US 3298456 A
Description (OCR text may contain errors)
Jan. 17, 1967 c.P1coU 3,298,456
ELECTROMECHANICAL vIBRAToRs Filed June 29, 1964 (23 r q V /2V 9 ,0
`which is not set in a support.
United States Patent O France,` respectively i Filed June 29, 1964, Ser. No. 378,834 Claims priority, application France, July 16, 1963,
s claims. (ci. rs1-.5)
This invention relates to vibration generators intended chiefiy for the generation in the ground of seismic waves and of the type incorporating a matching system constituted by a system of levers the ends of which are connected respectively with a vibratory coil and with the pedestal of the apparatus, which pedestal rests on the ground while an intermediate point of each lever is connected with a station-ary mass incorporating the magnetic circuit producing Ithe field inside which the vibratory coil moves.
In one such type of device, the pivotal connections of the levers the number of which is three for each lever, are constituted by yielding blades set in a support provided for their ends 'and the movements of which are allowed by reason of the elasticity of the medial section of each blade,
Moreover, two of the elastic blades asociated with each lever, to wit Ithose located at the ends of the lever, are disposed in the same horizontal plane while the third blade connecting an intermediate lowing conditions:
(l) The three elastic blades forming the pivotal connections must all be arranged in parallel vertical planes.
(2) The centers of said blades must be accurately aligned.
When the three pivotal blades are arranged vertically and provided they are sufficiently short so as to avoid any bending, which condition is readily satisfied, they form a very` rigid suspension which prevents shifting with reference to the pedestal of the assocated member and movable system.
The alignment of the centers of the blades prevents with an approximation of the first order any modification in the horizontal spacing between one extreme outer blade and `the intermediate movable blade connected with the stationary mass.
On the other hand, the modifications of a second order in said distance do not lead to any objectionable result by reason firstly of their small value and secondly of the -fact that they are readily absorbed through a bending into an S-shape of the extreme vertical blades, which bending cuts out any objectionable straining of the pivotal connections.
An embodiment of the invention will next be disclosed in detail, reference being made to the accompanying drawings wherein:
FIG. l is a general view of a vibrator acconding to the present invention;
FIG. 2 is a top view of the vibrator; and
FIG. 3 a cross-section on an enlarged scale of one ofthe levers with its pivotal elastic blades.
In `the drawing is illustrated a disc secured to the movable coil, a central spindle 9 forming part of the mov- 3,298,456 Patented Jan. 17, 1967 ICC able system including said coil and moving in unison with the latter the pedestal 4 of the vibrator, and the mass 3. Said mass rests on a plate 20 suspended by means of tractionally operating springs 7 the upper ends of which are secured to short uprights 5 connected with the pedestal 4, said uprights extending through openings formed in the plate 20. The levers 11 are shown connecting together the movable system, the mass 3 and the pedestal.
The connection between the lever 11 and the mass 3 is effected by means of an elastic blade 14 extending vertically, said blade being set at its upper end inside the body of the lever 11 while its lower end is set inside a bracket 21 rigidly secured to the mass 3. The elastic blades positioned at the ends of the levers 11 and connecting said ends on the one hand with the movable system and on the other hand with the pedestal are also advantageously arranged vertically.
The vertical elastic blade 22 more particularly has an upper end which is set inside the upper end of the lever 11 while its lower end is set inside a member 23 secured to the spindle 9 carrying the movable system.
Lastly, at the outer end of each lever, an elastic blade 24 is arranged vertically the upper end of which -is set inside the body of the lever 11 while its lower end is set inside a plate 12 rigidly secured by bolts to the uprights 5, whereby said plate 12 forms mechanically part of the pedestal 4 ofthe apparatus.
In FlG. 2, the levers 11 are illustrated by dotted lines. The vibrator includes preferably, but not necessarily three such levers.
The center of each elastic blade is to be considered as formed by the middle point of the portion of said blades which is not positioned inside another part. More accurately, said centers are constituted geometrically by straight lines which are all parallel with one another.
According to the present invention, said centers, that is the three straight lines considered extend accurately in a common plane as shown more clearly in FIG. 3 where the horizontal plane containing the three blades is shown by a dotted line 25 onto which are projected in the plane of FIG. 3 the straight lines defining said centers, to wit: 26 for the blade 14, 27 for the blade 22 and 28 for the blade 24.
As illustrated in FIG. 2, the blades are comparatively broad for the outer ends of the levers and are narrower for the inner ends thereof, which allows said blades to resist more reliably any lateral stresses which may be exerted on the movable system.
Furthermore, the length of the portions of the blades which are not set inside another part is of a magnitude of about 4 mm. whereas the blades have a thickness of a few tenths of a mm.
The vertical arrangement of the blades allows them to absorb without any diiculty any modifications in the spacing appearing, under the action of vibrations, between the movable system including the member 23, the bracket 21 and the member 12.
What I claim is:
1. A seismic vibrator comprising a pedestal adapted to rest on the ground, a mass supported from the pedestal and adapted for containing a magnetic circuit, and a movable system supported from the mass and adapted for containing a coil cooperating with the magnetic circuit, a plurality of levers conected respectively with the pedestal, the mass and the movable system, and three blades associated with each lever and extending in three vertical planes, each blade having one end se-t in the associated lever, said three blades having other ends respectively set in Vsaid pedestal, mass and movable system, said three blades havin-g a central transverse line lying in the same horizontal plane.
2. A vibrator as claimed in claim 1 wherein the blade connected to said movable system is located at one side of the associated lever and remote from the other two blades associated with the same lever.
3. A vibrator as claimed in claim 1 comprising means resiliently supporting said mass on 4said pedestal.
4. A vibrator as clamied in claim 3 wherein the latter siad means comprises uprights on said pedestal, a platform supporting said mass and springs connecting the platform to Isaid uprights.
5. A vibrator as claimed in claim 3 wherein the blades associated with each lever are parallel.
fl References Cited by the Examiner UNITED STATES PATENTS 1,753,368 4/11930 DuBois-Reymond et al. 181-.5 2,620,766 12/1952 Seavey 181-.5 3,143,181 8/1964 Bays et al 181-.5
FOREIGN PATENTS 836,497 4/ 1952 Germany.
To BENJAMIN A. BORCHELT, Primary Examiner.
W. KUJAWA, Assistant Examiner.