Lock Assembly

1. Field of the Invention

This invention relates to a locking assembly and more particularly to a locking assembly for joining ends of a security device such as a chain.

2. Description of the Prior Art

In the railroad industry, tampering with rail line switches has become a serious problem. It is desirable that the switches be locked in position with a lock assembly which can be conveniently operated by keys of simple manufacture.

Exposure to rain, snow, and ice renders many types of prior art assemblies unsuitable for the above application. If ice collects within the lock assembly, the lock may become inoperable. Furthermore, lock assemblies of the prior art which are protected from the elements are both costly and difficult to operate.

It is an object of this invention to provide a lock assembly which is simple to manufacture, inexpensive, easy to operate, and is protected from contamination by snow, dirt or ice.

It is another object of this invention to provide a lock assembly in which a key used with the assembly may be easily coded to provide a large selection of keys.

It is a further object of this invention to provide a lock assembly which can be unlocked by use of only one hand and wherein a locking cap portion of the locking assembly remains on the key after unlocking.

According to the invention, the lock assembly has a locking post and a locking cap receivable over an end of the post. The other end of the locking post is secured to an end of a security device such as a chain. The post is provided with a longitudinal bore and at least one rib transverse to the longitudinal axis and near the end of the post. At least one longitudinal slot is also provided which intersects at least one rib.

A key aperture in the locking cap is provided together with locking means positioned in the locking cap which are spring biased so as to engage the rib of the locking post when the cap is received over the end of the locking post. To unlock the assembly, a key having a shank portion with a release means thereon is inserted into the locking cap. The release means moves the locking means away from engagement with at least one rib by action through the locking post longitudinal slot.

FIG. 1 is a plan view of the key used to unlock the locking assembly of this invention;

FIG. 2 is a cross-sectional view of the locking assembly of this invention;

FIG. 3 is a cross-sectional view of the locking assembly of FIG. 2 with the key of FIG. 1 inserted;

FIG. 4A is a plan view of a locking post of the locking assembly of FIG. 2;

FIG. 4B is a fragmentary side view of a securing portion of the locking post of FIG. 4A;

FIG. 5 is a plan view of a cap body of a locking cap of the locking assembly of FIG. 2;

FIG. 6 is a cross-sectional view taken along line IV--IV of FIG. 2;

FIG. 7 is a plan view of a key selector plate in the locking cap of FIG. 2;

FIG. 8A is a cross-sectional view taken along line VIII--VIII of the key of FIG. 1; and

FIGS. 8B and 8C are alternate embodiments of FIG. 8A.

A key generally illustrated at 10 and a lock generally illustrated at 11 in FIGS. 1 and 2 comprise the lock assembly of this invention. A security device such as a chain 12 has a link 26 connected to a locking post 21 and a link 44 connected to a locking cap 22 received over an end of the locking post 21. The portion 13 of this chain between the links 26 and 44 may be used to secure a railroad switch, for example. A tiedown portion 14 of the chain may be staked to a railroad tie to prevent unauthorized removal of the lock assembly.

The lock key 10 shown in FIG. 1 has a finger grip 15 with an aperture 16 therein. A shank 17 of the key has a stopper 18 and radially spaced fins 19a,b,c, surrounding the shank 17 below the stopper 18. A beveled edge 9a,b,c, is provided on each of the fins. A guide member or pin 20 protrudes from an end of the shank 17.

As shown in FIG. 2, the locking cap 22 is received and locked to an end of the locking post 21. Referring to FIGS. 2, 3, 4A and 4B, a securing portion 23 can be seen at one end of the locking post 21. This securing portion has upper and lower surfaces 25a,b with a retaining pin 24 mounted therebetween. The chain link 26 is retained by the pin 24 in such a position that a central, longitudinal bore 28 through a post member 27 of the locking post has its one end enclosed by an end portion of the chain link 26. An injector spring 29 is provided in the bore 28 such that an end 29a of the spring is biased against the link 26. The other end 29b of the spring 29 is biased against an ejector pin or piston 30 movable within the bore 28. A narrowed portion 31 within the bore 28 serves as a stop against which a shoulder 32 on the ejector pin 30 is biased by the action of the spring 29. A protruding portion 33 at the end of the ejector pin 30 centers the end 29b of the spring 29 against the ejector pin 30. At the other end of the ejector pin 30 an aperture 34 is provided for mating with the guide member 20 of the lock key 10 shown in FIG. 1.

FIG. 3 illustrates the position of the ejector pin during a compressed position 30' when the key 10 is inserted in the lock.

As shown most clearly in FIG. 4A, three longitudinal slots 35a,b,c are arranged around the post member 27 at the key insertion end of the locking post 21. These slots correspond in position to fins 19a,b,c of key 10. These slots extend as far as the narrowed portion 31 within the bore 28 of the post member 27.

Annular recesses 39a,b,c,d at the key insertion end of the post member 27 form circular ribs 36a,b,c. The periphery of these ribs is chamfered at 37a,b,c together with a chamfered edge 37d adjacent the recess 39d. A leading chamfered edge 38 at the front of the key insertion end of the post member 27 is also provided.

Referring now to FIGS. 2 and 5, the locking cap 22 is illustrated having a cup-shaped circular body portion 40. A key entry aperture 41 is provided at a key insertion end of the locking cap. A protruding lobe 42 having an aperture 43 connects to a chain link 44. A key selector plate 45 is mounted in the cap body 40 adjacent the key entry aperture 41. This key selector plate is shown isolated in FIG. 7. An aperture 46 together with slots 46a,b,c is provided in the key selector plate 45 such that they correspond to the positioning of fins 19a,b,c on key 10 and slots 35a,b,c in post member 27.

As shown in FIGS. 2 and 6, spring bias locking rings 47a,b,c,d are positioned within the body portion 40 of the locking cap 22 by a locator member 48. These locking rings are further held in position by housing or spacing members 49a,b,c having annular grooves within which the locking rings are seated. A cover member 50 retains the housing members and locator member within the body portion 40 when a circular flange 51 is bent over against the cover member 50. The locking rings 47a,b,c,d may be either flat or round. Springs 52a,b,c,d bias these locking rings in an offset manner. In place of springs 52a,b,c,d split rings with a built-in tension may also be employed. Aperture 53 (see FIG. 6) formed within the center of the locking rings is preferably larger than the diameter of the recesses 39a,b,c, and approximately the same dimension as the diameter of the ribs 36a,b,c.

Chamfered edges 56a,b,c,d illustrated most clearly in FIG. 3 may be formed on the outer peripheral edges of the locking rings 47a,b,c,d. Such edges may be provided in combination with chamfered edges 37a,b,c,d on the post ribs 36a,b,c or may be employed in place of chamfered edges on the post ribs. This permits locking without a key by simply pushing the locking cap onto the locking post.

As shown in FIGS. 8A,B,C, coding of the keys 10 is accomplished by various placements of the fins 19a,b,c about the shank 17. As illustrated, fewer or more fins may be employed at various angles to obtain different codings. The 90.degree. placement of fins 54a,b,c,d in FIG. 8B or the offset of one fin 55d as compared to other fins 55a,b,c as shown in FIG. 8C may be employed. It should be noted that the slots in the key selector plate 45 and slots in the post member 27 must match the fin placement of the key 10.

To lock the assembly, a locking cap 22 is inserted over the end of the locking post 21. The leading chamfered edge 38 and chamfered edges 37a,b,c on ribs 36a,b,c or the chamfered edges 56a,b,c,d on the locking rings automatically center the locking rings 47a,b,c,d. When the end of the post 21 abuts against the key selector plate 45, the rings are then biased into the annular recesses 39a,b,c,d to retain the locking cap 22 in place.

To unlock the assembly, key 10 is inserted through the key selector plate 45. Beveled edges 9a,b,c of the fins 19a,b,c center the locking rings 47a,b,c,d to release the cap 22.

The ejector pin or piston 30 retracts as the key is forced inwardly during unlocking. This pin has multiple functions. The pin protects the system against dirt or ice and also deters picking of the lock. Furthermore, the piston 30 permits one hand unlocking of the assembly since once the key is inserted, the ejector pin 30 then forces the key out of the bore 28 while the locking cap 22 remains on the end of the key due to the biasing action of the springs 52a,b,c,d.

Although as few as one locking ring may be employed, the more locking rings that are provided the greater the integrity of the assembly. Each ring preferably grips the ribs of the locking post through an angle of 180.degree., although smaller gripping angles down to 90.degree. are acceptable. If two rings are provided, with each gripping through an angle of 180.degree., a 360.degree. surface retention angle may be obtained.

If a key selector plate 45 is loosely mounted, it can be rotated to cover the slots 35a,b,c of the post member 27 and thus further inhibit entry of dirt. If the plate 45 is securely mounted, the cap 22 may be rotated to cover slots 35a,b,c. In either event, before unlocking, the slots of the key selector plate must be aligned with the slots in the locking post.

It should be appreciated that with the locking assembly of this invention, a variety of key configurations can be obtained by changing the angles and number of fins on the key.

Cap 22 may be manufactured either by press fitting assembly or machining as a one piece assembly.

A less expensive system can be obtained by eliminating the center piston pin 30 although such a system will not have the automatic locking features or the weather protection inherent in the assembly which includes the piston pin 30.

Although various minor modifications may be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent warranted hereon, all such embodiments as reasonably and properly come within the scope of my contribution to the art.