Claims:We Claim:

1. A moulding apparatus (100) comprising:
an ejection unit (200) having a primary ejection plate (110) and a secondary ejection plate (120) having a first and second opening (110a, 120a) respectively corresponding to each other;
wherein the ejection plates (110, 120) are engageably connected by a sliding member (130), the sliding member (130) is slidably arranged inside the first and the second openings (110a, 120a) of the primary ejection plate (110) and the secondary ejection plate (120), the sliding member (130) has at least one engaging portion (132) adapted to engage the primary ejection plate (110) with the secondary ejection plate (120),
wherein a guiding pin (140) having an inclined head (141) is arranged inside an inclined opening (130a) of the sliding plate (130),
wherein upon actuation of an actuator (500), the primary ejection plate (110) and the secondary ejection plate (120) moves together in a first direction (100a) and the sliding member (130) moves in the first direction (100a) and in a second direction (100b) such that the at least one engaging portion (132) disengages from the first opening (110a) of the primary ejection plate (110) thereby disengaging the primary ejection plate (110) from the secondary ejection plate (120).

2. The moulding apparatus (100) as claimed in claim 1, wherein the primary ejection plate (110) has a locking surface (112) inside the opening (110a) corresponding to the engaging portion (132) of the sliding member (130), the locking surface (112) of the primary ejection plate (110) sequentially engages or disengages with the engaging portion (132) according to the movement of the sliding member (130).

3. The moulding apparatus (100) as claimed in claim 1, wherein the guiding pin (140) is attached to a core block (410) of a die plate (400), with a proximal end of the guiding pin (140) connected to the die plate (400) of the moulding apparatus (100) and the distal end engageably connected to the sliding member (130).

4. The moulding apparatus (100) as claimed in claim 1, wherein the guiding pin (140) is arranged at the lower fixing plate (300).

5. The moulding apparatus (100) as claimed in claim 1, wherein the inclined opening (130a) of the sliding member (130) has an angular edge profile corresponding to the inclined head (141) of the guiding pin (140) such that the guiding pin (140) positively fits inside the sliding member (130).

6. The moulding apparatus (100) as claimed in claim 1, wherein when the sliding member (130) moves in the second direction towards the guiding pin (140), the engaging portion (132) of the sliding member (140) disengages from the opening (110a) of the primary ejection plate (110) such that the primary ejection plate (110) can move independently without the secondary ejection plate (120) to carry out a secondary ejection process.

7. The moulding apparatus (100) as claimed in claim 1, wherein a stopper assembly (150) is arranged to stop the further movement of the secondary ejection plate (120) along with the primary ejection plate (110) during a second stroke.

8. The moulding apparatus (100) as claimed in claim 7, wherein the stopper assembly (150) is an elongated member extending from the die plate (400), wherein when the sliding member (130) moves in the first direction, the secondary ejection plate (120) engages with the stopper assembly (150) and restricts the further movement of the secondary ejection plate (120), such that the primary ejection plate (110) can move independently without the secondary ejection plate (120) to carry out a secondary ejection process.

9. The moulding apparatus (100) as claimed in claim 1, wherein the secondary ejection plate (120) has sleeve pins configured thereon, and the primary ejection plate (110) has ejector pins assembled thereon, when the secondary ejection plate (120) having the sleeve pins stops, the primary ejection plate (110) having the ejector pins moves further to de-mould the part completely from the core block (410).
10. The moulding apparatus (100) as claimed in claim 1, wherein the second direction (100b) is substantially perpendicular to the first direction (100a).
, Description:Field of the Invention

[0001] The present invention relates to a moulding apparatus. More specifically, the present invention relates to a double ejection mechanism for an injection moulding apparatus.

Background of the Invention

[0002] Generally, an injection moulding apparatus consists of two segments, like a lower fixing plate and a movable die plate. The lower fixing plate has an injection nozzle attached to it, whereas a movable die plate has a cavity corresponding to an article with the lower fixing plate that is capable of moving relative to the fixing plate. An ejector assembly is provided between the fixing plate and the movable die plate that has an ejector pin and an ejector sleeve. In double ejection moulding apparatus, the ejector assembly includes a primary ejection plate and a secondary ejection plate. Both the ejection plates may be connected together. In double ejection moulding, the moulding is carried out in two stages, a primary process and a secondary process. The primary process includes the movement of both the ejection plate, whereas the primary ejection plate has to complete an additional stroke than the secondary ejection plate to complete the secondary process. During the secondary process, the primary ejection plate has to be disengaged with the secondary ejection plate so that the primary ejection plate can complete the double ejection moulding process.

[0003] The existing injection moulding tool makes use of spring-loaded latch mechanism to disengage the primary ejection plate and the secondary ejection plate, which tends to be less user friendly due to higher cost, complex design and working. It may tend to fail or function inefficiently due to continuous use that can lead to loss of time, labour, materials used and money.

[0004] Therefore, there is a need for an injection moulding apparatus, which may overcome a few or all the problems of the prior art.

Objects of the Invention

[0005] An object of the present invention is to provide an injection moulding apparatus, which has a simple design and durable during continuous production of mould.

[0006] Another object of the present invention is to provide an injection moulding apparatus, which is economical and robust in construction.

[0007] Yet another object of the present invention is to provide an injection moulding apparatus, which can be manufactured easily.

[0008] One more object of the present invention is to provide an injection moulding apparatus which can be easily operated.

Summary of the invention

[0009] According to the present invention, there is provided with a moulding apparatus in accordance with the present invention. The apparatus includes an ejection unit consisting of a primary ejection plate and a secondary ejection plate. Both the primary ejection plate and the secondary ejection plates may be arranged horizontally to a lower fixing plate and a die plate. The primary ejection plate may reside on an upper portion of the secondary ejection plate. Specifically, the primary ejection plate is adjacent to the die plate, and the secondary ejection plate is adjacent to the lower fixing plate.

[0010] In an embodiment, the primary ejection plate and the secondary ejection plate may be engageably connected by a sliding member. The sliding member is slidably arranged inside the primary ejection plate and the secondary ejection plate. Both the ejection plates are having a first and second opening respectively corresponding to each other. The sliding member has atleast one engaging portion which is adapted to engage the primary ejection plate with the secondary ejection plate. The primary ejection plate has a locking surface inside the opening corresponding to the engaging portion of the sliding member. The locking surface of the primary ejection plate may sequentially engage or disengages with the engaging portion according to the movement of the sliding member. The sliding member has an inclined opening corresponding to the openings of the ejection plates. Specifically, the openings of the ejection plates and the sliding plates are in-line with each other. The primary ejection plate has ejector pins assembled thereon, and the secondary ejection plate has sleeve pins configured on it.

[0011] Further, the moulding apparatus may be provided with a guiding plate. In an embodiment, the guiding pin may be arranged perpendicularly in between the die plate and the lower fixing plate. Specifically, a proximal end of the guiding pin is connected to the die plate, and a distal end is engageably connected to the sliding member. The guiding pin may be a cam-shaped arrangement with an inclined head arranged on a core block of the die plate. The proximal end of the guiding pin is connected to the core block. In another embodiment, the guiding pin is arranged at the lower fixing plate, and one end of the guiding pin engages with the sliding member to facilitate a linear movement.

[0012] During a primary stage of moulding, both the primary ejection plate and the secondary ejection plates are engaged together and move relative to each other towards the die plate. The moulding apparatus has a hydraulic actuator for actuating the “to” and “fro” movement of the primary and the secondary ejection plates between the lower fixing plate and the die plate.

[0013] The sliding member may be adapted to engage with the guiding pin when the actuator is actuated. In the present embodiment, the inclined head of the guiding pin resembles a cam profile portion at the distal end, which is adapted to engages with the inclined opening of the sliding member. Specifically, the opening of the sliding member has an angular edge profile corresponding to the inclined head of the guiding plate such that the guiding pin positively fits inside the inclined opening of the sliding member.

[0014] During the primary stage of moulding, the primary ejection plate and the secondary ejection plate moves towards the die plate (a first stroke) and retracts to an initial position near the lower fixing plate. During the secondary stage, the primary ejection plate has to be disengaged with the secondary ejection plate for a second stroke. In the second stroke, the primary ejection plate disengages with the secondary ejection plate and moves towards the die plate to carry out a secondary ejection process, thereby completing the moulding process.

[0015] In the present embodiment, upon actuation of an actuator, the primary ejection plate and the secondary ejection plate moves together in a first direction. Simultaneously, the sliding member moves in the first direction and subsequently in a second direction. The second direction is substantially perpendicular to the first direction along the horizontal plane. When the sliding member moves in the second direction, at least one engaging portion disengages from the first opening of the primary ejection plate thereby disengaging the primary ejection plate from the secondary ejection plate.

[0016] More specifically, engagement of the inclined head of the guiding pin with the inclined opening of the sliding member facilities the sliding member to move in the second direction. When the sliding member moves in the second direction towards the guiding plate, the engaging portion of the sliding member disengages from the locking surface of the primary ejection plate such that the primary ejection plate can move independently without the secondary ejection plate to carry out the secondary ejection process.

[0017] Similarly, in another embodiment, upon actuation of the actuator, the sliding member along with the primary ejection plate and the secondary ejection plate moves in a first direction towards the guiding pin arranged in the lower fixing plate in a Z-axis. When the inclined head of the guiding pin engages with the engaging portion of the sliding member, the engaging portion of the sliding member disengages from the locking surface of the primary ejection plate such that the primary ejection plate can move independently without the secondary ejection plate to carry out the secondary ejection process.

[0018] The moulding apparatus further includes a stopper assembly to stop the further movement of the secondary ejector assembly along with the primary ejector assembly. The stopper assembly is an elongated piston-like member which is connected to the die plate. When the ejection plates move in the first direction, the stopper assembly engages with the secondary ejection plate and restricts the further movement of the secondary ejection plate. When the stopper assembly engages with the secondary ejection plate, the primary ejection plate moves towards the die plate for completing the second stroke and thereby completing the moulding process.

[0019] Further, the moulding apparatus includes a sleeve assembly with sleeve pins and ejector pins. The secondary ejection plate has sleeve pins configured thereon, and the primary ejection plate has ejector pin assembled thereon. When the secondary ejection plate having the sleeve pins stops, the primary ejection plate having the ejector pins moves further to de-mould the part completely from the core block.

Brief Description of the Drawings

[0020] Other features and advantages of the invention will become apparent when reading the detailed description given below, purely by way of example and in a non-limitative manner, referring to the following figures:

[0021] Figure 1 shows a schematic representation of a double ejection mechanism for an injection moulding apparatus in accordance with the present invention;
[0022] Figure 2 shows a schematic representation of a guiding plate arrangement on a lower fixing plate;

[0023] Figure 3 illustrates a schematic representation of a guiding plate movement inside a sliding plate and ejection plates;

[0024] Figure 4a illustrates a schematic representation of the apparatus with ejection plates in a retracted position;

[0025] Figure 4b illustrates a schematic representation of the apparatus with ejection plates with the guiding plate in an engaged position with the sliding plate;

[0026] Figure 4c illustrates a schematic representation of the apparatus with a primary ejection plate being disengaged from the secondary ejection plate;

[0027] Figure 5 illustrates a second embodiment of the apparatus with the guiding plate arranged on the lower fixing tool; and

[0028] Figures 6a, 6b and 6c illustrate a schematic representation of a primary ejection plate, a sliding member and a secondary ejection plate.

Detailed Description of the Invention
[0029] An embodiment of this invention, illustrating its features, will now be described in detail. The words "comprising, "having, "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open-ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items or meant to be limited to only the listed item or items.

[0030] The terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the terms “an” and “a” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

[0031] The disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms.

[0032] A double injection moulding apparatus consists of two segments, like a lower fixing plate and a die plate. The lower fixing plate has an injection nozzle attached to it, whereas a die plate has a cavity corresponding to an article with the lower fixing plate that is capable of moving relative to the fixing plate. An ejector assembly is provided between the fixing plate and the die plate that has an ejector pin and an ejector sleeve. In double ejection moulding apparatus, the ejector assembly includes a primary ejection plate and a secondary ejection plate.
[0033] In double ejection moulding, the moulding is carried out in two stages, a primary process and a secondary process. The primary process includes the movement of both the ejection plate, whereas, in the secondary process, the primary ejection plate has to complete an additional stroke than the secondary ejection plate to complete the secondary process.

[0034] Referring now to figure 1, a moulding apparatus (100) in accordance with the present invention is illustrated. The apparatus (100) includes an ejection unit (200) consisting of a primary ejection plate (110) and a secondary ejection plate (120). Both the primary ejection plate (110) and the secondary ejection plate (120) are arranged horizontally to a lower fixing plate (300) and a die plate (400). The primary ejection plate (110) resides on an upper portion to the secondary ejection plate (120). Specifically, the primary ejection plate (110) is adjacent to the die plate (400), and the secondary ejection plate (120) is adjacent to the lower fixing plate (300).

[0035] In the present embodiment, the primary ejection plate (110) and the secondary ejection plate (120) are engageably connected by a sliding member (130). Both the ejection plates (110, 120) are having a first and a second opening (110a, 120a) respectively corresponding to each other. The sliding member (130) is slidably arranged inside the primary ejection plate (110) and the secondary ejection plate (120). Specifically, the sliding member (130) is slidably arranged inside the first and the second openings (110a, 120a) of the primary ejection plate (110) and the secondary ejection plate (120). The sliding member (130) has atleast one engaging portion (132) adapted to engage the primary ejection plate (110) with the secondary ejection plate (120). The primary ejection plate (110) has a locking surface (112) inside the opening (110a) corresponding to the engaging portion (132) of the sliding member (130). The locking surface (112) of the primary ejection plate (110) sequentially engages or disengages with the engaging portion (132) according to the movement of the sliding member (130). The sliding member (130) has an inclined opening (130a) corresponding to the openings (110a, 120a) of the ejection plates (110, 120) as shown in figure 6c. Specifically, the openings (110a, 120a) of the ejection plates (110, 120) and the opening (130a) of the sliding member (130) are in-line with each other. The primary ejection plate (110) has ejector pins assembled thereon, and the secondary ejection plate (120) has sleeve pins configured on it.

[0036] Further, referring to figures 4a, 4b and 4c, the moulding apparatus (100) is provided with a guiding pin (140). In a first embodiment, as shown in figure 1, the guiding pin (140) is arranged perpendicularly in between the die plate (400) and the lower fixing plate (300). The guiding pin (140) is attached to a core block (410) of the die plate (400). Specifically, a proximal end of the guiding pin (140) is connected to the die plate (400), and a distal end is engageably connected to the sliding member (130). The guiding pin (140) is a cam-shaped arrangement with an inclined head (141) arranged on the core block (410) of the die plate (400) as shown in figure 1. The proximal end of the guiding pin (140) is connected to the core block (410). In a second embodiment, the guiding pin (140) is arranged at the lower fixing plate (300) as shown in figure 2, and one end of the guiding pin (140) engages with the sliding member (130) to facilitate a linear movement.

[0037] During a primary stage of moulding, both the primary ejection plate (110) and the secondary ejection plate (120) are engaged together and moves relative to each other towards the die plate (400) as shown in figure 4a. The moulding apparatus (100) has a hydraulic actuator (500) for actuating the “to” and “fro” movement of the primary and the secondary ejection plates (110, 120) between the lower fixing plate (300) and the die plate (400).

[0038] The sliding member (130) is adapted to engage with the guiding pin (140) when the actuator (500) is actuated. In the present embodiment, as shown in figure 1, the inclined head (141) of the guiding pin (140) resembles a cam profile portion which is adapted to engage with the inclined opening (130a) of the sliding member (130). Specifically, the inclined opening (130a) of the sliding member (130) has an angular edge profile corresponding to the inclined head (141) of the guiding pin (140) such that the guiding pin (140) positively fits inside the inclined opening (130a) of the sliding member (130) as shown in figure 3.

[0039] During the primary stage of moulding, the primary ejection plate (110) and the secondary ejection plate (120) moves towards the die plate (400) (a first stroke) and retracts to an initial position near the lower fixing plate (300). During the secondary stage, the primary ejection plate (110) has to be disengaged with the secondary ejection plate (120) for a second stroke. In the second stroke, the primary ejection plate (110) disengages with the secondary ejection plate (120) and moves towards the die plate (400) to carry out a secondary ejection process thereby completing the moulding process.

[0040] In the present embodiment as shown in figures 4a, 4b and 4c, upon actuation of the actuator (500), the primary ejection plate (110) and the secondary ejection plate (120) moves together in a first direction 100a. Simultaneously, the sliding member (130) moves in the first direction (100a) and subsequently in a second direction (100b). The second direction (100b) is substantially perpendicular to the first direction (100a) along the horizontal plane. When the sliding member (130) moves in the second direction (100b), the engaging portion (132) disengages from the first opening (110a) of the primary ejection plate (110) thereby disengaging the primary ejection plate (110) from the secondary ejection plate (120).

[0041] More specifically, engagement of the inclined head (141) of the guiding pin (140) with the inclined opening (130a) of the sliding member (130) facilities the sliding member (130) to move in the second direction (100b). When the sliding member (130) moves in the second direction (100b), the engaging portion (132) of the sliding member (130) disengages from the locking surface (112) of the primary ejection plate (110) such that the primary ejection plate (110) can move independently without the secondary ejection plate (120) to carry out the secondary ejection process as shown in figure 4c.

[0042] Similarly, in the second embodiment as shown in figures, 2 and 5, upon actuation of the actuator (500) the sliding member (130) along with the primary ejection plate (110) and the secondary ejection plate (120) moves in a first direction (100a) towards the guiding pin (140) arranged in the lower fixing plate (300) in a Z-axis. When the inclined head (141) of the guiding pin (140) engages with the engaging portion (132) of the sliding member (130), the engaging portion (132) disengages from the locking surface (112) of the primary ejection plate (110) such that the primary ejection plate (110) can move independently without the secondary ejection plate (120) to carry out the secondary ejection process.

[0043] The moulding apparatus (100) further includes a stopper assembly (150) to stop the further movement of the secondary ejection plate (120) along with the primary ejection plate (110). The stopper assembly (150) is an elongated piston-like member which is connected to the die plate (400). When the ejection plates (110, 120) moves in the first direction (100a), the stopper assembly (150) engages with the secondary ejection plate (120). When the stopper assembly (150) engages with the secondary ejection plate (120), it restricts the further movement of the secondary ejection plate (120). When the stopper assembly (150) engages with the secondary ejection plate (120), the primary ejection plate (110) moves towards the die plate (400) for completing the second stroke and thereby completing the moulding process. Similarly, when the primary ejection plate (110) retracts to the initial position, the sliding member (130) engages with both the ejection plates (110, 120).

[0044] Depending on the length of the welding cylinder, the stroke of the sliding member (130) and subsequently, the angle of the inclined opening (130a) and the inclined head (141) is calculated. The moulding apparatus (100) further includes a sleeve assembly (600) with sleeve pins and ejector pins. The secondary ejection plate (120) has sleeve pins configured thereon, and the primary ejection plate has ejector pin assembled thereon. When the secondary ejection plate (120) having the sleeve pins stops, the primary ejection plate (110) having the ejector pins moves further to de-mould the moulded part completely from the core block (410).

[0045] Therefore, the present invention has the advantage of providing a double ejection apparatus (100) which has a simple design and is durable during continuous production of mould. The apparatus (100) is economical and robust in construction and can be manufactured easily. Further, the injection moulding apparatus (100) can be easily operated.

[0046] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the scope of the claims of the present invention.