Vibration generators

Claim 2

Apparatus for generating seismic vibrations in the ground comprising an electromagnet having a core with an air gap and a winding, a base adapted to rest on the ground to generate vibrations therein, an operating coil which is reciprocated in said gap by electromagnetic action with said electromagnet and means operatively connecting said core, said coil and said base, such that the ratio between the amplitudes of the movements of said coil relatively to said core and of said core relatively to said base is different from unity and is adjustable, said connecting means comprising a plurality of levers and means making pivotable connection between each of said levers, at points spaced along it, with said core, said coil and said base.

Claim 3

Apparatus according to claim 1, wherein said connecting means comprise at least three levers arranged radially about a common axis, means connecting said levers with said core and with said coil, pivot members carried by said base for pivotally supporting said levers and means for adjusting the positions of said pivot members along said levers for varying the ratio between said relative movements.

Claim 4

Apparatus according to claim 1, which includes resilient means carried by said levers for supporting said core with its winding while allowing relative movement between them and said coil.

Claim 5

Apparatus for generating vibrations in a solid medium, such as the earth, comprising a base adapted to rest on the medium and means for producing vertical vibrations of said base to generate vibrations in said medium, said means comprising an annular magnetic core provided with a winding and with an annular air gap, a coil in said air gap concentric therewith and with said core, a plurality of levers arranged radially about the axis of said core and coil, means pivotally connecting the outer ends of said levers with said core and the inner ends thereof with said coil, pivot means carried by said base for pivotally supporting said levers at points between their ends and thereby supporting said core with its winding and sail coil, such that vibrations of said core and coil relative to each other produce vertical vibrations of said base, the relative amplitudes of said vibrations being determined by the relative positions of said pivot points along said levers, and screw threads for moving said pivot points along said levers.

Claim 6

Apparatus for generating vibrations in a solid medium, such as the earth, comprising a base adapted to rest on the medium and means for producing vertical vibrations of said base to generate vibrations in said medium, said means comprising an annular magnetic core provided with a winding and with an annular air gap, a coil in said air gap concentric therewith and with said core, a plurality of levers arranged radially about the axis of said core and coil, means pivotally connecting the outer ends of said levers with said core and the inner ends thereof with said coil, pivot means carried by said base for pivotally supporting said levers at points between their ends and thereby supporting said core with its winding and sail coil, such that vibrations of said core and coil relative to each other produce vertical vibrations of said base, the relative amplitudes of said vibrations being determined by the relative positions of said pivot points along said levers, and screw threads for moving said pivot points along said levers.

Claim 7

Apparatus according to claim 4, wherein said core is formed with an axial bore and a rod is provided which is connected rigidly to said coil and pivotally to the inner ends of said levers, said rod being axially movable in said bore.

Claim 8

Apparatus according to claim 4, wherein a spring is provided between the inner ends of said levers and said core to support the latter while allowing vertical relative movement between said core with its winding and said coil.