Locking device of a combination lock

Claim 1

An improved locking device of combination lock comprising: a combination lock having toothed combination wheels; a three-way locking means, forming as the shaft of the combination lock and having a pin tumbler cylinder, an outer lock body inserted in tumbler cylinder, and an innermost cylinder connected with tumbler cylinder; a three-extension key corresponding the key hole of said locking means; and a rear locking pin normally poking into the rear portion of said key hole of said locking means to prevent from turning the combination lock for enhancing security; the improvement which comprises: a pin tumbler cylinder and an innermost cylinder of said locking means forming as a shaft of said combination lock; teeth formed on perimeter of each combination wheel which is coaxially formed on the shaft of said combination lock; and a rear locking pin comprises two side extensions, a central extension and a rear extension; the width of said side extensions being slightly smaller than the diameter said key hole of said locking means, the width of said rear extension being larger than the diameter of said key hole, the front portion of said side and central extensions being made acute portion, said rear locking pin, backed by a spring inserted in a recess of said innermost cylinder, poking into the rear portion of said key hole for locking use, whereby said key is inserted into key hole to release said pin tumbler cylinder from said outer lock body for free turning said combination lock for opening the lock.