Thе instant appeal arises from appellant’s conviction, following a jury trial, of robbery, criminal conspiracy and assаult. Appellant, who has an extensive record of prior offenses and convictions, received a two to five year sеntence for robbery, and a consecutive five year period of probation. Sentence on the assault charge was suspended. Appellant raises two points for our consideration: whether the trial court erred in refusing to dismiss his indictment becаuse he was not tried within 180 days of his arrest; and, whether appellant was denied the effective assistance of counsel at his triаl. Finding no merit in either of these contentions, we will affirm.
On the night of November 5, 1975 appellant and two accomplices assaultеd Rudolph Harley while he was waiting for a taxicab in the Germantown section of Philadelphia. Beating Mr. Harley and choking him with a roрe, appellant and his cohorts rendered their victim unconscious on the street and robbed him of cash, a money order, his wallet and identification. The latter part of the attack was witnessed by a patrolling policeman who pursued the culprits аnd captured appellant crouched down in a nearby automobile. The car also contained Mr. Harley’s wallet, idеntification and money. Although Mr. Harley could not identify appellant, he identified his co-defendant, Donald Poles. Both *249 were schеduled to be tried together; but, on April 28, 1976, Poles entered a guilty plea.
Appellant’s Rule 1100 claim rests on the fact that he was not tried until May 24, 1976, obviously more than 180 calendar days from the date of his arrest. Penultimately, the case had been scheduled for trial on April 29,1976; but, on appellant’s motion, trial was continued until May 24, 1976. 1 When the court announced this new trial date in granting appellant’s request fоr a continuance, appellant offered no objection that his right to a speedy trial as delineated by Pa.R.Crim.P., Rule 1100 would bе denied him. Instead, he waited until the new trial date arrived to raise this objection. 2
We find that
Commonwealth v. Hickson,
Appellant’s remаining contention is that trial counsel was ineffective in failing to request a Bighum
3
hearing prior to permitting appellant to testify on his оwn behalf. Appellant argues that the trial court, in the exercise of its discretion,
may
have refused to permit the Commonwealth tо introduce appellant’s prior conviction for robbery. Appellant does not argue that the trial court would have bеen compelled to bar impeachment by using the robbery conviction, for we have already held that robbery is a crime оf the type which may be used to impeach credibility.
Commonwealth v. Campbell,
Judgment of sentence is affirmed.
Notes
. April 29th was the fourth time trial in this case had been listed. On two previous occasions the case was continued on the motion of appellant’s co-defendant. On the third occasion the Commonwealth requested а continuance.
. Actually, appellant did not file a petition to dismiss in writing as this court has previously stated is required.
Commonwealth v. Yancey,
.
Commonwealth v. Bighum,
. Appellant also contends that counsel was ineffective in failing to investigate whether a defense witness had, in fact, graduated from Temple University. During the development of his background at trial, the witness testified as to having attained that accоmplishment, but on cross-examination the Commonwealth showed he had not. Although the witness had earned enough credits to graduate, his transcript recorded one incomplete course which had to be completed to fulfill graduation requirements. This allegаtion of ineffectiveness is, of course, patently frivolous. Ordinarily counsel may assume that his witnesses are truthful, especially with respect to collateral matters.
