An ultrasonic instrument comprising: (a) a body , wherein the body is configured to receive an ultrasonic transducer ; (b) a shaft assembly , wherein the shaft assembly defines a longitudinal axis, wherein the shaft assembly comprises: (i) a hollow sheath , and (ii) an acoustic waveguide , wherein the acoustic waveguide is disposed within the hollow sheath; (c) an ultrasonic blade , wherein the ultrasonic blade is in acoustic communication with the acoustic waveguide; and (d) a clamp arm assembly, wherein the clamp arm assembly comprises: (i) a resilient body member , (ii) a clamp pad at the distal end of the body member, (iii) a first rigid arm extending from the body member and comprising a coupler , wherein the coupler is configured to selectively couple the clamp arm assembly with the shaft assembly and decouple the clamp arm assembly from the shaft assembly, (iv) a second rigid arm extending from the body member and comprising an engaging means configured to engage and bear against the body when the clamp arm assembly is coupled to the shaft assembly, and (v) an actuation member , wherein the actuation member is proximal to the coupler, wherein the actuation member of the clamp arm is configured to be moved toward the body along a path transverse to the longitudinal axis to thereby cause the resilient body member to bow, the engaging means to translate distally along the body, and the clamp pad to move toward the ultrasonic blade. (a) a body , wherein the body is configured to receive an ultrasonic transducer ; (b) a shaft assembly , wherein the shaft assembly defines a longitudinal axis, wherein the shaft assembly comprises: (i) a hollow sheath , and (ii) an acoustic waveguide , wherein the acoustic waveguide is disposed within the hollow sheath; (i) a hollow sheath , and (ii) an acoustic waveguide , wherein the acoustic waveguide is disposed within the hollow sheath; (c) an ultrasonic blade , wherein the ultrasonic blade is in acoustic communication with the acoustic waveguide; and (d) a clamp arm assembly, wherein the clamp arm assembly comprises: (i) a resilient body member , (ii) a clamp pad at the distal end of the body member, (iii) a first rigid arm extending from the body member and comprising a coupler , wherein the coupler is configured to selectively couple the clamp arm assembly with the shaft assembly and decouple the clamp arm assembly from the shaft assembly, (iv) a second rigid arm extending from the body member and comprising an engaging means configured to engage and bear against the body when the clamp arm assembly is coupled to the shaft assembly, and (v) an actuation member , wherein the actuation member is proximal to the coupler, wherein the actuation member of the clamp arm is configured to be moved toward the body along a path transverse to the longitudinal axis to thereby cause the resilient body member to bow, the engaging means to translate distally along the body, and the clamp pad to move toward the ultrasonic blade. (i) a resilient body member , (ii) a clamp pad at the distal end of the body member, (iii) a first rigid arm extending from the body member and comprising a coupler , wherein the coupler is configured to selectively couple the clamp arm assembly with the shaft assembly and decouple the clamp arm assembly from the shaft assembly, (iv) a second rigid arm extending from the body member and comprising an engaging means configured to engage and bear against the body when the clamp arm assembly is coupled to the shaft assembly, and (v) an actuation member , wherein the actuation member is proximal to the coupler, wherein the actuation member of the clamp arm is configured to be moved toward the body along a path transverse to the longitudinal axis to thereby cause the resilient body member to bow, the engaging means to translate distally along the body, and the clamp pad to move toward the ultrasonic blade. <EOS>