US3808793A

US3808793A - Rocking pendulum

Info

Publication number: US3808793A
Application number: US00241540A
Authority: US
Inventors: R Ebdon
Original assignee: PERRY Ltd E
Current assignee: PERRY E Ltd GB; PERRY Ltd E
Priority date: 1971-04-13
Filing date: 1972-04-06
Publication date: 1974-05-07
Anticipated expiration: 1991-05-07
Also published as: FR2132867A1; AU461958B2; DE2217881A1; IT950965B; GB1390504A; FR2132867B1; JPS5316701B1; AU4072372A

Abstract

A device capable of providing audible oscillatory movement of a body about a position of stable equilibrium is disclosed. The body normally rests on two edges, but when displaced therefrom will oscillate about the position making an audible ''''click'''' as it steps from one edge to the other.

Description

Unlted States Patent 1 91 1111 3,808,793 Ebdon 5] May 7, 1974 ROCKING PENDULUM 449,635 3/1891 P11110111 58/130 R 563,618 7/1896 Rhodes 58/129 [75] Inventor- Ebdm" 605W", 1,548,738 8/1925 Pappas 58/130 A England 1,191,285 7/1916 Cushing..... 58/130 R 4 2,138,345 11/1938 .lunghans 58/129 [73] Asslgnee' 33 Gosport 3,360,920 1/1968 Heim 58/2 [22] Filed: 1972 Primary ExaminerStephen J. Tomsky [21] Appl. No.: 241,540 Assistant Examiner-Vit W. Miska Attorney, Agent, or Firm-Molinare, Allegretti, Newitt [30] Foreign Application Priority Data & wltcoff Apr. 13, 1971 Great Britain 9238/71 52 US. 131 58/130 R, 58/130 A, 58/129, '[57] ABSTRACT 51 I t A device capable of providing audible oscillatory i 130 A movement of a body about a position of stable equilible 0 earc 58/29. 2 rium is disclosed. The body normally rests on two edges, but when displaced therefrom will oscillate about the position making an audible click as it [56] uNlTE g gg zg E s giiENTssteps from one edge to the other.

527,233 10/1894 Bartel 58/129 ll Claims, 5 Drawing Figures ROCKING PENDULUM This invention relates to devices for'producing audible oscillatory movement of a body. Such devices are simple in principle and capable of easy understanding. They could for example, oscillate for a predetermined length of time and thus find application in teaching children about the concept of time.

The principle of the invention is the production of an oscillatory motion, the smoothness of which is interrupted by a break therein, defined by two edges which are on either side of the line of action of the weight of the device which is in a position of stable equilibrium, thereby causing an audible click as the device reaches its equilibrium position. It is a condition of the invention that the device is in stable equilibrium when it is at rest on the two edges.

The present invention provides a device for providing audible oscillatory movement of a body about a position of stable equilibrium, comprising a body having thereon two edges which, when the body is supported on them, definethe position of stable equilibrium, the devices including means to bias the body toward the position of stable equilibrium when the body is displaced therefrom and including means defining such a displacement of a predetermined amount.

Conveniently the means biasing the body towards the position of stable equilibrium takes the form of one or more weight which weight or weights, when the body is displaced from the position of stable equilibrium, exert a moment on the body to bias the body toward the equilibrium position.

The edges would normally be substantially parallel. Their orintation can in any case be such that the oscillations of the body continue for a period of time which, for a given orintation of the edges, is dependant on the means for biasing the body towardthe position of stable equilibrium.

In one embodiment of the invention the device may comprise a body having an arcuate effective surface upon which the body may roll broken by the two edges, two linear surfaces tangential with the arcuate surface and extending'from points thereon symmetric about the edges, which linear surfaces define the predetermined displacement. It is often desirable that the linear surfaces converge at a point on a line extending from a position midway between the edges through the centre of curvature of the arcuate surface. The arcuate effective surface can conveniently be cylindrical.

The term effective surface is used to include an imaginary surface which would be defined between two parallel rails. In a particular form of the embodiment of the invention just described the effective surface comprises two similar spaced, parallel, discontinuous rails, the discontinuities of which define the edges.

Thus a device in accordance with the invention may take the form of a weighted roller or pear-shape with a gap cut in the rolling surface.

Another embodiment of the invention can comprise a pendulum suspended on two edges, a weight being movably attached to the pendulum remote from the point of suspension and including a releaseable catch to hold the remote end of the pendulum at the predetermined displacement. The pendulum may have at its point of suspension two knife edges directed towards its opposite sides which can rest on a discontinuous surface of the device which discontinuity allows the arm of the pendulum to pass therethrough. Alternatively the pendulum may have at its point of suspension a planar surface directed towards the remote end and which can rest on two knife edges fixed in the device.

A device according to the invention may be so weighted that if released from a position where the diaplacement from equilibrium is a known value, it would oscillate for a fixed period of time, the end of which would be clearly defined by a final audible click.

By altering the dimensions and weight characteristics of an embodiment of the invention then the length of time which may be measured can be altered.

The invention will be better understood by considering the following examples and referring therefrom, to

the accompanying drawings, wherein:

FIG. 1 is a perspective view of an embodiment of the invention;

FIG. 2 is a plan view of the embodiment of FIG. 1;

FIG. 3 is a perspective view of another embodiment of the invention;

' FIG. 4 is an end view of the embodiment of FIG. 3; and

FIG. 5 is a detail view of the fulcrum mechanism of FIG. 3.

EXAMPLE I The embodiment shown in FIG. 1 is substantially in the form of a flat plate having the outline shape of a segment of a circle, greater than a semicircle, from the ends of which are drawn tangents 2 to the circle to meet at apex 3. Along the periphery of the segment there is attached a flange 6 including runners 1. The runners l are cut away at the base of the unit to form two edges 5. The unit is so weighted that the unit is in a state of stableequilibrium when resting with the line of symmetry vertical on its fulcrums on edges 5 as the only supports. Further the weight 4 is so positioned to produce a restoring couple when the unit is displaced from its equilibrium position.

When the unit is displaced from its equilibrium position and then released it will perform oscillatory ,motion by rolling on the runners 1. As the unit reaches the equilibrium position the unit steps from one edge to the other, thus producing a sound similar to the tick of a clock. When the unit is in motion there will be two ticks per cycle, and when it comes to rest there .will be a distinct cut-off to the motion defined by a final tick.

When the apex .3 is held down .to a horizontal surface, upon which the unit is to oscillate, such 'that the tangent 2 is substantially in contact with the surface :along the length of the tangent, and then released, :the 'unit .will oscillate for a fixed length of time and this :time :may be regarded as a constant, and :used as such.

By altering the dimensions of the :Ul'lili, the spacing of the fulcrums 5, and the position .of the weight 4 the fixed length of time for oscillation may be altered.

EXAMPLE 2.

The embodiment shown in FIG. .3 is in "the .formof a pendulum which swings on .a two edged fulcrum. The

pendulum consists of anarm .12 and a wcight 1 4 which may be .held in a number of positions thereon, :thus .al-

3 pendulum is in a state of stable equilibrium when the flat surfaces 16 is horizontal, the two edges of the fulcrum are resting thereupon and the arm 12 is vertical. 1

The two flat surfaces 16 are formed on an inverted, generally U-shaped (in transverse vertical crosssection) member16A as best shown in FIG. 4. The upper end of the arm 12 is disposed between the depending portions of the member 16A, and the lower end of the arm 12 is disposed within a guide slot 17 formed in a base 18. The upper end of a vertical stand 19 supports the member 16A while the lower end of the stand 19 is supported by the base 18.

When the pendulum is displaced from the equilibrium position and then released it will perform oscillatory motion which will be audible by virtue of the fulcrum arrangement. This sound will simulate the ticking of a clock in the same way as described in Example 1. Thus there will be two ticks per cycle and a distinct cutoff when the motion is completed defined by a final tick.

In this embodiment of the invention there is a catch 13 fixed in the base 18 of the embodiment, designed to mate with a hook or the like on the end of the arm 12. This catch defines the initial displacement of the pendulum and thereby fixes the time for motion of the pendulum for a given position of the weight on the arm.

The magnitude of the weight and its position on the arm may be varied thereby allowing, theoretically, infinite variation in the lengths of time for oscillation.

For a given weight, the arm associated with the weight may be calibrated.

What we claim is:

1. An improved device adapted to make a regular audible sound when oscillatorily moved on a support surface, about a position of stable equilibrium comprising: a body having defined thereon two, co-planar, spaced apart edges, with the edges being spaced from and positioned on either side of a vertical plane including the center of gravity of the body and being adapted .to contact a support surface; the body being capable of oscillatory movement on the support surface, and about a position of stable equilibrium, upon the displacement of the body from its position of stable equilibrium so that during said oscillatory movement, only one or the other of said edges is in contact with the support surface; and means for biasing the body toward its position of stable equilibrium from a predetermined displacement so that the body will oscillate from one edge to the other edge until it resumes its position of stable equilibrium.

2. A device according to claim 1 wherein the means biasing the body toward the position of stable equilibrium comprise at least one weight which weight or weights, when the body is displaced from the position of stable equilibrium, exert a moment on-the body to bias the body toward the equilibrium.

3. A device according to claim 1 wherein the edges are a predetermined distance apart and wherein the means biasing the body toward the position of stable equilibrium are such that the body oscillatesfor a fixed period of time when released from the predetermined displacement.

4. A device according to claim 1 wherein the edges are. substantially parallel.

5. A device according to claim 1 comprisinga body having an arcuate effective surface upon which the body may roll broken by the two edges, two linear surface tangential with the arcuate surface and extending from points thereon symmetric about theedges, which linear surfaces define the predetermined displacement.

6. A device according to claim 5 whereinthe linear surface converge at a point, which point is on a line extending from a position midway between the edges through thecentre of curvature of the arcuate surface.

7. A device according'to claim 6 wherein the arcuate I attached to the pendulum remote from the point of suspension; and wherein the device includes a releaseable catch to hold the remote end of the pendulum arm at the predetermined displacement.

' 10. A device according to claim 9 wherein the pendulum has as its point of edgesuspension two knife edges directed towards opposite sides of the pendulum resting on the support surface, said support surface comprising a discontinuous surface in the device; and

wherein the arm of the pendulum passes through the discontinuity.

' 11. A device according to claim 9 wherein the pendulum has at its point of edge suspension a planar surface directed towards the remote end of the pendulum adapted to rest on the two edges comprising knife edges fixed in the device.

Claims

1. An improved device adapted to make a regular audible sound when oscillatorily moved on a support surface, about a position of stable equilibrium comprising: a body having defined thereon two, co-planar, spaced apart edges, with the edges being spaced from and positioned on either side of a vertical plane including the center of gravity of the body and being adapted to contact a support surface; the body being capable of oscillatory movement on the support surface, and about a position of stable equilibrium, upon the displacement of the body from its position of stable equilibrium so that during said oscillatory movement, only one or the other of said edges is in contact with the support surface; and means for biasing the body toward its position of stable equilibrium from a predetermined displacement so that the body will oscillate from one edge to the other edge until it resumes its position of stable equilibrium.

2. A device according to claim 1 wherein the means biasing the body toward the position of stable equilibrium comprise at least one weight which weight or weights, when the body is displaced from the position of stable equilibrium, exert a moment on the body to bias the body toward the equilibrium.

3. A device according to claim 1 wherein the edges are a predetermined distance apart and wherein the means biasing the body toward the position of stable equilibrium are such that the body oscillates for a fixed period of time when released from the predetermined displacement.

4. A device according to claim 1 wherein the edges are substantially parallel.

5. A device according to claim 1 comprising a body having an arcuate effective surface upon which the body may roll broken by the two edges, two linear surface tangential with the arcuate surface and extending from points thereon symmetric about the edges, which linear surfaces define the predetermined displacement.

6. A device according to claim 5 wherein the linear surface converge at a point, which point is on a line extending from a position midway between the edges through the centre of curvature of the arcuate surface.

7. A device according to claim 6 wherein the arcuate effective surface is cylindrical.

8. A device according to claim 7 wherein the arcuate effective surface comprises two similar spaced, parallel, discontinuous rails, the discontinities of which define the edges.

9. A device according to claim 1 wherein the body comprises a pendulum arm suspended on the two edges wherein the biasing means includes a weight moveably attached to the pendulum remote from the point of suspension; and wherein the device includes a releaseable catch to hold the remote end of the pendulum arm at the predetermined displacement.

10. A device according to claim 9 wherein the pendulum has as its point of edge suspension two knife edges directed towards opposite sIdes of the pendulum resting on the support surface, said support surface comprising a discontinuous surface in the device; and wherein the arm of the pendulum passes through the discontinuity.

11. A device according to claim 9 wherein the pendulum has at its point of edge suspension a planar surface directed towards the remote end of the pendulum adapted to rest on the two edges comprising knife edges fixed in the device.