CA2153150A1

CA2153150A1 - Device for ultrasonic cutting and/or ultrasonic welding of webs

Info

Publication number: CA2153150A1
Application number: CA 2153150
Authority: CA
Inventors: Stefan Kipp
Original assignee: Individual
Current assignee: Vaupel Textilmaschinen KG
Priority date: 1993-02-04
Filing date: 1994-01-05
Publication date: 1994-08-18
Also published as: KR960701254A; EP0682725A1; CN1094344A; AU5859494A; WO1994018373A1; JPH08506060A; BR9405822A

Abstract

The operative part (20) of a device for cutting or welding webs consists of an oscillation generator divided into several sections and comprising a piezo element (21), and a horn radiator which amplifies the sonic energy generated in the oscil-lation generator (26) and transfers it to the web via the end of the horn (28).
To improve efficiency and save space, the horn radiator (26) as per the inven-tion is fixed directly on the piezo element, on the opposite side of which is located only a counter-section (22) of the oscilla-tion generator. These three components are firmly secured together and form a novel combination (20). In this arrange-ment, the axial length (32) of the counter-section (22) is smaller than or equal to 1/8 of the effective sonic wavelength, while the axial overall length (38) of the com-bination (20) is smaller than or equal to 3/4 of the sonic wavelength.

Description

FILE, Pt~tN TH~ h~
~E3tT TRAN~L~TION

Device for ultrasonic cutting and/or ultrasonic welding of webs The invention is directed towards a device of the type described in the 5 preamble of claim 1, the active component of which is composed of a multiple member oscillator and a horn radiator amplifying these oscillations (DE-39 25 788 A1).

In order to manufacture strips, for example strips of labels, a broadloom web 10 is firstly woven in which the desired pattern is produced numerous times in adjacent areas of the web. The broadloom web is then cut along the joining point between these web areas. Heated wires which produced a fusion cut in the woven web and additionally fused together the cut ends of the threads were originally used for this. The fused edges resulting from this were hard, 15 however, and caused problems which required additional measures (DE-39 37 947-A1). In order to improve quality problems with cutting, ultrasonic cutting is already being used with weaves (EP-0 534 300-Al).

EP 0 341 942 A2 is directed towards a hand tool for cutting brittle material.
20 It is not recognised that with a length of a half wavelength, flat resonance curves are produced and as a result it is no longer necessary to have matching of the length of different apparatuses to a specific acoustic wavelength. It is not obvious to provide a plurality of individual cutting devices for cutting parallel strips from a common web, the piezo elements of which 25 can be driven by a common generator.

FR 23 13 186 A shows a support composed of two matched oscillatory components, wherein the sonotrode is fitted into one component and an anvil into the other component. The sonotrode also includes an effective section 30 and has an axial length of one complete wavelength. These sonotrodes have narrow resonance curves. Although several sonotrodes are used for cutting ~ 2153150 one web, because of unavoidable tolerances the resonance curves of these sonotrodes are so far apart from each other that generators effective in corresponding oscillation ranges have to be used for driving their oscillators.

5 DE 38 13 176 Al shows several sonotrodes fixed to a common tool on a unit the length of which is one complete wavelength. Narrow resonance curves occur. The sonotrodes cannot be driven by a common generator.

GB 14 66 862 A relates to a cleaning device which is not suitable for cutting 1 0 webs.

GB 20 23 965 A shows a sonotrode with a length corresponding to 3/4 of the acoustic wavelength. These sonotrodes are not suitable for being driven by a common generator.
The above-mentioned known devices for ultrasonic cutting required a large amount of space and had to have a length, on the one hand of their oscillator and on the other hand of their horn radiator, which was exactly matched to the alternating voltage frequency of the generator driving them. This will be explained later in more detail with reference to Fig. 2. The known devices had very sharply delimited resonance curves which required exact matching of the axial length of the oscillator with the length of the acoustic waves generated by the piezo element of the oscillator. Even with devices of the same constructional type, production inaccuracies caused such different resonance curve positions that a separate generator had to be used for driving each device. The alternating voltage of these different generators had to be adjusted according to the respective resonance frequency of the associated device. Due to the size and large number of components, the known devices were relatively expensive. Lastly, there was a relatively low degree of efficiency.

` 2153150 The object of the invention is to develop an inexpensive device of the type described in the preambie of claim 1, distinguished by compact construction and efficient, reliable operation. This is achieved according to the invention according to the measures set out in the characterising part of claim 1, the 5 particular importance of which is described below.

The invention already shortens the axial length of the device in that it uses only the piezo element from the oscillator and the counter section directed away from the web, and they are clamped directly to the horn radiator. This 10 results in a new component which combines the counter section and the piezo element with the horn radiator, and therefore will be hereinafter referred to bythe abbreviation "combination". The invention also departs from the dimensions of the components of the oscillator and horn radiator typical according to the state of the art and uses an axial length for the counter 15 section which is at the most 1/8 of the acoustic wavelength, and a total axial length for the combination which is at the most 3/4 of the acoustic wavelength.
Due to the substantially shorter axial length of the device according to the invention, the cross-section thereof can also be reduced. In this way, not only space, but also a great deal of material is saved, which is important 20 particularly when expensive materials are used. It has been shown that in practice, in contrast to the prior art, the device according to the invention produces a flat resonance curve which no longer necessitates exact matching of the lengths to the given acoustic wavelength.

25 This will be explained in more detail. It is also possible according to the invention to connect several combinations, operating independently from one another, in parallel to a common generator. In this way it is easily possible, for example, to supply alternating voltage to all the cutter combinations provided on a weaving loom by means of a common generator.
Further measures and advantages of the invention will be apparent from the 21531~0 following description and drawings. The drawings show the state of the art and the invention is shown in several embodiments. The drawings show in:

Fig. 1 a component of a weaving loom shown in perspective and partly schematically, with several combinations according to the invention which cut strips for labels from the broadloom web produced, Fig. 2 a partial axial section through the active part of a device according to the state of the art, Fig. 3 two resonance curves, shown schematically, one for the known device according to Fig. 2, and the other for the combination according to the invention shown in Figure 4, 15 Fig. 4 the combination according to the invention drawn to approximately the same scale as the view in Fig. 2, which forms the active part of the invention, Fig. 5 a greatly enlarged view of the lower part of the combination according to Figure 3, Fig. 6 a cross-section through a weaving loom with a different configuration to that in Fig. 1, 5 Fig. 7 an approximately actual-size view of a part of the cross-section shown in Fig. 5, and Fig. 8 a further application of the combinations according to the invention in a punching tool.
A web 10 is produced on a weaving loom shown in Fig. 1 by weaving of warp ~ 21~3150 threads 11 and one or more weft threads 12 in a manner normal in the textile industry. In this way any pattern 13 can be woven in, which is of particular interest when labels are to be woven on this weaving loom. In this case, the patterns 13 of the labels are produced in a large number of adjacent areas as 5 a broadloom web. Multiple cutting devices 20 are then brought to this web 10, whereupon longitudinal cuts 14 are produced at the desired positions, which cut the web 10 into individual strips 15. In accordance with the weaving process in which the warp and weft threads 11, 12 are knotted, the cut strips 15 are withdrawn in the direction of the arrow 77. Then, according to the 10 length of the pattern 13, they are cut into the sections required and form the labels which can be attached to clothing or the like.

The present instance relates to a cutting device which operates using ultrasound. It is provided with a generator 50 shown in Fig. 1 which produces 15 higher frequency voltages, for example between 20 and 30 kHz, from normal alternating electrical current, and supplies an active part 20, which will be described in more detail later, of the device according to the invention by means of electrical cables 31. This active part 20 is located, for example, on the face side 16 of the web, and is associated on the opposite, reverse side 20 of the web with a passive part 30 which hereinafter will be referred to as the "anvil". The web 10 to be cut is located between the active part 20 and the anvil 30. As will be explained in more detail later, in the active part 20 the electrical alternating voltage is converted into ultrasound of the same frequency, and after amplification of the oscillation amplitude, is transferred 25 to the web 10 as oscillatory energy. The active part 20 acts as a hammer and performs a mechanical hammer action of 20 to 30,000 impulses per second with its end 28 which comes into contact with the web. The friction created by this hammer action produces heating of the web material and can be used for separating or welding the web 10. When a sharp hammer end 28 is used, 30 ultrasonic cutting takes place, and a flat hammer end produces welding. The edges along the cut fuse so that fraying of the material at the positions of the cuts 14 is prevented. Supplementary to, or instead of fusing the web material, mechanical destruction of the web at the positions of the cuts 14 can be performed. Thus non-fusible material, such as cotton threads, which can be separated by the horn end can also be used in the web 10.

The known active part 20' had the following appearance, as shown in Figure

2. The electrical oscillating signals coming from the generator mentioned are converted into mechanical oscillations in an oscillator 24'. The oscillator 24' is divided into three axial sections 21', 22'. 23', of cylindrical configuration and 10 connected to one another by means of an axial screw 18'. The electrical signals arrive at two piezo-electrical ceramics 25' which when operating oscillate in phase opposition with respect to one another and form a first axialsection 21' of the oscillator 24', which will hereinafter be referred to as the "piezo element". The piezo element 21' is connected between the two other 15 axial sections 22', 23', which are composed of different materials from one another. The piezo element 21' produces acoustic oscillations which are transmitted to the other axial sections 22', 23' located on either side thereof in very different ways. As little acoustic energy as possible should be transmitted to the outer axial section 22' as consequently this is made from 20 steel and hereinafter will be referred to as the "counter section". The thirdaxial section of the oscillator 24', located on the opposite side of the piezo element 21', should, on the other hand, receive as large an amount as possible of the acoustic energy generated and transmit it to the horn radiator 26' which is to be described in more detail hereinafter. Because of this, this 25 axial section 23' is hereinafter referred to as the "effective section" of the oscillator 24'. This effective section 23' is made from aluminium.

The horn radiator 26' is connected by means of a threaded pin 19' solely to the preceding effective section 23' and is made from costly titanium. The task 30 of the horn radiator is to enlarge the amplitude of oscillation of the ultrasound waves coming from the oscillator 24', and it is provided with a taper 27'. The 2 1 ~ 3 1 ~ O

horn end 28' comes into contact with the web and has sharpened cutters 29' when the previousiy mentioned cuts have to be produced. The length measurement 36' of the horn radiator 26' is configured as approximately double the length 33' of the effective section 23', and therefore only its two 5 ends are shown in Fig. 2 to save space.

The individual sections of the oscillator 24' have to be provided with an axial length 32', 33', 36' shown in Figure 2 which is exactly matched to the ultrasound oscillation used, in order for the horn end 28' to produce sufficient10 acoustic energy. The ultrasound produced in the active part 20' leads to so-called "standing waves" which have a high amplitude antinode and a zero-amplitude node. The standing waves have a wavelength which is dependent on the one hand upon the ultrasound frequency and on the other hand upon the medium in which they are formed. Although the standing waves are 15 longitudinal waves, for clarity in the right hand side of Fig. 2 the associated standing wave 37' is shown in the form of transversal oscillations. In order to obtain the optimum energy yield at the horn end 21' it was necessary according to this state of the art to exactly match the ultrasound frequency to the axial lengths of the individual sections, as follows:
In the oscillator 24', a node 35' of the standing wave 37' should occur centrally between the two piezo-electrical ceramics 25', and the outer counter section 22' should have an axial length 32' which corresponds to exactly a half wavelength that is to say A/2, taking into account the speed of sound within 25 the material it is made from. Then an antinode 34' occurs at the top end of the counter section 22'. Taking into account the material used in the effective section 23', its axial length 33' must also correspond to the half wavelength A so that an antinode 34' occurs at the interface with the horn radiator 26'.
The total axial length of the oscillator 24' according to Fig. 2 is thus A. In other 30 known devices the axial length of this component was A/2 or an integral multiple thereof. This also applies to the axial length 36' of the horn radiator 21~31~0 26' which, as shown in the shortened representation of the standing wave 37' in Fig. 2 also has to be equal to the wavelength A or an integral multiple thereof. The taper 27' additionally has to be taken into account. An effective antinode 34' occurs at the horn end 28' only then. The antinode 35' lies within 5 the axial length 36'. As shown, the known active part 20' according to the state of the art has a total length 38' which is at least equal to doub~e the acoustic wavelength in the different materials concerned, that is to say 2 . ~.
The individual sections of the known active part 20' have a large diameter 39' corresponding to the long length 38'.
As already mentioned, the active parts 20' of the known cutting devices have a sharp resonance curve 51' which is shown in Fig. 3. Here, the vibrational energy E to be transmitted is plotted in relation to the effective acoustic frequency f. The known resonance curve 51' is very sharply defined at the 15 effective resonance frequency fO. Even a small difference in the acoustic frequency generated leads to detuning so that a stable antinode 34' of the standing wave 37' no longer occurs at the contacting horn end 28'. It therefore became necessary to exactly match the axial lengths 32', 33', 36' to the effective ultrasound frequency. Matching is normally done by means of the 20 alternating voltage generator, the electrical output frequency of which has to be correspondingly re-adjusted.

Because of this, until now two active parts 20' of the same known design were each driven by separate alternating voltage generators. Tolerances already 25 occurring during manufacture lead to differences in the axial lengths 32', 33', 36' which necessitated different settings of the resonance frequency fO. A largecost in terms of machines and space was thus involved if a broadloom web 10 were to be cut into many woven strips 15 by numerous ultrasound cutting devices 20, according to Fig. 1. In addition, with the known active part 20', 30 the piezo-element 21' had to be driven in a pulsed manner, that is to say with resting phases.

The invention provides a significant improvement with respect to the state of the art. This can already be seen from the corresponding active part 20' according to the invention shown in Fig. 4. The same reference numerals are used for the designation of analogous components as used for the active part 5 20' according to the invention, shown in Fig. 2, however, to differentiate them they are shown without the prime symbol ('). It is also sufficient to examine differences and special features as the preceding description is otherwise applicable.

10 A special feature of the active part 20 according to the invention is in that the horn radiator 26 sits directly on the piezo element 21, which also in this case is composed of two piezo-electric ceramics 25 and is supplied with alternating electrical voltage by the generator 50 according to Fig. 1 by means of the electric cables 31 shown in Fig. 4. Apart from the horn radiator 26 and the 15 piezo element 21, only a counter section 22 is provided. These components 26, 21 and 22 are firmly braced against one another directly by an axial screw 48. The shaft of the screw 48 penetrates an axial bore in the counter section 22 as well as in the two ceramic discs 25 of the piezo element 21. Because of the electrical connections of the cables 31, in some areas the shaft is 20 insulated by means of a sheath 47. The end of this screw 48 engages directly in a threaded bore 46 of the horn radiator 26, configured as a blind hole. In the invention, a new, combined active part 20 is created by these components, which hereinafter will be referred to as the "combination". Apart from the fact that the combination 20 according to the invention lacks a 25 component according to the invention corresponding to the effective section 23' of the active part 20', as can be seen by comparing the two drawings, on the one hand of Fig. 2 and on the other hand of Fig. 4, drawn approximately to the same scale, the axial lengths according to the invention are much shorter. Because of this the diameter 39 of the components can also be 30 correspondingly reduced and the cost of material is substantially less with the invention 20 than for the state of the art 20'.

215~150 Shortening of the axial length 32 of the counter section 22 occurs because it needs only to be configured as equal to a maximum 1/8 of the effective acoustic wavelength A. In the embodiment shown in Fig. 4, the counter section 22 is made from stainless steel and has an axial length 32 which 5 corresponds to only 1/16 of the effective acoustic wavelength. Surprisingly, it has been shown that this axial length 32 can vary significantly without substantially detracting from the good quality of the cutting or welding. This also applies to the axial length 36 of the horn radiator 26 belonging to the combination 20, which as has been shown in practice, can easily vary in a range of between 7/16 to 10/16 of the effective acoustic wavelength. This will be explained in more detail later, with reference to Fig. 3. In the present casea so-called "hard aluminium", that is to say an alloy of aluminium, magnesium and silicon is used for the horn radiator 26. In the present case the horn radiator has an axial length 36 of approximately 3/8 A measured from the 15 centre of the piezo element 21. With this, the total length 38, which can be seen in Fig. 4, of the combination 20 is approximately A/2, that is to say it isonly 1/4 of the total length of the known active part 20' shown in Fig. 2. Fig.
4 shows the standing wave 37 sensed for the combination 20 in an analogous manner to that shown in Fig. 2. In the direction of the X-axis, the plotted 20 amplitudes of the mechanical oscillations occurring are shown in a logarithmic scale. As can be seen, a very large amplitude antinode 34 occurs at the horn end 28, whereas a node 35 is created approximately in the centre of the piezo element 21. This advantageous standing wave configuration results from the followi ng further construction of the combi nation .
The horn radiator 26 of the combination 20 according to the invention has a particular end section 40 according to Figs. 4 and 5 made from different materials. The horn end 28 which also in this case is provided with a cutter 29 is composed of an end piece 41 which is made from steel with a hardness 30 greater than Rockwell hardness 60. The top section 43 terminates in a taper 27 and continues as the cylindrically configured end piece 41. The end section 21~31~0 40 of the horn radiator 26 is braced by means of its top section 43 by a threaded pin 49 which is screwed at both ends into blind-hole type threaded bores 59, as can best be seen in Fig. 5. In order to compensate for the negative effect of the oscillation, between the end piece 41 a spacer 42 is 5 used, which is preferably made from pure titanium. This spacer 42 has the task of reducing losses during transition of the vibrational energy. The spacer 42, configured as a titanium ring, is axially penetrated by the threaded pin 49 and damps the oscillations in the area of the threaded pin 49.

10 It is important to ensure good surface contact between the end face 44 of thethreaded pin 49 on the one hand and an end surface 54 of the threaded bore 59 on the other hand, as shown in Fig. 5. For this, the threaded pin 49 is provided with a radial extension 45 with a conical end face 44. The end surfaces 54 of the threaded bore 59 on the one had in the end piece 41 and 15 on the other hand in the top section 43 of the horn radiator 26 have a corresponding, complementary counter-conicity. By means of this surface contact axial force is transmitted well also in the area of the threaded pin 49.
As shown in Fig. 3, the combination 20 according to the invention has a 20 completely different, advantageous resonance curve 51 compared to the state of the art, which has a wide, largely flattened maximum in the area of the resonance frequency fO. The resonance curve 51 can deliver practically the same energy at the horn end 28 in a substantial frequency range l~f, which lies between two frequency limits f1 and f2 Iying on either side of the 25 resonance frequency fO. As has been described in the present description of Fig. 4, this means that the measured lengths 32 on the one hand and 36 on the other hand can be changed without detracting from the high efficiency of the combination 20. Thus it is not dependent upon keeping the total length 38 described of the combination 20 to a half wavelength A/2. Differences are 30 perfectly possible. This has the great advantage that now, as shown in Fig.
1, in all cases, all combinations 20 of the same type provided on the weaving 2 1 ~ 3 1 5 0 loom can be easily connected to the same alternating voltage generator 50.
This brings about significant simplification and the following advantages:

The combinations 20 can be attached to a common rail 52 according to Fig.
5 1, which runs at right-angles to the direction of transport 77 of the broadloom web during weaving. For the purpose of individual adjustment of the width 55 of the individual strips 15 produced by the ultrasound cutter 14, the distance apart between the combinations 20 can be changed. The anvil 30 on the opposite side of the web is common to all the combinations 20 and is 10 composed of a continuous rod which also runs at right-angles to the directionof transport 77 of the web 10. As the cross-section in Fig. 6 more clearly shows, the anvil 30 is configured as a hollow tube 53 and its interior is filledwith a deformable material 102 with a high specific gravity, in the present casenamely with lead. This can also be seen in Fig. 7, which shows the following 15 additional, important details of the invention.

The fastening of the combination 20 to the rail 52 is done by means of a specially configured housing 60 which may be made from polypropylene. It has to be an elastic material which produces two deformable hooks 61 at a 20 distance apart from one another. The rail 52 has associated continuous strips56 which are engaged by the hooks 61 in a mirror-image manner. The hooks 61 engaging the strips 56 are spring-tensioned by the material and retain the housing 60 on the rail 52 by means of friction. The housing 60 has a removable cover which, although shown removed in Fig. 7, can be fixed, for 25 example by screws or the like, to the position designated 62.

The housing 60 includes a central chamber 63 in which the previously described combination 20 is held. The combination 20 is additionally pressed by means of a spring 65 against a defined seat surface 64 in the interior of 30 the chamber 63. The said end section 40 of the combination protrudes from the housing. The spring 65 is clamped onto the top end face of the counter 21~3150 section described of the combination 20 by means of a plastics ring 67 made from polytetrafluor ethylene and an elastomer ring 66 made from silicon. The opposite end of the spring 65 lies directly on an internal surface of the housing 60. A hose 70 which can supply cold air, is arranged in an outer 5 chamber 68 of the housing 60 and opens out, as shown in Fig. 7, into the lower area of the central chamber 63 described. The cold air sweeps the combination 20 and conducts the heat through an aperture 69 in the housing 60 to the outside. The hose 70 terminates, also in the top area of the housing 60, in a hose coupling, not shown in more detail, onto which a hose connector 10 71 can be connected, as shown in the disconnected state in Fig. 7, which fits on a cold air supply hose 72.

The electrical cable 31 for said piezo element of the combination 20, already described several times, is located in the outer chamber 68, and is conducted 15 through an aperture in a separating wall 73 which lies in the housing 60 between the two chambers 63, 68. This electrical cable 31 then terminates in a connecting socket 74 arranged in the top area of the housing 60, in which if required a corresponding connecting plug 75 can be coupled, shown in a disconnected state in Fig. 7. The connecting plug 75 fits on a continuing 20 section 76 of electrical cable, which is described in more detail with reference to Fig. 6.

Fig. 7 shows how the horn end 28 of the end section 40 presses the web 10 against the anvil 30 on the opposite side, and during the withdrawal 25 movement 77 of the web 10 during weaving produces the ultrasound cutting 14 by means of its horn end 28. A further special feature of the invention is that the combination 20 according to the invention can be operated continuously, that is to say without rest phases. In order to be able to maintain the resonance according to the state of the art it was until now necessary to 30 have a pulsed drive. The previously described cooling facilitates this continuous operation of the piezo elements in the invention.

`` ~ 21~3150 For accurate position adjustment of the housing 60 and of the combination 20 held therein on the rail 52, a toothed rack 57, which can also be seen in Fig.
1, is used, which is attached parallei and laterally to the rail 52. The toothedrack 57 projects through a lateral gap in a bore 78 of the housing, which extends substantially parallel to said central chamber 63, and opens out at the top end of the chamber 60. The housing 60 also has a blocking member 82, which blocks the housing in the desired position on the rail 52. In the present case, this blocking member 52 is composed of a toothed wheel which is held, usually in permanent toothed engagement with the toothed rack 57, by an elastic member 83, in this case a helical spring. Adjustment of the housing 60 is then blocked. The elastic member 83 can be arranged in an axial extension of the previously described bore 78.

An adjusting tool 80 shown in Fig. 7 is used for longitudinal displacement of the housing 60 on the rail 52, which is in the form of a shaft with a pinion toothing 87 on the shaft end, matched to the toothed rack 57. To adjust the housing 60 the shaft of this adjusting tool 80 is firstly moved in the directionof the axial arrow 79 through the aperture into the interior of the bore 78, so that the pinion toothing 57 engages with the toothed rack 57. If the adjusting tool 80 is then rotated in the direction of the arrow 84 shown in Fig. 7, the pinion 81 rolls over the toothed rack and in a corresponding manner moves the housing 60 along the rail 52. The shaft of the adjusting tool 80 is rotatably mounted in the housing bore 78. When the adjusting tool 80 is axially inserted, the blocking member 82 is simultaneously rendered ineffective. In the present embodiment the toothed wheel 82 is pushed back by the effect upon it of the elastic member, and releases the toothed rack 57.

Fig. 6 shows a different embodiment from that it Fig. 1. In this case a double rail 58 running over the broadloom web 10 is used, which is provided with two rail parts 52, 52' of the type described. Two groups of housings are clamped on the outside faces of the rails 88, 88'. In this way the ultrasonic cutting 14 described with reference to Fig. 1 can be set more narrowly than corresponding to the width 86 of the housing 60 shown in Fig. 1. The housing 60 located on the other rail part 52' can be arranged in the area of the gaps between the groups of housings 60 on the rail part 52 of this double rail 58.
5 The two rail parts 52, 52' of the double rail 58 are arranged at a defined angle with respect to one another as well to a guide 90 of the woven web. This guide 90 supports the corresponding two anvils 30, configured as filled pipes 53, 53'.

10 As can be seen in Fig. 6, the broadloom of warp threads 11 and weft threads 12 already described with reference to Fig. 1 is at the weaving position designated 85 in Figure 6. The broadloom is then transport~d around a heated rod 87 located in an expander. From there, the web 10 runs over a threaded rod 89 and then over the first pipe 53' described onto which a group 15 of the combinations 20 located in the housings 60 is pressed and the first group of separating cuts is produced in the web 10. This threaded rod 89 has the purpose of maintaining the desired width of the web 10 during the withdrawal movement 77. Those areas of the web which have not yet been cut through are then transported over the second pipe 53 and divided by the 20 combinations 20 attached to the rear rail part 52. The completed cut strips 15 are then transported over a further threaded rod 91 as shown in Fig. 6, where they are diverted and transported to drawing-off rollers of the weaving loom not shown in more detail.

Between the two rail parts 52, 52' of the double rail 58 there is a gap 92 which although upwardly open, is closed by a shaped cover 93 removable for mounting. The shaped cover g3 can carry electrical coupling elements 94 onto which the electrical cable sections 76 already described with reference to Fig.
7, for the individual housings 60 can be electrically contacted by means of complementary electrical connection parts 95. The electrical cables 31 already described with reference to Fig. 1 project from the coupling elements 94 and are conducted inside the space 92 between the rails to the common alternating voltage generator 50 described. The electrical components 96 used for operating the combination 20 can also be arranged in this space 92, mounted on a printed circuit board 97 as shown in Fig. 6 fitted onto an 5 inwardly pointing leg of the shaped cover 93. In a similar manner to the electrical cable section 76 shown in Fig. 6, the hose supply lines 72 described with reference to Fig. 7 can be connected to the shaped cover 93 by means of associated hose connectors not shown in more detail. The supply hoses 99 for cold air shown in Fig 6 are arranged in the space 92 enclosed by the rails 58, 93. The supply hoses 99 are connected to a source supplying cold air at the end of the rail 58.

Fig. 8 shows a modified embodiment in which several of the combinations 20 according to the invention are provided with a common tool part 100. In the 15 present case, this tool part 100 is a stamping die which determines the shapein which the stamped item will be cut out of a web, not shown in more detail, by means of its working profile 101. In the embodiment illustrated, the working profile 101 is a hexagon. This tool part 101 replaces end pieces 41 described with reference to Fig. 4, of the individual combinations 20. This application is20 possible as a result of the wide resonance curve, already explained with reference to Fig. 3, of the combination 20 according to the invention. As shown in Fig. 8, all the electrical cables 31 for the piezo elements of the combinations 20 can again be connected to a common alternating voltage generator 50.
Instead of a cut line, such a tool part 100 can naturally also make a welded seam between two or more webs Iying on top of one another. Furthermore, the tool part 100 could also have any desired shape and carry out other functions, such as serving as an atomiser for liquids or the like. In this case 30 the atomiser would be configured in the form of a plate onto which several combinations 20 according to the invention are fixed and during operation jointly excite the plate to cause ultrasound vibrations. A liquid landing on this plate would then be atomised by these vibrations. By using a large number of combinations 20 a correspondingly high degree of vibrational energy would be produced on the plate or the tool part 100, which would then be used.

Claims

1. An appliance for ultrasonic cutting and/or ultrasonic welding of web materials (10), preferably such consisting of fusible materials, particularly of broadloom fabrics (10) woven from threads, driven by an alternating-voltage electric generator (50).

having an oscillation transducer (24') consisting of three coaxial segments [(21'), (22'), and (23')], namely such having a piezoelectric element (21') sandwiched between a transmitting segment (23') having a high acoustic transmittance and a backing segment (22') having low acoustic losses, that accepts alternating voltages supplied by said electric generator (50) and transforms same into acoustic energy located at the center of its oscillation transducer (24'), equipped with a horn radiator (26) that concentrates the amplitudes of ultrasonic energy coming from said oscillation transducer (24') and whose tip (28') contacts said web material (10) and transfers said ultrasonic energy to said web material (10), and having an anvil (30) on the reverse side (17) of said web material (10), characterized by the fact that instead of said transmitting segment (23'), said horn radiator (26) is seated directly on said piezoelectric element (21) and is fastened to a backing segment (23) on the opposite side of same by a bolt (48), forming a horn-piezoelectric element-backing segment assembly (20), where the axial length (32) of said backing segment (22) is less than, or equal to, 1/8 of the effective acoustic wavelength, .lambda., while the overall axial length (38) of said assembly (20) is less than, or equal to, 3/4 of the acoustic wavelength, .lambda., and that said piezoelectric elements (21) of several, independent, cutting and/or welding, assemblies (20) are simultaneously driven by a single generator (50) (Figs.
1 and 8).

2. An appliance per Claim 1, characterized by the fact that the overall axial length (38) of said assembly (20) is less than, or equal to, half the acoustic wavelength, .lambda..

3. An appliance per Claims 1 or 2, characterized by the fact that the axial length (32) of said backing agent (22) of said assembly (20) is less than, or equal to, 1/8 of the acoustic wavelength, .lambda..

4. An appliance per one or more of Claims 1 through 3, characterized by the fact that its tapered horn radiator (26) is fabricated from a light alloy, while the tip (41) of said horn radiator is fabricated from steel having an intrinsic hardness in excess of HRC 60.

5. An appliance per Claim 4, characterized by the fact that a spacer (42) fabricated from a material having a elastic modulus is interposed between said tapered horn radiator (26) and said tip (41) of said horn radiator.

6. An appliance per one or more of Claims 1 through 5, characterized by the fact that said assemblies (20) are arrayed along a single way (57) traversing the web material (10) to be cut into strips (15) or welded.

7. An appliance per Claim 6, characterized by the fact that it incorporates a bilateral guiderail structure (58) having said assemblies (20) mounted, or alternately mounted, on both opposing rails [(88) and (88')] of saidbilateral guiderail structure (cf. Fig. 6).

8. An appliance per Claim 6 or Claim 7, characterized by the fact that all assemblies (20) mounted on said way (52) or said bilateral guide-rail structure (58) share a single continuous bar (53) on the reverse side (17) of said web material that serves as a passive anvil (30).

9. An appliance per Claim 8, characterized by the fact that said bar consists of a hollow tube (53) filled with a ductile material (102), such as lead, having a high mass density.

10. An appliance per one or more of Claims 1 through 9, characterized by the fact that each such assembly (20) is installed in a housing (60) that may be clamped onto said way (52) or said bilateral guiderail structure (58) (cf. Fig. 7).

11. An appliance per Claim 10, characterized by the fact that said way (52) or said bilateral guiderail structure (58) is equipped with a longitudinal toothed rack (57), and that said housings (60) holding said assemblies (20) have through holes (78) extending to said toothed rack (57) into which an adjusting tool (80) having splines (81) may be inserted in order to alter the lateral positionings of said assemblies (20) (cf. Fig. 7).

12. An appliance per Claim 11, characterized by the fact that said housings (60) holding said assemblies (20) have self-actuating detents (82) that attempt to engage the teeth of said toothed rack (57), or to become disengaged from same when said adjustingtool (80) is inserted into said through holes (78) (cf. Fig. 7).

13. An appliance per one or more of Claims 1 through 12, characterized by the fact that said assembly (20), or an array of such assemblies (20), is continuously driven by said alternating-voltage generator (50).

14. An appliance per one or more of Claims 1 through 13, characterized by the fact that several such assemblies (20) share the same tool component (100) instead of each having its own horn tip (41), that their piezoelectric elements (21) are connected in parallel to the same alternating-voltage generator (50), and that said shared tool component (100) has a blade (101) profiled to suit the slits to be cut, or the seams to be welded, in web materials (10) (cf. Fig. 8).

15. An appliance per Claim 14, characterized by the fact that said shared tool component (100) is employed for atomizing liquids or similar.