Fine adjustment thread assembly and processing apparatus

A processing apparatus comprising:

• a holding unit for holding a workpiece on a holding surface thereof;
• a processing unit including a spindle and a processing tool mounted on the spindle;
• a vertically moving mechanism for moving a support case supporting the processing unit thereon in vertical directions perpendicular to the holding surface;
• and
• a processing unit tilt adjusting mechanism for adjusting a tilt of the processing unit with respect to the holding unit, wherein
• the processing unit tilt adjusting mechanism includes a fine adjustment thread assembly for coupling a first part and a second part to each other while keeping the first part and the second part spaced apart from each other, adjusting a distance between the first part and the second part, and detecting a load applied to the second part,
• the fine adjustment thread assembly includes
• first external threads that can be brought into threaded engagement with first internal threads formed in the first part,
• second external threads that are disposed on an extension of an axial direction of the first external threads and axially spaced from the first external threads, that have a thread pitch different from that of the first internal thread, and that are capable of being brought into threaded engagement with second internal threads formed in the second part,
• a joint portion by which the first external threads and the second external threads that are spaced apart from each other are integrally joined to each other, and
• a load sensor housed in the joint portion under a compressive load, and
• the first part includes the support case and the second part includes the processing unit.