cylinder 61 according to the embodiment fig1 and fig1 are sectional views of the internal configuration of the hydraulic cylinder 61 of the present embodiment fig1 illustrates a contracted state of the hydraulic cylinder 61 and fig1 illustrates an extended state of the hydraulic cylinder 61 the hydraulic cylinder 61 of the present embodiment is provided with a cylinder tube 62 a piston rod 63 a piston 64 a guide member 65 a first urging member 66 a second urging member 67 and a hold ring 68 the piston 64 of the hydraulic cylinder 61 of the present embodiment slides inside the cylinder tube 62 due to the supply of hydraulic fluid and the piston rod 63 connected to the piston 64 extends and contracts the extension direction of the piston rod 63 is indicated by arrow a and the direction in which the piston rod 63 is drawn into the cylinder tube 62 also referred to as contraction direction is indicated by arrow b a second end portion 76 of the piston rod 63 forms a connecting portion with a member to be moved by the hydraulic cylinder 61 as illustrated in fig1 the second end portion 76 includes the through hole 76 b the second connecting pin 28 illustrated in fig1 is inserted into the through hole 76 b consequently the second end portion 76 is connected to the second hook 3 illustrated in fig1 as illustrated in fig1 the piston rod 63 is urged in the extension direction a by the first urging member.