This invention generally relates to tools for installing pull type fasteners, and more specifically relates to such a tool where the tool includes a self-aligning feature.
Tools for installing pull type fasteners are standard in the industry. Such tools include riveters and other tools which impart a holding or abutment force to a workpiece while imparting a pulling force on a fastener, thereby installing the fastener with regard to the workpiece. Typically, such tools are handheld and are either manual or hydraulically powered. A typical tool used for such an application includes a cylinder which generates a pulling force on a piston. The piston is engageable with a pull head which transfers the pulling force to the fastener. Examples of such tools currently available in the industry include Textron Aerospace Fasteners' G750A hand riveter and G704B power tool, both of which are configured to work with a plurality of pull heads depending on the specific application.
Rivetless nut plates are also standard in the industry and are typically used in association with fluid tanks, such as fuel tanks or water tanks, for aircraft or the like, for providing a floating, threaded receptacle for receiving a fastener. Some rivetless nut plates are designed such that pull type tools are used to perform the installation. For example, US 2003/0091408 (the publication of U.S. patent application Ser. No. 10/272,721, filed Oct. 17, 2002) discloses a rivetless nut plate where a retainer or attachment sleeve (identified with reference numeral 50 in the Figures of the present application) is positioned in an aperture (identified with reference numeral 52 in the Figures of the present application) in a workpiece (identified with reference numeral 54 in the Figures of the present application), and an enlarged head portion (identified with reference numeral 56 in the Figures of the present application) of a stem (identified with reference numeral 58 in the Figures of the present application) is disposed in the attachment sleeve. Subsequently, a pull tool (such as one which has a front portion 10 such as is shown in
Typically, those rivetless nut plates which are installed using a pull tool are installed using a pull head 12 such as shown in
Installation of rivetless nut plates requires that the aperture in the workpiece be precise. The difficulty of drilling a hole (i.e., aperture) perpendicular to the surface of a workpiece combined with the difficulty of inserting, aligning and installing the rivetless nut plate relative to the hole often adversely affects the quality of the installation. It is especially difficult to drill a precise hole and thereafter properly align a rivetless nut plate in the hole in situations where thin workpieces are involved, in situations where access is limited (i.e., in tight work spaces), in situations where the aperture in the workpiece is oblong, and in situations where some of the structure surrounding the aperture has been torn out during installation. Generally speaking, when a fastener, such as a rivetless nut plate, is poorly installed, the mechanical properties of the fastener are adversely affected. Therefore, it is important to properly align a fastener, such as a rivetless nut plate, for installation in an aperture.
An object of an embodiment of the present invention is to provide a self-aligning tool for installing pull type fasteners, such as rivetless nut plates.
Another object of an embodiment of the present invention is to provide a tool which can be used to efficiently align and install pull type fasteners, such as rivetless nut plates, with minimal operator involvement.
Briefly, and in accordance with at least one of the foregoing objects, an embodiment of the present invention provides a pull head for installing pull type fasteners, such as rivetless nut plates, the pull head is engageable with an installation tool or pull tool and includes a sleeve, a nosepiece on the end of the sleeve, and an insert which extends from an opening in the nosepiece. The insert is configured to enter an aperture in a workpiece and center the pull head relative to the aperture. The insert is shiftable relative to the nosepiece, and preferably includes a taper at its end to facilitate entry into the aperture. The pull head includes jaws which are configured to grab and pull on a stem or fastener, and the insert is configured such that as the stem or fastener is pulled, a surface of the stem or fastener contacts the insert and the insert is pulled along with the stem or fastener. As such, the insert begins in the aperture, but is pulled out of the aperture as the stem or fastener is pulled to effect installation.
As an alternative, the pull tool may include a spring and a nose which are disposed in an insert, wherein the nose extends through an opening in the insert and is shiftable relative thereto, thereby compressing the spring. The nose is engageable with a rivetless nut plate for example, and the jaws are configured to grab and pull on a stem or fastener. The nose is configured to be pulled along with the stem or fastener, thereby compressing the spring. The insert is configured such that as the stem or fastener is pulled further, the nose becomes fully retracted relative to the insert, and the insert is thereafter pulled along with the stem or fastener and the nose.
The organization and manner of the structure and operation of the invention, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the accompanying drawings, wherein like reference numerals identify like elements in which:
While the present invention may be susceptible to embodiment in different forms, there are shown in the drawings, and herein will be described in detail, embodiments thereof with the understanding that the present description is to be considered an exemplification of the principles of the invention and is not intended to limit the invention to that as illustrated and described herein.
As shown in
The spring insert assembly 116 includes an insert 140 which is generally cylindrical having a central throughbore 142. An end portion 144 of the insert 140 preferably includes a taper 146 which is configured to engage a hole 52 in a workpiece 54, as will be described more fully later herein. The insert 140 includes a shoulder 148 which is configured to engage an internal surface 150 of the nosepiece 104, as well as a base portion 152 which is configured to engage an internal surface 154 of the sleeve 102. As such, the insert 140 is generally retained in the nosepiece 104 and sleeve 102.
A cap 156 engages the insert 140 proximate an end 158 of the insert 140, preferably via either a threaded engagement or a press fit. A nose 160 is disposed in the insert 140 and is generally cylindrical having a central throughbore 162. The nose 160 includes a shoulder 164 which engages an internal shoulder 166 provided in the insert 140, such that the nose 160 is generally retained in the insert 140. A spring 168 is disposed in the insert 140, generally between the nose 160 and the cap 156.
To assemble the pull head 100, first the spring insert assembly 116 is assembled. To assemble the spring insert assembly 116, the nose 160 is inserted into insert 140, followed by the spring 168. Subsequently, the cap 156 is engaged with the insert 140, such as via a threaded engagement or a press fit. Once the spring insert assembly 116 is assembled, the spring insert assembly 116 is inserted nose 160 first into the sleeve 102. Then, the spring 114 is positioned behind the spring insert assembly 116, and the collet 112 is pressed against the spring 114. Assembly then continues as with other, conventional pull heads—i.e., the jaws 120 and jaw follower 122 are inserted in the collet 112, and the collet 112 and sleeve 102 are engaged with a pull tool (see
Thereafter, in use, the pull tool is positioned over a hole 52 that has been prepared for fastener installation, and the nose 160 is extended through the hole 52 and the pull tool is pressed against the workpiece 54. As the pull tool is pressed against the workpiece 54, the hole 52 in the workpiece 54 encounters the taper 146 on the insert 140 and the hole 52 moves upwards along the taper 146. The taper 146 works to align the pull head 100 concentrically to the hole 52. Then, the mandrel 58 of an assembled rivetless nut plate, such as the rivetless nut plate disclosed in US 2003/0091408 (the publication of U.S. patent application Ser. No. 10/272,721, filed Oct. 17, 2002), which is hereby incorporated by reference in its entirety, is inserted into the extruding nose 160 (see
When the pull tool is actuated, the mandrel 58 is pulled. Specifically, the jaws 118 lock onto the mandrel 58 as the collet 112 is pulled back and the mandrel 58 is pulled back along with the collet 112. At first, the insert 140 does not move back. Instead, the insert 140 is held flush against the internal surface 150 of the sleeve 102 as a result of compression by the spring 114. The nose 160 retracts first against the spring 168 within the spring insert assembly 116. The inner geometry of the nose 160 interacts with the mandrel base 182 (see
The pull head 100a shown in
To assemble the pull head 100a, the insert 140a and collet 112 are inserted into the sleeve 102. Assembly then continues as with other, conventional pull heads—i.e., the jaws 120, jaw follower 122 and spring 123 are inserted in the collet 112, and the collet 112 and sleeve 102 are engaged with a pull tool.
Thereafter, in use, the pull tool is positioned over a hole that has been prepared for fastener installation, and the end 190 of the insert 140a is extended through the hole 52 (see
When the pull tool is actuated, the mandrel 56 is pulled. Specifically, the jaws 120 lock onto the mandrel 56 as the collet 112 is pulled back and the mandrel 56 is pulled back along with the collet 112. The mandrel 56 pulls the insert 140a back with it (see
Either pull head 100, 100a provides a novel solution to the industry's problem of installing rivetless nut plates into thin structures. The installation tools that are currently being used are using pull heads that result in too many unacceptable installations. The unacceptable installations are tearing into and biting the structure surrounding a hole during installation.
The pull heads described above and illustrated in
Second, preferably a portion of the nose or insert is configured to protrude through the hole prior to installation. This protrusion ensures that the rivetless nut plates, or other general pull type fasteners, are aligned to the center of the pull tool. The protrusions are circular cylinders with an inner curved geometry at the tip that is able to fit in between the rivetless nut plate attachment sleeve and the rivetless nut plate mandrel in order to keep the rivetless nut plate concentrically aligned to the installation tool during installation.
Third, the cylindrical protrusions can serve to verify that minimum or maximum hole size requirements are fulfilled prior to installation. If the hole size is too small, the cylindrical protrusion will not fit through the hole, prohibiting installation. The addition of a sensing element 200, as shown in
While embodiments of the present invention are shown and described, it is envisioned that those skilled in the art may devise various modifications of the present invention without departing from the spirit and scope of the disclosure.
Number | Date | Country | |
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60625152 | Nov 2004 | US |