Patent Application
20200072262
The present invention is directed to an insert, in particular to an insert to be used in panels with core structures made from a cellular solid, such as honeycomb panels. The invention is also directed to an insert system comprising such an insert and a panel. The present invention is further directed to a method to produce such an insert system. The present invention is further directed to a machine system to produce an insert system and to a working head for such a machine system. The present invention is further directed to a magazine to store inserts and to be used for such a machine system. The present invention is further directed to an adhesive dispenser to be used for such a machine system.
Several types of insert systems suited for being used in panels with core structures made from cellular solids are known.
U.S. Pat. No. 3,485,282 was published on 23 Dec. 1969 on behalf of Hughes Aircraft Company and shows an expandable insert for solid and cellular structures, like honeycomb constructions. The insert disclosed comprises a specific amount of expandable bonding agent that is specifically or precisely measured. In one embodiment disclosed in U.S. Pat. No. 3,485,282, the insert comprises a cylindrical casing which has a plurality of apertures spaced about its periphery. An attachment as a nut is secured centrally within the casing. Within the casing, an expandable bonding agent is arranged. In order to install the insert in a cellular structure, the insert is placed within a preformed hole in the cellular structure. After that, a catalyzing agent, namely heat, is applied to the insert which causes the expandable bonding agent to expand and through the apertures in the casing and hence extrude into the peri-insert cells opened by the hole in the cellular structure. According to the publication, the bonding means then expands until it fills completely all ruptured cells. A disadvantage of such an insert is that heat or another catalyst has to be induced which may affect the surrounding cellular structure. As well, in order to completely fill all ruptured cells a certain minimum volume of expandable bonding agent is needed which will stay within the case and hence adds to the total weight of the insert, although it does not contribute to fixation of the insert in the surrounding cellular structure.
WO 2016/102305 A1 was published on 30 Jun. 2016 on behalf of Alema Automation and discloses a feeder mechanism for feeding mechanical fasteners, such as rivets, screws, bolts and similar. The application shows a feeder mechanism that has a transport means for transporting the mechanical fasteners preferably by pressurized air and a stopping and aligning unit with a stopping plate to decelerate transported fasteners arranged downstream of the transport means. According to the application the transport means allows feeding of fasteners at high speed and frequencies, while the stopping and aligning unit reduces damaging of the mechanical fasteners by decelerating them with the stopping plate.
WO 2008/124353 A1 was published on 16 Oct. 2008 on behalf of The Boeing Company and discloses an apparatus for installing fasteners in a workpiece and is mounted for computer controlled movement over the workpiece. According to the application the apparatus has all entities on-board that are needed to operate autonomously without external connections, including tools, fasteners, drives and controls. As well it may include on-board power supply for powering the tools, drives and controls. In addition it comprises a supply of fasteners by means of an on-board replaceable cassette. According to the application, an on-board fastener transferring device transfers individual fasteners from the cassette to the tools. Therefore the apparatus comprises a base on which a supply of fasteners is mounted as well as means for mounting the base for movement over the surface of the workpiece. As well, at least one tool is mounted on the base for installing the fasteners in the workpiece along an installation path. In addition, controls are mounted on the base for controlling the operation of the tool. The type of apparatus disclosed in WO 2008/124353 A1 is intended to be used as a robot that is crawling essentially autonomously along the fuselage of aircraft in order to join the outer skin with the fuselage frames. The various components necessary to fulfill this task make the apparatus relatively heavy. Consequently such an apparatus can only work autonomously on structures that have a relatively high structural competence or in combination with an auxiliary device that comprises a relatively high stiffness.
WO14060027 A1, WO14146739 A1, WO14146740 A1 have been published, which all disclose inserts for being mounted in panels using adhesives.
Most inserts foreseen to be mounted into composite panels used in aviation have the drawback that automated mounting is hardly possible due to several reasons.
A first reason is that composite panels used in aviation typically comprise materials that show very special mechanical behavior and/or require very specific processing. This in particular holds true for sandwich-type panels that comprise core materials made from cellular solids, such as an open-cell or closed-cell solids like e.g. foam materials or honeycomb materials. As such, a panel may e.g. comprise a core made from a plastic material or a fiber reinforced plastic material. In panels intended to be used in aviation (e.g. for aircraft cabin flooring and interiors), materials comprising aramid and/or para-aramid and/or meta-aramid fibers are widespread. As well, also the cover sheets of composite panels which may be made from the same materials (in particular from aramid and/or para-aramid and/or meta-aramid) like the core structures or from a different type of material may anticipate automated mounting of inserts. Furthermore, the composite panels as used in aviation in many cases comprise special types of coatings, including different types of varnish, glass, wood, bamboo as well as stone applied as veneer. When inserting inserts in panels made from these materials, the panels' mechanical response to the insertion process can typically only be controlled (respectively forecasted) to a very limited extent. A major reason for this is the type of material the panels are made from, which typically show a nonlinear and sometimes even discontinuous mechanical response during mounting of an insert.
Another reason that anticipates automated mounting of inserts is that most panels used in aviation are typically thinner than most panels used e.g. in satellites. For inserts to be mounted in e.g. sandwich panels this increases the influence of the cover sheets on insert stability. As well, the spatial dimensions of the inserts applied in aviation are in many cases smaller than those of the inserts applied to space structures. Consequently, in many cases the macrostructure of the sandwich panels' core structures is similar or at least in the same size range like the insert. This makes the mechanical response of the panel to insertion of the insert highly dependent on the insert position. Consequently, accurate positioning of inserts in many cases becomes difficult which antagonizes automated mounting of inserts.
Conventionally, inserts are set in a pre-produced opening in the panel and subsequently an adhesive agent is injected in the peri-insert region space in order to fill any free volume and hence augment the structural stability of the insert-panel structure. However, such injection of adhesive agent usually results in the adhesive agent contacting both cover sheets of a sandwich panel. This may affect the optical appearance of the panel in particular in two ways. First, adherence of the adhesive agent to a cover sheet may induce a change in color of the cover sheet, respectively of a coating (e.g. varnish) of a cover sheet. Second, injection of the adhesive agent may cause the cover sheet to bulge or alternatively the adhesive agent may shrink during hardening and cause an indentation/dent in at least one of the cover sheets. In particular on high quality/gloss surface finishes such bulges or indentions are usually readily noticed by an observer due to the distortion of reflected light, making extensive further treatment necessary. As well, conventional injection of adhesive agent typically requires relatively large amounts of adhesive agent which, particularly in honeycomb panels, may flow to regions where it does not efficiently contribute to insert stability/anchorage.
Another reason impeding automated mounting of inserts in the above-mentioned types of panels is that due to the specific mechanical behavior of these panels conventional inserts do not provide sufficient initial insert stability, making it necessary to use auxiliary means in order to keep them in place during curing of an adhesive agent. This typically impedes mounting of multiple inserts and hence slows down production of panels comprising multiple inserts.
An insert according to the present invention typically comprises a base and an outer skirt extending from the base, thereby forming a chamber. The outer skirt is provided with a first inner skirt surface and a first outer skirt surface. According to the present invention, the insert comprises at least one fixation means arranged at the first outer skirt surface and configured to interact (respectively interfere in a defined manner) with a panel when inserted in an opening of the panel in order to increase initial insert stability. Thus, the fixation means interfering with the panel and the outer skirt interfering with adhesive agent in the peri-insert region of a panel provide sufficient initial insert stability to maintain insert position and alignment during curing/hardening of the adhesive agent and finally obtain long term insert stability.
For some applications, at least a part of the skirt may have a rotationally symmetrical shape. Good results may be obtained if at least a part of the skirt has a cylindrical or a conical shape.
Good results can be obtained if the fixation means is arranged at the region of the outer skirt which is adjacent to the base. Thus, the fixation means may interfere with a first cover sheet of a panel which allows to obtain very high initial insert stability. Such an embodiment of an insert according to the invention is particularly advantageous for being used in panel that comprise relatively core structures with relatively large cells.
According to a variation of the invention, the fixation means may comprise at least one thickening which at least partially protrudes from the first outer skirt surface. Hence an interference-fit may be obtained. For certain types of panels multiple thickenings may be are arranged circumferentially distributed around the outer skirt surface of the insert. An insert that offers very good initial- and long-term stability in panels having relatively sensitive cover sheets may be obtained if the fixation means comprises multiple thickenings that protrude from the first outer skirt surface and are arranged circumferentially distributed around the first outer skirt surface whereby the protrusions are arranged and formed such that they do not induce any critical stress the peri-insert region of the cover sheet, in particular do not produce a critical notch effect. The shape and material of the thickening, respectively the thickenings, may be adapted to the thickness and the material of the cover sheet of a plane the insert is to be inserted in.
Alternatively or in addition, the fixation means may comprise at least one recess, which may extend in circumferential direction around the first outer skirt surface.
For certain types of panels the fixation means may comprise a knurl pattern and/or a corrugation, which may e.g. be made by an embossing process or by molding.
For certain types of panels, in particular for panels that are mechanically particularly sensitive, the fixation means may be at least partially made from a polymer material. In order to obtain particularly high initial insert stability, the polymer material may comprise an adhesive agent. Alternatively or in addition, the polymer material may be a silicone. The adhesive agent may be configured to obtain an at least temporal adhesive bonding between the insert and the panel to be mounted in. To facilitate insertion of the insert a non-permanent adhesive agent may be applied. As well, the adhesive agent may be thermoactive. Good results may be obtained if the polymer material is arranged as a coating layer on the first outer skirt surface.
For certain applications, the fixation means may comprise a coating layer that has a friction coefficient which is higher than the friction coefficient of the non-coated part of the first outer skirt surface. Hence, for certain types of panels insertion depth of an insert can be better controlled.
Good results may be obtained if at least part of the fixation means is integrally made with the outer skirt. Alternatively, or in addition at least part of the fixation means may be made from a different material than the outer skirt. The fixation means may be produced by means of an injection molding process.
For some applications, at least one first groove may be arranged at the first outer skirt surface closer to the free end of the outer skirt than to the base end of the outer skirt which is arranged at the base. Hence, initial as well as long-term insert stability may be significantly be improved.
According to a variation of the invention, the at least one outer skirt comprises at least one slot arranged at the free end of the outer skirt and extending from the inner skirt surface to the outer skirt surface. Good results may be obtained if multiple slots are arranged circumferentially distributed around the outer skirt surface. Thus, an insert may be obtained which can be produced at low costs as well as it offers good resistance against torsional load and allows easy mounting. Alternatively or in addition, the outer skirt may comprise at least one opening arranged a distance apart from the free end of the outer skirt and extending from the inner skirt surface to the outer skirt surface to increase pull-out strength when combined with adhesive agent.
For some applications, the insert may comprise an inner skirt that extends from the base and is arranged in the chamber and spaced apart a distance from the outer skirt. According to an embodiment of the invention, the portions of the outer skirt arranged between the multiple slots form resilient tongues. Thus, centering of the insert during insertion can be facilitated.
For some applications the insert may comprise at least one second circumferential groove arranged at an outer surface of the inner skirt and extending in circumferential direction of said inner skirt at least along a part of the circumference.
The present invention is also directed to an insert system. Such an insert system typically comprises a panel which has a core structure and a first cover sheet that at least partially covers the core structure and an insert as described herein, the insert being mounted in an opening in the panel. Good results may be obtained if the insert is mechanically interconnected with the panel by means of an interference-fit between the fixation means and the first cover sheet. Good long term insert stability may be obtained if the opening comprises an undercut arranged beneath the first cover sheet.
The present invention is also directed to a method for producing an insert system as described herein. Such a method typically comprises the steps of: providing a panel comprising a core structure and a first cover sheet that at least partially covers the core structure, the first cover sheet inducing an opening in the panel. Providing a specified amount of an adhesive agent into the opening. Inserting an insert into the opening. Establishing a mechanical interconnection between the fixation means and the first cover sheet. As the outer skirt of the insert protrudes in the adhesive agent present in the opening and the fixation means interferes with the panel, an insert system produced according to such a method has a particularly high initial insert stability.
The present invention is also directed to a working head for an insert machine system to process an insert to be mounted in a panel. Such a working head typically comprises at least one insert holding means to bear at least one insert to be mounted in the panel. Further it comprises at least one insert receptive port configured to receive at least one insert to be mounted in the panel and at least one guidance means configured to transport an insert received at the at least one insert receptive port to the at least one insert holding means. In combination with an insert that provides high initial insert stability as described herein, such a working head allows very efficient mounting of even very high numbers of inserts. However, such a working head may also be used for other types of inserts.
According to one aspect of the present invention, a working head is provided that allows a particularly efficient mounting of inserts. Such a working head typically comprises at least one insert holding means to bear at least one insert to be mounted in the panel and at least one insert receptive port configured to receive at least one insert to be mounted in the panel and at least one guidance means configured to transport an insert received at the at least one insert receptive port to the at least one insert holding means. Hence, the total amount of movements of the working head for mounting multiple inserts can be minimized.
For some applications the working head may comprise a working head carrier with which the at least one insert holding means and the at least one insert receptive port and the at least one guidance means are mechanically interconnected.
The working head carrier may comprise a mechanical coupling means configured to mechanically interconnect the working head carrier with a mating coupling means of an actuator of a machine system in a detachable manner. Hence, if required, a working head may easily be replaced for maintenance or adapted for an alternate modus operandi. A variation of a working head may comprise an adhesive dispenser unit configured to provide a specified amount of adhesive agent to an opening of a panel and/or a specified amount of adhesive agent to an insert to be mounted in an opening of a panel. The adhesive dispenser unit may be detachably mechanically interconnected with the working head carrier.
In order to receive inserts to be mounted, the working head may comprise a mechanical insert coupling means which is configured to be mechanically interconnected to a magazine containing multiple inserts configured to provide inserts to the at least one insert receptive port. Alternatively or in addition the mechanical insert coupling means may be configured to be mechanically interconnected to an insert conveying means configured to provide inserts to the at least one insert receptive port. According to a variation of the invention, the working head comprises at least one tool to induce an opening in a panel an insert is to be mounted in.
The present invention is further directed to a magazine for storing inserts to be mounted in a composite panel. A magazine according to the present invention typically comprises at least one storage part configured for storing multiple inserts while having a specific alignment and at least one mechanical coupling means configured to be mechanically interconnected with a mating mechanical coupling means of a consumer device. A magazine typically further comprises at least one insert delivery port configured to deliver an insert from the storage part to an insert receptive port of a consumer device such that the insert has a specified alignment.
Good results may be obtained if the magazine comprises a biasing means inside the storage part for supporting the transfer of the inserts from the storage part through the delivery port into an insert receptive port of a consumer device.
One aspect of the present invention is directed to a magazine system which comprises a first magazine as described herein, whereby the at least one storage part of the first magazine is arranged to store a first type of insert. The magazine system further comprises a second magazine as described herein, whereby the at least one storage part of the second magazine is arranged to store a second type of insert that differs (e.g. in shape and/or dimensions and/or materials) from the first type of insert. The at least one mechanical coupling means of the first magazine and the at least one mechanical coupling means of the second magazine are configured to be mechanically interconnected with the same type of mechanical coupling means of a consumer device and the at least one insert delivery port of the first magazine and the at least one insert delivery port of the second magazine is configured to be mechanically interconnected with the same type of insert receptive port of a consumer device.
The present invention is further directed to an adhesive dispenser unit for dispensing an adhesive agent comprising an adhesive dispenser carrier comprising a mechanical interconnection interface to mechanically interconnect the adhesive dispenser unit with a working head carrier. The adhesive dispenser unit typically also comprises at least one first fluidic port configured to be fluidically interconnected to a source of a first adhesive agent and at least one nozzle to dispense the first adhesive agent.
For some types of adhesive agents, the adhesive dispenser unit may comprises a second fluidic port to be interconnected to a source of a second adhesive agent. Good results may be obtained if the adhesive dispenser unit comprises a mixing chamber that is configured to intermix a first adhesive agent with a second adhesive agent and provide the mixture to the nozzle. For some applications, the first and/or the second fluidic port may be interconnected to a storage tank containing the first respectively the second fluidic agent. Such a storage tank may be interconnected with an actuator of a machine system for producing an insert system, as will subsequently be shown. Alternatively the storage tank may be interconnected with a dispenser carrier or the storage tank may be arranged a distance apart from the machine bed and be fluidically interconnected with the adhesive dispenser via fluidic lines.
The present invention is also directed to a machine system for producing an insert system, which typically comprises at least one holding device for holding a panel and a first working head displaceable with respect to the panel and configured to receive an insertion tool (displaceable with respect to the panel and configured to support an insert to be inserted in the opening. In a variation of the invention the first working head is arranged at a first actuator. The first actuator may e.g. be a bridge of a CNC-router and/or a robotic arm.
In order to increase performance of a machine system, the machine system may comprise a second working head that is arranged at a second actuator and is displaceable with respect to the first working head. The second actuator may e.g. be a bridge of a CNC-router and/or a robotic arm. The second working head may comprise an opening tool to induce an opening into the panel.
The first working head may be a working head as described herein. For some applications, the working machine may comprise an adhesive dispenser unit that is displaceable with respect to the panel. For some applications the adhesive dispenser unit may be mechanically interconnected with the first working head. Good results may be obtained if the adhesive dispenser unit is an adhesive dispenser unit as described herein.
Good performance may be obtained if the machine system comprises at least one fluid line interconnecting the first or the second fluidic port with at least one adhesive storage tank arranged at a distance apart from the adhesive dispenser device and comprising an adhesive agent or at least one component of a multi-component adhesive agent.
For some applications, the machine system may comprise at least one insert conveying means in order to convey at least one insert from a stationary insert receptive port arranged at a distance apart from the working head to the insert receptive port of the working head. The stationary insert receptive port may be arranged at a fixed position at a distance apart from the holding device. Good results may be obtained if the insert conveying means comprises a tube in which one or multiple inserts to be mounted can be conveyed, e.g. by pressurized air.
Alternatively or in addition, the machine system may comprise at least one magazine as described herein and being arranged at the working head and the insert delivery port being interconnected with an insert receptive port of the working head. For some applications a magazine may be arranged at a distance apart from the working head and the insert delivery port being interconnected with an insert receptive port of the working head by means of an insert conveying means.
Although being particularly advantageous for panels and applications as described above, inserts and the devices to mount such inserts according to the present invention are not limited to these and hence may also be used for other types of panels, such as panels used for space technology, e.g. panels comprising a core made from a honeycomb structure made from aluminum and cover sheets made from carbon fiber reinforced plastics.
The herein described invention will be more fully understood from the detailed description of the given herein below and the accompanying drawings, which should not be considered as limiting to the invention described in the appended claims.
The foregoing summary, as well as the following detailed description of the preferred embodiments, is better understood when read in conjunction with the appended drawings. For the purposes of illustrating the invention, an embodiment that is presently preferred, in which like numerals represent similar parts throughout the several views of the drawings, it being understood, however, that the invention is not limited to the specific methods and instrumentalities disclosed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 00412/17 | Mar 2017 | CH | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2018/058001 | 3/28/2018 | WO | 00 |
