Feed mechanism for swagable lockbolt collars

An air-driven feeder tool is provided for presenting swagable collars one at a time for placement on the shanks of lockbolts and thereby made ready for the application of a swaging tool. The swaging tool breaks off a pintail from the lockbolt and a vacuum system draws the broken-off pintails through a vacuum device and into a receptacle for safe disposal. The feeder mechanism comprises a magazine holding a supply f side-by-side collars, a presentation piece holding a short working collars and a worker-actuable trigger mechanism between the two queues for transferring collars, one at a time, from the magazine to the presentation queue. Two embodiments of the feeder tool are disclosed, each with a unique trigger position.

FIELD OF THE INVENTION

The invention relates to the installation of lockbolt fasteners having shanks adapted to receive swagable collars and more particularly to a device for presenting collars, in sequence, for location on lockbolt shanks such that a swaging tool can thereafter be applied to secure the collars to the lockbolt shanks. In addition, a device is provided for collecting lockbolt pintails broken off by the swaging tool.

BACKGROUND OF THE INVENTION

Lockbolts of the type having grooved or threaded shanks adapted to receive a swagable metal collar have been known and in widespread use since at least as early as the application date of U.S. Pat. No. 2,521,048 incorporated by reference into expired U.S. Pat. No. 4,852,736 assigned to Huck Manufacturing Company. A typical lockbolt comprises a head and a shank extending from the head. In some cases, the shank is divided into two axially-spaced portions separated by a fracture groove. The portion closer to the head is provided with convolutions or grooves, onto which a collar is swaged. The shank portion farther from the head is called a “pintail” and is broken off by a puller within the swaging tool.

In practice, lockbolts are placed in holes preformed in the workpieces to be joined. Thereafter, a worker assigned to finish the installation of the lockbolts places collars on a number of lockbolt shanks and then applies the swaging tool to set the collars and, where applicable, break off the pintail. This is done lockbolt-by-lockbolt in sequence. A worker typically swages collars in groups of, for example, 6 to 12 collars, and then rests his or her arms by lowering the swaging tool and placing collars on the next set of lockbolts to be finished. We refer to the swaging of a group of lockbolt collars in one tool-handling time as a “cycle”, it being understood that most fastening jobs involve a number of such cycles.

As a practical matter, there are several problems that can crop up in the field. The first arises out of the fact that the article being constructed is sometimes above the worker's head, and the lockbolt shanks may be vertical. Even if a sticky substance like rubberized cement is used to hold the unswaged collars in place, the swaging process may still cause collars to fall off of the lockbolt shanks before they are swaged. In aircraft applications, dropped collars must be scrapped. This not only reduces the efficiency of the lockbolt installation process, but also requires a worker to prevent dropped collars from becoming “foreign object debris” (FOD).

Another problem which often arises in the field is the collection and disposal of lockbolt shank pintails broken off during the swaging step. The typical tool simply ejects pintails without any kind of organization or collection function. Ejected pintails often collect on or around the workpiece or fall on the floor where they present a safety hazard. This is another potential source of FOD. Moreover, normal collection further reduces lockbolt installation efficiency.

SUMMARY OF THE INVENTION

A first aspect of the invention subject matter disclosed herein is a handheld collar feeder tool capable of presenting swagable lockbolt collars singly or serially in groups. In an illustrative embodiment hereinafter described in detail, the collar feeder comprises a handheld tool with a trigger that allows an operator to load a number of collars from a large capacity magazine into a feeder tool queue ready to be fitted into lockbolts. A worker performs the loading function by transferring collars from the magazine into the tool queue using a transfer mechanism built into the feeder tool. The tool is configured to present each collar in the loaded queue in such a way as to allow the worker to place the collar onto a lockbolt shank. The worker then fits a swaging tool onto the collar and swages it onto the lockbolt. The next collar in the loaded queue, if there is one, then moves into the presentation position. The worker completes a cycle and reloads the queue.

In the embodiments described herein, the tool is configured such that the fully-loaded queue holds about 5-15 collars, the number that experience shows a worker can comfortably install in one cycle. The worker can reload the queue, fully or partially, between each swaging cycle simply by activating the tool trigger. These numbers are given by way of example only.

In the form described and illustrated herein, the magazine queue and the feeder tool queue are offset from one another in the queue. Collars are transferred, one at a time, from the top of the magazine to the tool queue by repeatedly depressing a trigger to toggle a slide. Because both the magazine and the handheld tool are connected to a source of pressurized air, the collars in the main magazine are constantly being urged toward the slide mechanism while the collars transferred to the tool queue are constantly being urged toward the presentation end of the tool. The presentation end of the feeder tool can be configured to suit the particular work in progress. Air pressure controls may be provided.

According to a second aspect of the invention, means are provided for systematically collecting and disposing of pintails broken off from lockbolt fasteners on which collars are swaged. In accordance with this aspect of the invention, a swaging/pulling tool that normally ejects broken-off pintails is provided with a conduit which receives ejected pintails, one at a time, and delivers the pintails by vacuum to a container for pintails in an organized and safe fashion in the illustrated embodiment, a conduit runs from the swaging tool to and through a vacuum generator that provides for the movement of pintails from swaging tool to the container.

Other aspects of the invention disclosed herein comprise methods of using the aforementioned collar feed and pintail collection devices, either together as part of a system, or individually.

Still further advantages, features and characteristics of the present invention, as well as methods of operation and functions of the related elements of the structure, and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following detailed description and the appended claims with reference to the accompanying drawings, the latter being briefly described hereinafter.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

Referring to the drawings, and particularly toFIG. 1, there is shown a two-part system for installing lockbolts in a workpiece12that, in this case, is shown simply as two sheets14aand14bof metal to be fastened together. The sheets may, for example, be aluminum sheets. The sheets are joined together by lockbolts16of the “pintail” type. The system for installing lockbolts16comprises a feeder tool10for placing swagable metal collars28(FIG. 5) onto the exposed shanks of lockbolts16, and a swaging tool30having a pintail collection feature including a vacuum conduit64further described herein with reference toFIG. 6. While the system ofFIG. 1works to best advantage when both tools10and30are present, tool10may be used with any swaging tool, and the pintail collection system associated with tool30may be used without the feeder tool10. Tools10and30are provided with pressurized air by a regulated supply100that may be part of a power unit such as the GB904V available from Gage Bilt, Inc. of Clinton Township, Mich.

As shown inFIG. 5, each lockbolt16comprises a shank divided into two axially contiguous grooved portions20and22; the grooves may be annular or helical. The grooves on the upper portion20receive material from metal collars28that are swaged onto the upper shanks by tool30. The grooves on the lower shank portion22provide grip for the puller section of the tool30. Between the two shank portions20,22is a fracture groove24that causes the lower shank portion22to break off as part of the installation process. The material of the collars28is softer than the material of the lockbolt shank such that the swaging tool30deforms the collar radially inwardly into the grooves on shank portion20, locking the collar28to the shank of the lockbolt16and serving effectively as a non-removable nut. The tool30performs the function of pulling on the lockbolt shank while swaging the collar, thus urging the two layers or sheets14a,14btogether. The pulling step ultimately breaks the lower or “pintail” portion22of the shank off at groove24.

As shown inFIG. 1, the lockbolts16are typically arranged on the work12in rows with spacings that can vary considerably but may, in a typical situation, be approximately two to four inches apart. Although only six lockbolts16are shown inFIG. 1, it is to be understood that the normal work situation may involve hundreds of lockbolts to be installed.

Referring toFIGS. 2 through 5, two different feeder tools are shown. Tool10has a front rear-mounted, index finger-operated trigger while tool10′ has a rear, thumb-finger-operated trigger. The difference in trigger position gives rise to other internal differences as hereinafter explained. The overall functions of tools10and10′ are, however, very much the same: they receive collars28from an attached magazine tube32to fill a queue within a curved end piece for placement on lockbolts. InFIGS. 2 and 3A, the collar feed tool10′ comprises a grip body26′ adapted to receive a collar supply magazine in the form of a clear plastic magazine tube32having an interior channel37that is rectangular in cross-section. The magazine tube32is long enough to hold from, for example, 50 to 200 collars in side-by-side adjacent relationship. The interior dimensions of the channel37are such as to provide a low-friction fit, but are tight enough to prevent the collars from tumbling or cocking while within the magazine. The magazine queue is sometimes referred to as a “supply queue” in this document.

Collars28are loaded into the magazine tube32, after which the tube is connected to the tool10or10′ by insertion into a passage39and to a source of air pressure which urges the collar stack toward the tool. The source is preferably regulated so as to neither underdrive nor overdrive the collars toward the tool. The collars are pushed by air toward a transfer mechanism within the grip26′ as hereinafter described. A quick connect feature (not shown) may be used to join the magazine32to the tool in such a way as to hold it securely in use, but allow easy removal for reloading and service.

Referring to the embodiment ofFIGS. 2, 3A and 4B, the tool10′ comprises an upper body30having two main sections: a transfer section38that bolts onto the grip26′ and an integral, curved end piece34′ having an interior channel42long enough to hold a working queue of 5 to 15 collars for a cycle of installations. Transfer section38has a slidebolt passage44to receive a trigger/slidebolt46′ and a bias spring48. Slidebolt46′ has an exposed end and provides a plunger-type trigger an operator can depress repeatedly to transfer collars from the magazine supply queue to the working queue within tool10′. The slidebolt passage44communicates with the magazine passage39and the end piece passage42. The passages39,42are offset from one another. Accordingly, the trigger/slidebolt46′ can transfer collars, one at a time, from passage39to passage42until the end piece34is loaded to the worker's satisfaction. The air pressure bleeding from magazine tube32into tool10′ moves each collar up to the end43of end piece34′.

The number of collars needed to fill the working queue can vary, but can be chosen to match or slightly exceed the number of collars a worker can comfortably swage in a cycle of tool handling. This can be, for example, from 5 to 15 collars. After holding the feeder tool10′ in the left hand and the swaging tool in the right hand and raising both of them to a work position long enough to place and swage 8 or 10 collars, the typical worker is ready to lower the tools and relax his or her arms for a few moments. The working queue in the track piece34′ can be refilled during this rest period. These numbers are all given by way of example and are not limiting.

The slidebolt passage44is closed by jaws60. The channel42is covered by plates56and58. Plate56can be metal or, preferably, a clear plastic that allows the worker to see how many collars are in the working queue. Plate58incorporates an integral retainer spring54that wraps around the open end of the piece34′ to prevent the escape of collars28until the worker pulls the tool10′ away from a lockbolt shank. Both plates56,58are held in place by machine screws. The end of piece34′ is relieved as shown to expose the trough-bore of the collar in the presentation position.

To summarize, the magazine tube32provides a supply queue of collars28to be installed whereas the tool10′ can be loaded up with only as many collars as the worker is comfortable installing in a single cycle of tool manipulations. The trigger46′ is repeatedly pressed by the worker to transfer collars28from the supply magazine32to the working queue in the track piece34′ between each installation cycle or whenever he/she chooses. Air pressure urges the collars from the magazine toward the end of the tool10′. The end piece34′ need not have the curved configuration illustrated, but can be designed to fit a particular job by presenting collars in an orientation that allows them to be transferred onto a lockbolt shank.

FIGS. 1, 3B and 4Ashow a different, preferred embodiment of the tool10. The main difference in this embodiment is the relocation of the trigger46to the front of the tool where it can be operated by a worker's index finger. The trigger46still functions as a spring-based slide to move collars28, one at a time, from the magazine channel to the tool queue42to load the end piece34as desired. As shown inFIG. 3B, the end piece34is reconfigured so the channel42is moved to the rear of the magazine channel or passage39.

Another set of differences between tools10and10′ is shown inFIG. 4A. The channel42′ is covered by a clear plastic plate58′ that extends the full length of the channel42′. In addition, the spring plate54′ is moved to the back side of the end piece34so it does not prevent the operator from seeing if a collar is in the install position. A variable bleed regulator72may be placed on the back of the end piece34′ to adjust air pressure in the channel42′ separately from the pressure in the magazine32. Alternatively, small bleed holes may be drilled into plate58′ to reduce air pressure in channel42′.

The working end of track pieces34and34′ are notched to form top and bottom U-shaped openings43. The top opening43may be chamfered as shown. The vertical height of channels42is such as to accommodate therebetween the collars28with the axis of the throughhole oriented in such a way as to extend through the U-shaped openings43in the end of channels42. Plate58is trifurcated at the right end as shown inFIG. 4Bto form the spring54that wraps around the side of a collar28at the top of the queue to prevent it from going beyond the presentation position at the end of the queue until the operator pulls the tool away from a lockbolt onto which a collar has been placed. The spring is flexible enough to allow this release function, but not so flexible as to allow collars to be blown out by air pressure alone. The springs54and54′ have enough flexibility along their length such that as the worker pulls the feeder tool10away from the lockbolt shank on which a collar28in the staging area has been placed, and the swaging tool30has been brought into place immediately below the collar, the springs54and54′ release the installed collar allowing the swaging tool30to be pushed fully into place around the collar to carry out the swaging operation. The next collar in the queue passage42moves into position at the end of piece34or34′.

Looking toFIG. 6, the swaging/pintail fracturing tool30may take any of a variety of forms. A suitable ejector-type tool is available from Gage Bilt, Inc. of Clinton Township, Mich. and is identified as the GB204SHRB installation tool. The tool has air lines31connected to a power unit to operate a cylinder that controls a collet and a puller in body62, a known manner by operating a trigger61. Jaws60hold a broken-off pintail63auntil the tool30is applied to the next lockbolt. At this time, the entering pintail displaces the pintail63ato the position of pintail63bat which time it is pulled through vacuum conduit64by vacuum from a generator66. The vacuumed pintail goes through the generator66and a second conduit68which empties into a container70that can be emptied from time to time.

During the process of collar installation described above, the pintails of the lockbolts16are fractured off of the shanks of the lockbolts16since they are not needed as part of the installed fastener. In normal circumstances, the fractured pintails are simply ejected through the tool30. In the system ofFIG. 7, the broken-off pintails are collected and deposited in a container70for disposal.

In summary, the feeder tool10or10′ allows a worker to perform a staging function for collars, one at a time, in such a way as to make it easy for the worker to locate those collars, one at a time, on the extending shanks of lockbolts16. This eliminates the practice of hand-placing the collars on a number of lockbolt shanks prior to the application of a swaging tool. After the feeder tool10or10′ has been used to locate a collar onto a lockbolt shank, the swaging tool30is brought into place. The feeder tool10or10′ is withdrawn, the tool30is pushed further onto the shank and the collar is swaged onto the lockbolt shank as described above. The broken-off pintail goes into the ejection chamber of the tool30, forcing the previously broken-off pintail through the tool and into the vacuum system where it is swept into the container70for safe and organized disposal at a later time. This process continues until the feeder queue in end piece34or34′ is empty. The operator then refills the queue with as many collars as he or she feels comfortable installing in a single cycle. The large magazine tube32provides a much longer queue, which the worker needs to refill only after a large number of cycles have been carried out. The worker may perform the foregoing process with tool10or10′ in one hand and tool30in the other hand. As each collar is put in place on a lockbolt shank, another collar takes its place in the presentation queue. The pintail in the tool causes the previously gripped pintail to be pushed into the vacuum conduit64where it is taken to the container70.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law. For example, tools10and10′ may be reconfigured to align the magazine channel with the tool queue so that one trigger activation fills the entire tool queue, thus eliminating the need for repeated triggering action. In this case, the slidebolts simply block or unblock the route from magazine to hand tool as the worker wishes.