US3796411A

US3796411A - Nutating disc vibrator

Info

Publication number: US3796411A
Application number: US00288291A
Authority: US
Inventors: F Gartner
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-07-20
Filing date: 1972-09-11
Publication date: 1974-03-12
Anticipated expiration: 1991-03-12
Also published as: IT965358B; DE2235585A1; AT316847B; NL7212587A; SE382568B; CH539456A; JPS4937924A; JPS564401B2; FR2193335A5; GB1354647A

Abstract

A nutating disc vibrator includes a nutating disc mounted within a cavity in a casing and guided by cooperating surfaces of the cavity. An inlet for a working fluid directs the working fluid along a path substantially in the plane of symmetry of the nutating movement and the working fluid itself is conducted only through stationary parts of the casing.

Description

United States Patent 1191 -Giirtner Mar. 12, 1974 NUTATING DISC VIBRATOR 2,960,316 11/1960 McKellar 259/1 R 1 1 Friedrichstrasse 21, $52233? 311353 51122511111111; ..'.1"..i ."5'/13 7501 Bruchhausen, Germany [22] Filed: 1972 Primary Examiner-R0bert W. Jenkins [21] App]. No: 288,291 Attorney, Agent, or Firm-Wenderoth, Lind & Ponack [30] Foreign Application Priority Data 7 A CT July 20. I972 Germany 2235585 [57] BSTRA A nutating disc vibrator includes a nutating disc 512] 259/1 R, 227D]? 43 mounted within a cavity in a Casing and guided by operating surfaces of the cavity. An inlet for a working 1 0 can l1 8 8 fluid directs the working fluid along a path substan- 7 tially in the plane of symmetry of the nutating movement and the working fluid itself is conducted only [56] References cued through stationary parts of the casing.

UNITED STATES PATENTS 2,778,612 1/1957 Peterson 259/] R 19 Claims, 8 Drawing Figures Mex. \r 1 NUTATING DISC VIBRATOR This invention relates to a vibrator including a cavity and a nutating disc within the cavity driven by a working fluid and guided by cooperating surfaces within the cavity.

Many forms of vibrators for compacting pourable mouldable masses such as concrete prior to hardening are known.

In pneumatic vibrators an inertial element is moved by compressed air to cause the vibration. These known vibrators, however, have required valve means for controlling the compressed air and the valve means 'is not only liable to be troublesome but tends to be expensive.

Also known are nutating disc motors but these also have required valve means to control the entry and exit of the working fluid, the valve means being contained partly within bearing means for the disc itself.

It is an object of the present invention to provide a vibrator comprising an inertial element which can be driven by a working fluid within a cavity in a casing and wherein no valve means is required to control the entry and exit of the working fluid to and from the vibrator.

To this end, the present invention provides a vibrator comprising a casing, a cavity within the casing, nutating inertia discmeans in the cavity guided by cooperating surfaces of the cavity, and inlet means and outlet means for conducting a working fluid into and out from the cavity wherein said inlet means is positioned in a wall of the casing to direct the working fluid into the cavity along a path lying substantially in the plane of symmetry of the nutating movement of said disc means whereby working fluid directed into the casing by the inlet means will impinge upon the disc means to cause nutating movement thereof,the inlet means and the outlet means further being arranged to conduct the working fluid exclusively through stationary parts of said casing.

The location of the inlet means assists in starting the vibrator and the fact that the working fluid is conducted only through the stationary parts of the casing promotes trouble free operation. Conveniently the working fluid is a compressed gas such as nitrogen bu't compressed air is also satisfactory.

The dimensions of the vibrator may vary depending upon the particular application for the vibrator. Furthermore, the speed of nutation of the disc and hence the frequency of vibration can be steplessly varied within a wide range by changing the pressure and consequently the flow rate of the working fluid, for example between and 500 cycles per second. The pressure of a compressed air supply may be varied between 0.5

tion of maximum inclination wherein its axially opposite faces make linecontact each with a respective generator of a respective one of the conical portions. It is also preferred that supporting elements are provided at the apices of the conical portions to ensure that the disc will be tilted when it comes to rest and this greatly facilitates starting.

In one preferred embodiment the two supporting elev ments are ball ended rods with the'balls thereof re ceived in sockets in axially opposite faces of the disc and with the rod portions thereof received in conical recesses in the apices of the conical portions. This is a particularly good arrangement for ready starting.

In an alternative embodiment the disc is mounted on a central ball which is retained in sockets at the apices of the conical portions. Preferably the central ball is movably received in a central opening in the disc and in order to minimise friction the ball is less than one tenth of the diameter of the disc.

In another 'useful'embodiment of the vibrator the disc is carried on ball bearing means or a cylindrical roller bearing on a central shaft carried at its ends in the apices of the conical portions.

The outlet means may suitably comprise a plurality of channels connected in parallel with the sum of their cross-sections selected in accordance with the required cross-section of the outlet means. Such a subdivision into separate channels can eliminate the need to provide filter means for preventing the ingress of dirt.

Withadvantage the disc may have conical recesses in its axially opposite faces in conformity with the conical portions of the cooperating surfaces or it may be a flat and I2 atmospheres. The proposed vibrator is particularly useful in association with shuttering and formwork in building construction, though in suitably modified form it can also be used for purposes such as massage and the like. In one preferred embodiment the cooperating surfaces in the cavity are so shaped that the outer periphery of the disc is in rolling engagement therewith and this arrangement is particularly suitable for trouble-free operation of the vibrator.

In order to enhance the running of the vibrator, at least one side of the disc may be supported by the easing. Preferably the cooperating surfaces include two mirror-symmetrical coaxial conical portions projecting inwardly of the cavity. The disc is then positioned between the conical portions so that it can tilt to a posicircular disc.

To assist starting the vibrator, the periphery of the disc may be chamfered to a sharp edge, and preferably the chamfering will be symmetrical on both sides of the disc. It is also contemplated that a channel be provided in the casing wall adjacent the inlet means within the cavity, this channel being equal in length to about half the thickness of the disc. Such a channel extending parallel to the direction of rotation of the disc will provide a satisfactory distribution of working fluid within the cavity and will assist starting of the vibrator.

The casing of the vibrator may comprise two elements joined in the region of the plane of symmetry of the nutating movement of the disc. Each element contains mirror-symmetrical concavities defining one overall cavity within the casing and a nozzle may be provided as the entry means for working fluid in the parting plane of the two elements.

The nozzle itself can with advantage be constructed so that the cross-section of its orifice increases with rising pressure of the working fluid. Such an arrangement improves the efficiency of the vibrator by reducing the consumption of working fluid in the event of the vibration frequency being controlled by variations in the working pressure. This end is achieved by providing a nozzle mouthpiece which is elastically deformable by the working fluid. The inlet orifice can then be expanded when the pressure of the working fluid rises and the adjusted cross-section will provide an approximately constant velocity of flow of the working fluid.

By way of example, the accompanying drawings illustrate certain preferred embodiments of the invention. In the drawings:

FIG. 1 is a cross-sectional view of the vibrator taken on the line l-1 of FIG. 2

FIG. 2 is a plan view of the vibrator shown in FIG. 1

FIG. 3 is a cross-sectional view of an alternative disc having no central bearing means;

FIG. 4 is a detail cross-sectional view of the disc shown in FIG. 1

FIG. 5 is a cross-sectional view of another alternative disc provided with a central ball race bearing means FIG. 6 is a cross-sectional view of yet another alternative disc provided with a central ball bearing means FIG. 7 is a detail cross-sectional view showing the edge of a still further alternative disc having a chamfered edge and FIG. 8 is a detail cross-sectional view of an entry noz- 'zle for use in the vibrator shown in FIGS. 1 and 2.

FIGS. 1 and 2 show a vibrator which in practice may be about four inches in diameter. The vibrator includes a casing comprising two

casing members

1 and 2 which engage each other in a plane 9 and are held together by four set-screws 3.

Within the casing there is a cavity 4 defined by a concave spherical surface 8 and by inwardly projecting lower and upper coaxial

conical surfaces

5 and 6. The cavity 4 is symmetrical both about the plane 9 and about the axis of the

conical surfaces

5 and 6.

Within the cavity 4 there is a fitted an inertia disc 7 of substantially the same diameter as the spherical surface 8. The disc 7 is movable in rotation about its axis and is also tiltable into and out of alignment with the plane 9, this tilting being limited by the axially opposite faces of the disc making line contact with the generators of

conical surfaces

5 and 6 respectively.

Substantially in the plane 9 there is an inlet 10 for a working fluid. The inlet 10 is shaped to hold a nozzle such as is shown in FIG. 8 and to align the nozzle for directing the working fluid along a path substantially in the plane 9 and to one side of the axis of symmetry of the cavity 4. There is also an outlet for the working fluid, such outlet being comprised of a row of parallel channels 11 distributed along the line of intersection of the conical and

spherical surfaces

5 and 8 in the element 1. That the fluid outlet is a row of apertures eliminates the need for any filter means to prevent the ingress of dirt or other contaminant when the vibrator is not in use.

In the vibrator shown in FIG. I the disc will be maintained in an inclined position relative to the plane 9 by ball-ended rods 14 and 15. These ball-ended rods 14 and 15 engage, with their balLends l6and 17 respectively,

hemispherical recesses

18 and 19 centrally located in the opposite faces of the disc 7. The

recesses

18 and 19 are shown most clearly in FIG. 4. The rods themselves are received within coaxial conical recesses 12 and 13. in the apices'of the

conical surfaces

6 and 5. The nozzle shown in FIG. 8 comprises a body 29 having a screw-threaded portion 28 by which it can be screwed into the inlet 10 shown in FIG. 1. Forward of the screwthreaded portion 28 there is a connector 30 which may be provided with screw threads or be shaped to receive as a push fit over it a mouthpiece 31. The mouthpiece 31 is of elastically deformable material such as rubber or a synthetic plastic and comprises a converging passage 32 terminating in an orifice 33. The size of the orifice 33 depends on the flow rate of working fluid passing through the nozzle so that when the flow rate is increased, the orifice will expand accordingly. By using a nozzle of this kind, a jet of working fluid can be created within the cavity 4. It will be understood however, that the nozzle may also have other applications.

The operation of the vibrator will now be described. When a jet of working fluid is introduced into the cavity 4 through the mouthpiece 31 positioned within the inlet 10, it will impinge on one or other surface of the disc 7. In the position of the disc 7 shown in FIG. 1, the jet will impinge on the lower surface of the disc and will cause the periphery of the disc to roll upon the

conical surfaces

5 and 6 in a clockwise direction (FIG. 2) so that the axis of the disc will perform a nutating movement about the axis of symmetry of the cavity 4. It is this nutating movement of the disc 7 which causes the vibration of the vibrator. Although the disc 7 has been described as rolling on the

surfaces

5 and 6, the movement will actually be a combination of rolling and slid- Alternative forms of disc are shown in FIGS. 3, 5, 6, and 7, the simplest form of disc being shown in FIG. 3. The disc 7 shown in FIG. 3 has no

central recesses

18 and 19 and is provided simply with parallel opposite surfaces.

The disc 7 shown in FIG. 5 is provided with ball hearing means 21 by which it is mounted on a shaft 20 supported coaxially with the axis of symmetry of the cavity 4. The ball bearing means permits the disc 7 to move as described with particular reference to FIG. 1 and also maintainsthe disc accurately centered upon the axis of symmetry of the cavity 4.

FIG. 6 shows an alternative bearing means for the disc 7 comprising a central ball 23 supported within the cavity 4 on the axis of symmetry thereof. The ball 23 is received within

recesses

24 and 25 in the apices of the

conical surfaces

5 and 6 and the disc 7 is provided with an opening 22 within which the ball 23 is received.

It may happen that there is difficulty in starting the vibrator where the disc 7 is of the kind shown in FIGS. 3, 5 and 6. This difficulty can arise where the disc is started from an at-rest condition aligned with the plane 9 or otherwise obstructing the inlet 10. The disc shown in FIG. 7 can overcome this difficulty by having its periphery chamfered at 26 to a circular line edge and in association with this the inlet 10 has a channel 27 extending into the element 2. In the position of the disc 7 shown in FIG. 7, working fluid jetted into the cavity 4 through the inlet 10 .will be deflected by the disc 7 both upwardly and downwardly, but in view of the channel 27, more fluid will be deflected upwardly than downwardly, and this in turn will cause the disc 7 to tilt out of alignment with the plane 9 and to commence its nutating movement.

It will be appreciated that the description of the present embodiments of the invention are given for the purpose of illustration only and that the invention can be embodied in other forms within the spirit and scope of the appended claims.

I claim:

1. A vibrator comprising a casing, a cavity within the casing, nutating inertia disc means in the cavity guided by cooperating surfaces of the cavity, [and] inlet means and outlet means for conducting a working fluid into and out from the cavity wherein said inlet means is positioned in a wall of the casing to direct the working fluid into the cavity along a path lying substantially in the plane of symmetry of the nutating movement of said disc means, whereby working fluid directed into the casing by the inlet means will impinge upon the disc means to cause nutating movement thereof, the inlet means and the outlet means further being arranged to conduct the working fluid exclusively through stationary parts of said casing, and a supporting element guided 'in said casing and connected with said disc means on at least one side thereof.

2. A vibrator as claimed in claim wherein said '56 operating surfaces define said cavity and are so shaped that the outer periphery of said disc means is in subs satiaLtql iassnsss asstw i. Surfaces- 3. A vibrator as claimed in c laim f wherein said supporting element comprises bearing means mounted in said casing.

4. A vibrator as claimed in claim 1 wherein said cooperating surfaces include two inwardly projecting conical portions, said conical portions being disposed each on axially opposite sides of said disc means, each said conical portion being a coaxial mirror image of the other and each said conical portion carrying at its apex a respective supporting element for said disc means, said disc means being tiltable out of said plane of symmetry to a maximum inclination wherein axially opposite faces thereof make line contact each with a respective generator of a respective one of said conical portions.

5. A vibrator as claimed in claim 4 wherein each said supporting element is a ball-ended rod comprising a rod portion carrying a ball at one end, said balls being received each in a respective socket in a respective one of said axially opposite faces of said disc means and said rod portions being received each within a respective conical recess in the apex of a respective one of said conical portions, and bearing against the inside surface of said conical recess.

6. A vibrator as claimed in claim 4 wherein said disc means includes at its centre a mounting ball having parts thereof exposed on axially opposite sides of the disc means, said exposed parts being received in complementary sockets which comprise the supporting elements in the apices of said conical portions to provide a bearing for the disc means.

7. A vibrator as claimed in claim GWhCfElfl said mounting ball is movably received at the centre of the disc means.

8. A vibrator claimed in claim 7 wherein the mounting ball is'less than one tenth of the diameter of the disc means.

9. A vibrator as claimed in claim 4 wherein said supporting elements are the end parts of a shaft carried by the apices of said conical portions, said shaft passes through the disc means, and carries the disc on ball bearing means.

10. A vibrator as claimed in claim 1 wherein the out let means comprises a plurality of channels connected in parallel.

11. A vibrator as claimed in claim 1 wherein the axially opposite faces of the disc means are flat.

12. A vibrator as claimed in claim 1 wherein the axially oppositc faces of the disc means are conical and are mirror images one of the other, said disc means being progressively thickened towards its periphery.

13. A vibrator as claimed in claim 1 wherein said casing comprises two elements which contain mirror symmetrical concavities and said entry means is positioned in the region of the parting plane of the two parts.

14. A vibrator as claimed in claim 1 wherein said inlet means includes a nozzle the cross-section of which increases with increase in the flow rate of working fluid therethrough. i

15. A vibrator as claimed in claim 14 wherein the working fluid is a compressed gas.

16. A vibrator as claimed in claim 15 wherein the working fluid is compressed air.

17. A vibrator as claimed in claim 16 wherein said inlet means includes a channel for working fluid leading out of said plane of symmetry to one side thereof.

18. A vibrator as claimed in claim 14 wherein said nozzle includes a mouthpiece of elastically deformable material which is deformable by the working fluid.

19. A vibrator claimed in claim 1 wherein the periphery of said disc is chamfered to a circular line edge.

Claims

1. A vibrator comprising a casing, a cavity within the casing, nutating inertia disc means in the cavity guided by cooperating surfaces of the cavity, inlet means and outlet means for conducting a working fluid into and out from the cavity wherein said inlet means is positioned in a wall of the casing to direct the working fluid into the cavity along a path lying substantially in the plane of symmetry of the nutating movement of said disc means, whereby working fluid directed into the casing by the inlet means will impinge upon the disc means to cause nutating movement thereof, the inlet means and the outlet means further being arranged to conduct the working fluid exclusively through stationary parts of said casing, and a supporting element guided in said casing and connected with said disc means on at least one side thereof.

2. A vibrator as claimed in claim 1 wherein said cooperating surfaces define said cavity and are so shaped that the outer periphery of said disc means is in substantial rolling engagement with said surfaces.

3. A vibrator as claimed in claim 1 wherein said supporting element comprises bearing means mounted in said casing.

7. A vibrator as claimed in claim 6 wherein said mounting ball is movably received at the centre of the disc means.

8. A vibrator as claimed in claim 7 wherein the mounting ball is less than one tenth of the diameter of the disc means.

10. A vibrator as claimed in claim 1 wherein the outlet means comprises a plurality of channels connected in parallel.

12. A vibrator as claimed in claim 1 wherein the axially opposite faces of the disc means are conical and are mirror images one of the other, said disc means being progressively thickened towards its periphery.

14. A vibrator as claimed in claim 1 wherein said inlet means includes a nozzle the cross-section of which increases with increase in the flow rate of working fluid therethrough.

19. A vibrator as claimed in claim 1 wherein the periphery of said disc is chamfered to a circular line edge.