EP3321052A1

EP3321052A1 - Device with improved ejectors and method therefor

Info

Publication number: EP3321052A1
Application number: EP17192092.9A
Authority: EP
Inventors: Hubertus Antonius Maria Jans
Original assignee: Beheermaatschappij De Boer Nijmegen BV
Current assignee: Beheermaatschappij De Boer Nijmegen BV
Priority date: 2016-10-25
Filing date: 2017-09-20
Publication date: 2018-05-16
Anticipated expiration: 2037-09-20
Also published as: EP3321052B1; DK3321052T3; NL2017672B1; ES2748878T3

Abstract

The present invention relates to a device, comprising:
- a mould container (1) with at least one mould cavity (6);
- at least one ejector (40) per mould cavity, comprising:
- a bottom (42) of the mould cavity (6) which is movable in the mould cavity for the purpose of ejecting a green brick formed in the mould cavity;
- an ejector shaft (44) extending from the bottom (42) of the mould cavity through a bottom of the mould container (1) and having a support (50) extending radially outward from the ejector shaft (44);
- a spring (66) which is tensioned between the support (50) of the ejector shaft (44) and the bottom of the mould container (1);

- wherein an inner diameter of the spring (66) has a larger dimension than the support (50); and
- wherein an adapter (74) is provided which is arranged between the support (50) and the spring (66), wherein the adapter (74) is provided with a radial passage (78) with which the adapter (74) can be arranged round the ejector shaft (44) in a lateral direction.

The invention further relates to a method for arranging such an ejector (40) in a mould cavity (6) of a mould container (1).

Description

The invention relates to a device with improved ejectors for pressing out of a mould cavity of a mould container a green brick formed in the mould cavity, and a method therefor.
In so-called mould container presses, to which the present invention relates, deformable clay is pressed in mould cavities (usually covered with sand). The green brick formed in the mould cavity is then released in order to be dried and fired. Such a mould container press comprises a chain conveyor, also referred to as mould conveyor, which is assembled from a large number of mutually connected mould containers. Each mould container generally comprises a plurality of mould cavities in which the green bricks are formed. Ejectors are arranged in each mould cavity for the purpose of pressing the green brick out of the respective mould cavity. Such ejectors are subject to wear and must therefore be regularly replaced with new ejectors. Partly due to the large number of ejectors per mould conveyor, this is a labour-intensive and time-consuming repair, wherein the mould conveyor cannot be employed for the production of bricks for a considerable length of time. A mould container press with 30 mould cavities per mould container, which comprises a total of 50 mould containers, for instance has no less than 1500 ejectors.
The European patent EP-B 1-2242627 of applicant describes a device wherein the ejectors can be preassembled in a workshop, wherein the mould container comprises openings through which it is possible to displace an ejector with its ejector shaft with spring and stop arranged therearound, and wherein an intermediate member is provided between the spring and the opening in the mould container. Because an assembled ejector can be displaced through the opening in the mould container, this ejector can already be preassembled elsewhere.
Although the ejectors described in EP-B 1-2242627 already realized a significant time-saving in repair or replacement operations, it was found that these ejectors had only limited applicability in practice. As described above, a mould conveyor consists of a large number of mutually connected mould containers. Due to the presence of a deep recess, it is not possible to arrange the intermediate members according to EP-B 1-2242627 at the position of the connections between the mould containers, which are provided at both outer ends of a mould container. As a result, it is not possible to apply a preassembled ejector according to EP-B1-2242627 at these positions, but an ejector has to be assembled in situ, as was usual prior thereto. This results in a labour-intensive method which may moreover introduce an adjusting inaccuracy due to the adjustment of a cap nut.
In practice this labour-intensive method has to be applied for a large number of positions. In the given example of a mould container with 30 mould cavities 3 or 4 positions at both outer ends lie in a deeper recess. Starting from the most positive situation of 3 positions at both outer ends, thus 6 in total per mould container, 6 of the 30 positions, i.e. 20%, are unusable. In the case of mould containers with fewer than 30 mould cavities the number of positions in a deeper recess is even higher in terms of percentage.
There is a need for an improved device which can be applied at all positions, including the 20% or more positions where a deep recess is present.
DE 10 73 926 is the most closely related prior art, and at least the measures of the characterizing part of claim 1 are new relative thereto. EP 1 112 827 and DE 28 08 284 are recognized as further prior art.
An object of the present invention is to provide a device and method wherein said drawbacks do not occur, or at least do so to lesser extent.
Said object is achieved according to the invention with the device according to claim 1 and the method according to claim 12.
The device according to the invention comprises:

a mould container with at least one mould cavity;
at least one ejector per mould cavity, comprising:
- a bottom of the mould cavity which is movable in the mould cavity for the purpose of ejecting a green brick formed in the mould cavity;
- an ejector shaft extending from the bottom of the mould cavity through a bottom of the mould container and having a support extending radially outward from the ejector shaft;
- a spring which is tensioned between the support of the ejector shaft and the bottom of the mould container;
wherein an inner diameter of the spring has a larger dimension than the support; and
wherein an adapter is provided which is arranged between the support and the spring, wherein the adapter is provided with a radial passage with which the adapter can be arranged round the ejector shaft in a lateral direction.

Because the inner diameter of the spring has a larger dimension than the support, which is itself thickened relative to the ejector shaft, the spring can be arranged over the support and to a position round the ejector shaft. By then arranging an adapter between the support and the spring, the spring is enclosed with the adapter between the support and the bottom of the mould container. The support of the ejector shaft can be easily reached for all mould cavity positions, including for positions close to the outer ends of the mould containers where the deep recesses are provided for which the method according to EP-B 1-2242627 is unsuitable.
The support is thickened relative to the ejector shaft in that the support extends radially outward from the ejector shaft. The adapter is provided with a radial passage with which the adapter can be arranged round the ejector shaft in a lateral direction. After the adapter has been slid round the ejector shaft in a lateral direction the spring is enclosed between the adapter lying against the support of the ejector shaft and the bottom of the mould container.
Because the adapter according to the invention lies against the thickened support which is arranged on the ejector shaft, the adapter can be easily arranged and removed at all possible positions. Ejectors can hereby be replaced in simple manner at all mould cavity positions. This is even the case for positions where the ejector extends through a relatively deep recess.
Despite the number of operations increasing relative to the prior art formed in EP-B1-2242627 , a time-saving is still achieved in that the operations can be automated to a large extent. According to the prior art, the spring has to be pulled away from the mould container in order to provide space between the mould container and the spring for placing the spring washer therebetween. In contrast to the inconvenient pulling on a spring, what is conversely necessary according to the invention is to compress the spring in order to provide space, at the end of the ejector shaft remote from the mould container, between the support of the ejector shaft and the spring for the purpose of placing an adapter therebetween. This compressing of the springs is easier than pulling away of such springs, and can thereby moreover be readily automated.
A further advantage is that the support can be fixedly mounted on the shaft in non-adjustable manner, whereby a well controllable (i.e. non-adjustable) dimensioning of the ejector shaft is obtained. This prevents a possible adjusting inaccuracy resulting from a cap nut tightened to greater or lesser extent, as is possible in the prior art formed by EP-B 1-2242627 .
The bottoms and ejector shafts can be assembled outside the mould container, for instance in a workshop. It is thus possible for the ejector shafts to be screwed into the bottoms and to be prepared and glued in a well controllable environment and with availability of tools equipped for this purpose in order to obtain a desired securing of the ejector shaft in the bottom. Glueing a screw thread connection between an ejector shaft and a bottom in situ and in a situation in which the ejectors are arranged in a mould container is very inconvenient as a result of the limited space available for the necessary preparation (cleaning, among other things) prior to the glueing. Screwing an ejector shaft through a mould container and fixedly into the bottom can moreover exert an undesired torque on the bottom, resulting in possible damage to the bottom. The screwing and glueing can be controlled well in a workshop, whereby reliable assemblies of bottoms and ejector shafts can be prepared.
The invention further relates to a method for arranging an ejector in a mould cavity of a mould container, comprising the steps of:

placing an ejector shaft of the ejector through an opening in a bottom of the mould container, wherein the ejector forms a bottom of the mould cavity and wherein the ejector shaft comprises a support extending radially outward from the ejector shaft;
sliding a spring, which has an inner diameter with a larger dimension than the support, over the support and to a position round the ejector shaft; and
arranging an adapter, which is provided with a radial passage with which the adapter can be arranged round the ejector shaft in a lateral direction, round the ejector shaft and between the support and the spring in a lateral direction.

Because the spring has a larger inner diameter than the support arranged on the ejector shaft, the spring can be slid over the support in simple manner during assembly. An adapter is then arranged between the support and the spring, wherein the adapter bridges the difference in dimension between the support and the spring and ensures that the spring is tensioned between the support and the bottom of the mould container.
Preferred embodiments form the subject-matter of the dependent claims.
Preferred embodiments of the present invention are further elucidated in the following description with reference to the drawing, in which:

Figure 1 is a cross-sectional view of a device according to the prior art formed by EP-B1-2242627 ;
Figure 2 is a perspective view of a part of a mould conveyor, wherein chain parts are shown with which two mould containers can be linked to each other, and wherein ejectors according to a first preferred embodiment are shown;
Figure 3 is a perspective cross-sectional view of the mould container of figure 2;
Figures 4 and 5 are cross-sectional views of two successive assembly steps of a device comprising a second preferred embodiment of an ejector according to the invention;
Figure 6 is a cross-sectional view of the first preferred embodiment of the ejector according to the invention, shown in a situation as according to figure 5;
Figure 7 is a perspective view of the situation of figure 6;
Figure 8 is a cross-sectional view of the first preferred embodiment of an ejector according to the invention, shown in a further assembly step;
Figure 9 is a perspective view of the situation of figure 8;
Figure 10A is a perspective view of the first preferred embodiment of an ejector according to the invention, shown in yet another assembly step;
Figure 10B is a perspective view of the adapter;
Figure 11 is a cross-sectional view of the first preferred embodiment of an ejector according to the invention, shown in yet another assembly step; and
Figure 12 is a perspective view of the situation of figure 11.

Prior art

Figure 1 shows a device according to the prior art formed by EP-B 1-2242627 . A mould container 1, the side walls 2 of which bound mould cavity 6, is shown in side view. Mould cavity 6 is bounded on the underside by a bottom 16 received displaceably in mould container 1. Displaceable bottom 16 forms part of an ejector 14.
Each mould container 1 also forms a chain part 8 of a chain conveyor, also referred to as mould conveyor. Chain parts 8 have link parts 10 and are further provided with running wheels 12 which can guide mould container 1 over a guide (not shown) of a mould container press (not shown either). Deep recesses 36 (visible in figure 2, which shows a first preferred embodiment of an ejector 14 according to the invention) result at the position of link parts 10. These deep recesses 36 impede the arranging of a spring washer 26 as final element.
As already described in the preamble, the ejector 14 shown in figure 1 is not suitable to be arranged at the position of a deep recess 36 (as shown in figure 2), because there is not enough space to slide the intermediate member (spring washer 26) between mould container 1 and spring 28. For positions at such recesses 36 it is not possible to apply a preassembled ejector 14 as according to figure 1 and known from EP-B 1-2242627 , but an ejector 14 has to be assembled in situ, as was usual prior thereto. This is the case for 20% or more of the ejectors 14 of a mould conveyor.
For the prior art embodiment shown in figure 1 this means that a bottom 16 with ejector shaft 18 is placed from mould cavity 6 through an opening 4 in mould container 1, after which a spring washer 26, a spring 28, a lock nut 24 and a cap nut 20 are successively arranged from the other side. In practice this labour-intensive method, which moreover introduces a possible adjusting inaccuracy due to the adjustment of cap nut 20, has to be applied for a large number of positions.
The edge 22 of cap nut 20 forms a stop for an outer end 32 of spring 28, so that spring 28 is tensioned between edge 22 and spring washer 26.

Description of the invention

Device 1 according to the invention proposes an improved device which can be applied at all positions, including the 20% or more positions where a deep recess 36 as shown in figure 2 is present.
For the embodiments of the invention shown in figures 2-12 similar measures are designated with the same reference numerals as used in the description of the prior art in figure 1, and a repetition of a description of the corresponding measures is largely omitted.
The perspective views of figures 1 and 2 show a mould container 1 with mould cavities 6. Although the figures show six mould cavities 6, such a mould container 1 can for instance comprise no less than thirty or more mould cavities 6. At least one ejector 40 is provided per mould cavity 6. This ejector 40 comprises a bottom 42 of the mould cavity 6 which is movable in the mould cavity for the purpose of ejecting a green brick formed in mould cavity 6, and an ejector shaft 44 with a support 50 extending from the bottom 42 of mould cavity 6. In the shown preferred embodiment support 50 is provided at a free outer end 48 of ejector shaft 44, where it can be easily reached. In a mounted situation of ejector 40 ejector shaft 44 extends through a bottom 3 of mould container 1. A spring 66 is provided which is tensioned between support 50 of ejector shaft 44 and bottom 3 of mould container 1. An inner diameter of spring 66 has a larger dimension than support 50, whereby spring 66 can be arranged over support 50 and to a position round ejector shaft 44. Further provided is an adapter 74 which is arranged between support 50 and spring 66 and encloses spring 66 between support 50 and mould container 1. Adapter 74 prevents a spring 66 arranged over support 50 and round ejector shaft 44 from being able to move back off ejector shaft 44 over support 50.
Although in the first preferred embodiment shown in figures 2, 3 and 6-12 the spring 66 lies with a first outer end 68 thereof against an intermediate member 62, it is also possible for spring 66 to support against mould container 1 itself, as is allowed by the second preferred embodiment shown in figures 4 and 5. In the case of a large opening 4 an intermediate member 62 may be desired to form a stop for the outer end 68 of spring 66 directed toward mould container 1.
Support 50 is fixedly mounted on ejector shaft 44 in non-adjustable manner, whereby a well controllable dimensioning of ejector 40 is obtained. The dimensioning is moreover reproducible with a high degree of accuracy for the large number of ejectors 44 of a mould conveyor with a support 50 which is fixedly mounted in non-adjustable manner, so that all ejectors 44 obtain almost the same setting.
The adapter 74 has an outer diameter D_o which is equal to or greater than the inner diameter D_v of spring 66. In mounted situation an outer end 70 of spring 66 remote from mould container 1 lies against the adapter 74 arranged against support 50. More particularly, outer end 70 of spring 66 lies against a support abutment 86 of a first part 82 of the adapter 74 which is arranged round support 50 (figures 11 and 12).
Adapter 74 is provided with an axial passage 76 which is configured to receive ejector shaft 44. Because adapter 74 is further provided with a radial passage 78, the adapter can be slid round ejector shaft 44 in lateral direction (indicated with an arrow in figure 10). Prior thereto, spring 66 is compressed so that sufficient space is created between outer end 70 of spring 66 and support 50 for adapter 74 to be placeable therebetween. As soon as the bias is removed from spring 66, spring 66 will extend and tension itself between spring abutment 90 of adapter 74 and mould container 1.
Adapter 74 is provided with a first part 82 comprising an accommodation 84 which is configured to receive an outer flange 54 of support 50. The part of support 50 received in accommodation 84 is shielded from the surrounding area by accommodation 84. Accommodation 84 is arranged in the side of adapter 74 which faces away from mould container 1 in a mounted situation. The outer flange 54 of support 50 is situated at the outermost free end 48 of ejector shaft 44, and a head part of outer flange 54 forms a surface 58 of support 50 remote from mould container 1.
Accommodation 84 has a depth d_a which substantially corresponds to, and is preferably slightly shallower than, the thickness d_f of outer flange 54. In mounted situation adapter 74 hereby lies substantially flush with the surface of support 50. In practice a difference in thickness of 0.5 mm suffices to guarantee that support 50 is engaged instead of adapter 74. Adapter 74, which is easily replaceable and can for instance be manufactured from plastic, can thus push aside sand and other contaminants before they come into contact with support 50. This reduces wear of support 50.
As can be seen most clearly in figures 10 and 12, adapter 74 has a stepped form 80.
Accommodation 84 is bounded on an inner side by a support abutment 86 which is configured to lie against outer flange 54 of support 50, and an inner wall 88 which encloses an outer surface 56 of outer flange 54 of support 50 in radial direction. Adapter 74 fits over the outer periphery 52 of support 50.
Adapter 74 is further provided with a second part 92 comprising an upright edge 94 which extends from first part 82. Upright edge 94 comprises an outer wall 98 with a diameter D_i which has a smaller dimension than the inner diameter D_v of spring 66 (figures 10A, 10B). The outer end 70 of spring 66 directed toward support 50 can hereby lie against the spring abutment 90 of adapter 74 on the outer side all around upright edge 94. Upright edge 94 forms a radial abutment for spring 66, which ensures a desired positioning of spring 66 relative to ejector shaft 44. The inner wall 96 of upright edge 94 is directed toward ejector shaft 44.
The shown ejectors 40 further comprise a screw thread connection arranged between ejector shaft 44 and bottom 42, whereby one or more than one washer 60 can be arranged as desired between ejector shaft 44 and bottom 42 of mould cavity 6. Washers 60 are arranged close to the outer end 46 of ejector shaft 44 directed toward bottom 42. This is because at the other outer end 48 support 50 is fixedly mounted in non-adjustable manner on ejector shaft 44. An upper side 5 of mould container 1 wears during use, whereby it becomes irregular and trimming of clay arranged in mould cavities 6 for the purpose of smoothing the green bricks is impeded and results in excessive wear of the trimming belt (not shown). During a revision of a mould conveyor the mould containers 1 are ground down to a somewhat level form, whereby they are levelled off. In order to maintain the dimensioning of the green brick the spacers 7 are shortened by the same thickness. To compensate for this shortening, ejector shaft 44 also has to be shortened correspondingly, which is done according to the invention by removing and/or replacing one or more than one washer 60. Compensating the dimensioning using washers 60 is easier, faster, better controllable and more accurate than a compensation by tightening of a cap nut 20 to greater or lesser extent, as in the prior art shown in figure 1.
The method of assembling an ejector 40 according to the invention is shown with reference to figures 4-12. It is noted that figures 4 and 5 show two successive steps on the basis of a second preferred embodiment and that figures 6-12 show successive steps on the basis of the first preferred embodiment which also forms the subject-matter of figures 2 and 3. The assembly steps are identical for both embodiments, and differ only in the presence of an intermediate member 62 for the first preferred embodiment.
The method for arranging an ejector 44 in a mould cavity 6 of a mould container 1 comprises as first step of placing an ejector shaft 44 of the ejector through an opening 4 in a bottom 3 of mould container 1, wherein the ejector forms a bottom 42 of mould cavity 6. Figure 4 shows the starting situation, in which an assembled ejector shaft 44 and bottom 42, such as can be prepared in a workshop, are supplied. After being placed through opening 4 the situation shown in figure 5 results, wherein ejector 40 forms the bottom 42 of mould cavity 6.
It is noted that figures 5 and 6 show the same situation for respectively the second preferred embodiment (figure 5) and the first preferred embodiment (figure 6). The further description of the assembly continues with the first preferred embodiment, which is provided with an intermediate member 62. In addition to an axial passage for ejector shaft 44, this intermediate member 62 preferably also comprises a radial passage 64 for ejector shaft 44 (figure 7), so that intermediate member 62 can be slid round ejector shaft 44 in radial direction in simple manner.
The situation shown in figures 5 and 6 is followed by the step of arranging a spring 66 round ejector shaft 44. The inner diameter D_v of spring 66 has a larger dimension than support 50, whereby spring 66 can be arranged over support 50 and to a position round ejector shaft 44 (figures 8 and 9).
Figure 10A shows the steps of compressing spring 66 (designated with arrow A), wherein a space is formed between support 50 and spring 66, and of then arranging an adapter 74 between support 50 and spring 66 (designated with arrow B). Adapter 74 prevents a spring 66 arranged over support 50 and round ejector shaft 44 from being able to move back off ejector shaft 44 over support 50.
When spring 66 is released and it extends again, spring 66 will tension itself between mould container 1 and the adapter 74 arranged round support 50 (figures 11 and 12).
The method can optionally further comprise the step of arranging one or more than one washer 60 round the screw thread. During a revision of a mould container the ejectors 40 are removed from the mould conveyor and the following steps can be performed for compensating for a levelling off of the mould conveyor:

loosening a screw thread connection between ejector shaft 44 and bottom 42 prior to arranging of the one or more than one washer 60; and
tightening the screw thread connection between ejector shaft 44 and bottom 42 after arranging of the one or more than one washer 60.

Although they show preferred embodiments of the invention, the above described embodiments are intended solely for the purpose of illustrating the present invention and not to limit the scope of the invention in any way. When measures in the claims are followed by reference numerals, such reference numerals serve only to contribute toward understanding of the claims, but are in no way limitative of the scope of protection. The rights described are defined by the following claims, within the scope of which many modifications can be envisaged.

Claims

Device, comprising:
- a mould container (1) with at least one mould cavity (6);

- at least one ejector (40) per mould cavity, comprising:
- a bottom (42) of the mould cavity (6) which is movable in the mould cavity for the purpose of ejecting a green brick formed in the mould cavity;

- an ejector shaft (44) extending from the bottom (42) of the mould cavity through a bottom of the mould container (1) and having a support (50) extending radially outward from the ejector shaft (44);

- a spring (66) which is tensioned between the support (50) of the ejector shaft (44) and the bottom of the mould container (1);
characterized in that
- an inner diameter of the spring (66) has a larger dimension than the support (50); and

- an adapter (74) is provided which is arranged between the support (50) and the spring (66), wherein the adapter (74) is provided with a radial passage with which the adapter (74) can be arranged round the ejector shaft (44) in a lateral direction.
Device according to claim 1, wherein the support (50) is fixedly mounted on the ejector shaft (44) in non-adjustable manner.
Device according to claim 1 or 2, wherein the adapter (74) has an outer diameter which is equal to or greater than the inner diameter of the spring (66) and wherein an outer end of the spring (66) lies against the adapter (74) arranged against the support (50).
Device according to any of the foregoing claims, wherein the adapter (74) is provided with an axial passage (76) which is configured to receive the ejector shaft (44).
Device according to any of the foregoing claims, wherein the adapter (74) is provided with a first part (82) comprising an accommodation (84) which is configured to receive an outer flange (54) of the support (50).
Device according to claim 5, wherein the accommodation (84) has a depth (d_a) which substantially corresponds to, and is preferably slightly shallower than, the thickness (d_f) of the outer flange (54).
Device according to any of the foregoing claims, wherein the adapter (74) has a stepped form (80).
Device according to claims 5 and 7, wherein the accommodation (84) is bounded on an inner side by a support abutment (86) for the outer flange (54) of the support (50).
Device according to claim 7 or 8, wherein the adapter (74) is provided with a second part (92) comprising an upright edge (94) which extends from the first part (82).
Device according to claim 9, wherein the upright edge (94) comprises an outer wall (98) with a diameter (D_i) which has a smaller dimension than the inner diameter (D_v) of the spring (66).
Device according to any of the foregoing claims, wherein the ejector (40) comprises a screw thread connection arranged between the ejector shaft (44) and the bottom (42).
Method for arranging an ejector (40) in a mould cavity (6) of a mould container (1), comprising the steps of:
- placing an ejector shaft (44) of the ejector (40) through an opening (4) in a bottom (3) of the mould container (1), wherein the ejector (40) forms a bottom (42) of the mould cavity (6) and wherein the ejector shaft (44) comprises a support (50) extending radially outward from the ejector shaft (44);
characterized by the steps of:
- sliding a spring (66), which has an inner diameter with a larger dimension than the support (50), over the support (50) and to a position round the ejector shaft (44); and

- arranging an adapter (74), which is provided with a radial passage (78) with which the adapter (74) can be arranged round the ejector shaft (44) in a lateral direction, round the ejector shaft (44) and between the support (50) and the spring (66) in a lateral direction.
Method according to claim 12, comprising the step of compressing the spring (66) prior to arranging of the adapter (74) between the support (50) and the spring (66), wherein a space is formed between the support (50) and the spring (66).
Method according to claim 13, comprising the step of arranging one or more than one washer (60) between the ejector shaft (44) and the bottom (42) of the mould cavity (6); and
- preferably comprising the steps of:
- loosening a screw thread connection between the ejector shaft (44) and the bottom (42) prior to arranging of the one or more than one washer (60); and

- tightening the screw thread connection between the ejector shaft (44) and the bottom (42) after arranging of the one or more than one washer (60).
Method according to claim 14, comprising an ejector (40) according to a device of any of the claims 1-11.