MXPA97002081A - Piston ultrason converter - Google Patents

Abstract

An assembly of ultrasonic transducer (20) for hygienic ultrasonic sealing is described. The assembly includes an ultrasonic, hygienic sealing area, and an unhygienic area, separated by a barrier wall (88). The barrier wall has an opening that allows an ultrasonic converter (186) to move back and forth ("in alternating motion") through the opening. The ultrasonic converter (186) is also vibrated at an ultrasonic frequency by the machinery located in the unhygienic area of the machine, and transmits those vibrations to the hygienic area of the machine. The converter has a null area (92) in which the converter is vibrated substantially in the same manner, and other areas that are vibrated much more vigorously. A generally cylindrical sealing surface (194) is fixed with respect to the null area of the transducer. The sealing surface is fronted or cleaned by a rubbing seal (202) mounted on the edge of the opening. These two parts can also be inverted

Description

ULTRASONIC PISTON CONVERTER CAMPü TECNiCü The present invention relates generally to an ultrasonic sealing or welding machine for hygienically bonding heat-sealable surfaces, and more particularly to a machine of this type having an arrangement for the isolation of hygienic areas where a clean product (such as as food) is exposed to non-hygienic areas where the machinery is located.

BACKGROUND OF THE INVENTION The machinery for packaging food, pharmaceutical products, or other products that must be handled in a hygienic manner is well known. Typically, such machinery has certain parts, such as gears, motors, bearings, etc., which must be present to provide a work machine and must not be exposed to the product that is hygienically packaged. Typically, these are mobile elements of the machine which are difficult to clean. Commonly, it is also REF: 24316 desirable to prevent contamination of non-hygienic areas with the hygienic product. A barrier must be maintained between the hygienic areas and the non-hygienic areas of the machine to meet these goals. The task of designing an appropriate barrier is more complicated when the machine has moving parts which regularly move back and forth between the hygienic and non-hygienic areas (as is commonly the case). In this situation, the barrier between the hygienic and non-hygienic areas of the machine has included seals, folding bellows or other elements to maintain the insulation between the hygienic and non-hygienic areas along the portions of the machinery that pass through. the barrier . An even more difficult situation arises when the ultrasonic energy is transmitted from a generator in the unhygienic area of the machine to the hygienic area, through a barrier between the respective areas. Simply by providing a seal that sweeps an ultrasonic transducer projecting through a barrier wall will not suffice: the ultrasonic energy carried by the transducer can damage the seal quickly and break the barrier. Other resources, such as a bellows seal between the moving parts, can also be damaged when one of the parts becomes ultrasonic energy. A bellows seal exposed to the hygienic area is also difficult to keep clean or to inspect for integrity, and thus may be unsatisfactory for use in the hygienic area of a machine.

BRIEF DESCRIPTION OF THE INVENTION An ultrasonic transducer assembly is claimed for hygienic ultrasonic sealing. The assembly includes a hygienic sealing area that must be kept clean to protect the exposed food and an unhygienic area where the food will not be exposed. These areas are separated by a barrier wall. The barrier wall has an opening that allows an ultrasonic converter to move back and forth ("move in alternating motion") through the opening. The ultrasonic converter is vibrated at an ultrasonic frequency by machinery located in the non-hygienic area of the machine, and transmits those vibrations to the hygienic area of the machine. The converter has a null area in which the converter is vibrated substantially minimally and other areas that vibrate much more vigorously. A sealing surface in general cylindrical is fixed with respect to a first member. The first member may be either the edge of the hole through the barrier wall or the null area of the transducer. The sealing surface faces a second member which is the edge of the hole, if the first member is the null area or vice versa. A seal is mounted to the second member. The seal rubs or cleans the sealing surface in general cylindrical as the converter is moved forward and backward. A characteristic of the present machine is that only the null area of the transducer is in contact with the barrier, even if the null area moves with the transducer, so that it is not in a fixed place in relation to the barrier. Very little ultrasonic energy is transmitted through the null area, so that the barrier is very isolated from the ultrasonic energy transmitted through it. In this way, the ultrasonic energy has little or no effect on the integrity of the barrier.

Another feature of the present machine is that it is easy to clean, since complex surfaces (such as the wall of a folding bellows conduit) are not required to maintain a barrier.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a cardboard sealing machine.

Figure 2 is a side elevation view of the machine of Figure 1, with some portions shown in section and other portions removed.

Figure 3 is a side elevational view taken from line 3-3 of Figure 1, with the top or cover structure removed for clarity.

Fig. 4 is a fragmentary, perspective, detail view of the draw bar, drive rod, and pneumatic deflection member of the anvil drive assembly, with a portion cut away to reveal the interior details of the driver element; deviation.

Figure 5 is a partial section of the biasing element, taken along line 5-5 of Figure 4.

Figure 6 is a schematic elevation view, taken from the perspective of the sectional line 6-6 of Figure 1, of an anvil and the sealing horn limiting in a sealing position by closure.

Figure 7 is a view similar to Figure 6, showing the anvil and the sealing horn in their open positions, with a pinion lock positioned between them in a sealing position by closure.

Figure 8 is a view similar to Figure 7, showing the anvil and the sealing horn in their closed positions, respectively, resting against the pinion closure.

Figure 9 is a section taken along line 9-9 of Figure 1, showing how the hygienic and non-hygienic areas of the present machine are kept separate, where the ultrasonic sealant penetrates the insulation wall.

Figure 10 is a more detailed perspective view, in isolation, of the anvil bar to Figure 1.

Figure 11 is a section, taken parallel to one of its main side faces, of one of the anvils shown in Figure 10.

Figures 12, 13 and 14 respectively, are graphs of the acceleration, speed and position of the cam drive according to the embodiment of Figures 1-11, each versus time, for sealing or sealing the upper seal of a compact upper cardboard box in pinion.

Figures 15-17 are similar to the Figures 12-14, showing the acceleration, the speed and the position of the cam drive for sealing the lower seal of a bottom cardboard box in pinion. DETAILED DESCRIPTION OF THE PREFERRED MODALITY While one or more preferred embodiments will be described, it will be understood that the claims are not limited to those embodiments. On the contrary, the claims will be interpreted to include all alternatives, modifications, and equivalents within their spirit and scope. Referring first to Figure 1, the carton sealer generally indicated at 20 is a module of a carton filling and sealing machine, such as that described in U.S.S.N. 08 / 190,546, filed on February 2, 1994, which is incorporated by reference herein (the other parts of which are not shown). A filling and sealing machine of this type includes two such modules, one for sealing the lower flap 22 (shown in Figure 2) of each carton such as 24, before it is filled, and the other for the sealing the upper flap of the carton 24 (which will be placed in the fold line 26 shown in Figure 2, after the top closure is folded). The upper flap 26 is sealed after the carton is filled.

Each closure 22, 26 of the carton 24 has a first side 28 which faces the anvils such as 32 and a second side 30 which faces the tips of the ultrasonic sealing anvil, such as 34, when the carton 24, and more particularly a closure such as 22 of the carton 24, is placed in a sealing position by closure. A typical closure that can be sealed according to the present machine is a top or bottom pinion closure for a food carton box. Referring briefly to Figure 2, the carton 24 is sealed according to the following sequence. First, the carton 20, which has been previously folded substantially to its final configuration by the apparatus which is not illustrated here, is advanced, moving its lower flap 22 from a position in which it is free of the sealer 20 cardboard boxes to the closing sealing position. The lower flap is then sealed by closing the anvil 32 and the sealing horn 34, substantially together to embrace the closure 22, as also illustrated in Figure 8. The sealing horn heats the lower flap 22, fusing together its elements are heat-sensitive. The closure 22 is then released.

After the anvil 32 and the sealing horn 34 are separated, the lower flap 22 is translated in the reverse direction to uncouple the carton 24 from the carton sealer 20, allowing the carton 24 to be advanced towards the filler (not shown).

Main Sealant Element Returning now to Figure 1, the sealant , which is an embodiment of the present machine, includes an anvil 32, a tip 34 of the ultrasonic sealing anvil, an anvil drive generally indicated at 3"a horn drive generally indicated at 38, and the elements of deviation 40 and 41.

Anvil assembly In the illustrated embodiment, a series of eight anvils is provided: 32 and 42-54, so that eight cartons can be sealed at the same time with a simple reciprocal stroke or stroke of the anvils assembled together. The eight anvils 32 and 42-54 are mounted on an anvil bar 56. The anvil bar 56 is arranged to travel back and forth reciprocally, reciprocatingly moving each anvil such as 32 back and forth between an open position (better shown in Figures 1 and 7) allowing a cardboard box to pass and a closed position (best shown in Figure 8) for leaning against the first side 28 of a closure (such as the lower flap 22) located in the closing sealing position. An anvil, rectangular frame 58 is defined by the anvil bar 56, the driving rods 60 and 62, and a drag bar 64. The driving rods 60 and 62 are rigidly bolted to the feet 66 and 68 of the anvil bar 56. The details of the fastening in this embodiment are best seen in Figure 2. The pull rods 60 and 62 are operatively connected to the drawbar 64 by the diverting elements 40 and 41. The details of this connection are provided below. . The pull rod 60 is supported by the reciprocal travel with respect to the frame 70 of the carton sealer 20 by the sliding bearings 72 and 74 (which are prominent in Figure 2), while the pull rod 62 is supported by the reciprocal travel with respect to the frame 70 of the carton sealer 20 by the slide bearings 76 and 78. With reference to Figures 1 and 2, the slide bearings 72 and 76 may be identical. Each is defined by a bush with bushing such as 80, which is integral with the frame 70, and has a generally cylindrical bore 82 terminated at their respective ends by retaining rings 84 and 86. A slip ring 84 is fixed to an associated driving rod, such as 62 and slidable between the limits defined by the retaining rings 84 and 86 within the hole 82. The retaining rings 84 and 86 of this embodiment are also rubbing or cleaning seals which help isolating the unhygienic area, generally to the right (in Figure 2) of the insulation wall 88, where the drive machine is located, from the sanitary area in general to the left of the insulation wall 88, where the cardboard boxes are being filled and packed. This resource is desirable because the pull rods 60 and 62 move alternately through the bushing 80. By providing seals on each end of the bore 82, the successive alternating movements of the pull rods will not tend to make advance lubricants or other foreign material to or through holes such as 82 from right to left (as shown in Figure 2). It is also important to prevent foreign material, such as spilled food or cardboard waste, moving from left to right, as shown in Figure 2, in and through holes such as 82. That goal is also achieved by the illustrated modality. In this embodiment, the sliding bearings 74 and 78 are located completely within the unhygienic area to the right of the isolation wall 88 of Figure 2, and a second pair of retaining rings 84 and 86 could be redundant. In this way, the ordinary sliding bearings 74 and 78, which lack rubbing seals will be sufficient to maintain the travel of the axially exact driving rods 60 and 62 along the shafts of the driving rods.

Anvil drive An anvil drive generally indicated at 36 is provided for the movement of the drawbar 64, and thus the bar 56 of the anvil and the coupled anvils 32 and 42-54, back and forth between their respective open positions. and closed. The drive for advancing the anvils 32 and 42-54 towards their closed positions, acts on one side generally facing the horn, of the frame 48 of the anvil, and in this mode acts specifically on the side 90 facing the horn , of the drag bar 64. The side facing the horn, of the drag bar 64, has advancing cam rollers, here the rollers 92 and 93, and retraction cam rollers, here the rollers 94 and 95 (95 is shown mainly in broken line in Figure 3) attached to it, which are actuated by the cams 96 and 98. Since the two cam drives are identical, only one will be described in detail. The cam 98 has an anvil advancement surface 100 for movement of the anvils towards its closed position, and an anvil retraction surface 102, better seen in Figures 2 and 3, for the movement of the anvils towards their open position . The cams 96 and 98 are respectively mounted rotatably on the pivots. Here, the axes 104 and 106 of the cam (which may alternatively be the respective ends of a single axis) carried in the rotation bearings (not shown) define those pivots. The cam shafts 104 and 106 are driven by a servomotor 108 by means of a gear train located within the gearbox 110 for rotation of the cams 96 and 98 about their pivots. The servomotor or the gear train can be used to vary the speed of rotation of the cam at various points in its travel, in relation to the surface profile of the cam, so that the required amount of torque of the servomotor does not exceed its capacity , particularly where the change in the radius of the cam is gradual. The sealing profile of the cam position, speed, and acceleration can also be changed remotely as desired, by changing the position, speed and acceleration profile of the servomotor. Typical profiles are described below in connection with Figures 12-17. The cam 98 shown in Figures 2 and 3 is in its initial position in which the anvils 32 and 42-56 are in their fully open positions. The cam 98 is first driven clockwise about 160 degrees by the servo motor 108, so that the radius of the portion of the surface 100 of the cam that rests on the cam roller 94 is generally increased. With reference to Figure 1, that movement of the cam 98 pushes the cam roller 94, and thus the draw bar 64, the driving rods 60 and 62, and the anvil bar 56, with upward direction toward their respective closed positions. Subsequently, when a seal is completed and the anvils 32 and 42-54 are to be retracted to their open position, the cam 98 is driven counterclockwise to its initial position. The retraction surface 102 of the anvil of the cam 98 strikes the cam roller 95, with the radius of the portion of the cam surface 102 contacting the cam roller 95 generally decreasing. This counter-rotation of the cam 98 pulls the draw bar 64, the draw rods 60 and 62, and the anvil bar 56 with downward direction (as shown in Figure 1) toward their open positions.

Ultrasonic Anvil Tip Assembly In the illustrated embodiment, a series of four anvil tips or ultrasonic seal transducers-34 and 112-116-are provided, each one wide enough to be supported against two anvils, so that eight cartons can be sealed at the same time. time with a simple reciprocating stroke of the sealing anvil tips assembled together. The sealing anvil tips 34 and 112-114 are mounted on a frame or support 118. The frame or support 118 is arranged to travel back and forth reciprocally between an open position (best shown in Figures 1 and 7) that allows a cardboard box to pass, and a closed position (best shown in Figure 8) for leaning against the second side 30 of a closure (such as the lower flap 22) located in the closing sealing position. The frame or support 118 has bushings with bushing, integrals 120 and 122 slidably received on the driving rods 60 and 62, defining sliding bearings. This arrangement accurately positions the anvil tips and the anvils relative to each other, as they move alternately. Ultrasonic stacks terminating at the sealing anvil tips 34, 112, 114 and 116 also include ultrasonic transducers or transducers and ultrasonic generators, which are not shown. The batteries or ultrasonic blocks are shown on the support 118 to place, support and actuate them.

Horn drive Ultrasonic A cam-operated horn drive, generally indicated at 38, is provided for movement of the support or frame 118 back and forth between its open position and its closed position. The cams 96 and 98 each have a horn drive cam surface, such as the surface 124 shown in Fig. 2, and a horn retraction cam surface, such as the surface 126 shown in Fig. 2. These surfaces Levers are substantially opposite to, but approximately in the same shape as, the anvil and retraction actuation surfaces, so that the anvils and the sealing horns move in position when the cams are rotated. The cams 96 and 98 respectively drive the cam rollers 128 and 130, which are coupled to the support or frame 118, and follow the outer surfaces 124 of the cooking drive of the cams 96 and 98. In this way, the rotation in favor of the clock hands of the cams 96 and 98 as described above, generally increases the radius tracked or traced by the cam rollers 128 and 130, driving the support 118 and the sealing horns 34 and 112-116 in the direction of down (as shown in Figure 1) to its closed position. The cams 96 and 98 respectively drive the cam rollers 132 and 134, which are attached to the support 118 and follow the interior horn retraction surfaces 126 of the cams. In this way, the counterclockwise rotation of the cams 96 and 98 as described above, generally decreases the radius tracked or traced by the cam followers 132 and 134, driving the support 118 and the sealing horns 34 and 112-116 upwards (as shown in Figure 1) to its open position. A feature of the present machine is in this way that the anvil and the sealing horn are movable in coordination by the same cams, thus using the same acceleration, speed and position profiles, so that a closure located in the center of a cardboard box can be coupled without the movement of the cardboard box laterally. Neither the sealing horn nor the anvil will arrive early or late, since both are operated in cooperation. In this way, the carton can be safely supported in such a way that it is not laterally movable, since the position in the carton need not be adjusted to take into account the displacements in the closed position of the cartons. horns and anvils. Yet another advantage of the illustrated arrangement is that the anvil drive and the horn drive are positioned on the same side of the sealing area, rather than on opposite sides. Thus, an insulation wall 88 is necessary only on one side of the sealing area, so that the sealing operation can be easily inspected from that side of the machine, while the operation of the non-hygienic part of the machine It can be observed from the other side of the simple insulation wall. The sealing apparatus, which is all placed in one area and which employs multifunctional cams, also has a minimum width, which is desirable to minimize the width of the sealing line.

Deviation Element The deflecting element 40 - which can be designed as a cushion or spring - is connected either between the anvil or the horn and its actuator (or between each of these elements and its actuator, in the alternative mode). The biasing element limits the sealing pressure developed between the anvil and the horn to a predetermined maximum value. The default value is the pressure exerted by the deflection element. This prevents the anvil and the horn from holding the latch too tightly and thus damaging the seal or sealing machine, and compensates for slight inaccuracies in the position of the anvil or horn without increasing or decreasing the sealing force. The deviation force can also be remotely adjusted, without stopping the machine, by using an externally applied pneumatic force as the deviation element. In the present embodiment, the diverting elements 40 and 41 operatively connect the anvils such as 32 to their cam actuator. With reference to Figures 4 and 5, the biasing elements 40 and 41 are identical pneumatic unions. Springs or other elastic couplings can also be used, although pneumatic couplings have certain advantages, which will be described later. For brevity, only the biasing element 40 will be described here. The biasing member 40 comprises a hole 140 which receives a sliding piston 142. The annular cylinder and the surfaces of the piston 144 and 146 and the orifice 140 define a space 148. substantially closed. The piston 142 is captured on the end of the driving rod 62 by the nuts 150 and 152 screwed onto the extension 154 of the driving rod 62. The hole 140 is formed in an integral part of the driving rod 64. The space 148 is pressurized via a gate 156 and a pressure regulator 158 with a source of pressurized gas 160. A remote control such as 162 can be used to change the preset or desired pressure value of the regulator 158, thereby changing the pressure within the space 148. The pressure of the gas within the space 148 deflects the surface 146 of the piston to the right relative to the surface 144 of the cylinder, so that the piston floats above or above the surface 144, thereby deflecting the rod of drag 62 and the anvil bar 56 to their respective closed positions. The degree to which the piston 142 floats above the surface 144 of the cylinder can be controlled by the capture of the piston 142. In the embodiment of Figure 5, the flange 164 of the piston 142 captures the piston 142 within the bore 140 of the piston 142. cylinder When the drag bar 64 and the anvils such as 32 are in their closed positions, the closure of the cardboard box that is sealed is pushed by the anvils, keeping the flange 164 out of its stop. At this point, the gas cushion in the space 148 is the only force exerted by the anvil against the closure and the opposite sealing horn. This sealing force is the product of the gas pressure between the space 148 and the effective area of the surface 144. A specific force of about 15,000 N is contemplated in this embodiment, although greater or lesser pressure may be desirable in given situations. An advantage of the illustrated arrangement is that the sealing force exerted by the anvils 32 is reproducible, despite minor differences in the thickness or elasticity of the fins such as 22 (due, for example, to the occasional capture of small quantities of product within the fin creases 22). Another advantage is that, being equal to the pressure of the gas within the space 148, the pressure of the anvil can be changed by changing the pressure of the gas. The gas pressure can easily be changed remotely. Yet another advantage of the present arrangement can be realized by allowing communication between the respective space 148 of two or more deviation elements such as 40 and 41. This allows reliably identical deviation pressures to be exerted at all times by two elements of deviation connected to the same driving rods 62 or to other elements of the machine. Such communication is schematically illustrated in Figure 1.

Ultrasonic Converter Seal Referring now to Figures 1 and 9, there is shown an arrangement for sealing between the ultrasonic vibration converter 186 and the insulation wall 88, which divides the unhygienic area (to the left of the wall 88 in Figure 9). ) of the hygienic area (to the right of the wall 88 in Figure 9). This area must be sealed because the converter 186, which is attached to the sealing horn 112, also moves alternately between the open and closed positions as the support 118 moves. It is important to prevent the foreign material from being impelled or forced in any way through the insulation wall 88, by the alternating movement and vibration of the converter 186. The necessary barrier is obtained as illustrated in Figure 9. The wall of The insulation 88 has an opening defined by a marginal edge 188. An ultrasonic converter 188 is placed in the opening 188, and reciprocates within the opening 188 along an axis 190 that passes through the opening. The converter 188 is vibrated at an ultrasonic frequency by the machinery placed in the non-hygienic area. The converter 186 has a null area or nodule 92 in which the converter is vibrated, substantially minimally. (The ultrasonic waves are waves at rest propagated along the axis 190, so that the converter 186 has one or more nodes, each placed substantially in a plane perpendicular to the axis 190, where the local amplitude of the vibrations is very small in relation to its maximum amplitude). A sealing surface 194 generally cylindrical, defined by a sleeve or sleeve 196 is fixed with respect to a first member, which is one of the marginal edge and the null area. Here, the sleeve 196 is fixed to a skirt 198 projecting forward, which depends on the null area 192. The skirt projects effectively ahead of the null area, which is important so that the converter does not transmit substantial ultrasonic energy. towards the sleeve 196, which could damage or melt the seal described later. The sealing surface 194 faces a second member, which is the other of the marginal edge and the null area (and here is the marginal edge 188 defining the opening in the wall 88).

The beam or web 200 of the sleeve 196 is joined, either by welding, to the skirt 198. The beam 200 defines a barrier between the sealing surface 194 and the null area 192, which prevents the foreign material from passing through. the jacket 196. The seal between the converter 186 and the opening 188 is completed by a cleaning or rubbing seal 202 mounted to the opening 188, which rubs or cleans the sealing surface 194 in general cylindrical, as the converter 186 is moved alternately It will be appreciated that the parts of the assembly can be rearranged. For example, the seal 202 can be mounted to the null area 192 and the sleeve can be mounted to the opening 188 to obtain the same effect.

Anvil adjustment Figures 1, 10 and 11 show certain advantageous details of the anvils 32 and 42-54, and their assembly on the bar 56 of the anvil. Each anvil is identically connected, so that only the anvil 32 and its assembly will be described. The anvil 32 is received by a reinforcing element - here, the anvil bar 56 that extends substantially perpendicular to the axis 210 - which is adapted to move generally along the axis 210 between an open position and a position closed relative to the transducer or sealing horn 34 (shown in Figure 7), as previously described. The anvil bar has a flat mounting surface 208, to which the anvils such as 32 are bolted. The anvil bar 56 has a cylindrically curved front surface 212, which is opposite the corresponding transducer 34, and defines an arc. of a circle that has a center of curvature 214 and that generally falls in a plane (here, the plane of the paper for Figure 11) defined by the axis 210. This plane is chosen because there is a need to pivotally adjust the anvil 32 in that plane. The circle that defines the adjustment plane can also fall in a plane that intersects the plane of the paper in Figure 11, if adjustments are desired in other planes. Alternatively, the curved surface 212 may be a spherically curved surface which could allow universal adjustment of the orientation of the anvil 32 about the center 214. The surface 212 is shown as a concave surface, but this could also be a convex surface.

With particular reference to Figure 11, the anvil assembly 32 includes an anvil pad or seat 216, a front member 218, an elastic seat 220, and pipe couplers 222 and 224, which are all bonded together in a manner appropriate The clamping screws 226 and 228 are received in the clamping holes 230 and 232 to normally tighten the anvil assembly 32 to the mounting surface 208. The anvil assembly 32 has a front surface 234, of complex shape, best shown in FIG. Figures 7 and 8, for contacting a workpiece and a curved back surface 236, which is substantially complementary and normally rests against the curved front surface 212. As used in this description, a "complementary" pair of surfaces, are a convex and concave surface, which have substantially a common center of curvature and define circles that fall in the same plane. The fastening holes 230 and 232 are substantially larger than the shafts of the fastening screws 226 and 228 they receive, but smaller than the heads of the fastening screws 226 and 228. The heads may alternatively be smaller, and Discs can be inserted between the heads of the fastening screws and the portion of the anvil seat 216, against which the fastening screws 226 and 228 could otherwise directly rest. The substantially larger size of the fastening holes 230 and 232 with respect to the set screws 226 and 228, best seen in Figure 11, allows the anvil 32 to oscillate about the center 214 at least as much as one may wish to adjust the orientation of the anvil 32 relative to the bar 56 of the anvil. The clamping screws 226 and 228 are screwed into the corresponding threaded holes in the mounting surface 208. Alternatively, the screws 226 and 228 could pass through larger holes in the mounting surface "08 and be screwed into the holes correspondingly threaded, in the anvil seat 216. The fastening screws 226 and 228 have securing positions for securing the anvil seat 216 and the anvil bar 56, together, which are achieved by screwing the screws 226 and 228 sufficiently within the mounting surface 208, for securing the anvil seat 216 to the mounting surface 208. The fastening screws 226 and 228 have an adjustment position to allow the anvil seat to rotate about the center 214 relative to the bar 56 of the anvil, to align the anvil 32 with respect to the sealing horn 34 (Figure 1) .The adjustment position is reached by the loosening the screws 226 and 228 sufficiently, so that the anvil seat 216 can oscillate with respect to the mounting surface 208. Figure 10 illustrates that the anvils 32 and 42-54 are independently mounted to the mounting surface 208 , as previously described, so that they can oscillate independently around their respective centers of curvature, such as the center 214 for the anvil seat 216. Referring now to Figures 6-8 and 11, anvils such as 32 and transducers such as 34 of ultrasonic sealing apparatus 20 can be easily aligned before starting a production run. The fasteners or rivets such as 226 and 228 for all anvils 32 and 42-54 are first thrown to their adjustment positions. Then, if desired, the nominal contact positions of the anvils such as 32 and the sealing horns such as 34 can be established by closing them, together with light pressure, so that they come into contact in the nominal closing position, as illustrated in Figure 6. The contact between the sealing horns such as 34 and the anvils such as 32, causes the anvils such as 32 to travel around their centers such as 214., thereby orienting the anvils such as 32 in precisely parallel positions relative to the corresponding sealing horns such as 34. Rivets can be made then advanced to their securing positions to maintain the fit. Once the nominal orientation of the anvils has been established, the anvils and transducers can be set aside. Subsequently, or instead of carrying out the adjustment of the anvils such as 32 around their centers such as 214 with light closing pressure and without any cardboard box present, the gauges or widths representing the work pieces to be fastened ( which may simply be the upper fins 26 or the lower fins 28 of the cartons of the type that will be immediately run) may be inserted between each anvil such as 32 and the transducer such as 34, as shown in Figure 7. Fasteners or rivets such as 226 and 228 can be (or remain) thrown away. The gauges or widths 26 or 28 can be clamped between the anvils such as 32 and the transducers, or the sealing horns -almost like 34 using the full seal pressure that is intended to be exerted during the production run, as shown in Figure 8. The closing force will push any of the anvil seats such as 216, which are out of alignment to realign themselves by shifting around their centers such as 214. Fasteners or rivets such as 226 and 228 they can then be advanced to their respective underwriting positions to maintain the adjustment. An adjustment insert or wedge 237 may be placed between surfaces 212 and 236 to provide lateral adjustment.

Anvil Cooling Apparatus The anvils receive some of the ultrasonic energy from the transducers or the sealing horns, when the cardboard boxes are sealed. To prevent the anvils from overheating, the anvils can be cooled. For this purpose, cooling water can be directed through the anvils, to cool them down. With reference to Figures 10 and 11, each anvil such as 32 has an internal water passage 240 connecting its inlet and outlet nozzles, 222 and 224. Figure 10 illustrates that the water is taken from a water supply 242, which can be a municipal water supply. The water can be optionally sanitized, so that it can not contaminate the hygienic part of the machine in the event of a leak. The water from the supply 242 is brought to the anvil 54 via a flexible tube 244. The tube 244 is sufficiently long and extended in such a way that the alternating movement of the bar 56 of the anvil can be accommodated. The tube 244 is fitted over the nozzle 246 to pass the cooling water into the internal passages of the anvil 54. The cooling water leaves the outlet nozzle 248 of the anvil 54 via a bridge tube 250, which then directs the water towards the inlet nozzle 252 of the next anvil in the line, here the anvil 52. A similar series of bridge tubes 254-264 transmits the cooling water through each of the anvils in turn. Finally, an outlet tube 266 transfers cooling water from the last anvil in line (32) to a drain 268. Exit tube 266 is a flexible tube which is sufficiently long and deployed in such a way that it can be the alternating movement of the anvil bar 56 accommodated. Of course, the drain 268 can be omitted and the water can be cooled and recycled to the source 242 if that is desired, and particularly if the water has been treated with relatively expensive sanitizing agents, which are desirably recycled. Various adaptations of the present cooling system are illustrated in Figure 11. The elastic seat 220, typically made of rubber, ultrasonically and thermally insulates the front member 218 from the anvil of the anvil seat 216. Because the front member 218 is insulated, the cooling system may be limited to the front member 218. Also, to prevent the outer pipe and connections from being damaged or detached, they are all mounted on the anvil seats 32 behind of the elastic seat 220. The pipe and the connections themselves are therefore isolated from the ultrasonic energy. The internal water passage 240 itself has a portion 270 that passes through the elastic seat 220, directing water from an inlet nozzle 222 behind the seat 220 to a cooling area at the front of the seat 220. The internal passage of Water 240 has another portion 272, which passes through the elastic seat 220 and goes to the outlet nozzle 224 behind the seat 220. The elastic seat 220 acts as a gasket between the seat 216 and the front member 218.

Use of the Apparatus The apparatus described above can be used in a packing machine such as that described in the first U.S.S.N. 08 / 190,546, filed on February 2, 1994, which is incorporated by reference herein. The apparatus can be operated using a servo motor and the associated control system as illustrated in U.S.S.N. 08 / 315,414 (Attorney's Case No. 10623US01; Corporate Case No. TRX-0126), entitled "Control System for a Packing Machine", presented on the same date with this, which is likewise incorporated by reference. When the ultrasonic sealant is used to seal the bottom of a cardboard box with top part in pinion, in a packing machine as described in the patent application '546, this can be controlled using the control system illustrated in U.S.S.N. 08 / 315,414 (Case of Lawyer No. 10623US01; Corporate Case No. TRX-0126) which may implement the movement profile illustrated in Figures 15-17 of this application. Figures 15-17 illustrate exemplary acceleration, velocity, and position profiles for a simple seal cycle. The movement profile can include two movements. The first movement with motor, which occurs between approximately 0.2 seconds and 0.6 seconds in the cycle, rotates the cams to close the sealing jaws. The first motor movement begins with a sufficient lead time to ensure that the jaws make contact with the bottoms of the cardboard boxes just after the bottoms of the cardboard boxes remain in the plane of the jaws. The second movement with motor, which occurs between approximately 1.3 and approximately 1.6 seconds in the cycle, rotates the cams so that the sealing jaws open. For each movement, 15% of the movement time is spent accelerating, 70% of the movement time is spent at constant speed, and 15% of the movement of time is spent decelerating. The cams are shaped to move the jaws during the constant velocity portion of the movement, thus avoiding the possibility of adding the torque required to move the jaws to the torque required to accelerate the cams. Each movement of this profile is basically 15%, 70%, 15% trapezoidal speed profile. However, during the time of any acceleration (or deceleration) 20% of the acceleration time is spent in the gradual increase towards the constant acceleration, and 20% of the acceleration time is spent gradually decreasing to the zero acceleration. The gradual increase or decrease of the accelerations helps to prevent the rattle or vibration of the mechanism. When the ultrasonic sealing press is used as a top sealer, it can be moved according to the movement profiles illustrated in Figures 12-14. "1 movement can proceed according to two movements.

The first movement is an atypical movement consisting of three polynomial grooves. The first groove, which operates between about 0.6 and 0.7 seconds in the cycle, rotates the cams so that the jaws contact the upper sealing areas of the carton, generally simultaneously with the arrival of the crates. cardboard in the plane of. the jaws. The cams reach that point with a very low speed. The low speed of the cam was desired so that the speeds of the jaw could be sufficiently small to give refolding mechanisms, such as those illustrated in U.S.S.N. 08 / 315,400 (Case of Lawyer No. 10455US01, Corporate Case No. TRX-0047), entitled "Apparatus for Sealing the Fin of a Cardboard Box in Pinion", presented on the same date as this, the time to conform the parts top of the cardboard boxes for proper folding and sealing. At the same time, it is desirable to have some velocity greater than zero, so that the subsequent acceleration could be performed without having to overcome the static friction. The second groove of the movement, which operates between about 0.7 seconds and 0.8 seconds in the cycle, rotates the cams to the jaws - and thus, the tops of the cartons - are about 5 mm apart. It is desired that this movement lasts 100 milliseconds to continue giving time for the action of the refolding mechanisms, and allow excess air to escape from the cardboard box. It is also desired that the velocity at the end of the second groove be as low as possible while still making it possible for the jaws to finish closing in the next 100 milliseconds via the third groove. The low speed at the end of the second groove (and, thus, at the beginning of the third groove) is desirable to extend the time for exhaust air to proceed as far as possible towards the third groove. The third groove, which operates between approximately 0.8 seconds and 0.9 seconds in the cycle, has to decelerate as fast as possible to complete the rotation of the cam and the jaw closure in the 100 milliseconds assigned. The second movement, which acts between approximately 1.3 seconds and 1.6 seconds in the cycle, opens the upper sealing jaws and is the same as the movement that opens the lower sealing jaws. 15% of the movement time is spent accelerating, 70% of the movement time is spent at constant speed, and 15% of the movement time is spent decelerating. During the time of any acceleration (or deceleration) 20% of the time is spent increasing to constant acceleration and 20% of the time is spent decreasing to zero acceleration. Again, the rise and fall of the accelerations was implemented to reduce the rattle or vibration of the mechanism. The previous figures use units that are in degree, degree / second and degree / second 'of the rotation of the cam, instead of the radius or degrees of rotation of the motor, because the rotation of the motor is directly proportional to the rotation of the motor. the cam, and because the rotation of the cam is more significant for more people than the rotation of the motor.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the invention as above, property is claimed as contained in the following:

Claims (5)

1. An ultrasonic transducer assembly for hygienic ultrasonic sealing, characterized in that it comprises: A. a hygienic sealing area and an unhygienic area, separated by a first barrier having an opening defined by a marginal edge; B. an ultrasonic converter placed in the aperture, which is passed through the aperture along an axis passing through the aperture, and is vibrated at an ultrasonic frequency by the machinery placed in the area not hygienic, said converter having a null area in which the converter is vibrated substantially minimally; C. a sealing surface, generally cylindrical, fixed with respect to a first member, which is one of the marginal edge and the null area, said sealing surface facing a second member that is the other of the marginal edge and the null area; and D. a seal mounted on the second member and which rubs or cleans the sealing surface in general cylindrical, as the converter is moved alternately.

2. The transducer assembly according to claim 1, characterized in that the generally cylindrical sealing surface is defined by a sleeve or sleeve.

3. The transducer assembly according to claim 2, further characterized in that it comprises a second barrier defined by a beam extending between the sleeve and the first member.

4. The transducer assembly according to claim 1, characterized in that the first member is the null area and the second member is the marginal edge.

5. The transducer assembly according to claim 1, characterized in that the converter has a body and the null area includes a skirt that generally hangs along the axis from the body.