in order that the present invention may more readily be understood , the following description is given , merely by way of example , reference being made to the accompanying drawings . the device for inflating / deflating the shoulder straps is referred to in its entirety as ( 1 ) and has applications for packs , satchels ( 2 ) and , generally speaking , any article that can be worn on the back by a user and which demands the use of shoulder straps that press onto the user &# 39 ; s shoulders . the shoulder straps are made in a known manner of fabric or any other material and are attached at one end ( 3 a ) to the rear wall ( 2 a ) or shell of the satchel by any known appropriate means and to a quick - release fastener at the other end ( 3 b ) allowing connection to a strap ( 4 ) joined to the lower part ( 2 b ) of the satchel . according to the invention , the inflation / deflation device ( 1 ) is incorporated in a one - piece part ( 5 ) herein referred to as a pad constituting the means of guiding and adjusting the length of the strap , said part itself being connected to the shoulder strap by making the means of inflation member ( 6 ) communicate with an inflatable cushion ( 7 ) incorporated in the shoulder strap . a device of this type is provided on each shoulder strap of the satchel . the inflation member is formed of a resilient material that can be deformed as illustrated in fig6 . the one - piece part ( 5 ) forming a shaped pad is made of any appropriate material and is devised to fulfil four functions , namely : connection to one of the ends ( 3 b ) of said shoulder strap ( 3 ), allowing the injection of inflating air , connection to the length - adjustment strap ( 4 ) in order to adjust the carrying position of the satchel for the user . the pad of the one - piece part ( 5 ) is shaped in any appropriate manner with a flat cross section and may have a well styled , attractive appearance . the pad of the one - piece part ( 5 ) is advantageously made in two parts with a base ( 5 a ) and a cover ( 5 b ), the latter being separately mounted and fixed by bonding or other means . the stretched - shape base has , in its central part ( 5 a 1 ), a cavity ( 5 a 2 ) making it possible to position the inflation means ( 6 ) which must be connected to cushion ( 7 ). the base has an opening ( 5 a 3 ) in its thickness located in the above - mentioned central part and accommodating a shaft ( 8 ) integrally made during the manufacture of the pad and making it possible to guide and deflect the adjustment strap ( 4 ) that is physically connected to the pack or satchel . said base ( 5 a ) also comprises , at one of its ends , a tunnel shape ( 5 a 4 ) making it possible to guide and attach the end ( 3 b ) of the shoulder strap by any appropriate means . this tunnel shape ( 5 a 4 ) is shaped to permit and provide room for the connecting tube ( 9 ) between the inflation means ( 6 ) and cushion ( 7 ) incorporated in the shoulder strap . said inflation member includes a bulb shape ( 6 a ) intended to be centred in the central part of the cavity of the pad , said bulb extending as a pipe ( 6 b ) capable of penetrating into said part forming a tunnel ( 5 a 4 ) on the one hand , and permitting , on the other hand , connection to the cushion by means of an appropriate connecting tube ( 9 ). the pipe part ( 6 b ) is capable of fitting into a recess that matches its shape made in the thickness of the pad , this recess being arranged advantageously in the median axial plane of the pad . said pipe ( 6 b ) is therefore maintained securely in position . communication between the pipe ( 6 b ) and bulb ( 6 a ) is via a reduced - diameter channel ( 6 c ) that delimits on the bottom of the pipe a seat shape of which the function will be specified below . vertically above the area where the pipe and reduced - diameter channel are connected , there is provision for an additional protruding bump ( 6 d ) capable of receiving , during certain phases , a ball ( 10 ) of small cross - sectional area . this ball is pushed into the pipe by a spiral spring ( 11 ) that is suitably guided into the latter , said ball blocking off the connecting channel ( 6 c ) between the bulb and the pipe when the inflation / deflation means is not in use . spring ( 11 ) is secured in said pipe by a retention lip ( 6 e ) formed on the outside of the pipe . cover ( 5 b ) which is separately mounted on the pad is devised with two circular openings ( 5 b 1 - 5 b 2 ) of appropriate size to surround and protect , on the one hand , the bulb part 6 a of the inflation means and , on the other hand , the bump part 6 d of the air pipe , leaving the protruding projecting parts of the bulb and of the bump visible . cushion ( 7 ) which is linked to inflation means ( 6 ) is long and is inserted inside the actual shoulder strap . in a known manner , this cushion may comprise various chambers that communicate with each other making it possible to split up the inflation zone into segments . the connecting tube between the cushion and the inflation device is made in any appropriate manner . the operation of the device will now be described . each shoulder strap of the satchel or pack is devised with such a device . the end of the shoulder strap is attached , as stated previously , on the pad by any appropriate known means and the cushion is made to communicate with the inflation device via the intermediate tube . the lower strap attached to the pack or satchel has been inserted into the lower part of the pad into the opening so that the entire assembly is securely held . when not in use , the shoulder straps are not inflated . when the user has correctly put the satchel or pack onto their back , the shoulder straps are located over the individual &# 39 ; s chest . using the right or left hand , the user simply needs to press the bulb as shown in fig6 in order to ensure inflation . the pressure exerted on the bulb makes it possible to expel the air and push the ball in opposition to the spring in the connecting pipe , the air then being forced into the cushion located inside the shoulder strap . the user repeats this operation several times in order to obtain the desired inflation pressure . after inflation , the inflation bulb is no longer used and the ball , under the effect of the spring &# 39 ; s decompression force , returns to its original position , thus blocking off the seating of the bottom of the pipe . to ensure the deflation function shown in fig7 the user simply has to press on the bump 6 d of the pipe , this pressure causes displacement of the ball in the pipe and frees the reduced - diameter channel between the bulb and the pipe . the air can escape into the bulb and into the outside atmosphere through an opening in the bulb . the cushion is gradually deflated until all the air is evacuated . the device according to the invention is very simple to produce and operate . according to the invention , the inflation / deflation device is entirely integrated into the support pad which also provides connection to the lower strap . the entire device is produced so that its various components cannot be tampered with because only the bulb and the deflation means can be accessed . the pad may also be of any appropriate shape and profile . the area where the lower strap is connected and deflected may be arranged differently , for instance , at the end of the pad opposite the area where the shoulder strap is attached . as well as its functional aspect , the inflation device therefore helps give the pad its special attractive appearance . the user can , depending on the load , adjust , in each shoulder strap , the inflation pressure , thus obtaining optimum comfort at their discretion . the integral cushion in the shoulder strap is of any appropriate shape and design .