Watch band with adjustable fit

Abstract

Watch bands can be provided with an ability to dynamically adjust the fit of a watch against a wrist of a user. One or more of a variety of tensioners can be provided with a shape-memory alloy that responds to a stimulus to adjust a fit of the band. Such stimulus can be from user or actively applied by the watch.

What is claimed is: 
     
         1 . A watch band comprising:
 a first end portion configured to releasably connect to a first side of a watch housing;   a first tensioner comprising a shape-memory alloy configured to controllably adjust a length of the first end portion;   a second end portion configured to releasably connect to a second side of the watch housing;   a second tensioner comprising the shape-memory alloy configured to controllably adjust a length of the second end portion; and   a middle portion between the first end portion and the second end portion, the middle portion being stretchable to adjust a length of the watch band.   
     
     
         2 . The watch band of  claim 1 , further comprising a cover extending continuously to surround the first tensioner and the second tensioner and defining the middle portion. 
     
     
         3 . The watch band of  claim 2 , wherein:
 the first end portion further comprises a first lug and a first anchor each having a fixed position with respect to corresponding first portions of the cover, wherein the first tensioner adjustably connects the first lug to the first anchor; and   the second end portion further comprises a second lug and a second anchor each having a fixed position with respect to corresponding second portions of the cover, wherein the second tensioner adjustably connects the second lug to the second anchor.   
     
     
         4 . The watch band of  claim 3 , wherein:
 the first end portion further comprises multiple additional first tensioners of the shape-memory alloy connecting the first lug to the first anchor; and   the second end portion further comprises multiple additional second tensioners of the shape-memory alloy connecting the second lug to the second anchor.   
     
     
         5 . The watch band of  claim 3 , wherein a first portion of the cover is interposed between the first anchor and the first lug, and a second portion of the cover is interposed between the second anchor and the second lug. 
     
     
         6 . The watch band of  claim 2 , wherein the cover comprises an elastic polymer. 
     
     
         7 . The watch band of  claim 1 , wherein the first tensioner and the second tensioner are configured to respond to a stimulus to adjust a fastening force of the watch band on a wrist of a user. 
     
     
         8 . The watch band of  claim 1 , wherein:
 the first tensioner is configured to receive a first electrical current to controllably adjust the length of the first end portion by generating heat within the first tensioner; and   the second tensioner is configured to receive a second electrical current to controllably adjust the length of the second end portion by generating heat within the second tensioner.   
     
     
         9 . A watch band comprising:
 a cover defining:
 a first end portion configured to releasably connect to a first side of a watch housing; 
 a second end portion configured to releasably connect to a second side of the watch housing; 
 a first edge extending from the first end portion to the second end portion; and 
 a second edge extending from the first end portion to the second end portion; and 
   a tensioner extending within the cover from the first end portion to the second end portion and along a path that extends alternatingly towards each of the first edge and the second edge, the tensioner comprising a shape-memory alloy configured to controllably adjust a length of the watch band.   
     
     
         10 . The watch band of  claim 9 , further comprising a first lug within the first end portion and a second lug within the second end portion, wherein the tensioner is connected to the first lug and the second lug. 
     
     
         11 . The watch band of  claim 9 , wherein:
 the tensioner is a first tensioner;   the path is a first path; and   the watch band further comprises a second tensioner extending within the cover from the first end portion to the second end portion and along a second path that extends alternatingly towards each of the first edge and the second edge, the second tensioner comprising the shape-memory alloy configured to controllably adjust the length of the watch band.   
     
     
         12 . The watch band of  claim 11 , wherein the first tensioner and the second tensioner cross each other multiple times along the length of the watch band. 
     
     
         13 . The watch band of  claim 9 , wherein the cover comprises an elastic polymer. 
     
     
         14 . A watch band comprising:
 a cover;   an anchor within the cover; and   a tensioning assembly within the cover and comprising:
 a lever configured to rotate about a pivot; 
 a tensioner comprising a shape-memory alloy; and 
 a cable extending from the lever to the anchor, wherein the tensioner is operable to controllably actuate the lever and adjust a length of the watch band. 
   
     
     
         15 . The watch band of  claim 14 , wherein:
 the tensioner is a first tensioner;   the tensioning assembly further comprises:
 a pawl configured to engage the lever at a rotational orientation of the lever; and 
 a second tensioner comprising the shape-memory alloy configured to controllably actuate the pawl to release the lever. 
   
     
     
         16 . The watch band of  claim 14 , wherein:
 the lever is a first lever;   the pivot is a first pivot;   the tensioning assembly further comprises a second lever configured to rotate about a second pivot;   the tensioner is further configured to actuate the second lever; and   the cable further extends from the second lever to the anchor.   
     
     
         17 . The watch band of  claim 16 , wherein:
 the tensioner is a first tensioner;   the tensioning assembly further comprises:
 a first pawl configured to engage the first lever at a rotational orientation of the first lever; 
 a second tensioner comprising the shape-memory alloy configured to controllably actuate the first pawl to release the first lever; 
 a second pawl configured to engage the second lever at a rotational orientation of the second lever; and 
 a third tensioner comprising the shape-memory alloy configured to controllably actuate the second pawl to release the second lever. 
   
     
     
         18 . The watch band of  claim 14 , wherein:
 the anchor is a first anchor;   the tensioning assembly is a first tensioning assembly;   the tensioner is a first tensioner; and   the cover defines:
 a first end portion configured to releasably connect to a first side of a watch housing and containing the first tensioning assembly, wherein the first tensioner is operable to adjust the length of the watch band by adjusting a length of the first end portion; 
 a second end portion configured to releasably connect to a second side of the watch housing and containing a second tensioning assembly configured to controllably adjust a length of the second end portion; and 
 a middle portion between the first end portion and the second end portion, the middle portion being stretchable to adjust a length of the watch band. 
   
     
     
         19 . The watch band of  claim 14 , wherein the cover comprises an elastic polymer. 
     
     
         20 . The watch band of  claim 14 , wherein a portion of the cover is interposed between the anchor and the tensioning assembly.