Apparatus for detecting and/or controlling tension of a moving web, for example, a filamentary tow utilized in the production of cigarette filters

Apparatus for detecting tension of a moving web, for example, a filamentary tow, said apparatus comprising a sensing roller, and roller support means adapted for supporting said sensing roller generally transverse to a longitudinal path of the moving web such that the web contacts the sensing roller and exerts a reaction force thereagainst in a generally downward direction relative to the movement of said web along said longitudinal path, said reaction force being indicative of the tension of the web, said roller support means including:

• a center support post;
• a bottom support plate which includes a pair of planar deflection arms each rigidly supported at an inner end thereof by means of said center support post and having an unsupported outer end laterally spaced from said supported inner end thereof relative to the longitudinal path of the web, each said deflection arm between said inner and outer ends being defined by (i) leading and trailing edges, relative to the general direction of movement of said web along said longitudinal path, and (ii) planar upper and lower surfaces being joined to said leading and trailing edges and extending from said center support post oppositely relative to the upper and lower surfaces of the other said deflection arm yet parallel to said sensing roller such that said pair of deflection arms are also disposed generally transverse to the longitudinal path of the web, said leading and trailing edges thereby establishing a width dimension of said upper and lower surfaces of each said arm as measured in the general direction of movement of said web along said longitudinal path;
• a pair of journal support means laterally spaced apart from one another relative to the longitudinal path of the web, each said journal support means fixed to and extending upwardly from a respective one of said upper surfaces of said deflection arms at said unsupported outer ends thereof for journally supporting said sensing roller therebetween and for transferring said reaction force to said pair of deflection arms,
• said pair of deflection arms each including means for facilitating resilient generally downward flexion of said deflection arms relative to the direction of movement of said web in response to said reaction force being transferred thereto by said journal support means;
• said roller support means further including first and second pairs of strain gauges each operatively connected to respective said upper and lower surfaces of said pair of deflection arms to detect the extent of said resilient downward flexion thereof to thus provide a signal representative of the tension of the web.

In an apparatus for producing cigarette filters from a tow of crimped, continuous filaments of the type including means for subjecting the tow to longitudinal tension in at least one zone in the path of tow movement, means for releasing the applied longitudinal tension to thereby deregister adjacent crimps of the tow, means for blooming the tow, and means for compacting the tow into a rod-like filter element, the improvement comprising a device to detect longitudinal tension of the tow applied in said at least one zone, said tension detecting device including a sensing roller, and roller support means for supporting said sensing roller generally transverse to a longitudinal path of said tow in said at least one zone such that the tow is in contact with said sensing roller and exerts a reaction force thereagainst which is indicative of the tension of the tow in said at least one zone, said roller support means including:

• a center support post;
• a bottom support plate which includes,
• a pair of planar deflection arms each rigidly supported at an inner end thereof by means of said center support post and having an unsupported outer end laterally spaced from said supported inner end thereof relative to the longitudinal path of the web, each said deflection arm, between said inner and outer ends, being defined by (i) opposing leading and trailing edges, relative to the general direction of movement of said web along said longitudinal path, and (ii) opposing planar upper and lower surfaces, said upper and lower surfaces being joined to said leading and trailing edges and extending from said center support post oppositely relative to the upper and lower surfaces of the other said deflection arm yet parallel to said sensing roller such that said pair of deflection arms are also disposed generally transverse to the longitudinal path of the tow, said leading and trailing edges thereby establishing a width dimension of said upper and lower surfaces of each
• said deflection arm as measured in the general direction of movement of the tow;
• a pair of journal support means laterally spaced apart from one another relative to the longitudinal path of the tow, each said journal support means fixed to and extending upwardly from a respective one of said upper surfaces of said deflection arms at said unsupported outer ends thereof for journally supporting said sensing roller therebetween and for transferring said reaction force to said pair of deflection arms,
• said pair of deflection arms each including means for facilitating resilient generally downward flexion of said deflection arms relative to the direction of movement of said tow in response to said reaction force being transferred thereto by said journal support means;
• said roller support means further including means operatively connected to said pair of deflection arms for detecting the extent of said resilient downward flexion thereof to thus provide a signal representative of the tension of the tow.