Patent GB-803694-A (GB)
Title: Improvements in or relating to x-ray devices
IPC: G03B42/02
Filed: 1957-03-06
Abstract: 803,694. X-ray apparatus. PHILIPS ELECTRICAL INDUSTRIES, Ltd. March 6, 1957 [March 6, 1956], No. 7422/57. Class 98(1) In a device for serial radiography, the plate or film holder is moved after each exposure to a rest position and thereafter into a new exposure position by mechanism consisting of two parts; the first of which rotates about a shaft and drives the holder through the second part, which is coupled to the holder and rotates about a pivot on the first part of a submultiple of the speed of the first part. As shown in Figs. 1, 2, the mechanism is actuated by a handle 2, which rotates a gear wheel 5 meshing with a gear wheel 6 mounted on a hollow shaft 7, which extends through a housing wall 8 and carries arm 9 for driving the film or plate holder 1. A link 10 connects the holder 1 to a pin 12 on a slide 13 movable in a slot 14 in arm 9. A short arm 15, mounted on a shaft 16 rotatably mounted in shaft 7, is linked by a rod 18 to the slide 13. A gear wheel 19 on shaft 16 is connected, through gear wheels 20, 21 connected to each other and axially movable on a shaft 22, to the gear 6 on shaft 7. Since the diameter of wheel 21 is twice that of wheel 20, the arm 15 is driven in the same direction as arm 9, but at half the speed. By means of a lever 24, wheels 20, 21 may be slid along shaft 22 until wheel 20 is disengaged and wheel 21 engages both wheel 6 and a gear wheel 28 of the same diameter fixed to gear wheel 19. Arms 9 and 15 then rotate at the same speed. Serial radiography is effected as follows: In a rest position of holder 1, arm 9 extends to the right in Fig. 2, with arm 15 extending upwards at right-angles. The arms are rotated anti-clockwise until arm 9 extends to the left; arm 15 moving at half the speed turns through a rightangle and thus extends in the same direction as arm 9. The holder is then in an extreme left position. Further rotation brings arm 9 to its previous position, with arm 15 extending downwards at rightangles; this brings holder 1 to rest position again. Lever 24 is operated to make the levers rotate at the same rate, and they are turned through 180 degrees to bring the holder to an intermediate operative position. A further rotation of 180 degrees brings holder 1 to rest position again, and lever 24 is returned to its initial position, so that when lever 9 is again turned through 180 degrees, lever 15 turns through a right-angle and extends in the opposite direction, so that the holder 1 takes up an extreme right position. If only two operative positions are required, lever 24 is not operated. The holder may be displaced at right-angles to the direction of movement referred to above so that 4 or 6 positions may be obtained. In another embodiment, Fig. 5, the holder 1 is connected to a rod 34 pivoted to a rod 32 fixed to a gear wheel 30 mounted on a toothed disc 29. Wheel 30 is connected through an idler 37 mounted on the disc to a gear wheel 35. Means are provided whereby wheel 35 is either held stationary or moves with disc 29, so that, when disc 29 is driven by a motor 39, the wheel 30 may rotate either at the same speed as disc 29 or twice its speed. Operation is similar to that described with respect to Figs. 1 and 2. The holder 1 is slidable along the transverse sides 52, 53 of a frame which is movable in a frame 42 supporting shielding material having an exposure aperture 57.