Patents by Inventor David C. May
David C. May has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 5835271Abstract: A retroreflective element that exhibits exceptional wet retroreflectivity, and a method of manufacturing the same. The retroreflective element includes an assembly having a multi-sided retroreflector and a clear thermoplastic. In one embodiment, the clear thermoplastic is at least partially thermally deformed to create a convex retroreflective dome for capturing high incident angle light rays. The retroreflective elements may be used in a pavement marking system, such as attached to pavement marking tape or deposited in pavement marking paint.Type: GrantFiled: June 29, 1995Date of Patent: November 10, 1998Assignee: Minnesota Mining and Manufacturing CompanyInventors: Larry K. Stump, Thomas V. Kusilek, David C. May, Terry R. Bailey, Louis C. Belisle
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Patent number: 5816305Abstract: A method of protecting an object during application of a fluid onto a surface. The method includes the following steps, (1) providing a cover having a first layer and a second layer attached together, the first layer including a non-woven fabric material and the second layer including a plastic material, and (2) positioning the cover relative to the object so that the fluid is prevented from contacting the object during application of the fluid onto the surface. A drop cloth having a first layer which includes a non-woven fabric material, and a second layer which includes a plastic material, is also disclosed.Type: GrantFiled: December 21, 1995Date of Patent: October 6, 1998Assignee: D.C. Macy CorporationInventor: David C. May
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Patent number: 5774265Abstract: All-ceramic retroreflective elements which may be used in pavement markings comprising an opacified ceramic core and ceramic optical elements partially embedded into the core.Type: GrantFiled: February 5, 1996Date of Patent: June 30, 1998Assignee: Minnesota Mining and Manufacturing CompanyInventors: James P. Mathers, Chris J. Goodbrake, Kathleen A. Hachey, Thomas P. Hedblom, Kathleen M. Humpal, Roger W. Lange, David C. May, Kyung H. Moh, Thomas E. Forester
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Patent number: 5677050Abstract: Retroreflective sheeting having an abrasion-resistant ceramer coating that is prepared from about 20% to about 80% ethylenically unsaturated monomers; about 10% to about 50% of acrylate functionalized colloidal silica; and about 5% to about 40% N,N-disubstituted acrylamide or N-substituted-N-vinyl-amide monomer having a molecular weight between 99 and 500 atomic mass units; wherein said percentages are weight percents of the total weight of said coating. A method of coating retroreflective sheeting with an abrasion-resistant cured ceramer layer is also disclosed.Type: GrantFiled: May 19, 1995Date of Patent: October 14, 1997Assignee: Minnesota Mining and Manufacturing CompanyInventors: Zayn Bilkadi, David C. May
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Patent number: 5667335Abstract: A fiber-reinforced raised pavement marker made of a composite material comprising an isotropic mixture of a polymeric material, reinforcing fibers and a filler material. The results of finite element analysis and composite technology have been combined to produce a pavement marker having high flexural strength and impact resistance without the need for an impact-resistant shell. Durable, high strength composite pavement markers are made by casting a homogenous mixture of chopped glass fibers and a filler material in a polymeric matrix. Placement of a retroreflective lens within the mold followed by pouring and curing the composite material results in a finished product upon release from the mold.Type: GrantFiled: May 19, 1995Date of Patent: September 16, 1997Assignee: Minnesota Mining and Manufacturing CommpanyInventors: Sithya S. Khieu, David C. May
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Patent number: 5571362Abstract: A retroreflective article and a method for making same are taught. The retroreflective article comprises transparent microspheres and both specular and diffuse reflective pigments dispersed in a binder layer. The utilization of both types of pigments results in improved retroreflectivity over a greater range of entrance angles than if only one or the other pigment alone were used.Type: GrantFiled: April 7, 1995Date of Patent: November 5, 1996Assignee: Minnesota Mining And Manufacturing CompanyInventors: Kathleen A. Hachey, Thomas P. Hedblom, David C. May
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Patent number: 5417515Abstract: A retroreflective article and a method for making same are taught. The retroreflective article comprises transparent microspheres and both specular and diffuse reflective pigments dispersed in a binder layer. The utilization of both types of pigments results in improved retroreflectivity over a greater range of entrance angles than if only one or the other pigment alone were used.Type: GrantFiled: May 20, 1994Date of Patent: May 23, 1995Assignee: Minnesota Mining and Manufacturing CompanyInventors: Kathleen A. Hachey, Thomas P. Hedblom, David C. May
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Patent number: 5391015Abstract: A pavement marker includes an object, such as a sheet or a raised pavement marker body, having an upper surface useful as a pavement marking indicium and a lower surface, and a bottom layer of polyorganosiloxane pressure-sensitive adhesive in intimate contact with the lower surface. A pressure-sensitive adhesive laminate system for attaching a pavement marker to a roadway surface includes a first layer of pressure-sensitive adhesive material,such as a polyorganosiloxane adhesive, a second layer of pressure-sensitive adhesive material, and a layer of deformable material interposed between the first and second pressure-sensitive adhesive layers, wherein the deformable material of the interposed layer is characterized by high cohesive (shear) strength. A method of marking a pavement having a temperature below 15.degree. C.Type: GrantFiled: September 10, 1993Date of Patent: February 21, 1995Assignee: Minnesota Mining and Manufacturing CompanyInventors: James M. Kaczmarczik, James E. Lasch, Gregory F. Jacobs, David C. May, Daniel J. Willie
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Patent number: 5310278Abstract: A pavement marker includes an object, such as a sheet or a raised pavement marker body, having an upper surface useful as a pavement marking indicium and a lower surface, and a bottom layer of polyorganosiloxane pressure-sensitive adhesive in intimate contact with the lower surface. A pressure-sensitive adhesive laminate system for attaching a pavement marker to a roadway surface includes a first layer of pressure-sensitive adhesive material, such as a polyorganosiloxane adhesive, a second layer of pressure-sensitive adhesive material, and a layer of deformable material interposed between the first and second pressure-sensitive adhesive layers, wherein the deformable material of the interposed layer is characterized by high cohesive (shear) strength. A method of marking a pavement having a temperature below 15.degree. C.Type: GrantFiled: November 18, 1992Date of Patent: May 10, 1994Assignee: Minnesota Mining and Manufacturing CompanyInventors: James M. Kaczmarczik, James E. Lasch, Gregory F. Jacobs, David C. May, Daniel J. Willie
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Patent number: 4875798Abstract: A raised retroreflective pavement marker that provides both improved retroreflectivity and longer life has a rigid opaque, synthetic resin body having at its front face septa to which a plastic cube-corner reflector has been bonded to provide a plurality of hermetically sealed cells beneath the reflector. This pavement marker differs from those on the market in that the thickness of its reflector is less than 2 mm, and it has preferably at least 500 cube-corner elements per cm.sup.2.Type: GrantFiled: June 30, 1988Date of Patent: October 24, 1989Assignee: Minnesota Mining and Manufacturing CompanyInventor: David C. May
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Patent number: 4719621Abstract: A digital system comprising a synchronous fastbus for interconnecting a cluster of devices such as processors and for interconnecting a plurality of said clusters. Information is transferred over the synchronous fastbus using a parallel digital word information packet. All required bus control signals including acknowledge and non-acknowledge signals take place within the same packet transfer fastbus cycle time. A command information packet is transferred over the fastbus separately from a response information packet thereby leaving the fastbus free until a response packet is returned to the requestor. During the interim other devices are allowed to access the fastbus, thereby increasing significantly fastbus utilization.Type: GrantFiled: July 15, 1985Date of Patent: January 12, 1988Assignee: Raytheon CompanyInventor: David C. May
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Patent number: 4648689Abstract: A lane delineation tape is disclosed comprising a strip of cellular polymer having a reflecting layer on top and an adhesive on the bottom surface for adhering it to a road surface. Preferably it is made of elastomeric foam having a relatively low compressive strength, e.g. 100 kPa at 25% compression.Type: GrantFiled: May 3, 1985Date of Patent: March 10, 1987Assignee: Minnesota Mining and Manufacturing CompanyInventor: David C. May
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Patent number: 4626127Abstract: Described is a raised pavement marker comprised of (referring to FIG. 1) a hollow, flexible, elastomeric body 2, a reflective film 4, and a pressure-sensitive adhesive 3. Raised portion 5 provides back support for the reflective film. The hollow body has a compressive strength of less than about 100 kiloPascals at 25 percent compression so that it yields readily to vehicle wheels traversing the marker, but it regains its approximate original shape after the wheels have passed over it.Type: GrantFiled: May 6, 1985Date of Patent: December 2, 1986Inventor: David C. May
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Patent number: 4534673Abstract: Described is a raised pavement marker comprised of (referring to FIG. 1): a flexible foam body 2, a reflective film 4, and a pressure-sensitive adhesive 3. Raised portion 5 provides back support for the reflective film. This pavement marker has significant advantages over existing markers in terms of cost and ease of placement on the road surface. A lane delineation tape is also disclosed.Type: GrantFiled: April 11, 1983Date of Patent: August 13, 1985Assignee: Minnesota Mining and Manufacturing CompanyInventor: David C. May
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Patent number: 4521129Abstract: Flexible, raised pavement markers having improved shapes which take advantage of relief cuts and ribs to increase the durability and retention of reflectivity. One embodiment of such a marker comprises: a flexible body made of sponge rubber and having a raised surface connected to a base portion through a connecting portion, a reflective film attached to the raised portion, and a pressure-sensitive adhesive on the base. Relief cuts along the back of the connecting portion provide a bending or folding action whereby the reflective film is made to lie flat when a tire passes over the marker, thus protecting the reflective sheeting from scuffing.Type: GrantFiled: June 17, 1983Date of Patent: June 4, 1985Assignee: Minnesota Mining and Manufacturing CompanyInventors: Thomas D. Krech, David C. May
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Patent number: 4418110Abstract: Retroreflective sheeting in which a specularly reflective layer within the sheeting has extensive discontinuities which make the sheeting permeable to vapor, thereby allowing release of vapors from a substrate to which the sheeting is applied.Type: GrantFiled: June 21, 1982Date of Patent: November 29, 1983Assignee: Minnesota Mining and ManufacturingInventors: David C. May, Terry R. Bailey
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Patent number: 4348397Abstract: There is provided a method of enhancing the retention of dyphylline in the human system. Dyphylline is a known bronchodilator whose pharmacological utility has been considerably restricted by its short in vivo half life. The retention of dyphylline in the system has been enhanced by coadministration of probenecid. The utility of dyphylline in asthma therapy is therefore considerably enhanced.Type: GrantFiled: March 23, 1981Date of Patent: September 7, 1982Assignee: Research CorporationInventors: David C. May, Charles H. Jarboe
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Patent number: D311704Type: GrantFiled: June 30, 1988Date of Patent: October 30, 1990Assignee: Minnesota Mining and Manufacturing CompanyInventor: David C. May