Ultrasonic vibration system having a lateral surface mounting

Abstract

The present invention concerns an ultrasonic vibration system comprising a sonotrode which has two sonotrode end faces and a circumferentially extending lateral surface connecting the two sonotrode end faces together, wherein the sonotrode has an elongate core element and at least one wing element, wherein core element and wing element respectively extend from the one sonotrode end face to the other sonotrode end face in a longitudinal direction, wherein the wing element has a sealing surface which is provided to come into contact with a material for processing thereof and is connected to the core element by way of a plurality of webs spaced from each other in the longitudinal direction of the core element, and a converter which is optionally connected to the sonotrode by way of an amplitude transformer. According to the invention it is proposed that the ultrasonic vibration system is connected to a machine stand by way of a mounting connected to the lateral surface.

Claims

1. An ultrasonic vibration system comprising a sonotrode which has two sonotrode end faces (8, 8′) and a circumferentially extending lateral surface connecting the two sonotrode end faces (8, 8′) together, wherein the sonotrode has an elongate core element (2) and at least one wing element (3, 4), wherein core element (2) and wing element (3, 4) respectively extend from the one sonotrode end face (8, 8′) to the other sonotrode end face (8, 8′) in a longitudinal direction, wherein the wing element (3) has a sealing surface (7) which is provided to come into contact with a material for processing thereof and is connected to the core element (2) by way of a plurality of webs (5, 6) spaced from each other in the longitudinal direction, and a converter which is optionally connected to the sonotrode by way of an amplitude transformer (11), wherein the ultrasonic vibration system is connected to a machine stand by way of a mounting connected to the lateral surface, characterised in that the mounting has a material-bonded joint comprising a first joint member and a second joint member which are connected together by way of a flexible element (17).

2. An ultrasonic vibration system according to claim 1 characterised in that the sonotrode has two wing elements (3, 4) which are respectively connected to the core element (2) by way of a plurality of webs (5, 6) spaced from each other in the longitudinal direction of the core element (2).

3. An ultrasonic vibration system according to claim 2 characterised in that the one of the wing elements (4) is the first joint member.

4. An ultrasonic vibration system according to claim 3 characterised in that the flexible element (17) is fixed to the first joint member (4).

5. An ultrasonic vibration system according to claim 4 characterised in that the flexible element (17) engages in a region of the first joint member (4), which lies within a notional prolongation of one of the webs (5, 6) in the direction of the first joint member (4).

6. An ultrasonic vibration system according to claim 1 characterised in that the flexible element (17) is of a length of between 8 and 25 mm.

7. An ultrasonic vibration system according to claim 1 characterised in that the width b.sub.Flex of the flexible elements (17) in the direction of the length L is less than the width b.sub.S of the webs.

8. An ultrasonic vibration system according to claim 1 characterised in that the ultrasound vibration unit is connected to a machine stand by way of at least two material-bonded joints connected to the lateral surface.

9. An ultrasonic vibration system according to claim 1 characterised in that there is provided a converter which is connected to the lateral surface of the sonotrode by way of the amplitude transformer.

10. An ultrasonic vibration system according to claim 1 characterised in that the webs (5, 6) are formed between through openings in the lateral surface, wherein the through openings are elongate and the longitudinal direction thereof extends from the core element (2) to the wing element (3, 4).

11. An ultrasonic vibration system according to claim 1 characterised in that the wing element (3, 4) is of a thickness less than the thickness of the core element (2).

12. An ultrasonic vibration system according to claim 1 characterised in that the wing element (3, 4) is of a width less than the width of the core element (2).

13. An ultrasonic vibration system according to claim 2 wherein the two wing elements (3, 4) and the core element (2) are disposed in one plane.

14. An ultrasonic vibration system according to claim 6 characterised in that the flexible element (17) is of a length of between 10 and 15 mm.

15. An ultrasonic vibration system according to claim 7 wherein the flexible elements are of a width b.sub.Flex which is between 5 and 90% of the web width b.sub.S.

16. An ultrasonic vibration system according to claim 15 wherein the flexible elements are of a width b.sub.Flex which is between 20 and 60% of the web width b.sub.S.

17. An ultrasonic vibration system according to claim 8 characterised in that the ultrasound vibration unit is connected to a machine stand by way of three material-bonded joints connected to the lateral surface.

18. An ultrasonic vibration system according to claim 11, wherein the thickness of the wing element is less than 75% of the thickness of the core element.

19. An ultrasonic vibration system according to claim 12 wherein the width of the wing element is less than 50% of the width of the core element.

Description

(1) Further advantages, features and possible uses of the present invention will be apparent from the description hereinafter of two embodiments of the invention and the accompanying Figures in which:

(2) FIG. 1 shows a plan view of a first embodiment of an ultrasonic vibration unit according to the invention,

(3) FIG. 2 shows a perspective view of the embodiment of FIG. 2,

(4) FIG. 3 shows a side view of the embodiment of FIG. 1,

(5) FIG. 4 shows a plan view of a second embodiment of the invention, and

(6) FIG. 5 shows a perspective view of the embodiment of FIG. 4.

(7) FIG. 1 shows a first embodiment of an ultrasonic vibration system 1. FIG. 2 shows a perspective view of that embodiment while FIG. 3 shows a side view.

(8) The ultrasonic vibration system 1 comprises a sonotrode which in turn has a core element 2 and two wing elements 3, 4. The wing elements 3, 4 are connected to the core element 2 by way of suitable webs 5, 6. Both the core element 2 and also the wing elements 3, 4 extend in the longitudinal direction L. The sonotrode has a series of through openings which are so arranged that the webs 5, 6 are formed between the openings.

(9) It will be seen from FIG. 2 that the core element 2 is of a greater thickness (in the direction D) than the two wing elements 3, 4. Likewise the core element 2 is of a width b.sub.K (in the direction B) greater than the width b.sub.F of the wing elements. The core element 2 is of an elongate configuration and together with the wing elements 3, 4 and the connecting webs 5, 6 has two end faces which are connected together by way of a circumferentially extending lateral surface. The lateral surface can be clearly seen in FIG. 1 while FIG. 3 shows a view on to one of the two end faces 8, 8′. The end face 8, 8′ of the sonotrode has two bevel surfaces 8.

(10) A wing element 3 has a sealing surface 7 which is intended to come into contact with the material to be processed. In operation that sealing surface is intended to perform an in-plane vibration which is as homogeneous as possible and the direction of which is diagrammatically shown in FIG. 2 by means of a double-headed arrow.

(11) To permit such in-plane vibration of the sealing surface 7 the ultrasonic vibration unit 1 has to be excited. In the illustrated embodiment the core element is caused to perform an ultrasonic vibration which is transmitted by means of the webs 5, 6 to the wing elements and in particular to the sealing surface 7. A converter 9 having suitable piezoelectric elements 10 is used for excitation purposes, the elements 10 converting an electric ac voltage into a longitudinal mechanical ultrasonic vibration. That is transmitted to the amplitude transformer 11 which here is of a similar structure to the sonotrode, more specifically comprising an amplitude transformer core element 12, amplitude transformer wing elements 13, 14 and connecting webs 15 which connect the amplitude transformer core element 12 to the amplitude transformer wing elements 13, 14.

(12) By virtue of the converter 9 being coupled to the amplitude transformer 11 the amplitude transformer core element 12 is caused to perform an in-plane vibration which is transmitted by way of the connecting webs 15 to the amplitude transformer wing elements 13, 14. As the amplitude transformer wing element 14 is connected to the core element 2 of the sonotrode the vibration is transmitted to the sonotrode and thus to the sealing surface 7. As a result this gives a very compact structure for an ultrasonic vibration unit 1.

(13) In order to influence the vibration amplitude as little as possible a mounting is provided at the side of the sonotrode that is remote from the sealing surface 7, that is to say at the wing element 4, the mounting being formed from a fixing beam 16 which can be fixedly connected to a machine stand. and corresponding flexible elements 17. Bores for fixing the fixing beam 16 to the machine stand can be arranged in the fixing beam 16. In that case the wing element 4, the flexible elements 17 and the fixing beam 16 form rigid-body joints. The flexible elements 17 are of a length of about 14 mm in the direction B. The flexible elements 17 are formed by elements in blade form, which are of a markedly smaller dimension in the longitudinal direction L than in the two directions B and D perpendicular thereto. The result of this is that the flexible elements are of a much greater flexibility in the longitudinal direction L than in the directions perpendicular thereto. That measure permits reliable mounting of the sonotrode even when a welding force is being applied to the sealing surface while at the same time the in-plane vibration of the wing element 4 is only slightly influenced by virtue of the flexible elements.

(14) It can be seen from FIG. 1 that all flexible elements 17 engage the wing element at least in part in the region of a projection of the webs on to the wing element 4. The projections are shown as a broken line in FIG. 1. The flexible elements are therefore not arranged ‘above’ the through openings but ‘above’ the webs.

(15) In the illustrated example the wing element 3 is connected to the core element 2 by way of a total of nine webs 5, 6. It will be seen that the end faces respectively have a bevel surface at both sides in the direction of the wing elements whereby the width of the outer webs 6 is reduced. By virtue of that measure the vibration performance of the sonotrode can be improved.

(16) In addition the width b.sub.Flex of the flexible elements in the direction of the length L is less than the width b.sub.S of the webs. The term width b.sub.S, in the case of a width which is not constant, is used to denote the minimum width, as shown in FIG. 1. Likewise the term width b.sub.Flex is used for the case of a width of the flexible element that is not constant, to denote the minimum width of the flexible element.

(17) FIGS. 4 and 5 show a second embodiment of the invention. In this case the sonotrode is constructed in the same manner as the embodiment shown in FIGS. 1 to 3. The sole difference here is that another amplitude transformer is used. This substantially comprises a curved element 11′ which converts the longitudinal ultrasonic vibration generated by the converter 9 by means of the piezoelectric discs 10 into an in-plane vibration. The curved amplitude transformer 11′ is then again connected to the core element 2 of the sonotrode.

(18) The mounting can be as in the embodiment shown in FIGS. 1 to 3. The mounting however is not illustrated in FIGS. 4 and 5.

LIST OF REFERENCES

(19) 1 ultrasonic vibration system/ultrasonic vibration unit 2 core element 3 wing element 4 wing element 5 web 6 web 7 sealing surface 8, 8′ end face 9 converter 10 piezoelectric element 11 amplitude transformer 11′ curved element 12 amplitude transformer core element 13 amplitude transformer wing element 14 amplitude transformer wing element 15 connecting webs 16 fixing beam 17 flexible elements