to its second position sliding ear portions 402 502 of lock elements 400 500 laterally outward brake surfaces 408 508 are forced against side walls 706 of jamb pocket 702 producing the necessary frictional forces to hold carrier assembly 100 and counterbalance 10 in position when the sash is tilted out for cleaning or removed for servicing when the cam is rotated from its second position to its first position serpentine springs 404 504 retract the extended ear portions 402 502 withdrawing brake surfaces 408 508 from contacting side walls 706 of jamb pocket 702 freeing carrier assembly 100 and counterbalance 10 to move vertically within jamb pocket 702 to provide the desired guidance and support for the sash in the prior art and in commercial practice there are many examples of carriers with lock elements wherein the lock element is manufactured in several configurations with slight differences in dimension to compensate for minor differences in jamb pocket dimensions which may occur between manufacturers or where a different locking friction is desired for major differences in jamb pocket dimensions carrier manufacturers have provided carrier assemblies sized for the particular jamb pocket configuration wherein the carrier bodies have also been sized to the jamb pocket size also in the prior art and in commercial practice carrier assemblies comprising a carrier body a cam and a lock element have been designed such that the cam is positively retained in the assembly by the presence of the lock element carrier assembly 100 represents an improvement over prior art in that it utilizes a single carrier body 200 and cam 300 in all applications only the lock element 400 500 is specific to the particular jamb pocket size thus adapting carrier assembly 100.