Patent Abstract:
This disclosure concerns methods, systems and apparatus that can be automatically activated by means of insertion into a jack socket and designed such that when inserted, no longitudinal force is exerted on the jack. In particular, self-muting connectors employ a spring-biased switch with an internal spring and a protrusion. When the connector is disconnected, the protrusion extends outwardly of a ground sleeve and the spring contacts an inner signal conductor. In this state, the switch shorts the signal conductor and ground sleeve together. When the connector is inserted into a complementary jack socket, the protrusion is urged inwardly and the spring deformed such that it ceases to contact the inner conductor, thereby the breaking the short-circuit between the signal conductor and ground sleeve. This allows a normal electrical connection to be established between the connector and the device to which the connector is inserted.

Full Description:
CROSS REFERENCE TO RELATED CASES 
     This is a continuation-in-part application of co-pending PCT International Application PCT/US2006/01782 with an international filing date of Jan. 17, 2006 and entitled “Self-Muting Audio Connector” which application is hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to audio signal phone connectors, and in particular to such a connector providing a means for establishing an automatic grounded termination for the connector upon removal of the connector from an external jack. Accordingly, the general objects of the invention are to provide novel systems, methods, and apparatus of such character. 
     2. Description of the Related Art 
     The present invention is an improvement in an electrical connecting device commonly known as a “phone plug” which terminates an electrical cable and permits the cable to be readily connected and disconnected to electrical apparatus. In addition to its many other applications, the phone plug has become the standard device by which electrically amplified musical instruments are connected to their amplifiers. One of the characteristics of the phone plug that has elevated it to a standard piece of equipment for an electrical cable, is the elegant simplicity of its design. The phone plug, which has no moving parts, is sturdy and sure in performing its function permitting it to be connected and disconnected countless times without failure. The mechanical and electrical features of conventional phone connectors and jacks are well known in the art and have become standard, universally used components in the field of audio electronics. 
     What is also universal, however, is the highly undesirable noise that occurs when a phone plug is connected or disconnected from an instrument while the instrument&#39;s amplifier is on. Under those circumstances, it is virtually impossible to either insert or withdraw the phone plug from its jack without the tip from contacting some signal generating element, whether it be part of the jack, the person handling the equipment, or some other nearby object. When the tip makes such contact, the result is an annoying and potentially dangerous sound emanating from the speakers being driven by the amplifier to which the cable is connected. This is an annoying and unwanted noise and can be quite loud, especially for a performing musician in front of an audience. 
     To avoid this problem in the past, musicians had to either unplug the end of the cable that is inserted into the amplifier, or turn the amplifier volume down so that the cable could be inserted into the instrument quietly. In both cases, the musician had to take an extra step to avoid the unwanted noise. In some cases, the amplifier can be a considerable distance from the front of the stage so it can be inconvenient to do this. A professional musician might need to change instruments several times during a performance thereby compounding the problem. 
     These deficiencies have led to the development of audio connectors having ground switches integrated into the connector itself. These products attempt to solve this problem, however, they have been unsatisfactory as either too complicated, too costly, too unreliable, or some combination thereof. One such self-muting connector has been commercialized by Deltron. The Deltron device employs a pair of coaxial ground sleeves arranged such that one externally spring-biased sleeve may slide longitudinally relative to the other to thereby permit selective grounding based on insertion and/or removal of the connector. In practice however, the Deltron design exerts a longitudinal spring force such that it may at least partially eject the phone connector from the socket. In particular, some jack sockets have weak tip springs and are therefore not capable of holding the plug in place. If so, the plug can be ejected sufficiently to so that the signal is lost intermittently or entirely. For a performing musician, this presents a significant reliability issue. It is not desirable to be part way through a song or a solo when the signal disappears. 
     A second commercially available design is available from a company called Planet Waves who offers a phone connector with a manually operated switch on the side of the phone connector body. This allows the musician to manually switch the signal off before unplugging the jack from the socket. The problem with this solution however is that it still presents the musician with an extra action that needs to be performed, usually under pressure. Additionally, it is difficult to see if the switch is on or off, so the musician might not get any sound from his amplifier and/or may not deduce that it is caused by the switch being engaged in the off position. 
     A third connector design that solves some of the above noted problems is taught by U.S. Pat. No. 5,466,167 to Scherer. The self-muting device of the &#39;167 patent offers the benefits that it (1) offers automatic switching operation; and (2) does not apply a longitudinal force that may tend to eject the connector from a complementary jack socket. The device taught by the &#39;167 patent, however, is still less than optimal for a number of reasons. First, the design still involves a modest level of expense and complexity to manufacture. This aspect is critical because of the high-volume and marginally profitable nature of such devices. Second, the device of the &#39;167 patent introduces reliability concerns that tends to undermine one of the most valuable characteristics of conventional phone connectors: astounding reliability over an extended period of time and repeated usage. 
     For these reasons alone, these prior art devices, as well as others of the same general description, have still not enjoyed any significant commercial success after many years. 
     There is, accordingly, a need in the art for improved methods, systems and apparatus to eliminate the effects of spurious extraneous signals, undesired signal emissions and signal reflections on the circuitry connected to the phone connector. In particular, such methods and apparatus should provide a simple and inexpensive connector which can be automatically muted whenever it is disconnected from an external jack socket. Such methods, systems and apparatus will ideally offer users/purchasers an optimal combination of (1) simplicity; (2) reliability; (3) economy; and (4) versatility. 
     SUMMARY OF THE INVENTION 
     The present invention satisfies the above-stated needs and overcomes the above-stated and other deficiencies of the related art by providing methods, systems and apparatus that can be automatically activated by means of insertion into a jack socket and designed such that when inserted, no longitudinal spring force is exerted on the jack socket. In particular, self-muting connectors in accordance with the invention employ a spring-biased switch with an internal spring and a partially exposed protrusion. When the connector is in a disconnected state, the protrusion extends outwardly of a ground sleeve and the spring contacts an inner signal conductor. In this state, the switch shorts the signal conductor and ground sleeve together. When the connector is inserted into a complementary jack socket, the protrusion is urged inwardly and the internal spring is deformed such that it ceases to contact the inner conductor, thereby the breaking the short-circuit between the signal conductor and ground sleeve. The breaking of this connection allows a normal electrical connection to be established between the connector and the device to which the connector is inserted. The invention may be applied to both monophonic and stereo phonic audio phone connectors. 
     The spring switch may comprise a conductive conductor-engaging member, a ground-sleeve engaging member and a resilient (or spring biased) intermediate member. The ground-sleeve engaging member is in substantially continuous contact with the inner surface of outer sleeve and the conductor-engaging member is in selective contact with inner signal conductor. Alternatively, the spring switch may be a coil spring that is substantially “e-shaped” in cross-section. 
     Other important aspects of the invention include a novel internal spring switch for use in an inventive self-muting connector of the type discussed herein. One advantage of this switch is that it is not physically affixed to any other part therefore needs no assembly procedures or complicated attachments other than a simple insertion. 
     The invention can also take the form of a method of manufacturing the self-muting audio connector of the type discussed herein. 
     Naturally, the above-described methods of the invention are particularly well adapted for use with the above-described apparatus of the invention. Similarly, the apparatus of the invention are well suited to perform the inventive methods described above. 
     Numerous other advantages and features of the present invention will become apparent to those of ordinary skill in the art from the following detailed description of the preferred embodiments, from the claims and from the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The preferred embodiments of the present invention will be described below with reference to the accompanying drawings where like numerals represent like steps and/or structures and wherein: 
         FIG. 1  is a side elevation view of a self-muting mono connector and jack in accordance with one preferred embodiment of the present invention; 
         FIG. 2  is another side elevation of the self-muting connector of  FIG. 1  in which the connector has been inserted into the jack; 
         FIG. 3   a  shows a cross-sectional view of the connector of  FIG. 1  taken along line  3   a - 3   a;    
         FIG. 3   b  shows a cross sectional view of the connector of  FIG. 2  taken along line  3   b - 3   b.    
         FIG. 4  depicts a perspective cross-sectional view of the connector of  FIG. 1  taken along line  3   a - 3   a;    
         FIG. 5  is a partial cut-away perspective view of the connector of  FIG. 1 ; 
         FIGS. 6   a  and  6   b  are cross-sectional views of a self-muting mono connector in accordance with still another preferred embodiment of the present invention; 
         FIGS. 7   a  through  7   e  are axial, bottom, top, right and left views of a spring switch for a self-muting connector in accordance with still another preferred embodiment of the present invention; 
         FIG. 8   a  is a side-elevation view of a self-muting connector in accordance with another preferred embodiment of the present invention, the connector using the spring switch of  FIGS. 7   a  through  7   e;    
         FIG. 8   b  shows a cross-sectional view of the connector of  FIG. 8   a  taken along line  8   b - 8   b.    
         FIG. 9   a  shows a cross-sectional and partial view of another self-muting audio connector in accordance with the invention; and 
         FIG. 9   b  shows a perspective view of a switch and an associated insulator for use with a self-muting audio connector in accordance with yet another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With joint reference to  FIGS. 1 ,  2 ,  3   a  and  3   b , a self-muting audio connector in accordance with a first preferred embodiment is shown and its operation illustrated therein. In particular, an inventive mono phone or “TS” (tip-sleeve) connector  10  is shown with a cylindrical, tubular outer sleeve  14  which is terminated at one of its ends by a tip  13  and at its other end by an enlarged threaded flange  17  onto which is threaded a connector body  15 . The tip  13  electrically is insulated from sleeve  14  by an annular insulator  16  and connected to a cylindrical inner rod  19  that is coaxial within the outer sleeve  14 . The inner rod  19  extends through (without contacting) flange  17  and is secured at the rear of the flange to an electrical terminal  21  which is insulated from flange  17  by an insulator  22 . A second electrical terminal  18  is affixed to flange  17  and thereby electrically connected to outer ground sleeve  14  and terminal  21  is electrically connected to tip  13  through rod  19  and insulated from outer sleeve  14 , flange  17 , and ground terminal  18 . 
     In its well known use to carry audio signals, TS connector  10  is coupled to a coaxial shielded cable (not shown) by soldering the cable ground conductor to ground terminal or lug  18  and the central signal-carrying conductor of the cable to terminal  21 . In this way, the tip  13  may be electrically coupled between two external circuits, such as a musical instrument and an operating amplifier, while sleeve  14  may be grounded. It is the fact that tip  13  is electrically coupled in this way that gives rise to the problems of the prior art set forth above in terms of screeching and possible damage to amplifiers and speakers. In order to avoid component damage and screeching, the present invention provides a spring-biased grounding switch  11  with a coil spring  23  disposed between the inner surface of tubular sleeve  14  and the outer surface of a signal conductor  19 . As shown, signal conductor  19  is preferably a rod shaped member, but it may take many other forms as it is merely a matter of design choice. When connector  10  is not inserted into an external jack, there is no force applied to protrusion  28 , see  FIGS. 1 and 3   a , and the spring bias of the coil spring  23  causes the contact between it and rod  19 . Since conductive spring  23  is also urged against the interior surface of sleeve  14 , tip  13  is grounded through rod  19 , switch  11  and sleeve  14 . In this way, whenever the phone connector is not in use (not inserted into a jack such as jack  33 ) the tip  13  is muted (grounded) and thus, there is no potential for generating a noise signal to be fed into the amplifier and broadcast through the speakers. 
     With continuing joint reference to  FIGS. 1-3   b , grounding switch  11  comprises a conductive coil spring  23  that is in substantially continuous contact with the inner surface of outer sleeve  14  and in selective contact with inner signal conductor  19 . Nonetheless, switch  11  is preferably neither affixed to sleeve  14  nor affixed to rod  19 . Rather, the spring-biasing force of switch coil  23  preferably urges protrusion  28  through an aperture  12  and, in the state shown in  FIGS. 1 and 3   a , urges itself against rod  19 . 
     With emphasis now to  FIGS. 2 and 3   b , in particular, in operation the connector  10  is inserted into jack  33  which includes a cylindrical receiving wall  34  having an inner diameter just slightly larger than the outer diameter of sleeve  14  and a tip contact and securing member  36 . While the force of coil  23  is sufficient to prevent longitudinal motion of switch  11  relative to sleeve  14  during normal use, it is also resilient enough to permit protrusion  28  to move radially inward when connector  10  is inserted into an external jack  33 . Such radially inward motion deforms coil  23  sufficiently to thereby automatically break the contact between coil  23  and rod  19 . This creates a gap G between coil  23  and rod  19 . When this occurs, a signal presented to terminal  21  is no longer shorted to ground and may pass to tip  13  and vice versa. This allows a normal electrical connection to be established between the connector and the device to which the connector is inserted. 
     Coil spring  23  is advantageously formed from a strip of conducting material, such as hardened spring steel, sized and shaped to bias itself (forming a physical and an electrical connection) against the inner wall of the cylindrical sleeve  14 . As best seen in  FIGS. 3   a  and  3   b , switch  11  is preferably generally “e-shaped” in cross-section. The coil spring spans the space between sleeve  14  and rod  19 , making electrical contact between the inner rod  19  and the grounded outer sleeve  14 . The protrusion  28  is preferably integrally formed with coil  23  by stamping a generally hemispherical detent into the inside of coil  23 . Protrusion  28  is, therefore, also preferably formed of the same piece of spring steel as coil  23 . In an alternative construction, protrusion  28  may be formed from one of many well know durable materials, regardless of whether they are conductive or non-conductive, such as nylon, plastic, brass, steel or the like. With such an alternative construction, coil  23  may include an aperture through with a portion of the protrusion may extend to enhance affixation. 
     The location of aperture  12  in the outer sleeve  14  determines the distance between the protrusion  28  and the tip  13 . By adjusting that distance a given connector can be either a make-before-break connector or a break-before-make connector. When the distance between the tip  13  and the protrusion  28  is such that the protrusion is depressed by the jack wall  34  before the tip  13  contacts the securing member  36 , the switch  11  will “break” before the tip “makes” connection with the securing member. When on the other hand, the distance between the tip  13  and the protrusion  28  is such that the protrusion is depressed by the jack wall  34  after the tip  13  contacts the securing member  36 , the tip  13  “makes” contact with the jack tip connector  36  before the switch  11  “breaks” (while the tip is still grounded). Whether a connector is designed to be a make-before-break or a break-before-make depends on the application and the electrical devices involved. The present invention is capable of providing either with only a slight change in the location of the protrusion aperture  12 . No other modification is required. 
     One particularly advantageous feature of the invention is that switch  11  is preferably not affixed either rod  19  or sleeve  14  by any conventional means such as a fastener or bonding material. This represents a significant advantage over the related art devices in that assembly of connector  10  is greatly simplified, less expensive and involves fewer components. In particular, switch  11  is preferably inserted into sleeve  14  such that protrusion  28  is aligned with aperture  12 , and then longitudinally slid into sleeve  14  until protrusion  28  engages with aperture  12 . In this way, the coil spring is self-aligning and does not require any precise location or matching parts during the manufacturing process. 
     With emphasis shifted to the cut-away, perspective views of  FIGS. 4 and 5 , one may still better appreciate the construction of the embodiment first shown in  FIG. 1 . In particular, one of ordinary skill will still better observe that switch  11  is preferably integrally formed and that protrusion  28  is preferably stamped from the coil to thereby form a hollow hemispherical member. It will, however, be appreciated that protrusion  28  may be formed into other shapes (for example, an elongated bar, or a cone) as long as aperture  12  is also changed to complement/accommodate such other shapes. As shown in these Figures, it has been found that coil  23  should be between about 0.4 cm (0.1587 inches) and about 1.0 cm (0.3968 inches) long provide the desired biasing force and physical stability (0.7 cm—0.2778 inches—being most preferred). 
     Another alternative embodiment of the inventive switch in accordance with the present invention is shown in cross-section and in operation in  FIGS. 6   a  and  6   b . As shown, mono self-muting connector  10 ″ is substantially similar to mono self-muting connector  10  of  FIGS. 1 through 5 . The primary difference between the two resides in the design of coil-spring switch  11 ″. In particular, coil spring  23 ″ preferably forms a closed loop with a portion thereof extending inwardly to permit selective contact with inner rod  19  as discussed above. Spring  23 ″ may be formed from a tubular piece of conductive material such as metal into which a portion has been stamped to form the inwardly extending portion. Additionally, protrusion  28  may be formed in any manner discussed above with respect to the spring  23 ″. Alternatively, spring  23 ″ may be formed as a closed loop in the sense that a portion of the coil overlaps but is not affixed together in the overlapping portion thereof. 
     With joint reference to  FIGS. 7   a  through  8   b , a self-muting audio connector in accordance with another preferred embodiment is shown and its operation illustrated therein. In particular, an inventive mono phone or “TS” (tip-sleeve) connector  10 ′″ is shown with a cylindrical, tubular outer sleeve  14 ′ which is terminated at one of its ends by a tip  13 ′ and at its other end by an enlarged threaded flange  17 ′ onto which is threaded a connector body  15 ′. The tip  13 ′ electrically is insulated from sleeve  14 ′ by an annular insulator  16 ′ and connected to a cylindrical inner rod  19 ″ that is coaxial within the outer sleeve  14 ′. The inner rod  19 ″ extends through (without contacting) flange  17 ′ and is secured at the rear of the flange to an electrical terminal  21 ′ which is insulated from flange  17 ′ by an insulator  22 ′. A second electrical terminal  18 ′ is affixed to flange  17 ′ and thereby electrically connected to outer ground sleeve  14 ′. Terminal  21 ′ is electrically connected to tip  13 ′ through rod  19 ″ and insulated from outer sleeve  14 ′, flange  17 ′, and ground terminal  18 ′. 
     In its use to carry audio signals, TS connector  10 ′″ is coupled to a coaxial shielded cable (not shown) by soldering the cable ground conductor to ground terminal or lug  18 ′ and the central signal-carrying conductor of the cable to terminal  21 ′. In this way, the tip  13 ′ may be electrically coupled between two external circuits, such as a musical instrument and an operating amplifier, while sleeve  14 ′ may be grounded. It is the fact that tip  13 ′ is electrically coupled in this way that gives rise to the problems of the prior art set forth above in terms of screeching and possible damage to amplifiers and speakers. In order to avoid component damage and screeching, this embodiment of the present invention provides a spring-biased grounding switch  11 ′″ disposed between the inner surface of tubular sleeve  14 ′ and the outer surface of a signal conductor  19 ″. As shown, signal conductor  19 ″ is preferably a rod shaped member, but it may take many other forms as it is merely a matter of design choice. When connector  10 ′″ is not inserted into an external jack, there is no force applied to protrusion  28 ′ and the spring bias of the spring switch  11 ′″ causes the contact between grounding sleeve  14 ′ and rod  19 ″. Since conductive spring  11 ′″ is urged against the interior surface of sleeve  14 ′, tip  13 ′ is grounded through rod  19 ″, switch  11 ′″ and sleeve  14 ′. In this way, whenever the phone connector is not in use (not inserted into a jack, such as jack  33  of  FIG. 1 ) the tip  13 ′ is muted (grounded) and thus, there is no potential for generating a noise signal to be fed into the amplifier and broadcast through the speakers. 
     With continuing joint reference to  FIG. 7   a  through  8   b , grounding switch  11 ′″ comprises a conductive conductor-engaging member  24 , a ground-sleeve engaging member  26  and a resilient (or spring biased) intermediate member  25 . The ground-sleeve engaging member  26  is in substantially continuous contact with the inner surface of outer sleeve  14 ′ and the conductor-engaging member  24  is in selective contact with inner signal conductor  19 ″. Nonetheless, switch  11 ′″ is preferably neither affixed to sleeve  14 ′ nor affixed to rod  19 ″. Rather, the spring-biasing force of member  25  preferably urges protrusion  28 ′ through an aperture  12 ′ and, in the state shown in  FIGS. 8   a  and  8   b , urges itself against rod  19 ″. Member  26  is preferably resilient and sized and shaped to snugly fit within the inside of sleeve  14 ′ and it may, optionally, include a number of slight outward protrusions P to aid with such engagement and to thereby provide additional stability. Also, member  24  preferably includes one or more contacts C that enable more precise and reliable selective electrical coupling with signal conductor  19 ″. 
     In operation the connector  10 ′″ is inserted into a jack which includes a cylindrical receiving wall having an inner diameter just slightly larger than the outer diameter of sleeve  14 ′ and a tip contact and securing member (such as member  36  of  FIG. 1 ). While the force of member  25  is sufficient to prevent longitudinal motion of switch  11 ′″ relative to sleeve  14 ′ during normal use, it is also resilient enough to permit protrusion  28 ′ to move radially inward when connector  10 ′″ is inserted into an external jack. Such radially inward motion deforms member  25  sufficiently to thereby automatically break the electrical contact between member  24  and rod  19 ″. This creates a gap (not shown) between spring conductor-engaging member  24  and rod  19 ″. When this occurs, a signal presented to terminal  21 ′ is no longer shorted to ground and may pass to tip  13 ′ and vice versa. This allows a normal electrical connection to be established between the connector and the device to which the connector is inserted. 
     Spring switch  11 ′″ is advantageously formed from a strip of conducting material, such as hardened spring steel, (or Beryllium Copper) sized and shaped to bias itself (forming a physical and an electrical connection) against the inner wall of the cylindrical sleeve  14 ′. As best seen in  FIGS. 7   a  and  8   b , members  24  and  26  are preferably elongated, generally “c-shaped” in cross-section and are respectively aligned along parallel axes. By contrast, member  25  is preferably a slightly curved strip that is angled relative to the parallel axes. Member  24  may also be described as being generally “horseshoe-shaped,” by which is meant the member as shown in  FIGS. 7   a  through  8   b  and also referred to above as generally “c-shaped.” The spring  11 ′″ spans the space between sleeve  14 ′ and rod  19 ″, making electrical contact between the inner rod  19 ″ and the grounded outer sleeve  14 ′. The protrusion  28 ′ is preferably integrally formed with the spring by stamping a generally hemispherical detent into the inside of spring  11 ′″. Protrusion  28 ′ is, therefore, also preferably formed of the same piece of spring as the rest of switch  11 ′″. In an alternative construction, protrusion  28 ′ may be formed from one of many well know durable materials, regardless of whether they are conductive or non-conductive, such as nylon, plastic, brass, steel or the like. With such an alternative construction, member  24  may include an aperture through which a portion of the protrusion may extend to enhance affixation. 
     The location of aperture  12 ′ in the outer sleeve  14 ′ determines the distance between the protrusion  28 ′ and the tip  13 ′. By adjusting that distance a given connector can be either a make-before-break connector or a break-before-make connector. When the distance between the tip  13 ′ and the protrusion  28 ′ is such that the protrusion is depressed by the jack wall before the tip  13 ′ contacts the securing member, the switch  11 ′″ will “break” before the tip “makes” connection with the securing member. When, on the other hand, the distance between the tip  13 ′ and the protrusion  28 ′ is such that the protrusion is depressed by the jack wall after the tip  13 ′ contacts the securing member, the tip  13 ′ “makes” contact with the jack tip connector before the switch  11 ′″ “breaks” (while the tip is still grounded). Whether a connector is designed to be a make-before-break or a break-before-make depends on the application and the electrical devices involved. The present invention is capable of providing either with only a slight change in the location of the protrusion aperture  12 ′. No other modification is required. 
     One particularly advantageous feature of the invention is that switch  11 ′″ is preferably not affixed either rod  19 ″ or sleeve  14 ′ by any conventional means such as a fastener or bonding material. This represents a significant advantage over the related art devices in that assembly of connector  10 ′″ is greatly simplified, less expensive and involves fewer components. In particular, switch  11 ′″ is preferably inserted into sleeve  14 ′ such that protrusion  28 ′ is aligned with aperture  12 ′, and then longitudinally slid into sleeve  14 ′ until protrusion  28 ′ engages with aperture  12 ′. In this way, the spring is self-aligning and does not require any precise location or matching parts during the manufacturing process. 
     With emphasis shifted to the cut-away, view of  FIG. 8   b , one may still better appreciate the construction of the embodiment first shown in  FIGS. 7   a  through  8   b . In particular, one of ordinary skill will still better observe that switch  11 ′″ is preferably integrally formed and that protrusion  28 ′ is preferably stamped to thereby form a hollow hemispherical member. It will, however, be appreciated that protrusion  28 ′ may be formed into other shapes (for example, an elongated bar, or a cone) as long as aperture  12 ′ is also changed to complement/accommodate such other shapes. During manufacturing, switch  11 ′″ is preferably stamped from a beryllium-copper sheet that preferably has a thickness of between about 0.2 mm (0.0079 inches) and about 0.4 mm (0.0157 inches) (with about 0.3 mm—0.0118 inches—being most preferred) to ensure that intermediate member  25  can provide the desired biasing force and physical stability. 
     With reference to  FIG. 9   a , a self-muting audio connector in accordance with another preferred embodiment is shown and its operation illustrated therein. In particular, an inventive mono phone or “TS” (tip-sleeve) connector is shown with a cylindrical, tubular outer sleeve  14 ′ of the type described above, the relevant conventional details of which also apply to this embodiment. The tip electrically is insulated from sleeve  14 ′ by an annular insulator  16 ″ and connected to a cylindrical inner rod  19 ″ that is coaxial within the outer sleeve  14 ′. In its use to carry audio signals, TS connector is coupled to a coaxial shielded cable (not shown) by electrical communication with the cable ground conductor to ground terminal or lug and the central signal-carrying conductor of the cable to terminal. 
     This embodiment of the present invention provides a spring-biased grounding switch  11   a  disposed between the inner surface of tubular sleeve  14 ′ and the outer surface of a signal conductor  19 ″. When the connector is not inserted into an external jack, there is no force applied to protrusion  28 ″ and the spring bias of the spring switch  11   a  causes the contact between grounding sleeve  14 ′ and rod  19 ″. Since conductive spring  11   a  is urged against the interior surface of sleeve  14 ′, the tip is grounded through rod  19 ″, switch  11   a  and sleeve  14 ′. In this way, whenever the phone connector is not in use (not inserted into a jack, such as jack  33  of  FIG. 1 ) the tip is muted (grounded) and thus, there is no potential for generating a noise signal to be fed into the amplifier and broadcast through the speakers. 
     With continuing reference to  FIG. 9   a , grounding switch  11   a  comprises a conductive conductor-engaging member  24 ′, a ground-sleeve engaging member  26 ′ and a resilient (or spring biased) intermediate member  25 ′. The ground-sleeve engaging member  26 ′ is in substantially continuous contact with the inner surface of outer sleeve  14 ′ and the conductor-engaging member  24 ′ is in selective contact with inner signal conductor  19 ″. Nonetheless, switch  11   a  is preferably neither affixed to sleeve  14 ′ nor affixed to rod  19 ″ with any components or bonding materials. Rather, the spring-biasing force of member  25 ′ preferably urges protrusion  28 ″ through an aperture  12 ″ and, in the state shown in  FIG. 9   a , urges itself against rod  19 ″. Member  26 ′ is preferably resilient and sized and shaped to snugly fit within the inside of sleeve  14 ′ and it may, optionally, include one or more outward protrusions P′ snugly received within a complementary aperture  12 ″ to aid with such engagement and to thereby provide additional stability against rotational movement. Optionally, member  24 ′ may include one or more contacts C′ that enable more precise and reliable selective electrical coupling with signal conductor  19 ″. It has been discovered that reliable operation of the inventive switch over long periods of time and many connector-insertion/removal cycles cannot be expected without some means of radically-reducing/substantially eliminating rotational motion of the switch  11   a  about the axis defined by member  19 ″. Accordingly, some anti-rotation means (such as protrusion/aperture P′/ 12 ″) is important for achieving switch reliability that approaches that expected of conventional TS connectors. 
     In operation the connector is inserted into a jack which includes a cylindrical receiving wall having an inner diameter just slightly larger than the outer diameter of sleeve  14 ′ and a tip contact and securing member (such as member  36  of  FIG. 1 ). Member  25 ′ is resilient enough to permit protrusion  28 ″ to move radially inward when the connector is inserted into an external jack. Such radially inward motion deforms member  25 ′ sufficiently to thereby automatically break the electrical contact between member(s)  24 ′ and rod  19 ″. This creates a gap (not shown) between spring conductor-engaging member  24 ′ and rod  19 ″. When this occurs, a signal is no longer shorted to ground and may pass to the tip and vice versa. This allows a normal electrical connection to be established between the connector and the device to which the connector is inserted. 
     Spring switch  11   a  is advantageously/preferably stamped from a strip of conducting material, such as hardened spring steel, sized and shaped to bias itself (forming a physical and an electrical connection) against the inner wall of the cylindrical sleeve  14 ′. Member  24 ′ may be described as being generally “horseshoe-shaped” and/or generally “c-shaped.” The protrusion  28 ″ is preferably integrally formed with the spring by stamping a smoothly rounded detent into the inside of spring  11   a . Protrusion  28 ″ is, therefore, also preferably formed of the same piece of spring as the rest of switch  11   a . In an alternative construction, protrusion  28 ″ may be formed from one of many well know durable materials, regardless of whether they are conductive or non-conductive, such as nylon, plastic, brass, steel or the like. With such an alternative construction, member  24 ′ may include an aperture through which a portion of the protrusion may extend to enhance affixation. 
     The location of aperture  12 ″ in the outer sleeve  14 ′ determines the distance between the protrusion  28 ″ and the tip. By adjusting that distance a given connector can be either a make-before-break connector or a break-before-make connector as described above. The present invention is capable of providing either with only a slight change in the location of the protrusion aperture  12 ″. No other modification is required. 
     One particularly advantageous feature of the invention is that switch  11   a  is preferably not affixed either rod  19 ″ or sleeve  14 ′ by any conventional means such as a fastener or bonding material. This represents a significant advantage over the related art devices in that assembly of the inventive connector is greatly simplified, less expensive and involves fewer components. In particular, switch  11   a  is preferably inserted into sleeve  14 ′ such that protrusion  28 ″ is aligned with aperture  12 ′ and such that protrusion P′ is aligned with aperture  12 ″; then the unit is longitudinally slid into sleeve  14 ′ until protrusion  28 ″ extends through aperture  12 ′ and until protrusion P′ firmly snaps into aperture  12 ″. In this way, the spring is a self-aligning, anti-rotation member and does not require any precise location or matching parts during the manufacturing process. 
     One of ordinary skill will still better observe that switch  11   a  is preferably integrally formed and that protrusions  28 ″ and P′ are preferably stamped. It will, however, be appreciated that protrusion  28 ″ may be formed into various shapes (for example, an elongated bar, or a cone) as long as aperture  12 ″ is also changed to complement/accommodate such other shapes. During manufacturing, switch  11   a  is preferably stamped from a beryllium-copper sheet that preferably has a thickness of between about 0.2 mm (0.0079 inches) and about 0.4 mm (0.0157 inches) (with about 0.3 mm—0.0118 inches—being most preferred) to ensure that intermediate member  25 ′ can provide the desired biasing force and physical stability. 
     With reference to  FIG. 9   b , a switch for use with a self-muting audio connector in accordance with another preferred embodiment is shown. In particular, a switch is shown for an inventive mono phone or “TS” (tip-sleeve) connector of the type described above, the relevant details as shown in, for example  FIG. 9   a , also apply to this embodiment. The tip electrically is insulated from sleeve  14 ′ by an annular insulator  16 ″ and connected to a cylindrical inner rod  19 ″ that is coaxial within the outer sleeve  14 ′. In its use to carry audio signals, TS connector is coupled to a coaxial shielded cable (not shown) by electrical communication with the cable ground conductor to ground terminal or lug and the central signal-carrying conductor of the cable to terminal. 
     This embodiment of the present invention provides a spring-biased grounding switch  11   a ′ to be disposed between the inner surface of tubular sleeve  14 ′ and the outer surface of a signal conductor  19 ″. When the connector is not inserted into an external jack, there is no force applied to protrusion  28 ′″ and the spring bias of the spring switch  11   a ′ causes the contact between grounding sleeve  14 ′ and rod  19 ″. Since conductive spring  11   a ′ is urged against the interior surface of sleeve  14 ′, the tip is grounded through rod  19 ″, switch  11   a ′ and sleeve  14 ′. In this way, whenever the connector is not in use (not inserted into a jack, such as jack  33  of  FIG. 1 ) the tip is muted (grounded) and thus, there is no potential for generating a noise signal to be fed into the amplifier and broadcast through the speakers. 
     With continuing reference to  FIG. 9   b , grounding switch  11   a ′ comprises a conductive conductor-engaging member  24 ″, a ground-sleeve engaging member  26 ″ and a resilient (or spring biased) intermediate member  25 ″. The ground-sleeve engaging member  26 ″ is in substantially continuous contact with the inner surface of outer sleeve  14 ′ and the conductor-engaging member  24 ″ is in selective contact with inner signal conductor  19 ″. Nonetheless, switch  11   a ′ is preferably neither affixed to sleeve  14 ′ nor affixed to rod  19 ″ with any components or bonding materials. Rather, the spring-biasing force of member  25 ″ preferably urges protrusion  28 ′″ through a corresponding aperture and urges itself against rod  19 ″. Member  26 ″ is preferably resilient and sized and shaped to snugly fit within the inside of sleeve  14 ′ and it may, optionally, include one or more outward protrusions P″ snugly received within a complementary aperture to aid with such engagement and to thereby provide additional stability against rotational movement. Optionally, member  24 ″ may include one or more contacts C″ that enable more precise and reliable selective electrical coupling with signal conductor  19 ″. It has been discovered that reliable operation of the inventive switch over long periods of time and many connector-insertion/removal cycles cannot be expected without some means of radically-reducing/substantially eliminating rotational motion of the switch  11   a ′ about the axis defined by member  19 ″. Accordingly, some anti-rotation means (such as a protrusion/aperture aperture arrangement) is important for achieving switch reliability that approaches that expected of conventional TS connectors. 
     In operation, the connector is inserted into a jack which includes a cylindrical receiving wall having an inner diameter just slightly larger than the outer diameter of sleeve  14 ′ and a tip contact and securing member (such as member  36  of  FIG. 1 ). Member  25 ″ is resilient enough to permit protrusion  28 ′″ to move radially inward when the connector is inserted into an external jack. Such radially inward motion deforms member  25 ″ sufficiently to thereby automatically break the electrical contact between member(s)  24 ″ and rod  19 ″. This creates a gap (not shown) between spring conductor-engaging member  24 ″ and rod  19 ″. When this occurs, a signal is no longer shorted to ground and may pass to the tip and vice versa. This allows a normal electrical connection to be established between the connector and the device to which the connector is inserted. 
     Spring switch  11   a ′ is advantageously/preferably stamped from a strip of conducting material, such as hardened spring steel, sized and shaped to bias itself (forming a physical and an electrical connection) against the inner wall of the cylindrical sleeve  14 ′. Member  24 ″ may be described as being generally “horseshoe-shaped” and/or generally “c-shaped.” The protrusion  28 ′″ is preferably integrally formed with the spring by stamping a smoothly rounded detent into the inside of spring  11   a ′. Protrusion  28 ′″ is, therefore, also preferably formed of the same piece of spring as the rest of switch  11   a ′. In an alternative construction, protrusion  28 ′″ may be formed from one of many well know durable materials, regardless of whether they are conductive or non-conductive, such as nylon, plastic, brass, steel or the like. With such an alternative construction, member  24 ″ may include an aperture through which a portion of the protrusion may extend to enhance affixation. 
     The location of aperture  12 ″ in the outer sleeve  14 ′ determines the distance between the protrusion  28 ′″ and the tip. By adjusting that distance a given connector can be either a make-before-break connector or a break-before-make connector as described above. The present invention is capable of providing either with only a slight change in the location of the protrusion aperture  12 ″. No other modification is required. 
     One particularly advantageous feature of the invention is that switch  11   a ′ is preferably not affixed either rod  19 ″ or sleeve  14 ′ by any conventional means such as a fastener or bonding material. This represents a significant advantage over the related art devices in that assembly of the inventive connector is greatly simplified, less expensive and involves fewer components. In particular, switch  11   a ′ is preferably inserted into sleeve  14 ′ such that protrusion  28 ′″ is aligned with aperture  12 ′ and such that protrusion P″ is aligned with aperture  12 ″; then the unit is longitudinally slid into sleeve  14 ′ until protrusion  28 ′″ extends through aperture  12 ′ and until protrusion P″ firmly snaps into aperture  12 ″. In this way, the spring is a self-aligning, anti-rotation member and does not require any precise location or matching parts during the manufacturing process. 
     One of ordinary skill will still better observe that switch  11   a ′ is preferably integrally formed and that protrusions  28 ′″ and P″ are preferably stamped. It will, however, be appreciated that protrusion  28 ′″ may be formed into various shapes (for example, an elongated bar, or a cone) as long as aperture  12 ″ is also changed to complement/accommodate such other shapes. During manufacturing, switch  11   a ′ is preferably stamped from a beryllium-copper sheet that preferably has a thickness of between about 0.2 mm (0.0079 inches) and about 0.4 mm (0.0157 inches) (with about 0.3 mm—0.0118 inches—being most preferred) to ensure that intermediate member  25 ″ can provide the desired biasing force and physical stability. 
     While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to encompass the various modifications and equivalent arrangements included within the spirit and scope of the appended claims. With respect to the above description, for example, it is to be realized that the optimum dimensional relationships for the parts of the invention, including variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the appended claims. Therefore, the foregoing is considered to be an illustrative, not exhaustive, description of the principles of the present invention.

Technology Classification (CPC): 7