PROBLEM TO BE SOLVED: To operate a scraper of a sieve by eliminating the need for a motor.SOLUTION: A scraper (30) is provided which reciprocates while coming in sliding contact with a sieve (23). A pair of drive-transfer means (40, 41) attached to a drive link member (37) for reciprocating the scraper (30) is configured to be operated interlocking with drive of a supplying conveying chain (13B). One end of the pair of drive-transfer means (40, 41) is locked in a part becoming point symmetry based on an axis center of an output shaft (44) becoming a rotation center to a driving gear (42) of the supplying conveying chain (13B). A turning shaft (46) is formed in the front end of a supporting member (47) for supporting a chain rail (45) of the supplying conveying chain (13B), and the termination side of the supplying conveying chain (13B) is configured to be openable to the outside. The driving gear (42) of the supplying conveying chain (13B) is detachably configured with respect to the output shaft (44) of the supplying conveying chain (13B).SELECTED DRAWING: Figure 5【課題】シーブのスクレーパを、モータを不要にして作動させる。【解決手段】シーブ（２３）に摺接しながら往復移動するスクレーパ（３０）を設け、スクレーパ（３０）を往復移動させる駆動リンク部材（３７）に取付けた一対の駆動伝達手段（４０、４１）を供給搬送チェン（１３Ｂ）の駆動に連動して作動させる構成とし、一対の駆動伝達手段（４０、４１）の一端を、供給搬送チェン（１３Ｂ）の駆動歯車（４２）に対して、その回転中心となる出力軸（４４）の軸心を基準に点対称となる部位に係止し、供給搬送チェン（１３Ｂ）のチェンレール（４５）を支持する支持部材（４７）の前端に回動軸（４６）を形成して供給搬送チェン（１３Ｂ）の終端側を外側方にオープン可能な構成とし、供給搬送チェン（１３Ｂ）の駆動歯車（４２）を供給搬送チェン（１３Ｂ）の出力軸（４４）に対して継脱自在な構成とする。【選択図】図５
