Abstract:
The present invention relates to an igniter mechanism for a toy hand grenade which comprises a pull string ignition assembly, a housing that encases the pull string ignition assembly and a stopper that is located in the housing. The igniter mechanism may meet the requirements of safety, reliability and low production cost.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to an ignition apparatus and, more particularly, to an igniter mechanism for a toy hand grenade. 
   Toy hand grenades have been utilized in the prior art for entertainment and amusement. To ignite this type of toy hand grenade, there have been numerous igniters used therein. However, most of these are quite complex and utilize mechanical springs and levers for triggering the ignition. Some of these arrangements utilize a pull-wire having at the opposite end a crimped friction arrangement. This utilizes the draw friction obtained by pulling the wire, coated with a scratch material. The friction between these two materials as the wire is drawn through it causes the ignition of the fuse, which in turn, ignites the pyrotechnic material. 
   For example, in the prior art toy hand grenade which is commercially available, the igniter composition is ignited by means of friction between a metallic pull wire and a metallic cup on both of which a scratch material is coated. As such the metallic members are easy to gather rust so that this type of products must be used before the end of the prescribed period. Also, it is poor in ignition effect and higher in production cost. Moreover, the problems presented by igniting a toy hand grenade are considerably different that ones addressee by the prior art devices. 
   SUMMARY OF THE INVENTION 
   As a result of these disadvantages and in order to meet the requirements of safety, reliability and low production cost, it is an object of the present invention to provide an igniter mechanism for a toy hand grenade. 
   The toy hand grenade according to the present invention consists of a grenade body and a reliable pull-string igniter mechanism. The grenade body can be formed in many different arrangements. For the sake of illustration, this application will be directed to a real hand grenade configuration. Naturally, the igniter mechanism according to the present invention may be used for igniting any firework with fuse. 
   The igniter mechanism in accordance with the present invention is attached to one side of the grenade body. 
   This igniter mechanism comprises: 
   A pull-string ignition assembly that includes a cotton paper, a chemical igniter composition lain on the paper, a fuse train and a pull string; a housing that encases the pull-string ignition assembly; and a stopper that is located in the housing and closes on end of the housing as well as through that the pull string is passed. 
   The pull-string ignition assembly is rolled into a cylindrical form. The housing is a long, hollow, thin cylinder, on one end of which an opening is provided and on another one of which a hole through that the pull string is passed and/or a narrow gap are provided. For the convenience of putting the ignition assembly into the housing, a recess is provided longitudinally on the side surface of the housing. Also, on the outside of the housing a safety lever is located which is integrally formed with a lid cap. The lid cap is fixed at one end of the grenade body. The stopper is placed in the housing and closes one end of the housing. At the center of the stopper a through-hole is formed, through which the pull string is passed. The stopper serves to prevent sparks form being thrown out from the hole of the housing when a pulling force is applied downwardly to the pull-string and friction there between causes sparks to affect the ignition operation of the toy hand grenade. 
   Obviously, the present invention has found a way to solve the problems which have been encountered with the prior art and now provides new and unobvious results that have not been known before. 
   It should be understood that this igniter mechanism of the present invention can be utilized in many different devices and is not limited to a toy hand grenade as shown and illustrated in this application. For example, it may be used for igniting any firework with fuse. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In what follows, the present invention will describe in more detail with reference to the appended drawings: 
       FIG. 1  shows a partially sectional schematic view of a toy hand grenade which incorporates the igniter mechanism of the present invention; and 
       FIG. 2  shows the same toy hand grenade as shown in  FIG. 1  with the lid cup, the safety lever, the housing and partial body removed as well as the pull-string ignition assembly exposed. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Turning now more specifically to the drawings,  FIG. 1  shows a toy hand grenade, which substantially consists of a grenade body  20  and an igniter mechanism  30 . In the grenade body  20 , an elongated tubular body  21  is received which can be formed from paper, plastic, metal or any other suitable materials. In the preferred embodiment, the body  21  can be formed in with a multi-layer configuration wherein the layers are held together with a suitable adhesive. In this way, a relatively strong hollow tubular structure is provided which is at least partially loaded with a suitable burnable pyrotechnic composition or mixture  24 . Such burnable material is sandwiched between two clay layers  25 ,  26 . A central inner passageway  27  can be provided within the clay layer  25  and extended into the pyrotechnic composition or mixture  24 . A safety green fuse  28  can be inserted there into. Also, a primer  29  is combined with the safety fuse  28 . It should be noted that the pyrotechnic mixture needs to be properly compacted and formed during the loading process in order to obtain a continuous and reliable burning of the mixture. 
   The igniter mechanism  30  in accordance with the present invention comprises a pull-string ignition assembly  31 , a housing  32  and a stopper  33 . 
   The pull-string ignition assembly  31  is configurated in a following manner:
     a) a chemical igniter composition such as a suitable phosphorous scratch mix  34  is coated on a cotton paper and one end portion of the pull string is coated with a igniter mixture;   b) a fuse train  35  and a pull string  36  being 150 mm long are placed on the paper, in which one end of the pull string can be crimped in a zigzag configuration or the pull string can be abutted against the fuse train  35 ; and   c) The obtained ignition assembly  31  is then rolled into a cylindrical form having a diameter of 4 mm.   

   The one end of fuse train  35  is connected in a burnable manner to the fuse  28 . A pulling ring  37  is held at the end of the pull string  36  to be pulled. This allows the pull string  36  to be easily withdrawn. 
   The housing  32  is a long, hollow, thin cylinder on one end of which an opening is provided and another end of which has a hole and/or a narrow gap. The fuse train  35  is connected through the opening to the fuse  28 . The pull string is extended through the hole or the gap to outside of the housing. For the convenience of placing the pull-string ignition assembly  31  into the housing  32 , a guide recess  40  is provided on the housing  32  in a direction parallel to the axis thereof and the narrow gap is communicated with the recess and the hole. The guide recess  40  has a width which is slightly more than the diameter of the pull string ignition assembly  31  so that the assembly  31  is easy to be introduced into the housing through the guide recess  40 . 
   A novel feature of the present invention is the addition of a stopper  33  rested on one end of the housing  32 . The stopper  33  is made of elastic material, such as rubber. This stopper  33  is approximately 5 mm in diameter and approximately 4 mm high. A through-hole is formed at the center of the stopper. The pull string  36  passes through the central aperture provided therein and the hole or the gap provided in the housing  32  to outside of the housing  32 . The purpose of the stopper  33  is to automatically and simultaneously close the hole on the housing when withdrawing the pull-string to ignite the toy hand grenade and to prevent sparks from being thrown out from the hole or the gap. Thus, in use, the toy hand grenade of the present invention can prevent sparks, flame and gases from traveling down through the hole to endanger the user. 
   Further, a safety lever  38  is held outside of the housing  32 , which is integrally formed with a lid cap  39 . The lid cap is held on top end of the grenade body  20  in a snap-on manner. Thus, the lid cap with the safety lever  38  is able to be easily released or mounted. Also, an opening is provided on the central portion of the lid cap, on which a label is attached. In order to keep the pulling ring  37  on the lever  38 , a recess is formed on the safety lever  38  to receive the pull string  36 , an opening of which is provided on one side of the lever. The recess is extended from the opening in a transverse direction and then in a longitudinal direction so that the recess is in the form of inverted “L”. 
   Referring now to  FIG. 2 , when it is desired to ignite the toy hand grenade, the lid cap  39  with the safety lever  38  may be kept. The pulling ring  37  is then grasped and pulled sharply downward and away from the end of the housing  32 . The motion causes the friction compound to provide a flash. This flash ignites the fuse  35  causing an intense flame to be generated. At this time, sparks, flame and gases to endanger the user can be prevented from passing through the hole or the gap on the housing  32  as there is a stopper  33  in the housing  32 . For the purpose of safety, the 3 cm pull string needs to be kept in the housing. Under this circumstance, 3 cm motion, when pulling the ring downward, does not cause the friction and the flash is not provided. 
   Once withdrawing the pull string, this motion will cause the fuse train  35  to be burned which in turn burns the predetermined length of safety green fuse  28  until the pyrotechnic composition included therein is detonated. Also, the label on the lid cap is burned through. Usually, the toy hand grenade has to be immediately thrown down upon an open place beyond 10 meters. It will take about 3 to 9 seconds from withdrawing the pull string to detonating the toy hand grenade. 
   Although an igniter mechanism for toy hand grenade has been shown and described in the application, it should be understood that this invention is not to be limited to the exact form disclosed, and changes in detail and construction of the invention may be made without departing from the spirit thereof.