Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
2000-02-17
2001-10-09
Hughes, S. Thomas (Department: 3726)
Metal working
Method of mechanical manufacture
Assembling or joining
C029S243530, C081S180100, C072S478000
Reexamination Certificate
active
06298543
ABSTRACT:
This invention relates to a modified tool head and method for use thereof for riveting tools which can reduce the possibility of marring of the rivet or the material to be riveted adjacent the rivet.
BACKGROUND OF THE INVENTION
This new conceptual product design resulted from personal experience in the aviation sheet metal industry. Differences in hardness factors between the job tool [rivet gun and detachable snap head] and the material being used [rivets (aluminium) and skins (usually aluminium but often composites)] have always necessitated the continual need to intermittently construct a taped protective surface for the snap portion of the tool. This tool is used for many hours each day. Without protection, the materials utilized in the job often become damaged and must be replaced, thus resulting in significant wastage of both material and work hours. I have clearly observed that this difficulty is experience by virtually all of the individuals who utilize this riveting tool.
Universal (round head) rivets are installed in a variety of methods, but can be divided into two groups, the squeeze type and the impact type methods. The squeeze riveter is either stationary or portable, normally relying on air pressure to compress a rivet. One jaw is stationary and serves as a bucking bar against the manufactured head while the movable jaw upsets the shank and forms the shop head. Compression riveters have their own special rivet sets.
An impact/rivet gun is a piston type tool. Air pressure drives a piston which in turn hammers on a snap or tool head in the rivet gun. In the riveting operation the shop head (or under surface of the rivet) is formed by placing a hardened steel bar against the exposed rivet shank to counter the pressure being applied by the rivet gun. This procedure forms the shop head. The accessibility of the rivets to be installed is not always ideal, thus rivet snaps are available in various sizes, shapes and lengths.
A technician in the field installing rivets is highly skilled, but an ongoing problem occurs. A wide variety of influences, but predominantly the angle of attack (i.e. the snap not being exactly perpendicular to the rivet and skin surface), causes marring, that is, marking or denting (smiles) to occur on either or both the skin and rivet head. This damage also removes the protective coating on the rivet and/or the skin surface thus increasing the chance of early corrosion. In severe cases the fasteners and/or the damaged skin must be repaired or replaced. Of more serious concern is the occurrence of stress risers which may result in cracks potentially leading to a compromise of structural integrity.
For years, in an attempt to reduce or avoid this problem technicians in the field have been applying tape (masking, electrical etc.) to the end of the rivet snap to provide a buffer zone. Taping is limited in that only a small number of fasteners can be installed before the snap requires re-taping. This procedure is quite time consuming and messy due to the adhesive.
It is known in regard to tools for impacting flush type rivets, that is rivets which provide a flat face coplanar with the finished material, that the tool face include a recessed rubber ring around the edge of the flat tools face. The majority of the rivet is therefore impacted by the metal inner portion of the tool head while the surrounding rubber ring which is flush with or slightly proud of the metal surface inhibits marring of the material surrounding the rivet.
A similar arrangement, in which the angle of attack can be varied, includes a tool head which is mounted on a support ball so that it can be swivelled to the required angle on the ball. The tool head is surrounded by a rubber sleeve which again is flush with the end face or slightly proud of the end face so as to provide a ring surrounding the end face.
In both of these arrangements, the rivet is impacted by the metal tool and the rubber ring surrounds the tool to reduce the possibility of marring.
However the solution is unsuitable for recessed head of a tool used for domed rivets or universal rivets and no solution for the marring effect of the tool for such rivets has been provided.
SUMMARY OF THE INVENTION
It is one object of the present invention to provide an improved method and tool for use in riveting which inhibits the possibility of marring of the rivet or surrounding material.
According to a first aspect of the invention there is provided a riveting tool comprising:
a tool head shaped and arranged for engaging and driving a rivet head by pressure or impact;
the tool head including a generally cylindrical body with a peripheral wall and a front face for engaging the rivet head, the front face having a central portion and a peripheral portion at or adjacent the peripheral wall;
and a sheath engaged over the tool head;
the sheath being integrally molded from a plastics material;
the sheath having a generally cylindrical sleeve portion engaged over the peripheral wall of the tool head and extending thereon from the front face to an edge of the sleeve portion partly along the tool head;
the sheath having a front portion shaped to cover at least the peripheral portion;
the sheath being shaped to provide a readily removable and replaceable friction fit on the tool head so that the cylindrical sleeve portion is slideable over the front face onto the cylindrical portion to be maintained thereon by the friction fit;
the sheath being arranged to allow forces to be communicated from the tool head to the rivet head to effect driving of the rivet for attachment of the rivet to a material to be riveted and the sheath being arranged such that the front portion at least at the peripheral portion is sufficiently thick to inhibit marring of the rivet and the material adjacent the rivet by the peripheral rib.
Preferably the sheath at the front face has a thickness less than 0.020 inch.
Preferably the sheath at the front face has a thickness which is sufficiently thin such that compression thereof by the forces is insufficient to cause material to be forced to the peripheral wall to cause splitting thereof.
Preferably the sheath is fully closed at the front portion.
Preferably the front portion of the sheath includes a central opening inward of the peripheral portion.
Preferably the sheath has a peripheral rib at the edge remote from the front portion for manually grasping the sheath.
Preferably the sheath has at least one raised projection on an inside surface thereof for engaging and providing a friction fit with the cylindrical portion of the tool head.
Preferably the thickness of the front portion of the sheath is substantially constant with an inside surface of the front portion directly in contact with the front face of the tool head.
Preferably the front face of the tool head includes a central recess at the central portion and a forwardly projecting peripheral rib at the peripheral portion and wherein the peripheral portion of the sheath covers the peripheral rib.
According to a second aspect of the invention there is provided a method of applying a rivet to a material to be riveted comprising:
providing a rivet having a shank and a rivet head;
providing a material to be riveted having a hole therein for receiving the shank of a rivet;
providing a riveting tool comprising a tool head shaped and arranged for engaging and driving the rivet head by pressure or impact;
applying forces to the tool head to apply forces to the rivet head to attach the rivet to the material at the hole;
and preventing marring of the rivet and the material adjacent to the rivet by engaging a sheath over the tool head during the application of forces to the rivet head;
the tool head including a generally cylindrical body with a peripheral wall and a front face for engaging the rivet head, the front face having a central portion and a peripheral portion at or adjacent the peripheral wall;
the sheath being integrally molded from a plastics material;
the sheath having a generally cylindrical sleeve portion engaged over the peripheral wall
Bartlett Judith Gertrude
Shore Douglas A.
Battison Adrian D.
Hughes S. Thomas
Nguyen T.
Williams Michael R.
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