Abstract:
An auxiliary lock has a base, an extending shell and a linking arm that, through holes, slots and projections disposed thereon connect adjustably together for lengthening or shortening the assembly while maintaining constant the length of the dead bolt exposed out of a cylinder into a faceplate.

Description:
BACKGROUND OF THE INVENTION 
     Field Of The Invention 
     This invention relates to auxiliary locks of the type having a dead bolt extending through a faceplate for engagement with a locking hole. 
     An auxiliary lock is an extra reinforcing device for safety. When fixing this lock in a door, a long latitudinal groove needs to be cut on the side surface of the door so as to fit the lock in, and a turning hole then is cut in the front surface of the door to fit with the intersecting crossed hole of the lock. The &#34;crossed hole&#34; is a rotatable member having a cross-shaped opening. 
     Nowadays, locks, in order to meet different requirements depending on the structure of a door, are usually manufactured into two sizes--so called 60 mm and 70 mm. therefore manufacturers have to make auxiliary locks of different sizes, retailers are obliged to devote more space for storing them, and besides, buyers will feel puzzled how to select them. 
     SUMMARY OF THE INVENTION 
     The object of this invention is to provide an auxiliary lock wherein the dead bolt is adjustable in its length, by means of making the extending shell move outside of the base, and changing the combining point of the dead bolt with other part so that the distance of the dead bolt exposing out of the faceplate can be kept constant. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described in detail with reference to the accompanying drawings wherein: 
     FIG. 1 is an exploded perspective view of the auxiliary lock of the present invention; 
     FIG. 2 is a cross sectional view take along line 2--2 of 3; 
     FIG. 3 is a cross sectional view take along line 3--3 of 2; 
     FIG. 4 is a cross sectional view take along lines of FIG. 4; 
     FIG. 5 is a cross sectional view take along lines of FIG. 4; 
     FIG. 6 is a cross sectional view take along lines of FIG. 7; 
     FIG. 7 is a view similar to FIG. 5 of the present invention adjusted to the long size. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention includes a base 1, an extending shell 2, assembling plates 3, a dead bolt 4, moving accessories 5 and a fixing plate 6. 
     In a conventional auxiliary lock such as shown in FIG. 1 each of the moving accessories 5 combines with the assembling plates 3, which hook at the base 1. By turning the swing rod 51 of the moving accessories, the linking arm 42 moves making the dead bolt 4 extend out or stay inside of the faceplate 11 of the base 1. 
     The present invention has the same functions as the above known art except that it has the assembling plates 3 assembled at the bottom of the extending shell 2 and that the linking arm 42 combines with the dead bolt 4 to become adjustable in length. 
     The base 1 is combined with a faceplace 11 as a single part of the cylinder. A semicular spring 12 is to be inserted into the cylinder and has two projections 13 at its two sides which will hook with and extend out of the holes 14. The cylinder itself has another hole 15. 
     The extending shell 2 can be put outwards into the cylinder. At the bottom of the extending shell 2 is an assembling opening 21 which is for receiving the hooks 34 of the assembling plates 3 to combine plates 3 with the extending shell. 
     Two key holes 22, 23 at the same level enable the projections 13 of the spring 12 to extend out through the key holes 14 of the base 1; in addition, a slot 24 cut at the other side of the extending shell 2 enables the projection 13 on the other side to extend out through the hole 14 on the other side and extends straight into slot 24 so as to restrict the shell 2 to move along the cylinder in a straight line. 
     The assembling plates 3 and the moving accessories 5 have the same structures as the known art, and their function is based on the following principles. 
     An opening 52 formed in each swinging rod 51 is to fit with a rotating member 60 whose oppositely extending cylindrical projections are disposed in the holes 31 of the assembling plates 3. When the knob is rotated, the swinging rods will be successively motivated to rotate and a pin 53 combined with the swinging rods 51 is able to move along slots 32 in the assembling plates. Then, via a linking plate 54 and a pin 55 the swinging rods 51 and a linking arm 42 are connected together so that the linking arm 42 can be moved by rods 51. 
     The dead bolt 4 receives in a central hole therein a reinforcing rod 41 as shown in FIGS. 1, 2, and is connected with it by an H-shaped, i.e. in cross section, pin 43, which is inserted into the dead bolt 4 after inserting a spring 44 into it. 
     The reinforcing rod 41 has a hole 411 and a straight slot 412 which can receives the end of the linking arm 42 so as to enable the reinforcing rod 41 and the linking arm 42 to be placed into the dead bolt 4 and bolted together with it by inserting the spring 44 and H-shaped pin 43 through a hole 45 in the dead bolt 4. 
     The linking arm 42 has two holes 421 for receiving the H-shaped pin 43, and a slot 422 cut through between the holes 421 which allows the reduced diameter part of the H-shaped pin 43 to pass through it so that the pin 43 can be alternately positioned in either of the holes 421. The connecting hole 423 of the linking arm 42 is connected with the linking plate 54 by the pin 55. A projecting tab 424 of the linking arm 42 engages in the slot 33 of one of the assembling plates 3 to guide the linking arm 42 in a straight line. 
     After all the parts are assembled faceplate 6 restricts outward movement of dead bolt 4 from base 1 and by engagement with shoulders 62 so that part of dead bolt 4 extends out but the dead bolt is retained in the assembly. 
     FIGS. 2, 7 show that the assembly of this new invention is capable of having its length adjusted. The H-shaped pin 43 is locked in the inward hole 421 of the linking arm 42 and urged by the spring 44 to retain its thicker part in the inward hole 421. Then, when the swinging rod 51 is turned clockwise, the linking arm 42 is moved to the right, and, via the pin 43, the dead bolt 4 is successively pulled to move inwardly. 
     FIGS. 4, 5 show how to lengthen the assembly. First, with an unhooking tweezer or a sharpened metal instrument inserted through hole 15 pin 43 is pressed inwardly against spring 44 to enable the thinner part of the pin 43 in ward hole 421 to engage in slot 422 of the linking arm 42, and, at the same time, turn the swinging rods 51 clockwise to make the outward hole 421 fit with pin 43; then remove the pressure on pin 43. Next, as shown in FIGS. 6, 7 through the hole 22 press inwardly the projection 13 of the spring 12 so that the extending shell 2 becomes unlocked and able to be extended outwardly making the projection 13 of the spring 12 to meet with and to go into the hole 23 of the extending shell 2 so as to again fix the shell 2 in the extended position. By means of the above manipulation, the distance between the opening 52 of each swinging rod 51 and the faceplate 11 of the base 1 is lengthened. 
     Of course, if the relatively short length is desired, the reverse order of the above actions can attain it. 
     In summary, via the inward or outward motion of the extending shell 2 along the base cylinder and the connection of the linking arm 42 with the dead bolt 4, the distance between the openings 52 and the faceplate 11 can be altered to become relatively short or long and the length the dead bolt extends out of the faceplate 11 is retained constant so that the present lock can selectively fit with any door.