29(8)If an execution debtor, subsequent to the receipt of the first execution by the sheriff, and before the time for distribution has expired, has executed a mortgage or chattel mortgage, or otherwise charged any portion of his estate, the giving of such mortgage or other security does not have the effect of preventing subsequent execution creditors or other creditors, who have filed their claims as required by this Act, from sharing in the distribution of the money realized by the sheriff, or the sheriff from selling the interest seized under the first execution, but in distributing the money so realized the sheriff shall deduct and retain for the person entitled thereto the amount of any incumbrance so created
pro rata from the amount that would otherwise be payable to the said subsequent creditors, but nothing herein contained has the effect of making valid any chattel mortgage that would otherwise be invalid.