| 摘要 |
<p>779,306. Microtomes. SITTE, H. May 27, 1955 [June 1, 1954], No. 15333/55. Class 97(1). The specimen 6 is secured to the end of a flexible rod 1 of good thermal conductivity embedded in a block 2 of large thermal capacity, means being provided for heating the block, the end of the rod being moved in a closed path so that the specimen is moved past the cutting edge 8 once in each cycle. The rod 1 may be replaced by a tube forming part of a system by which liquid is circulated also through a passage in the block 2, to assist heat transfer, by natural convection or by a pump. The block may be heated by an electrical element in bores 15 or in a cavity in the face of the block. A thermometer may be provided or the current supply may be controlled automatically by 'a bimetallic element. Cooling water, or liquified gas may be circulated through a bore 14 to cool the block in preparation for a fresh series of cuts. In the form shown the end of the rod 1 is actuated by a hand or motor driven crank 36. The crankpin is coupled by a bearing 32 to one end of a bent rigid lever 30, 31, the other end of which is coupled by a bearing 34 to the end of the rod 1. An intermediate point of the lever is coupled by a bearing 33 to a pin 40 secured to one end of a lever 39 carried on a bearing 41. To take account of the fact that the movements of the lever system are not limited to a plane the bearings 32, 34, 41 are self aligning. Alternatively the lever 31 may be a flexible strip while the levers 30 and 39 move in a plane. The lever 39 may then also be replaced by a flexible strip rigidly secured to the lever 30 and to the framework.</p> |
