Robust low profile shaker

An electromagnetic apparatus for producing a vibratory motion in response to a signal from a power source, comprising:

• a bottom assembly comprising;
• a rigid base plate;
• a magnet positioned on the base plate for producing a magnetic field;
• at least one pole piece for interacting with the magnet to modify a characteristic of the magnetic field;
• and
• at least one pin fixedly connected to the base plate for receiving at least a portion of a spring assembly whereby the pin provides transverse support to the spring assembly;
• a top assembly opposing the bottom assembly, said top assembly comprising;
• a rigid top plate comprising a substantially planar surface corresponding to a surface defined by the base plate for supporting at least a portion of an item of furniture;
• and
• a coil portion for receiving the signal from the power source and interacting with the magnetic field to produce the vibratory motion;
• a spring assembly situated at least partially on the periphery of the bottom assembly and operative with the top assembly and bottom assembly to resiliently support the top plate in the presence of the at least a portion of an item of furniture placed on the top plate, wherein the spring assembly is configured such that substantially uniform resilient support is provided to the top plate when the at least a portion of an item of furniture is placed on the top plate in a location outside the center of the surface of the top plate;
• and
• a bushing material for providing transverse support of the top plate with respect to the base plate when a transverse force is exerted on the top plate.