Wheel pressure management system of a vehicle, vehicle including such management system, related vehicle wheel, related rim, management kit and management procedure

Abstract

The present invention relates to a pressure management system for at least one inflatable tire, comprising : at least one wheel (10) including at least one inflatable tire; - at least one first airtight chamber A; at least a second inflatable chamber B and at least partially defined by said tire, chamber B being airtight and distinct from chamber A; a first communication passage (20) between chamber A and chamber B a second communication passage (25) between chamber B and an environment external to wheel C; a third communication passage (30) between chamber A and external environment C; opening and closing means (40, 140, 240, 240b) configured to alternately open and close said passages to each other.

Description

[0001] Applicant :

[0002] OCHAIN S.R.L. , Via Romagnosi , n. 12 - VARESE (VA) , Italy.

[0003] VAT number 03707500124

[0004] Title: Wheel pressure management system of a vehicle, vehicle including such management system, related vehicle wheel, related rim, management kit and management procedure.

[0005] ★ ★ ★ ★ ★

[0006] DESCRIPTION

[0007] The present invention concerns a vehicle wheel pressure management system, a related vehicle comprising such a system, a related vehicle wheel, a related rim, a management kit, and a management process. The invention is made with reference to inflatable wheels, therefore equipped with a tire. The invention is applicable to any type of vehicle, including cars, trucks, buses, and is particularly appreciable in the field of sports, for example that of bicycles, preferably e-bikes.

[0008] PRIOR ART

[0009] In the bicycle industry, especially mountain bikes, the practice of varying tire pressure according to need or preference is well known.

[0010] For example, lower pressure gives more grip, higher pressure more speed.

[0011] The change in pressure may be desired according to the type of soil, or slope or performance sought. For example, on a technical climb a lower tire pressure is needed, and on a downhill a higher pressure is preferable .

[0012] To date , these changes have to be set manually, for example at the start , and it is unthinkable to make them several times as needed, especially in the case of a race , where they would be most required instead .

[0013] It is also known that tire pressure can change undesirably during use for example due to temperature or punctures or leaks .

[0014] Another desirable management therefore is to maintain a desired constant pressure during use .

[0015] The problems mentioned above are found in all areas af fected by vehicles with inflatable wheels , so also automotive or more generally wheeled transportation, whether for sport or ordinary applications .

[0016] The general purpose of the present invention i s to overcome all or part of the problems of the prior art .

[0017] A preferred purpose of the present invention i s to enable pressure management of a tire during operation of a vehicle .

[0018] An additional preferred purpose is to enable active management of a tire pressure that includes at least one pressure change .

[0019] Another additional preferred purpose is to allow for variation in a tire ' s pressure during use , preferably either increasing or decreasing .

[0020] Another further preferred purpose is to allow management that maintains the pressure of a tire substantially constant during use .

[0021] Another further purpose of the present invention is to enable a user to control the management of the pressure of a tire during use .

[0022] Another additional preferred purpose is to provide a pressure management system applicable to wheel s originally lacking such a system, such as wheels according to pre-existing technologies .

[0023] Another additional preferred purpose is to provide a pressure management system integrated with other electronic management systems of a vehicle .

[0024] Another additional preferred purpose is to provide an electronic pressure management system for a tire .

[0025] Another additional preferred purpose is to provide a pressure management system that is easy and economical to implement .

[0026] Another additional preferred purpose is to provide a pressure management system that is easy and practical to implement .

[0027] GENERAL INTRODUCTION

[0028] The purposes are solved by a pres sure management system, a wheel , a rim, a kit , a vehicle , and a process according to the attached claims .

[0029] DETAILED DESCRIPTION

[0030] Further features and advantages of the present invention will best result from the following detailed description of its preferred forms of implementation, made with reference to the attached drawings and given for illustrative and non-limiting purposes . figure 1 schematically represents a bicycle equipped with an at least partially electronic wheel pressure management system according to the present invention;

[0031] - figure 2 represents the section of a bicycle wheel in figure 1 according to a plane I I radial to an axis of rotation of the wheel ;

[0032] - figure 3 represents the section of figure 2 in a configuration of charging the high-pressure chamber A through the opening of a passage from the environment outside the wheel C to chamber A;

[0033] - figure 4 represents the section of figure 2 in a configuration of inflating tire chamber B through opening a passage from A to B ;

[0034] - figure 5 represents the section in figure 2 in a configuration of deflating the tire chamber B by opening a passage from B to the environment outside the wheel C ; figure 6 represents an alternative implementation form to those in f igures 2 to 5 in which the pressuri zed chamber is outside the rim;

[0035] - figure 7 represents the section of figure 6 in a configuration of charging the high-pressure chamber A through the opening of a passage from the environment outside the wheel C to chamber A;

[0036] - figure 8 represents the section of figure 6 in a configuration of inflating tire B chamber through opening a passage from A to B ;

[0037] - figure 9 represents the section in figure 6 in a configuration of deflating the tire B chamber by opening a passage from B to the environment outside the wheel C ;

[0038] - figure 8 represents an additional alternative form of implementation to those in figures 2 to 6 in which the valve means comprise a plurality of valves , this form of implementation is depicted as a car wheel instead of a bicycle wheel , but this should not be considered limiting .

[0039] In the following we will describe various forms of implementation of the invention, especially with reference to the bicycle and automotive sectors , but these forms are relatable to any type of inflatable wheel and vehicle comprising it , and are therefore also interchangeable with each other .

[0040] Figure 1 shows a bicycle , preferably, pedal- assisted according to the present invention shown as a whole under reference number 1 .

[0041] Bicycle 1 includes a frame 5 , a pair of wheels 10 , both of which are equipped with inflatable tires 12 arranged on a rim 14 , an at least partially electronic management system of tire pressure 15 , hereafter referred to as the "management system" for brevity .

[0042] Bicycle 1 may be equipped with other electronic management systems , for example , at least one of the following : a shi fting management system, a pedal assist management system, a cyclocomputer, a tire pressure sensor and reporting system, a saddle height adj ustment system ( telescopic seatpost ) , a system for adj usting the hydraulics of the shock-absorbing elements ( fork and shock absorber ) .

[0043] The tire pressure management system 15 according to the present invention can be integrated with at least one of the other electronic systems on board the bicycle , i f any, such as sharing at least some components . Alternatively it may be a stand-alone system .

[0044] Generally, pressure management system 15 comprises :

[0045] - electronic command generation means 15a

[0046] - electronic actuation means 15b configured to implement commands generated by said electronic command generation means 15a .

[0047] In the implementation form of figure 1 said means of generation and implementation 15a and 15b are remote from each other and include means of wireless transmission 16a and wireless reception 16b of said commands , respectively .

[0048] The means of actuation 15b are arranged on wheel 10 , as shown below . The means of generating controls 15a are on a main body of the bicycle with respect to which wheel 10 is rotatable , e . g . they are connected to a handlebar .

[0049] In other forms of implementation not shown, the means of command generation 15a and the means of implementation 15b are both on wheel 10 , being, for example , integrated together, in which case the means of wireless transmission and reception 16a and 16b are not present .

[0050] Command generation means 15a include , for example , a pressure management application, related hardware means for its execution, and interface with a user . For example , hardware means include a memory in which the application is stored, a CPU for its execution, and a touch screen for input into the application by a user, as well as battery means for power supply . For example , 15a command generation means include a smartphone or are integrated with one of the other electronic management means mentioned above , such as a cyclocomputer . In the case of integration, the pressure management means 15 according to the present invention and the other management means may share at least in part a hardware component , such as a screen, memory, wireless transmission means , battery means for power supply, etc .

[0051] With reference to figure 2 , wheel 10 comprises :

[0052] - an airtight tire chamber A

[0053] - an airtight tire chamber B and distinct from chamber A, configured to be inflated and deflated 12 ; it is a chamber defined at least in part by the tire . By tire for the purposes of the present invention we mean both those of tubeless and inner tube type , in the latter case the inner tube is considered part of the tire and encloses said tire chamber . The figures illustrate the case of tubless tires , whereby said tire chamber is partly defined by the tire 12a and partly by the rim 14 . - a first communication passage 20 between the pressure chamber A and the tire chamber B

[0054] - a second communication passage 25 between tire chamber B and the environment outside wheel C ; a third communication passage 30 between pressure chamber A and the environment outside wheel C .

[0055] Chamber A is a rim chamber 14 , inside the rim . In particular, it will be noted that rim 14 includes a main body 14a and a tire 12 housing channel 14b . Chamber A i s internal to main body 14a .

[0056] Chamber A is made airtight by the valves described below, for that reason it comprises only valve openings , preferably presta or Schrader type , and is devoid of spoke attachment openings , such as holes for nipples , nipple passage or spoke insertion . Said spokeattachment openings may be on one or more walls separate from chamber A, so as not to flow into it . One of said walls with spoke attachment openings may, for example , be the back wall 14c .

[0057] Chamber A is a chamber configured to hold pressuri zed air, at a higher pressure than chamber B .

[0058] It is possible to provide a second chamber D inside the rim communicating with the outside C by means of said openings (not shown) for spoke attachment .

[0059] The means of actuation 15b are configured to electronically open and close at least said second communication passage 25 , plus preferably at least said second and third passages 25-30 alternately with each other, and even more preferably all said passages 20-25- 30 alternately with each other, based on respective commands received from the means of command generation 15a .

[0060] Said means of actuation 15a generally include at least one solenoid valve 40 , preferably three-way; means of battery 41 to supply said solenoid valve .

[0061] When present , the pressure sensing means 42 of chamber B may be part of the means of actuation 15a, being, for example , integrated with the solenoid valve 40 , or be separate , being, for example , coupled to the tire ; same for the wireless receiving means 16b .

[0062] Figures 2 to 9 represent one form of implementation of solenoid valve 40 , which should be considered as an example and not as a limitation .

[0063] The solenoid valve 40 includes an inlet 45 facing the external environment C and means of coupling 47 o f said inlet to inflation means (not shown) , which may be of known types . For example they include a pump, compressor or more generally any means of supplying gas at a pressure greater than environment pressure , external to the wheel 10 . Said means of attachment for example include a presta or Schrader type valve end .

[0064] A main channel 46 runs from the inlet 45 that connects the external environment C and the tire chamber B, where said main channel coincides with the third communication passage 30 .

[0065] Along said main channel 46 there are two communication openings to pressure chamber A, which reali ze the first and second passages 20 and 25 , respectively .

[0066] The solenoid valve 40 includes at least one opening and closing poppet 43 of the first and second movable passages that can be controlled between three positions , one in which it closes both passages , one that closes only the first , and one that closes only the second . The poppet 43 illustrated as an example operates by sliding, however, other modalities , such as rotary, are not excluded .

[0067] The solenoid valve comprises a first one-way valve 50 , i . e . , allowing flow in only one direction, arranged to allow or deny the passage of air into the main channel 46 , and interposed between the first and second passages 20 and 25 .

[0068] It is oriented so as to prevent the passage of air from the inlet 45 to the tire chamber B .

[0069] Solenoid valve 40 comprises a second one-way valve 52 , in main channel 46 , placed to separate inlet 45 on one side and first and second passages 20-25 on the other . The second one-way valve 52 is oriented so as to prevent the passage of air from tire chamber B to inlet 45 . The two one-way valves therefore have opposite orientations .

[0070] The first one-way valve 50 can be mechanical , that is , it can operate independently according to the pressure di f ference , while the second one-way valve 52 must necessarily be electronical ly controlled to allow deflation of the tire B chamber .

[0071] For completeness we note that the solenoid valve 40 generally includes half motors 44 to move the opening and closing shutters of the various passages .

[0072] Substantially, we can conclude that solenoid valve 40 is an at least partially electronic valve.

[0073] In use, in a first step illustrated in figure 3, system 15 issues a first command to control solenoid valve 40 to open the first passage 20. In this configuration, air can flow from inlet 45 to pressure chamber A. A user can then connect pressurized gas supply media (e.g., air) to inlet 45 and "charge" pressure chamber A, i.e., placing it at a higher pressure than both the pressure of the external environment C and a predetermined operating pressure of tire chamber B. The initial charging pressure of pressure chamber A can be, for example, in the range [10, 30] bar where 20 is a preferred value. However, wider ranges are not excluded, for example resulting from a tolerance of ± 20% of either or both extremes.

[0074] In a second step, the management system 15 issues a second control signal of solenoid valve 40 to open the second passage 25 while the first passage 20 is closed. This step allows the tire chamber B to be inflated to an operating pressure higher than the pressure of the external environment C. This operating pressure can be in the range of [1, 4] bar, for example. However, wider ranges are not excluded, for example resulting from a tolerance of ± 20% of either or both extremes.

[0075] In the second phase, the management system issues a termination signal, or interrupts the second signal, when the desired operating pressure is reached. Said signal of termination or interruption of the second signal can be done manually by a user who decides based on his or her personal perception when the tire is inflated to a level to his or her liking . Alternatively, and preferably, the management means are equipped with pressure sensors 42 , such as a pressure switch, capable of sensing the pressure in the tire chamber B . The management means 15 are in this case configured to terminate tire inflation by closing the second passage 25 upon reaching a predetermined first operating pressure o f the tire chamber B, which can be set by the user e . g . through said APP, or native in the system, or native and modi fied by the user .

[0076] In a third step, the management system 15 issues a third control signal of solenoid valve 40 to open the third passage 30 while the first and second passages 20- 25 are closed . This puts the tire chamber B in communication with the external environment and allows it to deflate .

[0077] In the third phase , the management system issues a termination signal , or interrupts the third signal , when the desired operating pressure is reached . Also in this case said signal of termination or interruption of the third signal can be done manually by a user who decides based on his or her personal perception when the tire is inflated to a level to his or her liking . Alternatively, and preferably, the management means are equipped with pressure sensors 42 , such as a pressure switch, capable of sensing the pressure in the tire chamber B . The management means 15 are in this case configured to terminate tire de flation by closing the third passage 30 upon reaching a predetermined second operating pressure of the tire chamber B, which can be set by the user e . g . through said APP, or native in the system, or native and modi fied by the user .

[0078] Advantageously, it is therefore possible to vary the operating pressure of the tire during use .

[0079] The charge pressure of pressure chamber A i s suf ficient to ensure at least one cycle of increase in operating pressure , preferably it is suf ficient to ensure more than one such cycle of increase .

[0080] Advantageously, it is also possible to use the management system to maintain the tire ' s operating pressure at a predetermined value , such as in case of leaks , minor punctures , or temperature changes . The holding pressure is set by a user, either native or native and modi fied by the user, and the management system 15 automatically increases or decreases the actual operating pressure in the tire chamber B by comparison with the holding pressure .

[0081] For this purpose , we do not exclude forms of implementation in which the management system only controls the opening and closing of the first and second passages ; in fact , this would be suf ficient to charge pressure chamber A and manage the operating pressure in chamber B in case of leaks or slight punctures .

[0082] In general , it is noted that the use of any other type of three-way solenoid valve i s not excluded, or two- way solenoid valves for the first and second passages in case only a minimalist pressure maintenance function is to be implemented .

[0083] Below we will describe alternative forms of implementations of the invention in which the same or similar elements will be referred to by the same reference numbers , or by the same numbers increased by 100 or multiples thereof .

[0084] Referring to figures 6, 7 , 8 , and 9 , an alternative form of implementation of a management system shown as a whole as number 115 is illustrated and di f fers from that previously described mainly for the fact that the pressure chamber A instead of being formed in the rim 14 , is external to it , defined by a pressure chamber body 160 , for example contained in the tire chamber B .

[0085] Also in this case you have the three passages 20 , 25 , 30 that can be opened and closed alternately with each other . The solenoid valve 140 can be three-way or two-way, depending on whether you want to actively vary the pressure or j ust implement a minimalist holding function as mentioned above .

[0086] The solenoid valve 140 could, for example , have at least one opening and closing poppet 143 that operates on a rotary instead of a sliding principle .

[0087] With reference to figure 10 , a third form of implementation is described, which in general advises of dividing among a plurality of valves the opening and closing functions of steps 20 , 25 and 30 said above . In particular, each of these passages can be implemented with a stand-alone valve .

[0088] The management system for the third form of implementation is indicated as a whole with 215 and, in a minimalist manner, can be configured to control only the automatic opening and closing of the second passage 25; in fact, this would be sufficient to manage the operating pressure in chamber B in case of leakage or slight punctures .

[0089] This in practice can be done, for example, by using a single solenoid valve 240 that handles only the opening and closing of the second passage 25 based on commands processed from data measured by the pressure sensors 42 of the tire chamber B.

[0090] The first and third passages 20 and 30 can be handled by mechanical check valves 240b, that is, acting according to the pressure difference, such as common known tire valves, e.g., presta or schrader type.

[0091] Means of cmmand generation 215a and actuator means 215b can both be on wheel 10, e.g., integrated, e.g., in the absence of wireless transmission and reception means.

[0092] Many other forms of implementation not illustrated are naturally included in the present invention, arising, for example, from varying the number of valves used and which passages are opened and closed by electronic controls. As an example, we mention a form of implementation in which the "charging" of the pressure chamber A is enabled by a mechanical check valve, e.g., of the "presta or schrader" type placed to handle the opening and closing of the first passage 20 by pressure difference .

[0093] In the same form of implementation, the opening and closing of the second and third passages 25 and 30 can be operated by electronic controls .

[0094] It is not excluded in such a case that a single solenoid valve handles all said passages by also integrating the mechanical check valve , or that the latter is separate .

[0095] The choice depends among other things on the si ze of the rim, which in the bicycle industry is very smal l and has limited possibilities of puncture so in that case the solution of a single solenoid valve incorporating all functions , including that of mechanical check valve , is preferred .

[0096] According to some variations not illustrated, said single solenoid valve can be configured to also allow direct passage of air from the external environment C to the tire chamber B to allow direct inflation of the tire without passing through the pressure chamber A, in addition or alternatively this function can also be ful filled by a traditional mechanical check valve , e . g . distinct from solenoid valve 40 , preferably of presta or schrader type .

[0097] Finally, we note that we also do not exclude the possibility that the opening and closing of each of passages 20 , 25 and 30 alternately is done by mechanical check valves only . At the very least , this allows for a quick emergency inflation function after any puncture repair without having to use a pump or compressor .

[0098] In general , the means used for opening and closing passages 20 , 25 and 30 are called opening and closing means 90 , whether they are solenoid valves included in the implementation means , or mechanical valves or their additions .

[0099] Regarding the pressure chamber A we generally observe that preferably it extends along an entire circumference coaxial to the axis of rotation of wheel 10 . This advantageously facilitates the balancing of the wheel . This can also facilitate the construction of the wheel since the pressure chamber A can, for example , be made by extrusion or molding during the construction of the rim .

[0100] Finally, we note that the management system described so far can be native on a vehicle , such as a bicycle , or it can be produced as a kit that can be applied to existing bicycles .

[0101] The management system is easily associated with an e-bike in that it can be integrated with other electronic controls already present on such bicycle .

[0102] GENERAL MEANING OF TERMS

[0103] In understanding the purpose of the present invention, the term " comprising" and its derivatives , as used herein, are intended as open-ended terms specifying the presence of the declared characteristics , elements , components , groups , integers and / or phases , but not excluding the presence of other undeclared characteristics , elements , components , groups , integers and / or phases . The above also applies to words with similar meanings such as the terms " including" , "having" and their derivatives . In addition, the terms "part" , "section", "portion", "member" or "element" when used in the singular may have the dual meaning of a single part or a plurality of parts. As used herein to describe the form(s) of implementation mentioned above, the following directional terms "forward", "backward", "above", "below", "vertical", "horizontal", "underneath" and "transverse", as well as any other similar directional terms refer to the form of implementation described in the operative position. Finally, grade terms such as "substantially", "about" and "approximately" as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed.

[0104] While only selected implementation forms have been chosen to illustrate the present invention, from this description it will be clear to those expert in the field that various modifications and variations may be made without departing from the purpose of the invention as defined in the attached claims. For example, the size, shape, position or orientation of the various components may be modified as needed and / or desired. Components shown directly connected or in contact with each other may have intermediate structures interposed between them. The functions of one element can be performed by two and vice versa. The structures and functions of one form of implementation can be adopted in another one. It is not necessary that all advantages are present in a particular form of implementation at the same time. Each characteristic that is original compared to the prior art , alone or in combination with other characteristics , should also be considered a separate description of further inventions by the applicant , including structural and / or functional concepts incorporated by those characteri stics . Therefore , the previous descriptions of implementation forms according to the present invention are provided for illustrative purposes only and not for the purpose of limiting the invention as defined by the attached claims and their equivalents .

Claims

CLAIMS1. Pressure management system for at least one inflatable tire, comprising:- at least one wheel (10) including at least one inflatable tire;- at least one first airtight chamber A;- at least a second inflatable chamber B and at least partially defined by said tire, chamber B being airtight and distinct from chamber A; a first communication passage (20) between chamber A and chamber B a second communication passage (25) between chamber B and an environment external to wheel C; a third communication passage (30) between chamber A and external environment C;- opening and closing means (40, 140, 240, 240b) configured to alternately open and close said passages to each other.

2. System according to claim 1, characterized by the fact that:- said chamber A is, or is configured to be, at a pressure higher than said chamber B, and- chamber B is, or is configured to be, at a pressure higher than the atmospheric pressure of environment C.

3. System according to claim 1 or 2 characterized by the fact that the wheel includes a rim placed tosupport the tire, where chamber A is one of the following :- a chamber of the rim;- an inner chamber of chamber B.

4. System according to any claim from 1 to 3 characterized by the fact that at least the third passage includes means of connection (45, 47) to means of supplying pressurized gas outside the wheel.

5. System according to any claim from 1 to 4 characterized by the fact that it comprises:- electronic command generation means 15a;- electronic actuation means (15b) configured to implement commands generated by said electronic command generation means (15a) , where said electronic means of actuation (15b) include at least one of the following opening and closing means :- opening and closing means (40, 140, 240) of at least one of said passages (20, 25, 30)- opening and closing means (40, 140) of at least two of said passages (20, 25, 30) opening and closing means (40, 140) of all three of said passages (20, 25, 30) .

6. System according to claim 5, characterized by the fact that it comprises pressure sensors (42) of chamber B.. System according to claim 5 or 6, characterized in that said means of generating electronic commands (15a) are remote from the means of electronic actuation (15b) and include means of wireless transmission (16a) and means of wireless reception (16b) of said commands, respectively.System according to any claim from 5 to 7, characterized by the fact that said electronic means of actuation comprise at least one three-way solenoid valve defining said first second and third passage (20, 25, 30) .

9. System according to any of the previous claims, characterized by the fact that:- said first and second passages (20, 25, 30) are connected to said third passage,- said third passage accommodates a first check valve (50) to prevent the passage of air from chamber B to the external environment C and to allow it in the opposite direction, wherein said check valve (50) is arranged to separate from each other the connection points of the third passage to the first and second passages (20, 25) .

10. System according to claim 9, characterized by the fact that the third passage (30) comprises a second check valve (52) opposite to the first check valve (50) and arranged to separate the external environment C from both the first and second passages (20, 25) , the latterbeing electronically controlled.

11. Support rim of an inflatable tire of a wheel, the rim comprising means of coupling to a tire (14b) and a chamber A communicating with the outside solely by one or more openings each configured to receive a respective airtight valve.

12. Rim according to claim 11, characterized by the fact that said openings are configured to accommodate respective Presta or Schrader type valves.

13. Rim according to claim 11 or 12, characterized by the fact that it comprises a plurality of ray attack openings on one or more walls (14c) separated from chamber A.

14. Wheel including a rim according to any claim from 11 to 13 and an inflatable tire, where the wheel includes :- at least one first airtight chamber A;- at least a second inflatable chamber B and at least partially defined by said tire, chamber B being airtight and distinct from chamber A; a first communication passage (20) between chamber A and chamber B a second communication passage (25) between chamber B and an environment external to wheel C; a third communication passage (30) between chamber A and external environment C;- opening and closing means (40, 140, 240, 240b) configured to alternately open and close said passages to each other.

15. Inflatable wheel kit characterized by the fact that it comprises:- an airtight chamber A inside a wheel rim or insertable into an inflatable chamber B of a wheel; a first communication passage (20) between chamber A and an inflatable chamber B of said wheel; a second communication passage (25) between chamber B and an environment external to wheel C; a third communication passage (30) between chamber A and external environment C;- opening and closing means (40, 140, 240, 240b) configured to alternately open and close said passages to each other.

16. Vehicle comprising: at least one wheel comprising an inflatable tire; and a pressure management system for said tire according to any claim from 1 to 10.

17. Vehicle according to claim 16, characterized by the fact that it is a pedal-assist bicycle and the pressure management system is an electronic system integrated with an electronic pedal-assist management system.18 . Pressure management procedure of at least one inflatable tire , characteri zed by the following steps :- prepare a vehicle according to claims 16 or 17 ;- introduce pressuri zed air into chamber A to a value , called the charge pressure ; bring chamber B to an initial operating pressure lower than the charge pressure by commanding the withdrawal of pressuri zed gas from chamber A.19 . Procedure according to claim 18 , characteri zed by the following steps :- command the deflation of chamber B to a second operating pressure lower than the first operating pressure by releasing gas from chamber B to the external environment C ;- command the inflation of chamber B to a third operating pressure higher than the second operating pressure and lower than the charge pressure by taking pressuri zed gas from chamber A.20 . Procedure according to claim 19 , characteri zed by repeating the cycle of deflating and inflating chamber B .

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