Material level indicator sensor |
|||||||
| 申请号 | US38060873 | 申请日 | 1973-07-19 | 公开(公告)号 | US3818159A | 公开(公告)日 | 1974-06-18 |
| 申请人 | WHITLOCK INC; | 发明人 | EVANS A; RANDOLPH C; | ||||
| 摘要 | A level sensing apparatus of the kind comprising a sensing switch actuated by a rotating paddle, with a cam drive connection between the drive motor and the sensing paddle which protects the drive motor from stalling or jamming in either normal or abnormal operation of the level sensing apparatus; the cam drive connection allows continuing unobstructed rotation of the drive motor shaft, when the sensing paddle is blocked, in the event of a failure of the sensing switch. | ||||||
| 权利要求 | 1. A level sensor for sensing accumulation of material, comprising: a drive member; driving means for driving the drive member rotatingly on a main axis; a driven member rotatable about the main axis, aligned with and engageable with said drive member; a sensing paddle connected to the driven member for rotation therewith; a first one of the drive and driven members including an annular cam surface with a dwell portion and a lobe portion; the second one of the drive and driven members including a roller aligned to roll along the cam surface of the first member; at least one of the drive and driven members being movable away from the other member; biasing means urging the drive member and the driven member into engagement with each other so that when the sensing paddle is free to rotate, the roller rolls against the lobe portion of the cam surface and causes the sensing paddle to rotate, and so that when the sensing paddle is blocked by accumulated material, the roller rides onto the lobe portion of the cam surface and causes the drive member and driven member to move away from each other; and sensing switch means actuated between one sensing condition and another whenever said first and second members move away from each other. 2. A level sensor according to claim 1 in which the drive member comprises a rotating drive shaft coaxial with the main axis and a radial drive arm mounted on one end of the drive shaft, with the roller mounted on the drive arm for rotation about a roller axis different from the main axis, and in which the driven member comprises a paddle shaft coaxially aligned with the drive shaft in close proximity thereto, the cam surface comprising an annular surface on a cam member mounted on the end of the paddle shaft adjacent the drive shaft. 3. A level sensor according to claim 2 in which the roller axis extends radially from the main axis, and the roller follows an annular orbital path around the main axis, the cam surface being of circular configuration concentric with the main axis. 4. A level sensor according to claim 2 in which the cam member is longitudinally movable along the main axis and in which the sensing means comprises a sensing switch having a sensing arm projecting into the path of movement of the cam member. 5. A level sensor according to claim 2 in which the drive arm is movable longitudinally of the main axis and in which the sensing switch means comprises a sensing switch projecting into the path of movement of the drive arm. 6. A level sensor according to claim 2 in which the dwell portion of the cam surface is of substantially constant height and the lobe portion includes two gradual sloped segments meeting at a sharply peaked tip, so that the roller cannot rest on the tip. |
||||||
| 说明书全文 | |||||||
QQ群二维码
意见反馈
意见反馈