SYSTEM FOR INFLATING TYRES

Abstract: System for inflating tyres comprised of a pressure air supply apparatus with a series of push-buttons (2) for different pressures and completed with a series of collars (6) which may be mounted on the outside of the valve of the tyre with identification on characteristics which match those of one of the push-buttons. The pressure air supply apparatus includes a control unit (12) which acts on a pressure inlet electrovalve (93) or on a pressure discharge electro-valve (95), said control unit (12) having an amplifier (14), a transducer (13), a converter (15) and a zero adjusting circuit formed by to potentiometers (16). Two air supply hoses (9) are each fitted at their ends with a mouthpiece (10) terminated by clamping elements which tend to move towards one of the inclined grooves (20) through the action of a pushing element (22) biased by a spring (23).

Description: The present description relates to a system for inflating tyres, which presents a series of important advantages over the means that are presently used for this purpose. At present, the supply of air pressure to a tyre is carried out by means of an apparatus which incorporates a hose having at its end a mouthpiece, a pressure indicator and a manually activated valve which permits to introduce pressurized air in the tyre until the pressure indicator reaches the required pressure for the type of vehicle. There also exists another type of apparatus for supplying pressurized air which have two push-buttons and a display in which the operating pressure can be observed, said pressure being changeable to reach a determinated pressure by means of one of the push-buttons which permits the increase of the pressure visualized on the display, or by means of the other push-button when it is desired to obtain a lower pressure. In using any of the two systems it is necessary to know prior to the operation the pressure to which the tyre should be inflated since said pressure varies depending on the vehicle to which the wheel is applied and the position of the latter in the front train or the rear train of the vehicle. For this reason, before starting the tyre inflating process, it would be necessary to look into tables in which the pressures of tyres depending on the model of the vehicle are listed. Looking into said tables would cause, in the first place, loss of time and in the second place present a relative effectiveness since there exist vehicle models which do not appear on the list, and also when on a vehicle there are mounted tyres which are different from the original ones supplied by the manufacturer. Another drawback of known systems, and in to a higher degree the first mentioned system is that the pressure supplied to the tyre is not exact, but approximate due to the circumstances of the reading such as inclination of the pressure indicator which gives rise to an erroneous projection of the needle over the scale or similar circumstances. It should be borne in mind that all these circumstances complicate considerably the inflating process of the wheels, since it is an operation which is carried out in very large intervals of time which results in that a very high percentage of vehicles would not contain the adequate pressure for their tyres causing the consequent problems of excessive wearing off of the tyres, a higher risk of accident and a higher consumption in the vehicle, and said inflating process can become even more difficult when the mouthpiece provided at the end of the hose of the air supplying apparatus presents a complex activating device which makes the fixing of the mouthpiece on the valve difficult, even when the valve is in an accesible place; since there exist vehicle models in which the valve is situated inside a cavity arranged in the hubcaps for which the conventional mouthpieces do not reach for connection with the valve without taking off the hubcaps. An automatic inflator is known from FR-A-2 592 972 which is capable of inflating or deflating pneumatic tyres to a prefixed pressure set-point value. Said automatic inflator comprises a command panel with means for introducing said prefixed set-point values, electro-pneumatic means for inflating and deflating tyres or measuring the pressure therein, display means adapted to display tyre pressure values or to indicate instructions for operation by means of luminous indicators and at least one hose for supplying air to the tyre. According to this document, the user introduces the pressure set-point values through a keyboard or by other means such as magnetic cards or magnetic keys. The automatic inflator uses a logic of calculation which compares a measured pressure value in the tyre with the prefixed set-point value introduced in the automatic inflator, calculates an inflating/deflating interval and commands the electro-pneumatic means to inflate/deflate the tyre. This operation is repeated producing successive approximations to the desired set-point pressure value according to a linear extrapolation rule. FR-A- 2 592 972 however, does not disclose the use of means with identifying characteristics corresponding to predetermined pressure values. Due to all these reasons, the inflating process of tyres is extremly cumbersome, and it is an object of the present invention to simplify the known systems. The object is achieved by the subject-matter of claim 1; further advantageous features are defined in the dependent claims. Thus a system is proposed, which is composed of a pressurized air supply apparatus which incorporates a plurality of push-buttons with pre-determined pressure values which cover a very wide range of pressure values employed for inflating tyres; said pressure air supply apparatus presenting two outlet hoses which are fitted with two fast coupling mouthpieces, apt to be fixed on two wheels corresponding to the same train or axis of the vehicle; said two hoses being connected to each other and with the apparatus in such a manner that the pressure supplied by each one is identical which assures that the two wheels of the same train or axis have identical pressures. With the purpose of making the pressure supplied by the hoses to correspond to the pressure indicated by any of the push-buttons previously pushed, the apparatus incorporates a transducer which receives the pressure of the outlet hoses, said transducer producing a differential tension, depending on the received pressure, which is amplified and applied to one of the inputs of an analog-digital convertor circuit in order to subsequently send the digitalized information of the pressure existing in the hoses to a control unit which carries out a comparison of said measurement with that of the pressure corresponding to the push-button previously selected, acting, as a function of the data obtained in said comparison, upon an electrovalve which permits the supply of pressurized air to the hoses or upon an electrovalve which permits the discharge of the pressure of the same; this control unit carries out successive comparisons and the corresponding actuations on one or the other electrovalve in order to bring the pressure supplied by the hoses close to the pressure pre-determined by the push-button until said pressure coincides. The control unit additionally comprises a zero adjusting circuit formed by two potentiometers. Due to the problems inherrent with mouthpieces presently used in this type of apparatus, mouthpieces for fast coupling over the valve are provided in order to be mounted at the end of the hoses, which have closing means when they are not connected to the corrresponding valve in such a form that if the inflating of only one of the tyres is desired, only one hose is used while the other remains closed, thus the adjustment of the pressure of the tyre becoming possible with the pressure selected through the push-button, and because if the automatic closing mouthpieces are not included, one of the hoses would remain open thus the air supply apparatus cannot perform the compensation between the two hoses since one of the two is open thus giving rise to total deflating of the tyre the pressure of which is intended to be adjusted. In order to make possible the rapid and easy connection and disconnection of the mothpiece placed at the ends of the hoses to the valve of the vehicle, either when the latter is outside of the hubcaps or when it is placed in a cavity defined therein, said mouthpiece is arranged to define a cylindrical configuration of reduced diameter and sufficient length in order to reach the valve in the case where the latter is located in a cavity, presenting inside the same closing means composed of a valve core which maintains the mouthpiece closed as long as the latter is not connected to the valve, and rapid connection means which permit the mouthpiece engage onto the valve only by pressing the mouthpiece over the same, incorporating at the exterior thereof a sleeve which when driven towards the rear zone of the mouthpiece releases the latter. In order to eliminate the loss of time which is caused by consulting tables for finding out the pressure corresponding to the vehicle of the user, the system is complementarily equipped with a series of tubular collars, preferably of plastic material, each of which defining their own identifier characteristics which permit the correspondence of each of these characteristics with a determined pressure; each of the push-buttons of the air supply apparatus being provided with an indication of the pressure corresponding to each one and the identifier characteristics corresponding to each pressure, which permits that once a collar with characteristics representing the corrresponding pressure is positioned on the valve of a tyre, the user would not have to consult any tables, but it will be sufficient for supplying the exact pressure to said tyre, to connect the mouthpiece of the air supply apparatus to the valve of the tyre and to activate the push-button which shows the identifying characteristics presented by the collar fixed to the valve of the tyre. Said tubular collar preferably defines on its interior surface at least one rib which permit to fix the same on the valve of the tyre, the fixing of said collar being performed by pressing the same onto the valve body; thus making it very difficult to remove the collar without causing its destruction. In order to understand better the object of the present invention, a preferred practical embodiment of the same is represented in the annexed drawings. In said drawings: Figure 1 shows a pressurized air supply apparatus. Figure 2 shows an elevation view of an identifiable collar (partly cross-sectioned) mounted on a valve of a tyre. Figure 3 shows a partly cross-sectional elevation view of a mouthpiece located at an air outlet of a hose. Figure 4 is a schematic view of the elements involved in the adjustment of pressure by means of preselection of a key corresponding to a pre-determined pressure. As it can be observed in the referenced figures, the system object of the present invention incorporates an apparatus (1) for supplying pressurized air on which a plurality of push-buttons (2) are arranged, each of which presenting differentiating characteristics with resepct to the rest, be it by means of a scale of colors, codes, forms, etc, each of which in relation to control means which permit the adjustment of the pressure supplied by the apparatus to that indicated on the manually activated push-button. On the apparatus (1) there is a digital display (4) in which the supplied air pressure is visualized by means of successive measurements of the apparatus during the inflating process of the tyre. Additionally, the pressure air supply apparatus has two push-buttons (5) which permit the change of the pressure in use in a gradual manner, increasing progressively by activating one of the push-buttons (5) and decreasing progressively by activating the other push-button (5); these push-buttons (5) permit to vary the fixed pressures selected by means of push-buttons (2). In order to facilitate the selectiion of push-button (2) and consequently the air pressure supplied by apparatus (1), the system is provided with a complementary collar (6), preferably tubular and made of plastic material which defines adequate dimensions in order to be fitted onto the body of the valve (7) of tyres. Due to the fact that the threaded ends (7') of the valves (7) have a standard diameter which emerges from a portion of higher diameter, in order to prevent the collar (6) from being easily removed after having been fitted onto the body (7'') of said valve (7), the collar has at its inner zone at least one rib (61) equipped with an inclination such that it permits the fitting of collar (6) by pressure on the portion of the valve (7) which presents a higher diameter the body (7'') thereof which makes difficult its removal because of interlocking of rib (61) over said portion. Additionally an adhesive layer protected by a disposable sheet may be provided at the inner surface of the collar. In a preferred embodiment valve (7) incorporates a threaded cap (8) apt for being fixed at the threaded end (7') of the valve (7), covering the opening of the same and having an extension (81) on the periphery having sufficient length so as to cover the collar (6) when placed on the valve. In order to facilitate a rapid selection of the appropriate push-button (2) for the necessary pressure for inflating the tyre, the collar (6) should present identifying characteristics which are analogous to those of one of the push-buttons (2), be it by means of a scale of colors, an identifying code, a code of forms, etc. in such a way that once the supplying pressure onto the tyre is known, a collar (6) with the corresponding identifying characterisitics of the push-button (2) is locked onto valve (7) of said tyre assisting to supply the adequate pressure to said tyre. In order to limit the penetration of collar (6) onto the body (7'') of the valves, the former (6) incorporates at one of the ends thereof an interior edge (62) which makes frontal contact with the step-shaped portion of the valve defined by the threaded end portion thereof and the adjacent body portion (7'') with higher diameter. The apparatus (1) may include one or two hoses (9) for the outlet of the pressurized air which are fitted with a mouthpiece (10) which is intended to provide the connection of the hose (9) to valve (7) of the tyre. In the case where the apparatus (1) incorporates two hoses (9) as presented in figure (4), said hoses should be joined with each other as well as with a pneumatic circuit in which there is a branch (91) for the entry of pressurized medium into hoses (9) where there is an anti-return valve (92) and an electro-valve (93) are inserted therein, said branch (91) for the entry of pressure being connected to a compressor (11); the other branch (94) of the pneumatic circuit includes an electro-valve (95) which when activated permits the discharge of the pressure of the hoses (9). Said electro-valves (93) and (95) may be activated directly through push-buttons (5) of manual activation or through a control unit (12). The pressure existing inside the hoses (9) is measured by means of a transducer (13) and the signal generated by the latter (13) is amplified by means of amplifier (14), said amplified signal passing thereafter through an analog-digital converter (15), the digitalized measurement is then received by the control unit (12) which is connected to push-buttons (2) which permit the direct selection of a pre-determined pressure. Said control unit (12) carries out a comparison between the pressure measured by the transducer (13) and the pressure corresponding to the selected push-button (2), acting depending on the data obtained from said comparison, on electro-valve (95) in order to permit a partial discharge of the pressure of said hoses (9). Once the mouthpieces (10) are connected to the valves of tyres, the control unit (12) performs a first comparison between the pressure selected by means of one of the push-buttons (2) and the pressure existing in the tyres, acting subsequently on electro-valve (93) or (95), repeating successively various comparisons and the corresponding actions on electro-valves (93) and (95) until the measured pressure is approached, within a pre-established margin of error, to the pressure selected by means of activating one of the push-buttons (2), said control unit (12) incorporating a zero adjusting circuit fromed by two potentiometers (16). In the case where it is desried to carry out the inflating of the two tyres of the same axis or train of the vehicle, to a determined pressure, the two hoses (9) should be connected onto the same, the system thus carrying out the inflating to a pre-established pressure and the adjusting of the two tyres to said pressure since the two hoses (9) are joined to each other. In order to facilitate the connection of the mouthpieces (10) to the corresponding valves (7), it is provided that the formers (10) define a substantially cylindrical shape inside which there are automatic locking means (17, 20, 21) which have a pushing rod (17) at their end to lift a valve stem (not shown) of the valve when the mouthpiece is connected to the valve (7) and impede the outflow of the pressure when the mouthpiece (10) is not connected to the valve (7). The central cylindrical portion (18) in which said locking means (17, 20, 21) are placed presents inside and around the rod (17) a toric joint (19) which terminates at a step-shaped end with the purpose of locating the end of the valve (7) inside the body (18), the former (7) would act both with its front end and with its sides on the toric joint (19) impeding the outflow of air due a slight misalignment of valve (7) with respect to the central body (18). This cylindrical body (18) presents at its front end two inclinated grooves (20) in which two bars (21) are located which have the function of fixing the mouthpiece (10) onto valve (7), said bars (21) tending to be displaced towards the front zone of grooves (20) due to the action of a pushing element (22) which is pressed on its rear area by means of a spring (23). With this arrangement, by pressing axially the mouthpiece (10) on the valve (7), the end of the latter displaces the bars (21) towards the rear zone of the grooves (20) overcoming the pressure exerted by spring (23) until the front end of the valve (7) meets with the step-shaped portion defined by the toric joint (19), thus both elements remaining immobilized due to the pressure which bars (21) exert on the threaded zone (7') of valve (7). Over the pushing element (22), an exterior sleeve (25) is arranged the movement of which towards the front zone is limited by a circular clip (26) in such a manner that having connected the mouthpiece (10) to the valve (7) due to the pressure exerted towards the front side by bars (21), the mouthpiece (10) can be released from valve (7) practically in an instantaneous manner. Having sufficiently described the natur of the present invention as well as one way of putting it into practice, it only remains to be added that it is possible to introduce changes in form, material and disposition in the invention as a whole or in parts of which it is composed of as long as such changes do not vary substantially the characterisitics of the invention which are claimed as follows:

Claims: System for inflating tyres, of the type comprising a pressurized air supply apparatus (1) adapted to inflate pneumatic tyres to a prefixed pressure value, the apparatus (1) having a control unit (12) for comparing a measured pressure value of the tyre with the prefixed pressure value and acting upon an associated pneumatic circuit, display means (4) for displaying the measured values and at least one hose (9) for supplying said pressurized air to a valve (7) of the tyre, characterized in that said air supply apparatus (1) incorporates a series of push-buttons (2) each of which corresponding to a predetermined pressure and having its own identifying characteristics; the system being completed with a series of substantially tubular collars (6) preferably made of plastic each of which having a dimension which is adequate for being mounted externally onto a body (7'') of the valve (7) of the tyre and having inside at least one rib (61) which permits immobilizing the collar (6) on the body (7'') of the valve (7) when mounted by pressing it thereon; whereby the collar (6) to be mounted on the body (7'') of the valve (7) of a specific tyre presents identifying characteristics which correspond to those of the push-buttons (2) provided for the supply of the pressure adequate for the specific tyre. System, according to previous claim, characterized in that the control unit (12) of the pressurized air supply apparatus (1) carries out successive comparisons between the pressure selected by means of activating one of the push-buttons (2) and the pressure measured in the outlet hoses (9) by means of a transducer (13), in order to act, depending on the comparison carried out, upon an electro-valve (93) for the inlet of pressure medium or an electro-valve (95) for discharge of pressure, with the purpose of equalizing the pressure supplied through the hoses (9) with the selected pressure; the apparatus (1) incorporating an amplifier (14) for the signal of the transducer (13), an analog-digital converter (15) and a zero adjusting circuit formed by two potentiometers (16). System, according to previous claims, characterized in that the air supply apparatus (1) has two outlet hoses (9) which are connected between each other and onto the tyres of the same train of a vehicle by means of two mouthpieces (10) of cylindrical shape which internally incorporate conventional locking means (17,20,21) and have elements at the front end for grasping on the valve (7) which tend to move towards the front zone of two inclined grooves (20) due to the action of a pushing element (22) pressed by a spring (23) over which there is mounted a sleeve (25) externally which can be displaced axially in order to release the mouthpiece (10) from the corresponding valve (7). System, according to previous claims, characterized in that the collar (6) has inside and at one of the ends thereof a peripheral edge (62) which acts as a limit stop when pressed on the body (7'') of the valve (7), said edge (62) abutting on a step-shaped portion defined by body portion (7'') with higher diameter adjacent the threaded end portion of the valve (7). System, according to previous claims, characterized in that the rib (61) enclaving the collar (6) on the valve (7) of the tyre is composed of at least one inclined flange arranged at the inside surface of the collar (6).

Inventors: LOUREIRO BENIMELI FERMIN-JAIME, LOUREIRO BENIMELI, FERMIN-JAIME
Applicants: FAST AIR SL, FAST AIR, S.L.
Application year: 1993
Main classification: B60S5
IPC codes: B60S5, G05D16