Patent US4559812A successfully refreshed from Google Patents.
US4559812A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rheometer and method of use thereof
Assignee: SPRI Ltd SONDES PLACE DOKING SURREY RH4 3EF ENGLAND A BRITISH Co
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Filing: 1984-06-08
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Granted: 1985-12-24
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Expires: 2004-06-08
Abstract
Abstract A rheometer of the type which includes a chamber (26) in which, in use, a sample of rubber or of a synthetic elastomer which is to be tested is held under pressure in contact with a rotor (27), and means for measuring torque applied to the rotor (27) as it is rotated in contact with the sample, is provided with a driving mechanism (35) for rotating the rotor (27) driven by two pulse-operated electric stepping motors (40, 41) operating through pinions (44, 49) and a differential gear (46). The use of two stepping motors (40, 41) and the differential gear (46) enables the rheometer to test the sample in various ways. Firstly the rotor (27) may be rotated in one direction to strain the sample beyond its maximum recovery and then be rotated in a reverse direction step by step until there is zero torque on the rotor and the total reverse rotation then indicates the total angular recovery of the sample. Alternatively the rotor may be rotated continuously in one direction and the varying torque upon it may be measured as the sample is vulcanized or cured as is done with a Mooney Viscometer. As another alternative, the rotor (27) may be oscillated by varying the speeds of the motors (40, 41) without stopping the motors and this provides test results similar to those produced by a rheometer of the oscillating disc type.
Inventors
- 👤 Terence J. Kitchen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:52
CPC Classifications
G; G01; G01N; G01N11/00; G01N11/10; G01N11/14
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
128 words
In a rheometer which includes means defining a chamber for holding a sample of material of which the properties are to be measured under pressure in said chamber, a rotor, said rotor including a surface in contact with said sample in said chamber, drive means for rotating said rotor, and torque measuring means for measuring torque applied to said rotor as it is rotated, the improvements comprising: said drive means being reversible, and including a pulse-operated electric stepping motor, gearing connecting said motor to said rotor, and circuit means for supplying electrical pulses to said motor to rotate said motor and thereby rotate said rotor, said drive means enabling said rotor to be rotated selectively in either direction in steps of not more than 20 minutes of arc.
Claim 2
Dependent Claim
128 words
In a rheometer which includes means defining a chamber for holding a sample of material of which the properties are to be measured under pressure in said chamber, a rotor, said rotor including a surface in contact with said sample in said chamber, drive means for rotating said rotor, and torque measuring means for measuring torque applied to said rotor as it is rotated, the improvements comprising: said drive means being reversible, and including a pulse-operated electric stepping motor, gearing connecting said motor to said rotor, and circuit means for supplying electrical pulses to said motor to rotate said motor and thereby rotate said rotor, said drive means enabling said rotor to be rotated selectively in either direction in steps of not more than 20 minutes of arc.
Claim 3
Dependent Claim
40 words
A rheometer as claimed in claim 1, in which said rotor is a disc, and further comprising means rotatably mounting said disc in said chamber in a position in which, in use, said disc is entirely surrounded by said sample.
Claim 4
Dependent Claim
45 words
A rheometer as claimed in claim 1, further comprising timing means operatively connected in said drive means, said timing means indicating the time taken for variations in the torque on said rotor to take place after said rotor has been rotated by said drive means.
Claim 5
Dependent Claim
29 words
A rheometer as claimed in claim 1, in which said motor and said gearing enable said rotor to be rotated in steps of 1.8 minutes of arc or less.
Claim 6
Dependent Claim
67 words
A rheometer as claimed in claim 1, in which said drive means incorporates means for selectively rotating said rotor step by step in one direction, step by step in a reverse direction and oscillating said rotor step by step by rotating said rotor through one or more steps in said one direction followed by rotation of said rotor through one or more steps in said opposite direction.
Claim 7
Dependent Claim
42 words
A rheometer as claimed in claim 5, in which said drive means includes first and second pulse-operated electric stepping motors, said circuit means includes means for supplying pulses selectively to said first and second motors and said gearing includes differential gearing means.
Claim 8
Dependent Claim
25 words
A rheometer as claimed in claim 1, in which said drive means includes only a single pulse-operated electric stepping motor, said single motor being reversible.
Claim 9
Dependent Claim
91 words
A rheometer as claimed in claim 1, in which said motor and said gearing are constructed as a unit, said unit having an output shaft connecting said bearing to said rotor, and further comprising means freely rotatably mounting said unit, a load cell forming said torque measuring means and means connecting said load cell to said unit to prevent rotation of said unit, whereby said load cell indicates a reaction torque on said unit when said rotor is being rotated and said load cell hence indicates the torque on said rotor.
Claim 10
Dependent Claim
109 words
A rheometer as claimed in claim 1, further comprising a housing, said housing including first and second parts which are separable from each other along a plane transverse to the axis of rotation of said rotor, said first and second parts enclosing said chamber there between, and further comprising a mechanism for clamping said parts of said housing together and for moving said part of said housing on the side of said plane remote from said drive means linearly away from said plane and tilting said part to provide access to said chamber and to said rotor for insertion and removal of said sample into and from said chamber.
Claim 11
Dependent Claim
188 words
In a method of measuring the recovery of a sample of rubber or of a synthetic elastomer, said method comprising the steps of inserting said sample under pressure into the chamber of a rheometer which includes a rotor which has a surface in contact with said sample in said chamber and has drive means by which it is rotatable and torque measuring means for measuring the torque applied to said rotor as it is rotated; rotating said rotor in one direction to apply a substantial angular shear strain to said sample, said angular shear strain being greater than the maximum angular recovery of said sample; stopping the rotation of said rotor in said one direction; rotating said rotor in a reverse direction step by step through predetermined angles; observing the torque, as indicated by said torque measuring means, applied to said rotor by said sample as said sample recovers after each step of said reverse rotation; and then rotating said rotor through a further step until said observed torque falls to zero at which time the reverse rotation of said rotor indicates the angular recovery of said sample.
Claim 12
Dependent Claim
188 words
In a method of measuring the recovery of a sample of rubber or of a synthetic elastomer, said method comprising the steps of inserting said sample under pressure into the chamber of a rheometer which includes a rotor which has a surface in contact with said sample in said chamber and has drive means by which it is rotatable and torque measuring means for measuring the torque applied to said rotor as it is rotated; rotating said rotor in one direction to apply a substantial angular shear strain to said sample, said angular shear strain being greater than the maximum angular recovery of said sample; stopping the rotation of said rotor in said one direction; rotating said rotor in a reverse direction step by step through predetermined angles; observing the torque, as indicated by said torque measuring means, applied to said rotor by said sample as said sample recovers after each step of said reverse rotation; and then rotating said rotor through a further step until said observed torque falls to zero at which time the reverse rotation of said rotor indicates the angular recovery of said sample.
Claim 13
Dependent Claim
55 words
A method as claimed in claim 10, further comprising the step of measuring the time taken after each step of reverse rotation of said rotor for the torque on said rotor to increase to a maximum in said reverse direction or to fall to zero after said last step of reverse rotation has taken place.
Claim 14
Dependent Claim
67 words
A method as claimed in claim 11, further comprising a step of again rotating said rotor in said one direction through one or more steps after said last step of reverse rotation has taken place and said observed torque has fallen to zero, said rotation in said one direction being continued until a minimum observable torque in said reverse direction is indicated by said torque measuring means.
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) | 1988-12-23 | 1989-06-24 | 1989-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-23 | 1993-06-24 | 1993-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-23 | 1997-06-24 | 1997-12-24 | $7700.00 | Window Closed / Lapsed |