Product Code Database
A shock mount or isolation mount is a mechanical fastener that connects two parts elastically to provide shock and vibration isolation.
Isolation mounts allow equipment to be securely mounted to a foundation and/or frame and, at the same time, allow it to float independently from it.
They can be used to isolate the foundation or substrate from the dynamics of the mounted equipment. This is vital on submarines where silence is critical to mission success. Yachts also use shock mounts to dampen mechanical noise (mainly transmitted throughout the structure) and increase comfort. This is usually done through elastic supports and transmission couplings.
Other common examples are the motor and transmission mounts used in virtually every automobile manufactured today. Without isolation mounts, interior noise and comfort levels would be significantly different. Such shock and vibration-isolation mounts are often chosen by the nature of the dynamics produced by the equipment and the weight of the equipment.
Shock mounts can isolate sensitive equipment from undesirable dynamics of the foundation or substrate. Sensitive laboratory equipment most be isolated from shock from handling and ambient vibration. Military equipment and ships must be able to withstand nearby explosions.
Shock mounts are found in some disc drives and compact disc players, where the disc and rainy agreement are held by soft bushings that isolate them from outside vibration and other outside forces, such as torsion. In this case, isolation mounts are often chosen by the sensitivity of the equipment to shock (fragility) and vibration (natural frequency) and the weight of the equipment.
For shock mounting to be effective, the input shock and vibration must be matched. A shock pulse is characterised by its peak acceleration, duration, and shape (half sine, triangular, trapezoidal, etc.). The shock response spectrum is a method for further evaluating mechanical shock.
Shock mounts used to isolate entire buildings from earthquakes are called base isolators.
A similar idea, also known as a shock mount, is found in furniture design, introduced by Charles and Ray Eames. It provides some shock absorption and operates as a living hinge, allowing the seat back to pivot.
Shock mounts are also sometimes used in bicycle saddles, handlebars and chassis.
Early microphones used a 'ring and spring' mount, where a single rigid ring was mounted and carried the microphone between a number of coil springs, usually four or eight. When early microphones were heavy and omnidirectional, this was adequate. However the single plane of suspension allowed the microphone to twist very easily; once microphones started to become directional, this twisting caused fading of the signal. A more three-dimensional and less planar suspension would be required.
Large side-address studio microphone are generally strung in "cat's cradle" mounts, using fabric-wound rubber elastic elements to provide isolation. While the elastic elements can deteriorate and sag over time, the low price of the mount and ease of replacing the elastic elements mean they remain a mainstay despite introduction of elastomer-based designs less sensible to degradation over time.
The same occurs for end-fire microphones, most often employed for location work, however positioning consistency issues in mobile contexts means elastomer-based alternatives have made more inroads: they offer more displacement (positional flexibility) along the prime axis, but better restrict movement along other axis, and have less tendency to keep oscillating after movements, which provide for better control of the microphone's precise position.
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