EP0019463A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Air dispensing apparatus
Assignee: Individual
•
Filing: 1980-05-15
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Granted: —
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Expires: 2000-05-15
Abstract
Abstract A control system, of the kind in which a transducer responsive to a variable quantity is responsible for initiating control effort to adjust the said quantity, is described with particular though not exclusive application to a system for obtaining precise inflation to a desired pressure setting of pneumatic tyres. A pressure transducer which provides an output voltage proportional to its input pressure determines the output frequency of a voltage/frequency converter. The output of the voltage/frequency converter is gated into a counter for a set period determined by a timer unit so that in such period the counter assembles a count which is a measure of the sensed pressure. Thetimer unit is adapted to divide down the local a.c. mains supply frequency so as to derive therefrom discrete timing pulses enabling cyclic operation of the apparatus within a predetermined timing framework. A user has the facility to enter a pressure target into the apparatus and, during each cyclic operation, a comparison is effected between the pressure sensed by the transducer and the set target pressure and, depending upon the outcome of this comparison, a pressure increment or decrement is affec- tuated as appropriate by operation of an inflate or exhaust valve. A modified embodiment having decoding and display modules coupled to the pressure counter constitutes an electronic pressure meter. Compensation for transducer and/or voltage/frequency converter drift is described, together with variants such as for enabling extra large tyres to be rapidly inflated, and alternative applications using for example temperature sensitive or mass sensitive transducers for temperature control or weighing/batching.
Inventors
- 👤 John Sansbury Knubley
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 14:20
CPC Classifications
G; G05; G05D; G05D16/00; G05D16/20; G05D16/2006; G05D16/2013; G05D16/2026; G05D16/2046; G05D16/2053; B; B60; B60S; B60S5/00; B60S5/04; B60S5/043; B60S5/046; G01; G01L; G01L17/00; H; H03; H03M; H03M1/00; H03M1/12; H03M1/60; Y; Y10; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2559; Y10T137/2574; Y10T137/2605; Y10T137/2607; Y10T137/3584; Y10T137/36; Y10T137/3662
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
118 words
A system comprising:- a transducer; converter means responsive to an output signal from said transducer for deriving a signal having a frequency which is a function of the transducer output signal; counter means coupled to the output of said converter means for counting excursions of the variable frequency signal produced thereby and providing output signals representative of the count accumulated; time control means associated with said counter means for determining periods during which the output of said converter means is counted by said counter means whereby the count accumulated during each of said periods constitutes a measure of the transducer output during the respective period; and utilization means responsive to the measures thus derived of the transducer output.
Claim 2
Independent Claim
118 words
A system comprising:- a transducer; converter means responsive to an output signal from said transducer for deriving a signal having a frequency which is a function of the transducer output signal; counter means coupled to the output of said converter means for counting excursions of the variable frequency signal produced thereby and providing output signals representative of the count accumulated; time control means associated with said counter means for determining periods during which the output of said converter means is counted by said counter means whereby the count accumulated during each of said periods constitutes a measure of the transducer output during the respective period; and utilization means responsive to the measures thus derived of the transducer output.
Claim 3
Dependent Claim
35 words
A system as claimed in claim 1 wherein said utilization means comprises display means adapted and arranged to provide a display of the count accumulated by the counter means during each of said time periods.
Claim 4
Dependent Claim
48 words
A sy:tem as claimed in claim 2 wherein said display means comprises decoder means responsive tc the output signals of the counter means and at least one visible display means coupled to the decoder means and adapted to provide a visible display corresponding to the decoded -utput signals.
Claim 5
Dependent Claim
61 words
A system as claimed in claim 3 wherein said counter means comprises at least one decade counter providing BCD output signals, said display means comprises at least one seven-segment LCD display device, and said decoder means is adapted to convert the BCD output of the decade counter into a corresponding input for actuating the respective segments of the seven-segment LCD display.
Claim 6
Independent Claim
62 words
A system according to any preceding claim wherein said utilization means comprises comparator means for comparing the count assembled in said counter means with a predetermined quantity, and control means responsive to the result of said comparison, and wherein the operations of said comparator means and of said control means are arranged to occur at times determined by said time control means.
Claim 7
Dependent Claim
22 words
A system according to claim 5 wherein said control means is adapted to adjust the quantity to which the transducer is exposed.
Claim 8
Dependent Claim
31 words
A system according to claim 6 wherein the transducer is pressure sensitive and the control means is adapted to govern the pressure within an environment which is monitored by said transducer.
Claim 9
Dependent Claim
54 words
A system according to claim 7 adapted for use as a vehicle tyre inflation apparatus and wherein said transducer is adapted to be made responsive to the air pressure within a tyre coupled to the apparatus and said control means comprise at least an air inlet valve for admitting compressed air to the tyre.
Claim 10
Dependent Claim
22 words
A system according to claim 8 wherein said control means further comprises an air exhaust valve for exhausting air from the tyre.
Claim 11
Dependent Claim
84 words
A system according to claim 8 wherein said time control means is adapted to generate a cyclic timing sequence during one part of each cycle of which a count is entered into the counter means so as to provide a measure therein of the transducer output and during anothrr part of each cycle of which the air inlet valve is opened in dependence upon the comparison effected by said comparator means with the said predetermined quantity which is representative of a desired tyre pressure.
Claim 12
Dependent Claim
38 words
A system according to claim 10 wherein each said cycle includes a period when the air inlet valve is not open and no count is entered into the counter means, said period enabling the system pressure to stabilize.
Claim 13
Dependent Claim
123 words
A system according to claim 10 or claim 11 wherein said comparator means is arranged to provide an output signal when the pressure sensed by the transducer is lower than the desired tyre pressure by a preset amount or less, and logic circuitry is provided responsive to said output signal for decreasing the duration of that part of each cycle during which the air inlet valve . is opened, the arrangement thus being such that a tyre will be inflated by the system in cyclic periods of opening of said air inlet valve and said periods will have a first duration until the tyre pressure is within a predetermined range of the desired tyre pressure and thereafter will have a second, lesser duration.
Claim 14
Dependent Claim
173 words
A system according to claim 9 wherein said time control means is adapted to generate a cyclic timing sequence, and during one part of each cycle of said sequence a count is entered into the counter means so as to provide therein a measure of the transducer output, and during another part of each cycle of said sequence a respective one of said air inlet and exhaust valves is opened in dependence upon the comparison effected by said comparator means with the said predetermined quantity which is representative of a desired tyre pressure, and wherein logic circuitry is provided responsive to outputs from said comparator means such that, in operation of the system, a tyre to be inflated is subjected to timing cycles during each of which said air inlet valve is opened for a predetermined period until the pressure sensed by the transducer exceeds the desired tyre pressure whereupon in succeeding cycles the exhaust valve is opened for a predetermined period until substantial equality of the sensed and desired pressures is achieved.
Claim 15
Dependent Claim
39 words
A system according to claim 13 wherein each opening of the exhaust valve is arranged to result in a smaller pressure change in the tyre than that pressure change which results from each opening of the air inlet valve.
Claim 16
Dependent Claim
56 words
A system according to claim 12 or 13 Therein, in response to a comparator output during a deflation cycle indicative that the tyre pressure is within a predetermined amount of the desired pressure, logic means cooperates with the time control means to reduce the period in each cycle during which the air exhaust valve is opened.
Claim 17
Independent Claim
63 words
A system according to any of claims 10 to 15 including means responsive to the magnitude of the pressure increment occurring between successive inflation cycles for adjusting the open time of the air inlet valve in each cycle so as to obtain a substantially constant, predetermined pressure increment during each cycle at least for a first part oi' the inflation of the tyre.
Claim 18
Independent Claim
76 words
A system according to any of claims 13 to 15 including logic means responsive to the magnitude of said desired pressure for determining the open time of the exhaust valve in each deflation cycle such that, regardless of the magnitude of the desired pressure, a substantially constant, predetermined pressure decrement will be obtained by each opening of the exhaust valve at least for a first part of the deflation of the tyre towards the desired pressure.
Claim 19
Independent Claim
73 words
A system according to any of claims 10 to 17 including a desired pressure selection unit operable manually by a user for selecting a desired pressure to which a tyre should be inflated, means responsive to said pressure selection unit for holding a representation of the selected desired pressure in the system and for providing corresponding signals to said comparator means, and display means for displaying a visible indication of the selected pressure.
Claim 20
Independent Claim
32 words
A system according to any one of the preceding claims including compensating means for compensating for any tendency of the operating characteristics of the transducer and/or the converter means to demonstrate instability.
Claim 21
Independent Claim
35 words
A system according to any one of the preceding claims wherein said time control means comprises time division means arranged to operate upon the local a.c. mains supply frequency for deriving the requisite timing periods.
Claim 22
Dependent Claim
325 words
A tyre inflation apparatus comprising:- an entry facility operable manually for recording in the apparatus a desired tyre pressure to which in use of the apparatus a tyre is to be inflated, said facility being arranged to provide output signals representative of a desired pressure entry; an air pressure transducer arranged so as to be capable of being Exposed to the air pressure of a tyre when the apparatus is being used for inflating the said tyre, the transducer providing an output signal proportional to the incident air pressure; converter means coupled to the output of the transducer for generating a periodic output signal at a frequency which is a function of the transducer output; a counter coupled To the output of the converter means and arranged for counting excursions of said periodic signal; comparator means arranged so as to be responsive to the count held in the counter and to the output signals from the desired pressure entry facility for providing an indication as to the relationship between the tyre pressure, as sensed by the transducer and translated by means of the converter means into a corres- pcnding count held in the counter, and the desired tyre pressure; valve means arranged to be responsive to the indication provided by the comparator means for determining the inflation of the tyre from a compressed air supply; indicator means for providing an indication to a user when the comparator means senses that the pressure within the tyre is the desired tyre pressure; and timing control means controlling the operations of the counter means and the comparator means such that, in operation of the apparatus, a cyclic timing sequence is established during each cycle whereof the output of the converter means is gated into the counter for a first predetermined time period and during a second predetermined time period said valve means is controlled in dependence upon the count accumulated in the counter during said first time period.
Claim 23
Dependent Claim
325 words
A tyre inflation apparatus comprising:- an entry facility operable manually for recording in the apparatus a desired tyre pressure to which in use of the apparatus a tyre is to be inflated, said facility being arranged to provide output signals representative of a desired pressure entry; an air pressure transducer arranged so as to be capable of being Exposed to the air pressure of a tyre when the apparatus is being used for inflating the said tyre, the transducer providing an output signal proportional to the incident air pressure; converter means coupled to the output of the transducer for generating a periodic output signal at a frequency which is a function of the transducer output; a counter coupled To the output of the converter means and arranged for counting excursions of said periodic signal; comparator means arranged so as to be responsive to the count held in the counter and to the output signals from the desired pressure entry facility for providing an indication as to the relationship between the tyre pressure, as sensed by the transducer and translated by means of the converter means into a corres- pcnding count held in the counter, and the desired tyre pressure; valve means arranged to be responsive to the indication provided by the comparator means for determining the inflation of the tyre from a compressed air supply; indicator means for providing an indication to a user when the comparator means senses that the pressure within the tyre is the desired tyre pressure; and timing control means controlling the operations of the counter means and the comparator means such that, in operation of the apparatus, a cyclic timing sequence is established during each cycle whereof the output of the converter means is gated into the counter for a first predetermined time period and during a second predetermined time period said valve means is controlled in dependence upon the count accumulated in the counter during said first time period.
References Cited (Backward Citations)
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