Many problems related to the mechanization involve the draft demanded by machinery and agricultural implements. The measurement of forces in shank implements is generally made by complex and difficult building instruments, as the octagonal ring. Therefore, the aim of this paper is to present the development of a device for measuring the horizontal and vertical forces in shanks of no-till planters by employing off the shelf shear beam force transducers. For this purpose a square shaped frame was designed with two transducers for measuring horizontal forces and another transducer to measure the vertical force. They were mounted with links that restrict the movement of the shank in any direction during its interaction with the soil. A prototype was built and submitted to static laboratory bench testings. One test was made with the application of horizontal load over the shank, another with the application of vertical load and the last one with the application of load with an inclination of 15º to the horizontal to simulate the operating conditions of the shank on the field. The device proved to be robust and it was capable of measuring horizontal forces up to 5,300 N and vertical forces up to 2,000 N, in a linear fashion and with a great correlation coefficient with the applied loads.
force transducer; planter testing; dynamometer
