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Title:
A HEAD-SWITCHING MECHANISM IN A TWO-HEAD THREE-DIMENSIONAL PRINTER
Document Type and Number:
WIPO Patent Application WO/2017/058035
Kind Code:
A1
Abstract:
The head-switching mechanism in a two-head three-dimensional printer contains an immobile body made of screwed plates, whereby a rotating shaft (2) is mounted in the bottom plate (20) and the top plate (14). The shaft (2) has guides (5) on which sliding rolling carriages (7) of the mounts (8) of the heads (9) are mounted. The mounts (8) are connected to the top plate (14) with ties (6) that have swinging bushings.

Inventors:
GĄSIOREK DAMIAN (PL)
MACHOCZEK TOMASZ (PL)
WILK KRZYSZTOF (PL)
WOLNICKI PRZEMYSŁAW (PL)
ZACHWIEJA MARCIN (PL)
Application Number:
PCT/PL2016/000109
Publication Date:
April 06, 2017
Filing Date:
September 27, 2016
Export Citation:
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Assignee:
3D GENCE SPÓŁKA Z OGRANICZONĄ ODPOWIEDZIALNOŚCIĄ (PL)
International Classes:
B29C64/227; B29C48/30; B29C64/209; B29C67/02
Foreign References:
CN203157146U2013-08-28
CN103465633A2013-12-25
CN104626589A2015-05-20
CN204109371U2015-01-21
Other References:
See also references of EP 3356117A4
Attorney, Agent or Firm:
JAROSZ, Wojciech (PL)
Download PDF:
Claims:
Claims

1. A head-switching mechanism in a two-head three-dimensional printer having a body fitted with a servomotor, a drive transmission assembly, and two head mounts fitted with heads, characterized in that the body of the mechanism consists of a base (21), a bottom plate (20), a basic vertical plate

(19) , and a top plate (14) connected with screws, whereby in the top plate (14) and the lower plate

(20) , a vertical shaft (2) is fixed with the freedom to rotate, with a toothed quarter-wheel (1) meshed with a drive geared wheel (11) of the servomotor (12) located on the top plate (14), whereby the shaft (2) has vertical guides (5) for two rolling carriages (7) on which mounts (8) fitted with print heads (9) are fixed, and the mounts are connected at the top to the top plate (14) using the ties (6) with swinging bushings at their ends, whereby between the location where the ties (6) are fastened to the top plate (14) and the shaft (2) on the top plate (14), a calibrating tensometric sensor (3) is fastened, while the shaft (2) has two steel retaining spacers (16) located at 90° intervals, with a cylindrical articulation in the middle between them, on which a spring holder is fastened with one end, while its other end is fastened, with the freedom to rotate, to the body, while two cuboidal spigots (17) are screwed to the vertical plate (19) and fit into the holes in the base plate (18) and blocked in it with a screw knob (13), while between the body and the base plate (18) there is a multi-pin cable socket.

2. A mechanism according to claim 1, characterized in that the body is fitted in the lower part with a bin (22) that has rectangular holes under the idle position of the heads (9) and has oblique wails near the holes that constitute platforms under the nozzles of the heads (9) right in front of the idle position.

3. A mechanism according to claim 1, characterized in that it has, in its lower part, a fan located in the base (21).

4. A mechanism according to claim 1, characterized in that the plates of the body and the head mounts are made of aluminum.

Description:
A head-switching mechanism in a two-head three-dimensional printer

Field of the invention

The invention pertains to a head-switching mechanism in a two-head three-dimensional printer. State of the art

In a three-dimensional printer, thermoplastic heated up to a semi-iiquid state is fed to heads sliding in three dimensions and applied in spots or in layers. In a two-head printer, one head receives plastic ized main thermoplastic material and the other head receives another thermoplastic material of different mechanical or optical properties. A two-head three-dimensional printer must have a head-switching mechanism for selection of the working condition of one of the heads.

In a known head-switching mechanism of a two-head printer, the head that is idle at a given time is located outside of the work table of the printer. The mechanism is fitted with one head associated with an extruder that feeds the material. If the head needs to be changed, the mechanism puts one head outside of the work table and takes the other head.

In another known solution, the mechanism is equipped with two heads that are fixed in the mechanism with possibility to slide vertically. The working head is located below the idle head. For vertical movement of the heads, the mechanism is fitted with cams and/or eccentrics driven with servomechanisms or electromagnets. In order to change the head, the working head is lifted and the other, idle, head is lowered to the working position.

The Polish patent application no. P.412 045 describes a head switching mechanism in which heads are switched as a result of their rotation around a horizontal axis.

Summary of the invention

In the mechanism according to the invention, heads are switched as a result of a combination of rotation around the vertical axis of a shaft located in an immobile body and a translation movement along guides that are parallel to the axis of the shaft. The body, preferably made of aluminum, consists of plates located on the base and fixed with screws, whereby the vertical rotating shaft is set in the extreme top and bottom plate. The shaft has vertical guides with two sliding rolling carriages fixed located on them, which are fixed permanently to preferably aluminum mounts fitted with printing heads. The mounts are connected at the top with the top plate of the immobile body through ties that have swinging bushings on both ends. Between the location where the ties are fixed to the top plate and the shaft, there is a calibrating tensometric sensor.

The shaft is fitted with two steel retaining spacers placed at 90° intervals, with a cylindrical articulation in the center between them on which a spring holder is set with one end. The other end of the holder is fixed to the body with the freedom to rotate. Two cuboidal spigots are screwed to the vertical plate; the spigots are fit into the holes in the base plate and blocked in the plate with a crew knob. Between the body and the base plate, there is a multi-pin cable connector.

On the top end of the shaft, a toothed quarter-wheel is screwed, meshed with the drive geared wheel of the servomotor located on the top plate.

In one of the variants, the mechanism according to the invention has, preferably in the lower part of the body, a bin with rectangular holes below the idle position of the heads and oblique walls near the holes which constitute ramps under the nozzles of the heads just before the idle positions.

In another variant of the mechanism according to the invention, its base is equipped with a fan.

Concise description of the figures in the drawing

The object of the invention is shown in the embodiment in the drawing in which figure 1 shows the mechanism in an oblique view from the side of the head in the working position, fig. 2 shows the mechanism in an oblique view from the side of the head in the idle position, fig. 3 shows an enlarged part of the mechanism marked in fig. 2 which includes the guides and the ties, fig. 4 shows the mechanism in a front view, fig. 5 shows the mechanism in a top view, fig. 6 shows the mechanism in a bottom view, fig. 7 shows the mechanism in a side view from the side of the head in the idle position, fig. 8 shows the mechanism in a view from the other side, fig. 9 shows an enlarged part of the mechanism marked in fig. 8 which includes the fastening of the spring holder on the shaft, fig. 10 shows the mechanism in a back view on the side of the fastening to the manipulator of the printer with the locations of the cross-sections shown in the further figures in the drawing indicated, fig. 1 1 shows the mechanism in the A-A cross-section indicated in fig. 10, fig. 12 shows the mechanism in the B-B cross-section indicated in fig. 10, and fig. 13 shows the mechanism in the C-C cross-section indicated in fig. 10.

Implementation of the invention

The bottom plate 20 is screwed to the top part of the base 21, while bin 22, which constitutes a drainer for remains of thermoplastic material from the heads, whose oblique wall cleans the head before it is put in the idle position. The vertical plate 19 is fixed to the bottom plate 21, while the top plate 14 and two cuboidal spigots 17 are fixed to the vertical plate 19. The spigots 17 are fit into the holes of the base plate 18 and blocked in it with the screw knob 13. In the base plate there is a female part of the multi-pin cable connector, while the male part of the connector is located in the body. The base plate has the fastening part 10 which fixes it to the manipulator of the printer, fitted with holes for screws. If the mechanism is to be replaced with another mechanism, according to the invention, the base plate 18 stays fixed to the manipulator of the printer. The new mechanism is connected with the multi-pin connector and the screw knob 13 after the spigots 17 are slid in.

In the top plate 14 and bottom plate 20, the shaft 2 is fixed with possibility to rotate, with a toothed quarter- wheel 1 on its end, driven by the geared wheel 1 1 of the servomotor 12, screwed to the top plate 14. The rotating shaft 2 has two positions at 90° intervals, based on its two retaining spacers 16. In each of the extreme positions, it is blocked with the spring holder fixed with one end on the cylindrical articulation on the shaft 2 in the middle of the arch between the retaining spacers 16 and the other end, with the freedom to

rotate around the vertical axis in the body.

The shaft 2 has vertical guides 5 for the two rolling carriages 7, on which the aluminum mounts 8, fitted with the printing heads 9, are set. The mounts 8 of the heads 9 are connected in the top part with ties 6, which have swinging bushings on both ends, to the immobile top plate 14, When the shaft 2 and the guides 5 of the mounts 8 turn, the ties 6 constitute a vertical drive of the mounts 8 along the guides 5. Between the location where the ties 6 are fixed to the front part 4 of the top plate 14 and the shaft 2, the calibrating tensometric sensor 3 is fastened.

A beneficial effect of the invention is the significantly larger distance between the head in the idle state and the head in the working state compared to the solution where the heads are switched only around the horizontal axis, which is important in order to ensure lack of collision between the head in the idle state and the print area. Another beneficial effect is the reduction of the operating time needed to change the printing input material and the associated calibration and diagnostic works to be performed on the printer. The mechanism works beneficially during operation in elevated temperatures in heat chambers.