Coin lock for bar of supermarket cart
BACKGROUND OF THE INVENTION 
     The present invention relates to a coin lock for stowed articles, particularly articles with a clampable part, such as a bar. The invention is particularly applicable to supermarket carts, or the like. 
     Various types of locks of this type are known, for example, for stowing supermarket carts. Most of these locks have a plastic housing, which can easily be deformed. Further, the system of attachment to the handlebar of the cart does not provide great security. Also, the mechanism of the lock is complicated with respect to the number of its parts and their relationship, so that present locks are not very competitive. These and other characteristics cause present locks to present problems both in manufacture and in use. 
     SUMMARY OF THE INVENTION 
     In order to overcome the drawbacks of the prior art, a coin lock has been devised for stowing an article with a clampable part, like a bar, e.g. a supermarket cart. The lock of the invention has the following advantages over known locks. The part which blocks and frees the closure hook or closure locking plate of the lock, as well as the parts on which the hook or closure locking plate itself slides, the coins and the rods are all seated on surfaces of minimum contact, and they are provided with depressions which decrease the friction. 
     The lock housing, cover and clamps are made of aluminum. The mechanism is simple and does not require skilled labor to make it. 
     The lock is secured to the handlebar of the cart by two part circular clamping shells or parts. Each clamping part includes a pointed protrusion, and the protrusions clamp on the surface of the handlebar of the cart to prevent rotation of the lock on the bar. In order to remove the coin collector or detach it, it is necessary to remove the clamping parts. The attachment of a chain to the lock is effected by a pin. 
     According to the invention, the coin lock for stowing supermarket carts is formed from a prismatic block shaped body having a lateral offset around its perimeter on which the closure cover fits and is fastened by screws. The block has a chain, which is attached by a pin to the block. At its free end, the chain carries the coupling and closure locking plate of the lock. On its upper face, the block has a series of recesses and offsets to position two swing levers which are urged into a lock activated position at all times by the elastic action of individual springs. Each swing lever engages in a respective lock plate which is guided in a respective channel for laterally inward and outward motion as the levers swing. 
     Each swing lever has in the region of its rotation axis a curved edge profile, so that when a coin is introduced through a lateral opening in the block, the coin swings the levers around their respective pivots, which displaces the lock plates laterally. This turned position of the two levers is fixed by two respective bars which are swingable in the direction perpendicular to the plane of the lock plates. The bars each have straight end offsets which fasten the swing levers in their separated apart positions where the levers are turned by the insertion of the coin. The bars are swung under the action of two springs. 
     Opposite the opening into the block where the coin is introduced, the block has another opening into which the closure locking plate, e.g. from an adjacent cart, is introduced. This attaches the two carts together. Upon being introduced into the respective lateral opening, the closure locking plate moves the two lock plates toward the outside, which thereby turn the levers toward the outside. The levers remain positioned separated apart by the turning of the respective bars under spring action. 
     The closure locking plate is secured in the lock body by the lock plates and is freed when those plates are moved outward. The closure locking plate, in turn, presses against a facing end spring, which normally pushes the closure locking plate out of its opening when the lock plates free it to so move. 
     In order more easily to understand the shape and construction of the coin lock of the invention, a practical embodiment is shown below which is merely illustrative and is not limiting. 
     Other objects and features of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the coin lock of the invention. 
     FIG. 2 is a view of the two positions of actuation of the lock of FIG. 1. 
     FIG. 3 is a sectional view through the coupling of the coin lock to a handlebar of a supermarket cart. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings, the coin lock 1 of the invention may be fastened to the handlebar 2 of a supermarket cart (not shown). It may also be clamped to other clampable objects. The lock 1 is formed of a body or block 3 and a cover 4 over the open side of the body. The block 3 has an offset 8 on its perimeter which facilitates the attachment of the cover 4 on the block. 
     Two clamps 5 are attached on the block to mount the lock on the cart by means of screws 6, or the like attachment means. The clamps 5 have a pointed protrusion 7 which presses into the handlebar, as seen in FIG. 3. The lock is intended to remain secured on the handlebar. 
     A chain 9 is fastened on the block. A closure lock plate 10 is firmly secured to the free end of the chain. 
     FIG. 2 shows the mechanism of the coin lock in two positions. The position of rest is indicated in solid line and the position of actuation in dashed line. 
     The block 3 has two oppositely facing lateral openings 11 and 12. A coin 13 is introduced into one opening 11. This causes both swing levers 14 to swing around their pivot pins 15 when the coin presses against the curved edge profiles 16 at the opposing sides of the levers. The curved edge profiles 16 are shaped first such that the insertion of a coin swings the arms of the levers 14 outward and secondly such that with those arms swung outward, the levers hold the inserted coin so as to prevent its removal from the opening 11. This swinging of the levers 14 displaces separate, flat, lock plates 17 toward both outside lateral sides of the block and against the action of the springs 18 which oppose swinging of the levers 14. 
     There are bars 19 which are swingably mounted on respective pins 20 located generally centrally between the levers 14. The bars 19 swing perpendicularly to the swing path of the levers 14 and perpendicularly to the direction of extension and movement of the lock plates 17. Springs at the pins 20 normally urge the bars 19 down toward the levers 14. When the levers 14 have been separated by an inserted coin 13, the bars 19 swing down between the levers to hold them apart and thereby to hold the lock plates 17 apart to free the central closure locking plate 10 for removal from its opening 12 in the block 3. 
     The closure locking plate 10, which is now freed from previous restraint by the lock plates 17, is expelled from the opening 12 by the action of the compression spring 21, which at its other side may be pressed upon by the inserted coin 13. This releases the chain 9 from the neighboring lock and, for example, frees the cart for its use. Reinsertion of the closure locking plate 10 raises the bars 19 against the spring force on them so that when the enlarged head of that plate 10 has passed the lock plates 17 and when the coin 13 is extracted, the levers 14 swing back to their rest position under the influence of their springs 18, and the lock plates 17 return to their positions locked into the recessed neck of the closure locking plate 10. 
     When the cart is returned, in order to recover the coin, the central closure locking plate 10 is introduced into its opening again. This turns the levers 14 in the direction which frees the coin. 
     Although the present invention has been described in relation to a particular embodiment thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.