【正文】 lectrical pulses. a shield having an aperture there in concentric to said interference fringes to permit intermittent light pulses to impinge upon said transducer during relative movement of said first and second carriages, means connecting said source to said first carriage driving means, switch means connected to said transducer and operative upon receiving a first given number of pulses there from to disconnect said power source from said first carriage driving means and then to connect said power source to said second carriage driving means and operative upon receiving a second given number of pulses from said transducer to disconnect said power source from said second carriage driving means and then to connect said power source to said first carriage driving means, a grid marking device on said second carriage, and power means actuated upon receiving predetermined ones of said second given number of electrical pulses to energize said grid marking device. 10. Apparatus for producing controlled movement of a member prising first and second carriages movable independently along a fixed path, said member being carried on one of said carriages, driving means for each of said first and second carriages, a power source connectable to each of said driving means, an interferometer including a pair of light reflectors, movement of one of said reflectors relative to the other of said reflectors producing interference fringes, said one reflector being mounted on said first carriage and said other reflector being mounted on said second carriage, a transducer on said second carriage for converting light pulses into electrical pulses, a shield having an aperture therein concentric to said interference fringes to permit intermittent light pulses to impinge upon said transducer during relative movement of said first and second carriages, means connecting said source to said first carriage driving means, switch means connected to said transducer and operative upon receiving a first given number of pulses there from to disconnect said power source from said first carriage driving means and then to connect said power source to said second carriage driving means and operative upon receiving a second given number of pulses from said transducer to disconnect said power source from said second carriage driving means and then to connect said power source to said first carriage driving means. 11. Apparatus for producing controlled movement of a member prising first and second carriages movable independently along a fixed path, said member being carried on one of said carriages, driving means for each of said first and second carriages, an 濟南大學(xué)畢業(yè)設(shè)計 外文資料翻譯 11 interferometer including a pair of light reflectors, movement of one of said reflectors relative to the other of said reflectors producing interference fringes on relative light and dark, said one reflector being mounted on said first carriage and said other reflector being mounted on said second carriage, a transducer for converting such fringes of relative light and dark into electrical pulses upon relative movement between said first and second carriages, means energizing said first carriage driving means, signal means connected to said transducer and operative upon receiving a first given number of electrical pulses for deenergizing said first carriage driving means and then energizing said second carriage driving means, said signal means being further operative upon receiving a second given number of electrical pulses to de energize said second carriage driving means and the n to energize said first carriage driving means. References Cited in the file of this patent UNITED STATES PATENTS 1,455,795 LoganMay 22,1923 1,744,642 KondoJan. 14,1930 1,814,701 IvesJuly 14,1931 2,123,276 EckerlinJuly 12,1938 2,506,141 DrouinMay 2,1950 2,527,338 StamnOct. 24,1950 2,575,367 StrongNov. 20,1951 2,702,393 MertonFeb. 22,1955 745,919 Great BritainMar. 7,1956 OTHER REFERENCES Jenkins and White,”Fundamentals of Optics,”second edition,1950 McGrawHill Book Co.,Inc.,New York,.,pages 247249.(C0py in ) 濟南大學(xué)畢業(yè)設(shè)計 外文資料翻譯 12 濟南大學(xué)畢業(yè)設(shè)計 外文資料翻譯 13 United States Patent Office, Ser. No. 739,123 網(wǎng)格劃 線機 John T Ferris, Houston, Tex. 摘 要 本發(fā)明涉及到網(wǎng)格劃線機，更特別是 ，此設(shè)備為得到準確的橫向劃長度廣泛的空白網(wǎng)格給與保障。 FIG. 2 is a schematic plan view of the ruling machine. Referring now to the drawing, my grid ruling machine prises two carriages l and 2 separately driven along .well machined ways by any conventional drive means such .as pinions 3 and 4, engaging racks 5 and 6 along the machined ways. Each gear 3, 4 is driven by an electric motor 7 and 8, preferably of the servo type so that the velocity, starting and stopping of the carriages l and 2 along the ways, can be maintained under close control. As is well known, the desired velocity control is achieved with a servo motor by modifying the current delivered thereto in response to variations in speed actually delivered thereby Butin any event, the specific drive means employed for the carriages is not material and the motors and gears described are shown by way of illustration only. Other speed control mechanisms such as speed reduce