US2891179A - Support for vibratory devices - Google Patents

Description

16, 1959 w. CLELMORE 9 L SUPPORT FOR VIBRATORY DEVICES Filed Aug. 19, 1957 INVENTOR.

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SUPPGRT FOR VIBRATORY DEVICES William C. Elmore, Media, Pa., assignor to Aeroprojects, Inc, West Chester, Pa., a corporation of Pennsylvania Application August 19, 1957, Serial No. 678,943

19 Claims. (Cl. 310-26) This invention relates to a support for vibratory devices and to vibratory devices comprising such supports, and more particularly, to a support for vibratory devices used in sonic and ultrasonic operations in which the loss of energy from the devices by absorption and the like is minimized.

Vibratory devices delivering sound energy have been widely used experimentally and industrially to perform various operations such as soldering, drilling, welding, machining, mixing, homogenizing, emulsifying, sterilizing, and the like. In general, these devices comprise a source of alternating electrical current, a transducer for converting the electrical current into mechanical oscillations and a coupler for conducting the vibratory energy developed by the transducer to a desired area. The coupler may also perform the added function of concentrating or diffusing the vibratory energy and of matching impedance between the transducer and the work. For operating purposes, these devices are generally supported in mounts of soft material, by rigid mechanical type mounts, on diaphrag-ms, etc. In operation, the device is excited and the developed vibratory energy is transmitted through the device to the area being worked upon.

' When the vibratory energy is being continuously transmitted by the device, part of the energy is reflected by boundaries such as interfaces, associated with changes in the speed of sound in the materials used. As a result thereof, standing wave patterns are established. When such standing wave patterns are established, certain sections of the vibratory device have zones of minimum motion, called nodes, which recur at one-half wavelength intervals. Other sections of the device have zones of maximum motion, called antinodes or loops, which also recur at one-half wavelength intervals and at a distance of one-quarter wavelength from an adjacent node. Since minimum motion of the vibratory device occurs at nodes, it has been considered desirable with prior devices to support such devices at these parts at which nodes are established to minimize energy losses by absorption.

However, a standing wave pattern exists only on an unloaded or partially loaded vibratory device, i.e. true nodes do not exist on one which is delivering essentially all of its power. In a condition of perfect matching of the load to the vibratory device, which is desirable for maximum utilization of the energy developed, the standing wave patterns characteristic of an unloaded or partially loaded system are not established. Under these circumstances, all of the energy developed by the device is absorbed and none is reflected from the work face back along the device to cause standing wave patterns. Therefore, if the vibratory device is supported by inelastic or semi-elastic attachments, the transmission characteristics of the device are altered and some of the energy is absorbed.

' Even when perfect matching of the load is not achieved, for example when one-half of the available energy of the vibratory device is being delivered so that ice standing wave patterns and nodal zones will exist in the coupler, the nodal zones will still have vibratory amplitude requisite for passage of the delivered half of the energy. If inelastic or semi-elastic attachments are made to the vibratory device, the energy delivered will be reduced still further, even if the attachments are positioned at the so-called nodal zones.

When a vibratory device has a free end, i.e. an end which is not delivering energy, a node will exist, onequarter wavelength from the free end and at odd multiples of one-quarter wavelength, from a free end if the device is longer.

I have discovered that by providing vibratory devices with a resonant member a unit multiple of one-half wavelength long according to the properties of the material of which the resonant member is made and the operating frequency, and having a free end, true standing wave patterns are set up in the resonant member, thus establishing a true node at which the devices can be supported, thereby minimizing losses by absorption of the vibratory energy developed by the device. This permits maximum energy output to the work area instead of complicating energy transmission. The support is simple and inexpensive to make and install and does not restrict the action of the apparatus. It does not require or preclude supporting the device rigidly and permits the device to be applied with force to the area being worked on, as required for drilling, welding, soldering, machining, extrusion, and other heavy-duty applications. The avoidance of energy losses by absorption analogous to leakage, permits the device of the present invention to have special utility for mixing, homogenizing, emulsifying, sterilizing and like operations.

The foregoing supports and vibratory devices including such supports comprise for the support a resonant member one-half wavelength long or unit multiples of one-half wavelength long according to the properties of the material of which the support is made and the operating frequency of the vibratory device with which the support is engaged. Such supports have a node one-quarter wavelength from the free end of the support, or odd multiples of one-quarter Wavelength from the free end of the support, with the other end of the support secured to the unit being supported. Such supports and the apparatus embodiments comprising such supports and the vibratory devices engaged therewith, form the subject matter of 'my copending patent application Serial No. 517,599, en-

titled Vibratory Device, filed June 23, 1955, of which this application is a continuation-in-part. Such supports render the vibratory device with which they are associated essentially force-insensitive regardless of the location on the vibratory device at which the support is secured, i.e. the vibratory device which is so-supported may be applied to a work area with force and under a load with out a significant shift in frequency of the device resulting from the load. While tests have indicated that the position of such supports in the. acoustical system is not critical, and there may be occasions for placing them at other positions in the system such as at a nodal zone, practical requirements indicate the desirability of securmg the support to the vibratory device at an antinode or loop, which is a zone of minimum stress, or as near to.

such an antinode or loop as possible.

Generally, the support is equivalent to one-half wave length long, although for very long transducer-coupler arrays it may be advisable to utilize a support that is equivalent to unit multiples of one-half wavelength in length.

Certain apparatus embodiments comprising vibratory range of operating frequencies.

In still other ultrasonic apparatus embodiments it is difficult to design and/or operate satisfactorily the equipment at a single or precise frequency. Thus, there are ultrasonic apparatus embodiments in which due to ap plied forces associatedwith. temperature changes, etc), the impedance of thesystem is varied significantly during use, disturbing or altering the design or resonant frequency of the apparatus for reasons not associated with the support.

I have discovered that the supports, of. the type disclosed in my. previously identified. copending patent application Serial No. 517,599, and also the supports disclosed in my copending patent application, Serial No. 678,942, entitled Support for. Vibratory Devices, filed on August 19, 1957, which comp-rise supports andvibratory devices in which. the support is constructed so that its wavelength properties are not linearlyproportional to its length, are of prime utility for ultrasonic'equipment in which but' a narrow frequency response is required, and where the operating frequency for the equipment does not appreciably differ from its" design frequency.

This invention has as an object the provision of a support for vibratory devices of the type whichare operated at a plurality of operating frequencies.

This invention has as another object the provision of a support for vibratory devices having a broad frequency response, and which is capable of force-insensitively supporting. such vibratory devices over. a range of varying.

operating frequencies.

This invention has as a further object the provision of novel vibratory devices.

These and other objects are accomplished by the support of the present invention which comprises a plurality of resonant members, a connecting flange. joining said resonant members together at a length from the free end of each resonant member equivalent tonne-quarter wavelength or an odd multiple of one-quarter wavelength of an operating frequency for the device, with each of the members being dimensioned for different wavelengths within the range of operating. frequencies in which the vibratory device engaged by the support operates. In a preferred embodiment of the present invention, each of the resonant members are made from the identical material and varied as to length. However, the separate resonant members may be formed from different materials and dimensioned to the proper wavelength for the material of which each resonant member is made.

Each of the resonant members. should preferably be of substantially uniform thickness throughout its entire length, and such thickness should be less than of the wavelength of'the frequency of operation of the device for which such member is dimensioned which is, of course, dependent upon the material of "which the resonant member is made, although this is not critical. Extending the thickness .to some other thickness below wavelength, as for example A? wavelength, causes a minor reduction inefliciency of the support. The thickness of each of the resonant members shouldnot be so great as to render the member too stiff to be. properly elastic, as will be evident to thosev skilled in the art, and members ofthe tube or shell type should be dimensioned-to preclude radial resonance of the tube at or close to the operating frequency of the system, persons skilled in the art being able to calculate radial resonance by equations such as the equations ofA. E. H. Love on page 546 of A Treatise on the Mathematical Theory ofEl'asticity, 4th revised edition (New York: Dover Publications).

The resonant members may have a wide variety of shapes, and each of the resonant members may comprise cylindrical shells', rods, etc. Preferably, the resonant members are spaced alongside the vibratorydevice, preferably but not necessarily parallel thereto. Thus, in the case of resonant members comprising shells; the resonant members are preferably concentric in respect to the vibratory device. In the case of resonant members comprising rods, the resonant members may be parallel to and spaced from the vibratory device in most cases, although in other cases it is entirely possible and may be advantageous to have the rods extending in a variety of non-parallel directions, such as in ray-form, from their common connection.

Each resonant member is joined to each of the other resonant members by means of a connecting flange which is positioned-one-quarter wavelength or an odd multiple of one-quarter wavelength from a free end of the resonant member. Preferably, such connecting flange is positioned one-quarter wavelength from the free end of each resonant member. An; end of. the innermost member spaced from the connecting flange by a distance of onequarter wavelength or an odd multiple of one-quarter wavelengths, preferably one-quarter wavelength, is engaged with. the vibratory device. The thickness of the flange is. not critical. although increasing; its. thickness.

unduly beyond necessary strength requirements. lowers the high Qnature of the system as wouldbeevidentto. one skilled in thisart. As. a general rule, the thickness. of the flange in the direction of the axis of the system shouldbethe minimum consonant with securing desired strength characteristics. The width of theflange, i.e. its. over-all diameter, is not critical; fact, the flange need.

not be a real circle.

For practical reasons, the support is ordinarily. placed at anantinode or loop, on the vibratory. device, this .being.

a zone of. minimumstress.

The. supports of the present invention may have a range of 1000 cycles: per second, as for example 500 cycles persecond in either side of the center operating frequency.

The support and thevibratory deviceengaged.:therewith may be carried by a member securedtothe connecting flange.

The. present invention also includes. ultrasonic equip;- ment comprising vibratory devices: including a. source of mechanical vibrations, a coupler, andgthe aforesaid;

support which is-engaged with such. vibratory device. For the purpose of illustrating.theinvention there are shown in the drawings forms which are presently preferred; it being understood, however, that this invention;

is not limited to the pfecise arrangements and instrumentalities. shown.

Referring tothe drawings, which-are partlyschematic,

. and whereinllike reference characters refer'to like parts:

Figure 1 isa. side elevational view of a welder of the:

present invention, which includes a support of the present invention.

Figure 2 is a: fragmentary longitudinalsection-of the embodiment of Figure 1. 1

Figure 3 is arfragmentary longitudinal, sectionaofv an-;

other embodiment of the support of the presentinvention.

Figure 4 is a fragmentary longitudinalsection: of another embodiment of the support ofv thepresent invention.

Figure 5 is a fragmentary view, partly in elevation and 2 there isshownthereina welder. designatedgenerally by 10.. The welder 10 is of the. type. described in the.

following patent applications: SerialNo. 467,382,. filed November 8,1954, entitled Method and Apparatus Em- .ploying Vibratory Energy for Bonding Materials, in the name of JamesByron Jones, Carmine F. De Prisco, and' myself, now abandoned, and its continuation in part" patassay-r9 ent applications: Serial No. 579,780, filed April 23, 1956, entitled Method and Apparatus Employing Vibratory Energy for Bonding Metals, in the name of James Byron Jones, Carmine F. De Prisco, and myself; Serial No. 579,779, filed April 23, 1956, entitled Vibratory Seam Welder and Vibratory Seam Welding Process, in the name of James Byron Jones, Carmine F. De Prisco, and myself; or it may be of the type described in Serial No. 610,991, filed September ;5, 1956, entitled Method and Apparatus Employing Vibratory Energy for Bonding Metals, in the name of James Byron Jones, Carmine F. De Prisco, and myself.

The disclosures of the aforesaid patent applications are to be construed as incorporated herein by reference.

The welder 10 includes amagnetostrictive transducer 12 comprising a laminated core of nickel, nickel-iron alloy, Permendur (an iron-cobalt alloy), or an aluminumiron alloy, or other magnetostrictive material such as a ferrite, properly dimensioned to insure axial resonance with the frequency of the alternating current applied thereto so as to cause it to decrease or increase in length according to its coefficient of magnetostriction. Transducer 12 includes a rectangularly shaped opening 14 at its central portion. The elements of a polarizing coil 16 and an excitation coil 18 may be wound through the opening 14 Within transducer 12. The desirability of magnetically polarizing transducer 12 by means of polarizing coil 16 in order for the metal larninations in transducer 12 to efliciently convert the applied RF. energy from excitation coil 18 into vibratory energy Will be readily understood by one skilled in the art.

The operating frequency of the transducer 12 may be varied within a controlled range either continuously or intermittently. 7

Means for varying the operating frequency of transducer 12 (and hence of vibratory welder 10) is designated schematically by numeral 13. The actual construction of means 13 will be readily apparent to one having skill in this art, and forms no part of the present invention.

By the use of means for varying the frequency 13 it is possible to vary the frequency over any intended range. For example, in the illustrated embodiment, the frequency may be varied over a 200 cycle per second range. Thus, if the center frequency at which welder 10 operates is 15,000 cycles per second, the frequency could be varied continuously or intermittently, as desired, over the range 14,900 cycles per second to 15,100 cycles per second.'

In place of transducer 12, other forms of transducing means for producing elastic vibratory energy may be used, such as a transducer stack of laminated strips of metal, associated with a permanent magnet and a source of applied R.F. energy.

The sonotrode 20 or coupling member or jaw member comprises a cylindrical rod portion 22 metal-to-rnetal bonded in end-to-end contact with transducer 12 and a tapered portion 24 whose taper may, but need not necessarily, satisfy the equation set forth at page 163 of Piezoelectric Crystals and Ultrasonics, by Warren P. Mason, published in 1950 by Van Nostrand Company, namely a curved coupling member whose taper is an exponential function of the length and satisfies the relation:

where S equals the original area, S equals the reduced area, T equals the taper constant, and l equals the length of tapered section, and a tip 26 which comprises an enlarged bulb having a curved periphery. The total length of the sonotrode 20 should be an integral number of one-half wavelengths of the transducers frequency in the material of the sonotrode, so that the joint between the transducer 12 and the sonotrode 20 will come at a loop of the wave motion and will not be appreciably strained.

The workpieces 28 and 30 undergoing welding may comprise strips of foil or sheet metal which are supported on anvil 32.

The support for welder 10 comprises the support of the present invention and is designated 34. In the embodiment illustrated in Figure l, the support 34 comprises a pair of oppositely positioned inner rods 36a and 36b formed from stainless steel or the like, spaced from (as for example inch or more) and secured to the cylindrical portion 22 of sonotrode 20 by radially inwardly extending attachment means 38a and 38b. For practical reasons, attachment means 38a and 38b are secured to the cylindrical portion of sonotrode 20 at an antinode or loop on cylindrical portion 22, which is a zone of minimum stress. Rods 36a and 36b have an axial length equal to one-half Wavelength of one of the limits of the frequency range over which the transducer 12 operates.

In the illustrated embodiment wherein the frequency is varied between 14,900 cycles per second and 15,100 cycles per second the rods 36a and 36b may have a length equal to one-half wavelength for the material of which they are made at a frequency of 15,100 cycles per second.

While as above-indicated, each of the rods 36a and 36b in the illustrated embodiment have a length equal to one-half wavelength, and such length is to be preferred, it is to be understood that each of rods 36a and 3611 may have a length equal to a plurality of one-half wavelengths, such as one wavelength, one and one-half wavelengths, etc. In particular, where it is desired that the length of the support be minimal, it is advantageous to restrict the total length of each of the rods 36a and 36b to one-half Wavelength for the material of which such rods are made.

A connecting flange 40a comprising a radially outwardly extending element is positioned at the node onequarter wavelength from the free end 42a of rod 36a. Connecting flange 40a may be arcuately curved about sonotrode 20 and spaced therefrom and extend to and in engagement with rod 36b. However, as in the illustrated embodiment, the connecting flange may not extend radially inwardly beyond rod 36a. A second rod 44a dimensioned as set forth below is secured to connecting flange 40a at end 46a thereof.

The thickness of connecting flange 40a is not critical, although increasing the thickness of connecting flange 40a lowers the high Q nature of the system as would be evident to one skilled in this art. As a general rule, the thickness of connecting flange 40a should be the minimum consonant with securing desired strength characteristics.

Each of the rods 36a, 36b, 44a and 44b should preferably be of substantially uniform thickness throughout its length.

Connecting flange 40a and rods 36a and 44a may be integrally formed from a unitary piece of material, and for example may comprise a single casting of metal. Alternatively, as in the illustrated embodiments, connecting flange .0a and rods 36a and 44a may be formed from separate metal elements of the same metal, such as stainless steel, and welded, brazed, or otherwise fixedly secured together. Preferably, but not necessarily, connecting flange 40a and rods 36a and 44a are formed of the same metal, but the subject invention comprehends forming one or more of these component members from diflerent metals. Thus, rod 36a may be formed of a different metal rod 44a, if both rods are properly dimensioned for the materials of which they are made in accordance with the present invention.

A rod 44b is spaced from and connected to rod 36b by means of a radially outwardly extending flange 40b, being secured thereto at its end 46b.

Flange 40b is positioned at the node one-quarter wave length from the free end 42b of rod 36b.

The rods 36b and 44b may be formed integrally from of 15,100cycles per second. The rods 44a and 4412 are each dimensioned to be equal to one-quarter wavelength or odd multiples of one quarter wavelength of 14,900 cycles per second for the material of which such rods 44a and 44b are made between their ends 46a and 46b secured to their'respective flanges 40a and 40b and their free ends 48a and 48 1;. While, particularly where it is desirable that the support 34- be-or" minimal size, the portion of rods 44a and 44b between the ends 46a and 46'!) thereof secured to flange 40a and their free ends 4812' and 48b should be equal to one-quarter wavelength, it is possible, as above-noted, for such rods to be equal to an odd multiple of'one-quarter wavelength, such as three qnarter wavelengths, one and one-quarter wavelengths, etc

The thickness of eachof the rods 36a, 36b, 44a and 44b is preferably maintained at less than about A of the wavelength for which the rod is dimensioned. Extendingthe thickness to below wavelength, as for example to A; wavelength, causes a minor reduction in efficiency of'the support.

The connecting flange 40a" extends radially outwardly from rod 44a and may be integral with, or brazed, or welded or otherwise fixedly secured to a member 50 which may be pivoted about pivot 52. Force may be applied to the workpieces 28 and 30 undergoing welding at the upper end of flange 402;, as depicted by an arrow surmounted by the letter F in Figure 1'. Notwithstanding the loading ofthe system in the manner indicated, the support 34 will remain essentially force-insensitive since the node for such support will always be at flanges 40a and 40b, and carried by flange 40a. Moreover, the support 34 will remain essentially force-insensitive over the entire frequency range between 14,900 cycles/second and 15,100 cycles/second. This permits welding to be achieved using a varying range of operating frequencies and relatively high clamping pressures, and permitsrelatively large amounts of elastic vibratory energy to be transmitted to the workpieces 28 and 30 from the sonotrode 20. Since the support of the present invention permits welding tobe achieved over a wide variety of clamping pressures it is of great utility with welding units.

Welding may be achieved with clamping pressures which-need not produce an external deformation of more than about in weldments effected at room or ambient temperatures. In many cases the extent of deformation is appreciably below 10% and in some instances may be virtually absent together. The minimal clamping pressure to be used constitutes a pressure sufiicient to maintain the metals being welded in operative disposition, e.g. contacting each other so that the weld may be effected by the application of vibratory energy.

The range of operative clamping pressures which may be employed may be readily ascertained by the user of the process. In all cases the clamping pressure must be sufficient to eifect coupling between the metals being welded and the source of vibratory energy, so that such vibratory energy may be transmitted to the metals.

Welding may be and in many instances is initiated at room temperatures or ambient temperatures without the application of heat; If desired, welding may also be By deformation is meantthe change in dimensions of the weldment adjacent the weld zone divided by the aggregate thickness ot-the weldment members prior to welding; result multiplied by 100 to obtain percentage.

=The weldment may be warm to the touch after the weld due to the application of the elastic vibratory energy.

55 54b, which areeach fixedly secured to an antinode-on initiatedat elevated temperatures below the'fusion temperature (melting pointior: solidus temperature of any ofthe pieces being bonded)?" Thus, heating the metals.

to be welded prior to, and/orduringv welding. to a temperature below their fusion temperature may, in some cases, facilitateithe ease of welding and lower the power requirements and/or time requisite to achieve welding.

The welding process of my invention is applicable to forming both spot andseam welds.

Thewelding process may'be'applied-to a wide variety of metals, examples of which include: pure aluminum to pure aluminum; aluminum alloy to aluminum alloy; copper to copper; brass to brass; magnesium alloy to magnesium alloy; nickel to'nickel; stainless steel to stain= less steel; silver-titanium alloy to silver-titanium alloy; gold-platinum alloy tostainless'steel; platinum to coppery platinum'to stainless steel; gold pl'atinum alloy to nickel;

titanium'alloy to'titaniuin alloy;,molybdenum to molybdenum; aluminum to nickel; stainless" steel to copper alloy; nickel to 'copperalloy; nickelalloy'to nickel alloy;

sintered aluminum powder to sintered' aluminumpowder; etc.

Welding of the aforesaid typemay comprise both In the spot-type welding proc'essembodiment, welding maybe accomplished withina wide-time rangepsuch as a time range of between about 0.001 second to above 6.0 seconds, or somewhat more, With welding under most normal conditions being eifected' during a time interval of fromseveral hundredths of'a second to several seconds.

The welding of most metals can be eifected in the ambient atmosphere. uated atmospheres, or'in selected atmospheres, such as atmospheres comprising an inert gas is also compre hended. Furthermore, while the welding process may be effected with metals, such as aluminum, without the extensive precleaning required to-etfect satisfactory'welding by othermethods,a degree of precleaning and surface treatment may prove advantageous in the welding of many metals. It isdesirable prior to efl'ecting welding to remove surface contaminants, such as hydrocarbon lubricants and the like; In the embodiment of the present invention shown in Figure 3, the support 34a comprises a plurality of rods spaced'from and parallel to the sonotrode 20a (thetransducer and the remainder of the welder in the embodiment shown in Figure 3 may be identical to that of Figure 1). Thus; the support 34a comprises a pair of diametrically'opposed rods 54a and sonotrode 2011 at their respective radially inwardly directed ends 56a and56b'. The remainder of rods 54aand 54b are spaced from and parallel to sonotrode 20a; Thus, the rods 54a and 54bmay be spaced'from sonotrode 20a over the remainder of their length except for 3 The tenztperatures to which the foregoing statements refer are those which can be. measured by burying diminutive.ther mocouples'in' theweld zoneprior to welding, as well as the temperatures which can'- bezestimated ar approximated from a .metallographic. examination, of, a crosssection. of a vibra tory weld in the ordinary magnification range up-to' about 500 diameters.

A mixtureconsistinge of elemental aluminum. and aluminum oxide.

However, welding in highly evac-- 54a and 5412 may each be dimensioned to be equal to a one-quarter wavelength of a frequency of 15,000 cycles,

A rod 64a is carried by flange 58a spaced from and parallel to rod 54a. Similarly, a rod 64b may be carried on flange 58b spaced from and parallel to rod 54b.-

Where the swept frequency range is swept between 14,900 cycles per second and 15,100 cycles per second as in the subject embodiment, each of the rods 64a and 641) may be dimensioned to have a length equivalent to one-quarter wavelength or odd multiples of one-quarter wavelength of one of the limit frequencies, such as the frequency 14,900 cycles per second, and in the illustrated embodiment each of the rods 64a and 64b has a length equivalent to one-quarter wavelength for the material of which it is made at 14,900 cycles per second.

Another rod 66a is carried by connecting flange 58a spaced from and parallel to rod 64a. Similarly, a rod 66b is carried by connecting flange 58b spaced from and parallel to rod 64b. In the illustrated embodiment, each of the rods 66a and 66b may have a length equal to onequarter wavelength or odd multiples of one-quarter wavelength of the limit frequency of 15,100 cycles per second, and as illustrated each of the rods 66a and 66b has a length equal to one-quarter wavelength for the material of which it is made at this frequency.

Each of the rods and their respective connecting flange, namely the rods 54a, 64a, and 66a, and the connecting flange 58a, and the rods 54b, 64b, 66b, and the connecting flange 58b may comprise integral pieces formed from single castings of the same metal. Alternatively, the rods and connecting flanges may be formed of different pieces of the same metal and welded or brazed or otherwise fixedly secured together. In still another embodiment, the rods and connecting flange may be formed of different kinds of metal which may be fixedly secured together.

The thickness of the rods 54a, 54b, 64a, 64b, 66a and 66b and the connecting flange 58a should be regulated as indicated in the embodiment shown in Figures 1 and 2. Thus, the rods should preferably be less than about wavelength thick based upon the wavelength for which they are dimensioned, and the connecting flange should be of the minimum thickness consonant with securing desired strength characteristics.

In the embodiment of the present invention shown in Figure 4, the support 34b comprises a plurality of rods spaced from and parallel to the sonotrode 2012 (the transducer and the remainder of the welder in the embodiment shown in Figure 4 may be identical to that of Figure 1). metrically opposed rods 68a and 68b which are each fixedly secured to sonotrode 20b at their respective radially inwardly directed ends 69a and 69b. The remainder of each of rods 68a and 68b is spaced from and parallel to sonotrode 20b.

Each of rods 68a and 68b preferably has an axial length equal to one-quarter wavelength or an odd mul tiple of one-quarter wavelength for the material of which the rod is made at a frequency within the swept frequency range. Thus, where the range is varied between a frequency of 14,900 cycles per second and 15,100 cycles per second, the rods 68a and 68b may each be dimensioned to be equal to one-quarter Wavelength, or an odd multiple of one-quarter wavelength, of the center frequency of 15,000 cycles per second. In the illustrated embodiment, the rods 68a and 68b are each dimensioned Thus, the support 34b comprises a pair of dia-' to have a length equivalent to three-quarters wavelength of a frequency of 15,000 cycles per second.

A connecting flange 70a extends radially outwardly from rod 680 at the end 72a thereof. Similarly, a connecting flange 701) extends radially outwardly from rod 6311 at the end 72b thereof.

A rod 74a is carried by and fixedly secured to connect ing flange 70a and is spaced from and parallel to rod 68a. Similarly, a rod 74b is carried by and fixedly secured to connecting flange 70b. The over-all length of each of the rods 74a and 74b is dimensioned to be equivalent to one-half wavelength or multiples of one-half wavelength, such as one wavelength, one and one-half wavelengths, etc. In the illustrated embodiment, each of the rods 74:: and 74b has a length equal to one-half wavelength and project on either side of their respective connecting flanges 70a and 70b about one-quarter wavelength. Where the rods 74a and 74b have a length equal to a multiple of one-half wavelength, the rod should be so carried that at one side it is one-quarter wavelength, or odd multiples of one-quarter wavelength, from a free end.

In the illustrated embodiment in which the frequency is swept between the range 14,900 cycles per second and 15,100 cycles per second, each of the rods 74a and 7412 have a length equal to one-half wavelength at a frequency of 15,100 cycles per second.

A rod 76a is also carried by and fixedly secured to connecting flange 70a. Similarly, a rod 76b is carried by and fixedly secured to connecting flange 70b. Rods 76a and 76b are each dimensioned to have a length equivalent to one-half wavelength or multiples thereof. In the illustrated embodiment, rods 76a and 76b are each dimensioned to have a length equal to one-half wavelength and project about one-quarter wavelength on either side of connecting flanges 70a and 70b.

For the swept frequency range of the illustrated embodiment, namely a swept frequency range of between 14,900 cycles per second and 15,100 cycles per second, each of the rods 76a and 76b have a length equal to one-half wavelength at a frequency of 14,900 cycles per second.

The thickness of the rods 68a, 68b, 74a, 74b, 76a and 76b and the connecting flange 70a should be regulated as indicated in the embodiment shown in Figures 1 and 2. Thus, the rods should preferably be less than about wavelength thick based upon the wavelength for which they are dimensioned, and the connecting flange should be of the minimum thickness consonant with securing desired strength characteristics.

In the embodiment of the present invention shown in Figure 5, the support 80 comprises a pair of concentric shells 82 and 84 joined together by a connecting flange 86 and concentrically disposed about sonotrode 20c. Shell 82 is fixedly secured to sonotrode 20c by means of a radially inwardly directed flange 88. The shell 82 may have an axial length equal to one-half wavelength or multiples of one-half wavelength for a frequency within the operating frequency range, preferably, a limit frequency. In the illustrated embodiment, shell 82 has an axial length equal to one wavelength at a frequency of 15,100 cycles per second (the sonotrode 20c operating within the swept frequency range between 14,900 cycles per second and 15,100 cycles per second). The connecting flange 86 is positioned at the node one-quarter wavelength from the free end 90 of shell 82. The connecting flange 86 may be supported upon or engaged with a support means (not shown).

The shell 84 which is fixedly secured to connecting flange 86 and concentrically disposed in respect to shell 82 has a length equal to one-quarter wavelength or an odd multiple of one-quarter wavelength of an operating frequency, preferably, a limit frequency. In the illustrated embodiment, the shell 84 has a length between its free end 92 and connecting flange 86 of three- 11 quarters wavelength for the frequency 14,900 cycles per second.

The thickness of the shells 82 and 84 should be preferably less than about wavelength thick based upon the Wavelength for which they are dimensioned, and in any event should be thin enough so that the introduction of undesirable stiifness is avoided. The connecting flange 86 should be of the minimum thickness consonant with securingdesired strength characteristics.

The shells 82 and 84 and connecting flange 86 may be formed in an integral piece from the same metal, as by a single metal casting, as in the illustrated embodiment. Alternatively, the shells 82 and 84"may each be welded, brazed, or otherwise fixedly securedto the connecting flange 86.

The present invention may be embodied in other specific forms without departing from thespirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention.

I claim:

1. A support for a vibratory device which may be operated at a plurality of frequencies, said support comprising a plurality of resonant members joined together by a connecting flange, said connecting flange including means for carrying the support, one of said resonant members having means for fixedly securing-thesupport to the vibratory device at a spaced distance from said vibratory device, each of' a plurality of saidresonant members 'beingjoined to said connecting flange at an axial distance from one free end of each said resonant member, said axial distance for each said resonant member being approximately equal to an odd multiple of one-quarter Wavelength of an operating frequency of the device for the material of which such resonant member is made, with a plurality of said resonant members having diflferent Wavelength" axial dimensions.

2. A support inaccordance with claim 1. in which each of the resonant members has a thickness of. less than $6 wavelength of the operating frequency for which it is dimensioned.

3. A support in accordance withclaim. 1 in which a plurality of the resonant members comprisecylindrical shells, said cylindrical shells being concentrically arranged and joined together by the connecting flange which extends radially outwardly in respect to said shells, with the innermost of said shells having a radially inwardly directedfl'ange as the means for fixedly securing the support to a vibratory device.

4. A support in accordance with. claim 1 in which each'of the resonant members comprises a bar.

5. A support in accordance with claim 1 in which at least one of said' resonant members joined to the connecting flangeis provided with. but a single free end.

6. A support in accordance with claim 1 in which the axial distance between the connecting. flange and the free end of each of a plurality of the resonant members is approximately equal to one-quarter wavelength of an operating frequency of the vibratory device for the material of which the-resonant memberis made;

7. A support in accordance with-claim 1 inwhich each of the resonant members and-the connecting flange is formed from the same material.

8. A support in accordance with-claim l in which at least one of the resonant members' connected to the connecting flange projects axially outwardly on both sides of the connecting flange withthe axialdimension of each portion of said resonant member on either side of the connecting flange being approximately: equalto an odd'multiple of one-quarter wavelength of an op crating frequency of the vibratory device for the material of which said're'sonant'member is made.

9. A support in accordance with claim 1 in which the resonant member having. means for fixedly securing the support to the vibratory device is'provided with such means at one end thereof, with the other end thereof being joined to the connecting flange.

10. Vibratory apparatus including a vibratory device which may be operated'at-a plurality of frequencies, said device including means for producing mechanical vibrations and a coupler for transmitting such-vibrations, and a support for said device secured to said coupler, said support c'onipri's'ing'a plurality of resonant members joined together by a connecting flange, said' connecting flange including means'for carrying the support, one of said resonant members having means for fixedly securing the support to said vibratory device at a spaced distance from said vibratory device,v each of'a plurality of said resonant members being joined to said connecting flange a't'an axial distance from one free end of said resonant member, said axial distance for each said resonant member bein'geq'ual to an odd multiple of one-quarter wavelength of an operating frequency of said device for the material of which such resonant member is made, with a plurality of said resonant menioers having difierent Wavelength dimensions. 7

11. Vibratory apparatus in accordance with claim 10 inwhich the support is secured to the coupler at an antinodeon' the coupler.

I2. Vibratory apparatus in accordance with claim 10 in which" each of the supports resonant members has a thickness less than ,4 wavelength of an operating frequency for which it is dimensioned.

13. Vibratory apparatus in accordance with claim 10 in which a plurality of the resonant members comprise cylindrical shells, said. cylindrical shells being concentrically arranged and joined together by the connecting flange which extends radially outwardly in respect to said shells, with the innermost of said shells having a radially inwardly directed flange as the means for fixedly securing the support to said vibratory device.

14. Vibratory apparatus in accordance with claim 10 in which each of the resonant members comprises a bar.

15. Vibratory apparatus in accordance with claim 10 in which at least one of saidres'onant members joined to the connecting flange is provided with but a single free end;

16. Vibratory apparatus in accordance with claim 10 in which the axial distance between the connecting flange and the free end of each of a plurality of the resonant members is approximately equal to one-quarter wavelength of an operating frequency of the vibratory device for the material of which the resonant member is made.

17. Vibratory apparatus in accordance with claim 10 in which each of the resonant members and the connectiirg flange is formed from the same material.

18'; Vibratory apparatus in accordance with claim' 10 in-=whichat least'one of the resonant members connected to the connecting flange projects axially outwardly on both sides of the connecting flange with the axial dimension of each portion of said resonant member on either side of the connecting flange being approximately equal to an odd multiple of one-quarter wavelength of an operating frequency of the vibratory device for the material of'which said 'resonantmember is made.

19. Vibratory apparatus in accordance with claim 10 inwhich the resonant member having means for fixedly securing thesupport to the vibratory device is provided with such'means ato'ne' end there'ofl'with the'othe'r end 5 thereof-being joined to the connecting flange.

No references cited.

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