# US 2018/0318948 A1 · Manufacturing method for compound screw and manufacturing program for compound screw > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0318948 A1 - Document ID: US20180318948A1 - Status: Published application - Kind: A1 - Application number: 15/773,712 - Filed: 2016-11-07 - Published: 2018-11-08 - Earliest claimed: 2015-11-05 - Assignees: NejiLaw Inc. - Applicants: Nejilaw Inc. - Inventors: Hiroshi MICHIWAKI - Web page: https://patentgrep.com/patent/US20180318948A1 ## CPC - B23G 1/32: by milling - B23G 1/00: Thread cutting; Automatic machines specially designed therefor - B23G 3/00: Arrangements or accessories for enabling machine tools not specially designed only for thread cutting to be used for this purpose, e.g. arrangements for reversing the working spindle - B23Q 15/00: Automatic control or regulation of feed movement, cutting velocity or position of tool or work - B23Q 15/007: while the tool acts upon the workpiece - F16B 39/30: Locking exclusively by special shape of the screw-thread - G05B 19/18: Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of program data in numerical form (G05B19/418 takes precedence) - G05B 19/186: {Generation of screw- or gearlike surfaces} - B23G 2210/24: Threads having a variable pitch - B23G 2210/48: Threads having a special form or profile not otherwise provided for - F16B 2033/025: {with left-hand thread} - G05B 2219/49196: Screw - B23G: THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH (making helical grooves by turning B23B5/48, by milling B23C3/32, by forging, pressing, or hammering B21K1/56, by grinding B24B19/02; arrangements for copying or controlling B23Q; thread-forming by corrugating tubes B21D15/04, by rolling B21H3/02) - B23Q: DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING (tools of the kind used in lathes or boring machines B23B27/00); MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT - F16B: DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING (couplings for transmitting rotation F16D) - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) ## Abstract Provided is a manufacturing method for a compound screw having a first thread groove and a second thread groove with a different lead angle or lead direction from the first thread groove, wherein at least a portion of the first thread groove is formed by feeding a threading tool that acts on a workpiece a first feed amount toward the workpiece, the workpiece being a rotating object to be machined. Additionally, at least a portion of the second thread groove is formed by feeding the threading tool that acts on the workpiece a second feed amount that differs from the first feed amount. With these steps, a compound thread portion is formed in the workpiece. As a result, it is possible to mass produce a compound screw having two thread structures of differing lead angles and/or lead directions with a high level of quality. ## Claims ### Claim 1 A compound screw manufacturing method of manufacturing a compound screw having a first thread groove and a second thread groove with a different lead angle and/or lead direction from the first thread groove, the compound screw manufacturing method comprising: a first thread groove forming step of forming at least a portion of a first thread groove by a first threading path obtained by feeding a threading tool that acts on a workpiece to be machined a first feed amount in a feed direction practically parallel to a rotation axis, the workpiece rotating about a predetermined axis as the rotation axis; and a second thread groove forming step of forming at least a portion of a second thread groove by a second threading path obtained by feeding the threading tool that acts on the workpiece a second feed amount in the feed direction practically parallel to the rotation axis, the second feed amount differing from the first feed amount. ### Claim 2 A compound screw manufacturing method of manufacturing a compound screw having a first thread groove and a second thread groove with a different lead angle and/or lead direction from the first thread groove, the compound screw manufacturing method comprising: a first thread groove forming step of forming at least a portion of a first thread groove by a first threading path obtained by feeding a threading tool that acts on a workpiece to be machined in a first feed direction practically parallel to a rotation axis, the workpiece rotating in a first direction about a predetermined axis as the rotation axis; and a second thread groove forming step of forming at least a portion of a second thread groove by a second threading path obtained by feeding the threading tool that acts on the workpiece in the first feed direction, the workpiece rotating in a reverse direction of the first direction. ### Claim 3 A compound screw manufacturing method of manufacturing a compound screw having a first thread groove and a second thread groove with a different lead angle and/or lead direction from the first thread groove, the compound screw manufacturing method comprising: a first thread groove forming step of forming at least a portion of a first thread groove by a first threading path obtained by feeding a threading tool that acts on a workpiece to be machined in a first feed direction practically parallel to a rotation axis, the workpiece rotating in a first direction about a predetermined axis as the rotation axis; and a second thread groove forming step of forming at least a portion of a second thread groove by a second threading path obtained by feeding the threading tool that acts on the workpiece in a reverse direction of the first feed direction, the workpiece rotating in the same direction as the first direction. ### Claim 4 (depends on 3) The compound screw manufacturing method of claim 3, further comprising: a circumferential groove forming step of machining a groove that circles in a direction orthogonal to the axis, at a machining start position by the second thread groove forming step on the workpiece. ### Claim 5 (depends on 1) The compound screw manufacturing method of claim 1, wherein at least one of the first thread groove forming step and the second thread groove forming step is performed multiple times. ### Claim 6 (depends on 1) The compound screw manufacturing method of claim 1, wherein the second thread groove forming step is performed at any time while the first thread groove forming step is being performed multiple times. ### Claim 7 (depends on 1) The compound screw manufacturing method of claim 1, wherein the first thread groove forming step is performed at any time while the second thread groove forming step is being performed multiple times. ### Claim 8 (depends on 1) The compound screw manufacturing method of claim 1, wherein, when a plurality of consecutive first thread groove forming steps is defined as a first step group and a plurality of consecutive second thread groove forming steps is defined as a second step group, a plurality of first step groups and a plurality of second step groups are performed alternately. ### Claim 9 (depends on 1) The compound screw manufacturing method of claim 1, wherein the first thread groove forming step and the second thread groove forming step are performed alternately. ### Claim 10 (depends on 1) The compound screw manufacturing method of claim 1, wherein a threading cross-sectional area, cut by the first thread groove forming step, of a cross section including the rotation axis of the first thread groove decreases gradually or stepwise each time the first thread groove forming step is repeated multiple times, and a threading cross-sectional area, cut by the second thread groove forming step, of a cross section including the rotation axis of the second thread groove decreases gradually or stepwise each time the second thread groove forming step is repeated multiple times. ### Claim 11 A compound screw manufacturing program applied to a manufacturing apparatus for manufacturing a compound screw having a first thread groove and a second thread groove with a different lead angle and/or lead direction from the first thread groove, the compound screw manufacturing program configured to cause the manufacturing apparatus to perform: a first thread groove forming step of forming at least a portion of a first thread groove by a first threading path obtained by feeding a threading tool that acts on a workpiece to be machined a first feed amount in a feed direction practically parallel to a rotation axis, the workpiece rotating about a predetermined axis as the rotation axis, and a second thread groove forming step of forming at least a portion of a second thread groove by a second threading path obtained by feeding the threading tool that acts on the workpiece a second feed amount in the feed direction practically parallel to the rotation axis, the second feed amount differing from the first feed amount. ### Claim 12 A compound screw manufacturing program applied to a manufacturing apparatus for manufacturing a compound screw having a first thread groove and a second thread groove with a different lead angle and/or lead direction from the first thread groove, the compound screw manufacturing program configured to cause the manufacturing apparatus to perform: a first thread groove forming step of forming at least a portion of a first thread groove by a first threading path obtained by feeding a threading tool that acts on a workpiece to be machined in a first feed direction practically parallel to a rotation axis, the workpiece rotating in a first direction about a predetermined axis as the rotation axis, and a second thread groove forming step of forming at least a portion of a second thread groove by a second threading path obtained by feeding the threading tool that acts on the workpiece in the first feed direction, the workpiece rotating in a reverse direction of the first direction. ### Claim 13 A compound screw manufacturing program applied to a manufacturing apparatus for manufacturing a compound screw having a first thread groove and a second thread groove with a different lead angle and/or lead direction from the first thread groove, the compound screw manufacturing program configured to cause the manufacturing apparatus to perform: a first thread groove forming step of forming at least a portion of a first thread groove by a first threading path obtained by feeding a threading tool that acts on a workpiece to be machined in a first feed direction practically parallel to a rotation axis, the workpiece rotating in a first direction about a predetermined axis as the rotation axis, and a second thread groove forming step of forming at least a portion of a second thread groove by a second threading path obtained by feeding the threading tool that acts on the workpiece in a reverse direction of the first feed direction, the workpiece rotating in the same direction as the first direction. ### Claim 14 (depends on 3) The compound screw manufacturing method of claim 3, wherein at least one of the first thread groove forming step and the second thread groove forming step is performed multiple times. ### Claim 15 (depends on 3) The compound screw manufacturing method of claim 3, wherein the second thread groove forming step is performed at any time while the first thread groove forming step is being performed multiple times. ### Claim 16 (depends on 3) The compound screw manufacturing method of claim 3, wherein the first thread groove forming step is performed at any time while the second thread groove forming step is being performed multiple times. ### Claim 17 (depends on 3) The compound screw manufacturing method of claim 3, wherein, when a plurality of consecutive first thread groove forming steps is defined as a first step group and a plurality of consecutive second thread groove forming steps is defined as a second step group, a plurality of first step groups and a plurality of second step groups are performed alternately. ### Claim 18 (depends on 3) The compound screw manufacturing method of claim 3, wherein the first thread groove forming step and the second thread groove forming step are performed alternately. ### Claim 19 (depends on 3) The compound screw manufacturing method of claim 3, wherein a threading cross-sectional area, cut by the first thread groove forming step, of a cross section including the rotation axis of the first thread groove decreases gradually or stepwise each time the first thread groove forming step is repeated multiple times, and a threading cross-sectional area, cut by the second thread groove forming step, of a cross section including the rotation axis of the second thread groove decreases gradually or stepwise each time the second thread groove forming step is repeated multiple times.