Stock material or miscellaneous articles – All metal or with adjacent metals – Laterally noncoextensive components
Reexamination Certificate
1999-02-26
2002-11-05
Beck, Shrive P. (Department: 1762)
Stock material or miscellaneous articles
All metal or with adjacent metals
Laterally noncoextensive components
C428S621000, C428S626000, C428S655000, C428S670000, C623S014130
Reexamination Certificate
active
06475639
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a novel method of manufacturing actuators, sensors and novel applications of the actuators and sensors manufactured according to the novel method.
2. Background Art
The creation of sensors and controllable actuators, or synthetic muscles, is known. Sensors and artificial muscles or actuators made from ion-exchange membranes are relatively new but also known.
U.S. Pat. No. 4,364,803, to Nidola et al., discloses a process for deposition of catalytic electrodes on ion-exchange membranes and an electrolytic cell made by the process. The process involves contacting a water-swollen, roughened membrane with an amphoteric organic or metal salt thereof, such as alkali metal salts thereof, e.g., platinum, palladium, and nickel. After further processing, the membrane is then contacted with a solution of the selected metal salt wherein sorption of the metal salts takes place mainly on the membrane surface in the vicinity of the polar groups of the polymer or the pre-adsorbed polar groups of the amphoteric organic. The absorbed/adsorbed metal creates the catalytic electrodes. The patent discloses operation of the electrode in the presence of sodium brine/caustic soda.
U.S. Pat. No. 4,522,698, to Maget, discloses a prime mover that uses pressure increases and decreases induced by converting molecules of electrochemically active material to ions, transporting ions through an electrolytic membrane and reconverting the ions to molecules. The prime mover includes gas-tight compartments filled with an electrochemically active material and separated by an electrolytic membrane, such as an ion-exchange membrane, that incorporates electrodes so that a voltage gradient can be established across the membrane to induce current flow through the membrane. When the current flows through the membrane, molecules travel through the membrane and are reconverted to molecules in the opposite compartment causing a pressure increase in the receiving compartment and a pressure decrease in the other compartment. The pressure changes are converted to mechanical motion that can be used as a driver for a mechanical load. The disadvantages of this technique are that the resulting motion is small and the pressure increase may rupture the membrane.
U.S. Pat. No. 4,748,737, to Charles et al., discloses a method of removing surface oxidation from particulates. The method includes removing oxide film from particulates with a liquid reducing agent or strong acid comprising an alkali metal., or a hydroxide of an alkali metal, wherein alkali metals such as sodium, lithium, potassium, or mixtures thereof are used.
U.S. Pat. No. 5,100,933, to Tanaka, et al., discloses the use of ionized cross-linked polyacrylamide gels as engines or artificial muscles; the gels can contain a metal ion and are capable of discontinuous volume changes induced by infinitesimal changes in environment. The gel is made by dissolving acrylamide monomers and bisacrylamide monomers in water, adding a polymerization initiator (in particular, ammonium persulfate and TEMED, or tetramethyl-ethylene-diamine) to the solution, soaking the gel sample in water to wash away all residual monomers and initiators, immersing the gel in a basic solution of TEMED for up to 60 days, then immersing the gel in a solvent (in particular, acetone, acetone in water, ethanol and water, or methanol and water). The primary disadvantages of these actuators are generally that the response time of the gel is much longer than that of other known actuator components and that the gel must be contained in the solvent bath. The gels are also mechanically brittle and easily broken.
U.S. Pat. No. 5,250,167, to Adolf, et al., discloses actuators or synthetic muscles, using polymeric gels contained in compliant containers with their solvents; these actuators undergo substantial expansion and contraction when subjected to changing environments. The actuators may be rigid or flexible and may be computer-controlled. The driver may also be electrolytic, where application of a voltage across the polymer gel causes a pH gradient to evolve between the electrodes. For example, filling the polymer fibers with platinum by alternatively treating them with solutions of platinic chloride and sodium borohydride obtains a reversible expansion and contraction of the fiber with the application of an electric field. The actuating gel itself is the only moving part required and the electric field may be only on the order of a few volts per centimeter. The disadvantage is that actuator performance is dictated by the parameters of the polymeric gel used. Furthermore, liquid containment is required to make the actuators stronger and not so easily broken.
U.S. Pat. No. 5,268,082, to Oguro et al., discloses an actuator element based on a membrane electrode that when subject to a DC voltage of 0.1 Volts to 2.0 Volts undergoes a displacement proportional to the square of its length (Col. 3; II. 4, 5). This description of the displacement in relation to membrane electrode length is patently erroneous. For example, for a length of unity, the displacement would be also unity. Consider further, for a length less than unity, the displacement would be greater than the length whereas for a length of 100, displacement would be less than the length, i.e., 10% of the length. Therefore, the specification relating to displacement is in error. Even if the specification were to have meant square “root,” ambiguity and vagueness would remain. Further ambiguities exist in the specification of this patent. For instance, in Example 4 (Col. 5; I. 27), a clamped membrane having a length of 5 mm extending beyond the clamp was placed in a salt water solution and exposed to a rectangular wave on the order of 0.1 Hz. For this example, a tip displacement of 10 mm was measured. This is a physical impossibility. In Example 5, an actuator element as used in Example 4 produced a displacement of +/−0.36 mm (Col. 6; II. 18-20). The specification states that this displacement was about 1.8 times that of Example 4 (Col 6; II. 18-22), or approximately 18 mm. All of the foregoing descriptions related to membrane tip displacement are obviously in error. However, in another example, Example 3, a membrane 3 mm in length was placed in a 4% salt-water solution and exposed to 1.6 Volts resulting in a tip displacement of 0.3 mm, 10% of length. Therefore, one of ordinary skill in the art would conclude that the specification does not enable nor support tip displacements greater than 10% of the membrane length.
U.S. Pat. No. 5,389,222, to Shahinpoor, discloses electrically controllable polymeric gel actuators or synthetic muscles, using gels made of polyvinyl alcohol, polyacrylic acid, polyacrylonitrile, or polyacrylamide contained in an electrolytic solvent bath. These actuators operate by reacting to changes in the ionization of a surrounding electrolyte by expanding or contracting, and can be spring-loaded and/or mechanically biased for specific applications. Polymeric gel configurations such as sheets, solid shapes or fiber aggregates are contemplated, as are the use of a salt water solution for the electrolyte, and a platinum catalyst in the actuator housing to recombine the hydrogen and oxygen produced as a result of electrolysis during ionization of the electrolyte. Again, liquid containment is required to maintain strength and electric controllability, and not enough deformation or displacement is generated.
U.S. Pat. No. 5,531,664, to Adachi et al., discloses a bending actuator having a coil sheath with a fixed distal end and a free proximal end. The distal end portion of the device is formed of an axially expanding and contracting shape memory alloy. The device produces adequate drive force to bend the bendable portions of medical probes incorporating the actuator. The ability to bend such probes facilitates in situ navigation.
“Development of a Novel Electrochemically Active Membrane and ‘Smart’ Material Based Vibration Sensor/Damper,” by Sadeghipour et
Mojarrad Mehran
Shahinpoor Mohsen
Armijo Dennis F.
Beck Shrive P.
Crockford Kirsten A.
Shahinpoor Mohsen
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