US3921340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic head surface formation apparatus and method
Assignee: International Business Machines Corp
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Filing: 1974-03-11
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Granted: 1975-11-25
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Expires: 1994-03-11
Abstract
Abstract A head is moved toward and rotated against an abrasive while its resistance is monitored by a four-lead bridge. Two leads from the head are connected to two slip rings, and each slip ring has two pairs of brushes, each wire from the bridge going to a different brush pair. Head movement toward the abrasive is terminated when a predetermined head resistance is detected by the bridge.
Inventors
- 👤 Larry A Johnson
- 👤 Neil L Robinson
- 👤 Richard H Strang
- 👤 Gary G Vair
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:07
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
257 words
Apparatus for forming the surface contour of a multi-lead single-track magnetic head element having a portion, removed during surface formation, which has an electrical characteristic monitorable through said leads, comprising: an abrasive material shaped to include a complement of the surface contour to be formed; a continuously rotatable armature for fixedly retaining the magnetic head, said armature being axially movable to bring the head surface into contact with the abrasive material; a plurality of slip rings, one for each head lead, fastened to the rotatable armature and rotated therewith; a plurality of conductors for connecting each slip ring to a different head lead; a support, stationary with respect to the armature, including a brush surface coextensive and adjacent the slip rings; a plurality of electrical brushes mounted about the support brush surface, so that each brush contacts a slip ring, there being more brushes than slip rings and more than one brush contacting each slip ring; a resistance detector, having at least four input terminals for each unknown resistance; conductors interconnecting the brushes and the detector''s input terminals to present electrical characteristic of aforesaid head portion to the detector as a portion of an unknown resistance; monitoring means, connected to the resistance detector for generating a stop signal when the resistance detector detects a predetermined resistance; and control means connected to said rotatable armature and to said monitoring means operable by an external start signal to initiate rotation and axial movement of the armature and operable upon the occurreNce of a stop signal to terminate axial movement.
Claim 2
Dependent Claim
257 words
Apparatus for forming the surface contour of a multi-lead single-track magnetic head element having a portion, removed during surface formation, which has an electrical characteristic monitorable through said leads, comprising: an abrasive material shaped to include a complement of the surface contour to be formed; a continuously rotatable armature for fixedly retaining the magnetic head, said armature being axially movable to bring the head surface into contact with the abrasive material; a plurality of slip rings, one for each head lead, fastened to the rotatable armature and rotated therewith; a plurality of conductors for connecting each slip ring to a different head lead; a support, stationary with respect to the armature, including a brush surface coextensive and adjacent the slip rings; a plurality of electrical brushes mounted about the support brush surface, so that each brush contacts a slip ring, there being more brushes than slip rings and more than one brush contacting each slip ring; a resistance detector, having at least four input terminals for each unknown resistance; conductors interconnecting the brushes and the detector''s input terminals to present electrical characteristic of aforesaid head portion to the detector as a portion of an unknown resistance; monitoring means, connected to the resistance detector for generating a stop signal when the resistance detector detects a predetermined resistance; and control means connected to said rotatable armature and to said monitoring means operable by an external start signal to initiate rotation and axial movement of the armature and operable upon the occurreNce of a stop signal to terminate axial movement.
Claim 3
Dependent Claim
28 words
The apparatus of claim 1 wherein there are provided two head leads, two slip rings connected thereto and eight brushes, each slip ring being contacted by four brushes.
Claim 4
Dependent Claim
57 words
The apparatus of claim 2 wherein the resistance detector has a pair of voltage input terminals and a pair of current input terminals, the voltage input terminals being connected to two brushes contacting each of the two slip rings and the current input terminals being connected to two different brushes contacting each of the two slip rings.
Claim 5
Dependent Claim
29 words
The apparatus of claim 1 wherein the magnetic head includes a highly conductive section and a magnetoresistive section and there are provided two head leads connected to both sections.
Claim 6
Dependent Claim
28 words
The apparatus of claim 4 wherein there are provided two head leads, two slip rings connected thereto and eight brushes, each slip ring being contacted by four brushes.
Claim 7
Dependent Claim
57 words
The apparatus of claim 5 wherein the resistance detector has a pair of voltage input terminals and a pair of current input terminals, the voltage input terminals being connected to two brushes contacting each of the two slip rings and the current input terminals being connected to two different brushes contacting each of the two slip rings.
Claim 8
Dependent Claim
93 words
Apparatus for forming a single transducer having a portion, removed during fabrication, which has an electrical characteristic monitorable through connected leads, including in combination: a material, operable to remove the transducer portion during fabrication when the transducer and material are in contact; a rotatable armature for fixedly retaining the transducer; a plurality of slip rings fastened to the rotatable armature and rotated therewith; a plurality of conductors for connecting selected slip rings to selected transducer leads; and a plurality of electrical brushes mounted so that more than one brush contacts each slip ring.
Claim 9
Dependent Claim
93 words
Apparatus for forming a single transducer having a portion, removed during fabrication, which has an electrical characteristic monitorable through connected leads, including in combination: a material, operable to remove the transducer portion during fabrication when the transducer and material are in contact; a rotatable armature for fixedly retaining the transducer; a plurality of slip rings fastened to the rotatable armature and rotated therewith; a plurality of conductors for connecting selected slip rings to selected transducer leads; and a plurality of electrical brushes mounted so that more than one brush contacts each slip ring.
Claim 10
Dependent Claim
105 words
The apparatus of claim 7, further including: a resistance detector, having more than two input terminals; conductors interconnecting the brushes and the detector''s input terminals to present electrical characteristic of aforesaid head portion to the detector; monitoring means, connected to the resistance detector for generating a stop signal when the resistance detector detects a predetermined resistance; and control means connected to said rotatable armature and to said monitoring means operable by an external start signal to initiate rotation of the armature and contact between the transducer and material and operable upon the occurrence of a stop signal to terminate contact between the transducer and material.
Claim 11
Dependent Claim
98 words
A machine for fabricating a transducer having a portion, removed during fabrication, which has an electrical characteristic monitorable through connected leads, comprising in combination: a material, operable to remove the transducer portion during fabrication when the transducer and material are in contact; a fixture for retaining the transducer and rotating the transducer about an axis through aforesaid transducer portion; a plurality of contact surfaces; a plurality of electrical contacts arranged so that more than one contact contacts each contact surface; an output; and means for connecting transducer leads to the output through the contact surfaces and the contacts.
Claim 12
Dependent Claim
98 words
A machine for fabricating a transducer having a portion, removed during fabrication, which has an electrical characteristic monitorable through connected leads, comprising in combination: a material, operable to remove the transducer portion during fabrication when the transducer and material are in contact; a fixture for retaining the transducer and rotating the transducer about an axis through aforesaid transducer portion; a plurality of contact surfaces; a plurality of electrical contacts arranged so that more than one contact contacts each contact surface; an output; and means for connecting transducer leads to the output through the contact surfaces and the contacts.
Claim 13
Dependent Claim
97 words
The combination of claim 9, further including: a detector, having more than two input terminals; conductors interconnecting aforesaid output and the detector''s input terminals to present the electrical characteristic of aforesaid head portion to the detector; monitoring means, connected to the detector for generating a stop signal when the detector detects a predetermined value; and control means connected to said fixture and to said monitoring means operable by an external start signal to initiate contact between the transducer and material and opErable upon the occurrence of a stop signal to terminate contact between the transducer and material.
Claim 14
Dependent Claim
64 words
The combination comprising, during manufacturing of a transducer: a material removing device; a fully rotatable transducer operable to contact the material removing device, having a plurality of leads depending therefrom; a plurality of slip rings, one connected to each lead of the transducer; a plurality of brushes in contact with each slip ring; and a resistance measuring device having inputs connected to said brushes.
Claim 15
Dependent Claim
64 words
The combination comprising, during manufacturing of a transducer: a material removing device; a fully rotatable transducer operable to contact the material removing device, having a plurality of leads depending therefrom; a plurality of slip rings, one connected to each lead of the transducer; a plurality of brushes in contact with each slip ring; and a resistance measuring device having inputs connected to said brushes.
Claim 16
Dependent Claim
30 words
The combination of claim 11 wherein there is additionally provided a control means connected to the resistance measuring device for causing the transducer and material removing device to break contact.
Claim 17
Dependent Claim
66 words
Manufacturing apparatus including, during manufacturing: a material removing device; a transducer rotatable over more than a full turn, operable to contact the material removing device, having a plurality of leads depending therefrom; a plurality of contact surfaces; a plurality of contacts for each surface; a resistance measuring device having inputs; and conductors interconnecting the transducer leads and resistance measuring device through the contact surfaces and contacts.
Claim 18
Dependent Claim
66 words
Manufacturing apparatus including, during manufacturing: a material removing device; a transducer rotatable over more than a full turn, operable to contact the material removing device, having a plurality of leads depending therefrom; a plurality of contact surfaces; a plurality of contacts for each surface; a resistance measuring device having inputs; and conductors interconnecting the transducer leads and resistance measuring device through the contact surfaces and contacts.
Claim 19
Dependent Claim
30 words
The apparatus of claim 13 wherein there is additionally provided a control means connected to the resistance measuring device for causing the transducer and material removing device to break contact.
Claim 20
Independent Claim
83 words
A method for controlling the formation of the surface contour of a multi-lead magnetoresistive magnetic head; retaining and rotating the magnetic head about an axis through the contour during relative axial feeding of the head surface and an abrasive material; sensing the resistance of the head via slip rings connected to the head leads and a plurality of brushes contacting each slip ring; generating a stop signal when the resistance substantially equals a predetermined resistance; and terminating feeding when the stop signal occurs.
Claim 21
Independent Claim
83 words
A method for controlling the formation of the surface contour of a multi-lead magnetoresistive magnetic head; retaining and rotating the magnetic head about an axis through the contour during relative axial feeding of the head surface and an abrasive material; sensing the resistance of the head via slip rings connected to the head leads and a plurality of brushes contacting each slip ring; generating a stop signal when the resistance substantially equals a predetermined resistance; and terminating feeding when the stop signal occurs.
Claim 22
Independent Claim
65 words
A method for controlling the formation of the surface contour of a multi-lead magnetic head; rotating the magnetic head during axial feeding of the head surface and an abrasive material; sensing the resistance of the head through contact surfaces and a plurality of contacts for each surface; generating a signal when the resistance substantially equals a predetermined value; and terminating feeding when the signal occurs.
Claim 23
Independent Claim
65 words
A method for controlling the formation of the surface contour of a multi-lead magnetic head; rotating the magnetic head during axial feeding of the head surface and an abrasive material; sensing the resistance of the head through contact surfaces and a plurality of contacts for each surface; generating a signal when the resistance substantially equals a predetermined value; and terminating feeding when the signal occurs.
Claim 24
Dependent Claim
110 words
Apparatus for fabricating a single two lead transducer having a portion, removed during fabrication, which has an electrical characteristic monitorable through four detector leads including: a material, operable to remove the transducer portion during fabrication when the transducer and material are in contact; a rotatable armature for fixedly retaining the transducer; two slip rings fastened to the rotatable armature and rotated therewith; two conductors for connecting each slip ring to a different transducer lead; eight electrical brushes mounted so that two pairs of brushes contact each slip ring; a resistance detector, having four terminals; and four conductors interconnecting each pair of brushes to a different one of the detector''s terminals.
Claim 25
Dependent Claim
110 words
Apparatus for fabricating a single two lead transducer having a portion, removed during fabrication, which has an electrical characteristic monitorable through four detector leads including: a material, operable to remove the transducer portion during fabrication when the transducer and material are in contact; a rotatable armature for fixedly retaining the transducer; two slip rings fastened to the rotatable armature and rotated therewith; two conductors for connecting each slip ring to a different transducer lead; eight electrical brushes mounted so that two pairs of brushes contact each slip ring; a resistance detector, having four terminals; and four conductors interconnecting each pair of brushes to a different one of the detector''s terminals.
Claim 26
Dependent Claim
122 words
A machine for manufacturing a two lead transducer having a portion, removed during fabrication, which has an electrical characteristic monitorable through four connected detection leads, said machine including in combination: a material, operable to remove the transducer portion during fabrication when the transducer and material are in contact; a fixture for retaining the transducer and rotating the transducer about an axis through aforesaid transducer portion; two contact surfaces each connected to a different transducer lead; four pairs of electrical contacts arranged so that two pairs contact each contact surface and contacts in a pair are connected togetheR; a detector, having four detection terminals; and four conductors interconnecting each of the detector''s input terminals to a different one of the electrical contact pairs.
Claim 27
Dependent Claim
122 words
A machine for manufacturing a two lead transducer having a portion, removed during fabrication, which has an electrical characteristic monitorable through four connected detection leads, said machine including in combination: a material, operable to remove the transducer portion during fabrication when the transducer and material are in contact; a fixture for retaining the transducer and rotating the transducer about an axis through aforesaid transducer portion; two contact surfaces each connected to a different transducer lead; four pairs of electrical contacts arranged so that two pairs contact each contact surface and contacts in a pair are connected togetheR; a detector, having four detection terminals; and four conductors interconnecting each of the detector''s input terminals to a different one of the electrical contact pairs.
Claim 28
Dependent Claim
76 words
Manufacturing apparatus for forming the surface contour of a transducer by monitoring the resistance of the transducer while the transducer contacts a material removing device, comprising: a rotatable retainer for fixedly retaining the transducer and rotating the transducer more than 360*; at least two slip rings fastened to the retainer and connected to two electrical leads of said transducer; and at least eight electrical contacts connected together into four pairs, two pairs contacting each slip ring.
Claim 29
Dependent Claim
76 words
Manufacturing apparatus for forming the surface contour of a transducer by monitoring the resistance of the transducer while the transducer contacts a material removing device, comprising: a rotatable retainer for fixedly retaining the transducer and rotating the transducer more than 360*; at least two slip rings fastened to the retainer and connected to two electrical leads of said transducer; and at least eight electrical contacts connected together into four pairs, two pairs contacting each slip ring.
Claim 30
Dependent Claim
34 words
The manufacturing apparatus of claim 19 further including: a resistance detector, having at least four terminals; and at least four conductors interconnecting each pair of contacts and a different one of the detector''s terminals.
Claim 31
Dependent Claim
33 words
The manufacturing apparatus of claim 20 further including: control means connected to said retainer operable to terminate contact between the transducer and material removing device when the resistance detector detects a predetermined resistance.
Claim 32
Dependent Claim
69 words
The combination including, during manufacture: a material removing device; a fully rotatable transducer operable to contact the material removing device, having at least two leads depending therefrom; at least two slip rings, one connected to each lead of the transducer; at least two pairs of brushes in contact with each slip ring; and a resistance measuring device having at least one input connected to each of said brush pairs.
Claim 33
Dependent Claim
69 words
The combination including, during manufacture: a material removing device; a fully rotatable transducer operable to contact the material removing device, having at least two leads depending therefrom; at least two slip rings, one connected to each lead of the transducer; at least two pairs of brushes in contact with each slip ring; and a resistance measuring device having at least one input connected to each of said brush pairs.
Claim 34
Dependent Claim
30 words
The combination of claim 22 wherein there is additionally provided a control means connected to the resistance measuring device for causing the transducer and material removing device to break contact.
References Cited (Backward Citations)
US2884746A
Cited
US3105288A
Cited
US3438155A
Cited
US3702042A
Cited
US3681682A
Cited
US3691695A
Cited
US3787638A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-24 | 1979-05-26 | 1979-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-24 | 1983-05-26 | 1983-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-24 | 1987-05-26 | 1987-11-25 | $7700.00 | Window Closed / Lapsed |