Device able to exert a thrust on a door or any other vertical flat surface such as a partition, comprising a lower support bar, an intermediate support sole and an upper support bar, each of said lower support bar and upper support bar respectively being capable to be actuated in telescopic extension, wherein the device can be dismantled into at least 3 parts (1-1, 1-2,1-3) and comprises a first reversible fastening device (4c-4d) and a second reversible fastening device (7g-7h) that can be manually activated and deactivated, said fastening devices being capable of reversibly fastening the lower parts (4a, 7b) and upper parts (4b,7a) of each of said lower support bar and upper support bar, respectively, and able to maintain said lower support bar and upper support bar in rectilinear alignment when they are actuated in said telescopic extension, wherein: - said lower support bar comprises a lower part comprising a jack, said jack comprising a jack body, the lower end of which is preferably fixed or able to be fixed so as to be articulated in rotation (4r1) on a lower support sole, and a first jack rod, and an upper part of the lower support bar being fixed or able to be fixed in a rotationally articulated manner (4r2) to said intermediate sole, - said upper support bar comprises a lower part fixed or able to be fixed in a manner articulated in rotation (7r1) to and relative to said intermediate sole, and an upper part of the upper support bar comprising an upper support device (7a1), said upper support bar being able to be actuated in telescopic extension to vary the distance between said lower part and upper part of the upper support bar, - said first jack rod is fixed or able to be fixed in a reversible manner via the first reversible fastening device (4-2c, 4b1, 4c-4d) to said upper part of the lower support bar, the telescopic actuation of said first jack rod being able to vary the distance between said jack body (4a1) and said upper part of the lower support bar, said first reversible fastening device (4-2c, 4b1, 4c-4d), when activated, being able to maintain said upper part of the lower support bar in rectilinear alignment with said first jack rod to which it is fixed during the telescopic actuation of said first jack rod, - said upper support bar comprises or cooperates with a second rod extending at least partly inside (7c1) said upper support bar, said second rod being manually or electrically operable in said telescopic extension to vary said distance between said lower part and said upper part of the upper support bar, said second rod being fixed or capable of being fixed in a reversible manner via the second reversible fastening device (7a2, 7d, 7g, 7h) to said upper part of the upper bar support, said second fastening device (7a2, 7d, 7g, 7h) when activated being able to hold said lower part and said upper part of the upper bar support, fixed to each other in rectilinear alignment with each other during telescopic actuation of said second rod. - said lower support bar comprises a lower part comprising a jack, said jack comprising a jack body, the lower end of which is preferably fixed or able to be fixed so as to be articulated in rotation (4r1) on a lower support sole, and a first jack rod, and an upper part of the lower support bar being fixed or able to be fixed in a rotationally articulated manner (4r2) to said intermediate sole, - said upper support bar comprises a lower part fixed or able to be fixed in a manner articulated in rotation (7r1) to and relative to said intermediate sole, and an upper part of the upper support bar comprising an upper support device (7a1), said upper support bar being able to be actuated in telescopic extension to vary the distance between said lower part and upper part of the upper support bar, - said first jack rod is fixed or able to be fixed in a reversible manner via the first reversible fastening device (4-2c, 4b1, 4c-4d) to said upper part of the lower support bar, the telescopic actuation of said first jack rod being able to vary the distance between said jack body (4a1) and said upper part of the lower support bar, said first reversible fastening device (4-2c, 4b1, 4c-4d), when activated, being able to maintain said upper part of the lower support bar in rectilinear alignment with said first jack rod to which it is fixed during the telescopic actuation of said first jack rod, - said upper support bar comprises or cooperates with a second rod extending at least partly inside (7c1) said upper support bar, said second rod being manually or electrically operable in said telescopic extension to vary said distance between said lower part and said upper part of the upper support bar, said second rod being fixed or capable of being fixed in a reversible manner via the second reversible fastening device (7a2, 7d, 7g, 7h) to said upper part of the upper bar support, said second fastening device (7a2, 7d, 7g, 7h) when activated being able to hold said lower part and said upper part of the upper bar support, fixed to each other in rectilinear alignment with each other during telescopic actuation of said second rod.