# US 11,896,238 B2 · Method of converting bone stock into bone chips > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,896,238 B2 - Document ID: US11896238B2 - Status: Granted - Kind: B2 - Application number: 17/098,762 - Filed: 2020-11-16 - Published: 2021-03-04 - Granted: 2024-02-13 - Earliest claimed: 2007-11-07 - Assignees: Stryker Corporation - Applicants: Stryker Corporation - Inventors: Richard Burmeister; Gary Kalinka; Michael Peterson - Web page: https://patentgrep.com/patent/US11896238B2 ## CPC - A61B 17/1615: {Drill bits, i.e. rotating tools extending from a handpiece to contact the worked material} - A61F 2/4644: {Preparation of bone graft, bone plugs or bone dowels, e.g. grinding or milling bone material (bone material A61F2/28; disintegrating or milling devices B02C)} - B02C 18/16: Details - B02C 18/22: Feed or discharge means - B02C 18/24: Drives - A61B 2017/1602: {Mills} - A61F 2002/4645: {Devices for grinding or milling bone material} - A61F 2002/4646: {Devices for cleaning bone graft} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C) - B02C: CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN ({household tools and machines for pulverising foodstuffs, e.g. coffee and spice mills A47J42/00; pharmaceutical mortars A61J3/02; mechanical processing of refuse and garbage B03B9/06; dressing mould materials by grinding B22C5/04}; obtaining metallic powder by crushing, grinding or milling B22F9/04; {recovery of plastics by disintegrating B29B17/00; crushing raw materials in starch making C08B30/02; beaters for papermaking D21D1/02; crushing devices specially for transport in mines E21F13/002; slag crushing devices F23J1/00; fuel milling devices in combustion apparatus F23K1/00; household devices for crushing coal F24B15/02; ice disintegrating devices F25C5/02}) ## Abstract A mill head for replaceable attachment to a base so as to collectively form a bone mill. The mill head includes shell with: a first opening in which bone stock is introduced into the head; and a second opening through which the bone chips are discharged. A cutting device is mounted in the shell to both rotate and move laterally. Attached to the cutting device are coupling features for engaging a drive spindle able to rotate the cutting device. Also attached to the housing is an alignment feature. The alignment feature engages a complementary alignment feature associated with the drive spindle so as a result of the engagement of the alignment features, the cutting device moves within the shell so that the cutting device coupling features are positioned to engage the drive spindle. ## Claims ### Claim 1 A mill head for converting bone stock into bone chips and for use with a base unit, said mill head comprising: a housing having: an inlet opening into which bone stock is introduced into said housing; an outlet opening spaced away from said inlet opening; and a cutting device mounted in said housing between said inlet opening and said outlet opening; and a plunger moveably mounted in said inlet opening to push bone stock against said cutting device to convert bone stock into bone chips and discharge bone chips through said outlet opening; wherein said cutting device is further defined as a cutting disc having a plurality of cutting scallops, each scallop being monolithic with said cutting disc and each scallop defining an opening and having a scallop top surface and a scallop bottom surface which meet at a cutting edge of said scallop; and wherein said cutting disc has a plurality of equangularly spaced apart openings that are centered around and spaced outwardly from a center of said cutting disc, with said equangularly spaced apart openings configured to engage the base unit such that rotational force from the base unit results in the like rotation of said cutting device, the equangularly spaced apart openings being configured to engage complimentary teeth on a drive spindle of the base unit. ### Claim 2 (depends on 1) The mill head of claim 1, wherein said plunger is slidably mounted to the top of said housing so that a bottom surface of said plunger is directed towards said cutting device. ### Claim 3 (depends on 1) The mill head of claim 1, wherein said plunger comprises a top plate dimensioned to subtend an area larger than a cross-sectional area of said inlet opening. ### Claim 4 (depends on 1) The mill head of claim 1, further including a tray removably attached to said housing adjacent said outlet opening for receiving bone chips discharged through said outlet opening. ### Claim 5 (depends on 1) The mill head of claim 1, wherein said cutting edge of each of said scallops is located in said housing between said inlet opening and said outlet opening such that said cutting device strikes the bone stock and chips are cut from the bone stock with said cutting edge and subsequently move through said opening defined by said scallop. ### Claim 6 (depends on 1) The mill head of claim 1, wherein said cutting disc is further formed to have an opening in the center of said disc. ### Claim 7 A system for converting bone stock into bone chips, said system comprising: a mill head comprising: a housing having an inlet opening into which bone stock is introduced into the housing and an outlet opening spaced away from the inlet opening; a cutting device mounted in the housing between the inlet opening and the outlet opening; and a plunger moveably mounted in the inlet opening to push bone stock against the cutting device to convert bone stock into bone chips and the discharge of bone chips through the outlet opening; and a base unit having a motor and a drive spindle configured to transfer torque developed by the motor to the cutting device; wherein the cutting device is further defined as a cutting disc formed to have a plurality of equangularly spaced apart openings that are centered around and spaced outwardly from the center of the cutting disc that function to couple the cutting disc with the drive spindle, and wherein the equangularly spaced apart openings are configured to engage complimentary teeth on the drive spindle of the base unit so that rotation of the drive spindle results in the like rotation of the cutting device. ### Claim 8 (depends on 7) The system of claim 7, further including a tray removably attached to the housing adjacent the outlet opening for receiving bone chips discharged through the outlet opening. ### Claim 9 (depends on 7) The system of claim 7, wherein the cutting device has at least one cutting edge located in the housing between the inlet opening and the outlet opening such that the cutting device strikes the bone stock and chips are cut from the bone stock with the cutting edge and subsequently move through the outlet opening and are discharged. ### Claim 10 (depends on 7) The system of claim 7, wherein the cutting disc has a plurality of cutting scallops, each scallop defining the opening and having a scallop top surface and a scallop bottom surface which meet at a cutting edge of the scallop. ### Claim 11 (depends on 7) The system of claim 7, wherein the base unit comprises a spring that places a force on the drive spindle and the seating of the mill head results in at least some retraction of the spindle towards into the base unit until the teeth on the drive spindle spring into the equangularly spaced apart openings in the cutting disc. ### Claim 12 (depends on 7) The system of claim 7, wherein the cutting disc is further formed to have an opening in the center of the disc that functions to align the cutting disc with the drive spindle. ### Claim 13 (depends on 11) The system of claim 11, wherein the drive spindle has an alignment pin located to engage the opening so that the engagement of the alignment pin results in the lateral positioning of the cutting device so that the at least one tooth on the drive spindle can engage the at least one opening on the cutting device and rotate the cutting device. ### Claim 14 (depends on 7) The system of claim 7, further including a locking assembly for releasably holding the housing of the mill head to the base unit. ### Claim 15 (depends on 14) The system of claim 14, wherein pedestal teeth on the base unit seat in notches in the mill head, wherein as a consequence of the pedestal teeth seating in the mill head notches, the pedestal teeth inhibit the transfer of the rotational movement of the cutting device to the rest of the mill and thus perform rotation-stopping effect. ### Claim 16 A system for converting bone stock into bone chips, said system comprising: a mill head comprising: a housing having an inlet opening into which bone stock is introduced into the housing and an outlet opening spaced away from the inlet opening; a cutting device mounted in the housing between the inlet opening and the outlet opening; and a plunger moveably mounted in the inlet opening to push bone stock against the cutting device to convert bone stock into bone chips and the discharge of bone chips through the outlet opening; a base unit having a motor and a drive spindle configured to transfer torque developed by the motor to the cutting device; and a locking assembly for releasably holding the housing of the mill head to the base unit; wherein pedestal teeth on the base unit seat in notches in the mill head, wherein as a consequence of the pedestal teeth seating in the mill head notches, the pedestal teeth inhibit the transfer of rotational movement of the cutting device to the rest of the mill and thus perform rotation-stopping effect.