1. A braking structure of a ratchet wrench comprising:a wrench head, having an operating portion, a rear end of the wrench head being a head pivoting portion, a peripheral of the head pivoting portion having a plurality of urging grooves;
a wrench handle, a front end of the wrench handle having a handle pivoting portion that is pivotally connected with the head pivoting portion, the handle pivoting portion having a pivoting room, an acting through hole being at a rear end of the pivoting room and extending toward the wrench handle, a positioning device adjacent to a rear end of the handle pivoting portion and having an acting slot extending along an axial direction of the wrench handle and having no connection with the rear end of the pivoting room, an accommodating hole being in the acting slot and being perpendicular to an extension direction of the wrench handle, an urging hole being in the acting slot and located between the rear end of the pivoting room and the accommodating hole, a spring is in the urging hole, an urging ball being on a top of the spring, wherein the accommodating hole has an axial direction perpendicular to and connected with the acting through hole, the accommodating hole has a narrow shape in a plane parallel to a plane of the wrench handle, and a length of the narrow shape extending in the axial direction of the wrench handle is larger than a length of the narrow shape extending in a vertical axial direction of the wrench handle;
an urging device, having an urging rod, wherein a diameter of the urging rod is less than a diameter of the acting through hole and a front end of the urging rod is an urging head that has a rotating slot configured to engagingly receive a flathead screwdriver; and
an operation device, having a pushing member that has an inserting rod, the inserting rod having a positioning through hole that is perpendicular to an axial direction of the inserting rod, wherein the diameter of the inserting rod is less than the length of the accommodating hole and the positioning through hole corresponds to the acting through hole, wherein the positioning through hole is a threaded hole,
wherein the pushing member is disposed in the acting slot, the inserting rod is inserted into the accommodating hole, and the urging rod is through the acting through hole, continuously a threaded section of the urging rod is fixed in the positioning through hole for tight connection of the urging rod and the positioning through hole, and the urging rod is against to one of the urging grooves;
when the pushing member is located ahead, the inserting rod is against to the accommodating hole, therefore the urging head of the urging rod protrudes out of the acting through hole in order to urge the urging grooves, so that the wrench head is positioned so as to proceed rotation operations by means of fitting pieces of the operation portion;
when the wrench head is going to lift and bend, the pushing member is moved backward so as to move the inserting rod and the urging rod, hence, the urging head of the urging rod takes off from one of the urging grooves, so that the angle of lifting and bending the wrench head is controlled, on the contrary, the pushing member is pushed forwardly to let the urging head of the urging rod be against to one of the urging grooves.