Boring or penetrating the earth – Tool actuation by reaction of rotating eccentric mass
Reexamination Certificate
1999-11-12
2001-10-16
Bagnell, David (Department: 3673)
Boring or penetrating the earth
Tool actuation by reaction of rotating eccentric mass
C173S049000, C405S232000, C405S249000
Reexamination Certificate
active
06302222
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a device for the transmission and distribution of the vibration and stress exerted by a vibrator on objects such as stakes, tubes or sheet piles, with a view to driving them home, with a horizontal cross-section of dimensions exceeding those of the vibrator.
2. Description of the Prior Art
We know that the vibrators commonly used for this type of application are huge machines comprising at least one couple of offset rotary weights rotated in opposite directions and at a same speed by a motorization.
By way of these arrangements, the centrifugal forces generated by the rotation of the weights add up in a direction defining an axis of work. The centrifugal forces compensate one another in the other directions to cancel one another out in a direction perpendicular to the axis of work.
Usually, the vibrator is suspended at the end of the cable of a crane or similar mechanism, via a device (lifting eye) enabling the vibrator to be displaced vertically.
In the case of the cross-section of the object to be driven into the ground being greater than that of the vibrator, the transmission and distribution of the stress between the vibrator and the object to be driven into the ground are usually performed by a transmission and distribution chamber made of welded sheet steel which is fastened on one side, e.g. by bolting, to the underside of the vibrator (usually a fastening sole plate) and which bears, on the other side, a fastening device that can be adapted to the dimensions of the object to be driven into the ground. This chamber can, e.g., be constituted by two braced parallel plates by a partitioning forming crossbars as represented in U.S. Pat. No. 3,224,514.
When tubular stakes are involved, this device comprises a multiplex device, e.g. a so-called “quadriplex” device, made up of four rail sections or four “T”s bolted to the chambers and a hydraulic clamp mounted slidably with a locking facility on each of the sections or “T”s.
Experience has shown that, due to the intense stress to which it is subjected, the transmission and distribution chamber tends to deteriorate rapidly and must be frequently reloaded or replaced.
Detailed examination of the used chambers reveals that the deteriorations materialised in the form of cracks located along the welding seams and at the base of the protruding portions of the vibrodriver sole plate are due both to the quality of the chamber welding seams and to the heterogeneity in the mechanical behaviour of the chamber at the level of the welding seams. It so happens that this heterogeneity is particularly significant due to the distribution of the reverse bendings at the frequency of the vibrations generated by the vibrator.
OBJECT OF THE INVENTION
The aim of the invention is therefore more particularly to remedy these drawbacks.
To this end, the invention proposes a vibrator of type comprising at inside of a case at least one pair of eccentric-rotary weights driven in rotation, in the opposed direction, at a same speed, by a motorization and least one hydraulic clamp mounted sliding on a profiled rail integral with the lower part of said case.
SUMMARY OF THE INVENTION
According the invention, this vibrator is characterized in that:
the underside of the case is formed by a sole plate whose dimensions sensibly correspond to those of a cross section of the vibrator and on which is assembled by bolting a supporting plate of repartition of vibration and stress whose dimensions are selected so as to exceed the dimensions of said sole plate, and
the said profiled rail presents a “I” shaped cross section and is bolted on said plate.
In cases where it is possible to limit the number of fastening points to two, the rail can be rectilinear and bear two hydraulic clamps.
Conversely, in cases where the object to be driven into the ground is of tubular shape and requires more than two fastening points, the vibration and stress transmission and distribution device can comprise at least one cross-piece made with profiled rails of “I”-shaped cross-section, and assembled by bolting thereof to the supporting plate, each of the branches of this cross-piece bearing a hydraulic clamp. One can readily envisage six rail sections each bearing a clamp when required by virtue of the force to be transmitted.
The device embodying the invention does not therefore require any welding (only the branches of the cross-piece need be welded together where they meet).
Furthermore, the invention derives benefit from the “I”-shaped structure both in terms of the transmission of stress and the bending behaviour.
Likewise, the elastic deformation of the cross-piece adapts excellently to that of the supporting plate and fastening sole plate of the vibrator.
The life span of the device is therefore considerably extended.
REFERENCES:
patent: 3100382 (1963-08-01), Muller
patent: 3224514 (1965-12-01), Hornstein et al.
patent: 3828864 (1974-08-01), Haverkamp et al.
patent: 3920083 (1975-11-01), Makita
patent: 5263544 (1993-11-01), White
patent: 5653556 (1997-08-01), White
patent: 5823272 (1998-10-01), Van Halteren
patent: 5988297 (1999-11-01), Zimmerman et al.
patent: 6073704 (2000-06-01), Yasuoka et al.
Bagnell David
Drucker William A.
Lagman Frederick L.
PTC
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