Reduced effort manual boom lock

A vehicle having a frame, a ground engaging assembly mounted to the frame for supporting and propelling the vehicle along a surface, a cab coupled to the frame, a backhoe, and a swing frame pivotally mounting the backhoe on the frame about a vertical pivot, the backhoe having a boom rotatably mounted on the swing frame about a horizontal pivot for movement between a transport position and selected working positions, and a hydraulic cylinder operative between the boom and the swing frame for positioning the boom, and a locking system for selectively locking the boom to the swing frame to prevent the boom from rotating about the horizontal pivot in the transport position, comprising:

• an upwardly extending hook mounted on the boom;
• a control lever disposed in the cab;
• a linkage assembly operably coupled to the control lever, wherein movement of the control lever actuates the linkage assembly;
• a boom lock pivotally mounted on the swing frame about a pivot axis, the boom lock including a pair of elongated side members, a flange extending outwardly from the pivot axis and coupling to the linkage assembly, and a transverse member disposed between the pair of side members such that actuation of the linkage assembly lifts the transverse member to engage the upwardly extending hook in the transport position;
• a counterweight body integrally coupled to the boom lock, the center of gravity for the counterweight body being on the opposite side of the pivot axis as the center of gravity for the pair of side members and the transverse member, the counterweight body moving the center of gravity for the boom lock closer to the pivot axis and reducing the force required for lifting the transverse member to engage and disengage the upwardly extending hook on the boom;
• wherein, in the transport position, the distance between the uppermost point of the backhoe and the surface is less than four meters.

A work vehicle for performing an operation, comprising:

• a frame;
• a ground engaging assembly mounted to the frame for supporting and propelling the vehicle along a surface;
• an operator's cab mounted to the frame;
• a swing frame pivotally mounted to the frame about a vertical pivot;
• a backhoe having a boom and a hydraulic cylinder, the boom being rotatably mounted on the swing frame about a horizontal pivot for movement between a transport position and selected working positions, and the hydraulic cylinder operative between the boom and the swing frame for positioning the boom, and
• a locking system for selectively locking the boom to the swing frame to prevent the boom from rotating about the horizontal pivot in the transport position, the locking system comprising:
• an open hook mounted on the boom;
• a control lever disposed in the cab;
• linkage assembly operably coupled to the control lever;
• a spring assembly coupled at one end to the operator's cab and at an opposite end to the linkage assembly;
• a boom lock pivotally mounted on the swing frame about a pivot axis, the boom lock including a pair of elongated side members, a flange extending outwardly from the pivot axis and coupling to the linkage assembly, and a transverse member disposed between the pair of side members such that actuation of the control lever lifts the transverse member to engage the open hook in the transport position;
• and
• a counterweight body integrally coupled to the boom lock, the center of gravity for the counterweight body being on the opposite side of the pivot axis as the center of gravity for the pair of side members and the transverse member, the counterweight body moving the center of gravity for the boom lock closer to the pivot axis and reducing the force required for lifting the transverse member to engage and disengage the open hook;
• wherein, the boom is configured to move between the selected working positions and the transport position, such that in the selected working positions the spring assembly biases the transverse member downwardly;
• further wherein, in the transport position, the distance between an uppermost point of the backhoe and the surface is less than four meters.