Patent US4757170A successfully refreshed from Google Patents.
US4757170A
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US
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Method and apparatus for induction heating gears and similar workpieces
Assignee: Ajax Tocco Magnethermic Corp
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Filing: 1987-01-08
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Granted: 1988-07-12
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Expires: 2007-01-08
Abstract
Abstract A method and apparatus for progressively hardening an elongated workpiece having an outer generally cylindrical surface concentric with the central axis including the concept of providing closely spaced first and second induction heating coils each having workpiece receiving openings generally concentric with the axis of the workpiece; energizing the first coil with a low frequency such as a frequency less than about 50 KHz; energizing the second coil with a high radio frequency, such as the frequency exceeding 100 KHz; causing relatively axial and progessive motion between the workpiece and the first and second closely spaced coils in a direction entering the first coil and exiting the second coil whereby the cylindrical surface is progressively first preheated by the first coil and then immediately final heated by the second coil; and, then immediately quenching the cylindrical surface as it passes from the second coil whereby the cylindrical surface is progressively preheated, heated and quench hardened as the workpiece is moved through the induction heating coil.
Inventors
- 👤 George M. Mucha
- 👤 Donald E. Novorsky
- 👤 George D. Pfaffmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:19
CPC Classifications
C; C21; C21D; C21D9/00; C21D9/32
Claims Analysis
Total Claims: 59
Claim 1
Independent Claim
196 words
A method of hardening the radially protruding convoluted surfaces of a generally circuit workpiece adapted to rotate about a central axis generally concentric with said convoluted surfaces, said surfaces defining an inner or outer radial extreme circle by the tips of said convoluted surfaces, said method comprising the steps of: a. providing first and second closely spaced, coaxially aligned induction heating inductors having circular surfaces generally matching said radial extreme circle; b. energizing said first inductor with a first alternating frequency current of less than 50 KHz; c. energizing said second inductor with a second alternating frequency current or more than about 100 KHz; d. moving said workpiece along its central axis progressively said simultaneously through said first and second inductors in a given direction from said first inductor to said second inductor and at a rate to simultaneously and progressively preheat said workpiece moving through said first inductor at a portion adjacent said radial extreme circle to a temperature below a quench hardening temperature, and finally heat said preheated workpiece portion progressively to a quench hardening temperature adjacent said surfaces only; and, e. progressively quenching said surfaces immediately following said final heating of said surface.
Claim 2
Independent Claim
196 words
A method of hardening the radially protruding convoluted surfaces of a generally circuit workpiece adapted to rotate about a central axis generally concentric with said convoluted surfaces, said surfaces defining an inner or outer radial extreme circle by the tips of said convoluted surfaces, said method comprising the steps of: a. providing first and second closely spaced, coaxially aligned induction heating inductors having circular surfaces generally matching said radial extreme circle; b. energizing said first inductor with a first alternating frequency current of less than 50 KHz; c. energizing said second inductor with a second alternating frequency current or more than about 100 KHz; d. moving said workpiece along its central axis progressively said simultaneously through said first and second inductors in a given direction from said first inductor to said second inductor and at a rate to simultaneously and progressively preheat said workpiece moving through said first inductor at a portion adjacent said radial extreme circle to a temperature below a quench hardening temperature, and finally heat said preheated workpiece portion progressively to a quench hardening temperature adjacent said surfaces only; and, e. progressively quenching said surfaces immediately following said final heating of said surface.
Claim 3
Dependent Claim
25 words
A method as defined in claim 1 wherein said rate provides a delay of less than 1.0 seconds between said preheat and said final heat.
Claim 4
Dependent Claim
23 words
A method as defined in claim 2 including the further step of: f. rotating said workpiece during said preheat and said final heat.
Claim 5
Dependent Claim
18 words
A method as defined in claim 3 wherein said first frequency is in the range of 1-10 KHz.
Claim 6
Dependent Claim
15 words
A method as defined in claim 4 wherein said second frequency is above 200 KHz.
Claim 7
Dependent Claim
31 words
A method as defined in claim 3 including the further step of: g. prior heating said portion of said workpiece adjacent to said radial extreme circle prior to said progressive preheat.
Claim 8
Dependent Claim
36 words
A method as defined in claim 6 wherein the prior heating step includes: h. progressively moving said workpiece along said central axis through an induction heating inductor energized at a frequency less than about 10 KHz.
Claim 9
Dependent Claim
46 words
A method as defined in claim 7 wherein said induction heating inductor for progressively prior heating is said first inductor and including the step of progressively moving said workpiece along said axis through said first induction heating inductor in a direction opposite to said given direction.
Claim 10
Dependent Claim
44 words
A method as defined in claim 7 wherein said induction heating inductor for progressively prior heating is a third induction heating inductor and including the step of progressively moving said workpiece along said axis through said third induction heating inductor in said given direction.
Claim 11
Dependent Claim
30 words
A method as defined in claim 7 wherein said quenching step involves forcing liquid from said second inductor toward said workpiece as said workpiece progressively exits from said second inductor.
Claim 12
Dependent Claim
23 words
A method as defined in claim 1 including the further step of: f. rotating said workpiece during said preheat and said final beat.
Claim 13
Dependent Claim
18 words
A method as defined in claim 11 wherein said first frequency is in the range of 1-10 KHz.
Claim 14
Dependent Claim
18 words
A method as defined in claim 1 wherein said first frequency is in the range of 1-10 KHz.
Claim 15
Dependent Claim
15 words
A method as defined in claim 13 wherein said second frequency is above 200 KHz.
Claim 16
Dependent Claim
15 words
A method as defined in claim 1 wherein said second frequency is above 200 KHz.
Claim 17
Dependent Claim
31 words
A method as defined in claim 1 including the further step of: f. prior heating said portion of said workpiece adjacent to said radial extreme circle prior to said progressive preheat.
Claim 18
Dependent Claim
35 words
A method as defined in claim 16 wherein prior heating step includes: g. progressively moving said workpiece along said central axis through an induction heating inductor energized at a frequency less than about 10 KHz.
Claim 19
Dependent Claim
46 words
A method as defined in claim 17 wherein said induction heating inductor for progressively prior heating is said first inductor and including the step of progressively moving said workpiece along said axis through said first induction heating inductor in a direction opposite to said given direction.
Claim 20
Dependent Claim
44 words
A method as defined in claim 17 wherein said induction heating inductor for progressively prior heating is a third induction heating inductor and including the step of progressively moving said workpiece along said axis through said third induction heating inductor in said given direction.
Claim 21
Dependent Claim
30 words
A method as defined in claim 1 wherein said. quenching step involves forcing liquid from said second inductor toward said workpiece as said workpiece progressively exits from said second inductor.
Claim 22
Independent Claim
128 words
A method of hardening the outer teeth surface of an axially elongated gear having a central axis and having a quench hardening temperature, said method comprising the steps of: a. progressively preheating in an axial direction a portion of said outer surface to a preheated temperature below said quench hardening temperature by a first induction heating coil energized at a first frequency of less than 50 KHz; b. simultaneously progressively finally heating said preheated portion of said outer surface in the same axial direction giving a finally heated portion at a temperature equal to or above said quench hardening temperature by a second induction heating coil energized at a second frequency of greater than 100 KHz; and c. progressively quench hardening said finally heated portion of said workpiece.
Claim 23
Independent Claim
128 words
A method of hardening the outer teeth surface of an axially elongated gear having a central axis and having a quench hardening temperature, said method comprising the steps of: a. progressively preheating in an axial direction a portion of said outer surface to a preheated temperature below said quench hardening temperature by a first induction heating coil energized at a first frequency of less than 50 KHz; b. simultaneously progressively finally heating said preheated portion of said outer surface in the same axial direction giving a finally heated portion at a temperature equal to or above said quench hardening temperature by a second induction heating coil energized at a second frequency of greater than 100 KHz; and c. progressively quench hardening said finally heated portion of said workpiece.
Claim 24
Dependent Claim
30 words
The method as defined in claim 21 wherein said progressive final heating follows said progressive preheating on said teeth surface by a short time of less than about 1.0 seconds.
Claim 25
Dependent Claim
44 words
The method as defined in claim 22 including the step of moving said gear with respect to said first and second heating coils at a rate to produce said short time between said progressing and simultaneous preheat and progressive final heat of said surface.
Claim 26
Dependent Claim
27 words
The method as defined in claim 23 including the further step of rotating said gear around said axis during said progressive preheat and simultaneous progressive final heat.
Claim 27
Dependent Claim
27 words
The method as defined in claim 22 including the further step of rotating said gear around said axis during said progressive preheat and simultaneous progressive final heat.
Claim 28
Dependent Claim
18 words
A method as defined in claim 22 wherein said first frequency is in the range of 1-10 KHz.
Claim 29
Dependent Claim
15 words
A method as defined in claim 26 wherein said second frequency is above 200 KHz.
Claim 30
Dependent Claim
15 words
A method as defined in claim 22 wherein said second frequency is above 200 KHz.
Claim 31
Dependent Claim
27 words
The method as defined in claim 21 including the further step of rotating said gear around said axis during said progressive preheat and simultaneous progressive final heat.
Claim 32
Dependent Claim
18 words
A method as defined in claim 21 wherein said first frequency is in the range of 1-10 KHz.
Claim 33
Dependent Claim
15 words
A method as defined in claim 30 wherein said second frequency is above 200 KHz.
Claim 34
Dependent Claim
15 words
A method as defined in claim 21 wherein said second frequency is above 200 KHz.
Claim 35
Dependent Claim
21 words
The method as defined in claim 21 including the step of heating said outer surface prior to said progressive preheating step.
Claim 36
Independent Claim
138 words
A method of hardening the outer cylindrical gear teeth surface of a gear having a core and a preselected axial length parallel to the central axis concentric said teeth surface including teeth and connecting roots and said surface having a quench hardening temperature, said method comprising the steps of: a. progressively preheating said surface at a given axial velocity along a moving first band sufficiently to heat said roots to a temperature greater than the temperature of said core but less than said quench hardening temperature; b. progressively final heating said surface at an axial position behind said first band and along a second moving band sufficiently to increase said preheated surface to a final temperature at said surface greater than or equal to said quench hardening temperature; and c. immediately and progressively quenching said final heated surface.
Claim 37
Independent Claim
138 words
A method of hardening the outer cylindrical gear teeth surface of a gear having a core and a preselected axial length parallel to the central axis concentric said teeth surface including teeth and connecting roots and said surface having a quench hardening temperature, said method comprising the steps of: a. progressively preheating said surface at a given axial velocity along a moving first band sufficiently to heat said roots to a temperature greater than the temperature of said core but less than said quench hardening temperature; b. progressively final heating said surface at an axial position behind said first band and along a second moving band sufficiently to increase said preheated surface to a final temperature at said surface greater than or equal to said quench hardening temperature; and c. immediately and progressively quenching said final heated surface.
Claim 38
Dependent Claim
22 words
The method as defined in claim 34 wherein said progressive preheating step is performed at a frequency less than about 50 KHz.
Claim 39
Dependent Claim
22 words
The method as defined in claim 35 wherein said progressive final heat is performed at a frequency greater than about 100 KHz.
Claim 40
Dependent Claim
22 words
The method as defined in claim 36 wherein said progressive final heat is performed at a frequency greater than about 100 KHz.
Claim 41
Dependent Claim
22 words
The method as defined in claim 35 wherein said progressive final heat is performed at a frequency greater than about 100 KHz.
Claim 42
Dependent Claim
30 words
The method as defined in claim 38 wherein said progressive final heating follows said progressive preheating on said teeth surface by a short time of less than about 1.0 seconds.
Claim 43
Dependent Claim
30 words
The method as defined in claim 35 wherein said progressive final heating follows said progressive preheating on said teeth surface by a short time of less than about 1.0 seconds.
Claim 44
Dependent Claim
22 words
The method as defined in claim 34 wherein said progressive final heat is performed at a frequency greater than about 100 KHz.
Claim 45
Dependent Claim
30 words
The method as defined in claim 34 wherein said progressive final heating follows said progressive preheating on said teeth surface by a short time of less than about 1.0 seconds.
Claim 46
Dependent Claim
32 words
The method as defined in claim 42 including the step of moving said gear along said axis at a rate to produce said short time and said progressive final heating and preheating.
Claim 47
Independent Claim
152 words
A method of progressively hardening an elongated steel workpiece having a quench hardening temperature and having an outer generally cylindrical surface concentric with a central axis, said method comprising the steps of: a. providing closely spaced first and second induction heating coils with workpiece receiving openings generally concentric with said axis: b. energizing coil with a low frequency; c. energizing said second coil with a high radio frequency; d. causing relative axial and progressive motion between said workpiece and said first and second coils in a direction entering from said first coil and exiting from said second coil whereby said cylindrical surface is progressively first preheated by said first coil to a temperature below said quench hardening temperature and immediately final heated by said second coil to a temperature greater than or equal to said quench hardening temperature; and e. immediately quenching said cylindrical surface as it passes from said second coil.
Claim 48
Independent Claim
152 words
A method of progressively hardening an elongated steel workpiece having a quench hardening temperature and having an outer generally cylindrical surface concentric with a central axis, said method comprising the steps of: a. providing closely spaced first and second induction heating coils with workpiece receiving openings generally concentric with said axis: b. energizing coil with a low frequency; c. energizing said second coil with a high radio frequency; d. causing relative axial and progressive motion between said workpiece and said first and second coils in a direction entering from said first coil and exiting from said second coil whereby said cylindrical surface is progressively first preheated by said first coil to a temperature below said quench hardening temperature and immediately final heated by said second coil to a temperature greater than or equal to said quench hardening temperature; and e. immediately quenching said cylindrical surface as it passes from said second coil.
Claim 49
Dependent Claim
32 words
A method as defined in claim 44 including the step of moving said workpiece at a rate producing a delay between said first and second coil of less than about 1.0 second.
Claim 50
Dependent Claim
22 words
A method as defined in claim 44 including the step of rotating said workpiece during said progressive preheating and progressive final heating.
Claim 51
Dependent Claim
15 words
A method as defined in claim 44 wherein said low frequency is between 1-50 KHz.
Claim 52
Dependent Claim
18 words
A method as defined in claim 44 wherein said high radio frequency is greater than about 100 KHz.
Claim 53
Dependent Claim
31 words
A method as defined in claim 44 including the further step of inductively preheating said cylindrical surface with a third induction heating coil axially aligned with said first and second coil.
Claim 54
Independent Claim
177 words
An apparatus progressively hardening an elongated workpiece having an outer generally cylindrical surface concentric with a central axis, said apparatus comprising first and second induction heating coils with workpiece receiving openings; means for mounting said coils in closely spaced relationship and with said openings generally concentric with said axis, said coils in said spaced relationship having a combined axial dimension less than the length of said elongated workpiece; means for energizing said first coil with a low frequency; means for energizing said second coil with a high radio frequency; means for causing relative axial and progressive motion between said workpiece and said first and second coils in a direction entering said first coil and exiting from said second coil whereby said cylindrical surface is progressively first preheated by said first coil to a temperature below a quench hardening temperature of said workpiece and immediately final heated by said second coil to a temperature greater than or equal to said quench hardening temperature; and, means for immediately quenching said cylindrical surface as it passes from said second coil.
Claim 55
Independent Claim
177 words
An apparatus progressively hardening an elongated workpiece having an outer generally cylindrical surface concentric with a central axis, said apparatus comprising first and second induction heating coils with workpiece receiving openings; means for mounting said coils in closely spaced relationship and with said openings generally concentric with said axis, said coils in said spaced relationship having a combined axial dimension less than the length of said elongated workpiece; means for energizing said first coil with a low frequency; means for energizing said second coil with a high radio frequency; means for causing relative axial and progressive motion between said workpiece and said first and second coils in a direction entering said first coil and exiting from said second coil whereby said cylindrical surface is progressively first preheated by said first coil to a temperature below a quench hardening temperature of said workpiece and immediately final heated by said second coil to a temperature greater than or equal to said quench hardening temperature; and, means for immediately quenching said cylindrical surface as it passes from said second coil.
Claim 56
Dependent Claim
31 words
An apparatus as defined in claim 50 including means for moving said workpiece at a rate producing a delay between said first and second coil of less than about 1.0 second.
Claim 57
Dependent Claim
21 words
An apparatus as defined in claim 50 including means for rotating said workpiece during said progressive preheating and progressive final heating.
Claim 58
Dependent Claim
21 words
An apparatus as defined in claim 50 including means for energizing said first coil at a low frequency between 1-50 KHz.
Claim 59
Dependent Claim
24 words
An apparatus as defined in claim 50 including means for energizing said second coil at a high radio frequency greater than about 100 KHz.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1991-07-12 | 1992-01-11 | 1992-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-12 | 1996-01-11 | 1996-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-12 | 2000-01-11 | 2000-07-12 | $7700.00 | Window Closed / Lapsed |