Title of Invention

EJECTOR DEVICE FOR AN INJECTION MOULDING MACHINE FOR PLASTICS

Abstract Ejector device for an injection-moulding machine for plastics The invention relates to an ejector device for an injection-moulding machine for plastics with at least one ejector bolt, which can be moved by an actuator towards the mould and away from it through the center of a movable platen. In this arrangement, a linear motor (21) is provided as the actuator, arranged outside the central axis (I) on the movable platen (12), and bar-shaped power transmission elements (30) are provided, by which the linear motor can be brought into operative connection with the ejector bolt (41). Related figure: Figure 1
Full Text Ejector device for an injection-molding machine for plastics
Description
The invention relates to an ejector device for an injection-moulding machine for plastics with at least one ejector bolt, which can be moved by an actuator towards the mould and away from it through the center of a movable platen.
EP 0 585 671 Al discloses an ejector for moulds in injection-moulding machines in which there is mounted an electric motor which is provided on a platen and is in constant adjusting connection via a gear mechanism with a rotationally .drivable threaded spindle, which is connected to an ejector pin.
EP 0 890 426 A2 discloses a device in which a servo motor is connected via an endless belt to a be11screw, which is in operative connection with an ejector bolt.
The ejector units known from the aforementioned documents suffer not only from the disadvantage of a complicated construction but also from appreciable wear.
The object of the invention is to provide an ejector device for an injection-moulding machine which, while being of a simple construction and economical in its energy consumption, requires little maintenance, is reliable and takes up only a small free space in the region of the drive of the movable platen.
The invention achieves this object by the features of Claim 1. The remaining claims comprise advantageous developments of the invention.
According to the invention, a linear motor which is connected via bar-shaped power transmission elements to the ejector bolt is provided outside the central axis of the injection-moulding machine. The linear motor is fastened on the movable platen and is

arranged parallel or at right angles to the principal axis of the latter.
In one embodiment of the invention, a two-armed lever is used, fastened at one end in an angularly movable manner on a bracket of the movable platen and connected at the other end via a tension butt strap to the linear motor- Provided approximately centrally is a compression butt strap, which is in operative connection with the ejector bolt.
In another embodiment of the invention, a two-armed lever is provided, one end of which is connected to the ejector bolt, the other end of which is in connection with the linear motor via a compression butt strap and which is in connection with the movable platen approximately centrally via a tension butt
strap-
The two-armed lever is designed in such a way that the lever ratios can be set and, in one embodiment, the lever has various retaining elements, while in a further embodiment the lever is telescopically designed, in order to be able to set the lever ratios of the lever part a, which is inclined towards the linear motor, and the lever part b, which is inclined towards the ejector bolt.
In a further embodiment of the invention, a gear mechanism formed by a two-armed lever and a one-armed lever is provided, permitting a linear guidance of the ejector bolt over an adequate range. This embodiment makes it possible to dispense with the use of a bearing of the ejector bolt. Where bearings are used, sliding bearings, in particular sintered bearings, are provided.
Used as the linear motors are electric motors which have ball screws or planetary screws. It is also proposed to use as the linear motors reluctance motors in which the inductor comb is in connection either with the movable platen or via a compression or tension butt strap with the two-armed lever.

In a further embodiment of the invention, a rigid lever is used, driven by a linear motor arranged parallel to the principal axis.
An example of the invention is represented in the attached drawing, in which:
Figure 1 shows an ejector device with a two-armed lever, which centrally drives the ejector bolt.
Figure 2 shows an actor device with a two-armed lever in which the ejector bolt is arranged at the end.
Figure 3 shows an ejector device in which the levers form a gear mechanism.
Figure 4 shows an ejector device in which the linear motor is arranged perpendicularly in relation to the principal axis.
Figure 5 shows an ejector device with a rigid lever.
All the figures show a fixed platen 11 and a movable platen 12 of an injection-moulding machine 10. Fastened in each case on the movable platen 12 is a linear motor 21, which is in operative connection via lever-shaped power transmission elements 30 with an ejector bolt 41, which can be guided centrally through the movable platen 12.
In Figure 1, the ejector bolt 41 is fastened on an ejector plate 44, which has bearings 42 and 43 which correspond with guide bolts 16, 17 attached to the movable platen 12.
The ejector plate 44 is connected via a compression butt strap 33 to a two-armed lever 31. The two-armed lever 31 is fastened at one end in an angularly movable manner to a bracket 13 and connected at its other end via a tension butt strap 32 to the linear motor 21- The linear motor 21 is designed as a reluctance motor 23, the inductor comb 24 of which is arranged on the head of the platen 12 parallel to the principal axis I.
The ratios of the lever part a with respect to the lever part b of the two-armed lever 31 can be set

via retaining elements 34 and 35, respectively, in interaction with the bracket 13 and 14, respectively. In Figure 2, two ejector bolts 41 are provided on the ejector plate 44. The ejector plate 44 is in this case fastened on the retaining bar 45, which is guided through a bearing 15 which is fastened on the movable platen 12.
The end of the retaining bar 45 is fastened in an angularly movable manner to one end of the two-armed lever 31.
The two-armed lever is held approximately centrally by means of a tension butt strap 32 on brackets 13 or 14, which are fastened on the movable platen 12.
Provided at the other end of the two-armed lever 31 is a compression butt strap 33, which is in operative connection with a spindle 22 of the linear motor 21 provided here.
In Figure 3, the retaining bar 45, which is connected to the ejector plate 44 on which the ejector bolt 41 is located, is connected both to a one-armed lever 37 and to a two-armed lever 31. The one-armed lever 37 is in this case connected at the other end to a bracket 14, and the two-armed lever 31 is connected approximately centrally via a bracket 13 to the movable platen. The points of articulation and the lever ratios are matched with one another in such a way that the ejector bolt 41 is guided on the central axis I for an adequately great distance.
The two-armed lever 31 is designed as a telescope, so that the ratios of the lever arms a and b can be set in a steeples manner as desired.
One end of the two-armed lever 31 is connected via a compression butt strap 33 to the linear motor 21, which is designed as a reluctance motor 23. The inductor comb 24 has adjusting elements 25, which allow an adjustability of the movement axis II in relation to the central axis I.

In Figure 4, the movement axis III is provided perpendicularly in relation to the central axis I. The linear motor 21 used is in this case held in an angularly movable manner on a bracket 13, 14.
The two-armed lever 31 has an angular shape and is connected in an angularly movable manner to the movable platen 12 approximately centrally on a bracket 13.
Provided at the other end of the two-armed lever 31 is a compression butt strap 33, which is connected to the retaining bar 45, which is connected to the ejector plate 44 and the ejector bolt 41 fastened on the latter.
The retaining bar 45 is mounted in a bearing 15, which is in connection with the movable platen 12.
Figure 5 has an ejector bolt 41, which is connected to an ejector plate 44 and is in operative connection with the linear motor 21 via a rigid arm 39. One end of the rigid arm 39 forms the inductor comb 24 of the reluctance motor 23.
The ejector plate 44, connected to the rigid arm 39, is mounted by the bearings 42 and 43 on guide bolts 16 and 17, which are fastened on a movable platen 12.

List of items
Injection-moulding machine
11 Fixed platen
12 Movable platen
13 First bracket
14 Second bracket
15 Bearings 16, 17 Guide bolts
Actuator
21 Linear motor
22 Spindle
23 Reluctance motor
24 Inductor comb
25 Adjusting element
Power transmission elements
31 Two-armed lever
32 Tension butt strap
33 First compression butt strap 34, 35 Retaining element

36 Telescope
37 One-armed lever
38 Second compression butt strap
39 Rigid arm
Ejection
41 Ejector bolt 42, 43 Ejector bearings 44 Ejector plate
I Central axis
II Movement axis of the linear motor
III Direction of movement of the linear motor perpendicularly in relation to the central axis
a Lever part inclined to the linear motor b Lever part inclined to the ejector bolt




1. Ejector device for an injection-moulding machine for plastics with at least one ejector bolt, which can be moved by an actuator towards the mould and away from it through the centre of a movable platen, characterized in that a linear motor (21) is provided as the actuator, arranged outside the central axis (I) on the movable platen (12), and in that bar-shaped power transmission elements (30) are provided, by which the- linear motor can be brought into operative connection with the ejector bolt (41).
2. Ejector device according to Claim 1, characterized in that the power transmission elements (30) have at least one two-armed lever (31) , which is connected at one end via a tension butt strap (32) to the linear motor (21) and is fastened at the other end in an angularly movable manner on a braclcet (13) provided on the movable platen (12) , and in that the lever (31) is connected approximately centrally via a compression butt strap (33) to the ejector bolt (41).
3. Ejector device according to Claim 1, characterized in that the power transmission elements (30) have at least one two-armed lever (31) , which is connected at one end via a tension butt strap (32) to the linear motor (21) and is connected at the other end to the ejector bolt (41), and in that the lever (31) is connected approximately centrally via a compression butt strap (33) to the movable platen (12).
4. Ejector device according to either of Claims 2 and 3, characterized in that the two-armed lever (31) has at least two retaining elements (34, 35), by which the length (a) of the lever part inclined towards the drive and the length (b) of the remaining lever part are variable.
5. Ejector device according to Claim 4, characterized in that the power transmission elements (30) have a two-armed lever (31) which, together with a one-armed lever (37) arranged approximately parallel to

the lever (31), forms a gear mechanism with which the ejector bolt (41) can be moved over a predeterminable range linearly and thereby parallel to the movement axis (II) of the linear motor (21), the two-armed lever (31) being connected at one end via a compression butt strap (33) to the ejector bolt (41) and via a second compression butt strap (38) to the linear motor (21), and in that brackets (13, 14) on which the levers (31, 37) are fastened in an angularly movable manner are provided on the movable platen (12),
6. - Ejector device according to Claim 1,
characterized in that the power transmission element
(30) is a rigid arm (39) , by which the ejector bolt
(41) can be moved parallel to the movement axis (II) of
the linear motor (21).
7. Ejector device according to one of the
aforementioned claims, characterized in that a bearing
(15) which allows unhindered linear movement of the ejector bolt (41) is provided on the movable platen
(12) .
8. Ejector device according to one of the aforementioned claims, characterized in that guide bolts (16, 17) are provided on the movable platen (12) and, by means of bearings (42, 43), are in connection with an ejector plate (44) on which at least one ejector bolt (41) is fastened.
9. Ejector device according to Claim 7 or .8, characterized in that the bearing (15, 42, 43) is designed as a sliding bearing, for example as a sintered bearing.
10. Ejector device according to Claim 1, characterized in that the linear motor (21) has a ballscrew or planetary screw (22) driven by an electric motor.
11. Ejector device according to Claim 1, characterized in that the linear motor (21) is a reluctance motor (23) , the inductor comb (24) of which is connected to the two-armed lever (31) via a compression butt strap (33).

12. Ejector device according to Claim 1, characterized in that the linear motor (21) is a reluctance motor (23), which is in operative connection with an inductor comb (24) fastened on the movable platen (12) .
13. Ejector device according to Claim 12, characterized in that the inductor comb (24) has adjusting elements (25), by means of which it is fastened adjustably in height on the movable platen (12) .
14 .- Ejector device according to Claim 2, characterized in that the two-armed lever (31) is designed as a telescope (36), by which the length ratios of the lever parts (a, b) are steplessly variable.
15. Ejector device for an injection-raouldiiig machine for plastics substantially as herein described with reference to the accompanying drawings.


Documents:

854-mas-2000-abstract.pdf

854-mas-2000-assignement.pdf

854-mas-2000-claims filed.pdf

854-mas-2000-claims grand.pdf

854-mas-2000-correspondnece-others.pdf

854-mas-2000-correspondnece-po.pdf

854-mas-2000-description(complete) filed.pdf

854-mas-2000-description(complete) grand.pdf

854-mas-2000-drawings.pdf

854-mas-2000-form 1.pdf

854-mas-2000-form 19.pdf

854-mas-2000-form 26.pdf

854-mas-2000-form 3.pdf

854-mas-2000-form 5.pdf

854-mas-2000-form 6.pdf

854-mas-2000-other documents.pdf

abs-854-mas-2000.jpg


Patent Number 201515
Indian Patent Application Number 854/MAS/2000
PG Journal Number 08/2007
Publication Date 23-Feb-2007
Grant Date 07-Aug-2006
Date of Filing 10-Oct-2000
Name of Patentee DEMAG ERGOTECH GMBH
Applicant Address ALTODORFER STR.15, 90571 SCHWAIG
Inventors:
# Inventor's Name Inventor's Address
1 DIPL.ING HOLGER SCHMIDT NEAM WALLGRABEN 30 D-06567 BAD FRANKENHAUSEN
PCT International Classification Number B29C45/40
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 100 05 676.8 2000-02-07 Germany