The present invention relates to a composition comprising: a copolyester of polyethylene terephthalate and a dicarboxylic acid or its ester equivalent, and not more than 100 microequivalents per gram of said copolyester of an anhydride selected from the class consisting of succinic, glutaric, benzoic, maleic and phthalic anhydride, said composition having a CEG content greater than about 25 microequivalents per gram and an IV greater than about 0.65. The present invention also concerns a method of making a composition having reduced caustic stress cracking, comprising: reacting terephthalic acid or its ester equivalent and another dicarboxylic acid with ethylene glycol by esterification followed by polycondensation to make a polyethylene terephthalate copolyester; adding at the end of said polycondensation not more than 100 microequivalents per gram based on said copolyester of an anhydride selected from the class consisting of succinic, glutaric, maleic, benzoic, and phthalic anhydride, said composition having a CEG content greater than about 25 microequivalents per gram.

1) Field of the Invention
The present invention concerns a copolyester resin having a high number of carboxyl end groups (CEG) and a method of making such a resin. Specifically, the copolyester is polyethylene terephthalate and a dicarboxylic acid, along with an anhydride resulting in a high content CEG resin characterized by reduced stress cracking. The copolyester is employed for a packaging resin useful in such as a soft drink beverage bottle, for example, with significantly improved stress cracking resistance. More particularly, the present invention also concerns a method of producing the copolyester by introducing at the end of polycondensation, one or more of phthalic anhydride, glutaric anhydride, benzoic anhydride, maleic anhydride or succinic anhydride in an amount sufficient to significantly reduce the caustic stress cracking.
2) Prior Art
Copolyester bottle resin is well known in the art. Typical copolyester bottle resins employ polyethylene terephthalate (PET) and a dicarboxylic acid such as isophthalic acid. The dicarboxylic acid was added to adjust the rate of crystallization of PET by decreasing it, in order to obtain clear bottle/jar preforms, which are stretch-blow molded into containers, such as soft drink bottles. If a crystallization retarding agent is not employed, crystallization of the preform occurs resulting in a hazy preform and a hazy bottle/jar. However, if too much dicarboxylic acid is used, the physical properties of copolyester resin are significantly weaker than PET resin.
Later, it was observed that an increase in isophthalic acid improved barrier properties of the bottle/jar of the copolyester resin. A balance in the amount of dicarboxylic acid employed was necessary to add a sufficient amount to adjust the rates of crystallization to avoid haze and improve the barrier properties, but avoid significantly weakening the copolyester (compared to PET resin).
It was then realized that the smaller (e.g. 20 ounce) soft drink beverage bottles, which have a larger volume/surface area ratio, require a higher barrier property than (2 liter) bottles. Thus the resin composition for smaller soft drink bottles contains more isophthalic acid to improve the barrier properties, than larger bottles.
The increase in isophthalic acid in copolyester resins has led to somewhat weaker physical properties especially for the smaller soft drink bottle. This weakening is observed in bottle failure from stress cracking, a problem not known before the significant increase in isophthalic acid. Stress cracking occurs over time, generally in the base of the bottle, causing a bottle under pressure with carbonated liquid to either lose pressure, or in the extreme, burst. Stress cracking can be initiated by the alkaline lubricants used in the bottle filling lines, or by the residues of alkaline cleaning solutions on store shelves.
U.S. Pat. No. 3,051,212 to Daniels; U.S Pat. No. 4,016,142 to Alexander et al.; and U.S. Pat. No. 4,442,058 to Griffith et al. teach reducing the amount of CEG present in polyester in order to increase the hydrolytic stability. More specifically, these references recognize that an increase in the CEG content for polyester, decreases the hydrolytic stability of the polymer, such that the IV stability during drying decreases, i.e., the IV drops during drying.
U.S. Pat. No. 4,328,593 to Duh discloses an amorphous polyester which has an optimal level of CEG to reduce the reaction time in a solid state polymerization vessel. Reducing the reaction time in a solid state polymerization (SSP) vessel minimizes chemical instability and deleterious polymerization byproducts. The optimum amount is defined as the amount of CEG content in the amorphous polymer necessary to react with some of the HEG (hydroxyl end groups) to favor the chemical reaction rate.
Although this reference teaches having an optimal amount of CEG during processing of the polymer, it teaches away from having an excess of CEG that remain in the resin, because such an excess would increase the SSP residence time (see FIG. 2 of the Duh reference). There is no disclosure that the polyester resin (of the preform or the blown bottle) contains a high CEG content. Polyester resin is polymer which has been solid state polymerized.
U.S. Pat. No. 4,361,681 to Bernhardt discloses PET having a reduced acetaldehyde generation rate. The PET is reacted with succinic or phthalic anhydride. The examples disclose that the anhydride was introduced by physically precoating the resin (which had been solid state polymerized) just prior to extrusion into bottle preforms. There is no disclosure relating to copolyesters or the CEG content.
U.S. Pat. No. 4,578,437 to Light et al. discloses copolyesters useful for bottle resin. Specifically, this reference discloses PET made from terephthalic acid and ethylene glycol with isophthalic acid to create the copolyester. This reference discloses its copolyesters have improved carbon dioxide barrier properties for soft drinks.
U.S. Pat. No. 5,362,844 to Kerpes et al. discloses an amorphous PET resin useful for making bottles, which has an optimum CEG content and after the PET has been SSP""d the resulting resin has a low acetaldehyde content. It is known that the CEG content in an amorphous polyester will be significantly reduced during solid state polymerization. There is no disclosure that the polyester resin, preform, or the bottle contains a high CEG content.
U.S. Pat. Nos. 5,912,307 and 6,011,132 to Paschke et al. discloses a copolyester of PET. naphthalate and/or isophthalate to increase the crystallinity of the copolyester article thereby exhibiting high carbon dioxide barrier properties.
U.S. Pat. No. 5,925,710 to Wu et al., teaches copolyesters having 2.5 weight percent of isophthalic acid. These copolyesters are useful for bottle resin. This reference discloses the amount of CEG in the amorphous resin, but does not disclose the amount of CEG in the preform or bottle (i.e., after solid state polymerization).
PCT published application WO 00/49065 to DuPont discloses a PETxe2x80x94isophthalic acid comonomer having a very high CEG content which was solid state polymerized for up to 24 hours. The IV never exceeded 0.639 because the HEG were essentially depleted, limiting further molecular weight enhancement. This reference also teaches that low CEG content is better for producing high IV""s (see Examples 2 and 5).
To increase the SSP rate, an optimum amount of CEG in the amorphous polymer is desired as taught by the Duh patent. At the end of SSP, it is no longer desired to have free CEG within the resin and Duh states that excess CEG increase, not decrease, the SSP reaction time. It is also known that an excess of CEG in the resin has a detrimental hydrolytic stability effect (as taught by Daniels, Alexander, et al. or Griffith et al.) thus weakening and lowering its IV and producing a product having lower physical properties, compared with the physical properties obtained from a product having a higher IV. None of the references set forth above discloses stress cracking as a problem and therefore none of the references has a solution for reducing or preventing stress cracking.
It is a chief aim and object of the present invention to provide a copolyester capable of being stretch-blow molded into a bottle or jar container which exhibits improved stress cracking resistance over conventionally available polyester or copolyester resin compositions.
Likewise, it is another object of the present invention to manufacture a copolyester resin capable of being stretch-blow molded into bottles or jar containers, by making the copolyester with a high CEG content after SSP.
The resin of the present invention, directed to a copolyester of PET and at least one dicarboxylic acids such as, for example, isophthalic acid or naphthoic acid has reduced stress cracking i.e. improved stress cracking performance when small amounts of phthalic, glutaric, benzoic, maleic and/or succinic anhydride are incorporated into the copolyester. The anhydride reacts with the HEG in the copolyester to produce CEG. It is believed that these higher CEG resins neutralize the alkaline lubricants that contact the base of the bottle. Therefore, the incorporation of anhydride into the resin to convert some of the HEG to CEG drastically reduces the stress cracking occurring in soft drink bottles, for example. The stress cracking is exemplified when a bottle bursts, discharging its contents.
In the broadest sense, the present invention refers to a copolyester composition consisting of PET and dicarboxylic acid such as isophthalic acid or naphthoic acid, which has been solid stated, and wherein the copolyester contains up to 20 wt % of the dicarboxylic acid and has a CEG content greater than 25 microequivalents per gram. Solid state resin means a resin having an IV greater than about 0.65. More preferably, the copolyester compositions of the present invention have an IV greater than about 0.70. Most preferably, the copolyester compositions of the present invention have an IV greater than about 0.75. The broad scope of the present invention contemplates a CEG value of 25 microequivalents per gram, a preferred range is 30 microequivalents per gram, and a most preferred range is 40 microequivalents per gram.
In the broadest sense, the present invention also comprises a method of manufacturing a resin composition having improved (reduced) stress cracking by producing a copolymer of PET and dicarboxylic acid such as isophthalic acid or naphthoic acid, and adding at least one of phthalic anhydride, glutaric anhydride, benzoic anhydride, maleic anhydride or succinic anhydride as a late addition in the melt polymerization process, and solid state polymerizing the composition.
Polyethylene terephthalate (PET) is conventionally made by reacting either dimethyl terephthalate or terephthalic acid with ethylene glycol, for example, via an esterification reaction, followed by a polycondensation reaction. When making PET, either in a batch or continuous process, the reactions can be driven to near completion, yielding PET having up to 3 weight percent of diethylene glycol and other byproducts. Pet is meant to include small amounts of byproducts.
Conventional continuous production of PET is well known in the art and comprises reacting terephthalic acid and ethylene glycol at a temperature of approximately 200xc2x0 to 250xc2x0 C. forming monomer and water. Because the reaction is reversible, the water is continuously removed, driving the reaction to the production of monomers. Next the monomers undergo polycondensation reaction in vacuum conditions at a temperature of approximately 250xc2x0 to 290xc2x0 C. to form polymer having an IV of about 0.4 to 0.6. During the esterification reaction, no catalyst is needed. However, in the polycondensation reaction, a catalyst such as antimony or titanium is necessary.
PET is also made in batch and continuous processes from the reaction of the ester-dimethyl terephthalate and ethylene glycol, at a reaction temperature of approximately 190xc2x0 to 230xc2x0 C. forming alcohol (methanol) and monomer. This esterification reaction is reversible and the alcohol must be continuously removed, driving the reaction to the production of monomer. In the reaction of dimethyl terephthalate and ethylene glycol, catalysts such as manganese, zinc, cobalt or other conventional catalyst are employed. Next, the monomer undergoes a polycondensation reaction at the conditions stated above to form a polymer having an IV of about 0.4 to 0.6. Making a copolyester with PET and dicarboxylic acid (to reduce the crystallization rate and improve its barrier properties) merely requires the substitution of the acid or its ester equivalent, for example, to also undergo an esterification (either in a continuous or a batch process) followed by a polycondensation reaction, simultaneously with the making of PET.
Resins containing up to 20 wt % of the dicarboxylic acid are useful in forming bottles or jar containers as is known in the art. Suitable diacids may be aliphatic, alicyclic, or aromatic dicarboxylic acids such as isophthalic acid, 1,4-cyclohexanedicarboxylic acid; 1,3-cyclohexanedicarboxylic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, 1,12-dodecanedioic acid; 2,6-naphthalenedicarboxylic acid, bibenzoic acid, oxalic acid, malonic acid. pimelic acid, suberic acid, azalaic acid, maleic acid, fumaric acid, phthalic acid, hemimellitic acid, trimellitic acid, trimesic acid, or mixtures of these and their equivalents. It is often preferred to use a functional acid derivative equivalent such as dimethyl, diethyl, or dipropyl ester of the dicarboxylic acid. Bottle resin, including the present invention, typically contains 1.5-20 wt. %, based on the weight of the resin, of isophthalic acid as the crystallization retarder and barrier improvement additive.
In the making of bottle preforms and plastic bottles from the preforms, it is often desired to produce the cleanest, clearest polymer. Accordingly, the less additives employed, the clearer the polymer produced. On the other hand, it is sometimes desirable to make a colored plastic bottle or bottles with other desired characteristics, and thus the use of a variety of conventionally known additives is also within the scope of the present invention. Accordingly, various pigments, dyes, fillers, branching agents, and other typical agents may be added to the polymer generally during or near the end of the polycondensation reaction. The exact desired additives and the place on introduction in the reaction does not form a part of this invention and this technology is well known in the art. Any conventional system may be employed and those skilled in the art can pick and choose among the various systems of introduction of additives to achieve the desired result.
Typical additives to increase the CEG level of the copolyester are phthalic, glutaric, benzoic, maleic and/or succinic anhydride. The ester and acid equivalents of these anhydrides are not desirable because a catalyst would be necessary for these to react with the resin. For example, if dimethyl phthalate was employed, it would not react with the copolyester resin at the end of polycondensation without the presence of a catalyst. Using the anhydrides to increase CEG eliminates the need for any catalyst. An additional advantage of using anhydrides is that no byproducts are generated by their reaction with HEG. Reaction of esters would generate alcohols and reaction of diacids would generate water. The presence of these materials would have a deleterious effect on resin quality. The amount of anhydride typically employed in the present invention ranges from about 10-100 microequivalents, and preferably 20 to 50 microequivalents per gram of the copolyester.
With the process of the present invention, it is not desirable to add the anhydride agents to the reaction vessel in such a manner that the anhydride reacts with all of the HEG in the polyester and no HEG are available for polymerization, i.e., adding excessive anhydride during esterification. For polymerization to occur either in the polycondensation reactor or in the SSP reactor, or both, one of two reactions must occur, namely:
xe2x80x94OH+xe2x80x94COOHxe2x86x92H2O,xe2x80x83xe2x80x83(1)
and
xe2x80x94OH+xe2x80x94OHxe2x86x92glycol.xe2x80x83xe2x80x83(2)
The first reaction is a slower reaction but water is easily separated from the reaction vessel. The second reaction is faster but the glycol is harder to separate from the reactor. From these two equations, it is easy to see that if the anhydride reacts with all of the hydroxyls in the copolyester, there will be no more OH groups (bydroxyl end groups) available for polymerization. Accordingly, the reaction will stop.
In order to obtain a resin having an abundance of carboxyl end groups, it is clear that the anhydrides of the present invention must be added at the end of polycondensation or later. With the present invention, it is preferred that anhydride is introduced late in the melt polymerization process such as late in the polycondensation process just prior to solid state polymerization. Specifically, the anhydride could be added near the end of the polycondensation polymerization process such that it has at least one to two minutes reaction time before the copolymer is extruded, cooled and cut into chip.
If a batch process is used, there are two reactor vessels, one for esterification, which is generally at atmospheric pressure and at a temperature of from about 180xc2x0 to 250xc2x0 C. Then the esterified reaction products are transferred to a polycondensation vessel, which is operated at a higher temperature, generally between 250xc2x0 to 290xc2x0 C. and at a vacuum. Accordingly, the anhydride of the present invention would be added to copolyester resin at the end of polycondensation reaction, just after the vacuum is permitted to attain atmospheric pressure, such that it reacts with the copolymer for at least one to two minutes before it is extruded, cooled and cut into chip.
If a continuous process is used, anhydride is added to the transfer pipe between the final polymerizer and the die that forms the strands that are cooled and cut into chips. Anhydride added at this point has a mixing time of about one to two minutes (the residence time) in the piping as it flows from the high polymerizer vessel to the die where it is extruded, then cooled and cut into chip. The amount of anhydride incorporated at this point in the process can be controlled to give an optimum CEG/HEG ratio sufficient for solid state polymerization, i.e., some residual HEG, as well as an increased CEG level in the final polyester resin. Typically, 10-100 microequivalents of the anhydride is employed per gram of the resin. Preferably, 20-50 microequivalents of anhydride is used per gram of the copolyester resin.
After polycondensation, the copolyester is extruded, cooled and cut into chip as conventionally known in the art. The chip is ready for SSP, where the chip IV is generally increased from about 0.4-0.6 to 0.65-0.90. For a 0.6 I.V., a total of about 110 end groups are present. There are about 80 HEG (microequivalents per gram) and about 30 CEG (microequivalents per gram) present from a typical melt phase polymerization. With the addition of 30 to 40 microequivalents per gram of succinic anhydride corresponding to about 0.3 to 0.4 weight per gram, such additive would convert 30 to 40 HEG to CEG yielding 60 to 70 CEG with the same total of 110 end groups in the amorphous resin prior to SSP. The SSP reaction to an IV of 0.80 reduces the total end groups to about 75, with 45 to 55 being CEG and 20 to 30 being HEG.
CEG
The CEG value of a polymer is determined by dissolving a sample of the polymer in reagent grade benzyl alcohol and titrating to the purple end point of phenol red indicator with 0.03 N sodium hydroxide/benzyl alcohol solution. The results are reported in microequivalents sodium hydroxide per gram of the sample.
DEG
The DEG (diethylene glycol) content of the polymer is determined by hydrolyzing the polymer with an aqueous solution of ammonium hydroxide in a sealed reaction vessel at 220xc2x15xc2x0 C. for approximately two hours. The liquid portion of the hydrolyzed product is then analyzed by gas chromatography. The gas chromatography apparatus is a FID Detector (HP5890, HP7673A) from Hewlett Packard. The ammonium hydroxide is 28 to 30% by weight ammonium hydroxide from Fisher Scientific and is reagent grade.
IV
Intrinsic viscosity (IV) is determined by mixing 0.2 grams of an amorphous polymer composition with twenty milliliters of dichloroacetic acid at a temperature of 25xc2x0 C. using a Ubbelhode viscometer to determine the relative viscosity (RV). RV is converted to IV using the ISO certificated equation: IV=[(RVxe2x88x921)xc3x970.6907]+0.63096
Stress Cracking
The resistance of a bottle to stress cracking is determined at an accelerated test using sodium hydroxide to induce stress cracking. Twenty-five bottles are used as a set. The bottles are filled with water at 22xc2x0 C. to a target net contents (2 liter bottles would contain 2 liters of water). Each bottle is pressurized with compressed air to an equivalent internal pressure of 531 kPa (77 psi). Five minutes after pressurization, each bottle is placed in individual pockets containing a 0.2 percent sodium hydroxide solution at 22xc2x0 C. The solution covers the base of the bottle up to the top of the strap of the bottle. The time for failure of each bottle is recorded. Failure is defined as a burst or slow leak as evidenced by a drop in the level of water in the bottle. The test is completed after four hours. Results are reported as the number of failures in a four hour period, and as the average time for thus said to fail.
Haze
The haze of the preforms was measured with a Hunter Lab ColorQuest II instrument. The haze is defined as the percent of diffused light to total transmitted light.
After solid state polymerization, the resin of the present invention is typically heated and extruded into preforms. Each preform for a 20 ounce soft drink bottle, for example, employs about 26.8 grams of the resin. The preform is then heated to about 100-120xc2x0 C. and blown-molded into a 20 ounce contour bottle at a stretch ratio of about 12.5. The stretch ratio is the stretch in the radial direction times the stretch in the length (axial) direction. Thus if a preform is blown into a bottle, it may be stretched about two times its length and stretched about six times is diameter giving a stretch ratio of twelve (2xc3x976). Since the bottle size is fixed, different preform sizes can be used for obtaining different stretch ratios. The preforms tested in the examples for the 20 ounce contour bottles have from 5.0 to 5.4 grams of resin in the base. More specifically, the weight of the bottle base was primarily from 5.2 to 5.3 grams. Most stress cracking occurs in the base of the bottle. Testing for stress cracking should be completed with bottles having a base of about the same thickness (i.e., the same amount of resin) to give comparable results.

Copolyester with high carboxyl end groups and a method for making


A wireless raceway (100) employs bus bars (121), instead of cabling or other types of wires. The raceway (100) includes a pair of junction blocks (102). A bus bar assembly (116) holds the individual bus bars (121). The raceway (100) also includes a pair of modified Hterminals (122) having a central bus bar terminal (124) connected to each of a pair of receptacle terminals (126). The modified H-terminals (122) connect the individual bus bars (121) to external electrical assemblies through the junction blocks (102) without the need of wires or cables.

1. Field of the Invention
The present invention relates to electrical power systems and, more particularly, to arrangements for providing both a wireless raceway, and a wireless raceway which is adjustable in length.
2. Background Art
The use of computers, associated computer peripherals (e.g. printers and the like), copiers, facsimile machines, sophisticated telecommunications equipment and other electronic devices is continuing to rapidly increase in commercial, industrial and office environments. As a result, the importance of efficiently supplying power throughout these environments is also increasing. For example, the use of modular office systems, with multiple workstations and interior walls, has led to electrical systems relatively more sophisticated than conventional designs comprising receptacle mounts and electrical receptacles in stationary walls, with the receptacles energized from incoming power supplies extending through wall interiors. Such conventional and stationary wall-mounted systems were often located a substantial distance from the electrical devices to be energized and numerous electrical cords connecting the devices to the outlets would cause unsightly and sometimes dangerous entanglements. Thereafter, movable pluggable units having a number of receptacles on a common power source cord to be plugged into the conventional utility outlets were used. Again, however, such units resulted in unsightly and entangled arrays of electrical device cords.
With the growth of the use of electrical power in office systems, it became known to employ removable wall panels or the like, which defined modular workplace areas. Further, raceway areas were developed for use in the panels or other structures, for accommodating electrical wiring and electrical junction blocks near the locations to be energized. Typically, junction blocks were mounted within the raceway areas by attaching them with various types of structural arrangements. Outlet receptacle blocks having a number of receptacles were first formed as an integral part of the junction blocks. Thereafter, it became known to employ receptacles which were assembled as devices separate from the junction blocks, but were mechanically and electrically connectable to the junction blocks. During the past two decades, a substantial amount of research and development have been directed to raceways, junction blocks and receptacles, means for interconnection of the junction blocks and receptacles, and mounting of the junction blocks within the raceways.
Various arrangements have been utilized in the recent past in an attempt to provide electrical power. For example, McCarthy, U.S. Pat. No. 4,775,328, issued Oct. 4, 1988, discloses an electrical power assembly for installation in a raceway of a wall panel, of a type commonly used in modular wall systems for constructing office and other work areas. The McCarthy configuration includes a power block having seven wires, representing three separate circuits, and several ports for receiving different outlet receptacle adapters or modules. Different modules are utilized to connect a power cord or the like to the different circuits of the power block. Each of the ports of the power block has seven terminals, corresponding to the seven wires, and each of several outlet receptacle modules has a uniquely positioned set of three terminals for engaging a predetermined set of three of the seven power block terminals. In this manner, different outlet receptacle modules provide electrical connections to different ones of the three separate circuits. A disadvantage of this prior art arrangement is that a separate supply of receptacle modules must be kept, and a receptacle module of proper type must be found each time a change is to be made to a different circuit arrangement. This presents a substantial inconvenience to the user and requires a separate stocking of these parts.
Byrne, U.S. Pat. No. 5,087,207, issued Feb. 11, 1992, presented a substantial advance with respect to circuit selection. The Byrne arrangement utilized a pair of adapter blocks, each arrangeable in two physical orientations. These blocks provided an interface between an electrical outlet receptacle block and four different electrical circuits of a power distribution block. Each of the adapter blocks included terminals on one end for engaging the receptacle block, including one terminal disposed on the centerline of the adapter and a pair of terminals disposed on opposing sides and equidistant from the centerline. Further, each adapter block included terminals on an opposite end for engagement with the power distribution block. The adapter block also included terminals disposed on opposite sides of the centerline and offset from the centerline by different distances. Each adapter block could be changed from one physical orientation to another by rotation about the centerline. One of the blocks, in a first physical orientation, connected a first positive terminal, a first neutral terminal and a ground terminal of the power distribution block to the outlet receptacle block. In a second orientation, connection was made to a second one of the positive terminals, a second one of the neutral terminals and a ground terminal of the power distribution block to the outlet receptacle block. Correspondingly, the second adapter block, in a first physical orientation, connected a third positive terminal, a third neutral terminal and a ground terminal of the power distribution block to the outlet receptacle block. In a second physical orientation, the second adapter block connected a fourth positive terminal, a fourth neutral terminal and a ground terminal of the power distribution block to the outlet receptacle block.
Wilson et al, U.S. Pat. No. 4,367,370, issued Jan. 4, 1983, discloses an outlet receptacle block having a ground terminal, a common terminal and three positive terminals for engaging corresponding terminals of a junction block. The ground and common terminals are connected to the ground and common receptacle output terminals for engagement with the prongs of a standard three-prong electrical cord. The receptacle block further includes a switch which selectively connects one of the three positive prongs to the positive receptacle outlet connector, internal to the outlet receptacle block.
In another prior art arrangement in Tillmann, U.S. Pat. No. 4,666,223, issued May 19, 1987, an outlet receptacle block is provided with a movable terminal to selectively engage one of three positive junction block terminals. The outlet receptacle block of this prior art arrangement includes a conducting shaft electrically connected to the positive outlet terminal of the outlet receptacle block and to the movable terminal. The movable terminal may be slid upwardly or downwardly to a desired position for engagement with one of three positive connector terminals of the junction block.
In yet another prior art arrangement in Wilson et al, U.S. Pat. No. 4,781,609, issued Nov. 1, 1998, an outlet receptacle block is provided with a pair of slideable terminals mounted on a carrier so as to provide for synchronous movement of two contacts. A junction block is provided with a ground terminal, three positive terminals and three common terminals, thereby defining three separate circuits with a common ground. The carrier on the outlet receptacle block may be positioned so that one of its terminals engages one of the positive terminals of the junction block, while the other engages the corresponding common terminal. A sliding electrical contact internal to the receptacle block provides contact between the moveable terminals and corresponding terminals for engagement with the prongs of a standard electrical cord.
With several of the above-mentioned prior art arrangements, an electrical switch contact between a moveable part and a stationary part is employed to connect the outlet terminals of the outlet receptacle block.
Byrne, U.S. Pat. No. 5,096,431, issued Mar. 17, 1992, provided another substantial advance with an outlet receptacle block having rearrangeable terminals. In Byrne, an electrical outlet receptacle block comprises a housing and at least one flexible bus bar having one portion fixedly attached to the housing and electrically connected to one of the outlet receptacle terminals of the receptacle block. An end of the flexible bus bar is a moveable terminal end, which may be moved to at least two separate positions for selective alignment with different terminals of a junction block having at least two different circuits.
Byrne discloses one embodiment with an electrical junction block comprising eight terminals, with four positive terminals, two neutral terminals and two ground terminals. The outlet receptacle block is provided with three bus bars for connection to positive, neutral, and ground outlet terminals. The flexible bus bars may be selectively positioned to connect the ground outlet terminal to either of the two ground junction block terminals. In addition, the neutral outlet terminal can be connected to either of the two neutral junction block terminals, and the positive outlet terminal can be connect to any one of the four positive junction block terminals.
The outlet receptacle block can be provided with at least one manually operable control lever engaging the moveable end of at least one flexible bus bar. The housing of the receptacle outlet block is provided with an elongated slot on one surface for accommodating the control lever. The control lever can be disposed partially below the surface, with a protuberance extending through the slot. The protuberance is of a generally rectangular shape and fits snugly in the opening to prevent any significant rotation. The control lever, of which the protuberance is a part, is provided with an opening which engages a longitudinal section of a conductor bar. Movement of the control lever in the slot causes a bending in a portion of the control bar between the control lever and a fixed anchor point of the flexible bus bar internal to the receptacle outlet block housing. A terminal end portion of the bus bar extends beyond the control lever substantially perpendicular to an end wall of the receptacle block housing. This is provided for engagement with terminals of the junction block.
Stas, U.S. Pat. No. 2,996,566 discloses a floor-type outlet box for use within concrete flooring. The outlet box includes a duplex receptacle positioned so that the receptacle outlets extend vertically upward slightly beneath the floor level. A cover plate is hingedly mounted to the box and capable of being sealed to provide a water-tight housing flush with the concrete floor. Another, still earlier, disclosure of a junction box having electrical outlets for use in concrete floors is set forth in Buchanan, U.S. Pat. No. 1,928,198. The Buchanan patent is primarily directed to an arrangement for adjusting the position of the outlet box after the concrete floor is poured so as to compensate for any undesired displacement.
Several of the known arrangements for providing electrical receptacles in floors include arrangements for selectively positioning the receptacles between exposed and concealed positions. For example, Press, U.S. Pat. No. 3,622,684 discloses a floor receptacle mounting unit having electrical receptacles which can be rotated to a position in which the receptacles are exposed above the level of the floor or, alternatively, rotated to positions in which the receptacles are concealed below the floor level. Myers, U.S. Pat. No. 3,433,886 discloses an electrical junction box to be mounted flush with a floor. The junction box adjustably mounts an electrical service or receptacle box which is recessable below the floor surface through the use of adjusting machine screws. Other floor mounted electrical junction boxes and receptacles are shown in the following references: Kelly, U.S. Pat. No. 3,395,243; Wiesmann, U.S. Pat. No. 2,738,892; Fuller, U.S. Pat. No. 3,975,074; Guerrero, U.S. Pat. No. 2,811,574; MacLeod, Jr., U.S. Pat. No. 3,131,512; and Dubreulio, U.S. Pat. No. 3,794,956.
With respect to the previously cited references, most of these references are directed to floor mounted electrical receptacles and junction boxes to be mounted in permanent flooring. However, with the increase in use of modular offices, and for various other design and structural reasons, the use of access flooring is becoming more widespread. Such access flooring also allows the positioning of junction boxes and incoming power and signal cables to be placed beneath the floor after or during the design of the office systems (modular or otherwise) to be employed within the commercial or industrial environment. Such access flooring also allows for power and signal cables to be placed beneath the floor in a position which will not necessarily interfere with the placement of walls or, for that matter, furniture placement following complete office design. In addition, the use of such access flooring allows for junction boxes, electrical outlet boxes, power and signal cables to be selectively moved as the office systems are rearranged.
In known systems for utilizing electrical power with access flooring, power and signal cables are interconnected between incoming power supplies and junction or electrical receptacle boxes referred to herein as access floor modules. Appropriate office equipment is directly connected to receptacle outlets within the access modules which are designed specifically for receiving the receptacle outlets.
An example of a known access floor module is disclosed in Brownlie et al., U.S. Pat. No. 5,122,069. With reference to the drawings and the numerals disclosed in the Brownlie et al. patent, FIGS. 1-4 illustrate an access flooring module to be mounted in an opening 4 provided in an access floor. The module 2 is movable between an open position (FIG. 3) and a closed position (FIG. 4). Recesses 24 are provided so as to receive electrical components such as power sockets 34 or signal sockets 36 shown in FIG. 1. Metal plates 25 (shown in FIG. 2) selectively provide electrical contact with electrical components to be utilized with the module 2. In an alternative embodiment of the Brownlie et al. patent, FIG. 12 depicts interconnection of high tension cables 240 and low tension cables 241 to the rear of an alternative module 200. The high tension cable 240 is secured through a hard wire bracket 209, with the low tension cable 241 secured through a data bracket 211. Cable ties 242 are utilized to secure the cables to the rear of the module.
Although the prior art shows a number of designs for floor-mounted boxes capable of mounting electrical receptacles, an important aspect of floor-mounted arrangements is the overall "system." The overall system includes all of the junction boxes, electrical receptacle boxes and outlets, and the requisite cabling, including the means for interconnection of cabling. For example, if the system requires cables of different types with respect to lengths, connectors, and other structural considerations, the system designer's job is more complex, since the designer must essentially have a final system design before ordering the requisite cabling. Although an inventory of various cables may be ordered and stored, such an inventory may be expensive, take up valuable storage space and involve components which are never used. Still further, if a voluminous inventory is not desired, the designer must have exact details as to positioning of electrical outlets, system dimensions and other layout information before undertaking the process of ordering the cabling.
Other design and assembly issues for these types of electrical systems relate to system components other than cabling. For example, such systems may utilize one type of component for a junction box, and another type of component for mounting electrical receptacles. Again, such a structure suffers from the same problems previously described with respect to requiring various types of cables for the overall system.
In addition to issues associated with cabling, junction boxes and receptacle mounting structures, the means for interconnecting system components is also important. For example, if the interconnection of cables to other cables, or to junction boxes and the like, requires hard-wired connections, problems arise with respect to both design and assembly.


An interface may be selected. First, it may be determined that an application is intended to use a first one of a plurality of network interfaces. Next, a first one of a plurality of routing tables may be selected corresponding to the determined first one of the plurality of network interfaces. Then the selected first one of the plurality of routing tables may be used to communicate with a first device on a first network over the determined first one of the plurality of network interfaces.

Dynamic host configuration protocol (DHCP) is an automatic configuration protocol used on internet protocol (IP) networks. Computers that are connected to IP networks must be configured before they can communicate with other computers on the network. DHCP allows a computer to be configured automatically, eliminating the need for intervention by a network administrator. It also provides a central database for keeping track of computers that have been connected to the network. This prevents two computers from accidentally being configured with the same IP address. In the absence of DHCP, hosts may be manually configured with an IP address.

Method to select interface for IP packets when destination subnet is reachable on multiple interfaces


A device is described that can be used by surgeons to provide quick and accurate face-lifting maneuvers that minimize the amount of tissue that has to be removed. The device comprises of a hollow undermining shaft with specially designed tip that can safely separate tissue planes and lyse fibrous tissue. Laser light can be delivered down the shaft to heat and cause tissue contraction. Device can also include a temperature sensor that can be used to control laser power. Optionally the device can also use ultrasound or electrosurgical energy to improve tissue lysing.

1. Field of the Invention
This invention relates to a surgical device for performing face-lifting using electromagnetic radiation, and more particularly to a device with a specialized tip design that delivers laser light and optionally ultrasonic energy. The invention provides a surgical device that can improve the accuracy and speed of face-lift operations. Use of the present invention may controllably cause thermally related healing contraction of the target tissues thus allowing face lifting in younger patients without the removal or cutting-out of skin in properly selected patients.
2. Description of Related Art
Critical Anatomy and Nomenclature:
Definitions:
Cutting (in surgery) will be defined as relatively cleanly breaking through similar or dissimilar tissues with minimal adjacent tissue trauma and thus little tissue stretching, tearing or ripping. Lysis (in surgery) will be defined as breaking through similar or dissimilar tissues with or without adjacent tissue trauma and may involve stretching, tearing or ripping. Depending upon the tissues lysed, the degree of stretching or tearing of lysed tissue edges may be inconsequential or may even result in a desirable benefit such as post surgical contraction. Planes of tissue are not often flat and represent the curviform intersection of dissimilar tissues and are made at least partly of fibrous tissues, either loose and spongy or firm and tough. Planes between the soft internal organs are usually loose and spongy. Planes of tissues in the face and on bones are firm and tough. Undermining will be defined as tissue separation either within or between defined tissue planes. Undermining may be sharp (instrument) or dull (instrument) depending upon the amount of fibrous tissue binding or existing between the tissue planes to be separated. Undermining is usually performed, as is most surgery, with the intention of minimizing trauma. Sharp instrument undermining is usually performed to separate highly fibrous or collagenous tissues, however sharp undermining suffers from the risk of penetrating adjacent tissues inadvertently because of loss of ability to follow the desired plane. Inability to follow or maintain the plane in sharp undermining is frequently due to limited visibility, difficulty xe2x80x9cfeelingxe2x80x9d the fibrous plane, or scarring (collagen fibrosis) resulting from previous trauma or surgery. Even experienced surgeons may from time to time lose the correct plane of sharp undermining; great skill is required. Blunt undermining allows a rounded, non-sharp tipped, instrument or even human finger to find the path of least resistance between tissues; once the desired plane is found by the surgeon, it is easy to maintain the plane of blunt undermining until the task is complete. Unfortunately, blunt undermining between highly fibrous tissues such as the human face usually causes tunneling with thick fibrous walls. Dissection usually implies sorting out and identification of tissues and usually implies that some sort of undermining has been performed to isolate the desired structure(s). In face-lifting surgery, plastic surgeons have so commonly used the terms undermining and dissection interchangeably that they have become synonymous in this specific situation. Tracking means to maintain a direction of movement upon forcing a tissue separating instrument without unpredictable movement or leaving the desired tissue plane(s). Planar tracking means to stay in the same tissue planes. Linear tracking means to move uniformly in a straight or uniformly curved path without unpredictable movement. Groups of linear tracks may form a network that creates an undermined tissue plane.
Anatomical Perspective: Lysis or undermining in one dimension (linear=x) implies forming a tunnel. Lysing or undermining in 2 dimensions at any one instant forms a plane (x,y). Traditional face-lift undermining is done just under the leather (dermis) layer of the skin where dermis joins underlying fat (or subcutaneous, xe2x80x9cSQxe2x80x9d). Even deeper within the SQ fat run larger blood vessels and delicate, non-regenerating motor nerves to the muscles that give the human face motion and expression. Deep/beneath to the SQ fat reside the muscles and glands of the face. The relevant face-lift anatomy may be referenced in {Micheli-Pellegrini V. Surgical Anatomy and Dynamics in Face Lifts. Facial Plastic Surgery. 1992:8:1-10. and Gosain AK et al. Surgical Anatomy of the SMAS: a reinvestigation. Plast Reconstr Surg. 1993: 92:1254-1263. and Jost G, Lamouche G. SMAS in rhytidectomy. Aesthetic Plast Surg 6:69, 1982.} The SQ fat differs from body location to body location. On the face, the SQ fat has many fiber-bundles (septae) carrying nerves and blood vessels. If a surgeon were to move, shove, or forwardly-push a blunt, dull-tipped, 1-inch chisel or pencil shaped device through the fat of the face where SQ abuts the dermis, the sheer thickness of the fiber bundles would likely cause slippage of the device and result in the formation of pockets or tunnels surrounded by compacted fiber bundles or septae. Proper performance of a face-lift involves breaking the septae at a proper level to avoid damaging more important structures such as blood vessels and nerves and glands.
Disadvantages of the current techniques are numerous. Face-lifting devices described in the prior art resemble undermining devices that were constructed with cutting edges that rely entirely on the skill of the surgeon to maintain control. Inadvertent lateral cutting or tissue trauma may be difficult to control. In addition, speed of separation is effected to ensure accuracy by the surgeon in separating fibrous tissue planes. There are two principle locations for face lift undermining (dissection): in the more common lower facelift (cheek/neck-lift) undermining in the subcutaneous tissues is customarily performed; in the less common upper facelift (which approximates brow-lifting) undermining in the subgaleal or temporalis fascia plane is customarily performed. Use of prior art undermining devices (including scissors, sharp rhytisectors, etc) in these planes during cosmetic surgery has, at times, resulted in unwanted cutting, trauma or perforation of adjacent structures. Scissors and rhytisectors are planar cutting instruments; thus, the position of the cutting edges with respect to the surface of the face is controllable only by the surgeon estimating location as no 3rd dimensional bulbous limitation exists. Unfortunately, scissors with 3 dimensionally xe2x80x9cbulbousxe2x80x9d, rounded tips can not close all the way to cut target tissue. Scissors with 2 dimensionally rounded tips can close all the way to cut target tissue but may wander inadvertently between tissue planes due to the thin third dimension (thickness) of the scissors blades.
Rubin (U.S. Pat. No. 3,667,470) describe a bone shaver and grooving device which consists of a single sharp edged extension protruding perpendicular to the plane of motion of the cutting edge of the device. The extension is intended to carve and maintain a groove in rigid, immobile, bone as it is driven forward by a surgeon""s hammer. This device is impractical for lysing facial planes because the extension would severely damage blood vessels and delicate nerves. In addition, Rubinxe2x80x9d invetion would not maintain a planar track in soft tissues. Hendel (U.S. Pat. No. 4,600,005) describes a guided osteotome for harvesting cranial bone graft that has a single cutting tip between two bulb like guides at the edges. The guides prevent the hammer driven cutting edge from penetrating the skull too deeply as the harvesting cutting edge would tend to xe2x80x9cdivexe2x80x9d deep into the skull toward brain tissue if unhindered (vertical tracking control). However, these single guides with their geometry can not effectively compress or pass through the collagenous, fibrous tissues into recessions making for a more precise lysis of the grouped fibers and bundles.
Current face-lifting instruments that cut with other than manual energy do not address the novel concept of a xe2x80x9cprotected planexe2x80x9d during energized face-lifting dissection. Current lasers must be fired from positions outside the patient to energize tissue within the face to cut in a very imprecise fashion (reference: in Manual of Tumescent Liposculpture and Laser Cosmetic Surgery by Cook R C and Cook K K, Lippincott, Williams, and Wilkins, Philadelphia ISBN: 0-7817-1987-9, 1999). Tissue is damaged with little control. Current electrosurgical devices for face-lift tissue energizing must be delivered through large open pockets or through the limited access and slow moving, tedious endoscopes. Farin (U.S. Pat. No. 5,776,092) describes a single tube device that can deliver laser, ultrasound or radio frequency devices to treat tissue. However, Farin""s device is not intended for separating tissue planes and is suceptible to catching, tearing or puncturing the tissue when manipulated. It would be advantageous to provide a safe harbor for the precise application of energy to proper face-lift tissues to be separated and energized while excluding vital structures such as nerves and delicate vessels and maintaining an exact distance from the very delicate surface of the skin. It would be additionally advantageous for the same provisions to allow for a uniform forward tracking and feel of motion of the device that provides a surgeon with instantaneous knowledge. Properly sized and placed protrusions and recessions address all of these problems in a manner not previously possible.
One of the most recent competing procedures to incompletely dissect/lyse/cut a face-lift plane is traditional or ultrasonic liposuction. Unfortunately, dissection is incomplete as the cannulas only make tunnels. The tissues between the tunnels must be cut with scissors in order to create a plane. When the scissors cuts the fiber tissues and blood vessels constituting the walls of the tunnels, bleeding and trauma occur and frequently require spot coagulation under visualization. Other severe drawbacks of the incomplete undermining that liposuction cannulas perform is the common trauma and resultant mouth droop paralysis that occurs in the hands of even prominent surgeons when the delicate and anatomically unpredictable (20% of the population) marginal mandibular nerve is cut. Additionally, ultrasonic cannulas become hot and can cause thermal bums called xe2x80x9cend hitsxe2x80x9d when the cannula tip is thrust against the inside of the skin as is common during the procedure.
Just as sharp undermining or dissection has its disadvantages, as previously mentioned, blunt dissection suffers from its own difficulties as well. Forcing a blunt object through tissue avoids indiscriminate sharp cutting of important structures (nerves, vessels). Blunt undermining compacts the stronger, firmer, strands of collagen even contained within tissues as soft fat into thicker xe2x80x9cbandsxe2x80x9d (some overly thick for uniform cutting). Undesirably for a face-lift, traditional blunt object undermining may indiscreminantely force aside and compact septae causing incomplete lysis or freeing of the tissues. Also unfortunately for face-lifting, traditional purely blunt object undermining will result in random motion or uncontrollable-slippage of the underminer tip on forward motion and thusly loss of precise tracking of the underminer through target tissue.
Currently it takes surgeons between 20 minutes and one hour to dissect/undermine/lyse/lift a lower face. It usually takes between 10 minutes and 30 minutes, depending upon the patient to spot coagulate/seal all of the blood vessels that were cut during the aforementioned lysing portion of the face-lift. For upper face-lifting times are less than half that mentioned for lower face-lifting. The present invention would reduce time for a surgeon to do both the duties of lysing and coagulation since the device performs both tasks as well as aids in maintaining proper positioning and tracking. The time reduction should be at least 50-75%. Reduced operating time means less time a wound is open to potential infection, lowered surgical costs and less time and therefore less risk under anesthesia and thus a general improvement in the procedure.
There exists a special subset of the general population that may benefit uniquely from the present invention. Men and women between the ages of 45 and 55 are just beginning to droop and develop folds. However, there is not much undulating wrinkling as in older patients. Currently long incisions of 10-20 cm are made around each of the two ears, for the purposes of hiding the scars. Skin is cut out and discarded and the remaining skin stretched. Skin does not thicken in response to stretching; it only thins. Unfortunately, some plastic surgeons in the early 1990""s advocated xe2x80x9cprophylacticxe2x80x9d or xe2x80x9cpreemptivexe2x80x9d face-lifting on women in their 40""s purportedly to xe2x80x9cstay ahead of nature.xe2x80x9d This philosophy has now been discounted and discredited by the vast majority of reputable experts. With the present invention, tightening will be most dramatic in younger patients between 45 and 55 years of age such that surgeons may not have to cut-out or stretch skin for a desirable effect for most patients in this population. In this case, the present invention is inserted through only 3 relatively small incisions of less than 1 cm each and energy is applied to the upper subcutaneous, lower dermal and platysmal face-lift layers. If the 3 small incisions can be used and no skin excised then the procedure will take less than 15 minutes following anesthesia and the effects will last for at least several years.
Given the disadvantages and deficiencies of current face-lifting techniques a need exists for a device that provides a fast and safe alternative. The present invention combines a unique lysing design with laser irradiation to efficiently lyse and simultaneously induce the thermal contraction necessary for face-lifting. The present invention provides a process for human face-lifting, which can be used in hospitals as well as office-based surgery and minimizes pain and risk of injury.
It is, therefore, an object of the present invention to provide an undermining device that can position lysing surfaces at a proper level for fibrous tissue lysing during a face-lift. It is a further object of the invention to provide quick and accurate face-lifting maneuvers. It is yet a further object of the invention to provide a surgical face-lifting device that easily maintains the proper dissection plane. Additionally, it has been shown that thermal effects to the collagenous (dermal, superficial platysma musculature and other) tissues of the face in the facelift plane can cause cosmetically desirable contraction of the dermal tissues with beneficial tightening of the facial tissues.
The object of the present invention is to provide a method and a device that can be used by surgeons to provide quick and accurate face-lifting maneuvers that minimize the amount of tissue that has to be removed. The device is comprised of a hollow undermining shaft with a special tip that can be easily positioned between dissection planes in tissue and then manipulated to separate tissue planes and lyse fibrous tissue. A laser light source and delivering means which delivers energy to the distal end of the shaft, a temperature sensor that monitors the tissue temperature, and control electronics that process temperature information to control the laser power for optimum tissue contraction. An optional secondary light source that is visible to the surgeon can be used to help visualize the location of the laser exit window. Optionally the device can also use ultrasound energy delivered down the shaft to improve tissue lysing.
It is a further object of the invention to provide a surgical face-lifting device that easily maintains the proper dissection plane while lysing and delivers laser energy to the internal collagenous tissues of the face to induce skin tightening.
In the preferred embodiment of the invention, the user sets the desired tissue temperature on an external control unit using a touch pad or other user interface. The shaft of the device is then inserted through a small (xcx9c1 cm long) incision and positioned at the desired tissue plane. For lower face-lifting the surgeon incises the skin in front of the ears and under the chin. Force is then applied to the shaft of the device by the users hand to separate tissue planes while excluding critical structures (nerves, vessels) thus avoiding entanglement or trauma or indiscriminate cutting of these important structures. The same protrusions that exclude critical structures by virtue of their relationship to the cutting recessed segments also serve to position the depth of the present invention with respect to the lower dermis. The spacing of the protrusions (bulbs) and recessions (lysing segments) maintains the tracking of the instrument. Tracking is instantly palpable by the surgeon and requires no monitor to know how the device is moving. Both the number and spacing of protrusions in the present invention reduce wobble or lateral (horizontal) slippage during forward thrusting of the shaft. Uniquely vertical slippage is prohibited as well. The width of the protrusions/bulbs maintains the correct distance between the lysing segments and the delicate underside of the superficial skin or dermis. The tip of the device and the action of the device can be felt/appreciated without direct visualization (endoscope). The surgeon can palpably feel the device is tracking in the proper location. The feel of the device as it moves with palpable and easily grade-able resistance through the facial tissues can immediately tell the user the location and the amount of undermining that has occurred at that location.
The unique tip is comprised of alternating, but relatively symmetrical-across-a-midline, protrusions and recessions. The protrusions can be bulbous, geometric, etc. as long as the tips of the protrusions are able to push and compress tissues into the cutting recessed segments. The recessed segments have a sharpened edge which effectively lyses the tissue that comes into contact as the device is pushed forward. The close spacing of the grooves (caused by the alternation of tip protrusions and recessions) provides the user with a feel during forced tissue movement and significantly limits slippage. Again, the tip of the device, and the action of the device can be felt/appreciated without direct visualization (endoscope).
If desired by the user, laser light is transmitted from the laser to the hand piece and down the shaft and exits an optical window near the distal end of the shaft to heat the tissue which lies near the window. The laser light propagates away from the face to effectively heat the skin layer from the inside out. By selecting an appropriate laser wavelength, the laser penetration depth can be adjusted to control the thickness of heated tissue. For skin tightening, a CO2 laser with a wavelength of 10 xcexcm will deliver good results, other possible lasers include Er:Yag, Ho:Yag, and Nd:Yag. The purpose of the laser energy is to alter/irritate the collagen so as to controllably cause later shrinkage and to optionally to control any bleeding. Since most preferred laser sources are invisible to the human eye the device will offer the user the option to simultaneously transmit visible light down the shaft to give the user the ability to visualize the region being treated. For example, red light that is easily transmitted through several millimeters of skin, could be safely used to guide the surgeon. Laser irradiation can be controlled manually by the user or alternatively automatically controlled to prevent excessive or inappropriate thermal damage.
In the preferred embodiment the temperature of the target tissue is measured with a non-contact temperature sensor and the value displayed and used by the laser control unit to actively control the laser power. The preferred temperature sensor would be an infrared temperature sensor, but other conventional sensors may be used, such as fiber optic fluorescence temperature sensors, and thermocouple sensors.
In order to improve lysing efficiency, one embodiment of the device incorporates an ultrasound transducer into the hand piece that transmits ultrasound energy down the shaft. A lower frequency vibrating transducer could also be incorporated into the device to improve lysing.
For example, the shaft may be vibrated at frequencies lower than 5000 Hz.
In another embodiment, the recessed cutting segments of the device are driven by an electrosurgical RF generator to improve Iysing and allow RF heating of tissue.
The present invention can be used to improve the efficacy and safety of face-lifting and is thus useful in a variety of cosmetic procedures. The forgoing and other objects, features, and advantages of the present invention will become apparent from the following description and accompanying drawings.
The disclosures of this publication and the disclosures of all other publications recited herein are incorporated by reference as if fully set forth herein.

Surgical device for performing face-lifting using electromagnetic radiation