AN APPARATUS FOR MAKING MOULD PARTS WITH A HORIZONTAL PARTING FACE

Abstract: A apparatus for making mould parts with a horizontal parting face consists of a container (1) in which is kept moulding material (2), preferably moulding sand, a moulding chamber (3) which may be subjected to vacuum and which may be defined at the bottom by a pattern plate (4) and at the top by a squeeze plate (5). Moulding material (2) is impulsively sucked into the moulding chamber (3) through the squeeze plate (5) and is post-compacted in it by advancing the squeeze plate (5) with the pattern plate (4), which carries a half pattern. The moulding material (2) is sucked into the moulding chamber (3) through a slot (6) placed centrally in the squeeze plate (5). The container (1) is tapered in V-shape at the bottom (7) in the direction of the slot (6) in its entire longitudinal direction. One or more air intake openings (8) are provided on the tapered side faces of the container (1). The air flow across the oblique container side faces towards the bottom slot (6) reduces the friction between the moulding material and the container in the inlet.

Description: An apparatus for making mould parts with a horizontal parting face. TECHNICAL FIELD The invention relates to an apparatus for making mould parts with a horizontal parting face and of the type that includes a container for the moulding material, preferably moulding sand, a moulding chamber which may be subjected to vacuum, and which may be defined at the bottom by a pattern plate and at the top by a squeeze plate, whereby the moulding material is impulsively sucked into the moulding chamber through the squeeze plate and is post-compacted in it by advancing the squeeze plate with the pattern plate, which carries a half pattern. BACKGROUND ART In this type of apparatus, the moulding sand tends to bridge and clot in the inlet to the moulding chamber due to internal friction in the moulding material and to its friction against the walls of the container. Attempts have been made to overcome the disadvantages by using a funnel-shaped inlet connecting the container with inlet openings in the squeeze plate above the moulding chamber, and by providing- fluidization of the funnel-shaped inlet by applying pressure through nozzle filters in the funnel sides. An apparatus of this type is described in the Danish patent application No. 2945/84. DISCLOSURE OF THE INVENTION However, it has been found that the nozzle filters tend to block when using comparatively dry moulding mate¬ rial, and the positive supply of pressurized air is a complex measure making the apparatus more expensive. The object of the invention is to provide an apparataus of the type referred to in the opening paragraph, where the danger of blocking and bridging in the inlet to the moulding chamber has been eliminated, at the same time as satisfactory filling and compaction of the moulding material are achieved in the moulding chamber. According to the invention, this object is achieved by an apparatus of the type described in the opening paragraph characterized in that the moulding material is sucked into the moulding chamber through a slot placed centrally in the squeeze plate, and that the bottom of the container is tapered in V-shape in the direction of the slot in its entire longitudinal direc¬ tion, whereby one or more air intake openings are provided on the tapered side faces of the container. It has been found that the amount of air sucked in due to the vacuum in the moulding chamber generates an air cushion, which reduces friction in the inlet and "rin¬ ses" the oblique, tapered sides of the container. Pro- viding one slot ensures maximum moulding material flow by time unit, as the moulding material will flow lami- narly through the slot in the same way as in the case of unobstructed emptying from a bag-shaped orifice. According to the invention, the slot may have a length and a width corresponding to the moulding chamber, ranging from 30 to 90 mm, preferably 55 mm. Experiments have shown that particul arly exce l l ent fi l l ing is obtained when s lot widths are kept within this interval , and a s lot width of 55 mm is particul ar¬ ly advantageous. In a preferred embodiment of an apparatus according to the invention, screen pl ates are pl aced above the air intake openings on the side faces pl aced opposite each other in the container bottom tapered in V- shape, while forming side slots some distance above the bottom slot. By pl acing screen pl ates, the danger of blocking the intake openings is eliminated, and a slot is formed, so that the sucked-in air can be directional ly led across the obl ique container side faces, preferably towards the slot in the bottom of the container. The friction- reducing rinsing effect is increased by this measure. BRIEF DESCRIPTION OF THE DRAWING The invention wi l l be described in more detai l be l ow with reference to the drawing, whose single figure gives an oblique schematic view of an apparatus desig- ned according to the invention. DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus inc l udes a container 1 for keeping the moulding material 2, preferably moulding sand. In the embodiment shown in the drawing, the apparatus is used for simultaneous making of two matching mould parts in an upper and a l ower moul ding chamber, the bottom moulding chamber connecting with the container 1 via an L-shaped down pipe. The lower moulding chamber and the L-shaped down pipe are however not a prerequi- site for the invention and wi l l consequent ly not be described in more detail . Below the container 1 there is a moulding chamber 3, at its top defined by a squeeze plate 5 and at the bottom designed for closing against a pattern plate 4, which, as indicated, may be removed from the area below the 5 moulding chamber for pattern plate replacement. The container 1 connects with the moulding chamber 3 through an inlet tapered in V-shape at the bottom 7 of the container. The tapered inlet merges into a slot 6 in the squeeze plate 5. The slot has a length L, equal 10 to the length of the moulding chamber, and a width W, preferably in the area from 30 to 90 mm. In the side faces of the container tapered in V-shape there are air intake openings 8, in the shown embodi¬ ment covered by a screen plate 9 internally in the 15 container. Between the screen plate 9 and the container wall, there are air slots 10, from which the air is led towards the slot 6 across the bottom side face 7. In the embodiment shown in the drawing, four circular openings 8 are provided at each container side. Of 20 course it is within the concept of the invention to provide a different number of holes and differently shaped holes, and it might be advantageous to use one slot instead of several openings. What is decisive is simply to provide a suitable pressure drop across the 25 openings and thus sufficient speed in the air flowing from the side slot 10 to the bottom slot 6. It is moreover within the concept of the invention to apply a smaller positive pressure to the openings 8, as the intended effect is achieved due to the pressure 30 difference between the area behind the side slots 10 and the moulding chamber 3 under vacuum. The moulding material is compacted in the moulding chamber by sucking in secondary air from the area above the moulding material in the container, down through the moulding material and out through the openings through which the vacuum is applied. The primary air intake through the openings 8 will speed up compaction, as this primary air flow is added to the secondary air flow.

Claims: CLAIMS 1. An apparatus for making mould parts with a hori¬ zontal parting face, including a container (1) for the moulding material (2), preferably moulding sand, a moulding chamber (3), which may be subjected to vacuum and which may be defined at the bottom by a pattern plate (4) and at the top by a squeeze plate (5), where¬ by the moulding material (2) is impulsively sucked into the moulding chamber (3) through the squeeze plate (5) and is post-compacted in it by advancing the squeeze plate (5) with the pattern plate (4), which carries a half pattern, c h a r a c t e r i z e d in that the moulding material (2) is sucked into the moulding cham¬ ber (3) through a slot (6) placed centrally in the squeeze plate (5), and that the container (1) is ta¬ pered in V-shape at the bottom (7) in the direction of the slot (6) in its entire longitudinal direction, whereby one or more air intake openings (8) are pro¬ vided on the -tapered side faces of the container (1). 2. An apparatus according to claim 1, c h a r a c¬ t e r i z e d in that the slot (6) has a length (L) and a width (W) corresponding to the moulding chamber (3) ranging from 30 to 90 mm, preferably 55 mm. 3. An apparatus according to claim 1, c h a r a c- t e x i z e d in that screen plates (9) are placed above the air intake openings (8) on the side faces placed opposite each other in the V-shaped tapered container bottom (7), while forming side slots (10) placed some distance above the bottom slot (6).

Inventors: JENSEN CLAUS TORBEN, JOHANSEN JOERN E, KAUSERUD HAAKON, JENSEN, CLAUS, TORBEN, JOHANSEN, JOERN, E., KAUSERUD, HAAKON
Applicants: DANSK IND SYNDIKAT, DANSK INDUSTRI SYNDIKAT A/S
Application year: 1987
Main classification: B22C15
IPC codes: B22C11, B22C15, B28B1, B28B13