A rivet nut is a single-piece tubular rivet with internal threads and a countersunk head that is installed completely on one side of a panel.
Rivet nuts can be made from aluminum, steel, stainless steel, monel, and brass.
Using a pull and push tool, an air motor screws the mandrel into the rivet nut. As the fastener is inserted into the workpiece, hydropneumatic pressure pulls the spindle back. When the set pressure is reached, the air motor is turned on again, pulling the spindle out of the nut.
The process of installing rivet nuts can be automated. The machine automatically installs rivet nuts on parts supplied by a six-axis robot.
Leankeasy is a rivet nut that has matching screws pre-installed. The assembler inserts the two-part fastener into the hole and installs the nut using a standard pneumatic or electric screwdriver. Crimping the nuts and installing the matching screws are done in the same step.
Rivet nuts are widely used by automobile manufacturers to secure parts to structural members.
Automakers are increasingly using hydroformed metal tubing in vehicle designs. Hydroformed parts are lighter, less expensive, and have a higher stiffness-to-weight ratio than stamped and welded metal parts.
This is all well and good until you need to attach other components to the structure using threaded fasteners. Tapping the tube may not be possible because the material may not be thick or strong enough. Self-locking nuts, nut plates, or weld nuts are not suitable because they require access to the other side of the metal for installation. Cage nuts can be used, but they require a square hole and are difficult to install.
This is where rivet nuts come in. Rivet nuts, also known as blind-thread inserts, provide a strong threaded fastener in thin sheets. The fastener was originally developed by BF Goodrich decades ago to attach rubber de-icing boots to aircraft wings. Today, rivet nuts are used in a wide variety of applications.
The rivet nut is a single-piece tubular rivet with internal threads and a countersunk head that is installed entirely on one side of the panel. Like classic blind rivets, the main body of the rivet nut is located on the blind side. The rear flange is large enough to resist pullout even under off-center loading. Since rivet nuts can be installed without touching the sides of the panel, this fastener is ideal for attaching parts to housings, pipes or profiles. The fasteners can be installed on all metals, most plastics and even ceramics.
Blind rivet nuts are ideal for plastics where fasteners cannot be welded or riveted.
Fasteners can be made from aluminum, steel, stainless steel, monel, and brass. The most popular material is galvanized steel, but if you’re particularly concerned about corrosion, you might want to consider stainless steel.Stainless steel rivet nuts are commonly used in solar panel installations and other outdoor applications.
One fastener size can often provide a greater clamping range. For example, PennEngineering’s SpinTite rivet nuts are 0.42 inches long and have a clamping range of 0.02 to 0.08 inches. A rivet nut that is 1.45 inches long has a clamping range of 0.35 to 0.5 inches.
Rivet nuts come in a variety of head types. A wide front flange provides a large bearing surface. This will strengthen the hole and prevent the fastener from being forced through. You can also apply sealant under the flange to protect it from the elements. A thick flange acts as a gasket and provides additional strength when forced through. Countersunk and low-profile heads provide flush or near-flush installation. A wedge or knurling under the head is designed to bite into the mating material and prevent the fastener from turning in the hole.
Wedges are great for soft materials like plastic, fiberglass, and aluminum, However, rivet nuts are annealed and therefore relatively soft. Wedges don’t work well on steel parts.
Rivet nuts also come in a variety of shapes. Standard rivet nuts are cylindrical with a smooth surface, but they are also available in slotted, square, and hexagonal shapes. All of these shapes serve the same purpose: to prevent the fastener from turning in the hole, especially in softer materials like aluminum and plastic.
If installed incorrectly, a round rivet nut can rotate in the hole under high torque.This is not a problem with hex fasteners.
The disadvantage of a hexagonal clasp is that it requires a hexagonal hole. For some manufacturers… it is cheaper to make a round hole than a hexagonal one.
Rivet nuts are also available in open and closed versions. The latter is ideal for applications such as fastening points on the outside of a vehicle, which do not necessarily require appropriate screws. The closed end thus prevents water and dust from entering the component.
Rivet nuts can be installed using hand tools or, more commonly, power tools. The former is similar to a rivet tool. The latter can be hand-held or mounted on a linear actuator for fully or semi-automatic operation. They can also be installed on six-axis robots.
The simplest power tool for setting rivet nuts is a pneumatic “rotary” tool. The fastener is threaded onto a spindle at the end of the tool. The fastener is then inserted into the hole in the workpiece. When the tool is activated, the spindle rotates rapidly and forcefully, pulling the threaded portion of the rivet nut’s shank toward the blind side of the workpiece and forming a bulge around the unthreaded portion. The bulges are pressed against the back of the panel, creating a clamping force that holds the board tightly. Once the rivet nut is securely in place, the spindle rotates in the opposite direction, loosening the nut and leaving the fastener’s internal threads intact.
No additional finishing is required after fixing, even if the parts are varnished or painted. Therefore, rivet nuts can be installed at any stage of the production process.
An upgraded version of the rotary tool is the “rotary pull” tool. As with rotary tools, an air motor screws a spindle into a nut. When a fastener is inserted into the workpiece, hydropneumatic pressure pulls the spindle back a predetermined distance. Once the fastener is secured, the air motor turns on again, pulling the spindle out of the nut.
The third option is the Pull to Pressure tool. This works just like the Rotary Tool, but instead of pulling a set distance, it pulls to a set pressure.
If you’re tightening soft plastics, it’s probably best to use a rotary tool.Pull-and-push tools can cause the fastener to be forced too far into the material. On the other hand, if you’re fastening metal or hard plastics (like glass-filled nylon), pull-and-push tools are more stable.
The latest advance in rivet and nut setting tools is process monitoring. “Rivet nuts are notoriously difficult to set correctly,” says Lanni. “Process monitoring technology can measure how hard the tool pulls and how far it tightens the fastener. It can also count the number of fasteners installed per cycle.”
Rivet nuts are widely used in many industries. This type of fastener is used in a variety of products such as refrigerators, play equipment, office furniture, and bicycles.
In the automotive industry, rivet nuts are used to attach components to dashboards and firewalls. Chassis and body frames also use rivet nuts to attach radiators, roof racks, spoilers, and plastic fenders and panels. Aftermarket hardtops for the Jeep Wrangler are secured with rivet nuts.
In the aerospace industry, they are used inside aircraft to connect overhead bins, armrests, and galley and lavatory components.
The defense industry uses rivet nuts to attach handles and roof racks to military vehicles. In addition, a temporary shelter manufacturer is testing fasteners used to attach components to honeycomb composites.
An electrical equipment manufacturer uses rivet nuts to attach door hinges to large electronic equipment enclosures. The fasteners are also installed on floors, ceilings, and walls to attach components to electronic equipment enclosures.
Although rivet nuts have been around for decades, their technology is not static. Suppliers have recently introduced several new developments.
Last fall, French fastener manufacturer Clufix launched Leankeasy, a rivet nut pre-installed with matching screws. Typically, assembling rivet nuts is a multi-step process that requires specialized tools. With Leankeasy, assemblers can align the parts, insert the two-component fasteners into the holes, and then use a standard pneumatic or electric screwdriver to install the nuts. Crimp the nuts and install the matching screws in the same step.
Fixpal is available in M6 size with a grip range (nut side) of 0.5mm to 3mm and a clamping range (screw head side) of 1mm to 5mm.
Since early 2013, with 10 customers, including Tier 1 and Tier 2 automotive suppliers, as well as lift, tractor and generator manufacturers. Handan Wode fastener had reduced installation costs for these customers by an average of 35%. Tractor manufacturers reported cost savings of 33%, while lift manufacturers reported cost reductions of 70%.
Sherex Fastening Solutions LLC recently introduced another new blind rivet nut called the Riv-Float. Standard blind rivet nuts have threads cut into the rivet body. The Riv-Float blind rivet nut is wrapped around a floating nut. The nut can move .003 inches side to side within the rivet body and float .02 inches radially. This allows countersinks to be inserted at an offset angle to compensate for misalignment of the part and prevent cross threading.
This fastener is available in standard and metric sizes. Standard sizes have a clamping range of 0.027 to 0.15 inches, body diameters of 0.39 to 0.53 inches, and installed lengths of 0.522 to 0.63 inches. Thread sizes are 8-32, 10-32, and 1/4-20. Small flange versions have head diameters of 0.455 to 0.595 inches. Large flange versions are available in head diameters of 0.5 to 0.685 inches.
Metric sizes have a gripping distance of 0.7 to 3.8 mm, body diameters of 9.91 to 13.46 mm and installation lengths of 13.25 to 16 mm. Thread sizes are M4, M5 and M6. Small flange versions have head diameters of 11.56 to 15.11 mm. Large flange versions have head diameters of 13.25 to 16 mm.
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Post time: Dec-19-2024
