US2834584A - Pneumatic vibrators - Google Patents

Description

May 13, 1958 L. PER-TROLLE B. BoNDEsoN ETAL 2,834,584

PNEUMATIC VIBRATORS Filed July 6, 1954 United tates Patent PNEUMATIC VIBRATORS Lennart Per-Trolle Bonde Bondeson, Ljunghy, Sweden,

and Eric Fridh, Sao Paulo, Brazil, assignors to Vibro- Plus Corp., Woodside, N. Y., a corporation of Delaware Application `nly 6, 1954, Serial No. 441,542

2 Claims. (Cl. 259-1) The present invention has for its object to eliminaten the difficulties above referred to in connection with pneumatically operated vibrators of the kind stated.

For the object stated, according to the present invention, in a vibrator of the relevant type the roller body is provided with vanes or the like to be acted on by the airstream and so arranged that, primarily, the airstream will cause rotation of the roller body about its own axis and thereby, secondarily, cause the roller body to roll along the circular roller track.

In order to explain the invention and facilitate its carrying into effect, two embodiments thereof will now be described by way of example in conjunction with the accompanying drawing illustrating a pneumatically operated vibrator according to the present invention, and in which:

Fig. l is a cross-sectional view of the first embodiment of the vibrator.

Fig. 2 is a similar cross-sectional view of the second embodiment of the vibrator.

Fig. 3 is a longitudinal section through the vibrator of Fig. 2.

The vibrator of Fig. 1 comprises a casing 1 of substantially cylindrical shape and provided with substantially tangentally extending air inlet openings 2 to the interior of the casing. The air admitted is suitably discharged from the interior of the casing 1 through outlet openings (not shown) in the end walls of the casing. Centrally disposed in the casing and extending the full length thereof is a lixed shaft 3 which supports a tubular roller body 4, the inner diameter of which is substantially greater than the diameter of the shaft 3. The roller body 4 is provided on its periphery with a circumferential series of vaneor blade-like projections 5,

whereby the air under pressure admitted into the casing 1 through the inlet openings 2 will, primarily, impart to the roller body 4 a rotary movement about its own axis. This, secondarily, will cause the roller body to roll along the circular roller track formed by the fixed shaft 3, and the ratio of the inner diameter of the tubular roller body 4 to the diameter of the shaft 3 will determine primarily the actual relationship between the speed of the rotary movement of the roller body 4 about its own axis and the frequency of the vibrations generated. This enables the operating frequency of the vibrator for any given rotational speed of the roller body 4` about its own axis, to be predetermined in a manner known per se by a corresponding choice of the said diametrical rice ratio, and thus it will be possible, even if the velocity of the air passed through the vibrator be kept comparatively low, to obtain a very high frequency of the vibratory movement generated. The rate of air 'flow through the vibrator may, of course, be controlled by means of'a suitable throttle valve, and thus practically any desired vibratory effect is obtainable. It would, of course, be possible to replace the shaft 3 by a couple of trunnions projecting into and supporting the roller body 4.

Referring now to Figs. 2 and 3 of the drawing, the embodiment illustrated therein again comprises acasing 10 having interior walls forming a cylindrical chamber. The casing has end Walls 11 with centrally disposedopenings 12 therein in order to allow air under pressure to pass through the casing 10 in the longitudinal direction thereof. Within the casing 10 a tubular roller body 13 is disposed having secured within its bore a partition 14 extending helically the full length of the roller body 13 and serving as an operating vane for the latter. The external diameter of the roller body 13 is substantially less than the internal diameter of the casing 10, and v latter after having blown longitudinally therethrough.`

When passing in thisway, the air under pressure will act on the operating vane 14 whereby, upon its passage through the assembly 10, 13; the airflow will impart rotational movement to the roller body 13 about its own axis, and this will cause the roller body, secondarily, to perform a rolling or revolving movement in engagement with the inside wall surface ofthe casing 10. Here again the vibration frequency of the vibrator will be determined as to its order of magnitude by the ratio of the external diameter of the roller body to the internal diameter of the casing, in a manner known per se, so that it will be possible, by suitably dimensioning these diameters, to cover a wide range of desired operating frequencies. In addition it will be possible, ofcourse, in a manner similar to that described hereinbefore,l to varythe operating frequency by controlling the air flow through the vibrator casing 10 and roller body 13.

It is to be understood that the invention is` not restricted to the embodiments described hereinbefore in conjunction with the accompanying drawing, since the same is susceptible of several variations and modifications by anyone skilled in the art after having gained knowledge of the inventive concept. Thus the only essential feature of the invention resides in the facts, that, as a primary movement, the roller body is to berotated about its own axis by a flow of air under pressure, and that, secondarily, the said rotational movement is to be transformed into a rolling movement or revolution of the roller body, which presupposes the friction between the roller track surface or race and the roller body to be high.

What we claim is:

1. A pneumatically operated vibrator, comprising in combination, a casing having interior walls forming a cylindrical chamber provided with end walls, said end walls having substantially centrally disposed openings therein to allow the admittance of air to one end of the chamber and the escape of the air from the other end thereof, thus causing a ow of air in the longitudinal direction of the chamber, a tubular roller body having an external diameter smaller than the interior diameter of the chamber within the casing extending the full length thereof, said roller body having secured within itsi bore a partition extending helically the full length thereof, the bore of the roller body being of such Width as to cover said openings in the end walls of the casing in any location of the roller body `within the casing, said partition being adapted to be acted upon by the air and serving as an operating vane of the roller body, whereby, primarily, rotational movement about its own axis is limparted to the roller =body and, secondarily, a rolling movement in engagement 'with the inside -wall surface of the casing is imparted to the roller body.

2. A pneumatica'l-ly operated vibrator comprising means forming a cylindrical chamber, a hollow tubular rolier body inthe chamber having an external diameter Vsmaller thanzthe interior diameter of the chamber, Vmeans -to Vdirect -a `tiow Vof pressurized air longitudinally through `the hollow tubular roller Vbody and said ycylindrical chamber, and `vane means in the hollow tubular roller body responsive to the air flow to rotate the roller body whereby, primarily, rotational movement about its own axis is imparted to the roller body and, secendarily, -a rolling movement in engagement with the inside wall surface of the cylindrical chamber is imparted to the roller body.

References Cited in the file of this patent UNITED STATES 'PATENTS 1,346,221 Liedtke July 13, 1920 2,480,603 Peterson Aug. 30, 1949 2,675,777 Lachaise Apr. 20, 1954 FOREIGN PATENTS 1,056,152 France of 1953 1,110,727 France Oct. 19, 1955

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