|
(11) | EP 2 436 460 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 153(4) EPC |
|
|
|
|
|||||||||||||||||||
| (54) | MOULD FOR MAKING BALLS WITH INTEGRAL SHAFTS FOR VALVES BY CENTRIFUGAL MOULDING |
| (57) The present invention relates to a mould for making balls with integral shafts for
valves by centrifugal moulding, made up of two complementary half-bodies (1 and 2)
which are assembled and placed on a rotary mount, each of said half-bodies (1 and
2) forming, inside, a central cavity (5) from which there extend channels (6), such
that the two half-bodies (1 and 2) between them define a central receptacle with the
shape of the ball bodies to be moulded and ducts for forming the shafts associated
with said ball body. |
Field of the Art
[0001] The present invention relates to making balls for the ball valves used in fluid ducts, proposing a mould of particular features for making said balls by means of centrifugal moulding.
State of the Art
[0002] The movable element of the ball valves which are arranged in fluid ducts consists of a metal ball provided with a transverse hole incorporating one or two protruding radial shafts projecting from the ball perpendicular to said hole.
[0003] Said ball valve metal balls are conventionally made by moulding in a stationary mould, which has the drawback that the ball manufacturing material contracts as it solidifies, leaving defective areas on the outside of the ball due to lack of material, such that for making the spherical surface of the ball uniform adding a filling material supplement in the defective areas is necessary, involving a second operation with a loss in time and increase in cost.
[0004] On the other hand, centrifugal moulding consisting of using a mould arranged in a rotary mount and associated with an operating device is known in making cylindrical tubes, such that by rotating the mould while at the same time pouring the moulding material into the mould, the moulded material adapts perfectly to the wall of the mould, solidifying in correspondence with said wall without the solidification contraction causing defects on the surface of the moulded part.
Object of the Invention
[0005] According to the invention, a mould designed for making ball valve balls by means of the centrifugal moulding system is proposed, said mould being developed with constructive and functional features making it particularly advantageous for said function.
[0006] This mould object of the invention comprises two complementary half-bodies correspondingly coupled to each other, one of the half-bodies being arranged on a support defining a rotary mount of said half-body, having a coupling with a rotary operation driving device, while the other half-body has an inlet for introducing the material to be moulded into the mould.
[0007] Between the two component half-bodies of the mould, they form, inside, a central cavity with the shape of the balls to be made, said cavity being prolonged with two cylindrical ducts extending in opposite directions along the mould.
[0008] A mould is thereby provided which allows making the balls for the ball valves by centrifugal moulding by means of its rotary operation, the ball bodies being able to be formed with the corresponding shaft or shafts already integrated.
[0009] The shaft or shafts which are to be integrated in the ball can be obtained in the mould together with the ball which is moulded by means of the same ball forming material, but prefabricated shafts can also be incorporated, placing them in the longitudinal ducts of the mould, such that when moulding the ball said shafts are integrated with the ball forming material.
[0010] Accordingly, sealing accessory parts combined with the mould are provided, which parts can be placed at the beginning of the longitudinal ducts of the mould for flush-closing said ducts, when necessary, of the central cavity for forming the ball, balls integrated with one or with two shafts, as well as balls alone, without any shaft, thus being able to be moulded, sealing the longitudinal ducts of the mould or leaving them open, as required in each case.
[0011] Said mould object of the invention therefore has certainly advantageous features, acquiring its own identity and preferred character for the intended ball moulding function.
Description of the Drawings
[0012]
Figure 1 shows a schematic depiction of a mould according to the object of the invention.
Figure 2 is a sectioned view of the mould with the two component half-bodies separated from one another.
Figure 3 is a sectioned view of the mould closed.
Figure 4 is a sectioned view of the mould closed with a sealing accessory part in one of the longitudinal ducts on the inside.
Figure 5 is a sectioned view of the mould closed with a sealing accessory part in one of the longitudinal ducts on the inside and a prefabricated shaft in the other longitudinal duct.
Figure 6 is a top plan view of the lower half-body of the mould, with a sealing accessory part in one of the longitudinal ducts on the inside.
Detailed Description of the Invention
[0013] The object of the invention relates to a mould designed for making the balls forming the movable element of the ball valves which are arranged in fluid ducts, with an embodiment of said mould provided for centrifugal moulding.
[0014] The proposed mould comprises a correspondingly complementary lower half-body (1) and upper half-body (2), the lower half-body (1) being placed in a rotary mount, for example on a circular rolling support (3) or any other means allowing a rotational movement actuated by a rotary operating mechanism (4).
[0015] Each of the half-bodies (1 and 2) forming, inside, a central cavity (5) formed according to the shape of one half of the balls to be made, starting from said central cavity (5) in opposite directions there being two semi-cylindrical channels (6) extending in the longitudinal direction of the corresponding half-body (1 or 2).
[0016] Thus, when the two half-bodies (1 and 2) are attached by their opposing faces, between the central cavities (5) thereof they define a receptacle with the shape of the ball bodies to be made, whereas between the channels (6) they define cylindrical ducts extending radially from the aforementioned central cavity.
[0017] One of the half-bodies, preferably the upper half-body (2), has in connection with the cavity (5) of the inner part an opening (7), through which the liquid material designed to be moulded to form therewith the balls to be made can be introduced.
[0018] The moulding is done by introducing through the opening (7) the material designed for forming the balls, while at the same time the mould is rotated, whereby the moulding material adapts to the wall of the central receptacle defined by the complementary cavities (5), solidifying in correspondence with said wall, such that the outer surface of the moulded part has the shape defined by the aforementioned receptacle, without deformations due to contraction of the material as it solidifies.
[0019] In one of the half-bodies of the mould, preferably the lower half-body (1), the channels (6) have holes (8), whereby a sealing accessory part (10) for sealing the cylindrical duct formed by the corresponding channels (5) can be fastened with screws (9).
[0020] By means of sealing the two cylindrical ducts defined by the channels (6) of the half-bodies (1 and 2) with respective sealing accessory parts (10), parts can thus be moulded with the shape of only the ball bodies, whereas by sealing one of the cylindrical ducts and leaving the other one open, as in Figure 4, parts can be moulded with the shape of the ball bodies and a radial shaft projecting therefrom, whereas by leaving the two cylindrical ducts open, as in Figure 3, parts can be defined with the shape of the ball bodies and two opposite shafts projecting therefrom.
[0021] In connection with the ball bodies which are moulded, one or two shafts can be formed by means of the same ball body forming material, leaving one or both cylindrical ducts inside the mould open as previously indicated, but also, as can be seen in Figure 5, a prefabricated shaft (11) can be placed in the cylindrical duct in which a shaft is to be obtained, which shaft becomes integrally attached with said ball body of the prefabricated shaft (11) as the ball body forming material is moulded, a smaller amount of material to be moulded therefore being needed.
1. A mould for making balls with integral shafts for valves by centrifugal moulding,
characterised in that it comprises two half-bodies (1 and 2) which are correspondingly coupled to each
other, assembled and placed on a rotary mount linked to an operating mechanism (4),
each of the half-bodies (1 and 2) in the coupling face forming a central cavity (5)
from which there extend semi-cylindrical channels (6) in opposite directions, such
that in the coupling of the aforementioned half-bodies (1 and 2) between them they
define a central receptacle with the shape of the ball bodies to be moulded and cylindrical
ducts for forming shafts associated with the ball bodies to be moulded.
2. The mould for making balls with integral shafts for valves by centrifugal moulding
according to claim 1, characterised in that flush sealing accessory parts (10) of the central receptacle are arranged in connection
with one or both inner cylindrical ducts of the mould for preventing the entry of
the moulding material in those cylindrical ducts.
3. The mould for making balls with integral shafts for valves by centrifugal moulding
according to claim 1, characterised in that prefabricated shafts (11) are arranged in connection with one or both inner cylindrical
ducts of the mould for integrating said shafts with the ball body forming material
which is moulded in the central receptacle.