Measuring device
A measuring device ( 1; 21; 33 ) for controlling an installation torque of a fastening element ( 4; 32 ) and securable to engagement means ( 3; 35 ) of the fastening element ( 4; 32 ), includes an indicator ( 5; 24 ) for a visual display of the installation torque, a plurality of microcapsules filled with a dispersible color die and supported on the indicator ( 5; 24 ), and a transparent, at least regionwise, covering ( 7.1; 7.2; 22 ) provided on an outer surface of the indicator ( 5; 24 ); and an opening ( 27 ) through which a fastening element ( 4; 32 ) can extend.
1. A measuring device ( 1 ; 21 ; 33 ) for controlling an installation torque of a fastening element ( 4 ; 32 ) and securable to engagement means ( 3 ; 35 ) of the fastening element ( 4 ; 32 ), the measuring device ( 1 ; 21 ; 33 ) comprising indicator means ( 5 ; 24 ) for a visual display of the installation torque; a plurality of microcapsules filled with a dispersible color dye and supported on the indicator means ( 5 ; 24 ); at least partially transparent covering ( 7 . 1 ; 7 . 2 ; 22 ) provided on an outer surface of the indicator means ( 5 ; 24 ) the indicator means ( 5 , 24 ) being visible through a transparent region of the covering; and an opening ( 27 ) through which a fastening element ( 4 ; 32 ) can extend.
2. A measuring device according to claim 1 , wherein the covering ( 22 ) has at least one capillary slot ( 25 . 1 – 25 . 8 ) provided in the transparent region of the covering.
3. A measuring device according to claim 1 , further comprising a washer ( 2 ; 34 ), the indicator means ( 5 ; 24 ) being located between the washer ( 2 ; 34 ) and the covering ( 7 . 1 ; 7 . 2 ; 22 ).
4. A measuring device according to claim 1 , wherein the plurality of microcapsules comprises at least two types of microcapsules filled with different color dyes, and wherein a microcapsule of a first type breaks under a smaller load than a microcapsule of a second type.
5. A measuring device according to claim 1 , wherein the plurality of microcapsules is filed with a fluorescent color dye.
6. A fastening system, comprising a fastening element ( 32 ); and a measuring device ( 33 ) having an opening ( 27 ) through which the fastening element ( 33 ) is extendable, indicator means ( 5 ; 24 ) for a visual display of an installation torque, a plurality of microcapsules filled with a dispersible color die and supported on the indicator means ( 5 ; 24 ), and at least partially transparent covering ( 7 . 1 , 7 . 2 ; 22 ) provided on an outer surface of the indicator means ( 5 ; 24 ), the indicator means being visible through a transparent region of the covering.