US3040446A - Wave generating mechanism - Google Patents

Description

June 1962 J. H. ELLINGER 3,04

WAVE GENERATING MECHANISM Filed April 22, 1960 3 Sheets-Sheet 1 FIG. I.

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FIG. 3

JOHN HENRY ELLINGER INVENTOR June 26, 1962 J. H. ELLINGER WAVE GENERATING MECHANISM 3 Sheets-Sheet 2 Filed April 22, 1960 JOHN HENRY ELLINGER INVENTOR June 26, 1962 J. H. ELLINGER WAVE GENERATING MECHANISM 3 Sheets-Sheet 3 Filed April 22, 1960 JOHN HENRY ELLINGER FIG.|I

INVENTOR f United StatcsPatent Ofiice 3,040,446 Patented June 26, 1962 3,040,446 WAVE GENERATING MECHANISM John Henry Ellinger, Parirstone, Peale, Dorset, England,

assignor to Minister of Works, in Her Majestys Goveminent of the United Kingdom of Great Britain and Northern Ireland, London, England Filed Apr. 22, 1964 Ser. No. 24,115

r 9 Claims. (CI. 35-19) and permitting the following adjustment:

(1) Phase angle between successive displacers (set individually).

(2) Eccentricity common to or variable between all paddles (set individually or in groups).

(3) Angular velocity common to all trolled by the shaft speed).

(4) True sinusoidalmotion for. all paddles.

Since there may be several hundred displacers in a wave-generator the making of some adjustments, for ex-;

ample 1, 2' or 4 (above), would frequently necessitate individual adjustment of the cam or the equivalent thereof appertaining to each displacer.

An object of the present invention is to provide a wavemaking mechanism in which the number of parts for obtaining adjustments such as those previously mentioned is reduced to a minimum, thereby not only considerably reducing the cost of the machine, but also the number of operations and therefore the time involved in making these adjustments.

A wave making machine according to the present inventionv comprises a number of oscillatable fluid-displacers, a plurality of mechanical bus-bars, adjustable transmission means for individually imparting a I presettable extent of oscillatory movement to each of the said bus-bars, and a motion pick-off device for each fluid displacer, whereby motion may be picked-01f any one of the said bus-bars to drive this displacer. i

Preferably the machine is also provided with phase varying means for varying the operating phase relationship between displacers.

The bars or strips which may be arranged to extend along and in spaced relationship to a row orgroup of displacers and the means through which the latter may be operated from the bars may include motion transmission or conversion means interposedbetween individual displacers and bars and capable of being selectively rendered operative between any displacer and any bar. Each strip or bar may, for example, be given a reciprocating movement transversely of its length in a horizontal plane, and the means interposed between the bars andrespective displacers may each comprise a link coupled or joined to each displacer, but arranged so that all the bars pass through it with suflicient lateral clearance to permit free reciprocation of said bars without moving the said link. Associated with each link isn'ieans for selectively eliminating or reducing the clearance between the link and any particular bar passing therethrough, so'v that the said bar will then operate the displacer through this link. l

Instead of the arrangement being such that the bars I may be operatively connectedto the'displacers by links paddles (con- 2 a such as just described, levers may be employed through or between portions of which the bars pass, suitable lost motiontake-up or other means being provided whereby operation of preselected displacers'by any'particular bar or'bars can be effected.

instead of the arrangement being such that the bars are reciprocated transversely of their length they may be arranged to have a reciprocatory rotary motion about their axes or an axial reciprocation and each carry= -a cam within or adjacent each link or lever, anyone of which cams may be selectively clamped or clutched to its particular bar in respect of each link or lever to operate same and consequently its individual displacer. In the case of links being used in this construction it would, of course, be necessary for them to be mounted in guides.

Reference will now be had to the accompanying drawings, of which: FIGS. 1, 2 and 3 are views, showing diagrammatically, differences in amplitude and frequency of generated waves,

FIG. 4 is a diagrammatic view of one example of 'a paddle type of wave-making machine according 'to the j invention,

s-A 'sA of FIG. 5C is a sectional view taken on line 5C5C of FIG. 5,

FIGS. 6 and 7 are diagrammatic views showing ,a

' modification of a portion of the structure shown in FIG. 4,

FIG. 8 is a diagrammatic view of a further example of Wave making machine according to the invention,

FIG. 9. is a sectional view on line 9--9 of FIG. 8 showingpart of the paddle operating-means shown in FIG. 8,

FIG. 10 is a sectional view on line 10 of FIG. 8, of a detail; and 7 FIG. 11 is a perspective view of a further detail.

Referring to the drawings, FIG. 1 shows a wave of one frequency and amplitude, FIG. 2a wave of lesser frequency and amplitude, and FIG. 3 a further wave of a' frequency and amplitude lying somewhere. between those of the waves shown in FIGS. 1 and 2.

It is pointed out that if all the paddles of a wave making machine are moved to and fro in unison, waves will be propagated in a direction normal to the wave making machine. v v

It is pointed out that by moving groups of paddles in one order of sequence, the waves generated will travel obliquely from the apparatus in one direction, but if the operation is effected in the reverse sequence then waves will be developed which travel obliquely in the reverse direction. 7

- In the embodiment of the invention shown in FIG. 4, vertical paddles 1 are anchored at their lower ends to the'bottom of a tank 2 by spring ilexures 3. These paddle units areof identical construction and each has fixed to its rear face, at a pointnear its upper end, the forward end of a horizontal link 4, which is of rectangular: crosssection and is provided with a group of rectangular slots 5 a (FIG, 4) which extend through it from side to side.

Passing through the slots 5 of the links 4 are a number of strips 6 each of which is'provided near each of its ends acrea e scribed. It should here be explained that, whereas in FIG. 4 four superimposed strips 6 are shown, FIG. shows only two such strips each of which has its rearwardly directed elements such as 7, each associated with a ring 8 and eccentric.9 having a pin 10 engaging with a track 11 of a cam 12, it should, nevertheless, be understood that in the embodiment shown in FIG. 4 for each strip 6 there is an element 7, a ring 8, and an eccentric 9, each eccentric carrying a pin 10 engaging with a spiral 11 in its own cam 12.

Each of the cams 12 and its associated eccentric 9 is contained beneath respective discs 13 and 13a, formed integral with the upper end of a downwardly extending hub 14 the lower end of which is formed integral with a disc 15 which revolubly fits into a recess 16 formed in the upper surface of a further disc 13a formed at the upper end of a further hub 14a at the lower end of which is formed integral a further disc 15a, and so on. The lowermost disc 15a revolubly fits into a recess 16a formed 'in a bottom disc 1311, which is not provided with a hub,

14a. The whole assembly just described is rotatably mounted upon a vertical spindle 17 carried at its lower end in a bracket 18, the said spindle being screw-threaded at its upper end and carrying thereat a retaining nut 19. It will, of course, be understood that although this method of mounting the cam assemblies is not shown in FIG. 4, this is merely because that view is diagrammatic.

The portion of each of the hubs 14 which is surrounded by the associated eccentric 9 is provided wtih diametrically opposite flats (not shown), which form guides for the eccentric, which is providedwith an appropriately elongated slot 20 with which these flats cooperate to constrain the movement of the eccentric, relative to the hub 14 to a purely rectilinear motion when either of the cams 12 is rotated relative to the hub 14 and a cooperating eccentric 9, all in the manner set forth in the following paragraph.

'Each of the cams 12 has gear teeth 21 formed around its outer edge, with which engages a pinion 22 mounted on a pin 23 screwed into the underside of the discs 13 and 13a. Rotation of each pinion 22 will in turn rotate the associated cam 12 to cause the spiral track 11 thereof to act upon the pin 10 of the associated eccentric 9 and adjust the degree of eccentricity of this eccentric with re- ,spect to the axis of the spindle 17. Each of the pinions 22 may have attached to it a thumb-wheel (not shown) to facilitate its being rotated, and this thumb-wheel would preferably be engraved to afiord an indication of the degree of eccentricity to which the associated eccentric 9 is set. Suitable means, such as spring washers 22a for example, would be provided upon the pins 23, and between the pinions 22 and the discs 13 and 13a respectively, to prevent rotation of the pinions 22 relative to the earns 12 upon rotation of the entire mechanism, including of course the discs 13 and 13a.

The underside of the peripheral portion of the lowermost disc 13b is provided with bevel gear teeth 24 with which engages a bevel gear 25 carried on a horizontal shaft 26 journaled in bearings 27 formed at the outer ends of lugs such as 28 formed upon the brackets 18. It will be obvious from the foregoing description that the shaft 26 extends through the bearings 27 formed in the lugs 28 of successive brackets 18, although these brackets have been omitted from FIG. 4.

Coupled to the shaft 26 is a motor 29 (FIG. 4) by which this shaft may be rotated.

Each of the discs 15, 15a is secured against rotation within the recess 16 of the underlying disc 13, 13b by a pin 30 which constitutes part of an arrangement which will hereinafter be further described. Rotation of the shaft 26 will therefore rotate not only the lowermost disc 13b of the disc assemblies at the ends of the strips 6, but all the superposed discs 15, Hand 13; 13a of each of these assemblies. It is emphasized that by virtue of the presence of the frictional washer 22a between the respective pinions 22 and the discs 13 and 13a, the respective pinions 22 are normally restrained against rotation relative to said discs 13 and 13a. Hence elements 14, 13, 23, 22, 12 and 9 are caused to rotate together as what amounts to a single unit, without relative motion therebetween; more specifically all of these elements rotate at the same number of revolutions per minute. It will, of course, be understood that the eccentrics associated with the opposite ends of each strip 6 would be previously adjusted to give an equal throw and to operate in unison.

In FIG. 11 is shown a substantially U-shaped key 31, which is adapted to be pushed into any one of the slots 5, with its limbs against the opposite edges of the strip 6 passing through this slot, so as to lock this strip to the link 4. A number of the keys 31 are provided. The

outer ends of the parallel limbs of each key 31 are tapered to facilitate entry into each slot 5, these limbs also being so shaped or set that they will spring slightly toward each other upon entering the slot in order that the key will not slide out of the slot during operation of the mechanism.

I to it through its respective link 4, upon insertion of one ,of the keys 31 into the appropriate slot 5.

Moreover,

. displacement between paddles connected to different busbars may be effected by adjustment of the cams 12 operatively associated with these bus-bars.

In order to obtain a predetermined degree of phase displacement between two adjacent strips 6, each of the discs 15, 15a is provided with a number of blind ended holes such as 32 for receiving the pin 30, and each of the discs 13 and 13b is also provided with a number of similar holes such as 32a, each of which may successively be brought into register with one of the holes 32 in the adjacent discs 15, 15a and the said pin placed so as to protrude into both these holes. A large number of angular settings between each disc 13a, 13b and its adjacent disc 15, 15a may be obtained in this manner, after first removing the nut 19 upon the spindle 17, to enable the disc 15' to be lifted off the disc 13a.

In cases where it is necessary to employ a number of groups of paddles such as necessitates a multiplication of the number of pairs of cam assemblies, provision would be made for altering or adjusting the phase relationship between these groups and for this purpose each bevel gear 25 is fixed relatively to the shaft 26 by a screw 50 which passes through one or other of a number of holes 25a drilled through it from face to face and screwed into one or other of a number of holes 52 in a disc 54 which is keyed to said shaft, the arrangement being such that any particular hole 25a of each bevel gear 25 of a pair of these bevel gears operating the cam assemblies associated with a particular strip 6 may be brought into register with any particular hole of the adjacent disc, and the said screw passed through the pairs of holes which have been selectively brought into register.

In FIGS. 6 and 17 is shown an alternative method of construction in which, instead of the links 4 being directly affixed at their forward ends to the paddles 1, they are connected thereto by flexible and springy linnks 33 pivoted at their opposite ends between said links 4 and the paddles 1, the spring flexures 3 being replaced by flexible barlike extensions 1a so anchored to the bottom of the tank 2 that their connection thereto may be slackened to permit both them and their associated paddles to be twisted about their vertical axes so as to lie, in a transverse sense, substantially parallel to the line of configuration of the adjacent part of any particular Wave front, to be produced, the said spring flexures then being refixed to the bottom of the tank in these adjusted positions. The flexible and springy nature of the links 33 will not.

only permit of this adjustment by flexing or bowing, but.

will likewise .permit of the operation of paddles in such adjusted positions.

In themodified construction shown diagrammatically in FIG. 8, a plurality of the actuating cam assemblies are mounted directly upon the shaft 26 which, in this case, is arranged above the strips 6 and with its axis parallel thereto. Only a few of these cam assemblies are shown in this figure. In accordance with this embodiment in each cam assembly, each cam 12 is arranged to adjust the extent of eccentricity of two eccentrics 9 and 9, as shown in FIG. 9. Each follower ring; 8 is provided with a radial lug 34 andv the arrangement being such that the lugs 34 of each adjacent pair of rings 8 extend outwardly in diametrically opposite directions. As shown in the assembly illustrated in FIG. 8, each lug 34 is pivoted at its outer end to the upper end of a lever 35 arranged to fulcrum about a point x on a support 35a (only one shown). The lower end of each lever 35 is pivoted to the outer. end of a bar 36 which is welded or otherwise suitably aflixed to one of the strips 6. It would, of course, be necessary for there to be a certain amount of vertical play in the pivots at the opposite ends of the levers 35.

Upon reference to FIG. 9, which shows a single cam unit or assembly, it will be seen that each or a number of discs 13' and 13 is provided with a lug 1 3a having a screw-threaded perforation 37 into which is screwed a headed pin 38 (as shown in FIG. 9 only with respect to the lower .disc 13"), whichpin carries a gear wheel 39 which meshes'with teeth 4t? formed around the edge of a plate 15'. A disc 41, which constitutes a washer, is interposed between the plate 15, and the adjacent plate 13". Although, in FIG. 8, there is shown only a few units each as shown in FIG. 12, there would, of course, be a number of such cam units arranged in groups at spaced positions along the shaft 26. By rotating the gear wheel 39 a unit upon the pin 38, thedisc 15 can be rotated with respect to the adjacent disc 13 to change the operating phase angle between one of the said units and an adjacent unit.

As will be seen upon reference to FIGS. 8 and 9, the disc 13 of each cam unit is provided with a boss 13"b pinned to the shaft 26 by a tapered pin 42. Each of i gear wheel 39 and the associated disc 135, the purpose of these washers being to prevent rotation of the respective gear wheels during operation of the mechanism.

The levers 35 which, as previously stated, are connected at their upper ends to the lugs 34 of each air of ad jacent rings 8, will be operated at 180 out of phase with each other. This will be clearly appreciated upon reference to FIG. 9. It will also be underestoodthat the shaft 26, which extends along in a direction parallel to the groups of strips 6, is provided at both of its ends with a similar cam assembly to that just described, the corresponding eccentrics 9 of which are set to work in unison. g

It is evident that when very long wave lengths are to be utilised parallel to the line of paddles, the movement between adjacent paddles will be extremely small. Under these conditions adjacent paddles may be linked by a thin sheet of rubber. 'In this case only each second or third'paddle would be operated and the others would be left free so that their inertia would cause them to assume the lag required to assist in providing the approximate profile of the wave.

Although in the foregoing description, specific examples of apparatus according to the invention have been described, it will be readily appreciated that various other embodiments of the invention are possible. For ex ample, in the case of the construction shown in FIG- URE 4, the driving shaft 26 may be replaced by a number of hydraulic motors, one for each cam assembly, suitable provision being made for eifecting any desired phase relationship between the pairs of motors operating the cam assemblies associated with the diiferent strips 6. This wouldpresent the advantage that it would eliminate any phase errors produced as a result of torsional strain such as might be encountered by the use of shafting.

The application of this invention to a paddle type wavegenerator, consisting, for example, of a large number of elements the individual lengthof which may be very small in relation to the length of the wave that can be produced, permits orientation of the generated waves to be obtained solely by employing a suitable time lag method in the operation of such elements. In this way it is possible, without changing the position of the apparatus, to generate waves of rectilinear front having the desired direction of propagation, as well as waves having a curvilinear front. This also renders it possible, in some cases, to reduce the scale of models of coastline or river bank locations, for example, because it is no longer necessary to simulate the contour of the sea or river bed to a distance from the shore where refraction tails 011 to zero.

Another advantage is that, in thecase of models of tidal basins, the apparatus can be placed permanently along any boundary of the model basin, a good boundary being one which would, for example correspond to the most natural stream line. Accordingly, the problem of tidal waves traversing the wave generator no longer arises, this being irrespective of the direction of such waves. It is also to be noted, moreover, that this apparatus renders possible the generation of waves the amplitude of which can be varied arbitrarily along the crest line.

I claim: a

1. A wave making machine comprising a number of oscillatable fluid-displacers, a plurality of mechanical busbars, adjustable transmission means for individually imparting a pre-setta'ble extent of oscillatory movement to each of the said bus-bars, and a motion pick-off device for each fluid displacer, whereby motion may be pickedofi" any one of the said bus-bars to drive this displacer.

2. A wave making machine comprising a number of oscillatable fluid-displacers, a plurality of mechanical busbars, adjustable transmission means for individually imparting a pre-settable extent of oscillatory movement to each of the said bus-bars, a motion pick-elf device for each fluid displaced, whereby motion may be picked-oil any one of the said bus-bars to drive this displacer, and phase varying means for varying the operating phase relationship between displacers.

3. A wave-making machine comprising a row of oscillatable fluiddisplacers, a plurality of bars extending substantially parallel with the row of displacers, adjustable transmission means for individually imparting a presettable extent of reciprocatory motion to each bar, a motion pick-off device appropriate to each fluid displacer,

which pick-off device is adapted to pick-off reciprocatory motion from any one of the bars to drive the displacer.

4. A wave-making machine as claimed in claim 3, comprising phase varying means for varying the operating phase relationship between displacers.

5. A wave-making machine comprising a row of oscillatory fluid-displacers, a plurality of bars extending substantially parallel with the row of displacers, adjustable transmission means for individually imparting a pre-settable extent of reciprocatory motion to each bar, which transmission means comprises variable throw cams, the machine also comprising a motion pick-01f device appropriate to each displacer for picking-off reciprocatory mo tion from any one of the bars to drive the displacer.

6. A wave-making machine comprising a row of oscillatory fluid-displacers, a plurality of bars extending substantially parallel with the row of displacers, adjustable transmission means for individually imparting a pre-settable extent of reciprocatory motion to each bar, which transmission means comprises variable throw cams, the machine also comprising a motion pick-off device appropriate to each displacer for picking-off reciprocatory motion from any one of the bars to drive the displacer, and phase varying means for varying the operating phase relationship between displacers.

7. A wave-making machine comprising a row of oscillatable fluid-displacers, a plurality of bars extending substantially parallel with the row of displacers, independent adjustable transmission means for individually imparting a pre-settable extent of reciprocatory motion to each bar, a lost-motion link between each displacer and all of the said bars, and means for selectively removing the lost motion between this link and any particular bar so as operatively to connect this to the displacer.

8. A wave-making machine comprising a row of oscillatable displacers, a plurality of bars extending substantially parallel with the row of displacers, independent adjustable transmission means for individually imparting a pre-settable extent of reciprocatory motion to each bar, a lost motion link disposed between each displacer and all of the said bars, means for selectively removing the lost motion between this link and any particular bar so as operatively to connect this to the displacer,

and phase varying means for varying the operating phase relationship between dispiacers.

9. A wave-making machine comprising a row of oscillatory fluid displacers, a plurality of bars extending substantially parallel with the row of displacers, means for selectively connecting a bar to a particular displacer, an adjustable drive means connected to each bar for imparting a pre-settable extent of motion to the particular bar; said drive means comprising a variable throw cam and follower combination, said follower being connected to the bar, the variable throw cam and follower including a cam adjusting member having a spiral groove formed therein, said cam being mounted on a rotatable shaft in driven engagement therewith and having means thereon in engagement within said spiral groove whereby rotation by said cam adjusting member 'varies the throw of the cam relative to the rotatable shaft so as to provide means for adjusting the throw of the cam follower; and means included in said drive means for varying the phase of cam follower motion of one bar drive means relative to another, whereby the phase of movement between selective bars and hence fluid-displacers is rendered adjustable.

References Cited in the file of this patent UNITED STATES PATENTS 1,871,215 Keller Aug. 9, 1932 2,002,043 Price May 21, 1935 2,222,010 Witte Nov. 19, 1940 2,663,092 Laurent et al. Dec. 22, 1953

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