have a similar shape the upper frame 21 includes three parts a left side 211 a right side 212 and a front side 213 that is vertical to the left side 211 and the right side 212 one end of the left side 211 is smoothly connected to the upper side 112 of the left wall 11 as shown in fig3 one end of the right side 212 is smoothly connected to the upper side 122 of the right wall 12 a distance between the two sides 211 and 212 of the upper frame 21 is wider than a distance between the left wall 11 and the right wall 12 of the hold part 10 ends of the front side 213 are respectively connected to the left side 211 and the right side 212 smoothly similarly the under frame 22 includes three parts as a left side 221 a right side 222 and a front side 223 an end of the left side 221 is smoothly connected to the lower end of the under side 113 of the left wall 11 as shown in fig3 an end of the right side 222 is smoothly connected to the lower end of the under side 123 of the right wall 12 the protective brace 1 further includes two fasteners for alternatively tying a carry cord the one fastener 214 is fixed on the front side 213 of the upper frame 21 of the first shock absorbing part 20 and the other one fastener 314 is fixed on the front side 313 of the upper frame 31 of the second shock absorbing part 30 the hold part 10 and the first shock absorbing part 20 are smoothly connected together and form.