US3825811A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System and method for monitoring a press load
Assignee: Alcoa Corp
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Filing: 1973-02-26
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Granted: 1974-07-23
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Expires: 1993-02-26
Abstract
Abstract A system and method for monitoring the load on a forming press during its work cycle including a digital encoder operably connected by a servomechanism to a timing mechanism on the press so as to provide a digital output determinative of any given position of the press ram during its work cycle. A digital-toanalog converter converts the digital signal to an analog signal indicative of the ram position. The analog signal is directed to a function generator which is pre-programmed to produce a signal representative of a predetermined tolerable stress load on the press at such position of the press ram. This representative signal is compared to the actual stress load on the press, as measured by one or more strain sensing devices associated with the press, so as to produce a warning signal and/or to stop the press ram at a selected time in the work cycle when the actual load on the press exceeds the predetermined tolerable load for the system.
Inventors
- 👤 H Smith
- 👤 P Berka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:24
CPC Classifications
B; B30; B30B; B30B15/00; B30B15/0094; B30B15/28; B30B15/281
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
170 words
A system for controlling a press apparatus comprising, ram means including a ram mounted for a cyclical movement on the press structure, a rotating member operably connected to the ram whereby its degree of rotation is related to the ram position, a rotation sensing assembly operably connected to said rotating member for producing ram position signals in response to various ram positions, a first strain signal generating assembly for receiving said ram position signals and producing theoretical strain signals indicative of predetermined selective strain on the press structure at each position of the ram indicated by said ram position signals, the second strain signal generating assembly operably connected to the press structure for producing actual strain signals indicative of the actual strain on the press structure imparted by the ram at such various positions, and a comparative signal assembly for receiving and comparing the theoretical strain signals and the actual strain signals for producing an overload signal when the actual strain exceeds the predetermined selective strain at such various positions.
Claim 2
Independent Claim
170 words
A system for controlling a press apparatus comprising, ram means including a ram mounted for a cyclical movement on the press structure, a rotating member operably connected to the ram whereby its degree of rotation is related to the ram position, a rotation sensing assembly operably connected to said rotating member for producing ram position signals in response to various ram positions, a first strain signal generating assembly for receiving said ram position signals and producing theoretical strain signals indicative of predetermined selective strain on the press structure at each position of the ram indicated by said ram position signals, the second strain signal generating assembly operably connected to the press structure for producing actual strain signals indicative of the actual strain on the press structure imparted by the ram at such various positions, and a comparative signal assembly for receiving and comparing the theoretical strain signals and the actual strain signals for producing an overload signal when the actual strain exceeds the predetermined selective strain at such various positions.
Claim 3
Dependent Claim
49 words
A system in accordance with claim 1, wherein said first strain signal generating assembly comprises a function generator for modifying said ram position signals and producing theoretical strain signals corresponding to the rate load of said press at the positions of the ram indicated by the ram position signal.
Claim 4
Dependent Claim
33 words
A system in accordance with claim 1, wherein said rotation sensing assembly includes a shaft-position digital encoder for producing a digital output signal indicative of the degree of rotation of said rotating member.
Claim 5
Dependent Claim
37 words
A system in accordance with claim 3, including a digital-to-analog converter for receiving said digital output signal from said shaft-position digital encoder and for producing an analog ram position output signal indicative of the various ram positions.
Claim 6
Dependent Claim
71 words
A system in accordance with claim 1, wherein said rotation sensing assembly comprises a servo-generator operably connected to said rotating element, a servo motor having a rotating drive shaft for rotating a shaft position measuring device, and said servo motor being electrically connected to said servo generator such that the degree of rotation of said servo motor shaft is a reproduction of the rotation of the rotor of said servo generator.
Claim 7
Dependent Claim
65 words
A system in accordance with claim 1, wherein said rotating member comprises a crankshaft operably connected to said ram for moving said ram through its operating cycle, another rotating member supported for rotation on said press structure, an endless drive member entrained in driving relation about said rotating members, and said rotation sensing assembly operably connected to said other shaft for determining the ram position.
Claim 8
Dependent Claim
47 words
A system in accordance with claim 6, wherein said other rotating member comprises a rotary cam shaft mounted for rotation on said frame, and cam limit switches disposed for selective engagement with said rotary cam shaft for controlling the movement of said ram during its operating cycle.
Claim 9
Independent Claim
105 words
A method of controlling a press apparatus having a ram mounted for cyclical movement on a press structure comprising: mechanically sensing the location of the ram at various positions in its travel through its cycle, transforming the sensed locations into electrical signals proportional to the location, generating a signal for theoretical strain on the press apparatus at each such position of the ram, mechanically sensing the actual strain on the press apparatus at each of such positions of the ram, transforming the sensed strain to a signal proportional to such strain, and comparing the actual strain to the theoretical strain and marking the difference therebetween.
Claim 10
Independent Claim
105 words
A method of controlling a press apparatus having a ram mounted for cyclical movement on a press structure comprising: mechanically sensing the location of the ram at various positions in its travel through its cycle, transforming the sensed locations into electrical signals proportional to the location, generating a signal for theoretical strain on the press apparatus at each such position of the ram, mechanically sensing the actual strain on the press apparatus at each of such positions of the ram, transforming the sensed strain to a signal proportional to such strain, and comparing the actual strain to the theoretical strain and marking the difference therebetween.
Claim 11
Dependent Claim
43 words
A method according to claim 8, wherein the press includes a rotary element whose degree of rotation is proportional to the location of the ram in its cycle and wherein the mechanical sensing of the press location is performed by said rotary element.
Claim 12
Independent Claim
173 words
A system for controlling a press apparatus of the type including ram means including a ram mounted for cyclical movement on the press and a rotating member operably connected to the ram whereby its degree of rotation is related to the ram position comprising: a rotation sensing assembly operably connected to said rotating member for producing ram position signals in response to various ram positions, a first strain signal generating assembly for receiving said ram position signals and producing theoretical strain signals indicative of predetermined selective strain on the press structure at each position of the ram indicated by said ram position signals, a second strain signal generating assembly operably connected to the press structure for producing actual strain signals indicative of the actual strain on the press structure imparted by the ram at such various positions, and a comparative signal assembly for receiving and comparing the theoretical strain signals and the actual strain signals for producing an overload signal when the actual strain exceeds the predetermined selective strain at such various positions.
Claim 13
Independent Claim
173 words
A system for controlling a press apparatus of the type including ram means including a ram mounted for cyclical movement on the press and a rotating member operably connected to the ram whereby its degree of rotation is related to the ram position comprising: a rotation sensing assembly operably connected to said rotating member for producing ram position signals in response to various ram positions, a first strain signal generating assembly for receiving said ram position signals and producing theoretical strain signals indicative of predetermined selective strain on the press structure at each position of the ram indicated by said ram position signals, a second strain signal generating assembly operably connected to the press structure for producing actual strain signals indicative of the actual strain on the press structure imparted by the ram at such various positions, and a comparative signal assembly for receiving and comparing the theoretical strain signals and the actual strain signals for producing an overload signal when the actual strain exceeds the predetermined selective strain at such various positions.
Claim 14
Independent Claim
151 words
A system for controlling a press apparatus comprising: a ram mounted for cyclical movement on the press structure, position sensing means for sensing various positions of the ram, transducer means for transducing the sensed ram positions to signals indicative of said ram positions, a first strain signal generating assembly for receiving said ram position signals and producing theoretical strain signals indicative of predetermined selective strain on the press structure at each position of the ram indicated by said ram position signals, a second strain signal generating assembly operably connected to the press structure for producing actual strain signals indicative of the actual strain on the press structure imparted by the ram at such various positions, and a comparative signal assembly for receiving and comparing the theoretical strain signals and the actual strain signals for producing an overload signal when the actual strain exceeds the predetermined selective strain at such various positions.
Claim 15
Independent Claim
151 words
A system for controlling a press apparatus comprising: a ram mounted for cyclical movement on the press structure, position sensing means for sensing various positions of the ram, transducer means for transducing the sensed ram positions to signals indicative of said ram positions, a first strain signal generating assembly for receiving said ram position signals and producing theoretical strain signals indicative of predetermined selective strain on the press structure at each position of the ram indicated by said ram position signals, a second strain signal generating assembly operably connected to the press structure for producing actual strain signals indicative of the actual strain on the press structure imparted by the ram at such various positions, and a comparative signal assembly for receiving and comparing the theoretical strain signals and the actual strain signals for producing an overload signal when the actual strain exceeds the predetermined selective strain at such various positions.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |