US3986033A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switching device for an X-ray generator comprising a time switch
Assignee: US Philips Corp
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Filing: 1974-03-15
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Granted: 1976-10-12
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Expires: 1994-03-15
Abstract
Abstract The exposure time in X-ray generators comprising a high-voltage generator which is actuated on the primary side is shorter than the actuation time on the primary side. This is because the high-voltage on the secondary side can follow the voltage on the primary side only at a given delay due to the stray inductance of the transformer. The effective exposure time (i.e. the time during which the X-ray tube emits the desired radiation), consequently, is shorter than the exposure time which is adjusted on the control panel, the reduction also being dependent of the tube current. So as to achieve that the effective exposure time is equal to the exposure time adjusted on the control panel, means are provided which prolong the actuation time in dependence of the exposure current.
Inventors
- 👤 Heinz Mester
- 👤 Gerd Vogler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:24
CPC Classifications
H; H05; H05G; H05G1/00; H05G1/08; H05G1/26; H05G1/30; H05G1/38; H05G1/42
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
84 words
In a switching device for an x-ray generator of the type including a high voltage transformer for supplying current to the x-ray tube and a switching element connected in the transformer primary circuit, the improvement comprising a time switch for controlling the actuation time of the switching element wherein the actuation time of the switching element is longer than the exposure time, and means coupled to the time switch for prolonging the switching element actuation time as a function of the x-ray tube current.
Claim 2
Dependent Claim
84 words
In a switching device for an x-ray generator of the type including a high voltage transformer for supplying current to the x-ray tube and a switching element connected in the transformer primary circuit, the improvement comprising a time switch for controlling the actuation time of the switching element wherein the actuation time of the switching element is longer than the exposure time, and means coupled to the time switch for prolonging the switching element actuation time as a function of the x-ray tube current.
Claim 3
Dependent Claim
73 words
A switching device as claimed in claim 1 wherein the actuation time of the time switch is determined by a resistor means which is connected in a time circuit of the time switch, said resistor means comprising a first reaistor which can be adjusted by means of an adjusting member for the exposure time and a second resistor which can be adjusted by means of an adjusting member for the x-ray tube current.
Claim 4
Dependent Claim
30 words
A switching device as claimed in claim 2, characterized in that the second resistor can be adjusted in dependence on the x-ray tube exposure voltage and on the power consumption.
Claim 5
Dependent Claim
21 words
A switching device as claimed in claim 1 further comprising means for prolonging the actuation time by a constant time period.
Claim 6
Dependent Claim
82 words
A switching device as claimed in claim 1 wherein the time switch comprises a first time delay unit which supplies an output pulse at the end of the adjusted exposure time, and said actuation time prolonging means comprises a second time delay unit which supplies an output pulse at the end of a period of time which is proportional to the x-ray tube current, one of the time delay units being controlled by the output pulse of the other time delay unit.
Claim 7
Dependent Claim
53 words
A switching device as claimed in claim 5, characterized in that the second time delay unit comprises a generator which supplies an increasing signal in response to a start signal, the output pulse being generated when this increasing signal reaches the value of a signal which is proportional to the x-ray tube current.
Claim 8
Dependent Claim
20 words
A switching device as claimed in claim 6, further comprising means for superimposing a direct voltage on the increasing signal.
Claim 9
Dependent Claim
39 words
A switching device as claimed in claim 6 in which the output pulse of the second time delay unit starts the first time delay unit and the generator produces an increasing signal that increases according to a non-linear curve.
Claim 10
Dependent Claim
66 words
A switching device as claimed in claim 5 adapted to operate with an automatic exposure device, in which the output pulse of the second time delay unit starts the first time delay unit, a time indicator, means for applying the output pulse of the second time delay unit to start the time indicator which is stopped by a switch-off pulse generated by the automatic exposure device.
Claim 11
Dependent Claim
85 words
A timer for an x-ray generator of the type including a high voltage transformer for supplying current to the x-ray tube and a switching element connected in the transformer primary circuit, said timer comprising, a timing circuit for controlling the actuation time of the switching element, said timing circuit including means for setting the desired exposure time of the x-ray generator, and means coupled to the timing circuit for varying the actuation time of the switching element as a function of the x-ray tube current.
Claim 12
Dependent Claim
85 words
A timer for an x-ray generator of the type including a high voltage transformer for supplying current to the x-ray tube and a switching element connected in the transformer primary circuit, said timer comprising, a timing circuit for controlling the actuation time of the switching element, said timing circuit including means for setting the desired exposure time of the x-ray generator, and means coupled to the timing circuit for varying the actuation time of the switching element as a function of the x-ray tube current.
Claim 13
Dependent Claim
65 words
A timer as claimed in claim 10 wherein said timing circuit comprises a first timing member for setting the nominal exposure time, a second correction-time member for generating an output signal that is delayed in time as a function of the x-ray tube current, said first and second time members being connected in cascade, and means coupling the correction-time member to the time varying means.
Claim 14
Dependent Claim
43 words
A timer as claimed in claim 10 wherein said time varying means comprises means coupled to an adjusting member for the x-ray tube current for varying an electric circuit element of the timing circuit that controls the actuation time of the switching element.
References Cited (Backward Citations)
US2668909A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-10-12 | 1980-04-12 | 1980-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-12 | 1984-04-12 | 1984-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-12 | 1988-04-12 | 1988-10-12 | $7700.00 | Window Closed / Lapsed |