Patent Application
20060117547
The present invention relates generally to riveted structures, and more particularly to an integral clamping-and-bucking apparatus for a system, which utilizes a substantially constant force for installing rivet fasteners in a joint.
Aircrafts having riveted structures are well known. Examples of these riveted structures typically include an airframe, an instrument panel, and various other components of the aircraft. These riveted structures typically have sufficient strength for not failing under substantially high static loads and/or substantially high cyclical loads.
Manufacturers typically produce riveted structures in about four general steps. First, the components typically are aligned in a predetermined configuration and clamped with a joint therebetween. Then, a drilling device typically is moved to a predetermined position on the joint for drilling a hole in the components. Thereafter, the drilling device is removed from the components, and the components are separated for deburring, cleaning, and otherwise preparing the hole for receiving a blank rivet. The components typically are then re-assembled with the joint therebetween, and a riveting device is moved to the predetermined position on the joint for forming the rivet in the hole.
One skilled in the art will understand that maintaining proper alignment of the components during the drilling operation and the riveting operation can provide substantially strong riveted joints for not failing under high static loads and/or high cyclical loads.
It would therefore be desirable to provide an integral clamping-and-bucking apparatus for applying rivet fasteners to a joint so as to further improve the robust construction of riveted structures and decrease the manufacturing cycle time of those structures, as well as the costs associated therewith.
One embodiment of the present invention is an integral clamping-and-bucking apparatus for a system, which is utilized for applying rivet fasteners to two or more panels of sheet metal and forming a joint therebetween. The integral clamping-and-bucking apparatus includes a clamping foot for securing the panels in a predetermined configuration for precisely drilling a hole in the panels and riveting the panels at the joint. Also, the integral clamping-and-bucking apparatus further includes a bucking bar for bucking a blank rivet tail that extends from the hole. The clamping foot and the bucking bar are coupled to and actuated by a controller. This controller actuates the bucking bar and the clamping foot for transferring power between the clamping foot and the bucking bar while maintaining a substantially constant total force that is applied to the panels.
One advantage of the invention is that an integral clamping-and-bucking apparatus is provided that minimizes the deflection of the components of the riveted structure during the drilling operation and the riveting operation.
Another advantage of the present invention is that an integral clamping-and-bucking apparatus is provided that minimizes the internal stresses within a riveted structure so as to strengthen the riveted structure for supporting substantially high static loads and/or substantially high cyclical loads.
Yet another advantage of the present invention is that an integral clamping-and-bucking apparatus is provided that utilizes substantially high clamping forces for minimizing interfacial burrs that are produced in the components during the drilling operation and eliminating the need to disassemble the components to remove those burrs.
Still another advantage of the present invention is that an integral clamping-and-bucking apparatus is provided that enhances the rivet shank interference pattern so as to increase the fatigue resistance and the durability of the riveted structure.
Yet another advantage of the present invention is that an integral clamping-and-bucking apparatus is provided that decreases the manufacturing cycle time and the costs associated therewith.
The features, functions, and advantages can be achieved independently and in various embodiments of the present invention or may be combined in yet other embodiments.
For a more complete understanding of this invention, reference should now be made to the embodiments illustrated in greater detail in the accompanying drawings and described below by way of examples of the invention:
In the following figures, the same reference numerals are used to identify the same or similar components in the various representative views.
The present invention is particularly suited for a system and method for utilizing an integral clamping-and-bucking apparatus for installing rivet fasteners in sheet metal joints of an aluminum aircraft skin. In this regard, the illustrated embodiments described herein employ features where the context permits, e.g. when a specific result or advantage of the claimed invention is desired. However, it is contemplated that the integral clamping-and-bucking apparatus can instead be utilized for various other manufacturing processes and/or for producing other airframe structures or various other suitable constructions as desired. For that reason, a variety of other embodiments are contemplated having different combinations of the described features, having features other than those described herein, or even lacking one or more of those features. It is therefore understood that the invention can be carried out in other suitable modes besides those described herein.
Referring to
The system 10 generally includes two or more panels 14a, 14b of sheet metal, an airframe structure 16 with the panels 14a, 14b attached thereto, the CB apparatus 12 disposed adjacent to an inboard side 18 of the panels 14a, 14b, and an integral drilling-and-riveting apparatus 20 (“DR apparatus”) disposed adjacent to an outboard side 22 of the panels 14a, 14b. In other words, the panels 14a, 14b are fastened to the airframe structure 16 and positioned in a predetermined configuration with one or more lap joints 24 therebetween.
The CB apparatus 12 and the DR apparatus 20 are utilized in combination for continuously clamping the panels 14a, 14b in the predetermined configuration with a substantially constant total force. This feature is beneficial for efficiently drilling and riveting a robust joint 24 therebetween. As detailed in the description for
In this embodiment, the CB apparatus 12 and the DR apparatus 20 are integrated within a computer-numerically-controlled system (CNC system) for moving the CB apparatus 12 and the DR apparatus 20 along an x-axis, a y-axis, and a z-axis so as to install rivets 56 in predetermined positions on the joint 24. It is understood that this CNC system 10 is beneficial for providing the consistent, substantially precise manufacture of airframes within a short manufacturing cycle time.
Specifically, as shown in
Each motor 12′, 26′, 28′ and the respective position encoders 12″, 26″, 28″ are coupled to a controller 32 for moving the CB apparatus 12 to the predetermined positions on the joint 24, which require a rivet fastener 56. In this way, as described above, the controller 32 can position the CB apparatus 12 for drilling and riveting the joint 24 with substantially high precision and at a substantially high speed.
Moreover, in this embodiment, the motor 12′ is a pneumatically-driven mechanism, e.g. a pressurized air cylinder, while the other motors 26′, 28′ are electrically-driven servo motors. However, it is contemplated that a screw mechanism, a pulley mechanism, various other suitable drive mechanisms, or any suitable combination thereof can be utilized as desired.
Additionally, each slidable coupling is a ball-bearing slidable coupling (not shown) between the respectable movable components 12, 26, 28, 30. However, it will be appreciated that a pivotal coupling, a rotatable coupling, various other suitable slidable couplings, or any combination thereof can be utilized as desired.
Furthermore, the DR apparatus 20 is slidably coupled to a tray member 34 and one or more motors 20′ for moving the DR apparatus 20 substantially along the z-axis toward and away from the outboard side 22 of the panels 14a, 14b. As detailed in the description for
Additionally, the tray member 34 is slidably coupled to a guide member 40 and a respective motor 34′ for moving the DR apparatus 42 along a y-axis. Also, this guide member 40 is slidably coupled to a pair of rails 42, which are sealingly coupled to the outboard side 22 of the panels 14a, 14b, and a respective motor 40′ for moving the DR apparatus 20 substantially along the x-axis. Moreover, the DR apparatus 20, the tray member 34, and the guide member 40 each have a respective position encoder and laser sensor 20″, 34″, 40″ mounted thereon for detecting the position of the DR apparatus 20.
Each motor 20′, 34′, 40′ and the respective position encoder 20″, 34″, 40″ are coupled to the controller 32 for moving the DR apparatus 20 to the predetermined positions. In this way, as described above, the controller 32 can position the DR apparatus 20 for drilling and riveting the joint 24 with substantially high precision and at a substantially high speed.
Also, in this embodiment, the motor 20′ is a pneumatically-driven mechanism, e.g. a pressurized air cylinder, while the other motors, 34′, 40′ are electrically-driven servo motors. However, it is contemplated that a screw mechanism, a pulley mechanism, various other suitable drive mechanisms, or any suitable combination thereof can be utilized as desired.
In addition, each slidable coupling is a ball-bearing slidable coupling (not shown) between the respectable movable components 20, 34, 40, 42. However, it will be appreciated that a pivotal coupling, a rotatable coupling, various other suitable slidable couplings or any combination thereof can be utilized as desired.
In view of the above, it is understood that the CB apparatus 12 and the DR apparatus 20 can be secured to various suitable computer-numerically-controlled machines for moving the CB apparatus 12 and the DR apparatus 20 with substantially high accuracy and at a substantially high rate for manufacturing the aircraft skin or other suitable riveted structure.
Referring now to
The integral construction of the CB apparatus 12 generally includes a base member 50 with an end portion 44, a clamping foot 46 extending from the end portion 44, and a bucking bar 48 slidably coupled to the base member 50. As detailed in the descriptions for
Specifically, the base member 50 is slidably coupled to the plate member 26 substantially along the y-axis and the z-axis. In this way, the base member 50 is movable to the clamping position (best shown in
With attention to
As best shown in
Referring back to
Specifically, referring now to
As described hereinabove, the drilling device 36 preferably is positioned for forming the hole 54 in a portion of the joint 24 that is substantially concentrically clamped between the indexing foot 52 and the clamping foot 46. In that way, the panels 14a, 14b are substantially supported by the indexing foot 52 and the clamping foot 46 for minimizing the deflection of the panels 14a, 14b by the drilling device 36 during the drilling operation.
Referring now to
Specifically, during the riveting operation, the blank rivet 56 is inserted into the hole 54 either manually by an operator or automatically with a computer-controlled mechanism (not shown). Immediately thereafter, the controller 32 actuates the motor 34′ for moving the tray member 34 along the y-axis so as to accurately position the riveting device 38 at the predetermined position. The controller 32 then actuates the riveting device 38 and a motor 40′ coupled to the riveting device 38 for moving the riveting device 38 along the z-axis and installing a rivet 56 within the hole 54.
Also in this embodiment, the indexing foot 52 has a rigid construction for normalizing the panels 14a, 14b in the predetermined configuration. In addition, the clamping foot 46 is comprised of an elastic deformable material, e.g. polyurethane, for deforming against the panels 14a, 14b as the clamping foot 46 forces the panels 14a, 14b against the indexing foot 52 in the predetermined configuration. It will be appreciated that this feature is beneficial for evenly distributing a clamping force substantially across the portion of the joint 24 that is drilled and riveted. Moreover, this feature locates the panels 14a, 14b in the predetermined configuration without having to precisely align the clamping foot 46 with the indexing foot 52 within substantially small tolerances. It is understood that this feature simplifies the clamping process.
It is contemplated that the clamping foot 46 and/or the indexing foot 52 can have various other suitable constructions and be comprised of other suitable materials for precisely clamping the panels 14a, 14b in the predetermined configuration, minimizing the deflection of the panels 14a, 14b, and applying a substantially distributed clamping force to those panels 14a, 14b.
The bucking bar 48 is slidably coupled to the base member 50 and the respective motor 48′ for moving the bucking bar 48 substantially along the z-axis to the bucking position (best shown in
Also in this embodiment, the bucking bar 48 includes a weight portion 60 of a predetermined mass for assisting the bucking bar 48 in applying a bucking force to the blank rivet tail 62 while the controller 32 actuates the riveting device 38 to apply a multiple impact force on an opposing end of the rivet 56. It is contemplated that the bucking bar 48 can have various other suitable constructions as desired.
In accordance with the invention, as sequentially illustrated in
As a result, the system 10 enhances the rivet shank interference pattern, improves the head-and-shank interference, and substantially strengthens the joint 24. However, it is contemplated that the controller 32 can instead regulate the clamping force and the bucking force according to a variety of other suitable methods.
Referring now to
In step 102, two or more panels 14a, 14b of sheet metal are fastened to the airframe structure 16 and positioned in the predetermined configuration with one or more lap joints 24 therebetween. Also in this embodiment, the CB apparatus 12 and the DR apparatus are mounted to the panels 14a, 14b via the respective rails 30, 42. Then, the sequence proceeds to step 104.
In step 104, the CB apparatus 12 and the DR apparatus 20 are located in a first predetermined position respectively on the inboard side 18 and the outboard side 22 of the panels 14a, 14b. This step is accomplished by actuating the computer-numerically-controlled machine detailed hereinabove. However, it is contemplated that a variety of other suitable positioning mechanisms and methods can be utilized as desired. The sequence then proceeds to step 106.
In step 106, the panels 14a, 14b are clamped in the predetermined configuration. Specifically, in this embodiment, the controller 32 utilizes the computer-numerically-controlled machine for positioning the indexing foot 52 in the predetermined position on the joint 24 and actuating the clamping foot 46 to force the panels 14a, 14b against the indexing foot 52 in the predetermined configuration. The mechanisms utilized for accomplishing this step are exemplified in the description for
In step 108, the drilling device 36 moves to the predetermined position and forms the hole 54 within the panels 14a, 14b while the indexing foot 52 and the clamping foot 46 secure the panels 14a, 14b in the predetermined configuration. The mechanisms utilized for accomplishing this step are exemplified above. The sequence then proceeds to step 110.
In step 110, the riveting device 38 moves to the predetermined position on the joint and installs the rivet 56 in the hole 54 of the joint 24. Specifically, as described hereinabove and sequentially illustrated in
In step 112, the DR apparatus 20 and the CB apparatus 12 are unclamped from the panels 14a, 14b. The sequence then immediately proceeds to step 114.
In step 114, the DR apparatus 20 and the CB apparatus 12 are moved to a second predetermined position respectively on the outboard side 22 and the inboard side 18 of the panels 14a, 14b. Immediately thereafter, the sequence returns to step 106.
While particular embodiments of the invention have been shown and described, numerous variations and alternate embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention be limited only in terms of the appended claims.
