Sectional key plug for locks

Application filed August 12, 1929. Serial No. 385,279.

My invention relates to improvements m sectional key plugs for pin tumbler locks and the general object of my invention is to provide a key plug of a standardized cross sec5 tional shape which may be made in various different lengths to fit locks of larger or smaller size.

Another object is to provide a sectional key plug which is interchangeable for longer io and shorter locks and which makes it possible to use the same key for the operation of a longer and shorter lock thus making it possible to reduce the number of keys which a person is obliged to carry.

Another object is to provide a key plug of rigid and substantial construction which has an integral head formed at both ends.

A further object is to provide a strong and rugged key plug in which the two parts of 20 the key plug are broached from diametrically opposite sides to form a- key way and in which said two parts are securely riveted together in end to end relation.

Other and more specific objects will be ap²⁵ parent from the following description taken in collection with the accompanying drawing.

In the drawing Fig. 1 is a plan view of a key plug constructed in accordance with my ³⁰ invention showing the two parts of the key plug as they might appear before being riveted together.

Fig. 2 is a fragmentary sectional view on broken line 2—2 of Fig. 1, showing the two ³⁵ parts of the key plug riveted together.

Fig. 3 is a view in cross section substantially on broken line 3—3 of Fig. 1.

Fig. 4 is an end elevation of the key plug on broken line 4—4 of Fig. 1.

⁴⁰ Fig. 5 is an elevation of a key blank of a form adapted to be used in connection with my sectional key plug.

All of the views are drawn on an enlarged scale. Like reference numerals designate ⁴⁵ like parts throughout the several views.

Referring to the drawing 6 and 7 designate the two parts of a sectional key plug of externally cylindrical shape. These two parts 6 and 7 are rigidly secured together in end to ⁵⁰ end relation by forming, on one of said parts, two integral studs or rivets 8 which are inserted into the smaller ends 9 of longitudinally formed holes 10 in the other part and are then expanded and riveted or clinched by the use of a suitable tool inserted from the outer 55 ends of the holes 10. The studs 8 are preferably conically recessed in the end as indicated by dotted lines at 12, in Fig. 1, and the larger and smaller holes 9 and 10 in the other plug part form, at their junction, an in- 60 clined shoulder 13 over which the conically recessed portions of the studs 8 may be expanded.

Screws inserted through the holes 10 and screwed into the plug part 7 could be used for 65 securing the two parts together but.Would be more costly and less desirable and less accurate than the rivets.

Before the two plug parts 6 and 7 are secured together they are broached from oppo- 70 site sides to form a key way. In the positions shown in the drawing the plug section 6, is broached from the top downwardly to form a. part 14 of the keyway and the plug section 7 is similarly broached from the hot- 75 tom.upwardly to form a part 15 of the keyway. When the two plug parts are secured together these two keyway portions register so that a key formed from a blank 16 of the shape shown in Fig. 5 may be readily in- ^s0serted therein. Holes 17 for the reception of the usual tumbler pins (not shown) , are drilled from the broached side downwardly into the plug portion 6 and similar holes 18 are drilled from the unbroached side down- ⁸⁵wardly into the plug portion 7, Smaller ejector holes 17' and ^8' extend on through the unbroached part of the plug portion 6 and through the broached part of the plug _fl0portion 7, to permit the tumbler pins to be punched out when the lock is to be refilled. The plug portion 6 has an integral head 19 and the plug portion 7 has an integral head ,20. When the two portions of the key plug gs are riveted together this constitutes a key plug with an integral head on each end.

The inner encl of the key plug portion 6 is designed to form the key stop 23, against which a properly positioned shoulder 24 on 100

1,892,419 the key 16 may strike when the key is inserted in the key plug.

In assembling a lock employing a key plug of this type a suitable cylindrical hole is pro5 vided in a lock core or key plug housing 21, a fragment only of which is shown in Fig. 1, and the key plug portions 6 and 7 are passed into this hole from opposite ends and are then riveted together thus permanently securing 10 the key plug within the key plug housing and leaving an integral key plug head on both ends.

In the drawing I have shown the key plug portion 6 as having five tumbler pin holes 16 therein and have shown the key plug portion 7 as having three tumbler pin holes. With this arrangement the key plug portion 6 will satisfy the requirements of a five barrel lock by simply riveting a face plate onto the for20 ward encl thereof, the key 16 in this instance will have five notches in the forward end thereof which will operate the lock and the shoulder 24 will abut against the end of the key plug portion 6 and form the stop. If 25 an eight barrel lock is to be made the key plug portion 7 is secured to the end of the key plug portion 6, the key 16 is provided with eight notches and the shoulder 24 engages the end of the plug portion 6 in the 30 same manner. It is thus possible for a person with two locks, one a five barrel and one an eight barrel, to use the same key on both locks. In a similar way the number of tumbler pins may be varied in either one of the 3fi key plug sections to form locks of any desired number of barrels.

The foregoing description and accompanying drawing clearly disclose a preferred embodiment of my invention, but it will be un40 derstood that this disclosure is merely illustrative and that changes in this key plug may be made within the scope and spirit of the following claims.