US3283775A

US3283775A - Inflating apparatus

Info

Publication number: US3283775A
Application number: US265557A
Authority: US
Inventors: Donald L Spender
Original assignee: Scovill Inc
Current assignee: Scovill Inc
Priority date: 1963-03-15
Filing date: 1963-03-15
Publication date: 1966-11-08
Anticipated expiration: 1983-11-08

Description

Nov. 8, 1966 D. sFr-:NBER

INFLATING APPARATUS Filed March l5, 1965 United States Patent Oilce 3,283,775 Patented Nov. 8, 1966 3,283,775 INFLATING APPARATUS Donald L. Spender, Cheshire, Conn., assigner to Scovill Manufacturing Company, Waterbury, Conn., a corporation of Connecticut Filed Mar. 15, 1963, Ser. No. 265,557 3 Claims. (Cl. 137-2245) rFhis invention relates to [an inilating apparatus, especially use-ful for t-ire inilating stations and particularly to such a device which is completely automatic in operation.

In general, the object of the invention Vis to provide an inating `apparatus having improved reliability in action and which is comparatively economical to manufacture and rassemble.

Another object is to provide an improved apparatus of the kind described wherein adjustable means, such as a control knob, can be manipulated to adjust the pressure in the delivery line accurately while the .pressure is being indicated on a standard pressure gauge.

More specifically, an object of Jthe invention is to control the cycling of the inlet valve by relatively simple means between the pressureeresponsive devi-ce and the delivery conduit, which means requires no moving parts, such as relays, dash pots or the like.

A still further object is to provide a pressureresponsive -switch which will usually be referred to as a pressure switch for directly controlling the supply of current either to a solenoid inlet valve lfor admitting air to the delivery conduit when the pressure in the tire is too low, or to another solenoid valve 4for exhausting lair from such conduit when the pressure is too high-the operation in either case being automat-ic merely by the application of the air hose to the tire.

In the accompanying drawing, I have shown Ifor purpose of illustration, one embodiment which the invention may 'assume in practice. In the drawing:

FIG. 1 is a diagrammatic view of one embodiment of my improved inflating apparatus; and,

FIG. 2 is also a `diagrammatic View of a portion of the 'apparatus with t-he elements in position tor exhausting air.

The apparatus shown in the drawing includes a supply of compressed air, such as a reservoir which is connected tothe delivery conduit through -a solenoid-operated inlet valve 11. The delivery conduit as shown, includes .a pipe 12 `and a flexible air hose 13.

The solenoid inlet valve 11 is preferably of the type which opens when energized and closes when deenengized. Power for the solenoid is supplied from

power lines

14 and 15 under the control of a pressure switch, generally designated PS. The switch PS includes a movable springy contact leve-r 16 which is mounted in a block 17 of insulating material and normally tensioned against an upper contact 18. There is also a lower xed contact 19 normally spaced from the spring lever 16, and the

contacts

18 and 19 lare also mounted in the block 17.

For actuating the switch lever 16, there is employed a pressure-responsive actuator of the general type discl-osed in the patent to Williams 3,045,704, which comprises a hollow chamber or cylinder 20, a block of closed cell foam material 21, such as foam rubber or foam plastic, secured 'as by adhesive at its llower end to the inner surface of the chamber and having a movable actuator pin 22 extending downwardly through Aa hole 23 in the foam material. Pin 22 is carried by a disc 24 secured t-o the upper end of the foam material 21 as by adhesive. Thus, on low pressure, the -actuating pin 22 withdraws into the chamber and on increase of pressure, the loam material contracts lengthwise to project the pin 22 downwardly -iirom the chamber.

' dimensions.

Provision is made for adjusting the block 17 carrying the switch cont-

acts

16, 18 and 19 relative to the pressureresponsive unit `or actuator pin 22. For this purpose, the block 17 is attached to a movable arm 25 having a ilanged base 25a which can slide in a suitable Iguideway 26 in a stationary support bracket 27. The bracket 27 has a pair of laterally extending arms 28 `and 29 in which is journaled an adjusting screw 30 having threaded engagement with the arm 25 Ifor movin-g the same. The upper end of the screw 30 is provided with a suitable knob 30a for adjusting purposes. The upper arm 28 may be further extended to provide la platform 28a for supporting the hollow chamber 20 of the pressure-responsive actuator. As shown, this platform may actually form the bottom wal-l of such chamber.

The hollow chamber 20 is in communication with the delivery conduit through a connecting line which includes a flow restrictor 31 yand a reservoir 32 between the ow restrictor 31 and the chamber 20. The ow rest-rictor may be of any known type and is often referred to as a ow control valve. It may be adjustable vas by means of a screw-threaded valve stem 33. The .reservoir means is of predetermined volumetric -capacity and may be in the form of a cylinder or merely Ia pipe having the desired The combination of the ilow restrictor and :reservoir means retards the surging of air in either direction so that the pressure-responsive actuator does not move suddenly in response to a pres-sure drop or rise. The pressure gauge 34 is connected in the line between the How restrictor 31 and t'he chamber 201.

Means .are also provided for automatically exhausting air from the delivery line when the pressure in the tire is too high. The pressure-responsive actuato-r will respond to such higher pressure and push the movable switch arm 16 downwardly against contact 19. This will cause energization of the solenoid -outlet valve 35 Ifrom power line 14, movable contact lever 16, stationary contact 19, wire 36 through the solenoid and back to power line 15 through wire 37, to cause opening of the valve 35. This valve is connected to the atmosphere by a pipe 38 in which there is preferably connected a flow restrictor valve 39 which may be similar to valve 31.

The operation and manner of using the device will now be Ireadily understood. The delivery line is normally under the pressure which is desired as t'he maximum Idelivery pressure. This is linitially determined by adjusting the screw 30 and thus the position of the

switch contact elements

16, 18 and 19 relative to the actuating pin 22 of the pressure responsive device. When this is done, the gauge 34 will promptly .indicate the pressure in the delivery line which will be static when the .air is not being delivered. With this condition, the switch arm 16 will be held by the pin 22 in a neutral position -as indicated in dotted lines in FIG. l.

Now assuming the delivery hose 13 -is .applied to an .under-inflated tire, the pressure in the reservoir 32 and chamber 20 will be reduced as air ilows therefrom to the tire, whereupon the -cellular material of the block 21 will expand to lift the actuator pin 22 and close the enen giz-in'g circuit for t-he solenoid valve 11. In this case, current will flow `from power line 14, through the

switch elements

18 and 16, line 40 of the coil of the solenoid, .and back through line 37 to power line 15. The valve 11 then opens allowing high pressure air from tank 10 to ilow directly to the t-i-re, and also to the chamber 20 under the retarding action of the valve 31 land reservoir 32. After a short interval of time, the pressure in chamber 20 will rise to cause the cellular block 21 to contract and project the pin 22 `downwardly enough to break the contact 18, thus causing deenergization -and closing of the inlet valve. If the pressure in the tire is still below the maximum set on the `gauge 34, the pressure in chamber 20 will again be reduced and the cycle repeated until the pressure lin the tire, and thus the delivery line, reaches the desired maximum. `In that event, the actuator pin is holding the movable switch contact away lfrom the stationary contact 18. Everything then is in a state of equilibrium, but if it is desired -to then adjust t-he delivery pressure to a different value, it is only necessary to adjust the screw 30 and Watch the gauge 34.

Now if the pressure in the tire is higher than the desired pressure as reliected by the gauge 34, the pressure will build up in the chamber 20 so that the movable contact 16 closes on the bottom Contact 19. This causes energization of the outlet solenoid valve 35 through the circuit already described land allows the air to be exhausted from the delivery line, reservoir 32 land chamber 20 under the retarding effect of the flow restrictor 39 so as to prevent any quick surges. This cycling action of the valve 35 will continue until the desired pressure is attained when the actuator pin 22 moves to the neutral position to cause closing of the valve 35.

As a result of my invention, it will now be apparent to those skilled in the art that an exceedingly reliable and economical apparatus is provided for inllating tires to the desired pressure. This pressure is easily adjustable by a simple control knob 30a which need not be calibrated, the pressure being merely reliected on a common pressure gauge. The cycling of the supply valve is determined only by the capacity of the reservoir means land the characteristics of the flow restrictor, thus avoiding the use of devices with moving parts which are not only more expensive, but less reliable in operation.

It will also be noted that if desired, only the pressure switch, gauge and reservoir will be required at the air delivery station and that the apparatus containing the solenoid valve can be located at a remote point inside a building.

What I claim is:

1. In an inilating apparatus the combination of (a) .an air delivery conduit adapted for connection toA a tire or the like;

(b) a solenoid inlet valve connecting said conduit to a source of compressed air, and which is open when energized and closed when deenergized;

(c) -a pressure switch connected in circuit with the solenoid valve and constructed and arranged such that current ows directly from the switch to said solenoid valve;

(d) a connecting line between said pressure switch and said delivery conduit so that the pressure switch will respond to pressure changes in said conduit;

(e) means for adjusting said switch whereby a predetermined maximum delivery pressure is maintained in said connecting line; and

(f) means including said switch to automatically cycle the operation of said valve, said last named means controlling the cycling of said inlet valve by retarding the opening action of said pressure switch upon a surge of air into said delivery conduit at a pressure substantially higher than said predetermined delivery pressure, yand also for retarding the reclosing action of said switch on a reduction of pressure in said delivery line, which means consists solely of a flow restrictor in said connecting line (d) and reservoir means of predetermined capacity between said ilow restrictor and said pressure switch;

whereby repeated charges of air may be supplied to said delivery conduit by the controlled cycling of said solenoid inlet valve until said predetermined maximum delivery pressure remains substantially constant in said delivery conduit.

2. In an inliating apparatus the combination defined in claim 1 together with a pressure gauge in said connecting line (d) between said ow restrictor and pressure switch whereby the pressure switch may be adjusted by reference lonly to said gauge to establish the predetermined maximum delivery pressure.

3. In -an inating apparatus the combination dened in claim 1 together with a solenoid outlet valve connected to said delivery conduit, means operated by said pressure switch in response t0 a predetermined high pressure in said delivery conduit for energizing said outlet valve to open the same, and a ow restrictor on the outlet side of said outlet valve for retarding the exhaust of air from said delivery conduit when said outlet valve is open.

References Cited by the Examiner UNITED STATES PATENTS 1,655,003 1/1928 Woodford 137-224.5 1,903,233 3/1933 Gille 137--224.5 2,029,085 1/ 1936 Sussin 137-2245 2,057,889 10/1936 Fagan 137-224 3,045,704 7/1962 Williams 137-505.41 X

WILLIAM F. ODEA, Primary Examiner.

ISADOR WEIL, Examinez'.

D. LAMBERT, Assistant Examiner.

Claims

1. IN AN INFLATING APPARATUS THE COMBINATION OF (A) AN AIR DELIVERY CONDUIT ADAPTED FOR CONNECTION TO A TIRE OR THE LIKE; (B) A SOLENOID INLET VALVE CONNECTING SAID CONDUIT TO A SOURCE OF COMPRESSED AIR, AND WHICH IS OPEN WHEN ENERGIZED AND CLOSED WHEN DEENERGIZED; (C) A PRESSURE SWITCH CONNECTED IN CIRCUIT WITH THE SOLENOID VALVE AND CONSTRUCTED AND ARRANGED SUCH THAT CURRENT FLOWS DIRECTLY FROM THE SWITCH TO SAID SOLENOID VALVE; (D) A CONNECTING LINE BETWEEN SAID PRESSURE SWITCH AND SAID DELIVERY CONDUIT SO THAT THE PRESSURE SWITCH WILL RESPOND TO PRESSURE CHANGES IN SAID CONDUIT; (E) MEANS FOR ADJUSTING SAID SWITCH WHEREBY A PREDETERMINED MAXIMUM DELIVERY PRESSURE IS MAINTAINED IN SAID CONNECTING LINE; AND (F) MEANS INCLUDING SAID SWITCH TO AUTOMATICALLY CYCLE THE OPERATION OF SAID VALVE, SAID LAST NAMED MEANS CONTROLLING THE CYCLING OF SAID INLET VALVE BY RETARDING THE OPENING ACTION OF SAID PRESSURE SWITCH UPON A SURGE OF AIR INTO SAID DELIVERY CONDUIT AT A PRESSURE SUBSTANTIALLY HIGHER THAN SAID PREDETERMINED DELIVERY PRESSURE, AND ALSO FOR RETARDING THE RECLOSING