EP3833629B1 - Device for the pressurized filling of containers - Google Patents

Description

The present invention relates to a device for pressure filling of containers. Such filling devices, primarily beverage filling machines for pressure-filling containers, predominantly rotary filling machines, contain a large number of filling stations with filling elements that have filling valves with sealing elements for pressure-tight contact of the filling element with a container mouth.

Such rotary filling machines are provided with a splinter guard, which often has a stationary clamping zone covering surrounding the rotor and/or radially and vertically extending separating plates rotating with the rotor in order to reduce the uncontrolled flying around of broken glass. Glass breakage can occur when filling containers made of glass, which have to be filled at a higher pressure than atmospheric pressure due to the filling material. These include carbonated beverages such as soft drinks or mineral water with CO ₂ components. The necessary filling pressure is usually around 0.5 bar above the saturation pressure of the CO ₂ . Thus, glass bottles to be filled are filled with 5.5 - 6.0 bar. For this purpose, the empty glass bottles are pressed onto the filling valve of the filling element of each filling station via a feed star wheel after they have entered and are pre-tensioned to the necessary saturation pressure of the beverage to be filled. The corresponding area is called the span area. Particularly in the case of reusable glass, which undergoes up to 30 circulations through the consumer for refilling, there is a great risk that damaged areas that were not recognized during tempering could lead to the bottle breaking.

When the bottle breaks, these pieces of glass flying around in an uncontrolled manner pose a significant risk in terms of product liability. Broken pieces of glass vary in size and shape. Their weight is also different. The applicant has determined from high-speed recordings that an impacting piece of cullet breaks up in a cascade after impact into recurring smaller pieces until the overall energy is reduced in such a way that a remaining piece only flies on in a deflected manner. Ultimately, there is even the danger that the constantly breaking small pieces of glass will reach the bottle necks in the filling area and then reach the customer with the filled product.

In order to reduce the kinetic energy of the flying glass splinters, a splinter protection with a stationary clamping zone panel and is in the prior art Proposed between the filling stations arranged separating plates having a support wall made of metal and at least one of the filling element facing absorption element made of plastic. In this plastic absorption element, the energy absorbed when it hits the cladding is reduced to such an extent that the subsequent fracture phenomenon described above is reduced. One problem with this splinter protection is that the glass splinters get stuck in the absorption element and the absorption element thereby increasingly loses its absorbent properties. In addition, the absorption element has increasingly sharp and pointed edges due to the stuck glass splinters, which lead to a risk of injury during handling. They can also only be cleaned inadequately. The absorption elements or the complete separating plates therefore have to be replaced frequently.

The filling machines are currently being equipped with clamping zone covers made of sheet metal in the stationary outer area and with separating plates attached to the rotor between the filling stations in the rotating carousel area. The disadvantage here is that the rigid shape basically limits flying glass pieces but cannot influence the strong scattering of the subsequent fragments.

The WO 2015/091050 A1 shows a device according to the preamble of claim 1, in which absorbing elements are provided freely suspended in order to absorb the kinetic energy of splinters.

It is the object of the invention to provide a device which enables safer pressure filling of containers and reduces the risk of contamination of the product-carrying components of the machine.

The object is solved by a device according to claim 1. Advantageous developments of the invention are the subject matter of the dependent claims.

The device according to the invention for pressure-filling containers has a large number of filling stations with filling elements which have sealing elements for pressure-tight contact of the filling element with a container mouth. The device contains a splinter guard facing the filling station at least in the clamping area, which has at least one support wall and at least one absorption element attached to the support wall and facing the filling element.

According to the invention, the absorption element contains at least one resiliently deflectable section for reducing the kinetic energy of the glass splinters flying around.

Spring-elastically deflectable is a section whose deflection corresponds to a linear elastic behavior according to Hooke's law, and in which the deflection path is at least 0.2 mm, preferably at least 0.5 mm. This ensures that a glass splinter that jumps off when a bottle bursts transfers a lot of its kinetic energy to the deflectable section when it hits the deflectable section, which drastically reduces the risk of further splintering or bouncing off and further flying around in the filling area.

In principle, the sections could be formed by rigid metal sheets, which are prestressed against the supporting wall, e.g. by means of compression springs, for example coil springs, so that when a splinter hits, they are briefly deflected in the direction of the outer wall and thereby reduce the kinetic energy of the splinter.

According to the invention, the elastic sections are held on or formed by a wall structure which is arranged parallel to the supporting wall and is preferably connected to it, e.g. The wall structure can be screwed to the supporting wall, for example. The effect of this is that the supporting wall can be designed very simply, for example in the form of metal sheets, while the plurality of elastic sections is supported by or formed by the wall structure. There is thus a clear separation of tasks between the supporting wall, which should preferably be smooth and as easy to clean as possible, and the wall structure, which should be held on the supporting wall as easily as possible in an exchangeable manner, e.g. to facilitate cleaning, inspection or replacement. The wall structure with the resilient sections, which thus forms the absorption element, can thus be easily unscrewed from the supporting wall and attached to it again for cleaning. For this purpose, in particular, a detachable attachment of the wall structure to the supporting wall is provided, for example with a screw connection.

The wall structure consists of a particularly resilient material and is formed in one piece with the sections, the sections being formed from the wall structure by a cutting or stamping process. For example, a Spring steel sheet are provided with slot and / or U-shaped punches or cuts, resulting in the spring steel sheet, the spring-elastic sections that are the elastic behavior of the spring steel against the wall structure deflected as a whole. Such a wall structure forming the absorption element is therefore easy to produce and is also less susceptible to contamination. By subdividing it into many smaller, easily deflectable sections, such a wall structure is able to efficiently reduce the kinetic energy of an impacting glass splinter. The punchings and/or cuts are distributed as evenly as possible over the wall structure in order to form deflectable sections of the same size.

In an advantageous development of the invention, the sections are made of metal, in particular spring steel. In this way, no additional spring-elastic elements such as compression springs, helical springs or spiral springs are required, but the spring steel sections themselves form the elastically restorable elements that absorb the kinetic energy of the splinters flying around.

Preferably, the sections are rectangular with a longer and a shorter side, being fastened in particular on their shorter side to the supporting wall or to a wall structure provided parallel to the supporting wall, which serves to accommodate the resiliently deflectable sections.

The sections are preferably designed as elongated lamellae, which preferably extend in the horizontal or vertical direction. These slats are preferably connected to the wall structure or supporting wall at their narrow end side and thus have a long range in which they are able to intercept flying splinters and, according to their deflection, reduce their kinetic energy.

The splinter guard preferably comprises a stationary clamping zone cover and/or separating plates arranged between the filling stations. In this way, the filling machine is optionally shielded from the outside and/or between the filling stations.

Preferably, the absorption element is arranged at the partition plates on both sides of the supporting wall, so that it can shield the splinters from the two adjacent filling stations at the same time.

In an advantageous embodiment of the invention, the device is designed as a rotary filling machine with a rotor axis and many filling stations arranged around the rotor axis, with at least some of the resiliently deflectable sections being designed as segmenting plates pointing towards the rotor axis, which Clamping area of the rotor surrounding clamping zone covering are attached, so that a splinter protection is achieved in a simple manner, which also effectively prevents movement of the fragments in the circumferential direction.

The segmenting plates, but also the outer wall segments, can preferably consist of a single layer of spring steel. With these, the support structure is then identical to the spring-elastic wall structure. These single-layer segmentation sheets (outer wall segments) thus integrate both load-bearing and impact-absorbing properties.

The wall structure is preferably held detachably on the supporting wall, for example by screw connections or snap connections, so that it can be replaced, inspected or cleaned without great effort.

Preferably, the supporting wall consists of at least one metal sheet (outer wall) that extends in particular vertically and which, for example in a rotary filling machine, concentrically surrounds the rotor and thus shields the filling elements arranged in the filling stations from the outside. The metal sheet or several metal sheets screwed together to form a supporting wall form an outer wall and are preferably structured smoothly and are therefore easy to close from the outside clean. On the other hand, they carry connecting elements such as holes for accommodating screws or connecting elements of a snap connection, in order in this way to be able to attach the wall structure or the spring-elastic deflectable sections directly to it. They are also used to fasten radially extending segmenting plates. If the resiliently deflectable sections are arranged on a wall structure, the wall structure and the supporting wall preferably form a double-wall construction, with the wall structure being held at a distance from the supporting wall so that the resiliently elastic sections can deflect when a splinter strikes, without closing the supporting wall touch. The distance should therefore be greater than the maximum expected deflection of the spring-elastic sections when hit by a large splinter.

Preferably, the splinter protection surrounds each filling station as completely as possible, which can be realized by providing a stationary clamping protection paneling in the clamping area of the filling machine and by providing separating plates between the filling stations. In this way, if a bottle bursts, glass splinters cannot reach neighboring filling stations or the work area around the filling machine.

The device is designed in particular as a rotary filling machine in which the filling stations are arranged equidistantly on an outer ring area of the rotor of the rotary filling machine. Such a rotary filling machine allows high filling performance. In addition, the splinter protection can be easily implemented in the form of a stationary clamping zone cover in the clamping area (segment) of the filling machine or in the form of separating plates extending radially between the filling stations. The filling stations are thus completely surrounded by the splinter protection in the clamping area. If a bottle breaks in a filling station, this does not affect the neighboring filling stations or the work area surrounding the filling machine.

For better understanding, it should also be stated that the splinter guard on a rotary filling machine is only stationary in that angular range of the rotary filling machine in which the bottles are pretensioned and pressure filled (tensioning range), i.e. in which a comparatively high pressure is exerted on the glass bottles abuts the glass bottles due to material defects may burst when pressure is applied. The support wall can either itself be attached to a fixed structure such as a floor or a frame of the rotary filling machine or to brackets which in turn are connected to the frame of the filling machine or to a mounting structure of the filling machine.

In an advantageous embodiment, the wall structure consists of flexibly arranged metal sheets, primarily made of spring steel 1.4310, primarily made of stainless material, in which the spring-elastic sections are integrated in such a way that they react flexibly when glass fragments hit, in order to absorb the impact energy and thus the further multiple Prevent the glass splinters from shattering. The high, small individual splinters that would otherwise occur are drastically reduced and, as a result, operational and product safety increases. The sections can be formed by the wall structure itself, in particular if the wall structure is divided into smaller, more easily movable sections by punching or cutting.

This wall structure can be provided both on the stationary clamping zone cladding and on the separating plates arranged between the filling stations.

In the case of the separating plates, a partition arranged at right angles to the filling valve is often welded to the vertical part of the separating plate at the bottom. This can continue to be practiced as spring steel sheets in quality 1.4310 can be easily welded and deformed.

The elements used for the splinter protection can be reduced to a few standard parts, the installation of which can be individually adapted. The material 1.4310, X10CrNi188 has proven to be advantageous for the wall structure and the sections of the splinter protection.

The stability of the separating plates has a decisive influence on the function of the filling machine, especially in the area of the inflowing and outflowing bottle relative to the filler carousel, ie the outer area of the rotor of the rotary filling machine in which the filling stations are arranged.

Parameters for the production of the filling machine are e.g. the pitch of the machine (also called PI pitch), bottle diameter, projection of the separating plates over the pitch circle of the filling machine in the radius, separating plate thickness, pitch circle diameter of the filler carousel, diameter of the infeed and ejector wheels are in relation to each other and must be matched to the contour of the bottle to be processed. From this it follows that a misalignment of the otherwise vertically arranged separating plates impedes the moving in and out of the bottles or leads to their breakage. The separating plates should therefore preferably be aligned vertically and radially and preferably be spaced equidistantly from the filling stations. In the proposed version, the separating plates can be made thinner than is currently the case, since the spring effect of the sections supports restoring movements after a glass breakage impact.

In the area of the separating plates, the contour cuts are set in such a way that the bottle is primarily bent up against the incoming bottle. The incoming bottle is prevented from hitting the bent out blunt edge of the bending contour. The combination of flexible and rigid elements is also part of the claim. The connection and installation can also be carried out differently.

The construction of the stationary clamping zone covering consists primarily of two main components:
The first component is formed by supporting plates (supporting walls) extending in the circumferential direction of the filling machine in the form of an outer wall with absorption elements facing the filling machine in the form of wall structures with integrated spring-elastic sections.

In addition, the clamping zone cladding has, as a second component, segmenting plates which extend radially inwards, but which do not, however, reach into the area of the rotor. These mutually spaced segmenting plates, which are preferably attached to the supporting plate of the outer wall, are intended to prevent splinters from moving in the circumferential direction of the rotor of the filling machine. These segmenting plates are preferably arranged at a distance of 15 cm to 50 cm from one another and preferably consist of a supporting plate with segments arranged on both sides resilient wall structures having integrally formed resilient sections. The side edge of the platens facing away from the filling machine preferably abuts against the support plate of the outer wall. Due to its resilient wall structure, the connection to the sealed outer wall (sheet metal cladding) that seals off the outside allows elastic deformation when glass fragments hit it. The dimensions of the support plate and wall structure are to be selected in such a way that jamming of glass fragments during reshaping is largely avoided, but the deflection of the sections is still guaranteed.

If they nevertheless occur, subsequent impacts from glass fragments lead to a self-healing effect with a return to the starting position. If necessary, the stationary attached outer wall or outer wall segments can be removed and mechanically inspected or cleaned or replaced.

The invention has been described mainly in connection with a rotary filling machine, but it is also applicable to a linear filling machine, i.e. a filling machine with a linear conveying and filling path.

For cleaning purposes, a cleaning arrangement with nozzles can be provided in the area of the splinter protection, which sprays the components of the splinter protection with a high-pressure water jet and thus cleans them of stuck glass splinters. This cleaning arrangement is preferably directed with its nozzles onto the spring-elastic sections or the at least one wall structure of the splinter guard.

The following expressions are used synonymously: support wall - support plate; Outer wall - supporting wall of the stationary anti-stress cladding; Structural wall - smooth metal sheets with attachments for resilient wall structures or sections and/or segmentation sheets; Segmentation plates - radially extending, spaced apart parts of the stationary anti-stress cladding, preferably with elastic wall structures on both sides; Wall structure—spring-elastic sheet metal with cuts and/or stampings for subdividing into separately deflectable spring-elastic sections;

It should be clear to a person skilled in the art that the above embodiments of the invention can be combined with one another in any way without departing from the scope of protection defined by the appended claims.

Fig. 1

eine schematische Aufsicht auf eine Rundfüllmaschine mit einer Anordnung des Splitterschutzes im Vorspann- und Druckbelastungsbereich der Flaschen,

Fig. 2

ein Segment zur Bildung des Splitterschutzes aus Fig. 1,

Fig. 3

ein Detail des Segments aus Fig. 2,

Fig. 4

ein planes Segment zur Bildung eines Splitterschutzes bei einer linearen Abfüllstrecke,

Fig. 5

ein Detail aus Fig. 4 in perspektivischer Ansicht,

Fig. 6

eine Aufsicht auf das planare Segment der Fig. 4 mit zwei Halterungen für den Splitterschutz, und

Fig. 7

eine Trennblechstruktur einer Rundfüllmaschine zur Abtrennung der Füllstationen voneinander.

The invention is described below by way of example using the schematic exemplary embodiment. In this show:

1

a schematic plan view of a rotary filling machine with an arrangement of the splinter protection in the preload and pressure load area of the bottles,

2

a segment to form the splinter protection 1 ,

3

a detail of the segment 2 ,

4

a flat segment to form a splinter protection in a linear filling line,

figure 5

a detail out 4 in perspective view,

6

a planar view of the segment of the 4 with two brackets for the splinter guard, and

Figure 7

a partition plate structure of a rotary filling machine for separating the filling stations from each other.

1 shows an embodiment of the filling device according to the invention in the form of a rotary filling machine 10 which has a rotor 12 which rotates about a rotor axis X and has a plurality of filling stations 14 which are arranged at equidistant intervals over the circumference. Each filling station 14 contains a filling element 16 which can be brought into pressure-tight connection with a bottle to be filled or with another pressure-capable container, in particular a glass bottle. The rotor 12 rotates in direction A. The filling machine 10 also includes an infeed starwheel 18 and an outfeed starwheel 20, with which containers are transferred to the filling stations 14 and removed from them again. The angular range in which the containers are pretensioned and filled under pressure, i.e. the clamping range B. The rotary filling machine 10 contains a splinter guard 19 comprising a stationary clamping protection cladding 22 surrounding the rotor 12 in the clamping range B, which is intended to prevent splinters from falling under the container when it bursts Pressure fly into the environment. The instep protection paneling 22 is preferably made up of individual outer wall segments 24a-d, which are connected to one another at their side edges 26 and thus cover the entire angular range B on the outside. The Span guard 22 further includes spaced stationary segmentation baffles 40a-40e extending radially from outer wall segments 24a-d toward the rotor and serving to prevent circumferential splinter discharge. The segmenting plates 40a to 40e are preferably attached to the outer wall segments 24a-d. The splinter guard 19 also contains partitions 21 which are arranged between the filling stations and rotate with the rotor 12. They separate the filling stations 14 from one another and ensure that splinters do not get into the area of neighboring filling stations 14 .

The outer wall segments 24a-d forming the protective covering 22 are shown in FIGS Figures 2 and 3 rendered in more detail. Each outer wall segment 24a-d includes a plain sheet metal support wall 30 which is secured to the frame of the filling machine 10 by a bracket 32. As shown in FIG. Each supporting wall 30 has fastening points 34 for the screw fastening of at least one wall structure 36, each of which is formed from at least one spring plate, in which elongated 39 and U-shaped 37 cuts are cut or stamped, so that smaller sections 38, 41 are formed which are connected to the wall structure 36, preferably at a narrow end 40. In this way, the wall structure 36 is divided into a large number of separately deflectable, resilient sections 38, 41 which, when a splinter strikes, lead to a deflection of the corresponding resilient section 38, 41 and thus to a reduction in its kinetic energy. This ensures that the work area is effectively secured on the one hand and on the other hand that flying parts are prevented from having a negative impact on the filling process on neighboring containers. The advantage over known plastic absorption elements is that the spring-elastic sections are elastically deformable and move back completely into their original position after a splinter hits them. The service life of the wall structure containing the resilient sections is thus considerably longer than with known polymeric absorption elements. For cleaning or replacement, the connecting elements 34 such as screws or snap fasteners can be quickly released and thus allow cleaning or replacement of the corresponding wall structures including the associated sections 38 . Each outer wall segment 24a-d further includes segmenting plates 40a-e, which extend radially from the outer wall segments 24a-d in the direction of extend the rotor axis X and reach up to the rotor 12. These segmenting plates 40a-e are also made of spring steel and contain deflectable, resilient sections 38, 41, which are also formed by linear and U-shaped cuts 39, 37 in the segmenting plates 40a-e. The segmenting plates 40 contain fastening eyelets 42 with which they can be fixed to the outer wall segments 30 by means of screw or snap connections 34 . Since the segmenting plates are made entirely of spring steel, they are elastically deformable per se and thus form an elastically deflectable section without further subdivision. If the segmenting plate 40a-3 has, for example, a plurality of horizontally running incisions, it is easier for individual sections formed in this way to be deflected when a splinter strikes. Thus, with such a segmenting plate, the formation of individual resiliently deflectable sections can be realized by providing incisions in this way, in particular from the free end. In the case of the segmenting plates, the support wall is designed to be integrated with the wall structure.

4 shows a splinter protection segment analogous to 2 , which is not curved, but flat and thus serves to shield a linear filling section. To the 2 identical elements are provided with identical reference symbols. The side edges 26 of the planar supporting wall segment 52 are flanged at 90 degrees and have recesses 56, so that planar splinter protection segments 50 can be connected to one another at their side edges 26, for example via screw connections. In this way, linear splinter protection routes of any length can be formed. The planar flak segment 50 further includes a 90 degree crimped bottom edge 58 that provides the flak segment 50 with greater stability.

6 shows a mounted flat splinter protection segment 4 , which is attached to the frame of a linear filling machine by two brackets 60a, 60b.

Finally shows 7 an arrangement of radially extending separating plates 21, which are attached indirectly by means of a support structure 60 and directly by means of fastening elements 62 to the rotor 12 of the filling machine 10 between the filling stations 14. Each separating plate 21 consists of spring steel and is U-shaped solely by means of it Sections 37 are divided into horizontally extending elongate sections 38 and 41 which are separately capable of elastically deforming upon impact with a splinter of glass to remove kinetic energy from the splinter. The filling stations are thus also separated from one another, so that no splinters can get into neighboring filling stations 14 if a bottle breaks.

The invention is not limited to the embodiments described above, but can be varied at will within the scope of the attached patent claims.

Reference list:

10

(Round) filling machine

12

Filling machine rotor

14

filling station

16

filling element (filling valve)

18

inlet star

19

shatter protection

20

outlet star

21

Splinter shield dividers

22

Instep guard panel

24a-d

Arc-shaped outer wall segments of the instep protection paneling

26

Side edges of the outer wall segments

30

Supporting wall of the outer wall segment

32

stationary mounting of the outer wall segment on the filling machine or on the building

34

Attachment points (screw attachment, snap attachment)

36

Wall structure of the outer wall segment

37

U-shaped cut in the wall structure

38

elongated first section

39

linear cut in the wall structure

40

Segmenting plates, in particular of spring steel

41

elongated second section

42

Fastening eyes of the segmenting plates

50

planar outer wall segment

52

Supporting wall of the planar outer wall segment

56

Recesses in the side edges

58

Lower edge of the outer wall segment

60

Support structure for the separating plates on the rotor

62

Fastening elements for direct attachment of the separator plates to the rotor

Claims (14)

1. Device (10) for the pressure-filling of containers, with a plurality of filling stations (14) with filling elements (16), which comprise sealing elements for a pressure-tight contact of the filling element with a container mouth, said device (10) comprising, at least in the tension region (β), a splinter protection element (19) facing towards the filling station (14), which in turn comprises at least one absorption element (36a-d) facing towards the filling station (14), wherein the absorption element (36a-d, 21, 40a-e) comprises sections (38, 41) which can be deflected in a spring-elastic manner, characterised in that
   the absorption element (36a-d, 21, 40a-e) comprises a wall structure (36a-d) or is formed by a wall structure (36a-d), at which the sections (38, 41) which can be deflected in a spring-elastic manner are formed as one piece (37, 39), and that the sections (38, 41) are formed in the wall structure by a cutting or stamping process.
2. Device (10) according to claim 1, characterised in that the absorption element (36a-d) is secured to at least one supporting wall (30, 52) or are formed as integrated into it.
3. Device (10) according to claim 1 or 2, characterised in that the splinter protection element (19) comprises a stationary tension region cladding (22) and/or separating plates (21) arranged between the filling stations (14), at which the sections (38, 41) are held or formed.
4. Device (10) according to any one of the preceding claims, characterised in that the sections (38, 41) consist of metal, in particular of spring steel.
5. Device (10) according to any one of the preceding claims, characterised in that the absorption element (36a-d, 21, 40a-e) comprises stationary segmenting plates (40a-e) running transverse to the wall structure (36a-d), in particular made of spring steel, in which the sections (38, 41) are formed.
6. Device according to any one of the preceding claims, characterised in that the wall structure (36a-d) is formed at a stationary tension region cladding (22).
7. Device (10) according to any one of the preceding claims, characterised in that the absorption element (36a-d, 21, 40a-e) comprises separating plates (21) formed between the filling stations, made of a spring-elastic metal, in which the sections (38, 41) are formed by a cutting or stamping process.
8. Device (10) according to any one of the preceding claims, characterised in that the wall structure (36a-d) consists of a spring-elastic metal.
9. Device (10) according to any one of the preceding claims, characterised in that the wall structure (36a-d) is held in a detachable manner at the supporting wall (30, 52), in particular by a screw connection or by a snap closure fitting.
10. Device (10) according to claim 9, characterised in that the supporting wall (30, 52) consists of at least one metal plate, in particular with smooth walls.
11. Device (10) according to any one of the preceding claims, characterised in that the wall structure (36a-d) and the supporting wall (30, 52) form a double-wall construction, wherein the distance interval between the supporting wall and the wall structure (36a-d) is at least as great as the anticipated maximum deflection of the sections (38, 41) in the event of the impact of a large container splinter.
12. Device (10) according to any one of the preceding claims, characterised in that it is configured as a circular filling machine, and that the splinter protection element (21) comprises a stationary tension region cladding (21) surrounding the tension region (β) of the rotor (12) of the circular filling machine (10), as well as separating plates (21) secured to the rotor (12) between the filling stations (14), which are oriented vertically and radially.
13. Device (10) according to any one of the preceding claims, characterised in that the tension region cladding (21) is formed by several wall structures (36a-d), running parallel to the supporting structure (30, 52) as well as the outer wall segments (24a-d) with a supporting structure (30, 52), which are connected to one another at their side edges (26).
14. Device (10) according to claim 13, characterised in that the side edges (26) are curved through 90 degrees towards the filling station (14), and preferably comprise cut-out openings (56) for mutual securing.

Images