Abstract:
An ergonomic horn for use in an ultrasonic welder having a base structure defining a first longitudinal axis, where the base structuring is connectable to the ultrasonic welder, and a tip mounting head defining a second longitudinal axis. The second longitudinal axis is angled relative to the first longitudinal axis to permit an ergonomic positioning of the item to be welded. The tip mounting head is operable to support a removable ultrasonic welding tip member. The ergonomic horn further having a reduced thickness neck portion interconnecting the base structure and the tip mounting head, such that the base structure, tip mounting head, and reduced thickness neck portion together transmit ultrasonic energy in the range of approximately 10 kHz to approximately 60 kHz for ultrasonic welding.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/175,609, filed on May 5, 2009. The entire disclosure of the above application is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to ultrasonic welding horns and, more particularly, relates to an ergonomic ultrasonic welding horn. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     Ultrasonic energy has been shown to be a useful tool in a wide variety of applications from very low power medical diagnostics through high intensity processes which change the state of materials. Joining of metals, specifically nonferrous metals used in electrical connections, is a particularly useful application of this technology. Commonly used techniques involving the fusion of metal through the application of heat by flame, hot tools, electric current or electric arc in combination with cleaning and fluxing agents and sometimes filler metals are able to join these materials but the characteristics of these processes and the materials to be joined are at odds with one another. Still, users have become accustomed to the problems associated with fusion welding to the point that the problems are considered “normal.” 
     Ultrasonic welding of nonferrous metals in electrical connections has been demonstrated to eliminate most, if not all, of these problems. In fact, ultrasonic welding of metals is rapidly becoming the process of choice by informed design and manufacturing engineers. The number of applications and reduced operating expenses have led to wide use of ultrasonic welding for wiring and interconnection applications. 
     Since the first ultrasonic welding machine for metals was developed and patented in 1960, there have been significant technological advances which now make the process a practical production tool. Early power supplies, employing vacuum tube technology, could not produce high power levels of ultrasonic energy and were inefficient and expensive. Early work was limited to research and development which showed the promise of the process and spurred further technical development. Today, ultrasonic energy in general is a well established tool of industry having applications in nondestructive testing, industrial ultrasonic cleaning, ultrasonic plastic joining and ultrasonic metal welding. Ultrasonic metal welding has much to offer the user including speed, efficiency, excellent weld quality, elimination of consumables, long tool life and the ability to be automated. 
     Generally, ultrasonic energy is mechanical vibratory energy which operates at frequencies beyond audible sound, or 18,000 Hz (18,000 Hz being the upper threshold of the normal human hearing range). Two basic frequencies are generally used; 20,000 Hz and 40,000 Hz, depending on the application. Selection is based upon the required power levels, the amplitude of vibration required and the size of the ultrasonic tool to be used. Frequency is important because it directly affects the power available and the tool size. It is easier to generate and control high power levels at the lower frequency. Also, ultrasonic tools are resonant members whose size is inversely proportional to their operating frequency. The generation of ultrasonic energy starts with conversion of conventional 50 or 60 Hz electrical power to 20,000 or 40,000 Hz electrical energy by a solid state power supply. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     According to the principles of the present teachings, an ergonomic horn for use in an ultrasonic welder having an advantageous construction is provided. The ergonomic horn comprises a base structure defining a first longitudinal axis, where the base structuring is connectable to the ultrasonic welder, and a tip mounting head defining a second longitudinal axis. The second longitudinal axis is angled relative to the first longitudinal axis to permit an ergonomic positioning of the item to be welded. The tip mounting head is operable to support a removable ultrasonic welding tip member. The ergonomic horn further having a reduced thickness neck portion interconnecting the base structure and the tip mounting head, such that the base structure, tip mounting head, and reduced thickness neck portion together transmit ultrasonic energy in the range of approximately 10 kHz to approximately 60 kHz for ultrasonic welding. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  is a perspective view of an ultrasonic welder having an ergonomic horn according to the principles of the present teachings; 
         FIG. 2  is a perspective view of the ergonomic horn of the present teachings; 
         FIG. 3  is a side view of the ergonomic horn; 
         FIG. 4  is a top view of the ergonomic horn; 
         FIG. 5  is a tip-end view of the ergonomic horn; 
         FIG. 6  is an enlarged side view of the tip of the ergonomic horn; 
         FIG. 7  is an enlarged tip-end view of the ergonomic horn; 
         FIG. 8  is an enlarged view of an alignment slot formed in the ergonomic horn; and 
         FIG. 9  is a partial cross-sectional view of the ergonomic horn. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully with reference to the accompanying drawings. 
     The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     When an element or layer is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to”, “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments. 
     Referring to the figures and in  FIG. 1  in particular there is shown an ultrasonic half-wavelength resonator system  100  and a means for energizing the resonator system, such as an electrical generator. A half wavelength resonator is characterized by an antinodal region of longitudinal motion at both the input surface and the output surface and an intermediate nodal region of longitudinal motion. The electrical generator converts line voltage to a predetermined high frequency electrical signal. The predetermined frequency is usually in the range between one and 100 kilohertz, preferably in the range between 20 and 60 kilohertz. The electrical signal from the electrical generator is provided to an electro-acoustic converter  110  (in some embodiments, the electro-acoustic converter can be integral with the generator which converts the electrical energy applied at its input into mechanical vibratory motion of the predetermined frequency manifest at the output surface of the converter. Electro-acoustic converter  110  can be of conventional design, if desired. The converter can further be constructed in accordance with the teachings of U.S. Pat. No. 4,315,181, issued to Holze, Jr., dated Feb. 9, 1982, entitled “Ultrasonic Resonator (Horn) with Skewed Slots.” While electro-acoustic converter  110  is preferably an electro-acoustic converter, a magnetostrictive converter could be used. 
     Still referring to  FIG. 1 , electro-acoustic converter  110  can then be operably coupled to a diaphragm  114 , which transmits the mechanical vibratory motion from electro-acoustic converter  110  to a horn  10  via a threaded stud (not shown) for ultrasonic welding according to the principles of the present teachings. Referring to  FIGS. 2-9 , horn  10  is illustrated as an ergonomic horn. The ergonomic design of the horn of the present teachings offers manufacturers the fastest and cleanest method of reliably assembling components. Moreover, as will be described, the ergonomic horn  10  of the present teachings defines a shape that is conducive to safe and comfortable ultrasonic welding by an operator without the need for unhealthy contortion of the hands, wrists, or body. In some embodiments, ergonomic horn  10  is made of titanium, although other materials are anticipated. 
     To this end, as seen in  FIGS. 3-5 , ergonomic horn  10  comprises a generally cylindrical base structure  12  terminating at a mounting face  14 . In some embodiments, base structure  12  can define a diameter of about 1.720 inches. However, it should be appreciated that such dimension, including other dimensions sets forth herein, can change depending upon design variations and/or intended performance. 
     Mounting face  14  comprises a mounting aperture  16  ( FIG. 9 ) threadedly formed to threadingly engage the threaded stud of converter  110  to permit transmission of mechanical vibratory energy to ergonomic horn  10 . Ergonomic horn  10  can further define a neck portion  18  extending from base structure  12  generally along a longitudinal axis of ergonomic horn  10 . Neck portion  18  can be arcuately shaped and, in some embodiments, can define a radius of about 3 inches. 
     Ergonomic horn  10  can further comprise a scalloped portion  20  extending along a portion of base structure  12  and neck portion  18 . Scallop portion  20  can be used to remove material from ergonomic horn  10  to tune a predetermine response to the mechanical vibration, reduce horn mass, tailor overall device packaging, and the like. In some embodiments, scallop portion  20  can define a plane have a 12 degree slope relative to a longitudinal axis of base structure  12 . A joining radius  22  can be formed between scallop portion  20  and neck portion  18 . In some embodiments, joining radius  22  can be about 1.250 inches. Ergonomic horn  10  can further comprise a tip mounting head  24  extending from neck portion  18  and, in some embodiments, integrally formed therewith. Tip mounting head  24  is inclined at an angle to permit the ergonomic positioning of a tip member  26  ( FIG. 1 ) thereon. Tip mounting head  24  extends from neck portion  18  and defines a platform  28  for positioning and supporting tip member  26 . 
     The platform  28  includes a first section  30  and a second section  32 . First section  30  is generally adjacent neck portion  18  and generally comprises a cylindrical shape. In some embodiments, first section  30  can comprise a plurality of optional orientation surfaces  34  cut therein. The plurality of optional orientation surfaces  34  can have any keyed shape or layout, such as but not limited to four generally flat surfaces cut into first section  30  (see  FIG. 7 ). It should be appreciated that the plurality of orientation surfaces  34  can be eliminated and are thus optional. 
     Second section  32  can comprises a cylindrical shape having a diameter less than a diameter of the cylindrical section of first section  30 . The shape of tip mounting head  24  can be sized to closely conform to an interior profile of tip member  26  to create a simple and reliable coupling interface. In some embodiments, tip mounting head  24  is angled between about 8 and about 23 degrees relative to a longitudinal axis of base structure  12  to provide the proper orientation and ergonomic positioning of tip member  26  during operation. This angle also serves to provide a reliable orientation capable of transmitting ultrasonic energy efficiently and reliably without damage or interference. 
     Moreover, in some embodiments, tip member  26  can be made of steel and be removably coupled with tip mounting head  24  of ergonomic horn  10  through any conventional fastening system, such as a threaded stud, friction fit, interference fit, and the like. To achieve the proper coupling of tip member  26  to tip mounting head  24  to permit proper ultrasonic welding, tip member  26  is torqued to about 70-90 ft/lbs. This setting has been found to achieve the desired joining connection of tip member  26  to tip mounting head  24 . 
     As best seen in  FIGS. 2 ,  3 , and  8 , to achieve the proper orientation of ergonomic horn  10  relative to an operator, it may be desirable to ensure that ergonomic horn  10  is rotated to a predetermined position. To this end, a key slot  36  is longitudinally formed in base structure  12  of ergonomic horn  10 . Key slot  36  can be positioned at any position relative to a set screw or other fixed orientation member (not shown) in resonator system  100 . The set screw can be sized to be positively received within key slot  36  to achieve the predetermined position. In some embodiments, as seen in  FIG. 8 , key slot  36  is an angled cutout. 
     Conventional horns are generally symmetrical about a longitudinal axis and, thus, the forces exerted on the horn are generally easily modeled. However, because of the particular shape of ergonomic horn  10 , forces exerted during the ultrasonic welding process can be concentrated in some areas while excess mass in other may not afford much benefit. Therefore, the shape of the present ergonomic horn has been determined through finite analysis to provide the desired structural integrity while simultaneously minimizing mass. 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.