DEVICE FOR THE PUMPING OF PNEUMATIC TIRES, ESPECIALLY LARGE TIRES

Abstract: Pressurized air for the pumping of a truck tire is lead through a control device comprising a contact manometer (4), an output pumping hose (10), a pair of switching solenoid valve means (16 and 18) and an electric control unit (20) which by means of a repetition rate source means (26) influences upon one of the valve means (16) to successively switching of the lead-out (8) unto the pumping hose (10) between establishing of a connection with a lead-in for pressurized air (6) and with the manometer (4) respectively in such a manner that the manometer reaches to indicate the actual pressure within the tire between the pumping periods wherein the supply of pressurized air is fully opened. A maximum value contact (24) of the manometer serves to switch the first valve means (16) permanently to the manometer connecting condition when a certain overpressure within the tire is attained and to activate the other valve means (18) to successively switching of the lead-out to the pumping hose (8) between establishing of connection respectively with a venting-opening (30) and the manometer (4). An operational pressure contact (22) of the manometer is applied to establish switch-off of the venting when the pressure within the tire is relieved to the wanted operational pressure. The device is in an all automatic manner able to perform a fast and reliable pumping of the tire also when prescribed that pumping shall take place in a manner establishing a certain overpressure and thereafter venting the pressure until the operational pressure within the tire is attained. .

Description: 1 Device for the pumping of pneumatic tires, especially large tires. The present invention concerns a device for the pumping of pneumatic tires, especially large tires. Generally, it is prescribed that truck tires, which f.i. have to be pumped to an internal pressure of 5 kgs (here using the expression of general speaking, technically implying an over-pressure of 5 kgs (equal to roughly 50 newtons per square cm) against the surrounding atmospheric pressure), by reason of security at first have to be pumped to a pressure of 8 kgs after which the pressure is relieved to the attainment of an operational pressure of 5 kgs. The pumping process lasts several minutes, and it belongs to the state of the art to control the pumping process by means of a pressure regulating means in shape of a spring loaded valve arranged to perform more and more closing-off for the pressurized air supply when the counter pressure is being augmented from the tire for which purpose the valve is struc¬ tured adjustable to be able to establish a complete shut-off when attaining the aforementioned f.i. 8 kgs. The valve is connected with a manometer, enabling the operator to watch when the pumping is terminated, and the operator can hereupon shut-off for the pressurized air supply and can manually hold a venting-valve operated untill relief of the pressure of the tire has taken place by reaching of the 5 kgs pres¬ sure within the tire. The purpose of the present invention is to present a device which by means of an improved and fully automatical manner of operation is able to be used for the control of such a pumping processs. A device constructed according to the present invention is mainly characterized through the features mentioned within the characterizing part of claim 1. The device excels as it is able to carry out the pumping process within a short span of time because the device is able to work by means of a full opening up for the pressurized air supply with the exception of the short time periods with shut-offs during which periods on the other side such a condition of OMPI ^&*WT10 pressure equilibrium between the pressures being present within the tire and within the manometer is going to be . attained that the manometer becomes capable of successive indications of the factual, obtained pressures within the tire during the pumping process. On the other hand, by means of its manometer the device according to the state of the art does not indicate the existing pressure within the tire before the timely elapse of the final phase of the pumping process because, normally, the external pressure of the air supply is larger than the pressure existing within the tire which is due to the constricted passage being present at the vicinity or within the air lead-in of the tire and also is due to possible presence of oscillating variations which are produces due to the operational functioning process of the pressure regulating means. On the other side, it has to be regarded as essential that the operator now is able to supervise the pumping process by watching true values of the intervening pressures, obtainment being reached thereby that during the pumping process the said repetition rate source member produces periodical shut-offs of the pressurized air supply using shut-offs of short durations. In spite of these shut-offs the pumping process taking place to attain the said maximum value works essentially faster than the pumping obtained by the application of the control device construc- ted according to the state of the art. Furthermore, the subsequent venting-operation to attain operational pressure is produced fully automatically by means of the same, afore¬ mentioned, repetition rate source member if a suitable venting-valve being itself of simple structure is comprised by the switching valve means. During the venting-opeation the performed intermittent operation of the valve means assures that a correct reading of the manometer pressure can take place and that, based upon the operational condition of at least one, practically correct, indicating manometer, an automatically produced halt of the venting-operation can be performed. OMPI The present invention is now further explained in details under reference to the drawing which schematically serves as an illustration illustrating two different execu¬ tions of the device according to the invention and being shown in Fig. 1 and Fig. 2. The device shown in Fig. 1 of the drawing is contained within a box or housing 2 comprising an easily readable mano¬ meter 4, lead-in stud 6 for pressurized air supply and a lead-out stud 8 which by means of a hose 10 for pressurized air is connectable to a truck tire 12 which has to be pumped with air being passed via a fitting means 14 of generally known structure; from the fitting means 14 an internally comprised valve cone member mostly is taken out with the purpose of obtaining a faster pumping, and this valve cone member is easily refittable after the pumping process without introducing any essential loss of pressure thereby within the tire. The device comprises two solenoid switching valves 16 and 18 and an electric control unit 20 being connected in part with the solenoid valves and in part with the manometer 4 which manometer is of the contact manometer type compri¬ sing two adjustable contact elements 22 and 24. In addition, the control unit 20 comprises or stays in connection with a repetition rate source member 26. Each of the solenoid valves comprises a basic stud B which in concern of valve 18 is connected with the lead-out stud 8 and each valve comprises two valve studs I and II respectively II and IV which by means of the switching operations of the valves can be connected with the respective tive basic studs B. The basic stud B belonging "-ire the valve 16 is connected to valve stud III of valve 18 the valve stud III being connected to the manometer 4 via a tube 28 and the stud IV is either open or is connected to a venting-stud 30. The stud β for pressurized air is connected to the valve stud I, and with the device not in use the valve 16 occupies that position in which the basic stud B is connected to the valve stud II (in the following description designa¬ ted position II), i.e. occupying a closing position for the presurized air supply lead-in being present on stud I. The function of the device is initiated by means of a not shown activating button or the like, by means of which the valve 16 is brought to occupy position I while valve 13 is brought to occupy or already occupies the position III. By means of the repetition rate source member 26 the valves are kept occupying these positions, during f.i. 10 seconds, whereafter presurized air passes unto the tire 12, subse¬ quently the repetition rate source member 26 causes a switching operation of the valve 16 to occupy its position II for a time period of 2 to 3 seconds. During this short period of time, where the pressurized air supply is shut-off, an equalizing of the pressures takesplace within the space now being shut-off and which space consists of the tire 12, the hose 10, the communicating valve passages and the mano¬ meter tube 28 so that the manometer at the end of this i r>. period of time is going to indicate the factual pressure existing within the hose. Subsequently switching-over to a filling period of 10 seconds and a measuring period of 2 to 3 seconds takes place, and so on. On the drawing the manome¬ ter needle or pointer points to an intervening value, i.e. corresponding to an intervening phase during the filling operation. ' The tire has to be pumped to the attainment of a maxi¬ mum pressure value given by the position of the contact element 24 of the manometer. Before this, the manometer needle or pointer has to pass the contact element 22 repre- senting the final operational pressure within the tire, but the control unit 20 is constructed not to respond upon the activation of the contact element 22 during passing of the needle or pointer in upwards direction. When the tire by means of this intermittent pumping process has attained the wanted maximum pressure the manome¬ ter via the contact element 24 signalises this and the con- OMPI trol unit 20 performs a switching of valve 26 to a permanent occupation of position II whereas the valve 18 during the complete filling operation permanently has occupied position III. Hereupon the control unit 20 now causes a switching of the valve 18 by means of the repetition rate source member to occupy position IV, during f.i. 10 seconds, producing a venting-operation of the tire by means of venting-stud 30. After this a switching of valve 18 to occupy position III, during f.i. 2 to 3 seconds, is performed whereby the manome¬ ter 4 is brought to be able to adapt itself to indicate the factual, now somewhat lower pressure within the tire. After this follows anew a venting-phase and a measuring-phase, and so on, untill the manometer is brought to activation of the contact element 22 during a movement downwards of the needle or pointer. This activation causes a switching operation or a blocking of the valve 18 to occupy or to remain in posi¬ tion III and as a possibility the device can perform a --- , sound- or light signalisation indicating the termination of the filling operation. By means o£ the manometer the opera¬ tor is able to control that the wanted final pressure is attained after which the operator may remove the pressure hose from the tire and in case of need herefore remounts the valve cone member within the fitting member 14. The complete cycle time required for the device accor¬ ding to the present invention may amount to about 6 minutes whereas solely the pumping process by the use of a device according to the state of the art may last 8 to 9 minutes. The present invention is not limited,to the execution described hereby for the device. Thus, the valve system may be structured otherwise or be built otherwise together to obtain an execution of the mentioned functions, as f.i. by the application of one single switching slide member compri¬ sing a plural of operational positions, also the form of control may be modified within the scope of the present in¬ vention. It is thus possible to establish a working with OMPI filling periods of decaying durations, or the passage of the contact element 22 by the manometer needle or pointer during the pumping operation may be used to perform a switching of the repetition rate source member 26 so that filling peribds bf shorter durations are obtained during the remaining part of the pumping process. Especially if the last filling periods hereby become short the activation of the contact element 24 does not have to be used to perform a direct shut-off of the pressurized air supply but can be used sole- ly to per oral a preparation of the control unit 20 for the fact that the already initiated illing period has to be the last. Attainment of final pressure can be governed or con¬ trolled from the contact element 22 in a similar manner. The manometer may be realised as an electronic digital instru- ent; even though it may be acceptable to renounce upon a manometer reading as thus, it remains essential that filling and venting take place in an intermittent manner._ Fig. 2 of the drawing illustrates a modified execution of the device where switching valves 16 and 18 are replaced by three separate solenoid valves, to be understood as seat valves of high reliability of functibning to perform opening and closing operations. In Fig. 2 these valves are referred to with numerals 32, 34 and 36 whereas the other reference numerals remain unchanged. 32 designates a supply valve which is opened during the pumping phase during which the the valves 34 and 36 are kept closed. In the measuring phass during the pumping operation valve 34 is opened to give access to the manometer whereas the valves 32 and 36 are closed, to be understood in that way that during the pumping operation the control unit 20 takes care of performing of after each other following openings and closings of the two valves 32 and 34 whereas the valve leading to the venting-opening 30 is kept closed. Respectively during the venting-phase it takes care of performing of after each other following openings and closings of the valves 34 and 36 whereas the supply valve 32 is kept closed. OMPI In Fig. 2 of the drawing furthermore pairs of rotatable knobs 38 and 40 with attached scales are illustrated. These rotatable knobs are connected with potentiometers staying in connection with the repetition rate source member 26 with the purpose of making an adjusting of one or more time inter¬ vals possible. The scales carry indications of sizes of re¬ spectively diameter and width of the tire, i.e. the volume of a particular tire can easily undergo registration or re¬ presentation by a corresponding adjustment of the two rota- table knobs. The potentiometers are comprised within a control circuit of the repetition rate source member 26 in such a manner that the durations of at least the pumping intervals are augmented being larger the particular volume is so that the device in a simple way lend itself to an optimisation to tires comprising a very large range of sizes so that the pumping operation can take place by the quickest possible way maintaining the necessary measure of security. By means of the knobs for volumes 38, 40 further¬ more the durations of the venting-intervals automatically can be made longer the larger the tire volume is. Normally, no reason may be present to perform any change of the opening time being present for the manometer valve 34. It has to be mentioned, that that essential advantage of security is attained by means of the present invention that it no longer is required that the operator has to do work with the tire when the tire presents itself as being pumped with air with maximum of pressure in the tire, works as taking away of the pressure hose and remounting of the valve cone member, these works first have to be carried out when the pressure within the tire is relieved to the opera¬ tional pressure value. When maximum pressure was present these works had earlier to be carried out whereby a certain risk for phenomenas of explosions were present as well in the tire itself as especially in the holding means for the tire. OMPI ^LsZ

Claims: C L A I M S 1. Device for the pumping of pneumatic tires comprising a pressure regulating means inserted in a line conducting pressurized air c h a r a c t e r i z e d i n t h a t the device comprises switching valve means (16, 18) and repetition rate source means (26) for the switching of the said valve means (16, 18) and pressure registrating means, preferably in form of a contact manometer (4), which parts are connected in respectively the pressure air system and in a control system in such a way that intermittent the switching valve means (16) are switched between a condition implying full opening for the pressurized air and a condi¬ tion implying full shut-off hereof in short time periods which though have sufficient duration to attainment of a pressure equalisation within the closed space with air being connected with the tire (12) so that the manometer (4) is able to adapt itself to indicate the correct pressure before reopening for'the pressurized air as the pressure registra¬ ting means (4, 24) are fitted to a switch-off of this control functioning when the pressure has been augmented to attainment of the wanted maximum value and are fitted to establish an intermittent switching of the switching valve means (18) during a maintained shut-off of the supply of pressurized air between a condition of closing-off and a condition of venting (IV) untill when the wanted operational pressure is attained a halt of the relieving of the pressure is established by the pressure registrating means (4, 22). 2. Device according to claim 1 c h a r a c t e ¬ r i z e d i n t h a t the said valve means comprise two switching valve means (lβ and 18) of which the one (18) is able to connect a tire pumping line (10) respectively to a venting-opening (30) and to a stud (III) being permanently connected to a stud (B) on the other valve means (16) where¬ by this valve means is fitted to connect the respective stud (16B) with respectively the manometer (4) and a lead-in for pressurized air (6). 3. Device according to claim 1 c h a r a c t e ¬ r i z e d i n t h a t the switching valve means com¬ prise three shut-off valve means, preferably solenoid acti- vated seat valve means, being positioned respectively in the air lead-in (6, 32), in the lead to the manometer (4, 34) and in the venting-line (30, 36) whereby the three valve means lead to a common space or tube from which the pumping line (8) is ramified and the three valve means are being switched by means of a control unit. 4. Device according to claim l or 2 c h a r a c t e ¬ r i z e d i n t h a t the device comprises selecting means (38, 40) adapted for receiving read-ins of the size of the volume of the tire to be pumped and which selecting means are control connected with the control system (26, 20) in such a way that the durationsof the pumping intervals and possibly also the durations of the venting-intervals are *a£_5. ■ longer or lesser of duration all depending upon the size of the tire volume. OMPI

Inventors: HJORTH HANSEN ARNE
Applicants: HJORTH HANSEN ARNE
Application year: 1982
Main classification: B60C23
IPC codes: B60C23, B60S5, G01L17