Apparatus for cooling ultrasonic tube sealers

A conventional ultrasonic tube sealing device is modified for dissipating undesirable heat energy by locating in close proximity to a horn a heat sink block, causing via pneumatic means the heat exchange block to make contact with the horn only when the horn is in an open retracted position with respect to an anvil, and causing the heat exchange block to separate from the horn when the horn is in a closed sealing position with respect to the anvil. The heat exchange block cools the heat exchange block by drawing off undesirable heat energy, yet, by separating during the sealing mode, allows the horn to function properly and does not adversely affect its ultrasonic properties. The heat exchange block may be cooled by transporting through strategically located passageways an externally cooled fluid.

FIELD OF THE INVENTION 
The present invention relates to a method and apparatus to provide a heat 
sink in order to cool devices which use ultrasonic energy for sealing 
tubes containing cosmetics and the like. 
BACKGROUND OF THE INVENTION 
It has long been customary to merchandise many products in tubes. Typical 
products packaged in tubes include toothpaste, lotion, caulking compound, 
etc. Currently, tube filling is generally performed by automated 
machinery. Rotary piston tube filling machines are probably the most 
common machinery now in use for filling tubes. Typical examples of rotary 
piston tube filling machines are shown in U.S. Pat. No. 2,958,346 and U.S. 
Pat. No. 3,825,043. Additionally, such machines are currently manufactured 
by Norden Packaging Machinery AB, Kalix Inc., Iwk Packaging Machinery, 
Inc. Pack. Dev. Co. Ltd. and Aktron, Inc. 
A tube filling and sealing station made by the assignee of the present 
application, Innovation Automation Inc., is described in U.S. Pat. No. 
5,209,044 to D'Addario et al., which is incorporated herein by reference. 
The apparatus of D'Addario et al. rapidly and efficiently fills tubes of 
various sizes and dimensions and avoids or minimizes the delays from 
inadvertent spills and misalignments that typically occur in a rapid tube 
filling operation. The apparatus is comprised of a rotating disc having a 
plurality of stations in which filling functions associated with the 
filling of tubes on a production basis occur. The disc is provided with a 
plurality holes in which tube filling support means are inserted to retain 
the tubes and enable simultaneous operations at a plurality of stations. 
The disc is provided with plastic collars at each hole to accommodate the 
tube support means for both rotation and secure placement. Work stations 
are provided in registry with the rotating disc and comprise a means for 
loading tubes into the tube holders, means for properly registering and 
determining registration and orientation of the tube for subsequent 
functions, reject means, cleaning means, filling means, sealing means, 
trimming means, and tube eject means. 
FIG. 1 shows a prior art sealing device 2 marketed by AMTECH which may be 
used in the tube filling apparatus of the prior art. A filled but unsealed 
tube 4 is encased by a cylindrical tube support member 8 and moved into 
position for sealing via an indexing motor 6. An anvil 10 is positioned on 
one side of the unsealed tube 4 and a horn 12 is positioned on an opposite 
side of the unsealed tube 4 in an open position. The anvil 10 and horn 12 
laterally move from the open position towards the tube 4 into a sealing 
position so as to pinch the tube end to be sealed against each other. The 
anvil 10 then remains stationary, and the horn 12 vibrates to emit a burst 
of ultrasonic energy to effect a seal of the tube end. The ultrasonic 
sound waves cause the molecules in the tube material to vibrate, drift 
together and solidify into the desired seal. The anvil 10 and horn 12 then 
retract away from the tube 4 to the open position after sealing. When the 
sealing process is complete, a sealing device computer 77 sends a signal 
to a main computer (not shown) to continue processing and to load the next 
open tube for sealing. 
The molecular action of the ultrasonic sealing process generates heat 
energy which is dissipated from the inside of the seal out towards the 
anvil 10 and horn 12. When large tubes are ultrasonically sealed in 
accordance with this prior art method and apparatus, longer dwell times 
are required to effect a proper seal. As a result, it has been discovered 
that more heat is generated and undesirably transmitted back to the anvil 
10 and horn 12. The excess heat changes the physical properties of the 
anvil 10 and horn 12 and causes the sealer to use excessive energy, which 
leads to an overload condition. Thus, it has been desired to cool the 
ultrasonic sealer already in use in the prior art tube filling stations in 
order to negate the effect of excessive heat generated from sealing large 
tubes. 
In the prior art, the anvil 10 is cooled via a heat exchange medium such as 
externally cooled water which is transported through a number of 
passageways disposed through its body. This type of cooling may only be 
implemented on the anvil 10 since it remains fixed during the sealing 
process and does not vibrate to emit ultrasonic energy to effect the seal. 
The horn 12, however, cannot be cooled in this manner since the use of 
such a cooling means undesirably affects its ultrasonic vibration 
properties. 
The simplest way to cool the horn 12 of the sealing device 2 is to 
intermittently stop or slow down the machine and allow it to cool. This is 
undesirable since it decreases the productivity from the filling 
apparatus. Another way to cool the horn 12 is to blow cool air over its 
surface and convectively cool it. This, however, only imparts minimal heat 
transfer and has not resulted in desirable cooling effectiveness. 
It is thus an object of the present invention to provide an apparatus and 
method to effectively cool an ultrasonic sealing device which is already 
in use in an existing tube filling and sealing production line. 
It is a further object of the present invention to provide an apparatus and 
method to effectively cool such an ultrasonic sealing device without 
slowing down or stopping the tube filling and sealing production line. 
It is a further object of the present invention to provide an apparatus and 
method to effectively cool such an ultrasonic sealing device without 
adversely affecting the ultrasonic sealing properties of the device. 
It is a further object of the present invention to provide an apparatus and 
method to effectively cool such an ultrasonic sealing device which 
overcomes the deficiencies of the prior art. 
SUMMARY OF THE INVENTION 
In accordance with this and other objects, the present invention is a 
method and apparatus for cooling an ultrasonic sealing device which 
overcomes the disadvantages of the prior art. When implemented in 
conjunction with the ultrasonic sealing device of the prior art as 
described above, the cooling apparatus comprises a heat exchange block 
located in close proximity to the horn of the ultrasonic sealing device 
when the horn is in the closed, or sealing, position. A pneumatically 
controlled piston is operatively associated with the heat exchange block 
to cause it to contact the horn only when the horn retracts to an open 
position and to remove the heat exchange block from contact with the horn 
when the horn advances to the sealing position. 
As a result of the apparatus of the present invention, the heat exchange 
block is in contact with and draws heat from the horn only when the horn 
is in the open position but not when the horn is in the sealing position. 
Thus, the ultrasonic sealing properties of the horn are unaffected by the 
heat exchange process since there is no contact with the heat exchange 
block during the ultrasonic sealing operation. By contacting the heat 
exchange block with the horn during the open non-sealing phase of the 
process, the horn is cooled on at least an intermittent basis. 
In order to continually and effectively draw heat from and thus cool the 
heat exchange block, the heat exchange block may have passageways disposed 
strategically throughout for effecting transport therethrough of an 
externally cooled fluid such as water. The cooling apparatus then also 
comprises means for providing to and from the heat exchange block 
passageways the externally cooled fluid, typically comprising water supply 
and drain leads. Thus, the heat exchange block will continually provide a 
cool surface relative to the ultrasonic sealing device and sink heat away 
accordingly.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The preferred embodiment of the present invention will now be described 
with reference to the prior art ultrasonic tube sealing device shown in 
FIG. 1 and described above. Referring to the figures, a heat exchange 
block 20, which in the preferred embodiment is aluminum, is located so as 
to be in substantial contact with an underside 13 of the horn 12 when the 
anvil 10 and horn 12 are in the open, or retracted, position. 
The aluminum block 20 is operatively associated with a pneumatic piston 22. 
A first air hose 24 and a second air hose 26 are coupled from a pneumatic 
controller 28 to the piston 22. The first air hose 24 controls the piston 
22 so as to effect downwards movement of the aluminum block 20, and the 
second air hose 26 controls the piston 22 so as to effect upwards movement 
of the aluminum block 20. The pneumatic air hoses 24, 26 are operatively 
associated with the pneumatic controller 28 which drives the advancing and 
retracting (closing and opening) of the anvil 10 and horn 12 towards and 
away from each other such that the operation of the piston 22 is in 
synchronization with the lateral movement of the anvil 10 and horn 12. 
When the anvil 10 and horn 12 are in the open or retracted position, the 
piston 22 causes the aluminum block to press against the underside 13 of 
the horn 12, thus acting as a heat sink and cooling the horn 12. When the 
pneumatic controller 28, under command of the sealing device computer 77, 
advances the anvil 10 and horn 12 towards each other so as to pinch 
therebetween the open end of the tube 4, the piston 22 is caused via the 
air hose 24 to effect downward movement of the aluminum block 20 away from 
the horn 12. 
After the ultrasonic sealing operation is completed, the pneumatic 
controller 28 causes the anvil 10 and horn 12 to retract away from each 
other back to the open position. The controller 28 synchronously causes 
via the air hose 26 the aluminum block 20 to move upwardly towards the 
underside 13 of the horn 12 so as to make contact therewith. Any heat 
generated by the ultrasonic sealing process is drawn from the horn 12 as a 
result of contact with the aluminum block 20. 
This up/down movement of the aluminum block 20 continues in synchronization 
with the open/close movement of the anvil 10 and horn 12 so as to provide 
efficient cooling of the horn 12 without affecting its ultrasonic 
properties during the sealing process itself. 
The aluminum block 20 comprises passageways 30 disposed throughout in order 
to effect transport of an externally cooled fluid and thus draw heat from 
the block 20 on a continual basis, thus maintaining the heat sink 
effectiveness of the block 20 in relation to the horn 12. The externally 
cooled fluid can be supplied by any known means available in the prior 
art. 
The horn 12 does not vibrate at all when it is in the non-sealing retracted 
position. This is significant since the horn 12 could be damaged if it 
were to vibrate while in contact with the cooling block 20. 
Although the preferred embodiment has been described in relation to an 
ultrasonic tube sealing device which implements an anvil and a horn, it is 
understood that the present invention can be implemented with any type of 
ultrasonic sealer and modified in accordance with the user's needs. For 
example, if an ultrasonic sealer is used which comprises two horns, each 
horn can be equipped with similar cooling mechanisms synchronized to their 
particular sealing operations.