Patent Application
20230131707
This disclosure relates to an installation tool for a pull-type fasteners that produces annular and/or multiple fragments of waste material upon installation, as well as a method of using the same. More specifically, the tool and method here reduce or eliminate unwanted metallic objects and debris from remaining on or in the work piece after the fastener is installed.
Construction rivets are a particular type of pull fastener commonly used in general manufacturing to hold together a plurality of metal sheets, beams, and other work pieces having aligned apertures (either preformed or drilled/created as part of the installation process). These have a pull pin arranged along the rivet's longitudinal axis. That pin is engaged by a specialized installation tool (e.g., pulled out) so that, as the pin is removed, an outer tube or sleeve expands, with one or more enlarged portions clamping the work pieces together.
The installation action for rivets produces waste in the form of the central pin. However, because the specialized tool already grips or engages that pin, riveting tools can modified to collect the discarded pins by pulling or suctioning the pins into a storage compartment on the tool. In this manner, unwanted debris does not collect on the now-joined work pieces.
Aerospace blind fasteners and blind rivets are a more complex fastener (in comparison to commercial rivets) that are primarily used in the aircraft industry. At present, only three suppliers manufacture these specialized components: Allfast (TriMas), Cherry Aerospace (PCC), and Howmet Fastening Systems. Given this small supply chain, the component manufacturers themselves tend to the sole producer of installation tools, and the rigorous quality demands imposed by the aerospace industry make it infeasible to arbitrarily substitute fasteners and/or installation systems.
Aerospace blind fasteners and rivets are constructed from at least three separate parts (e.g., a sleeve, a pull pin, and a locking ring), and one or more of these parts are specifically engineered to fracture or otherwise be removed and discarded (also by way of a specialized installation tool) after the component is installed. For example, these components provide a locking ring or “anvil,” which is effectively an annular washer seated on or formed as part of the head of the pin or bolt in order to facilitate installation of the rivet. As that pin is pulled/manipulated during installation, the anvil fractures at one or more pre-determined fracture points.
As with rivets, this installation process generates numerous small particles and debris. However, unlike the centralized pin collection that can be employed with commercial rivets, the anvil (and possibly other pieces) will separate from the fastener at a location that may not lend itself to the pin collection systems. Further still, some blind fasteners have break bolts where a portion shears or breaks off as part of the installation, thereby giving rise to an additional location (relative to the tool positioning) where fragments and debris may be formed.
If any of this debris (i.e., pins, washers, and/or other metal fragments) is not removed after the rivet or fastener is installed, it creates potential issues when the aircraft later goes into service. And if the joined work pieces seal a portion of the vehicle that will not later be accessible (e.g., the interior void of an aircraft wing, etc.), unwanted noise, unnecessary weight, and even structural damage can result.
At present, extraneous and additional equipment is employed in an effort to reduce or eliminate these particles and debris in aerospace settings. Specifically, clamps including magnetic collector plates have been proposed so as to capture ferromagnetic particles. However, the use of these clamps adds material costs and labor, as they must be installed separately from the installation tool.
For example, U.S. Pat. No. 9,987,714 describes an automated method and system for installing fasteners with frangible collars that are designed to be sheared off by torqueing during the installation process. A vacuum plenum is configured to abut a rotatable installation method so as to collect the unwanted debris. U.S. Pat. No. 7,966,705 and United States patent publication 2013/02399399 provide further insights and background. All of the aforementioned documents are incorporated by reference.
The inventors are also aware of collection collars that can be retrofitted to the installation tool/system at least one aerospace fastener provider. Here, a magnet is over-fitted around the muzzle of the tool in which pulling head is positioned. This adds size and weight to the system, and the reliance on a single magnet makes it critical to align the tool during installation, as gravity alone must cause the magnetized anvil to fall close enough to the collar.
In view of the foregoing, there is a need for a fastener, installing tool, system, and method all of which (singly or in combination) reduce or eliminate debris and particulates created during fastener installation/use without the need for additional clamps or rotating/moving parts. A system that was not reliant upon creating vacuum suction around the work piece and tool (or debris removal system) is also needed. Lastly, a system that is handheld, portable, and preferably retrofitted to existing tools would be welcomed.
The invention takes several different aspects, all of which are centered around the ability to provide for the capture of annular and fragmented debris created during the installation of aerospace fasteners in a hand-held tool and/or to retrofit an existing system for the same purposes. The collection methods include provision of magnets at spaced-apart points where the tool head engages the fastener pin. An integral collection bin can also be provided, as well as a collapsible basket, both of which also have magnetic catch points. Vacuum systems can be provided to further enhance and improve the collection system.
The appended drawings form part of this specification, and any information on/in the drawings is both literally encompassed (i.e., the actual stated values) and relatively encompassed (e.g., ratios for respective dimensions of parts). In the same manner, the relative positioning and relationship of the components as shown in these drawings, as well as their function, shape, dimensions, and appearance, may all further inform certain aspects of the invention as if fully rewritten herein. Any printed information on/in the drawings form part of this written disclosure.
In the drawings and attachments, all of which are incorporated as part of this disclosure:
Operation of the invention may be better understood by reference to the detailed description, drawings, claims, and abstract—all of which form part of this written disclosure. While specific aspects and embodiments are contemplated, it will be understood that persons of skill in this field will be able to adapt and/or substitute certain teachings without departing from the underlying invention. Consequently, this disclosure should not be read as unduly limiting the invention(s).
As used herein, the words “example” and “exemplary” mean an instance, or illustration. The words “example” or “exemplary” do not indicate a key or preferred aspect or embodiment. The word “or” is intended to be inclusive rather an exclusive, unless context suggests otherwise. As an example, the phrase “A employs B or C,” includes any inclusive permutation (e.g., A employs B; A employs C; or A employs both B and C). As another matter, the articles “a” and “an” are generally intended to mean “one or more” unless context suggest otherwise.
Similarly, terms such as “user,” “operator,” and the like should be understood as being interchangeable throughout the subject specification, unless context suggests a particular distinction among the terms. Also, the terms and methods herein may refer to human entities or automated components such as automated robotic assembly devices, including those being controlled by a user, supported through artificial intelligence (e.g., a capacity to make inference), programmed for a particular user, or otherwise. For instance, examples describing installing a rivet may include a human user with a hand held installation device, a human operating a robotic arm having an installation device, an automated machine that utilizes an installation device, etc..
As used herein, a fastener may refer to various types of rivets, screws, bolts, or the like. Such fasteners may comprise metals, plastics, or other materials. For example, fastener may refer to a cylindrical rivet comprising a metal body (e.g., aluminum, steel, etc.). Moreover, embodiments may refer to a specific type of fastener for simplicity of explanation. As such, disclosed aspects may be applicable to various other types of fasteners.
U.S. Pat. Nos. 5,350,264; 5,634,751; 7,857,563; 8,322,015; 10,760,605; and 10,941,799, as well as United States Patent Publications 2002/0164203; 2005/0163586; 2014/0201974; 2016/0102695; 2019/0048193; 2019/0195260; 2019/0390697; and 2020/0049185 and international patent publication WO 2020/056244, all disclose various designs, tools, components, and methods relevant to pull type and other fasteners. Accordingly, these disclosures are all incorporated by reference, so as to more fully inform this disclosure and its inventive features.
The assembly of aerospace structure components employs the use of many fasteners, which will be described in greater detail below. Fastener selection is typically based upon many factors that include desired mechanical properties, accessibility to work piece, and cost. Three exemplary fasteners include aluminum lock bolts, blind fasteners, and solid rivets. These two fasteners each provide benefits and limitations to their use. Alternatives to these fasteners exist but present different limitations to their use. In all cases, aerospace grade fasteners can and must be distinguished from general construction components because the aerospace versions must be of exceptionally high quality, both in terms of the grade of materials and the reliable performance installation of the fasteners themselves. Thus, even where analogies might be drawn between previously known general construction rivets having frangible and discarded components, the conditions in which those general construction rivets are implemented and installed allow the user a much wider degree of freedom (in terms of disposing of debris and selecting the fastener in the first instance) than can be available in aerospace installations.
A lock bolt fastener is a two piece design comprised of a pin and a swageable locking collar. The lock bolt type fasteners are non-blind fasteners. The installation of this fastener is accomplished by inserting a pin into an aperture formed through work pieces to be joined. The locking collar is applied to the pin from the opposite side of the work. An installation tool pulls the pin so that the nose of the tool swages the collar onto the pin creating a mechanical lock with the pin. The pull portion of the pin then fractures and is discarded. One of the disadvantages to the use of lock bolts is that both sides of the work to be joined need to be accessible for installation of the fastener.
Solid rivets are a single component fastener, generally made from aluminum alloys, having a head and a shank. Solid rivets are installed by inserting the fastener into an aperture formed through work pieces to be joined. The rivet is restrained on the head side and force is applied to the opposite side, permanently deforming the terminal end of the rivet. One of the disadvantages to the use of solid rivets is that these fasteners are non-blind so that they require that both sides of the work to be joined are accessible to install the solid fastener
Blind fasteners are a particular type of pull-type fastener that may be used where there is limited operating room. Also, these can reduce installation and/or time in comparison to two-piece non-blind fasteners, and they tend to be more readily and cost effectively adapted to automated or robotic installation than would be a two-piece system.
Blind fasteners based on rotary or pull-type actuation are particularly useful. Both are typically composed of multiple components which move and/or separate relative to one another, thereby creating the potential creation of unwanted debris being deposited onto/into the work pieces.
The rotary fasteners provide the desired mechanical properties and require only accessibility to one side of the work piece. The fastener is inserted into the work and the installation tool actuates the pin in a rotary manner. Depending on the particular fastener, a sleeve component deforms against the side opposite of the fastener head (e.g., the blind side) joining the work and applies preload. A drive portion of the pin fractures and is discarded. These fasteners tend to be more costly (e.g., such as due to materials used, manufacturing costs, or the like) and complexity in manufacture. Prevention of galvanic corrosion between the fastener and work material requires coatings that are costly and/or environmentally unfriendly.
Pull-type blind fasteners generally include a drive anvil or washer, a pin and a sleeve. The washer and sleeve have an axial bore therethrough. The pin is assembled through the sleeve and washer. A hollow cylindrical sleeve surrounds the pin between the washer and a head of the pin. In installation, the fastener is aligned in holes in work pieces. As the bolt is drawn through the bore of the nut, the sleeve is pushed by the bolt head and is deformed against the workpieces thus locking the fastener in position.
Once locked, a portion of the pin above the work pieces is removed and discarded, usually by way of a specialized installation tool. This portion typically breaks off from the remainder of the pin. This action can lead to small particles and other debris becoming separated from the final, installed fastener. If this debris is not removed, it can create unwanted hazards and issues in an aircraft or other vehicle, especially to the extent the joined work pieces seal an inaccessible part of the vehicle (e.g., the interior void of an aircraft wing, etc.).
There are two main sources of foreign object debris (FOD) created during installation of aerospace fasteners: portions of the stem and, separately, portions of the driving anvil. These portions fall away from different physical locations on the fastener so that it is not possible to rely on a single, confined particulate collection point or system.
Consequently, the inventors propose to rely upon magnetic and/or vacuum-assisted functionality provided on the installation tool. The magnet portions may be friction fitted into slots, grooves, or other surface formations on the installation tool nose piece, with the magnet being sufficiently strong enough to draw and adhere falling particulates. The particulates can then be brushed or dislodged from the magnets allowing to collect the discarded objects and, possibly, reuse/reinstall the magnet on additional fasteners.
A similar approach can be employed with the installation tool. Here, magnets or suction/vacuum systems would collect the particulates in a designated pouch. The pouch can be positioned on the tool so as to allow gravity to at least initially direct the particulates into the pouch. In other aspects, a simple magnetic plate could be used (with a similar approach as above, in that the magnet can removed, cleaned, and/or replaced on the tool during installation processes).
With reference to
Head 10 includes a pin aperture 11 sized to receive the proximal end of the pin 21. Conventional means (not shown) are provided within the driving mechanism of the tool to pull and/or twist the pin 21 until the proximal end shears off (also see
Retaining a narrow and comparatively elongate profile to the head 10 is critical to certain aspects of the invention. That is, the nature of how aerospace fasteners are deployed requires the user to be able to maneuver and manipulate the tool in compact spaces. Thus, the inventors appreciated that mechanisms like the one contemplated in U.S. Pat. No. 9,987,714 may not be practical, especially with regard to the installation of blind bolts and rivets having anvils.
As seen in
Magnets may be temporary/permanent magnets or electromagnets. When the latter are employed, the electromagnetic coils may be coupled to the power source driving the hand held tool, with actuation of the magnets synchronized to the trigger actuator used to engage/install the fastener. Other appropriate magnet types include neodymium iron boron, ceramic, ferrite, alnico, or samarium cobalt. If electromagnets are employed, the system can be configured to periodically release FOD by shutting off the current (i.e., temporarily releasing magnetism), while embodiments relying on the pneumatic removal of FOD can further synchronize with the electromagnet activation/deactivation so that suction is applied when magnetic force is released. In all cases, the strength of the magnet should be sufficient to capture FOD but without interfering (or becoming attracted to) the work pieces being joined.
In the arrangement illustrated in
Because installation tools are typically employed to install a plurality of fasteners in quick succession, simply providing magnets may be insufficient to meet the practical reality in using these tools. Therefore, as a further aspect, the inventors propose a number of collection systems as shown in
For example, a collection bin 200 can be affixed to the head 100 by way of a screw or snap-fitting, although other attachment means are possible. The head 100 reciprocates within an upper engagement chamber 210. At opposing ends of the chamber 210, a fastener aperture 212 and head aperture 214 are aligned along the axis of reciprocation for the head 100. As seen in
As seen in
Because the head 100 may slide (or be forced by the regular reciprocating motion of the tool) along the axis of the apertures 212, 214, any FOD 99 (e.g., anvil, particulates, etc.) captured by the magnets 130 on the head 100 can be dislodged by the inner facings of the chamber 210.
A collection compartment 220 is provided underneath or partially or completely around the engagement chamber 210, with a slot 230 configured to allow dislodged FOD to fall off of the head 100 and into the compartment 220. The compartment 220 may have an arcuate or annular shape, with a continuous connection slot 230 or series of individual slots (not shown).
The compartment 220 may be permanently affixed to the engagement chamber 210 or, more preferably, the compartment 220 has a modular construction that allows for quick and easy “change out” once it is filled. Thus, the compartment 220 may be snap or slide fitted, via bead, grooves, slots, and the like provided on the interfacing surfaces of the housings forming the chamber 210 and compartment 220.
In other aspects, the compartment 220 may be formed as or connected to a pneumatic collection system. This pneumatic system operates at a pressure differential (e.g., a partial vacuum) to remove FOD 99 from the chambers 210, 220. Notably, because the pressure is only needed to remove already detached FOD, it is not necessary to form a seal (or even provide particularly strong suction) between the workpiece and the tool/head 100. A pneumatic connection housing 240 can be provided on the tool and adjacent to the compartment 220. A vacuum line draws airs and FOD 99 out of the compartment 220 and into a larger storage space in the housing 240. Additionally or alternatively, the line 241 can pull FOD 99 completely out of the housing 240 for final disposal or recycling, with a similar line 242 possible for removing discarded portions of pins 21.
In
In
A further iteration of the collection compartment is shown in
Notably, all of the foregoing aspects can and should be implemented or retrofitted onto existing, hand-held tools. This approach avoid the need to create a separate machine or platform, so that current production lines will not be disrupted. Further, because the system uses magnets arrayed completely around the head 100, the system is highly effective at capturing all FOD. Further, the system is not dependent upon creating suction around and between the work piece and the tool.
What has been described above and in the attachments include various examples. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present specification, but one of ordinary skill in the art may recognize that many further combinations and permutations of the present specification are possible. Each of the components described above may be combined or added together in any permutation to define embodiments disclosed herein. Accordingly, the present specification is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.
This application claims priority to U.S. provisional patent application Ser. No. 63/270,792 filed on Oct. 22, 2021, which is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 63270792 | Oct 2021 | US |
