# US 2014/0022869 A1 · Micro-geophone > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0022869 A1 - Document ID: US20140022869A1 - Status: Published application - Kind: A1 - Application number: 13/553,546 - Filed: 2012-07-19 - Published: 2014-01-23 - Earliest claimed: 2012-07-19 - Assignees: Geospace Technologies Corporation - Inventors: DANIEL M. WOO - Web page: https://patentgrep.com/patent/US20140022869A1 ## CPC - G01V 1/183: {with moving magnet} - H04R 9/04: Construction, mounting, or centering of coil - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract A micro geophone having pole pieces do not extend out around the sides of the magnet, thereby allowing a reduced geophone diameter for a given magnet diameter. The pole pieces are adhesively bonded to the magnet using an adhesive, which may be made suitably electrically conductive by silver or nickel fillers or non-conductive by mica fillers such as borosilicate glass micro-spheres. Axial space is economized by eliminating traditional spider retaining rings. The spider springs are seated directly against the coil form and secured by adhesive fillets disposed on the outward-facing spring circumferences. The spider springs include circumferential notches to receive adhesive. A two-piece bimetallic coil form of aluminum and a heavier material, joined by adhesive, is provided. Headers are affixed to the housing within the seats by adhesive. A straight or rounded chamfer at each of the geophone ends allows the overall geophone dimensions to be maximized. ## Claims ### Claim 1 A geophone housing assembly comprising: a hollow cylindrical housing having a first end and coaxial inner and outer surfaces near the first end that define a nominal housing thickness (th); a first chamfer formed about the circumference of said first end at said outer surface; a circular recessed seat formed at said first end along the inner surface of said housing; and a circular end cap having first and second obverse parallel sides near the perimeter that define a nominal end cap thickness (tc), said end cap seated in said recessed seat. ### Claim 2 (depends on 1) The geophone housing assembly of claim 1 further comprising: a second chamfer formed about the perimeter of said end cap so as to align with said first chamfer. ### Claim 3 (depends on 2) The geophone housing assembly of claim 2 further comprising: an adhesive bond fastening said end cap to said housing. ### Claim 4 (depends on 2) The geophone housing assembly of claim 2 wherein: said first chamfer extends across greater than 30 percent of said nominal housing thickness (th). ### Claim 5 (depends on 2) The geophone housing assembly of claim 2 wherein: said first chamfer extends across greater than 50 percent of said nominal housing thickness (th). ### Claim 6 (depends on 2) The geophone housing assembly of claim 2 wherein: said second chamfer extends across greater than 30 percent of said nominal end cap thickness (tc). ### Claim 7 (depends on 2) The geophone housing assembly of claim 2 wherein: said second chamfer extends across greater than 50 percent of said nominal end cap thickness (tc). ### Claim 8 (depends on 2) The geophone housing assembly of claim 2 wherein: said first and second chamfers define a flat profile. ### Claim 9 (depends on 2) The geophone housing assembly of claim 2 wherein: said first and second chamfers define a rounded profile. ### Claim 10 A geophone comprising: a hollow cylindrical housing having a end and coaxial inner and outer surfaces near the first end that define a nominal housing thickness (th); a first chamfer formed about the circumference of said first end at said outer surface; a circular recessed seat formed at said first end along the inner surface of said housing; a circular end cap having first and second obverse parallel sides near the perimeter that define a nominal end cap thickness (tc), said end cap seated in said recessed seat; and an electromagnetic sensor assembly disposed within said housing. ### Claim 11 (depends on 10) The geophone of claim 10 further comprising: a second chamfer formed about the perimeter of said end cap so as to align with said first chamfer. ### Claim 12 (depends on 11) The geophone housing assembly of claim 11 further comprising: an adhesive bond fastening said end cap to said housing. ### Claim 13 (depends on 11) The geophone housing assembly of claim 11 wherein: said first chamfer extends across greater than 30 percent of said nominal housing thickness (th). ### Claim 14 The geophone housing assembly of claim wherein: said first chamfer extends across greater than 50 percent of said nominal housing thickness (th). ### Claim 15 (depends on 11) The geophone housing assembly of claim 11 wherein: said second chamfer extends across greater than 30 percent of said nominal end cap thickness (tc). ### Claim 16 (depends on 11) The geophone housing assembly of claim 11 wherein: said second chamfer extends across greater than 50 percent of said nominal end cap thickness (tc). ### Claim 17 (depends on 11) The geophone housing assembly of claim 11 wherein: said first and second chamfers define a flat profile. ### Claim 18 (depends on 11) The geophone housing assembly of claim 11 wherein: said first and second chamfers define a rounded profile.