spring not shown such movement is transmitted by a mechanism including the shaft 20 link 19 sector gear 16 gear 15 bevel gears 14 13 pulley 11 belt 12 and the pulley 10 to rotate the idler 8 in a direction reverse to that at the time of cassette loading therefore the idler holding plate 27 rotates in the direction of the wind mill wheel 9 then the idler 7 comes in contact with the wind mill wheel 9 to rotate the same a sudden movement of the cassette holder 3 can be cushioned by this series of movements also at the time of tape recording or reproduction an increase in the load on the reel stands can be prevented by having the idler 7 apart from the reel stand 5 a mechanism to separate the idler holding plate from the reel stand at a time of recording or reproducing utilizes a link associated with a pinch roller or an association with a loading ring in a video tape recorder etc may be applied fig3 shows another example of a tightening mechanism for a tape recording medium in a recording or reproducing device according to the present invention in the drawing 29 is a cassette holder for holding a cassette and 30 and 31 represent links to support the cassette holder 29 a shaft 32 connects the link 30 to the.