40 ILCS 5/5-155
A policeman less than age 63 who becomes disabled after the effective date as the result of any cause other than injury incurred in the performance of an act of duty, shall receive ordinary disability benefit during any period or periods of disability exceeding 30 days, for which he does not have a right to receive any part of his salary. Payment of such benefit shall not exceed, in the aggregate, throughout the total service of the policeman, a period equal to one-fourth of the service rendered to the city prior to the time he became disabled, nor more than 5 years. In computing such period of service, the time that the policeman received ordinary disability benefit shall not be included.
When a disabled policeman becomes age 63 or would have been retired by operation of law, whichever is later, the disability benefit shall cease. The policeman, if still disabled, shall thereafter receive such annuity as is provided in accordance with other provisions of this Article.
Ordinary disability benefit shall be 50% of the policeman's salary, as salary is defined in this Article (including the limitation in Section 5-238 if applicable), at the time disability occurs. Until September 1, 1969, before any payment, an amount equal to the sum ordinarily deducted from the policeman's salary for all annuity purposes for the period for which payment of ordinary disability benefit is made shall be deducted from such payment and credited as a deduction from salary for such period. Beginning September 1, 1969, the city shall also contribute all amounts ordinarily contributed by it for annuity purposes for the policeman as if he were in active discharge of his duties. Such sums so credited shall be regarded, for annuity and refund purposes, as sums contributed by the policeman.
40 ILCS 5/5-155