Filament feeder

Abstract

A filament feeder (1) for a fused filament fabrication printer, comprising a feeder body (2) comprising a channel (3) for guiding a filament (F) therethrough. First and second driven pinch rollers (4, 5) are arranged on opposite sides of the channel (3) for pinch engagement with the filament (F), wherein the first pinch roller (4) is rotatably arranged about a first roller axis (4a) and the second pinch roller (5) is rotatably arranged about a second roller axis (5a). The feeder comprises a first drive gear (6) for driving the first pinch roller (4), the first drive gear being rotatably arranged about the first roller axis (4a), a second drive gear (7) for driving the second pinch roller (5), the second drive gear being rotatably arranged about the second roller axis (5a), and a suspension system (S) for suspending the first and second pinch rollers (4, 5) and the first and second drive gears (6, 7). The suspension system (S) is arranged to allow lateral movement of the first and second pinch rollers (4, 5) relative to the channel (3) to provide a variable distance (D+ΔD) between the first and second roller axes (4a, 5a).

Description

TECHNICAL FIELD

[0001] The present invention relates to a filament feeder for a fused filament fabrication (FFF) printer. The present invention also relates to a print head comprising the filament feeder, and to a fused filament printer comprising the filament feeder. BACKGROUND

[0002] International application WO 2008 / 100467 Al discloses a filament feeding assembly comprising a gear system with two rotatable drive rollers that grip and pull a filament from a filament tube. The filament feeding assembly comprises a support plate to which a feeder module is fixed, and the feeder module comprises a channel through which the filament is guided towards the two drive rollers. One of the two drive rollers can be pivotally fixed to the support plate in order to provide a mechanism for self-correction of the filament slide between the two drive rollers.

[0003] Prior art filament feeding assemblies such as the one described above do not allow the two drive rollers to remain symmetrically arranged or centered with respect to the feeding channel when the distance between the two rotatable rollers changes. This results in the feeding channel having to be wider in order to allow the filament to be laterally off-center within the feeding channel when the distance between the two rollers changes. SUMMARY

[0004] The present invention seeks to provide a filament feeder that solves at least one of the above-mentioned problems.

[0005] According to a first aspect of the present invention, there is provided a filament feeder comprising a feeder body comprising a channel for guiding a filament therethrough. A first driven pinch roller and a second driven pinch roller are arranged on opposite sides of the channel for pinch engagement with the filament, wherein the first pinch roller is rotatably arranged about a first roller axis, and wherein the second pinch roller is rotatably arranged about a second roller axis. A first drive gear is provided for driving the first pinch roller, wherein the first drive gear is rotatably arranged about the first roller axis. A second drive gear is provided for driving the second pinch roller, wherein the second drive gear is rotatably arranged about the second roller axis. The filament feeder further comprises a suspension system for suspending the first and second pinch rollers and the first and second drive gears, wherein the suspension system is arranged to allow lateral movement of the first and second pinch rollers with respect to the channel to provide a variable distance between the first and second roller axes.

[0006] According to the present invention, the suspension system S allows both the first driven pinch roller and the second driven pinch roller to move laterally relative to the channel to ensure that the first pinch roller and the second pinch roller remain in a symmetrical arrangement relative to the channel as the width or size of the filament between the first pinch roller and the second pinch roller increases. By maintaining the symmetrical position of the first pinch roller and the second pinch roller relative to the channel, bending or kinking of the filament as it is drawn through the filament supply by the first pinch roller and the second pinch roller is avoided. That is, the laterally movable first pinch roller and the second pinch roller allow the filament to remain centered within the channel, thereby avoiding bending of the filament.

[0007] In one embodiment, wherein the first roller axis is arranged at a first channel distance relative to the central axis of the channel, and wherein the second roller axis is arranged at a second channel distance relative to the central axis of the channel, and wherein the first channel distance and the second channel distance are variable over a first lateral displacement and a second lateral displacement, respectively, which are substantially equal. This allows for symmetrical pinching of a filament F that becomes wider or narrower.

[0008] In one embodiment, the suspension system comprises a resilient suspension member arranged to resiliently bias the first pinch roller and the second pinch roller towards the filament. This allows for a consistent and symmetrical pushing force exerted by the two pinch rollers on the filament for changing the width of the filament.

[0009] In one embodiment, the suspension system comprises a first support plate and a second support plate mounted on opposite sides of the supply body, wherein the first support plate comprises a first support portion and a second support portion, and wherein the second support plate comprises a third support portion and a fourth support portion; wherein the first pinch roller and the second pinch roller comprise a first roller shaft and a second roller shaft, respectively, and wherein the first roller shaft is suspended by the first support portion and the third support portion, and wherein the second roller shaft is suspended by the second support portion and the fourth support portion, and wherein the first support portion, the second support portion, the third support portion and the fourth support portion are laterally movable relative to the channel. The first support portion, the second support portion, the third support portion and the fourth support portion allow for a simple swing arm arrangement to provide symmetrical movement of the first pinch roller and the second pinch roller relative to the channel.

[0010] In one embodiment, the first support portion, the second support portion, the third support portion and the fourth support portion are pivotally arranged in respective planes of the first support plate and the second support plate, thereby minimizing the thickness of the entire supply.

[0011] In one embodiment, the first support plate includes a first pivot portion and a second pivot portion, and wherein the second support plate includes a third pivot portion and a fourth pivot portion, wherein the first pivot portion and the second pivot portion pivotally connect the first support plate to the first support portion and the second support portion, and wherein the third pivot portion and the fourth pivot portion pivotally connect the second support plate to the third support portion and the fourth support portion. This provides an efficient pivot mechanism to allow lateral movement of the first and second clamping rollers.

[0012] In one embodiment, the first support plate, the first and second support portions, and the first and second pivot portions are formed as a single piece, and wherein the second support plate, the third and fourth support portions, and the third and fourth pivot portions are formed as a single piece. This allows for a simpler and more cost-effective design of the filament feeder.

[0013] In one embodiment, the first support plate includes a first transversely elastic biasing portion connecting the first support portion and the second support portion, and the second support plate includes a second transversely elastic biasing portion connecting the third support portion and the fourth support portion. This embodiment enables elastic engagement of the first and second clamping rollers with the filament F.

[0014] In one embodiment, the first biasing portion and the first and second support portions are formed as a single piece, and wherein the second biasing portion and the third and fourth support portions are formed as a single piece. This provides sufficient structural integrity to support the first and second clamping rollers while providing sufficient resilience to allow lateral movement of the first and second clamping rollers.

[0015] In one embodiment, the first support portion includes a first lateral inward protrusion, and the second support portion includes a second lateral inward protrusion, wherein the suspension system is configured to allow abutment of the first and second lateral inward protrusions when the variable distance reaches a lower limit. By means of such inward protrusions, the variable distance can be prevented from becoming too small.

[0016] In one embodiment, the third support portion includes a third lateral inward protrusion, and the fourth support portion includes a fourth lateral inward protrusion, wherein the suspension system is configured to allow the third and fourth lateral inward protrusions to abut when the variable distance reaches a lower limit. Such inward protrusions can prevent the variable distance from becoming too small.

[0017] In one embodiment, the first support portion includes a first lateral outward protrusion, and the second support portion includes a second lateral outward protrusion, and the suspension system S is configured to allow the first and second lateral outward protrusions to abut against opposing edges of the first support plate or the feeder body when the variable distance reaches an upper limit. Such outward protrusions can prevent the variable distance from becoming too large.

[0018] In one embodiment, the third support portion includes a third laterally outward protrusion, and the fourth support portion includes a fourth laterally outward protrusion, and the suspension system is configured to allow the third and fourth laterally outward protrusions to abut against opposing edges of the second support plate or the feeder body when the variable distance reaches an upper limit. Such outward protrusions prevent the variable distance from becoming too large.

[0019] In one embodiment, the first support plate includes an adjustable first lever portion having a first lever end and a second lever end, the first lever end being pivotally connected to the feeder body at a first lever pivot point, and wherein the second support plate includes an adjustable second lever portion having a third lever end and a fourth lever end, the third lever end being pivotally connected to the feeder body at a second lever pivot point, wherein the first lever portion is connected to the first support portion and the second support portion between the first lever end and the second lever end for positioning the first portion and the second portion laterally relative to the channel, and wherein the second lever portion is connected to the third support portion and the fourth support portion between the third lever end and the fourth lever end for positioning the third support portion and the fourth support portion laterally relative to the channel. This causes the first lever portion 30 and the second lever portion 31 to pivot and thereby cause the first, second, third and fourth support portions, in particular the first and second clamping rollers, to move laterally relative to the channel.

[0020] In one embodiment, the first support plate comprises a first pivot portion and a second pivot portion, and wherein the second support plate comprises a third pivot portion and a fourth pivot portion, wherein the first pivot portion and the second pivot portion pivotally connect the first support portion and the second support portion and the first lever portion, respectively, and wherein the third pivot portion and the fourth pivot portion pivotally connect the third support portion and the fourth support portion and the second lever portion, respectively. In this embodiment, the first pivot portion, the second pivot portion, the third pivot portion and the fourth pivot portion provide a symmetrical arrangement of the first support portion, the second support portion, the third support portion and the fourth support portion relative to the channel, thereby providing a positive connection between the first lever portion and the second lever portion and the first support portion, the second support portion, the third support portion and the fourth support portion.

[0021] In one embodiment, the first lever portion, the first and second pivot portions, and the first and second support portions are formed as a single piece, and wherein the second lever portion, the third and fourth pivot portions, and the third and fourth support portions are formed as a single piece. This embodiment facilitates cost-effective manufacturing and provides a thin suspension system S.

[0022] In one embodiment, the second lever end and the fourth lever end are resiliently connected to the feeder body to obtain biased engagement of the first and second pinch rollers toward the channel, ie, the filament.

[0023] In one embodiment, the first drive gear and the first clamping roller form a single piece, and wherein the second drive gear and the second clamping roller form a single piece. The first clamping roller is provided with a circumferentially arranged annular first groove, and wherein the second clamping roller is provided with a circumferentially arranged annular second groove. The first groove and the second groove are configured to engage with the filament F in a clamping manner, and this embodiment provides an annular groove, for example for evenly distributed clamping on a round filament F. In addition, a gear meshing is provided on both sides of the groove between the first and drive gears, so that the tooth forces applied to the first drive gear are arranged symmetrically with respect to the first groove, and the tooth forces applied to the second drive gear are arranged symmetrically with respect to the second groove. As a result, the first roller and the second roller are evenly loaded along their length.

[0024] In an alternative embodiment, the first drive gear and the first clamping roller are formed into a single piece having a circumferentially arranged V-shaped first groove, wherein the second drive gear and the second clamping roller are formed into a single piece having a circumferentially arranged V-shaped second groove, wherein the first groove and the second groove are configured for clamping engagement with the filament. When necessary, the first V-shaped groove and the second V-shaped groove can allow a stronger pulling force to be applied to the filament.

[0025] In one embodiment, the first groove and the second groove may each include a flat bottom provided with a raised surface texture configured to increase grip of the filament.

[0026] In one embodiment, the filament feeder includes a driven worm gear in meshing engagement with the first drive gear or the second drive gear. The worm gear allows for a compact design and can be arranged at various angles while maintaining meshing engagement with the first drive gear or the second drive gear.

[0027] In a second aspect of the present invention, there is provided a print head comprising a filament feeder as described above.

[0028] In a third aspect of the present invention, there is provided an FFF printer comprising the filament feeder as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be discussed in more detail below with reference to the accompanying drawings, in which

[0030] Figure 1 shows a perspective view of a feeder according to an embodiment of the present invention;

[0031] Figure 2 Shown Figure 1 A perspective view of a feeder body according to an embodiment of the present invention;

[0032] Figure 3 and Figure 4 showing opposing side views of a filament feeder apparatus according to an embodiment of the present invention;

[0033] Figure 5 shows a cross-section of a filament feeder device according to an embodiment of the present invention;

[0034] Figure 6 shows a perspective view of a feeder according to one embodiment;

[0035] Figure 7A and Figure 7B showing a side view of an opposite side of an adjustable filament feeder arrangement according to an embodiment of the present invention;

[0036] Figure 8 shows a perspective view of two clamping rollers according to an embodiment of the present invention;

[0037] Figure 9 shows a top view of two clamping rollers according to another embodiment of the present invention;

[0038] Figure 10 shows a top view of two clamping rollers according to a third embodiment of the present invention;

[0039] Figure 11 shows a top view of two clamping rollers according to a fourth embodiment of the present invention;

[0040] Figure 12 shows a main drive gear according to an embodiment of the present invention;

[0041] Figure 13 An FFF printer having a print head including a filament feeder is schematically shown. DETAILED DESCRIPTION

[0042] exist Figure 1 , a perspective view of a filament feeder according to an embodiment of the present invention is shown, wherein Figure 2 Shown Figure 1A perspective view of a feeder body of an embodiment of the present invention. As shown in the figure, the filament feeder 1 includes a feeder body 2 having a channel 3 for guiding the filament F therethrough. In this embodiment, the feeder body 2 is a generally block-shaped body having a plurality of holes, one of which constitutes the channel 3, while the other two holes provide space for clamping rollers and gears. In the following, the feeder body 2 is also referred to as the feeder block 2, but it should be noted that the present invention is not limited to the use of a block-shaped body, and other forms are conceivable depending on the application. As Figure 1 As shown, the first driven clamping roller 4 and the second driven clamping roller 5 are arranged on opposite sides of the channel 3 for clamping engagement with the filament F, wherein the first clamping roller 4 is rotatably arranged around the first roller axis 4a and the second clamping roller 5 is rotatably arranged around the second roller axis 5a.

[0043] A first drive gear 6 is then provided to drive the first pinch roller 4, and a second drive gear 7 is provided to drive the second pinch roller 5. The first drive gear 6 and the second drive gear 7 are rotatably arranged about the first roller axis 4a and the second roller axis 5a, respectively.

[0044] It should be noted that the first clamping roller 4 Figure 1 is not directly visible in the diagram, as it is located behind the first drive gear 6. However, the position of the first clamping roller 4 can be seen from Figure 1 As can be inferred from the second nip roller 5 clearly visible in the drawing, the first nip roller 4 is arranged opposite the second nip roller 5 on the opposite side of the channel 3. In the feeder block 2, openings 70 are arranged on both sides of the feeder 1. Debris from the filaments F can be removed from the feeder 1 via these openings 70.

[0045] The filament feeder 1 further comprises a suspension system S for suspending the first clamping roller 4 and the second clamping roller 5 and the first drive gear 6 and the second drive gear 7, wherein the suspension system S is arranged to allow lateral movement of the first clamping roller 4 and the second clamping roller 5 relative to the channel 3, for example substantially symmetrical lateral movement, so as to provide a variable distance D+ΔD between the first roller axis 4a and the second roller axis 5a.

[0046] According to the present invention, the suspension system S allows the first and second driven nip rollers 4, 5 to move laterally relative to the channel 3, ensuring that the first and second nip rollers 4, 5 maintain a symmetrical arrangement relative to the channel 3 as the width or size of the filament F between the first and second nip rollers 4, 5 increases. By maintaining the symmetrical position of the first and second nip rollers 4, 5 relative to the channel 3, bending or kinking of the filament F is avoided as it is pulled through the filament feeder 1 by the first and second nip rollers 4, 5. That is, the laterally movable first and second nip rollers 4, 5 allow the filament to remain centered within the channel 3, thereby avoiding bending of the filament F. This is particularly advantageous when using filament diameters of 1.75 mm or less, where the risk of bending is considerable.

[0047] In an advantageous embodiment, the suspension system S is adapted to elastically bias the first and second clamping rollers 4, 5 to the filament F, thereby allowing a consistent and symmetrical thrust exerted by the two clamping rollers 4, 5 on the filament F for varying widths of the filament F. In an exemplary embodiment, the suspension system S may comprise a first movable support portion 10 and a second movable support portion 11 for supporting the first and second clamping rollers 4, 5, respectively, wherein the first support portion 10 and the second support portion 11 are arranged to elastically bias the first and second clamping rollers 4, 5 to the filament F.

[0048] Note that the first and second pinch rollers 4 and 5 may include a first roller shaft 14 and a second roller shaft 15 , respectively, and wherein the first roller shaft 14 is suspended from the first support portion 10 , and wherein the second roller shaft 15 is suspended from the second support portion 11 .

[0049] In the illustrated embodiment, the first support portions 10, 11 can be pivotally connected to the feeder block 2 at a first pivot point p1, and wherein the second support portion 11 can be pivotally connected to the feeder block 2 at a second pivot point p2. The pivot points p1, p2 are relatively thin portions of the support plate 8 that are flexible in the plane of the support plate 8. In this embodiment, when the first support portion 10 and the second support portion 11 move about the first pivot point p1 and the second pivot point p2, a lateral displacement of the first and second clamping rollers 4, 5 results, thereby generating a variable distance D+ΔD between the first roller axis 4a and the second roller axis 5a.

[0050] In the exemplary embodiment shown, the first support portion 10 and the second support portion 11 can be considered as first and second swing arms 10 and 11, respectively, each of which includes a first pivot end 10a and a second pivot end 11a, respectively, which are connected to the feeder block 2 at a first pivot point p1 and a second pivot point p2, respectively. Each of the first and second swing arms 10 and 11 then includes a first roller end 10b and a second roller end 11b, respectively, to support the first and second clamping rollers 4 and 5.

[0051] A spring-loaded biasing member B may be connected between the first support portion 10 and the second support portion 11, i.e., between the first swing arm 10 and the second swing arm 11, as seen in this embodiment. The biasing member B is configured to elastically pivot the swing arms 10, 11 so that the first and second clamping rollers 4, 5 are elastically urged toward the channel 3, i.e., the filament F.

[0052] Figure 2 Shown Figure 1 A perspective view of a feeder block 2 of an embodiment of the present invention. As shown in the figure, the feeder block 2 includes a channel 3 through which the filament F extends when the filament feeder 1 is operated. The feeder block 2 includes a first through hole B1 to allow the first clamping roller 4 to extend therethrough, and a second through hole B2 is provided to allow the second clamping roller 5 to extend therethrough. The first and second through holes B1, B2 each have a sufficiently large lateral width W1, W2 to allow the first and second clamping rollers 4, 5 to move in the lateral direction to achieve a variable distance D+ΔD between the first and second roller axes 4a, 5a. In an advantageous embodiment, the first and second holes B1, B2 can overlap in such a way that a cutout 2a is obtained in the feeder block 2 so that the first and second drive gears 6, 7 can be arranged in the first and second holes B1, B2, respectively, while also being able to engage with each other. As shown in the figure, the cutout 2a is aligned with the center axis C of the channel 3.

[0053] In one embodiment, for strength and durability, the feeder block 2 can be made of a metal such as aluminum to minimize weight while maintaining sufficient strength. Of course, in alternative embodiments, the feeder block 2 can be made of a durable plastic material to minimize weight, perhaps a fiber-reinforced plastic material for improved strength. In an exemplary embodiment, the feeder block 2 can have a length (L) between 20-40 mm, a height (H) between 10-30 mm, and a thickness (T) between 5-20 mm.

[0054] exist Figure 3 and Figure 4 , there is shown an opposite side view of a filament feeder 1 according to an embodiment of the present invention, wherein Figure 5 Shown as Figure 3 and Figure 4FIG2 is a cross-section of a filament feeder 1 shown in FIG2 . In the embodiment shown, the first roller axis 4a is arranged at a first channel distance d1 relative to the central axis C of the channel 3, and wherein the second roller axis 5a is arranged at a second channel distance d2 relative to the central axis C of the channel, and wherein the first and second channel distances (d1, d2) are variable over substantially equal first and second lateral displacements Δd1 and Δd2, respectively. Here, the first and second lateral displacements Δd1, Δd2 can each be positive or negative to allow symmetrical clamping of the filament F that becomes wider or narrower.

[0055] It is important to note that in Figure 5 In the cross-section shown in FIG, the first and second drive gears 6 and 7 can be seen to be directly meshing, as illustrated by the meshing teeth t1 and t2. Furthermore, this meshing engagement between the first and second drive gears 6 and 7 is maintained for the variable distance D+ΔD between the first and second roller axes 4a and 5a. That is, the first and second lateral displacements Δd1 and Δd2 remain sufficiently small so that the teeth t1 and t2 remain engaged. Having direct engagement between the first and second drive gears 6 and 7 simplifies driving the first and second pinch rollers 4 and 5 in opposite directions.

[0056] The suspension system S as described above can be implemented in various ways. For example, Figure 3 and Figure 4 In the embodiment shown, the suspension system includes first and second support plates 8, 9 mounted on opposite sides of the feeder block 2. The first support plate 8 includes first and second support portions 10, 11, and wherein the second support plate 9 includes third and fourth support portions 12, 13. The first and second nip rollers 4, 5 each include first and second roller shafts 14, 15, respectively, and wherein the first roller shaft 14 is suspended from the first and third support portions 10, 12, and wherein the second roller shaft 15 is suspended from the second and fourth support portions 11, 13. To achieve lateral movability of the first and second nip rollers 4, 5, the first, second, third, and fourth support portions 10, 11, 12, 13 are laterally movable relative to the channel 3.

[0057] The first, second, third and fourth support portions 10 , 11 , 12 , 13 may be pivotally arranged in respective planes of the first and second support plates 8 , 9 , eg to minimize the thickness T of the feeder block 2 .

[0058] In one embodiment, the first support plate 8 includes first and second pivot portions 16, 17, and the second support plate 9 includes third and fourth pivot portions 18, 19, wherein the first and second pivot portions 16, 17 pivotally connect the first support plate 8 to the first and second support portions 10, 11, respectively. The third and fourth pivot portions 18, 19 pivotally connect the second support plate 9 to the third and fourth support portions 12, 13, respectively. In this embodiment, an effective pivot mechanism is implemented to allow lateral movement of the first and second clamping rollers 4, 5.

[0059] As depicted, the first and second support portions 10, 11 may be pivotally connected to the feeder block 2, i.e., the first support plate 8, via first and second pivot points p1, p2, respectively. The third and fourth support portions 12, 13 may be pivotally connected to the feeder block 2, i.e., the second support plate 9, via third and fourth pivot points p3, p5, respectively.

[0060] In an advantageous embodiment, the first support plate 8, the first and second support portions 10, 11 and the first and second pivot portions 16, 17 form a single piece, and wherein the second support plate 9, the third and fourth support portions 12, 13 and the third and fourth pivot portions 18, 19 form a single piece.

[0061] Having these single-piece components allows for a simpler and cost-effective design for the filament feeder 1, for example, the first support plate 8 and the second support plate 9 can each be made of a sheet-based material (e.g., sheet metal), which is then stamped so that the first support portion 10, the second support portion 11, the third support portion 12, and the fourth support portion 13 and the first pivot portion 16, the second pivot portion 17, the third pivot portion 18, and the fourth pivot portion 19 are integrally formed. Here, each of the first, second, third, and fourth pivot portions 16, 17, 18, 19 can be regarded as a sufficiently thin swing arm to allow elastic behavior at the first, second, third, and fourth pivot points p1, p2, p3, p4. To increase the elastic behavior, each of the first, second, third, and fourth pivot portions 16, 17, 18, 19 can include two opposing narrow ends for obtaining the associated pivot points p1, p2, p3, p4.

[0062] In order to achieve elastic engagement of the first and second clamping rollers 4, 5 with the filament F, an embodiment is provided in which the first support plate 8 includes a transversely elastic first biasing portion 20 connecting the first and second support portions 10, 11, and in which the second support plate 9 includes a transversely elastic second biasing portion 21 connecting the third and fourth support portions 12, 13. Here, the first biasing portion 20 connects the first and second support portions 10, 11 in an elastic manner, and the second biasing portion 21 connects the third and fourth support portions 12, 13 in an elastic manner, so that a transverse movement of the first and second clamping rollers 4, 5 is possible, and in which the first and second clamping rollers 4, 5 are biased towards the channel 3, i.e. towards the filament F.

[0063] exist Figure 3 and Figure 4 In an exemplary embodiment, the first biasing portion 20 may include a U-shaped or arcuate piece for providing a resilient connection between the first and second support portions 10, 11. Similarly, the second biasing portion 21 may include a U-shaped or arcuate piece for providing a resilient connection between the third and fourth support portions 10, 11.

[0064] In an advantageous embodiment, the first biasing portion 20 is formed as a single piece with the first and second support portions 10, 11, and wherein the second biasing portion 21 is formed as a single piece with the third and fourth support portions 12, 13. This provides sufficient structural integrity to support the first and second clamping rollers 4, 5, while providing sufficient resilience to allow lateral movement of the first and second clamping rollers 4, 5.

[0065] Furthermore, such a single piece allows for a cost-effective design of the filament feeder 1, for example, by stamping the first biasing portion 20 and the first and second support portions 10, 11 from a single piece of sheet material (e.g., sheet metal), and by stamping the second biasing portion 21 and the third and fourth support portions 12, 13 from a single piece of sheet material (e.g., sheet metal).

[0066] According to the present invention, the suspension system S is arranged to allow lateral movement of the first and second clamping rollers 4, 5 relative to the channel 3 so as to provide a variable distance D+ΔD between the first roller axis 4a and the second roller axis 5a. However, the variable distance D+ΔD may need to be kept above a lower limit to prevent excessive clamping of the filament F, and kept below an upper limit to prevent disengagement of the first drive gear 6 and the second drive gear 7.

[0067] For example, in Figure 3In FIG, it is shown that the first support portion 10 can include a first transverse inward protrusion 22, and wherein the second support portion 11 includes a second transverse inward protrusion 23, and wherein the suspension system S is configured to allow the first and second transverse inward protrusions 22, 23 to abut when the variable distance D+ΔD reaches a lower limit. By means of such inward protrusions 22, 23, it is thus possible to prevent the variable distance D+ΔD from becoming too small. Similarly, in Figure 4 , it is shown that the third support portion 12 may include a third lateral inward protrusion 24, and wherein the fourth support portion 13 may include a fourth lateral inward protrusion 25, and wherein the suspension system S is configured to allow the third and fourth lateral inward protrusions 24, 25 to abut when the variable distance D+ΔD reaches a lower limit. The inward protrusions 22, 23 also prevent the variable distance D+ΔD from becoming too small.

[0068] Conversely, in order to maintain the variable distance D+ΔD below the upper limit, an embodiment may be provided in which the first support portion 10 comprises a first lateral outward protrusion 26 and in which the second support portion 11 comprises a second lateral outward protrusion 27, and in which the suspension system S is configured to allow the first and second lateral outward protrusions 26, 27 to abut against the first support plate 8 when the variable distance D+ΔD reaches the upper limit.

[0069] Likewise, the third support portion 12 may include a third lateral outward protrusion 28, and wherein the fourth support portion 13 may include a fourth lateral outward protrusion 29, and wherein the suspension system S is configured to allow the third and fourth lateral outward protrusions 28, 29 to abut the second support plate 9 when the variable distance D+ΔD reaches an upper limit.

[0070] It is worth noting that in one embodiment, the first, second, third and fourth transverse outward protrusions 26, 27, 28, 29 may be arranged in the plane of the first and second support plates 8, 9 to allow for the following: Figure 3 and Figure 4 That is, in this embodiment, the outward projections 26, 27, 28, 29 are flush with the respective first and second support plates 8, 9, thereby minimizing the thickness T of the filament feeder 1.

[0071] Figure 6 A perspective view of yet another embodiment is shown. In this embodiment, the feeder 1 comprises a feeder body 2 comprising a sawtooth-shaped middle portion having a smaller thickness than the outer ends of the feeder body 2 when viewed from above. As a result, a cross section in a plane perpendicular to the feeder channel 3 has a shape similar to the Roman numeral 1 (i.e., I). This embodiment also shows a similar Figure 3 The similarity of the implementation method. Figure 6In the embodiment, the suspension system S further comprises first and second support parts 10, 11 comprising holes to receive roller shafts 14, 15. In addition, the suspension system S comprises first and second laterally outward projections 26, 27. However, in Figure 6 In the embodiment of the present invention, the laterally outward projections 26, 27 will abut against the outer walls or edges 61, 62 of the feeder body 2. Another difference is that in Figure 6 In FIG, the suspension system S comprises two support arms 63, 64 respectively connected to the first and second support parts 10, 11. The support arms 63, 64 are pivotably connected to the feeder body 2 such that the support arms 63, 64 can pivot about pivot points 65, 66.

[0072] Figure 7A and Figure 7B 1 and 2. The adjustable filament feeder 1 is shown in relative side views according to an embodiment of the present invention. In the illustrated embodiment, the first support plate 8 includes an adjustable first lever portion 30 having a first lever end 30a and a second lever end 30b. The first lever end 30a is pivotally connected to the feeder block 2 at a first lever pivot point p5. The second support plate 9 includes an adjustable second lever portion 31 having a third lever end 31a and a fourth lever end 31b, wherein the third lever end 31a is pivotally connected to the feeder block 2 at a second lever pivot point p6.

[0073] As further shown, the first lever portion 30 is connected to the first and second support portions 10, 11 between a first lever end 30a and a second lever end 30b to position the first and second support portions 10, 11 laterally relative to the channel 3. The second lever portion 31 is connected to the third and fourth support portions 12, 13 between a third lever end 31a and a fourth lever end 31b to position the third and fourth support portions 12, 13 laterally relative to the channel 3. In this embodiment, the first and second lever portions 30, 31 can be adjusted by simultaneously moving the second and fourth lever ends 30b, 31b up and down as indicated by the movement direction U. This pivots the first and second lever portions 30, 31 and, thereby, moves the first, second, third, and fourth support portions 10, 11, 12, 13, and in particular, the first and second clamping rollers 4, 5, laterally relative to the channel 3. As depicted, in one embodiment, the first, second, third, and fourth support portions 10, 11, 12, 13 can be viewed as swing arms that are pivotally arranged at respective first, second, third, and fourth pivot points p1, p3, p4, and p5. The aforementioned first and second lateral displacements Δd1 , Δd2 of the first and second clamping rollers 4 , 5 are allowed by pivoting these oscillating arms 10 , 11 , 12 , 13 .

[0074] In an advantageous embodiment, the second and fourth lever ends 30b, 31b can be resiliently connected to the feeder block 2 to obtain a biased engagement of the first and second clamping rollers 4, 5 towards the channel 3, i.e., the filament F. Likewise, in a further embodiment, the second and fourth lever ends 30b, 31b can be adjustably connected to the feeder block 2, allowing the aforementioned first and second channel distances d1, d2 relative to the central axis C to be set, and wherein the adjustable connection exhibits elasticity to provide variable first and second lateral displacements Δd1, Δd2. In an exemplary embodiment, the second and fourth lever ends 30b, 31b can be connected to the feeder block 2 by one or more spring elements (not shown).

[0075] exist Figure 7A and Figure 7B In an embodiment of the present invention, the first support plate 8 may include a first and a second pivot portion 16, 17, and the second support plate 9 includes a third and a fourth pivot portion 18, 19, wherein the first and second pivot portions 16, 17 are pivotally connected to the first and second support portions 10, 11, respectively, and to the first lever portion 30. The third and fourth pivot portions 18, 19 are pivotally connected to the third and fourth support portions 12, 13, respectively, and to the second lever portion 31. In this embodiment, the first, second, third and fourth pivot portions 16, 17, 18, 21 provide a symmetrical arrangement of the first, second, third and fourth support portions 10, 11, 12, 13 relative to the channel 3 by applying a positive connection between the first and second lever portions 30, 31 and the first, second, third and fourth support portions 10, 11, 12, 13.

[0076] In an advantageous embodiment, the first lever portion 30 , the first and second pivot portions 16 , 17 and the first and second support portions 10 , 11 form a single piece; and

[0077] In this embodiment, the second lever portion (31), the third and fourth pivot portions 18, 19 and the third and fourth support portions 12, 13 are also formed as a single piece. This embodiment promotes cost-effective manufacturing and provides a thin suspension system S. For example, the first support plate 8 and the second support plate 9 can both be made of a sheet-based material (e.g., sheet metal) that is stamped so that the first support portion 10, the second support portion 11, the third support portion 12 and the fourth support portion 13, the first pivot portion 16, the second pivot portion 17, the third pivot portion 18 and the fourth pivot portion 19 and the first lever portion 30 and the second lever portion 31 are formed integrally. Here, each of the first, second, third and fourth pivot portions 16, 17, 18, 19 can be regarded as a sufficiently thin swing arm to allow elastic behavior at the first, second, third and fourth pivot points p7, p8, p9, p10. In order to increase the elasticity, each of the first, second, third and fourth pivoting parts 16, 17, 18, 19 may comprise two opposite narrow ends for obtaining the associated pivoting points p7, p7, p9, p10 as shown.

[0078] Now refer to Figure 8 , in which a perspective view of two clamping rollers 4, 5 according to an embodiment of the present invention is shown. In this embodiment, the first drive gear 6 and the first clamping roller 4 are formed as a single piece, and wherein the second drive gear 7 and the second clamping roller 5 are formed as a single piece. That is, the first and second clamping rollers 4, 5 are formed integrally with the first and second drive gears 6, 7, respectively, and are journaled to rotate about the first and second roller shafts 14, 15. Although not shown here, the first and second roller shafts 14, 15 are suspended by the first and second support parts 11, 12, as shown Figure 1 7 . In this embodiment, the first and second drive gears 6 , 7 are provided at first ends of the first and second roller shafts 14 , 15 , and the first and second clamping rollers 4 , 5 are provided at opposite second ends of the first and second roller shafts 14 , 15 .

[0079] Figure 9A top view of two clamping rollers 4 and 5 according to another embodiment of the present invention is shown. In this embodiment, the first drive gear 6 and the first clamping roller 4 are formed into a single piece, and the second drive gear 7 and the second clamping roller 5 are formed into a single piece. The first clamping roller 4 is provided with a circumferentially arranged annular first groove g1, and the second clamping roller 5 is provided with a circumferentially arranged annular second groove g2. The first and second grooves g1 and g2 are configured to clamp the filament F. This embodiment is provided with annular grooves g1 and g2 for evenly distributing the clamping on the round filament F. Other cross-sections of the grooves g1 and g2 are possible, such as parabolic or conical shapes. In addition, a gear meshing between the first drive gear 6 and the second drive gear 7 is provided on both sides of the grooves g1 and g2, so that the tooth force applied to the first drive gear 6 is arranged symmetrically with respect to the first groove g1, and the tooth force applied to the second drive gear 7 is arranged symmetrically with respect to the second groove g2. As a result, the first and second rollers 14 and 15 are evenly loaded along their lengths.

[0080] It is noteworthy that in this embodiment, the first clamping roller 4 and the first drive gear 6 are integrally formed and can be regarded as a single elongated first drive gear 6 provided with a circumferential annular first groove g1. Similarly, the second clamping roller 5 and the second drive gear 7 are integrally formed and can be regarded as a single elongated second drive gear 7 provided with a circumferential annular second groove g2.

[0081] Figure 10 A top view of two clamping rollers 4, 5 according to a third embodiment of the present invention is shown. In this embodiment, the first drive gear 6 and the first clamping roller 4 form a single piece provided with a circumferentially arranged V-shaped first groove g1. The second drive gear 7 and the second clamping roller 5 form a single piece provided with a circumferentially arranged V-shaped second groove g2. The first and second grooves g1, g2 are configured to clamp and engage with the filament F. This embodiment also provides a gear engagement between the first and drive gears 6, 7 on both sides of the V-shaped grooves g1, g2. In particular, the tooth forces applied to the first drive gear 6 are arranged symmetrically with respect to the first groove g1, and the tooth forces applied to the second drive gear 7 are arranged symmetrically with respect to the second groove g2.

[0082] Figure 11 1 shows a top view of two clamping rollers 4, 5 according to a fourth embodiment of the present invention. In this embodiment, Figure 10 Each of the first and second V-shaped grooves g1 , g2 of the embodiment further comprises a flat bottom provided with a protruding surface texture ST configured to increase gripping of the filament F.

[0083] for Figures 9 to 11In an embodiment, by selecting annular or V-shaped grooves g1, g2, with or without surface texture, the gripping of the filament F can be adjusted to achieve specific feeding performances.

[0084] Figure 12 A main drive gear 32 is shown according to an embodiment of the present invention. In the embodiment shown, the filament feeder 1 can include a driven worm gear 32 that meshes with the first drive gear 6 or the second drive gear 7. The worm gear 32 allows for a compact design and can be arranged at various angles (α) while maintaining meshing with the first drive gear 6 or the second drive gear 7.

[0085] The filament feeder 1 of the present invention may be used in a print head, wherein the filament feeder 1 feeds the filament F to a nozzle of the print head, which nozzle is arranged to deposit the molten filament F onto a build table.

[0086] The filament feeder of the present invention may also be used in an FFF printing device to transport the filament F to a printing head via a Bowden tube.

[0087] Figure 13 There is schematically shown an FFF printer 33 comprising a filament feeder 1. As depicted, the filament feeder 1 allows the filament F to be conveyed to the nozzle 35 of the print head 34 by means of a first 4 and a second 5 nip roller.

[0088] from Figure 13 It is also clear that the print head 34 may include a filament feeder 1 for delivering the filament F, wherein the print head 34 may be configured to deposit the filament F onto a build table 36 of the FFF printer 33 .

[0089] The invention has been described above with reference to a number of exemplary embodiments shown in the accompanying drawings. Modifications and alternative implementations of some parts or elements are possible and are included within the scope of protection as defined in the appended claims.

Claims

1. A filament feeder (1) for a fused filament fabrication printer, the filament feeder comprising: a feeder body (2) comprising a passage (3) for guiding the filament (F) therethrough; a first clamping roller (4) and a second clamping roller (5) arranged on opposite sides of the channel (3) for clamping engagement with the filament (F), wherein the first clamping roller (4) is rotatably arranged about a first roller axis (4a) and the second clamping roller (5) is rotatably arranged about a second roller axis (5a); a first driving gear (6) for driving the first clamping roller (4), the first driving gear (6) being rotatably arranged around the first roller axis (4a); a second drive gear (7) for driving the second clamping roller (5), the second drive gear being rotatably arranged around the second roller axis (5a), a suspension system (S) for suspending the first clamping roller (4) and the second clamping roller (5) and the first drive gear (6) and the second drive gear (7), wherein the suspension system (S) is arranged to allow the first clamping roller (4) and the second clamping roller (5) to move laterally relative to the channel (3) to provide a variable distance (D+ΔD) between the first roller axis (4a) and the second roller axis (5a).

2. The filament feeder according to claim 1, in, The first roller axis (4a) is arranged at a first channel distance (d1) relative to a central axis (C) of the channel (3), and wherein the second roller axis (5a) is arranged at a second channel distance (d2) relative to the central axis (C) of the channel, and The first channel distance (d1) and the second channel distance (d2) are respectively variable over a substantially equal first lateral displacement (Δd1) and a second lateral displacement (Δd2).

3. The filament feeder according to claim 1 or 2, wherein: The suspension system (S) comprises an elastic suspension member arranged to elastically bias the first clamping roller (4) and the second clamping roller (5) towards the filament (F).

4. The filament feeder according to any one of claims 1 to 3, wherein: The suspension system comprises a first support plate (8) and a second support plate (9) mounted on opposite sides of the feeder body (2), wherein the first support plate (8) comprises a first support portion (10) and a second support portion (11), and wherein the second support plate (9) comprises a third support portion (12) and a fourth support portion (13); wherein the first clamping roller (4) and the second clamping roller (5) each include a first roller shaft (14) and a second roller shaft (15), respectively, and wherein the first roller shaft (14) is suspended by the first support portion (10) and the third support portion (12), and wherein the second roller shaft (15) is suspended by the second support portion (11) and the fourth support portion (13), and The first supporting portion (10), the second supporting portion (11), the third supporting portion (12) and the fourth supporting portion (13) are capable of moving laterally relative to the channel (3).

5. The filament feeder according to claim 4, wherein The first support portion (10), the second support portion (11), the third support portion (12) and the fourth support portion (13) are pivotally arranged in respective planes of the first support plate and the second support plate.

6. The filament feeder according to claim 4 or 5, wherein: The first support plate (8) comprises a first pivot portion (16) and a second pivot portion (17), and wherein the second support plate (9) comprises a third pivot portion (18) and a fourth pivot portion (19), wherein the first pivot portion (16) and the second pivot portion (17) pivotally connect the first support plate (8) to the first support portion (10) and the second support portion (11), and Wherein, the third pivot portion (18) and the fourth pivot portion (19) pivotally connect the second support plate (9) to the third support portion (12) and the fourth support portion (13).

7. The filament feeder according to claim 6, wherein: The first support plate (8), the first support portion (10) and the second support portion (11) and the first pivot portion (16) and the second pivot portion (17) form a single piece, and wherein The second support plate (9), the third support portion (12) and the fourth support portion (13) as well as the third pivot portion (18) and the fourth pivot portion (19) form a single piece.

8. The filament feeder according to claim 6 or 7, wherein: The first support plate (8) comprises a transversely elastic first biasing portion (20) connecting the first support portion (10) and the second support portion (11), and wherein the second support plate (9) comprises a transversely elastic second biasing portion (21) connecting the third support portion (12) and the fourth support portion (13).

9. The filament feeder according to claim 8, wherein The first biasing portion (20) and the first support portion (10) and the second support portion (11) form a single piece, and wherein the second biasing portion (21) and the third support portion (12) and the fourth support portion (13) form a single piece.

10. The filament feeder according to any one of claims 6 to 9, wherein: The first support portion (10) includes a first lateral inward protrusion (22), and wherein the second support portion (11) includes a second lateral inward protrusion (23), wherein the suspension system (S) is configured to allow the first lateral inward protrusion (22) and the second lateral inward protrusion (23) to abut when the variable distance (D + ΔD) reaches a lower limit.

11. The filament feeder according to any one of claims 6 to 10, wherein: The first support portion (10) includes a first lateral outward protrusion (26), and wherein the second support portion (11) includes a second lateral outward protrusion (27), and wherein the suspension system (S) is configured to allow the first lateral outward protrusion (26) and the second lateral outward protrusion (27) to abut against an edge of the first support plate (8) or an edge of the feeder body (2) when the variable distance (D + ΔD) reaches an upper limit.

12. The filament feeder according to claim 4 or 5, wherein: The first support plate (8) includes an adjustable first lever portion (30) having a first lever end (30a) and a second lever end (30b), the first lever end (30a) being pivotally connected to the feeder body (2) at a first lever pivot point (P5), and wherein The second support plate (9) comprises an adjustable second lever portion (31) having a third lever end (31a) and a fourth lever end (31b), the third lever end (31a) being pivotally connected to the feeder body (2) at a second lever pivot point (P6), wherein the first lever portion (30) is connected to the first support portion (10) and the second support portion (11) between the first lever end (30a) and the second lever end (30b) for laterally positioning the first support portion (10) and the second support portion (11) relative to the channel (3), and The second lever portion (31) is connected to the third support portion (12) and the fourth support portion (13) between the third lever end (31a) and the fourth lever end (31b) for laterally positioning the third support portion (12) and the fourth support portion (13) relative to the channel (3).

13. The filament feeder according to claim 12, wherein: The first support plate (8) comprises a first pivot portion (16) and a second pivot portion (17), and wherein the second support plate (9) comprises a third pivot portion (18) and a fourth pivot portion (19), wherein the first pivoting portion (16) and the second pivoting portion (17) are pivotally connected to the first supporting portion (10) and the second supporting portion (11) and the first lever portion (30), respectively, and Wherein, the third pivot portion (18) and the fourth pivot portion (19) are pivotally connected to the third support portion (12) and the fourth support portion (13) and the second lever portion (31), respectively.

14. The filament feeder according to claim 13, wherein The first lever portion (30), the first pivot portion (16) and the second pivot portion (17) and the first support portion (10) and the second support portion (11) form a single piece, and wherein the second lever portion (31), the third pivot portion (18) and the fourth pivot portion (19) and the third support portion (12) and the fourth support portion (13) form a single piece.

15. The filament feeder according to any one of claims 12 to 14, wherein: The second lever end (30b) and the fourth lever end (31b) are elastically connected to the feeder body (2).

16. An FFF printer comprising the filament feeder according to any one of claims 1-15.

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