Abstract:
This invention relates generally to cutting product by ultrasonic tools and methods. Specifically, the invention relates to an elongated cutting element removably coupled to an ultrasonic resonant horn to form a cutting zone and a method of use. The elongated cutting element can include simple, less costly, easily replaceable elements that resonate at ultrasonic frequencies but don&#39;t follow complex and restrictive acoustic rules.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/760,566 filed on 19 Jan. 2006. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates generally to cutting product by ultrasonic tools and methods. Specifically, the invention relates to an elongated cutting element removably coupled to an ultrasonic resonant horn to form a cutting zone and a method of use. The elongated cutting element can include simple, less costly, easily replaceable elements that resonate at ultrasonic frequencies but don&#39;t follow complex and restrictive acoustic rules.  
         [0004]     2. Discussion of Related Art  
         [0005]     The advent of ultrasonic cutting technology in the last decade has thoroughly revolutionized the cutting operations of many industries including the food industry. However, even today, many new applications have to face the perceived high cost of ultrasonic components. Among such components, depending on the nature of the application, ultrasonic horns frequently top the list as the most expensive components even surpassing the cost of power supplies. For ultrasonic horn construction it is well known that, along with the use of expensive materials like titanium alloys, strict acoustic principles must be followed. For instance, the height of a blade horn must be exactly equal to half the wave length of the speed of sound in the particular material being used and commonly referred to as a half wave horn or a multiple of it, typically double and commonly referred to as a full wave horn. Moreover, the length of a horn is also significantly limited by other factors such as amplitude uniformity, frequency stability and reliability.  
         [0006]     As an additional aspect, the typical horn profile entails during its fabrication a significant waste of expensive alloy while the mechanical characteristics of the alloy require a very slow machining process. These facts compound the ultimate cost of the finished horn.  
         [0007]     The use of composite horns, i.e., a combination of multiple resonant elements connected to a common mother horn, although it is an option often used to contain the cost of the overall installation. However, composite horns are also costly, since their fabrication requires complex and expensive joining techniques such as: proprietary brazing processes, electron beam welding or time consuming fastening with threaded studs.  
         [0008]     While the high cost of ultrasonic horns contributes to the overall outlay of an ultrasonic cutting system, it has also a significant impact on its operating expenses. In fact, it is known in the art that ultrasonic horns are subject to extremely high stresses, due to their rapid contraction and expansion at the resonant frequency. Such condition is further enhanced for blade horns due to the sharp cross section transitions required by their extreme profile. Although, typically, the performance of blade horns is significantly compromised in favor of greater reliability by fabricating thicker blades and more blunt edge bevels, these blade horns are still frequently subject to frequency shifts and consequent cracking. In this event, even if, more often than not, the cracks are invisible to the naked eye, once the horn is cracked, it can no longer resonate at its natural frequency and it must be replaced.  
         [0009]     Another reason for periodic replacement of the blade horns resides with the progressive wear that is sustained by the blade edge during normal operation due to the repetitive engagement with the product, often abrasive like in the case of confectionery products. In addition to the cost issue of the conventional ultrasonic cutting horns, there are other important aspects to be addressed.  
         [0010]     First, conventional horn design typically involves a compromise between performance and reliability that more frequently favors the latter. Blades are frequently developed that are too thick and with blunt edge bevels of up to 15 degrees which make such designs unsuitable for many categories of food and non food products that don&#39;t have plastic or pliable characteristics. This is typical of crumbly or aerated products from baking processes, such as cookies, which under the wedge effect of a blunt thick blade break apart and crumble along unpredictable fault lines, resulting in unacceptable product appearance as well as intolerable scrap levels.  
         [0011]     Secondly, there are several other categories of products which are presently cut by cold and hot wire technologies or super thin blades, obviously because they are incompatible with either a standard blade design or a conventional ultrasonic blade horn. This is the case of products like wafers, ice cream, cheese, dough and the like. For such products, the existing prior art ultrasonic equivalent technology offers little improvement in cutting performance or allowing new product line extensions.  
         [0012]     For instance, any attempt to cut wafer stacks filled with anything different than the conventional creams such as, for example, caramel, jelly, marmalade, nuts, inclusions and the like, with the conventional wires or thin blades will have to contend with a variety of operational issues. The thin blades or wires will quickly build up with product and increase the cutting resistance which will cause deformation of the wafer stack; in turn the build up will eventually break loose and fall on the top of the finished products creating unacceptable quality issues.  
         [0013]     As an additional example, any attempt to cut a rope of ice cream extrusion such as for ice cream bars with sticks that contains inclusions of different kinds such as, for example, candied fruit, nuts, chocolate drops and the like, with the conventional hot wire technology may not result in desired product. In fact, while the hot wire can plow through a plastic mass with reasonable speed and final result, it would not be able to cut any inclusion. On the contrary, as soon as a hot wire would engage an inclusion, it would push it through the product creating pronounced deformations.  
         [0014]     Additionally, conventional ultrasonic blades during the cutting operations, inevitably, maintain contact with the cut surfaces of the product until the blade edge disengages the top the product during its up stroke. While this is tolerable by many products of plastic nature, there are a number of products that react negatively to the prolonged contact with abnormal melting, smearing and build-up on the blade. These effects are further pronounced depending on the thickness of the blade and the edge bevel angle. This is the case of co-extruded multicolor products as well as multilayer filled ones and other products which must be cut when hot. Such products would prefer being swept through by a thin and shallow blade which, by minimizing the time, area and force of contact with the cut surfaces of the product, will prevent all the above-mentioned side effects.  
         [0015]     Finally, although the ability to execute a profiled cutting with suitably shaped ultrasonic blades is now possible such as, for example, as disclosed in published U.S. Patent Application 20040134327 and the entire contents of which are hereby incorporated by reference, this option is still an expensive one.  
       SUMMARY OF THE INVENTION  
       [0016]     It is desirable to provide the use of a simpler, less expensive, easily replaceable blade. From the foregoing, there is a need for an innovative approach that could lead to simple, less costly, easily replaceable cutting elements that, on the one hand can still resonate at ultrasonic frequencies while on the other hand, don&#39;t need to follow the complex and restrictive acoustic rules. Such new cutting elements, by virtue of compact overall dimensions and in particular extreme thinness, can sweep easily through a variety of products with minimal intrusion and maximum efficacy. Also, some of these elements can be profiled through stamping methods. All things combined, such cutting elements will further simplify the cutting operations as well as lead to an array of new products or line extensions.  
         [0017]     It is also desirable to provide the following particular benefits. Desirable wafer manufacturing benefits include clean cuts with low forces, no product delamination and new fillings and/or inclusions. Desirable ice cream processing benefits include slices with no product distortion, faster cutting speeds, higher cutting rates, thin slices and inclusion cutting ability. Desirable cheese processing benefits include slices with a higher moisture content, inclusion cutting ability, dicing, portioning and slitting. Desirable converting Industry benefits include low cutting/scoring forces and higher rates. Foam application benefits include faster speeds and no burning and/or melting.  
         [0018]     The above and other objects of this invention can be attained, at least in part, with an apparatus for cutting product including an ultrasonic resonant horn desirably having a resonant frequency of about 20 khz to about 40 khz and at least one elongated cutting element removably coupled to the ultrasonic resonant horn. The at least one elongated cutting element preferably extends across a cutting zone between a first mounting site on the ultrasonic resonant horn and a second mounting site which may be on a second ultrasonic resonant horn or an anchor point. The elongated cutting element can have a ratio of a width to a thickness of less than about 25 and/or ratio of a length to a thickness of about 150 to about 600.  
         [0019]     Suitable elongated cutting elements may have a profiled shape and be drawn taught by a tensioning device. Elongated cutting elements may include rules or wires and are made of materials such as titanium, stainless steel and carbon steel. A rule may have a length of about 300 mm, a thickness of about 0.5 mm to about 2 mm and a width up to about 30 mm. A wire may include a round wire with a diameter of about 0.5 mm to about 3 mm, and/or a flat wire with a thickness of about 0.2 mm to about 2.5 mm and a width of about 2 mm to about 8 mm. According to a preferred embodiment of this invention, the elongated cutting element is attached at only a single mounting site.  
         [0020]     The elongated cutting element may removably couple to the ultrasonic resonant horn in orientations such as, for example axial, perpendicular and/or transverse. The apparatus may include an arm mounted to the ultrasonic resonant horn and the at least one elongated cutting element removably coupled to the arm forming a bow structure. Still, other preferred embodiments include a rotational drive mechanism engaged with the ultrasonic resonant horn. Four elongated cutting elements can removably couple to the ultrasonic resonant horn at about 90 degree angles to each other.  
         [0021]     Another object of this invention is to provide a method of cutting product including energizing an ultrasonic resonant horn having at least one elongated removably attached cutting element and contacting product with the at least one elongated removably coupled cutting element to form cut, sliced, slit, and/or portioned product which may include inclusions. This method may also include rotational movement from a rotational drive mechanism engaged with the ultrasonic resonant horn.  
         [0022]     Other objects and advantages will be apparent to those skilled in the art from the following detailed description taken in conjunction with the appended claims and the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]     The above and other objects of this invention can be better understood when the specification is read in view of the drawings, wherein:  
         [0024]      FIG. 1  is a sectional view of an apparatus for cutting product, according to one preferred embodiment of this invention;  
         [0025]      FIG. 2  is a partial exploded view of a perpendicular orientation according to one preferred embodiment of this invention;  
         [0026]      FIG. 3  is a sectional view of an apparatus for cutting product, according to one preferred embodiment of this invention;  
         [0027]      FIG. 4  is a partial exploded view of an axial orientation according to one preferred embodiment of this invention;  
         [0028]      FIG. 5  is a sectional view of an apparatus for cutting product with a rotational drive mechanism, according to one preferred embodiment of this invention;  
         [0029]      FIG. 6  is a sectional view of an apparatus for cutting product with a second ultrasonic resonant horn, according to one preferred embodiment of this invention;  
         [0030]      FIG. 7  is a sectional view of an apparatus for cutting product with a bow structure, according to one preferred embodiment of this invention;  
         [0031]      FIG. 8A-8C  are sectional views of rules, according to preferred embodiments of this invention;  
         [0032]      FIG. 8D-8E  are cross sectional views of rules according to preferred embodiments of this invention;  
         [0033]      FIG. 9A-9B  are cross sectional views of wires, according to preferred embodiments of this invention; and  
         [0034]      FIG. 10  is a sectional view of a rotary configuration, according to one preferred embodiment of this invention;  
         [0035]      FIG. 11  is a sectional view of an apparatus for cutting product with a composite horn, according to one preferred embodiment of this invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0036]      FIG. 1  shows a sectional view of apparatus  20  for cutting product  62  according to one preferred embodiment of this invention. Product  62  can include materials from various industries such as, for example, food, converting or any other industry with a need to cut, slice  64 , slit, score, portion or otherwise modify product  62 . Typically food items can include candies, breads, cakes, snacks, wafers  68 , cookies, dough, pasta, chewing gum, ice cream, marshmallow, cheese and/or any other suitable material. Product  62  can include fillings such as creams, jellies and the like. Product  62  can also include inclusions  66  such as candied fruit, nuts, chocolate and the like. Product  62  can be of any required dimension or size to facilitate manufacture or end use requirements. Miniature sizes of product  62  can be manufactured. Product  62  from other industries may include pet food, paper, wax, foam, plastic and/or other suitable materials.  
         [0037]     Apparatus  20  includes at least one ultrasonic resonant horn  22 . Suitable ultrasonic resonant horns  22  can include simplex or composite horns, i.e., a plurality of smaller horns forming a larger horn, of various sizes and frequencies. According to a preferred embodiment of this invention, ultrasonic resonant horn  22  has a frequency of about 20 khz to about 40 khz. Ultrasonic resonant horn  22  desirably will excite elongated cutting element  24  at a frequency of about 20 khz to about 40 khz. Those skilled in the art and guided by the teachings herein will appreciate the desire to utilize simple, low cost convention ultrasonic drivers and/or generators.  
         [0038]     At least one elongated cutting element  24  can be removably coupled, attached, mounted and/or fixed to ultrasonic resonant horn  22  at a first mounting site  28 . Removably coupled can allow for interchangeable elongated cutting elements  24 . Suitable solid connections transmit ultrasonic energy or are in ultrasonic communication between ultrasonic resonant horn  22  and elongated cutting element  24 . Mechanical couplings or can include threaded connections such as nuts, bolts, studs, threaded tips, coupling device and/or the like. According to a preferred embodiment of this invention, elongated cutting element  24  is removably mounted by a bolt and a washer which is torqued according to ranges based on size and material as know by those skilled in the art. Inadequate mounting may result in significant localized frictional heat build up from the rapid expansion and contraction of the ultrasonic driver resulting in reliability, performance and/or failure of the cutting system.  
         [0039]     According to a preferred embodiment of this invention, mounting also includes tensioning device  40  to hold elongated cutting element  24  in a taught, drawn and/or stretched position. Tensioning device  40  can be used with both rule  36  and wire  38  type of elongated cutting elements  22 . Tensioning device  40  desirably includes two components: a tensioning ring  78  with a suitable groove or slot  80  for the insertion of wire  38  end, and a threaded tip  74  and/or spacer  72  to clamp or hold tensioning ring to face of mounting site  28 . Slot  80  can be a slit part way into or through the tensioning ring in a manner similar to stinging a guitar. Wire  38  can be wound around the tensioning ring and then can be clamped on the desired spot of the ultrasonic resonant horn  22  by a threaded tip. Tensioning device  40  can be placed on any mounting site  28  or more than one mounting site  28  including anchor point  32  as shown in  FIG. 1  or arm  54  as shown in  FIG. 7 .  
         [0040]     Second mounting site  30  can removably mount elongated cutting element  24  to first ultrasonic resonant horn  22 , a second ultrasonic resonant horn  34  as shown in  FIG. 6  or anchor point  32  as shown in  FIG. 1 . Anchor point  32  can include any location or place that is not itself ultrasonically driven and may be rigid, dampened, and/or isolated.  
         [0041]     Elongated cutting element  22  can be rule  36 , wire  38  and/or other suitably thin design to sweep easily through a variety of products  62  with minimal intrusion and maximum efficacy. Cutting zone  26  is formed by elongated cutting element  22  between first mounting site  28  and second mounting site  30 . Apparatus  20  can have more than one cutting zone  26 .  
         [0042]     Rule  36  can be referred to as a band, a strip and/or a thin shallow blade.  FIG. 8A  shows rule  36  having a straight blade and  FIG. 8B  shows rule  36  having a serrated blade with varying teeth.  FIG. 8C  shows rule  36  having a profiled shape  42  as can be made by stamping methods and the like.  FIGS. 8D-8E  show possible cross sectional views of profiled shapes  42 . Other combinations of edges or profiles are possible beyond those shown herein for illustration purposes. Suitable materials of construction for rule  36  can include carbon steel, stainless steel, titanium and/or any other materials of suitable hardness and compatibility with product  62 . Preferably rule  36  has sufficient rigidity to properly function without tensioning device  40  and more preferably utilize a single mounting site  28 .  
         [0043]     Dimensions of rule  36  can desirably include: a length of about 300 mm; a thickness of about 0.5 mm to about 2 mm; and a height of up to about 30 mm. According to a preferred embodiment of this invention, elongated cutting element  24  has a ratio of width to thickness of less than about 25. According to another preferred embodiment of this invention, elongated cutting element  24  has a ratio of a length to a thickness of about 150 to about 600. Rule  36  can have one or more holes, apertures and/or bores located at the ends and/or anywhere in between the ends of rule  36  to facilitate attachment to a mounting site.  
         [0044]     Wire  38  can be referred to as a cord, a string, a cable and/or a line. Suitable materials of construction for wire  38  include those discussed above for rule  36 . Desirably, wire  38  includes inherent flexibility and merits the use of tensioning device  40 . Proper tension can prevent wire  38  from operating in flexural modes.  
         [0045]      FIG. 9A  shows a cross section of round/circular wire  50 .  FIG. 9B  shows a cross section of flat/rectangular wire  52 . Other wire  38  designs are possible beyond those shown herein for illustration purposes. Wire may be sharpened before installation and/or typically a suitable edge can be applied or sharpened once installed in apparatus  20 . According to a preferred embodiment of this invention, dimensions for wire  38  are as follows: round having a diameter of about 0.5 mm to about 3 mm, more preferably about 2 mm; flat having a thickness of about 0.2 mm to about 2.5 mm, more preferably about 0.25 mm and having a width about 2 mm to about 8 mm, more preferably about 2 mm to about 4 mm.  
         [0046]     Elongated cutting element  24  can be connected to ultrasonic resonant horn  22  in a variety of geometric configurations to optimize cutting performance and/or type of cut. Perpendicular  48 , axial  44 , and transverse  46  orientations are described below but other orientations are possible beyond those shown herein for illustration purposes.  
         [0047]     Perpendicular orientation  48 , as shown in  FIGS. 1-2 , can be formed by placing the width of elongated cutting element  24  at a substantially right angle to the end of the ultrasonic resonant horn  22 . Typically, but not necessarily, perpendicular orientation  48  includes mounting by a threaded connection aligned in an axial direction with the expansion and contraction of the ultrasonic resonant horn  22 .  FIG. 2  shows a partial exploded view of a perpendicular orientation  48  including washer or spacer  72  and bolt or threaded tip  74 .  
         [0048]     Axial orientation  44 , as shown in  FIGS. 3-4 , can be formed by placing the width of elongated cutting element  24  substantially parallel to the end of the ultrasonic resonant horn  22 . Typically, but not necessarily, axial orientation  48  includes mounting by a threaded connection aligned in a perpendicular direction to the expansion and contraction of the ultrasonic resonant horn  22 .  FIG. 3  shows a partial exploded view of an axial orientation  44  including washer or spacer  72  and bolt or threaded tip  74 .  
         [0049]     Transverse orientation  46 , as shown in  FIG. 6 , can be formed by taking the axial orientation  44  and rotating elongated cutting element  24  to be substantially perpendicular to the end of the ultrasonic resonant horn  22 . For example, cutting element  24  being vertical, i.e., blade side up and/or down, and having a perpendicular orientation  48  is distinguished from a transverse orientation  46  wherein cutting element  24  being horizontal, i.e., blade side left and/or right.  
         [0050]     According to a preferred embodiment of this invention, as shown in  FIG. 7 , arm  56  can be attached and/or mounted to the ultrasonic resonant horn  22  and also removably attached to elongated cutting element  24 . Cutting element  24  can form cutting zone  26  between ultrasonic resonant horn  22  and arm  56 . Bow structure  56  may result from this configuration. Bow structure  56  may typically include nodal ring  70  attached, disposed and/or interposed between ultrasonic resonant horn  22  and arm  56 .  
         [0051]     Rotational drive mechanism  58  may be provided to impart additional functionality to apparatus  20  as shown in  FIG. 5 . Rotary ultrasonic cutting may allow shapes and processes that are not possible with conventional reciprocating methods, such as for example creating miniatures. One or more elongated cutting elements  24  can be used in a rotary configuration wherein generally cutting elements can be arranged in a substantially symmetrical configuration or fashion. According to a preferred embodiment of this invention, as shown in  FIG. 10 , four cutting elements are arranged at substantially 90 degrees to each other to form rotary tip  60 . Rotary tip  60  can be connected to one or more ultrasonic resonant horns  22  and one or more rotational drive mechanisms  58 .  
         [0052]     According to a preferred embodiment of this invention and shown in  FIG. 11 , a composite horn  76  supplies the ultrasonic motive force to apparatus  20 . According to a preferred embodiment of this invention and as shown in  FIG. 11 , composite horn  76  includes a back driver or mother horn  84  and two front cylindrical resonant drivers  82  or arms with tips or ends. Other combinations of composite horn  76  elements are possible beyond those shown herein for illustration purposes.  
         [0053]     Ultrasonic devices can be generally of any size needed from large fixed units to smaller portable ones. Preferably the unit is substantially rigidly attached and/or mounted to a suitable superstructure.  
         [0054]     Methods for use of apparatus  20  for cutting product  62  include energizing or turning on an ultrasonic resonant horn  22  having at least one elongated removably attached cutting element  24 . Contacting, exposing, and/or touching product  62  in cutting zone  26  with elongated cutting element  24  to form, slice, portion and/or shave product  62 .  
         [0055]     Additional configurations and/or steps are possible such as, for example, supplying product on a conveyor belt across the apparatus  20  or other suitable automation methods and/or equipment. In addition to rotational drive mechanism  58 , other motive devices for elongated cutting element  24  are possible such as, for example, reciprocating movement, linear movement, circular movement, curved movement and the like. One skilled in the art and guided by the teachings herein will appreciate that ultrasonic cutting can be selectively applied such as, for example, when cutting a product having a hard top surface with an interior that maybe damaged by ultrasonic energy.  
         [0056]     Combinations of apparatus  20  may be utilized to offer additional processing flexibility such as, for example, using multiple elongated cutting elements  24  arranged in a grid so that a block of product can be diced at one time. According to a preferred embodiment of this invention, an array or arrangement of of a plurality of resonant drivers  82  extend from one or more simplex ultrasonic resonant horns  22  and/or composite horns  76 . Elongated cutting element  24  can be removably coupled to each resonant driver  82  and to an anchor point  32  so that product  62  can be sliced and/or diced when contacting elongated cutting element  24 . Elongated cutting elements  24  can be arranged and/or configured in a substantially parallel manner or any other suitable combination.  
         [0057]     While in the foregoing specification this invention has been described in relation to certain embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention.