7  EP 3 800 006 A1 8  of the ball screw 77 by the operation of the servo motor 78 of the cutting amount adjusting means 64. [0024] The moving means 10 and 12 are adapted to move their respective working heads 7 and 11 in such a manner as to cause the working heads 7 and 11 to ap- proach each other or move away from each other by si- multaneously starting the respective grinding operation of the grinding wheels 25 of the working heads 7 and 11 under numerical control (NC). 10 5 adjusted in advance, is moved by the moving means 10 in an X1 direction,whichisone direction ofthe X direction parallel to a direction directed from the one end 8 to the other end 9 of the end face 6 of the glass plate 2 along the end face in the region R1 of the glass plate 2, so as to cause the grinding wheel 25 of the working head 7 to grind the end face in the region R1 of the glass plate 2. During the movement in the X1 direction of the working head 7 by the moving means 10, the working head 11, whose cutting amount (grinding amount) of the end face 6 of the glass plate 2 has been adjusted in advance, is moved by the moving means 12in an X2 direction,which isanotherdirection ofthe X directionparalleltoa direction directed from the other end 9 to the one end 8 of the end face 6 ofthe glassplate 2 along the end face in the regions R2and R3 ofthe glass plate 2,so asto cause the grinding wheel 25 of the working head 11 to grind the end face in the regionR2 ofthe glass plate 2.Meanwhile,the working head 14, whose cutting amount (grinding amount) of the end face 13 of the glass plate 2 has been adjusted in advance, is moved by the moving means 17 in the same way as the moving means10 in the X1 direction fromthe one end 15 of the end face 13 of the glass plate 2 along the end face in theregion R4,so as to causethe grinding wheel 25 of the working head 14 to grind the end face in the region R4 of the glass plate 2. During the movement in the X1 direction of the working head 14 by the moving means 17, the working head 18, whose cutting amount (grinding amount) of the end face 13 of the glass plate 2 has been adjusted in advance, is moved by the moving means 19 in the same way as the moving means 12 in the X2 direction from the other end 16 of the end face 13 of the glass plate 2 along the end face in the regions R5 and R6 of the glass plate 2, so as to cause the grinding wheel 25 of the working head 18 to grind the end face in the region R5 of the glass plate 2. [0025] In the same way as the moving means 10 and 12, the moving means 17 and 19 are adapted to move their respective working heads 14 and 18 in such a man- nerastocause the working heads 14 and 18 to approach each other or move away from each other by simultane- ously starting the respective grinding operation of the grinding wheels 25 ofthe working heads 14 and18 under numerical control. 15 [0026] In addition, the moving means 10, 12, 17, and 19 may be adapted to move their respective working heads 7, 11, 14, and 18 in such a manner as to cause the working heads 7 and 11 and the working heads 14 and 18 to approach each other or move away from each other, respectively, by simultaneously starting the re- spective grinding operation of the grinding wheels 25 of the working heads 7, 11, 14, and 18 under numerical control. 20 25 [0027] Therespective moving speeds inthe X direction of the working heads 7 and 11 may be mutually different oridentical.Further,the respective moving speeds inthe X direction of the working heads 14 and 18 may be mu- tually different or identical. Furthermore, the respective moving speeds in the X direction of the working heads 7, 11, 14, and 18 may be mutually different or identical. 30 35 [0028] On the side of the working heads 7 and 11, the pair of guide rails 62 on that side of the working heads 7 and 11 are used in common for the working heads 7 and 11 and, on the side of the working heads 14 and 18 as well, the pair of guide rails 62 on that side of the working heads 14 and 18 are used in common for the working heads 14 and 18. 40 [0032] As shown in Fig. 5, after the grinding of the re- gion R1 and the region R2 of the glass plate 2 and the region R4 and the region R5 of the glass plate 2, the working head 7 is moved from the working point A of the glass plate 2 in the X2 direction by the moving means 10, and during the movement of the working head 7 in the X2 direction by the moving means 10, the working head 11 is further moved by the moving means 12 in the X2 direction from the vicinity of the central portion on the end face 6 side of the glass plate 2 along the end face in the region R3 of the glass plate 2, so as to cause the grinding wheel 25 of the working head 11 to grind the end face in the region R3 ofthe glassplate2.Meanwhile, the working head 14 is moved from the working point B of the glass plate 2 in the X2 direction by the moving means 17,and during the movementofthe working head 14 in the X2direction by the moving means 17, the work- ing head 18 is further moved by the moving means 19 in the X2 direction from the vicinity of the centralportion on the end face 13 side of the glass plate 2 along the end face in the region R6 of the glass plate 2, so as to cause the grinding wheel25 ofthe working head 18 to grind the [0029] Referring to Figs. 3 to 6, a description will be given of an embodiment of the method of working the glass plate 2 by the glass-plate working apparatus 1 in accordance with the above-described embodiment. 45 50 [0030] As shown in Fig. 3, in the working of both end faces 6 and 13 of the rectangular flat plate-shaped glass plate 2, the glass plate 2 carried in from the upstream side 100 is sucked and fixed by means of the sucker device 50 and is transported onto the supporting table 4 by the transporting means 5, and the unworked glass plate 2 transported by the transporting means5issucked and fixed at the working position for the glass plate 2 by means of the pair of sucker devices 40. 55 [0031] Next, as shown in Figs. 3 and 4, with respect to the glass plate 2 sucked and fixed atthe working position forthe glass plate2 bymeans ofthe pairofsuckerdevices 40, the working head 7, whose cutting amount (grinding amount) of the end face 6 of the glass plate 2 has been 5