In particular, a longitudinal welding of the folded fabric tube takes place before the coil springs are inserted into it.

[0009] The compressed coil springs are inserted into the folded fabric tube as a block by a double-stroke movement. Once inserted in the folded fabric tube, the coil springs open and the fabric tube is transverse welded so that pockets are created, each pocket containing at least one spring. The forward and backward stroke necessary for the insertion of the springs in the folded fabric tube is a limiting factor in the manufacturing speed, as such type of movement can only be operated to a certain speed

[0010] In general, it would be preferable to implement various manufacturing steps in a continuous manner, without intermittent movements or with a reduced number of elements carrying out intermittent movements.

[0011] Summary

[0012] The inventors have generally realized that various components and / or manufacturing processes can be configured such that their operation is performed in a continuous manner.

[0013] The invention is defined by the independent claims, the dependent claims providing further advantageous embodiments.

[0014] An embodiment can thus relate to a device for compression of coil springs, the device comprising: first conveying means configured to convey the coil springs along a first path at a first speed, wherein the first conveying means comprise a plurality of holding means, each of holding means configured to hold a respective coil spring, compressing means configured to compress the coil springs as they are conveyed along the first path, wherein the compressing means comprise two compressing plates, wherein the compressing means are configured to move the compressing plates toward each other so as to compress at least one coil spring between the compressing plates, wherein the compressing means is further configured to move the compressing plates along the first path at the first speed.

[0015] In some embodiments, the compressing means can be configured to position two compressing plates at a predetermined angle with respect to each other as the compressing plates can be moved along the first path.

[0016] In some embodiments, the device can further comprise a channel configured to receive the coil springs in a compressed state.

[0017] In some embodiments, the compressing means can be configured to remove a coil spring from the respective holding means in a at least partially compressed state.

[0018] In some embodiments, the first conveying means can be any of a conveyor belt, a conveyor chain, a rotating element.

[0019] In some embodiments, one or more of the holding means can comprise any of a magnet, pinching means, carrying means. In some embodiments, the compressing means can further comprise two second conveying means configured to move the compressing plates toward each other.

[0020] In some embodiments, the two second conveying means can be configured to move at a speed higher than the first speed.

[0021] In some embodiments, each of the two second conveying means can comprise a guiding rail and a conveyor belt.

[0022] In some embodiments, any of the compressing plates can have a first connection to the respective guiding rail and a second connection to the respective conveyor belt.

[0023] In some embodiments, any of the first connection and of the second connection can allow rotation between the two connected elements.

[0024] In some embodiments, the two second conveying means can rotate in opposite directions.

[0025] In some embodiments, the two second conveying means can extend further than the first conveying means in a direction along the first path.

[0026] In some embodiments, the compressing means can further comprise a third conveying means configured to move an actuator carrying the compressing plates.

[0027] A further embodiment can relate to a device for longitudinal welding of a folded fabric sheet for coil spring pockets, the device comprising: a sonotrode, an anvil configured to rotate around a rotation axis.

[0028] In some embodiments, the rotation axis is substantially parallel to a plane interpolating the folded fabric sheet, and / or is substantially perpendicular to a plane interpolating the anvil, and / or is substantially perpendicular to a direction connecting a center of rotation of the anvil and the sonotrode.

[0029] In some embodiments, the folded fabric sheet can be moved through the device at a first speed, the anvil can comprise a welding extremity, and the anvil can be configured to rotate so as to move the welding extremity with the first speed.

[0030] In some embodiments, the folded fabric sheet can be moved through the device at the first speed by pulling means.

[0031] In some embodiments, the anvil can be circular.

[0032] In some embodiments, the anvil can have a diameter larger than 5cm, preferably larger than 9Cm and / or smaller than 30cm, preferably smaller than 15cm. In some embodiments, the device can further comprise first moving means configured to move the anvil and the sonotrode together, along the rotation axis.

[0033] In some embodiments, the device can further comprise second moving means configured to move the anvil with respect to the sonotrode, or the sonotrode with respect to the anvil, along a direction perpendicular the rotation axis.

[0034] In some embodiments, the anvil can comprise a welding extremity, and the welding extremity can have a flat surface.

[0035] In some embodiments, the anvil can comprise a welding extremity, and the welding extremity can have a toothed surface.

[0036] In some embodiments, the anvil comprises a welding extremity, and the welding extremity can have a surface with an angle with respect to the rotation axis.

[0037] In some embodiments, the angle can be larger than 0 degrees, preferably larger than 10 degrees, and / or the angle can be smaller than 60 degrees, preferably smaller than 30 degrees.

[0038] A further embodiment can relate to a device for removing coil springs from a cutting section of a coiler, the device comprising: a plurality of holding means, each of the holding means being configured to hold a respective coil spring outputted by the cutting section, conveying means configured to convey the holding means, first actuating means configured to position one of the holding means so as to be substantially parallel with a coil spring at a time of cutting of the coil spring by the cutting section.

[0039] In some embodiments, one or more of the holding means can comprise any of a magnet, pinching means, carrying means.

[0040] In some embodiments, one or more of the holding means can comprise a first end and a second end, opposite the first end along a direction of elongation of the holding mean, the second end can be hingedly connected to the conveying means, the first actuating means can be configured to act on the first end.

[0041] In some embodiments, the first actuating means can be configured to lift the first end before the time of cutting of the coil spring by the cutting section, and / or the first actuating means can be configured to lower the first end after the time of cutting of the coil spring by the cutting section.

[0042] In some embodiments, one or more of the holding means can be configured to have a length at least equal to a length of the of coil springs. In some embodiments, the device can further comprise confining means configured to limit at least partially confine movement of the coil spring at the time of cutting of the coil spring by the cutting section, and second actuating means configured to position the confining means.

[0043] In some embodiments, the second actuating means can be configured to move the confining means towards the coil spring before the time of cutting of the coil spring by the cutting section, and / or the second actuating means can be configured to move the confining means away from the coil spring after the time of cutting of the coil spring by the cutting section.

[0044] In some embodiments, the confining means can be configured to allow movement of the coil spring in the direction of a holding means configured to hold the coil spring.

[0045] A further embodiment can relate to a device for pocketing coil springs into pocketed coil springs, the device comprising: a channel configured to guide the coil springs in a compressed state, longitudinal welding means configured to weld two extremities of a folded fabric sheet along a longitudinal welding to obtain a fabric tube, wherein the longitudinal welding means can be configured such that the fabric tube surrounds least one end of the channel, decompressing means configured to receive the coil springs from the channel in a compressed state and controllably reduce compression of the coil springs, transverse welding means configured to receive the coil springs from the decompressing means and to weld the fabric tube along a transverse welding to obtain pocketed coil springs comprising the coil springs.

[0046] In some embodiments, the decompressing means can comprise two plates configured to hold the extremities of the coil springs.

[0047] In some embodiments, the decompressing means can be configured to controllably reducing compression of the springs inside of the fabric tube.

[0048] In some embodiments, the decompressing means can be configured to move away from the channel while controllably reducing compression of the coil springs.

[0049] In some embodiments, the tube can be moved at a first speed, and the decompressing means can be configured to move away from the channel at the first speed.

[0050] In some embodiments, the decompressing means can be configured to move towards the channel after having controllably reduced compression of the coil springs.

[0051] In some embodiments, the decompressing means can be configured to move the two plates towards each other as the decompressing means move towards the channel. In some embodiments, the transverse welding means can be configured to move away from the channel while welding the fabric tube along the transverse welding.

[0052] In some embodiments, the tube can be moved at a first speed, and the transverse welding means can be configured to move away from the channel at the first speed.

[0053] In some embodiments, the transverse welding means can be configured to move towards the channel after having welded the fabric tube along the transverse welding.

[0054] In some embodiments, the decompressing means and the transverse welding means can be configured to move together.

[0055] In some embodiments, the decompressing means can be configured to operate along a first longitudinal length of the fabric tube, the transverse welding means can be configured to operate along a second longitudinal length of the fabric tube, and the first longitudinal length and the second longitudinal length have substantially the same length.

[0056] Brief description of the drawings

[0057] Figure 1A schematically illustrates a front view of elements of a device 100 for compression of coil springs;

[0058] Figure IB schematically illustrates a side view of the device 100;

[0059] Figure 1C schematically illustrates a top view of parts of the device 100;

[0060] Figure 2 schematically illustrates a front view of compressing means 220, together with an enlarged view of compressing plate 221b and conveying means 222b, the compressing means 220 can be an implementation of the compressing means 120;

[0061] Figure 3A schematically illustrates a front view of compressing means 320 of a device 300 for compression of coil springs, the compressing means 320 can be an implementation of the compressing means 120;

[0062] Figure 3B schematically illustrates a side view of the device 300;

[0063] Figure 4A schematically illustrates a front view of elements of a device 400 for longitudinal welding of coil spring pockets;

[0064] Figure 4B schematically illustrates a side view of elements of the device 400 together with an enlarged view of part of an anvil 410 and of a sonotrode 430; Figure 5 schematically illustrates a side view of elements of a device 500 for longitudinal welding of coil spring pockets;

[0065] Figure 6 schematically illustrates various possible implementations of anvil 610a, 610b, 610c;

[0066] Figure 7A schematically illustrates two front views of a cutting section CS of a coiler CO at different stages To and Ti, of producing a coil springs C;

[0067] Figure 7B schematically illustrates two side views corresponding to the front views of figure 7A;

[0068] Figure 7C schematically illustrates a front view of elements of a device 700 for removing coil springs C from a coiler at the two stages To and Ti of figures 7A, 7B, the coil spring C outputted from the coiler CO at the time To not being illustrates for clarity;

[0069] Figure 7D schematically illustrates a side view of the device 700;

[0070] Figure 7E and 7F schematically illustrates an enlarged front and side view of parts of the device 700;

[0071] Figure 8A schematically illustrates a front view of elements of a device 800 for removing coil springs C from a coiler at the two stages To and Ti of figures 7A, 7B;

[0072] Figure 8B schematically illustrates a side view of the device 800.

[0073] Figure 9A schematically illustrates a top view of elements of a device 900 for pocketing of coil springs, where the fabric sheet is only schematically illustrated;

[0074] Figure 9B schematically illustrates the same top view of figure 9A where the fabric is illustrated in full;

[0075] Figure 9C schematically illustrates a side view of device 900;

[0076] Figures 9D-9G schematically illustrates a top view of the operation of device 900;

[0077] Detailed description of preferred embodiments

[0078] Figure 1A schematically illustrates a front view of elements of a device 100 for compression of coil springs, figure IB schematically illustrates a side view of the device 100. It will be clear to those skilled in the art that not all components of the device 100 are illustrated, and not all components illustrated in one figure are also present in the other one, for clarity of illustration. For instance, elements 111 visible in figure IB are not visible in figure 1A, as they would be superimposed with the coil springs Ci- C5, rendering the illustration less clear.

[0079] As can be seen in figures 1A and IB, the device 100 is configured for a compression of coil springs Ci- C5and comprises first conveying means 110 configured to convey the coil springs C1-C5 along at least a first path Pi, at a first speed and compressing means 120 configured to compress the coil springs Ci- C5as they are conveyed along the first path Pi. In particular, the compressing means 120 are configured to move along the first path Pi at the first speed. In preferred embodiments, the compressing means comprise compressing plates, 121a, 121b, which will be described more in details in the following, and the compressing means 120 can be configured to move the compressing plates 121a, 121b along the first path Pi at the first speed. Thanks to this implementation, as will result more clearly from the following description, the compression of the coil springs C1-C5 can be achieved continuously along the first path Pi.

[0080] In particular, the first conveying means 110 can be implemented, for instance, by a conveyor belt, or a conveyor chain, a rotating element, or similar devices. Preferably, the first conveying means 110 are implemented in a closed loop, as visible in figure IB, where the direction of rotational movement is indicated as being in the clockwise direction, although the invention is not limited thereto. The first path Pi can be a portion of the closed loop, preferably with a linear shape, although the invention is not limited thereto.

[0081] The first conveying means 110 are in particular configured to convey the coil springs from a first loading location LL and through at least a first part of a compression process which will be described more in details in the following. Preferably, the first part of the compression process can be executed along the first path Pi. Even more preferably, the first part of the compression process begins at the beginning of the first path Pi and ends at the end of the first path Pi.

[0082] In particular, as will become clearer in the following, the compression process can have a first part and a second part. In some embodiments the coil springs C1-C5 may be conveyed by elements other than the first conveying means 110 for the second part of the compression process, which follows, preferably immediately, the first part of the compression process. The invention is however not be limited thereto and could be implemented without the second part of the compression process, which could be completed during the first part only.

[0083] In the implementation illustrated in the figures, the compression process comprises two parts. In particular, in the illustrated embodiment, the coil springs C1-C5 are compressed by compressing means 120, which will be described more in details in the following. During this compression, at the end of the first path Pi, the coils springs C1-C5 are released from the first conveying means 110 and transported by the compressing means 120, for the second path P?. In particular, the first conveying means 110 can be configured to release the coil springs as soon as, or later, the compression by the compressing means 120 ensures that the coil springs C1-C5 can be held by the compressing means 120. Alternatively, or in addition, the compressing means 120 can remove the coil springs C1-C5 from the conveying means 110.

[0084] For instance, the compressing means 120 can be configured to hold the coil springs C1-C5 along the second path P2, illustrated in the figures, without support from the conveying means 110. Preferably, the end of the first path Pi can correspond to the beginning of the second path P2. It is noted that this point is not necessarily corresponding to the most compressed state of the coil springs C1-C5, which can be reached at a later compression process. For instance, in the illustrated embodiment, the coil springs C1-C5 are still compressed during the second path P2, as can be seen comparing the compression state of coil spring C4, at the beginning of the second path P2, with respect to the more compressed state of coil spring C5, at the end of the second path P2. It will be clear to those skilled in the art that this is not necessary and the coil springs C1-C5 can be maintained at substantially the same compression state during the second path P2. It will be further clear that, in some embodiments, the second path might not be present, and the unloading location UK can be corresponding to the end of the first path Pi. That is, in some embodiments, the coil springs C1-C5 can be conveyed by the first conveying means 110 throughout the entire compression process. In general, therefore, the first conveying means 110 can be configured to at least retrieve coils springs C1-C5 from the loading location LL and convey them along the first path Pi, where they can undergo a compression process. At the end of the first path Pi, or, where present, at the end of a second path P2following the first path Pi, the coil springs can be positioned in a proximity of a channel 130, preferably in front of an entry portion of the channel 130, where they can be moved by pushing means PM away from the compression means 120 and into the channel 130.

[0085] In some embodiments, the device 100 can thus further comprise a channel 130, configured to receive the coil springs C1-C5 in a compressed state. The channel can be implemented by at least two parallel plates 131, 133, as visible in figure 1C. Thanks to this configuration, the coil springs C1-C5 can be loaded into the channel 130 in a compressed state, for subsequent inclusion in the pocket, for instance by having the pocket formed around the channel 130. That is, the material forming the pockets can be folded around the channel 130, and the two ends resulting from the fold can be welded, such that a tube of material encircles the channel 130. When the coil springs C1-C5 are released from the channel, they can thus expand into the tube of material, in a manner which will be described more in details in the following for instance with reference to figures 9A-9G.

[0086] Preferably, as illustrated, the positioning of the coil springs C1-C5 to the proximity of the channel 130 can be achieved by the compressing means 120 after the coil springs C1-C5 have been released from the conveying means. This is the configuration illustrated in the embodiment, where the coil springs C1-C5 are released from the conveying means 110 at the end of the first path Pi and they are further moved along the second path P2 by the compression means.

[0087] That is, the compressing means 120 can be configured to remove a coil spring, for instance C5in the illustrated embodiment, from the respective holding means 111, in a at least partially compressed state. The compressing means 120 can in particular be configured to remove the coil spring at the end of the first path Pi. In this case, the second path begins at the point where the coil springs Ci-C5are released from the conveying means 110 and / or ends at the proximity of the channel 130, at an unloading location UL, where the coil springs C1-C5 are moved into the channel by pushing means PM. The advantage of this configuration is that the conveying means 110 do not need to accompany the coil springs C1-C5 to the proximity of the channel, where the presence of the compression means 120, the channel 130, the means MM for pushing the coil springs C1-C5 into the channel 130 and the conveying means 110 might result difficult to manage. Moreover, the coil springs C1-C5 would have to be released, upon their movement into the channel 130, by both the compression means 120 and the conveying means 110, which is more complex than releasing them only from the compression means. On the other hand, by holding the coil springs C1-C5 through the compression means 120, it is advantageously possible to have a simplified release of the coil springs C1-C5 in order to move them into the channel 130.

[0088] The pushing means PM for moving the coil springs C1-C5 into the channel 130 could be elements capable of pushing the coil springs C1-C5 from the compression means 120 into the channel 130. Preferably, pushing means PM are configured to act at a time where the compression means 120 are positioned substantially in front of the channel 130, at the unloading location UL. The compression means 120 can be configured to compress the coil springs C1-C5, when at the unloading location UL, to a compression length which is less then, or equal to, a width CW of the channel 130. As previously discussed, this compression length can be achieved already during the first compression part of the compression process, with or without the presence of a second path P2. Alternatively, as illustrated, this compression length is achieved during the second compression part, with the presence of the second path P2.

[0089] Thanks to this configuration, the coil springs C1-C5 can be pushed into the channel 130 by the pushing means 130 while in a compressed state and while being carried by, at least, the compression means 120. Preferably, the compression means 120 are configured such that they allow movement of the coil springs C1-C5 in a direction substantially aligned with a direction of maximum longitudinal extension of the channel 130. This allows the movement of the coil springs C1-C5 from the compression means 120 into the channel 130. In the illustrated embodiment, this direction is direction Z. Alternatively, or in addition, the compression means 120 are configured such that they allow movement of the coil springs C1-C5 in a direction substantially aligned with a direction of maximum longitudinal extension of the second path P2, or, where not present, with a direction of maximum longitudinal extension of the first path Pi. Alternatively, or in addition, the compression means 120 are configured such that they allow movement of the coil springs C1-C5 in a direction substantially aligned with a direction of revel of the compression means 120 at the unloading location UL. In the illustrated embodiment, this direction is direction Y. This allows the compression means 120 to keep moving while the coil springs C1-C5 are being pushed into the channel 130. In particular, the pushing means PM can be configured to move the coil springs C1-C5 at a speed faster, preferably at least three times faster, than the compression means 120. As the pushing means PM operate, it is preferably to keep the compression means 120 moving, so as to allow a continuous operation of the compression means 120. Thus, even if the speed of travel of the pushing means PM is faster than that of the compression means 120, it is possible the coil springs C1-C5 might need to move, with respect to the compression means, not only in the direction towards the channel 130, but also in the direction of travel of the compression means 120 at the unloading location UL. By configuring the compression means 120 to allow for such movement, a continuous movement of the compression means 120 can be allowed.

[0090] It has thus been described how the compression means 120 can cooperate with the conveying means 110 to compress the coil springs C1-C5 along at least path Pi in order to bring the coil springs C1-C5 in a compressed state to an unloading location UL, where they are pushed into a channel 130 for further processing. As results from the above, the conveying means 110 and the compression means 120 can operate at a constant speed, without the need for a start / stop or other types of intermitting action, thus enabling an improved compression of the coil springs C1-C5 which does not suffer from the issues deriving from the intermittent operation of the devices known from the prior art. As described, the compression can take part over the first path Pi and, where present, also over a second path P2. Moreover, as described, the coil springs C1-C5 can be held by the conveying means 110 at least during the first path Pi, and preferably only during the first path Pi, if a second path P2is implemented. Preferably, the direction of movement of the compression means at the unloading location UL is perpendicular to the direction of movement of the pushing means PM.

[0091] As visible in figure IB, and not illustrated in figure 1A for clarity of illustration, the first conveying means 110 can comprise a plurality of holding means 111, each of holding means 111 configured to hold a respective coil spring C1-C5. Preferably, the holding means 111 are positioned at regular intervals along the first conveying means 110, in the direction of movement of the first conveying means 110, although the invention is not limited thereto. The purpose of the holding means 111 is to provide support, or to hold, for one coil spring C1-C5 per holding mean, as illustrated, or more than one coil spring, at least during the first path Pi. The holding means 111 can be loaded with the respective coil spring, or can collect or grab the respective coil spring, from a non-illustrated device, at the loading location LL. For instance, a coiler such as coiler CO in Figure 7A can be implemented to form the coil springs, and the conveying means 110 can be configured such that the holding means 111 receive the coil springs C1-C5 from the coiler directly or through one or more intermediate conveying means, not illustrated.

[0092] It will be evident to those skilled in the art that the holding means 111 can be implemented in a plurality of manners. In principle, any mechanism which allows springs Ci-C5to be held by the holding means as those are moved by the first conveying means 110 can be implemented, which is why the figures only schematically represent the holding means 111. In preferred embodiments, one or more of the holding means 111 can in particular comprise any of a magnet, pinching means, carrying means, or any of their combinations.

[0093] More specifically, the magnet can hold a coil made of, or containing, ferromagnetic metal in a known manner. The magnet can be a permanent magnet, which simplifies the implementation of the holding means 111, or can be an electromagnetic magnet, which can simplify the attaching and detaching of the coil springs Ci-C5from the holding means 111. Pinching means can be implemented by any device capable of pinching at least parts of the coil spring resulting in the coil spring being held by the pinching action. Preferably the pinching means can comprise two arms, at least one of which is movable so as to change the distance between the two arms. By placing a portion of the coil spring in between the arms, the pinching action can secure the coil spring with respect to the pinching means. Carrying means can be implemented by any device which can engage with a coil spring, or part thereof, under the action of gravity. For instance, a device with two or more arms can be configured so that the arms can engage the spring coil and lift it. The skilled person will easily recognize that a wide variety of mechanical configuration can implement such function, so that a structural description of all possible implementations is not possible.

[0094] In the drawings, the direction Y is the vertical direction, which form a possible embodiment, while it is clear that the invention is not limited thereto. Preferably, the first path Pi along which the coil springs C1-C5 are conveyed comprise at least a portion which has an angle with respect to the vertical orientation, when the device is in use, of at most 35°, preferably at most 10°. While this is not limiting of the invention, such implementation is advantageous in cases where, as described above, the holding means 110 are implemented as carrying means. It will be clear that the first path Pi is not necessarily straight, although a straight implementation results in a potentially simpler configuration of the device 100, in particular with respect to the implementation of the compressing means 120, described in the following. As illustrated, the compressing means 120 comprise two compressing plates 121a, 121b and are generally configured to move the compressing plates 121a, 121b toward each other so as to compress at least one coil spring C1-C5 between the compressing plates 121a, 121b. In particular, while in the illustrated embodiment only one coil spring C1-C5 is compressed by any two compressing plates 121a, 121b, the invention is not limited thereto and it might be possible to compress more than one coil spring Ci-C5by a couple of compressing plates 121a, 121b.

[0095] In some embodiments, the compressing means 120 can be configured to position two corresponding compressing plates 121a, 121b at a predetermined angle with respect to each other, as the compressing plates 121a, 121b are moved along the first path Pi. The angle can be defined by the smallest angle given by the intersection of the planes corresponding to the compressing plates 121a, 121b.

[0096] In the illustrated embodiment, this angle is substantially zero. That is, compressing plates 121a, 121b of a given pair, acting on a given coil spring, are substantially parallel to each other. Nevertheless, the invention is not limited thereto and, in preferred embodiments, the compressing plates 121a, 121b might be positioned at an angle different from zero, as that might be preferable for the compression of various types of coil springs. For instance, coil springs which are not linear, but are bent, as in a banana-form, might better be compressed by compressing plates which are not parallel to each other. Thus, in preferred embodiments, this angle can be smaller than 20°, even more preferably smaller than 10°. Even more preferable, the angle can be selected such that compressing plate 121a is positioned parallel to a first end coil of the coil spring, and compressing plate 121b is positioned parallel to a second end coil of the coil spring, at the opposite side of the coil spring with respect to the first end coil.

[0097] It will be clear to those skilled in the art that the compressing means can be configured in a plurality of manners for moving the compressing plates 121a, 121b towards each other.

[0098] For instance, an actuator might be provided for a given pair of compressing plates 121a, 121b, configured to move one or more of the compressing plates 121a, 121b so as to move them towards each other. Such actuator can be mounted on the conveying means 110 or, alternatively, as illustrated in figure 3, on a separate conveying means 326. That is, in some embodiments, the compressing means 320 can further comprise a conveying means 326 configured to move an actuator 327 carrying the compressing plates 121a, 121b, and generally configured to move one or more of the compressing plates so that the distance between the compressing plates 121a, 121b can be reduced, resulting in a compression of the coil spring C1-C5. As disable in figure 3B, the direction of rotation of the conveying means 326 is preferably opposite to the direction of rotation of the conveying means 110. This allows the one or more actuators 327. mounted on the conveying means 326, to be brought to face the coil spring C1-C5 as they are moved by the conveying means 110. Preferably, the conveying means 326 are configured to that the actuators 327 move along the first path Pi and, where present, along the second path P2. The conveying means 326 is preferably configured to move at a speed corresponding to the first speed, so that the alignment between the actuators 327 and the coil spring C1-C5 can be ensured. As they move, the actuators 327 are configured to move the compressing plates 121a, 121b, so as to result in the previously described compression.

[0099] An alternative implementation for moving the compression plates 121a, 121b, is schematically illustrated by the compressing means 220 of figure 2.

[0100] In the illustrated implementation, the compressing means 220 comprise two conveying means 222a, 222b configured to move the compressing plates 221a, 221b toward each other. As will result more clearly from the following description, this allows a simple and effective implementation of the compressing means 220.

[0101] In particular, a first conveying means 222a is configured to carry a plurality of compressing plates 221a, while a second conveying means 222b is configured to carry a plurality of compressing plates 221b. In preferable embodiments, the two conveying means 222a, 222b are symmetrical with respect to a plane, the plane preferably crossing the coil springs perpendicularly to the elongation direction of the coil springs. In the illustrated embodiment, this is plane YZ.

[0102] In preferred embodiments, the conveying means 222a and 222b are configured to present an angle, with respect to a direction of movement of the compressing means 110 along the first path Pi. in the illustrated embodiment, this direction is corresponding to the Y axis. The angle can be preferably higher than 5°, even more preferably higher than 10°, and / or smaller than 45°, even more preferably smaller than 30°.

[0103] The two conveying means 222a, 222b, are configured to rotate in opposite directions, preferably at the same speed. The rotation speed of the two second conveying means 222a, 222b is preferably higher than the first speed of the conveying means 110. In particular, the rotation speed of the conveying means 222a, 222b can preferably be selected so that their speed along the direction of movement of the conveying means (110 in the first path Pi, namely direction Y in the illustrated embodiments, corresponds to the rotation speed of the conveying means 110. This advantageously enable the compressing plates 221a, 222b to move together with a corresponding holding means 111.

[0104] As visible in figure 2, when a second path P2 is implemented, the two conveying means 222a, 222b can be configured to extend further than the first conveying means 110 in a direction along the first path Pi. In the illustrated embodiment, this is corresponding to the Y direction. This is particularly advantageous, as previously described, as it allows the coil springs C1-C5 to be removed from conveying means 110 by the compressing means 120, which then keep moving them away from the conveying means, to an unload location UL.

[0105] Also as visible in figure 2, when a second path P2is implemented, the two conveying means 222a, 222b can be configured to be substantially parallel along the second path P2, so that the coil springs C1-C5 are not compressed along the second path P2, although the invention in not limited thereto, and the coil springs C1-C5 could be further compressed along the second path P2.

[0106] In preferred embodiments, each of the two second conveying means 222a, 222b comprises a guiding rail 223 and a conveyor belt 224.

[0107] The conveyor belt 224 is generally configured to move the compressing plates 221a, 221b. This can be achieved by connecting the compressing plates 221a, 221b to the conveyor belt 224, preferably by a connection allowing a rotation of the compressing plates 221a, 221b with respect to the conveyor belt 224. The guiding rail 223 can be generally configured to control the orientation in space of the compressing plates 221a, 221b as they are moved by the conveyor belt 224. Preferably, the compressing plates 221a, 221b are guided along the guiding rail 223 by a connection allowing translation of the compressing plates 221a, 221b along the guiding rail 223. Thus, as visible in the enlarged portion of figure 2, any of the compressing plates 221a, 221b can, in particular, have a first connection 225a to the respective guiding rail 223 and a second connection 225b to the respective conveyor belt 224. Preferably, the first connection 225a allows only translation of the compressing plates 221a, 221b with respect to the guiding rail 223, although in some embodiments it might also allow rotation between the two elements. Alternatively, or in addition, the second connection 225b allows only rotation of the compressing plates 221a, 221b with respect to the conveyor belt 224.

[0108] Thanks to this implementation, the compression plates 221a, 221b can be oriented correctly for the compression of the springs by appropriately configuring the guiding rail 223 and / or the conveyor belt 224.

[0109] In the illustrated embodiment, the conveyor belt 224 is provided with arms 224a, extending away from the conveyor belt 224, wherein the second connection 225b is connected to an extremity of the arm 224a, opposite to the conveyor belt 224. It will however be clear that the invention is not limited thereto, and the second connection 225b can be connected to the conveyor belt 224 without arms 224a.

[0110] In some alternative embodiments, a second guiding rail can be present, and the compressing plates 221a, 221b can be connected to the second guiding rail with a third connection, allowing translation of the compressing plates 221a, 221b along the second guiding rail. This can provide an improved control on the orientation in space of the compressing plates 221a, 221b, since the positioning dictated by the two fixed guiding rails can result more precise than the positioning dictated by the flexible conveyor belt 224. In those embodiments it is moreover possible to implement the compressing means 220 without the conveyor belt 224, and instead move the compressing plates 221a, 221b in other manners. For instance, the compressing plates 221a, 221b can be actuated, at portion of their travel along the guiding rails, and the subsequent compressing plates 221a, 221b along the guiding rails can push each other as result of this actuation.

[0111] It has thus been described how a device for the compression of coil springs can be advantageously implemented comprising mainly, or even consisting only, of components which are actuated with a continuous movement, opposed to the prior art, in which several components were actuated with intermitted, or discontinuous, movements resulting in the mentioned disadvantages.

[0112] Figure 4A schematically illustrates a front view of elements of a device 400 for longitudinal welding of coil spring pockets. Figure 4B schematically illustrates a side view of elements of the device 400 together with an enlarged view of part of an anvil 410 and of a sonotrode 430.

[0113] Generally, the device 400 is configured for the longitudinal welding of a folded fabric sheet FFS so as to result in a plurality of coil spring pockets, such as the pockets P illustrated in figure 9A. As can be seen in figure 4A, the device 400 comprises a sonotrode 430 and an anvil 410, configured to rotate around a rotation axis AR. The rotation can be ensured by moving means 420, connected to the anvil 410. This is in contrast with prior art devices, in which the anvil 410 is moved linearly towards the sonotrode, to perform welding, and then away from the sonotrode, to allow for the movement of the folded fabric sheet FFS. Thanks to the rotation of the anvil 410, instead of a linear back and forth movement, the disruptive effect of discontinuous movements can be avoided. This is not only true for the movement of the anvil 410, but also for the folded fabric sheet FFS, the movement of which can also be made continuous. In this manner, the welding speed can be increased considerably, and quality can be increased at the same time.

[0114] In particular, as also visible in figure 9B and 9C, a fabric sheet FS is folded along a folding line FL. In preferred embodiments, the folding is implemented around channel 930, so that the folded fabric sheet, when welded on an extremity opposite the folding line FL, results in a fabric tube surrounding at least part of the channel 930. In general, however, the invention can also be implemented without folding the fabric sheet FS around the channel 930.

[0115] In the embodiment illustrated in figure 4A, it is understood that the fabric sheet moves, when the device 400 is operational, from right to left. In general, as can be seen in figure 4A, folding means FM are configured to fold the fabric sheet FS around folding line FL, resulting in a folded fabric sheet FFS. The folding line can be advantageously positioned at approximately half of the width of the fabric sheet FS, although the invention is not limited thereto. The width will be understood as being the dimension of the fabric sheet FS perpendicular to the longitudinal movement of the fabric sheet FS in the device 400. In the illustrated embodiment, the width is along direction Y. Approximately half of the width can be understood to mean, in some embodiments, in a region within 5% of the total width, measured from the half width position.

[0116] It will however be clear to those skilled in the art that, in some embodiments, the fabric sheet FS can already be provided folded, so that no folding means FM are necessary.

[0117] The device 400 is then configured to position an extremity of the folded fabric sheet FFS, opposite the folding line FL, in between the sonotrode 430 and the anvil 410, so as to result in a longitudinal weld WL being implemented. As described above, this is achieved by rotating the anvil 410 around a rotation axis AR in the proximity of the sonotrode 430.

[0118] In particular, in some embodiments the rotation axis AR can be substantially parallel to a plane interpolating the folded fabric sheet FFS. In the illustrated embodiments, this plane corresponds to the plane XY and the rotation axis AR corresponds to the direction Y. The term substantially parallel can be understood to mean that an angle between the plane and the rotation axis AR is smaller than 10°, preferably smaller than 5°.

[0119] Alternatively, or in addition, in some embodiments the rotation axis AR can be substantially perpendicular to a plane interpolating the anvil 410. In particular, the anvil 410 can have a substantially planar shape. In the illustrated embodiments, this plane corresponds to the plane ZY and the rotation axis AR corresponds to the direction Y. The term substantially parallel can be understood to mean that an angle between the plane and the rotation axis AR is higher than 80°, preferably higher than 85°.

[0120] Further alternatively, or in addition, in some embodiments the rotation axis AR is substantially perpendicular to a direction connecting a center of rotation of the anvil 410 and the sonotrode 430, preferably an extremity of the sonotrode 430 closes to the anvil 410. In the illustrated embodiments, this direction corresponds to direction Z, and the rotation axis AR corresponds to the direction Y.

[0121] In preferred embodiments, the folded fabric sheet FFS is moved through the device 400 at a first speed. The movement of the folded fabric sheet FFS can be obtained by, for instance pulling means 440, which pull the folded fabric sheet FFS downstream of the anvil 410. One possible implementation of the pulling means 440 can be, for instance, the decompressing means 980, and / or the transverse welding means 960, which described with reference to figure 9A. As visible in the enlarged portion of figure 4B, the anvil 410 comprises a welding extremity 411 and the anvil 410 is configured to rotate so as to move the welding extremity 411 with the first speed. Thanks to this implementation, the anvil does not need to pull or push the folded fabric sheet FFS, which instead moves at the same speed of the anvil 410. This enables the distance D between the anvil 410 and the sonotrode 430 to be set at a value low enough for their operation, without risking damaging the fabric sheet, even at high speeds.

[0122] As visible in figure 6, in preferred embodiments the anvil 410, schematically illustrated by specific implementations 610a, 610b, 610c, is preferably circular. In preferred embodiments, the anvil has a diameter larger than 5cm, preferably larger than 9Cm and / or smaller than 30cm, preferably smaller than 15cm.

[0123] As previously described, the anvil comprises a welding extremity 411. As visible in figure 6, and in particular in the implementation of the anvil 610a, the welding extremity 411 can have a flat surface. Moreover, the surface 411 can extend in a direction, direction Y in figure 6, which is substantially perpendicular to the plane on which the anvil rotates, plane XZ in figure 6. The present invention is however not limited thereto. In alternative embodiments, as also visible in figure 6, the anvil 610b can comprise a welding extremity 411 with a toothed surface. That is, a plurality of indentations can be present along the external surface of the anvil which faces the sonotrode 430. This has been found to be preferable in practical implementations, as it allows an easy control of the welding process. Still alternatively, or in addition, as visible in figure 6, the anvil 610c can comprise a welding extremity 411 with a surface with an angle O with respect to the rotation axis AR. This advantageously allows avoiding collision with the folded fabric sheet FFS and it also improves space management between the anvil and the sonotrode. In embodiments in which the angle is provided, the angle O can be larger than 0 degrees, preferably larger than 10 degrees, and / or smaller than 60 degrees, preferably smaller than 30 degrees.

[0124] As visible in figure 5, in some embodiments the device for longitudinal welding of coil spring pockets can be implemented as device 500. Device 500 differs from device 400 due to the additional presence of moving means 540 configured to move the anvil 410 and the sonotrode 430 together, along the rotation axis AR. In the illustrated embodiment, the movement is thus along the axis Y. The movement can be in particular a translation of the anvil 410 and the sonotrode 430. Thanks to this implementation it is possible to control the position, on the folded fabric sheet FFS, of the longitudinal weld WL. This enables the device 500 to implement pockets having different heights, potentially within the same folded fabric sheet FFS. This can be useful, for instance, when different heights of the pockets are needed in a single string of pockets. Alternatively, or in addition, the device 500 differs from device 400 due to the presence of moving means 550a, 550b configured to move the anvil 410 with respect to the sonotrode 430, and / or the sonotrode 430 with respect to the anvil 410, along a direction perpendicular the rotation axis AR. Preferably, the direction of movement is parallel to a movement direction of the folded fabric sheet FFS. In the illustrated embodiments, the direction of movement of the moving means 550a, 550b corresponds to direction X. Thanks to this implementation it is possible to control the distance D between the anvil 410 and the sonotrode 430.

[0125] This can be done once, at setting of the device and based on the characteristics of the folded fabric sheet FFS. Alternatively, or in addition, the adjustment of the distance D can be executed during operation of the device 500, preferably on the basis of a feedback resulting from measurement of one or more characteristics of the longitudinal weld WL. The measurement can be performed, in preferred embodiments, by a sensor placed downstream, along the direction of movement of the folded fabric sheet FFS, with respect to the anvil and sonotrode. Alternatively, or in addition, the measurement can also be performed by computation based on welding characteristics, such as power used for the welding, etc. Those implementation advantageously allow to take into account changes in the longitudinal weld WL, which might occur during manufacturing for various reasons.

[0126] It has thus been described how pockets can be manufactured with a continuous movement of the anvil of the fabric sheet FS. Moreover, it has been described how the device can be configured to achieve pockets of different heights, potentially changing height from a pocket to the subsequent one.

[0127] The coil springs which are to be compressed, for instance by the devices described in conjunction with figures 1A-3B, are generally manufactures by a coiler CO, with a method per-se known. Generally, this method involves forming a coil from a metallic wire by appropriately bending the wire, and then cutting it. The cutting generally occurs at a cutting section CS, in a manner also per-se known.

[0128] Figure 7A schematically illustrates two front views of a cutting section CS of a coiler CO at different stages To and Ti, of producing a coil springs C. Figure 7B schematically illustrates two side views corresponding to the front views of figure 7A. As can be seen, the coil spring C is outputted from the coiler CO and, at a time Ti, or later, it is cut by the cutting section, making it possible to remove the coil spring C from the coiler CO. As schematically illustrated, the coil spring C is likely to have an orientation in which a first extremity of the coil spring C, opposite the second extremity of the coil spring C being cut by the cutting section CS, is lower in space than the second extremity, due to the action of gravity. The invention is however not limited thereto, as it will be clear that the orientation in space of the coil spring C can be controlled by controlling how the wire is bent and / or cut. It will therefore be possible to have implementations in which the spring coil C is substantially parallel with the horizontal direction, namely direction X in figure 7B.

[0129] Before being compressed, the coil springs C outputted by the coiler CO needs to be collected from the coiler CO, downstream of the cutting section CS. In the following, description will be provided of a device 700, 800 for removing coil springs C from a cutting section CS of a coiler CO.

[0130] In particular, figure 7C schematically illustrates a front view of elements of a device 700 for removing coil springs C from a coiler at the two stages To and Ti of figures 7A, 7B. In figure 7C, the coil spring C outputted from the coiler CO at the time To is not illustrates for clarity. Figure 7D schematically illustrates a side view of the device 700. Figure 7E and 7F schematically illustrates an enlarged front and side view of parts of the device 700.

[0131] As can be seen in the figures, the device 700 comprises a plurality of holding means 711, each of the holding means 711 being configured to hold a respective coil spring C outputted by the cutting section CS. In preferred embodiments, one or more of the holding means 711, preferably each of the holding means 711, comprises any of a magnet, pinching means, carrying means, or any of their combination. In particular, the holding means 711 can be understood to be an implementation of the holding means 111 previously described, so that the description of the holding means 111 also applies to the holding means 711. Alternatively, or in addition, the holding means 711 can be implemented in a manner similar to the holding means 111 previously described, but separately from, and / or in addition to, the holding means 111.

[0132] In addition to the holding means 711, the device 700 comprises conveying means 710 configured to convey the holding means 711. In particular, the conveying means 710 can be understood to be an implementation of the conveying means 110 previously described, so that the description of the conveying means 710 also applies to the conveying means 110. Alternatively, or in addition, the conveying means 710 can be implemented in a manner similar to the conveying means 110 previously described, but separately from, and / or in addition to, the conveying means 710. It will be understood that the conveying means 710 and the conveying means 110 have different shapes as they are only schematically represented in the respective embodiments to clarify the description of the embodiments and are not limited to the specifically illustrated shapes.

[0133] In preferred embodiments, the previously described loading location LL might be implemented at the location at which the conveying means 710 receive a coil spring C from the coiler CO.

[0134] Still further, the device 700 comprises actuating means 720 configured to position one of the holding means 711 so as to be substantially parallel with a coil spring C at a time of cutting of the coil spring C by the cutting section CS. More specifically, the coil spring C can be interpolated by a first linear direction in space, and the holding means 711 configured to receive the coil spring C can be interpolated by a second plane in space. In preferred embodiments, the holding means 711 can be configured such that the second plane has an orientation, with respect to the horizontal direction, that is, direction X in the figures, adjustable between 0 and 60 degrees, preferably between 0 and 45 degrees. This has been found to be a range of positions which allow a correct alignment of the holding means 711 with the first linear direction interpolating the spring coil C. Thanks to this configuration, the holding means 711 can be put in a position which facilitates the receipt of the coil spring C. In particular, the parallelism allows the holding means 711 to be moved close to the coil spring C, which reduces the possibility of the coil spring C not being correctly received by the holding means 711. Moreover, the parallelism avoids an extremity of the coil spring C to hit the holding means 711, with an angle between them, which would likely cause the coil spring C to bounce, potentially falling out of the holding means 711.

[0135] As can be seen in figures 7E and 7F, one or more of the holding means 711, preferably each of the holding means 711, comprises a first end 712 and a second end 713, opposite the first end 712, along a direction of elongation of the holding means 711. The direction of elongation can correspond to a direction of maximum elongation of the holding means 711. Alternatively, the direction of elongation can correspond to the first linear direction in space of the coil spring C, as described above. In the illustrated drawings, this direction is corresponding to the direction X, in the position illustrated at time To. In preferred embodiments, the holding means 711 can be configured to have a length at least equal to a length CLof the of coil springs C, preferably along the direction of elongation as described.

[0136] Preferably, the second end 713 is hingedly connected to the conveying means 710. This enables the movement of the holding means 711 visible when comparing the position of the holding means 711 at time To and Ti. Advantageously, when the holding means are oriented in a substantially horizontal position in the absence of other elements acting on them, this also ensures that, in the absence of such other elements, the holding means 711 automatically return to this position.

[0137] In the device 700, the actuating means 720 are configured to act on the first end 712. In particular, in preferred embodiments, the actuating means 720 can be generally configured to lift the first end 712, before the time of cutting of the coil spring C by the cutting section CS, thus moving them from the position illustrated at time Toto the position illustrated at time Ti. Alternatively, or in addition, the actuating means 720 can be configured to lower the first end 712 after the time of cutting of the coil spring C by the cutting section CS. The invention is however not limited thereto and, as previously described, this could be achieved by gravity, upon returning the actuating means 720 to the position illustrated at time To. The actuating means 720 can be implemented by any device which can be controller to move the holding means 711 as described. It will be evident to those skilled in the art that this can be achieved by, for instance, a cam, a linear actuator, a piston, a magnet, or similar devices. Alternatively, or in addition, the actuating means 720 can be a fixed element with a predetermined shape, and positioned such that the end 712 slides over them. By controlling the shape of the actuating means 720, the raising by interference of the end 712 can result in the described movement.

[0138] The device 700 thus allows the conveying means 710 to position holding means 711 in proximity of a cutting section CS, and to lift one side of the holding means 711 through the actuating means 720, so that holding means 711 become substantially parallel to the coil spring C. The coil spring C, released from the cutting section CS can then be received in the holding means 711, which can be lowered to their position in the absence of a force exerted by the actuating means 720.

[0139] In preferred embodiments, the actuating means 720 are actuated as the holding means are moved by the conveying means. That is, with reference to the illustrated embodiments, as the holding means move in the Z direction, the actuating means 720 can cause the end 712 to move in the Y direction. In this manner, the device 700 can operated in a continuous movement, avoiding intermittent operation.

[0140] Figure 8A schematically illustrates a front view of elements of a device 800 for removing coil springs C from a coiler at the two stages To and Ti of figures 7A, 7B. Figure 8B schematically illustrates a side view of the device 800.

[0141] Device 800 differs from device 700 due to the presence of confining means 840, configured to limit at least partially confine movement of the coil spring C at the time of cutting of the coil spring C by the cutting section CS. The confining means 840 can therefore be implemented by any element which mechanically limits movement of the coil spring C in space. In the illustrated embodiments, the confining means 840 are implemented in an L shape having a first wall and a second wall, perpendicular to the first wall. The first and second walls are configured to be positioned such that the first wall limits movement of the coil spring C in a direction opposite the holding means 711 and / or such that the second wall limits movement of the coil spring C in a direction of travel of the conveying means 710. Alternatively, or in addition, the confining means 840 can be configured to allow movement of the coil spring C in the direction of the holding means 711 configured to hold the coil spring C being outputted by the coiler CO. In some embodiments, the confining means 840 can be implemented with only one of the two walls.

[0142] As it will result evident to those skilled in the art, the confining means 840 enable a confinement in space of the coil spring C, thus reducing the risk of the coil spring C not being correctly loaded in the holding means 711. Additionally, device 800 might comprise actuating means 850, configured to position the confining means 840. It is noted, however, that the invention is not limited thereto, and the confining means might instead be fixed in space. In preferred embodiments, the actuating means 850 can be configured to move the confining means 840 towards the coil spring C before the time of cutting of the coil spring C by the cutting section CS, and / or to move the confining means 840 away from the coil spring C after the time of cutting of the coil spring C by the cutting section CS. Preferably, the actuating means 850 can be configured such that the approaching movement of the confining means 840 towards the coil spring C has a direction which is the sum of a first vector, oriented parallel and opposite to the direction of movement of the conveying means 710, and a second vector, oriented perpendicularly to the first vector, in a direction from the coil spring C towards the conveying means 710. In the illustrated embodiment, the first vector is thus understood to correspond to the negative Z axis, and the second vector is understood to be corresponding to the negative Y axis. In further preferred embodiments, the approaching movement of the confining means 840 towards the coil spring C has a direction which is the sum the described first and second vectors as well as a third vector, oriented substantially perpendicular to the first and second vector and towards the coiler CO. In the illustrated embodiment, the third vector is understood to correspond to the negative X axis.

[0143] It has thus been described how the actuating means 850 can move the confining means 840 from a position away from the spring coil C towards a position closer to the spring coil C, so that the closest position of the confining means 840 with respect to the spring coil C is achieved at the time at which the cutting section CS cuts the spring coil C. In this manner, movement of the spring coil C at the cutting time is contained and the spring coil C is directed towards the holding means 711, even at a relatively high speed of operation of the coiler CO and / or of the conveying means 710. The actuating means 850 can then move the confining means 840 away from the coil spring C in a direction opposite to the approaching direction.

[0144] In the following, a device 900 for the pocketing of the coil springs will be described with reference to figures 9A-9G.

[0145] In particular, figure 9A schematically illustrates a top view of elements of a device 900 for pocketing of coil springs C1-C5, where the fabric sheet FS is only schematically illustrated by the two extremities, during the folding portion on the right side of the figure, and by the longitudinal weld WL, on the left side of the figure, so as allow visibility of elements which would otherwise covered by the fabric sheet FS. Figure 9B, on the other hand, schematically illustrates the same top view of figure 9A where the fabric sheet FS is illustrated in full, so as to cover elements which are not visible under it from this view. Figure 9C schematically illustrates a side view of device 900, without the coils and without one plate 982 in front of the compressed pocket, for clarity of illustration. Also in this case, the fabric sheet is only illustrated by the outlines thereof, to enable viewing of components which would otherwise be covered by it.

[0146] The device 900 is generally configured for pocketing coil springs Ci-Cn into pocketed coil springs P1-P3. That is, the device is configured to pocket each coil in a corresponding pocket. With reference to figure 9A, device 900 comprises a channel 930 configured to guide the coil springs Ci-Cn in a compressed state. The channel 930 can be an implementation of channel 130, previously described.

[0147] The device 900 further comprises longitudinal welding means 970, generally configured to weld two extremities of a folded fabric sheet FFS along a longitudinal welding WL to obtain a fabric tube T. The considerations previously made in the description for the folded fabric sheet FFS also apply for device 900. It will be understood that the sonotrode and anvil of devices 400 and 500 can be a specific implementation of the longitudinal welding means 970. In general, the longitudinal welding means 970 are configured such that the fabric tube T surrounds least one end 933 of the channel 930.

[0148] Thanks to this arrangement, the coil springs exiting the channel 930 expand into the fabric tube T. By means of welding the tube in the transversal direction, as will be described in the following, the coil springs are thus placed in corresponding fabric pockets.

[0149] In order to control the expanding of the coil springs upon exiting the channel 930, the device 900 comprises decompressing means 980, configured to receive the coil springs Ci-Cn from the channel 930 in a compressed state, and to controllably reduce compression of the coil springs Ci-Cu. That is the decompressing means 980 are configured to reduce compression of the coil springs Ci-Cn while maintaining pressure on the two extremities of the coil springs Ci-Cn. In other words, operation of the decompressing means 980 ensures that the coil springs expand in a controlled means, so that the fabric tube T is not damaged by the energy stored in the compressed coil springs being released at once.

[0150] In particular, in preferred embodiments, the decompressing means 980 comprise two plates 981, 982 configured to hold the extremities of one of the coil springs Ci-Cn outputted from the channel 930. The plates 981, 982, are preferably parallel to the at least two corresponding plates of the channel 930, previously described as plates 131, 132. Preferably, the decompressing means 980 are configured so as to position the plates 981, 982 at a distance between them equal to, or larger than, the distance between the plates 131, 132, at the time of receiving a compressed spring from the channel. This facilitates the passage of the spring from the channel into the decompressing means 980.

[0151] Operatively, the decompressing means are generally configured so as to provide a force contrary to the expanding force of the compressed spring, while allowing the compressed spring to expand in a controller manner. That is, the decompressing means 980 are configured to controllably reducing compression of the springs Ci-Cn inside of the fabric tube T. Thanks to this controlled expansion, it is possible to controllably open a given coil spring instead of letting it spring open as soon as it leaves the channel 930, so that damage to the tube T is avoided. Moreover, this can be achieved even when the coil springs have a very high pre-tension in the channel 930 and independently of the pre-tension value, so that different coil springs can be pocketed without the need to change process. Furthermore, the controlled release of the coil springs is particularly advantageous when the coil springs have asymmetric shapes, where the uncontrolled opening could position the springs in a wrong directions within the tube T.

[0152] Figures 9D-9G schematically illustrates a top view of the operation of device 900. As visible in those figures, the decompressing means 980 are configured to move away from the channel 930, in particular away from end 933, opposite to the end of the channel 930 where the coil springs are inserted, while controllably reducing compression of the coil spring C2, in the illustrated embodiment. Thanks to this implementation, it is possible to avoid stopping movement of the tube T to allow the decompressing means 980 to operate. Instead, the decompressing means 980 can operate while the tube T moves. Preferably, the tube T is moved at a first speed and the decompressing means 980 are configured to move away from the channel 930 at the first speed. This ensures that the relative position of the coil spring with respect to the material of the tube is maintained, so that the pocket can be welded around the coil spring. In preferred embodiments, the decompressing means 980 can also be configured to pull the material of the tube as they move. Alternatively, or in addition, the tube can be pulled by further means placed downstream, in the moving direction of the tube such as, for instance, transverse welding means 960, which will be described more in details in the following.

[0153] Figures 9D, 9E and 9F illustrate the controlled expansion of the coil spring C2, in the Z direction, as the decompressing means 980 move away from the channel, in the negative X direction. Both movements are schematically illustrated by corresponding arrows.

[0154] As visible in figure 9G, the decompressing means 980 are configured to move back towards the channel 930 after having controllably reduced compression of the coil spring C2and / or after transverse welding, is completed, the operation of which will be described more in the detail in the following description. This allows the decompressing means 980 to be back in the loading position for the next cycle, for spring coil C3. During the return movement illustrated in figure 9G, the decompressing means 980 are configured to move the two plates 981, 982 towards each other as the decompressing means 980 move towards the channel 930. This allows the decompressing means 980 to be closed again when they reach the loading position for the next cycle. While in the description above it has been described that both plates 981, 982, move, it will be clear to those skilled in the art that similar results can be obtained by moving only one of the two plates, if preferred.

[0155] The device 900 further comprises transverse welding means 960, generally configured to receive the coil springs Ci-Cn from the decompressing means 980 and to weld the fabric tube T along a transverse welding WT, so as to obtain pocketed coil springs P1-P3 comprising the coil springs Ci-Cn. As indicated above, each pocket preferably comprises one, and even more preferably only one, coil spring.

[0156] In preferred embodiments, as visible in figures 9D-9F, the transverse welding means 960 are configured to move away from the channel 930 while welding the fabric tube T along the transverse welding WT. That is, during the phase in which the decompressing means move away from the channel 930, the transverse welding means 960 can be configured to move as well, so that their position with respect to the position of the decompressing means 980 is constant. The same comments made for the moving speed of the decompressing means is thus also applicable to the transverse welding means 960. In particular, the transverse welding means 960 are configured to move away from the channel 930 at the first speed of the tube T. Thanks to this configuration, it is possible to avoid stopping the movement of the tube T to allow the transverse welding means 960 to operate. Instead, they can operate while the tube T moves.

[0157] Preferably, the transverse welding means 960 operates transverse weld WT, on the side of the spring coil opposite to the position of the channel 930 or, in other words, on the downstream side of the spring coil, with reference to the movement direction of the spring coils. That is, with reference to the figures, on the left side of spring coil Ci. Still preferably, the other side of the pocket will be welded in the subsequent welding cycle. That is, the left side of spring coil Ci is welded while the subsequent spring coil C2is decompressed, and the right side of spring coil Ci, which corresponds the left side of spring coil C2, is welded while the subsequent spring coil C3 is decompressed, and so on. This is particularly advantageous since the fabric tube T on the left side of spring coil Ci is not subject to expansion, or generally to movement, during the decompression of spring coil C2, while the right side is.

[0158] As visible in figure 9G, and as already described for the decompressing means 980, the transverse welding means 960 are configured to move towards the channel 930 after having welded the fabric tube T along the transverse welding WT. This allows the transverse welding means 960 to be moved over the coil spring which has just been uncompressed, C2in the drawings, and start the next welding cycle. Thus, in some embodiments, the decompressing means 980 and the transverse welding means 960 are configured to move together, independently on the specific movement profiles. This is particularly advantageous as it allows those two elements to be mounted together on a single movable device, and requiring only one moving means.

[0159] Moreover, in preferred embodiments, as visible in figure 9A, the decompressing means 980 are configured to operate along a first longitudinal length Li of the fabric tube T. Similarly, the transverse welding means 960 are configured to operate along a second longitudinal length l_2of the fabric tube T. Preferably, the first longitudinal length Li and the second longitudinal length l_2have substantially the same length. Here, the term substantially can be understood to mean that the difference in the length is less than 15%, preferably less than 10%, of the width of a pocket P. The width of a pocket can be defined as the size of the pocket in a direction opposite to the direction of compression of the coil spring. With reference to the illustrated embodiment, the width of the pocket is measured along direction X. This advantageously allows synchronous movement of the decompressing means 980 and of the transverse welding means 960.

[0160] In the embodiments illustrated in figures 9A-9G, a plurality of coil springs is placed in the channel 930, waiting to be processed. In this implementation, the channel operates as a buffer, where the insertion of a new coil spring on the entrance side, right in the figures, pushes one coil spring outside on the exit, left in the figures. The present invention is however not limited thereto and it will be possible to also operate with at most one coil spring being in the channel 930 at any given time. This can be achieved, for instance, by configuring pushing means PM, described with reference to figure 1C, to push one spring from the plates 121a, 121b, through the channel 930, and into the plates 981, 982. In both cases, the pushing means PM are preferably configured to push the coil springs at the speed of movement of the fabric tube.

[0161] It has thus been described how coil springs can be decompressed in a controlled manner, positioned into the fabric tube and transversally welded without interrupting the continuous movement of the fabric tube T.

[0162] While various embodiments have been described above, each with one or more features, it will be clear to those skilled in the art that not all features described in conjunction with an embodiment are strictly necessary for the implementation of the given embodiment. It will be further clear that the combination of one or more features from a first embodiment with one or more features from a second embodiment can result in further embodiments of the invention, within the meaning of the claims. Reference numerals

[0163] 100: device for compression of coil springs

[0164] 110: conveying means

[0165] 111: holding means

[0166] 120: compressing means

[0167] 121a, 121b: compressing plate

[0168] 130: channel

[0169] 131, 132: plate

[0170] Ci-C5: coil springs

[0171] CW: channel width

[0172] Pi, P2: path

[0173] LL: loading location

[0174] UL: unloading location

[0175] PM: pushing means

[0176] 220: compressing means

[0177] 221a, 221b: compressing plate

[0178] 222a, 222b: conveying means

[0179] 223: guiding rail

[0180] 224: conveyor belt

[0181] 225a, 225b: connection

[0182] 300: device for compression of coil springs

[0183] 320: compressing means

[0184] 326: conveying means 327: actuator

[0185] 400: device for longitudinal welding

[0186] 410: anvil

[0187] 411: welding extremity

[0188] 420: moving means

[0189] 430: sonotrode

[0190] 440: pulling means

[0191] AR: rotation axis

[0192] D: distance

[0193] FL: folding line

[0194] FM: folding means

[0195] FS: fabric sheet

[0196] FFS: folded fabric sheet

[0197] WL: longitudinal weld

[0198] 500: device for longitudinal welding

[0199] 540, 550a, 550b: moving means

[0200] 610a, 610b, 610c: anvil

[0201] 700: device for coil removal

[0202] 711: holding means

[0203] 712, 713: ends

[0204] 720: actuating means 710: conveying means

[0205] C: coil spring

[0206] CS: cutting section

[0207] CO: coiler

[0208] 800: device for coil removal

[0209] 840: confining means

[0210] 850: actuating means

[0211] C: coil spring

[0212] CS: cutting section

[0213] CO: coiler

[0214] 900: device for pocketing of coil springs

[0215] 930: channel

[0216] 933: end of channel

[0217] 960: transverse welding means

[0218] 970: longitudinal welding means

[0219] 980: decompressing means

[0220] 981, 982: plates

[0221] Ci-Cn: coil spring

[0222] FS: fabric sheet

[0223] Li, L2: length

[0224] WL: longitudinal welding

[0225] P1-P3: pocketed coil springs T: fabric tube

[0226] WT: transverse welding

Claims

Claims1. Device (100, 300) for compression of coil springs (C1-C5), the device (100, 300) comprising: first conveying means (110) configured to convey the coil springs (C1-C5) along a first path (Pi) at a first speed, wherein the first conveying means (110) comprise a plurality of holding means (111), each of holding means (111) configured to hold a respective coil spring (C1-C5), compressing means (120, 220, 320) configured to compress the coil springs (C1-C5) as they are conveyed along the first path (Pi), wherein the compressing means (120, 220, 320) comprise two compressing plates (121a, 121b; 221a, 221b), wherein the compressing means (120, 220, 320) are configured to move the compressing plates (121a, 121b; 221a, 221b) toward each other so as to compress at least one coil spring (C1-C5) between the compressing plates (121a, 121b; 221a, 221b), characterized in that the compressing means (120, 220, 320) is further configured to move the compressing plates (121a, 121b; 221a, 221b) along the first path (Pi) at the first speed.

2. The device (100, 300) according to claim 1 wherein, the compressing means (120, 220, 320) are configured to position two compressing plates (121a, 121b; 221a, 221b) at a predetermined angle with respect to each other as the compressing plates (121a, 121b; 221a, 221b) are moved along the first path (Pi).

3. The device (100, 300) according to claim 1 or 2 further comprising a channel (130) configured to receive the coil springs (C1-C5) in a compressed state.

4. The device (100, 300) according to any previous claim, wherein the compressing means (120, 220, 320) are configured to remove a coil spring (C5) from the respective holding means (111) in a at least partially compressed state.

5. The device (100, 300) according to any previous claim wherein the first conveying means (110) is any of a conveyor belt, a conveyor chain, a rotating element.

6. The device (100, 300) according to any previous claim wherein one or more of the holding means (111) comprises any of a magnet, pinching means, carrying means.

7. The device (100) according to any previous claim, wherein the compressing means (220) further comprise two second conveying means (222a, 222b) configured to move the compressing plates (221a, 221b) toward each other.

8. The device (100) according to claim 7, wherein the two second conveying means (222a, 222b) are configured to move at a speed higher than the first speed.

9. The device (100) according to claim 7 or 8, wherein each of the two second conveying means (222a, 222b) comprises a guiding rail (223) and a conveyor belt (224).

10. The device (100) according to claim 9, wherein any of the compressing plates (221a, 221b) has a first connection (225a) to the respective guiding rail (223) and a second connection (225b) to the respective conveyor belt (224).

11. The device (100) according to claim 10, wherein any of the first connection (225a) and of the second connection (225b) allows rotation between the two connected elements.

12. The device (100) according to any of claims 7 to 11, wherein the two second conveying means (222a, 222b) rotate in opposite directions.

13. The device (100) according to any of claims 7 to 12, wherein the two second conveying means (222a, 222b) extend further than the first conveying means (110) in a direction along the first path (Pi).

14. The device (300) according to any of claims 1 to 6, wherein the compressing means (320) further comprise a third conveying means (326) configured to move an actuator (327) carrying the compressing plates (121a, 121b).

15. Device (400, 500) for longitudinal welding of a folded fabric sheet (MF) for coil spring pockets, the device (400, 500) comprising: a sonotrode (430), an anvil (410, 610a, 610b, 610c) configured to rotate around a rotation axis (AR).

16. The device (400, 500) according to claim 15, wherein the rotation axis (AR) is substantially parallel to a plane interpolating the folded fabric sheet (MF), and / or is substantially perpendicular to a plane interpolating the anvil (410, 610a, 610b, 610c), and / or is substantially perpendicular to a direction connecting a center of rotation of the anvil (410, 610a, 610b, 610c) and the sonotrode (430).

17. The device (400, 500) according to claim 15 or 16, wherein the folded fabric sheet (MF) is moved through the device (400, 500) at a first speed, and the anvil (410, 610a, 610b, 610c) comprises a welding extremity (411), the anvil (410, 610a, 610b, 610c) is configured to rotate so as to move the welding extremity (411) with the first speed.

18. The device (400, 500) according to claim 17, whereinthe folded fabric sheet (MF) is moved through the device (400, 500) at the first speed by pulling means (440).

19. The device (400, 500) according to any of claims 15 to 18, wherein the anvil (410, 610a, 610b, 610c) is circular.

20. The device (400, 500) according to claim 19, wherein the anvil (410, 610a, 610b, 610c) has a diameter larger than 5cm, preferably larger than 9Cm and / or smaller than 30cm, preferably smaller than 15cm.

21. The device (500) according to any of claims 15 to 20, further comprising first moving means (540) configured to move the anvil (410, 610a, 610b, 610c) and the sonotrode (430) together, along the rotation axis (AR).

22. The device (500) according to any of claims 15 to 21, further comprising second moving means (550a, 550b) configured to move the anvil (410, 610a, 610b, 610c) with respect to the sonotrode (430), or the sonotrode (430) with respect to the anvil (410, 610a, 610b, 610c), along a direction perpendicular the rotation axis (AR).

23. The device (400, 500) according to any of claims 15 to 22, wherein the anvil (610a, 610c) comprises a welding extremity (411), and the welding extremity (411) has a flat surface.

24. The device (400, 500) according to any of claims 15 to 22, wherein the anvil (610b) comprises a welding extremity (411), and the welding extremity (411) has a toothed surface.

25. The device (400, 500) according to any of claims 15 to 24, wherein the anvil (610c) comprises a welding extremity (411), and the welding extremity (411) has a surface with an angle (O) with respect to the rotation axis (AR).

26. The device (400, 500) according to claim 25, wherein the angle (O) is larger than 0 degrees, preferably larger than 10 degrees, and / or the angle (O) is smaller than 60 degrees, preferably smaller than 30 degrees.

27. Device (700, 800) for removing coil springs (C) from a cutting section (CS) of a coiler (CO), the device (700, 800) comprising: a plurality of holding means (711), each of the holding means (711) being configured to hold a respective coil spring (C) outputted by the cutting section (CS), conveying means (710) configured to convey the holding means (711), first actuating means (720) configured to position one of the holding means (711) so as to be substantially parallel with a coil spring (C) at a time of cutting of the coil spring (C) by the cutting section (CS).

28. The device (700, 800) according to claim 27, wherein one or more of the holding means (711) comprises any of a magnet, pinching means, carrying means.

29. The device (700, 800) according to claim 27 or 28, wherein one or more of the holding means (711) comprises a first end (712) and a second end (713), opposite the first end along a direction of elongation of the holding mean (711), the second end (713) is hingedly connected to the conveying means (710), the first actuating means (720) are configured to act on the first end (712).

30. The device (700, 800) according to claims 29, whereinthe first actuating means (720) are configured to lift the first end (712) before the time of cutting of the coil spring (C) by the cutting section (CS), and / or the first actuating means (720) are configured to lower the first end (712) after the time of cutting of the coil spring (C) by the cutting section (CS).

31. The device (700, 800) according to any of claims 27 to 30, wherein one or more of the holding means (711) is configured to have a length at least equal to a length (CL) of the of coil springs (C).

32. The device (800) according to any of claims 27 to 31, further comprising confining means (840) configured to limit at least partially confine movement of the coil spring (C) at the time of cutting of the coil spring (C) by the cutting section (CS), and second actuating means (850) configured to position the confining means (840).

33. The device (800) according to claim 32, wherein the second actuating means (850) are configured to move the confining means (840) towards the coil spring (C) before the time of cutting of the coil spring (C) by the cutting section (CS), and / or the second actuating means (850) are configured to move the confining means (840) away from the coil spring (C) after the time of cutting of the coil spring (C) by the cutting section (CS).

34. The device (800) according to claim 32 or 33, wherein the confining means (840) are configured to allow movement of the coil spring (C) in the direction of a holding means (711) configured to hold the coil spring (C).

35. Device (900) for pocketing coil springs (Ci-Cn) into pocketed coil springs (P1-P3), the device (900) comprising: a channel (930) configured to guide the coil springs (Ci-Cn) in a compressed state,longitudinal welding means (970) configured to weld two extremities of a folded fabric sheet (FS) along a longitudinal welding (WL) to obtain a fabric tube (T), wherein the longitudinal welding means (970) are configured such that the fabric tube (T) surrounds least one end (933) of the channel (930), decompressing means (980) configured to receive the coil springs (Ci-Cn) from the channel (930) in a compressed state and controllably reduce compression of the coil springs (Ci-Cn), transverse welding means (960) configured to receive the coil springs (Ci-Cn) from the decompressing means (980) and to weld the fabric tube (T) along a transverse welding (WT) to obtain pocketed coil springs (P1-P3) comprising the coil springs (Ci-Cn).

36. Device (900) according to claim 35, wherein the decompressing means (980) comprise two plates (981, 982) configured to hold the extremities of the coil springs (Ci-Cn).

37. Device (900) according to any of claims 35-36, wherein the decompressing means (980) are configured to controllably reducing compression of the springs (Ci-Cn) inside of the fabric tube (T).

38. Device (900) according to any of claims 35-37, wherein the decompressing means (980) are configured to move away from the channel (930) while controllably reducing compression of the coil springs (Ci-Cn).

39. Device (900) according to claim 38, wherein the tube (T) is moved at a first speed, the decompressing means (980) are configured to move away from the channel (930) at the first speed.

40. Device (900) according to any of claims 35-39, wherein the decompressing means (980) are configured to move towards the channel (930) after having controllably reduced compression of the coil springs (Ci-Cn).

41. Device (900) according to claim 36 and 40, wherein the decompressing means (980) are configured to move the two plates (981, 982) towards each other as the decompressing means (980) move towards the channel (930).

42. Device (900) according to any of claims 35-41, wherein the transverse welding means (960) are configured to move away from the channel (930) while welding the fabric tube (T) along the transverse welding (WT).

43. Device (900) according to claim 42, wherein the tube (T) is moved at a first speed, the transverse welding means (960) are configured to move away from the channel (930) at the first speed.

44. Device (900) according to any of claims 35-43, wherein the transverse welding means (960) are configured to move towards the channel (930) after having welded the fabric tube (T) along the transverse welding (WT).

45. Device (900) according to any of claims 35-44, wherein the decompressing means (980) and the transverse welding means (960) are configured to move together.

46. Device (900) according to any previous claim, wherein the decompressing means (980) are configured to operate along a first longitudinal length (Li) of the fabric tube (T), the transverse welding means (960) are configured to operate along a second longitudinal length (Lj) of the fabric tube (T),the first longitudinal length (Li) and the second longitudinal length (L2) have substantially the same length.

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