the example of realization mode for the door stop device proposed by the present invention is constituted by ( fig1 ): a guiding arm ( 1 ), preferably articulated at one end , advantageously formed by a metallic rod or with other resistant material , providing at least one rolling track , preferably two , on opposite faces . this guiding arm may be fastened to the opening part of the door or to the frame of the door . cross section of guiding arm ( 1 ) may be variable , in a way that the opposite faces providing rolling tracks are not necessarily kept parallel on their total length . in addition , notches or bosses may be defined on the rolling tracks of guided arm ( 1 ), in order to obtain some areas more or less easy to roll on . a blocking mechanism ( 2 ), which is allowed a limited displacement relatively to guiding arm ( 1 ), the said blocking mechanism ( 2 ) being fastened to the opening part of the door or to the frame of the door , in order to cooperate with guiding arm ( 1 ) and provide the blocking function for guiding arm ( 1 ), in any position , as long as the door is not submitted to a load that would exceed the unlocking force . the said blocking mechanism ( 2 ) comprises ( fig1 ): a braking roller ( 21 ), mounted on its axle ( 22 ). lateral guiding slots ( 23 a ) and ( 23 b ) ( fig2 ), along which axle ( 22 ) of braking roller ( 21 ) is free to move with a limited amplitude and in a parallel direction to guiding arm ( 1 ), the said lateral guiding slots ( 23 a ) and ( 23 b ) being possibly defined with notches and / or bosses that may alter the displacement of axle ( 22 ). in this way , braking roller ( 21 ) is mounted on blocking mechanism ( 2 ), free to move with a limited amplitude and in a parallel direction to guiding arm ( 1 ). a braking element ( 24 ), ( fig3 ), which cooperates with braking roller ( 21 ), ( fig1 ), the said braking element ( 24 ) being itself mounted on blocking mechanism ( 2 ), and being allowed to move in a direction globally perpendicular to guiding arm ( 1 ), in a way that the said braking element ( 24 ) may be set apart from braking roller ( 21 ), in order to release said braking roller ( 21 ). it is then easy to understand that while braking element ( 24 ) is pressed against braking roller ( 21 ), the said braking element ( 24 ) prevents blocking roller ( 21 ) from rotating ; the said blocking roller ( 21 ) being linked to blocking mechanism ( 2 ) and permanently in contact with guiding arm ( 1 ), this provides a relative locking between guiding arm ( 1 ) and blocking mechanism ( 2 ). the invention sets that braking element ( 24 ) may be activated by the displacement of mobile interface unit ( 25 ), described hereafter , ( fig4 ) and ( fig5 ), through the means of a mechanical link constituted here , as a non restrictive example , by pins ( 241 a ), ( 241 b ), ( 241 c ) and ( 241 d ) located on braking element ( 24 ) and facing oblong slots , respectively ( 254 a ), ( 254 b ), ( 254 c ) and ( 254 d ), located on mobile interface unit ( 25 ). it is then easy to understand that when mobile interface unit ( 25 ) is displaced relatively to blocking mechanism ( 2 ), due to the displacement of axle ( 22 ), which is then released from notches ( 251 a ) and ( 251 b ) described hereafter , the said mobile interface unit ( 25 ) pulls braking element ( 24 ) apart from braking roller ( 21 ), allowing the said braking roller ( 21 ) to rotate . the invention also sets that braking element ( 24 ), ( fig3 ), may be submitted to elastic means ( 242 a ), ( 242 b ), ( 242 c ) and ( 242 d ), intended to bring braking element ( 24 ) back to locked position , pressed against braking roller ( 21 ). in the proposed realization mode , the said elastic means ( 242 a ), ( 242 b ), ( 242 c ) and ( 242 d ) are constituted by elastic blades fastened to braking element ( 24 ), the said elastic blades comprising bosses ( 2421 a ), ( 2421 b ), ( 2421 c ) and ( 2421 d ) located at their extremity , the said bosses being located in front of notches ( 27 a ) and ( 27 b ) which are provided on the faces of the blocking mechanism ( 2 ), ( fig2 ). a mobile interface unit ( 25 ), ( fig4 ), itself mounted on blocking mechanism ( 2 ) and allowed to move in a direction globally perpendicular to guiding arm ( 1 ), in a way that said mobile interface unit ( 25 ) may compress elastic means ( 26 ) described hereafter , when axle ( 22 ) of braking roller ( 21 ) is displaced along guiding slots ( 23 a ) and ( 23 b ), the said guiding slots being placed in the lateral faces of blocking mechanism ( 2 ). the said mobile interface unit ( 25 ) comprises , for this purpose , bearing means designed to transfer the efforts produced by the elastic means to the axle of the braking roller ; the said bearing means are constituted by notches ( 251 a ) and ( 251 b ), and ramps with an incline ( 252 a ), ( 252 b ), ( 252 c ) and ( 252 d ), ( fig4 and 5 ), in contact with axle ( 22 ) of braking roller ( 21 ). then , when axle ( 22 ) of braking roller ( 21 ) slides along lateral guiding slots ( 23 a ) and ( 23 b ), ( fig6 ), in a direction parallel to guiding arm ( 1 ), said axle ( 22 ) is removed from notches ( 251 a ) and ( 251 b ) located on mobile interface unit ( 25 ), to reach respectively inclined ramps ( 252 a ) and ( 252 c ), or ( 252 b ) and ( 252 d ). the mobile interface unit ( 25 ) is then submitted to a displacement globally perpendicular to the displacement of axle ( 22 ), which allows said mobile interface unit ( 25 ) to compress elastic means ( 26 ). in this way , axle ( 22 ) of braking roller ( 21 ) is submitted to forces generated by elastic means ( 26 ), the said forces being transmitted by mobile interface unit ( 25 ). elastic means ( 26 ), ( fig1 ), linked to blocking mechanism ( 2 ) are drawn schematically as a coil spring , for example . then , the mobile interface unit ( 25 ), being pressed by elastic means ( 26 ), tends to retain axle ( 22 ) of roller ( 21 ) in the notches ( 251 a ) and ( 251 b ), the hold force depending on the load generated by elastic means ( 26 ), but also depending on the depth as well as on the incline of the ramps of said notches ( 251 a ) and ( 251 b ). it is easy to understand that the deeper notches ( 251 a ) and ( 251 b ) will be , the bigger the force to release axle ( 22 ), which allows to define the hold force provided by the door stop device . in addition , as soon as axle ( 22 ) has been released from notches ( 251 a ) et ( 251 b ), due to a sufficient load applied on guiding arm ( 1 ), braking roller ( 21 ) is then released from braking element ( 24 ), the said braking element ( 24 ) being set apart from braking roller ( 21 ) due to the displacement of mobile interface unit ( 25 ), said axle ( 22 ) being submitted to the pressure of inclined ramps ( 252 a ), ( 252 c ) or ( 252 b ), ( 252 d ) ( fig6 ), the said ramps transferring the forces generated by elastic means ( 26 ) with a bigger or smaller incline relative to the direction of guiding arm ( 1 ). then , when the incline of ramps ( 252 a ), ( 252 c ) or ( 252 b ), ( 252 d ) is small relative to guiding arm ( 1 ), the resulting force applied to axle ( 22 ) in a direction parallel to guiding arm ( 1 ) will remain limited , although at the same time , elastic means ( 26 ) provide a relatively big force , due to the compression of said elastic means ( 26 ). in this way , it is possible to balance the forces between , on the one hand , the resulting load coming from elastic means ( 26 ) which are transferred by mobile interface unit ( 25 ) in a direction parallel to guiding arm ( 1 ), and which tend to bring axle ( 22 ) back into the locked position , inside notches ( 251 a ) and ( 251 b ), and on the other hand , the friction forces due to the rotation of braking roller ( 21 ) along guiding arm ( 1 ), the said friction forces being intentionally of a limited amplitude . then , when the movement of the door during opening or closing maneuvers is interrupted , the said friction forces due to the rotation also disappear , and axle ( 22 ) being only submitted to the load of elastic means ( 26 ), the said load being transferred by inclined ramps ( 252 a ), ( 252 c ) or ( 252 b ), ( 252 d ) ( fig6 ), the said axle ( 22 ) is then brought back into the locked position , inside notches ( 251 a ) and ( 251 b ). the door stop unit is then in locked position . in a preferred realization mode , a variation of elastic means ( 26 ) may be constituted by elastic blades ( 253 a ), ( 253 b ), ( 253 c ) and ( 253 d ), linked to mobile interface unit ( 25 ) and comprising bosses ( 2531 a ), ( 2531 b ), ( 2531 c ) and ( 2531 d ) located at their free extremity , the said bosses being located in front of notches ( 28 a ) and ( 28 b ) which are located on the faces of blocking mechanism ( 2 ), ( fig5 and 7 ). the advantage of this solution is a volume reduction compared to a solution using a coil spring . the door stop device proposed by this invention may comprise at least one roller ( 3 ), intended to counterbalance the load generated by braking roller ( 21 ) on guiding arm ( 1 ). the said roller ( 3 ) may be mounted with free rotation on an axle ( 31 ), which is itself directly linked to blocking mechanism ( 2 ) or indirectly through a bracket ( 32 ). ( fig1 ). in addition , axle ( 31 ) of roller ( 3 ) may be guided by oblong slots ( 23 c ) and ( 23 d ) provided in the lateral faces of blocking mechanism ( 2 ). ( fig2 ). in addition , the said roller ( 3 ) may be submitted to elastic means ( 4 ), drawn schematically as a coil spring , the load being transferred directly or through bracket ( 32 ). it is easy to understand that the use of roller ( 3 ) allows to balance the load generated by roller ( 21 ) on guiding arm ( 1 ). in addition , notches or bosses may be provided on the side of guiding arm ( 1 ) which is in contact with roller ( 3 ), in order to potentially form some zones with more or less rolling resistance , as it may be defined on existing state of the art door stop systems . variation of braking roller ( 21 ) ( fig8 and 9 ): it is proposed to place besides braking roller ( 21 ) at least one additional roller , so called friction roller ( 211 ), which is mounted on the same axle as braking roller ( 21 ) and without any contact with guiding arm ( 1 ), and said friction roller ( 211 ) comprises some rough surfaces that are in contact with said braking roller ( 21 ). when braking roller ( 21 ) is displaced and starts rotating along guiding arm ( 1 ) in the unlocked mode , said friction roller ( 211 ) is intended to be blocked , either by entering into contact with a rough part of blocking mechanism ( 2 ), the said rough part being possibly constituted by elements ( 29 a ) or ( 29 b ) fastened to blocking mechanism ( 2 ), or by entering into contact with a rough part of mobile interface unit ( 25 ), said rough part being possibly constituted by a rough surface not shown on the schematic drawings , but which may provide sufficient roughness to brake friction roller ( 211 ). this configuration ensures that a friction force appears between braking roller ( 21 ) while it is rotating along guiding arm ( 1 ), and friction roller ( 211 ) which is blocked by being in contact with elements ( 29 a ) or ( 29 b ), or otherwise blocked by being in contact with a rough part of mobile interface unit ( 25 ). it may be noticed that elements ( 29 a ) or ( 29 b ) may be mounted on blocking mechanism ( 2 ), through a flexible link in order to allow a free displacement of axle ( 22 ) of braking roller ( 21 ) inside oblong slots ( 23 a ) and ( 23 b ). in the realization mode presented here as an example , friction roller ( 211 ) is mounted in the central part of braking roller ( 21 ) and with the same axis , in a way that both lateral flanges of said friction roller ( 211 ) are in contact with corresponding flanges of braking roller ( 21 ). braking roller ( 21 ) will therefore have an adapted shape , with a central zone offering an appropriate clearance . ( fig8 ). it may be observed that it is possible to reverse this configuration and design a variation where braking roller ( 21 ) is placed in the central part of friction roller ( 211 ). in addition , in the realization mode presented here as an example , the diameter of friction roller ( 211 ) is slightly bigger than the diameter of braking roller ( 21 ). in order to prevent any contact between said friction roller ( 211 ) and guiding arm ( 1 ), the cross section of said guiding arm ( 1 ) may be shaped as a u , ensuring a contact with braking roller ( 21 ) on the external parts of the track and avoiding any contact with friction roller ( 211 ) along the central part of the track . ( fig8 ) variation of elastic means ( fig1 ): in a preferred realization mode described here above , elastic means ( 26 ) cooperating with mobile interface unit ( 25 ), may be constituted by elastic blades ( 253 a ), ( 253 b ), ( 253 c ) and ( 253 d ), linked to mobile interface unit ( 25 ) and comprising bosses ( 2531 a ), ( 2531 b ), ( 2531 c ) and ( 2531 d ) located at their free extremity , the said bosses being located in front of notches ( 28 a ) and ( 28 b ) which are located on the faces of blocking mechanism ( 2 ), ( fig5 and 2 ). the invention proposes to modulate the value of the load generated by elastic means ( 253 a ), ( 253 b ), ( 253 c ) and ( 253 d ), depending on the incline of blocking mechanism ( 2 ), in order to increase the hold force in locked mode , in the case the door stop device fitted on a vehicle would be inclined , the said vehicle being parked on a slope for example . in the realization mode presented here as an example , elastic means ( 253 a ), ( 253 b ), ( 253 c ) and ( 253 d ), linked to mobile interface unit ( 25 ), on the one hand , and elastic means ( 26 aa ), ( 26 ab ), ( 26 ac ) and ( 26 ad ), linked to block ( 26 a ), on the other hand , are constituted by elastic blades comprising bosses located at their free extremity , the said bosses being located in front of notches which are located on the faces of blocking mechanism ( 2 ), ( fig1 ). block ( 26 a ) is itself mounted in a way to allow a displacement relatively to blocking mechanism ( 2 ), the said displacement being in the same direction as the displacement of mobile interface unit ( 25 ). superior face ( 255 ) of mobile interface unit ( 25 ) is fitted with a cavity ( 2551 ) with inclined faces , the said cavity ( 2551 ) may hold a spherical ball ( 2552 ), which remains in its place by simple effect of gravity , as long as the incline of blocking mechanism ( 2 ) remains lower than the slope of the inclined faces of cavity ( 2551 ). inferior face of block ( 26 a ) is also fitted with a cavity ( 26 af ), placed in front of cavity ( 2551 ), in a way that when mobile interface unit ( 25 ) is displaced , face ( 255 ) of said mobile interface unit ( 25 ) may come close to face ( 26 ae ) of block ( 26 a ), without having the spherical ball ( 2552 ), which remains in its cavity ( 2551 ), be in contact with block ( 26 a ), ( fig1 ). as a result of this pattern , when spherical ball ( 2552 ) remains located in cavity ( 2551 ) due to the effect of gravity , only the elastic means ( 253 a ), ( 253 b ), ( 253 c ) and ( 253 d ), are displaced and therefore compressed to generate a load on mobile interface unit ( 25 ), while elastic means ( 26 aa ), ( 26 ab ), ( 26 ac ) and ( 26 ad ), are not triggered and do not generate any load on the said mobile interface unit ( 25 ). on the contrary , when the inclination of the blocking mechanism ( 2 ) exceeds a given threshold which allows the spherical ball ( 2552 ) to move out of its cavity ( 2551 ), said spherical ball ( 2552 ) may roll in between faces ( 255 ) and ( 26 ae ), then providing a mechanical link between mobile interface unit ( 25 ) and block ( 26 a ), ( fig1 ). in this case , any displacement of mobile interface unit ( 25 ) generates a displacement of block ( 26 a ) in the same direction , which leads to a compression of elastic means ( 26 aa ), ( 26 ab ), ( 26 ac ) and ( 26 ad ). in this way , the loads generated by elastic means ( 253 a ), ( 253 b ), ( 253 c ) and ( 253 d ), on the one hand , and elastic means ( 26 aa ), ( 26 ab ), ( 26 ac ) and ( 26 ad ), on the other hand , become cumulative , then providing a bigger load on mobile interface unit ( 25 ). it may be noticed that in some applications , spherical ball ( 2552 ) may be replaced by a cylinder , not described here , provided the shapes of cavities ( 2551 ) and ( 26 af ) be adapted consequently .