Patent ID: 7891672

Claim:
A chuck for releasably securing an article comprising: a receiving portion comprising a receiving bore having a longitudinal axis (L) and a receiving bore surface; a clamping sleeve accommodated in the receiving bore and being rotatable between a releasing position and a securing position, the clamping sleeve comprising a contoured clamping surface having at least one clamping segment, the at least one clamping segment comprising a first ramp between a trough and a crest, and a second ramp between the crest and a depression, wherein the trough, crest and depression are respectively, at a trough distance D T , a crest distance D C and a depression distance D D , from the longitudinal axis (L), wherein D T <D D <D C ; and one or more rollers associated with said at least one clamping segment, the one or more rollers being accommodated between the receiving bore surface and the contoured clamping surface, wherein: when the clamping sleeve is in the securing position, a first roller of said one or more rollers is accommodated in the depression, and at least one of said one or more rollers applies a radially inwardly directed force against the contoured clamping surface; and when the clamping sleeve is in the releasing position, said first roller is not accommodated in the depression.