FLAT JACKS

If existing structures have to be held up by means of piles or beams, it is sometimes necessary to preload the supporting section. This preloading can be effected with a flat jack, which is generally left behind in the structure.

The flat jack consists of a steel casing, the dimensions of which are enlarged by injecting it with mortar. The flat jack has a very small overall height. It can exert very large forces.

The flat jack is built up of two steel dishes welded together. The jack has two connections: a supply tube and breather tube opposite each other. These connections are 50 mm long and have a 3/8" G screw thread. Flat jacks are available with connecting tubes in other positions. The standard shape is round, but a square or an oval shape is also available.

Depending on the application water, oil, cement mortar or synthetic resin are injected to put the jacks under pressure. The maximum operating pressure is 150 bars. As the stroke of the jack increases, the effective surface area of the jack decreases, so that the force becomes less. If the stroke of one jack is insufficient, two or more jacks can be put on top of each other.

The jack is placed between two steel plates or is set in concrete. The height of the smallest jack, including the steel plates is 30 mm.

APPLICATIONS OF FLAT JACKS:

TECHNICAL INFORMATION ON FLAT JACKS:

external diam. stroke maximum force dimensions steel plates overall height
in mm in mm in kN in mm in mm
120 20 78 80x12 ca. 30
150 25 174 100x12 ca. 30
220 25 390 170x12 ca. 30
250 30 540 190x12 ca. 35
270 30 590 210x14 ca. 35
300 35 780 230x16 ca. 40
350 40 1080 280x18 ca. 45
420 45 1570 330x20 ca. 50
500 45 2350 410x20 ca. 50
600 50 3400 510x25 ca. 55
700 50 4700 595x25 ca. 55
750 50 5500 640x25 ca. 55
1016 55 10300 905x28 ca. 60
190x120 25 230 142x 70x12 ca. 30
300x120 25 320 248x 70x12 ca. 30
380x330 25 1600 330x280x12 ca. 30
440x340 20 2000 400x320x10 ca. 25
450x350 25 2050 398x298x12 ca. 30
490x340 30 2110 430x280x14 ca. 35
500x380 25 2450 450x330x12 ca. 30
500x430 25 2800 450x380x12 ca. 30
598x380 25 3000 548x330x12 ca. 30
598x430 25 3350 548x380x12 ca. 30
750x200 25 1900 702x152x12 ca. 30
750x220 25 2100 702x172x12 ca. 30
800x400 50 3900 700x300x25 ca. 55
1200x300 25 4800 1148x248x12 ca. 30
Subject to alteration

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