Piston for cold-chamber injection machines

Abstract

A PISTON FOR COLD-CHAMBER INJECTION MACHINES comprising a support (2) and an external body (3) with a sealing ring (5), joined by a bayonet lock ring (6) independent of the external body (3) and divided into two parts (6a) fitted onto a groove (21) in the support (2) and connected by long screws (7) inserted into threaded holes (61). The piston preferably includes a spring bush (4) as a part that adjusts to the container, independent of the external body (3) and of the bayonet lock ring (6), under which a conical spring ring (8) is included which exerts pressure on the two parts that form the bush (4), tending to expand the same. The piston also includes alternating transverse grooves (81) along the edges thereof for receiving conical metal tips (9) inserted through holes (63) in the bayonet lock ring (6).

Claims

1. A piston for cold-chamber injection machines, which is applicable in injection machines with cylinder containers, and designed to move fitted to the walls of the cylinder container or sleeve, comprising, connected through at least one grub screw (10), a support (2) and an external body (3), characterised in that it includes a bayonet lock ring (6), to complement the fastening between the external body (3) and the support (2), said bayonet lock ring (6) constituting an independent piece of the external body (3).

2. The piston for cold-chamber injection machines, according to claim 1, characterised in that the bayonet lock ring (6) is divided into two semicircular parts (6a) that are joined to each other, and suitable to being fitted onto a groove (21) provided for this purpose in the support (2), through two long screws (7) inserted in threaded holes (61) made for this purpose in both parts of the ring.

3. The piston for cold-chamber injection machines, according to claim 1 or 2, characterised in that the bayonet lock ring (6) has four recesses (62) therein arranged to correspond with respective protuberances (22) of the support (2) itself.

4. The piston for cold-chamber injection machines, according to claim 1, characterised in that it includes a spring bush (4) as a piece that adjusts to the walls of the container, consisting of an independent piece of the external body (3) and the bayonet lock ring (6).

5. The piston for cold-chamber injection machines, according to claim 4, characterised in that, below the spring bush (4) and on the external body (3), it includes a conical spring ring (8), which exerts pressure on the bush (4) tending to expand the same.

6. The piston for cold-chamber injection machines, according to claim 5, characterised in that the spring ring (8) has a series of transverse grooves (81) made alternately on the edges thereof that, once inserted between the external body (3) and the bush (4), are what make it tend to press outwards on said bush (4).

7. The piston for cold-chamber injection machines, according to claim 6, characterised in that the transverse grooves (81) of the spring ring (8), at least those provided on the wide edge of the ring, are suitable for receiving conical metal tips (9) that are inserted therein through holes (63) provided for this purpose in the bayonet lock ring (6).

Description

DESCRIPTION OF THE DRAWINGS

(1) As a complement to the description provided herein, and for the purpose of helping to make the characteristics of the invention more readily understandable, the present specification is accompanied by a set of drawings constituting an integral part of the same, which, by way of illustration and not limitation, represent the following:

(2) FIG. 1 shows a perspective exploded view of a exemplary embodiment of the piston for cold-chamber injection machines, in which the pieces and elements which it comprises, as well as the configuration of each of them may be seen.

(3) FIG. 2 shows a side elevation view, with a partial cross section, of the exemplary piston, according to the invention shown in the previous figure, shown in this case once all the pieces and elements which it comprises are mounted; and

(4) FIG. 3 shows a perspective view of the bayonet lock ring that the piston of the invention includes, showing the two parts that make it up and the configuration thereof.

PREFERRED EMBODIMENT OF THE INVENTION

(5) In light of the aforementioned figures and in accordance with the adopted numbering, one may observe therein an example of a preferred, non-limiting embodiment of the piston for cold-chamber injection machines of the invention, which comprises the parts and elements that are indicated and described in detail below.

(6) Thus, as may be seen in said figures, the piston (1) in question, that conventionally comprises a support (2) to which an external body (3) is coupled, upon which, in turn, a spring bush (4) is preferably included and a sealing ring (5) has the particular feature of having a bayonet lock ring (6) in order to achieve the fastening between said external body (3) and the support (2).

(7) As has previously been explained, the support (2) links the piston (1) with the mechanisms of the machine that provides the movement thereto adjusted inside the container (not shown) in order to push the liquid metal to be injected, and cooling fluid is inserted through said support (2) inside the external body (3), which is hollow, to reduce the effects of the heat of the liquid metal thereon, transferring it to the bush (4) which is the piece that suffers most wear due to being the one that, as well as the sealing ring (5), adjusts to the walls of the container in order to achieve the vacuum therein, in this case being an independent piece of the external body (3) and the bayonet lock ring (6).

(8) In FIGS. 1 and 3 it may be seen how said bayonet lock ring (6) is divided into two semicircular parts (6a) that are joined to each other, fitted onto a groove (21) provided for this purpose in the support (2), via two long screws (7) inserted into threaded holes (61) made for this purpose in both parts of the ring itself.

(9) Likewise, said figures shows the inner configuration of the bayonet lock ring (6) which has four recesses (62) that correspond with respective protuberances (22) of the aforementioned groove (21) of the support (2) into which it fits.

(10) At the same time, the spring bush (4), which in a preferred embodiment of the invention is an independent piece of the external body (3), and includes, below the same and on the external body (3), a conical spring ring (8), as seen in FIG. 2, which exerts pressure on the bush (4), tending to expand the same.

(11) In order to do so, this spring ring (8) has a series of transverse grooves (81) made alternately on the edges thereof that, as well as providing an expansive effect, thus meaning that once it is inserted between the external body (3) and the bush (4) it tends to press outwards on said bush (4), being suitable, at least those provided in the wide edge of the ring, for receiving the conical metal tips (9) that are inserted therein through holes (63) provided for this purpose in the bayonet lock ring (6).

(12) Lastly it must be mentioned that at least one cut-out (64) is provided in the bayonet lock ring (6) that, located to coincide with another complementary cut-out (23) of the support (2), is intended to facilitate the passage of the head of a grub screw (10) that conventionally complements the fastening of the assembly.

(13) Having thus adequately described the nature of the present invention, as well as how to put it into practice, it is deemed unnecessary to make this description any longer in order for anyone skilled in the art to understand the scope of the invention and the advantages deriving therefrom. It must be noted that, within its essential nature, the invention may be carried out according to other embodiments differing in detail from that set out by way of example, which the protection sought would equally cover, provided that the fundamental principle thereof is not altered, changed or modified.