Safety device for crossbow

1. A safety device for a crossbow, comprising:

a control box adapted to be connected to a shooting device of the crossbow, the control box including a case, an operation assembly and a pivotal member, the operation assembly located in a rear end of the case, the operation assembly including a hook member, a controller, an engaging member, a resilient member and an assistance spring, the hook member pivotably connected to the case and located in the case, the hook member including a first hook, a second hook and a push portion, the resilient member biased between the push portion and the case, the resilient member pivoting the hook member to release the string, the pivotal member pivotably connected to the case and located in a front end of the case, the pivotal member being biased by a spring, a portion of the pivotal member protruding beyond the case and located corresponding to the operation assembly;

an activation member pivotably connected to the case and located beneath the operation assembly, the activation member having a portion thereof partially protruding beyond the case, the activation member having a stop extending therefrom which is located in the case, the stop located between the operation assembly and a trigger;

a link pivotably connected between the trigger and the portion of the activation member that protrudes beyond the case, and

wherein when the operation assembly is operated to be a string-cocked mode in which no arrow is loaded, a string is pulled toward the case and the hook member is pivoted, the first hook hooks the string, the second hook hooks a first end of the engaging member, a second end of the engaging member is based by the assistance spring and contacts the activation member;

when the controller is moved toward the hook member, the stop of the activation member is restricted by the portion of the pivotal member that protrudes beyond the case so that the activation member cannot be pivoted, and the trigger is restricted by the activation member and cannot be pulled.

2. The crossbow as claimed in claim 1 , wherein the pivotal member includes an end portion, a pivot and a recess, the recess is defined in an underside of the pivotal member and located between the end portion and the pivot, the spring is partially accommodated in the recess and biased between an inner end of the recess and the case so as to protrude the portion of the pivotal member beyond the case, the end portion is located beside the stop to restrict the stop from pivoting when no arrow is loaded.

3. The crossbow as claimed in claim 2 , wherein the case includes a front end, a rear end and a bottom which is formed between the front end and the rear end, a room is formed in the case, a slot is defined through the front end and communicates with the room, two elongate holes are respectively defined through two sides of the case and communicate with the room, an opening is defined through the bottom and communicates with the room, the portion of the activation member protrudes through the opening and is pivotably connected to the link, a separation portion is formed in the ma rear end of the room so as to form a slide path.

4. The crossbow as claimed in claim 3 , wherein the operation assembly includes a hook member, a controller, an engaging member, a resilient member and an assistance spring, the controller is slidably located in the slide path and includes multiple protrusions which are located corresponding to the elongate slots, the hook member is pivotably located in the room and includes a first hook, a second hook and a push portion, the push portion is located above the controller, the resilient member is biased between the push portion and the case, the hook member is pivoted and the first hook protrudes beyond the slot and hooks the string, the engaging member is pivotably located in the room and located below the separation portion, the engaging member includes a first end and a second end, the first end hooks the second hook after the hook member is pivoted, the assistance spring is biased between the second end and the separation portion, when there is no arrow located in the slot, the pivotal member is biased by the spring and protrudes beyond the slot and located close to the stop, the pivotal member restricts the end portion to pivot so that the trigger is restricted from being pulled.

5. The crossbow as claimed in claim 1 , wherein the operation assembly is operated within the case to form a ready-to-shoot mode wherein an arrow is loaded, a distance between the pivotal member and the stop is defined as “e” under the string-cocked mode, a distance between the pivotal member and the stop is defined as “E” under the ready-to-shoot mode, “E” is greater than “e”.

6. The crossbow as claimed in claim 1 , wherein the operation assembly is operated within the case to form a ready-to-shoot mode wherein an arrow is loaded, a distance between the pivotal member and the stop is defined as “e” under the string-cocked mode, a distance between the pivotal member and the stop is defined as “E” under the ready-to-shoot mode, “E” is greater than “e”.

7. The crossbow as claimed in claim 4 , wherein the operation assembly is operated within the case to form a ready-to-shoot mode wherein an arrow is loaded, a distance between the pivotal member and the stop is defined as “e” under the string-cocked mode, a distance between the pivotal member and the stop is defined as “E” under the ready-to-shoot mode, “E” is greater than “e”.