A portable agricultural tool, such as a harvester, comprising: - a machine body comprising a motor; - a first comb and a second comb connected to the motor by means of a mechanical transmission, which comprises a first connecting rod-crank mechanism configured to move the first comb and a second connecting rod-crank mechanism configured to move the second comb; each connecting rod-crank mechanism (100, 200) comprising a main body (101, 201) fitted to rotate about a respective axis of rotation (X, Y) and a connecting rod (102, 202) having a first end (102a, 202a) hinged to the respective comb (10, 20) and a second end (102b, 202b) hinged to a respective main body (101, 201) in a respective crank pin (103, 203); in use, said main bodies (101, 201) being mutually concordant in rotation; characterised in that the motor is configured to selectively operate in a first drive direction and a second drive direction opposite the first drive direction, and that the main body (101, 201) of the first and/or second connecting rod-crank mechanism (100, 200) defines a sliding path (104, 204) for the respective crank pin (103, 203), the sliding path (103, 203) being delimited by a first end stop (104a, 204a) and a second end stop (104b, 204b) and extending about the respective axis of rotation (X, Y) so that: when the motor operates according to the first drive direction, the crank pin (103, 203) abuts against the first end stop (104a, 204a) so that the two combs (10, 20) mutually take on a first tilting configuration; and when the motor operates according to the second drive direction, the crank pin (103, 203) abuts against the second end stop (104b, 204b) so that the two combs (10, 20) mutually take on a second tilting configuration, which is offset from the first tilting configuration. - a machine body comprising a motor; - a first comb and a second comb connected to the motor by means of a mechanical transmission, which comprises a first connecting rod-crank mechanism configured to move the first comb and a second connecting rod-crank mechanism configured to move the second comb; each connecting rod-crank mechanism (100, 200) comprising a main body (101, 201) fitted to rotate about a respective axis of rotation (X, Y) and a connecting rod (102, 202) having a first end (102a, 202a) hinged to the respective comb (10, 20) and a second end (102b, 202b) hinged to a respective main body (101, 201) in a respective crank pin (103, 203); in use, said main bodies (101, 201) being mutually concordant in rotation; characterised in that the motor is configured to selectively operate in a first drive direction and a second drive direction opposite the first drive direction, and that the main body (101, 201) of the first and/or second connecting rod-crank mechanism (100, 200) defines a sliding path (104, 204) for the respective crank pin (103, 203), the sliding path (103, 203) being delimited by a first end stop (104a, 204a) and a second end stop (104b, 204b) and extending about the respective axis of rotation (X, Y) so that: when the motor operates according to the first drive direction, the crank pin (103, 203) abuts against the first end stop (104a, 204a) so that the two combs (10, 20) mutually take on a first tilting configuration; and when the motor operates according to the second drive direction, the crank pin (103, 203) abuts against the second end stop (104b, 204b) so that the two combs (10, 20) mutually take on a second tilting configuration, which is offset from the first tilting configuration. when the motor operates according to the first drive direction, the crank pin (103, 203) abuts against the first end stop (104a, 204a) so that the two combs (10, 20) mutually take on a first tilting configuration; and when the motor operates according to the second drive direction, the crank pin (103, 203) abuts against the second end stop (104b, 204b) so that the two combs (10, 20) mutually take on a second tilting configuration, which is offset from the first tilting configuration.