Il lu st ra tio n s On e - h a l f Page 517 S i z e CORBIN CYLINDERS MAIJ.-HEARIN(} C’orbiu C'yiiiulei's contain halls of (ioniian Silver to t^ive K'caler ease of operation, and to rcihice tl>e wear by eliininalins friction. In llie Master Keyed ('ylinder, a master ring sur- rounds tlie key phiu', I'lie C’hanf;e Key operates llie key plu|r, and the Master Key ojierates hy lining up the breaks in the pins at the outer line of ihe master ring. "I'liis combines, in a single shell, two cylinders using the same key way for both the (Miange Key and the Master Key Sectional View of No. 253 Cvliiuler C'orbiu Master Keyed Locks are Master Keyed in one set of any tnimber of clianges, all dirterent, with a Master Key to pass, or in any number of sets of any number of changes, all different, with Master Keys to pass eacli set and a (irand Master Key to pass all UNIT IX)CK CYLINDKRS N U M BER 250 250V2 NO. 2 5 0 RIM LOCK CYLINDERS CAST BRONZE N U M BER 251 251 ’ /2 POL IS H ED Each ( ( NO. 2 5 1 ^ DUMMY CYLINDERS CAST BRONZE N U M BER 252 2 5 2 ’/2 NO. 2 5 2 MORTISE LOCK CYLINDERS CAST BRONZE N U M BER 253 I n c h 1 IX 2 5 3 ’/ 2 IX 2 1 IX IX IX 2 Each ( < ( < ( { ( < ( ( i ( i i I I ( ( State length ELECTRIC DOOR OPENERS CAST BRONZE N U M BER F or L ocks 630 Nos. S60B, 561B, 1334B, 1339B, 01339B, S64B, S67B, 0S67B,etc. 631 Nos. 2020, 2038, 2039, 02039, 20S8, 2061, 2062, 2062>^, 2063, 2063X , 2064, 2066, 2067, 02067,etc. NO. 6 3 0 Prefix letters for finish. Description of finishes, page VI ' % Rustless iron PRICE BOOK, Door Openers, One in a Box, with Screws SECTION NO. 6 Each ( POL IS H ED R F IN I S H SR F IN I S H F F IN I S H i POLIS HED R F IN I S H SR F IN I S H F F IN I S H t P OLIS HED Each ‘ ‘ NO. 2 5 2 H Master Keyed Size R F IN IS H SR F IN IS H F FIN I S H t Master Keyed R FIN'ISH SR F IN IS H F F IN IS H t C AST B R O N Z E Polished Each NO. 2505 ^ Master Keyed Sectional View of No. 253)4. Cylinder NO. 2 5 3 ^ . IN . Master Keyed Figure 2. The earliest direct reference to master ring that the author found is in the product catalog from 1905. 36 KEYNOTES MAY 2021 WWW.ALOA.ORG
