| 摘要 |
921,471. Measuring electrically. CROSS CO. Jan. 10, 1961, No. 1017/61. Class 40 (1). In apparatus for measuring the cutting force of a machine-tool a transducer is mounted between portions of the tool supporting head, the output of the transducer being applied to measuring apparatus including alarm circuits to indicate when the cutting force exceeds a predetermined maximum value. Also described is a circuit which operates an alarm only after the predetermined maximum value has been exceeded a plurality of times in a predetermined time. Transducer mounting.-Fig. 1 shows a drilling- machine head in which a transducer 34 is clamped by the outer of the spindle bearing so as to receive the drilling thrust, preload being applied from plate 22 via the bearing outer. A similar arrangement, Fig. 2 (not shown), is applicable to a lathe head. Fig. 3 shows an alternative arrangement in which the bearing 16 is mounted separately from the transducer 34, again a similar arrangement is described for a lathe, Fig. 4 (not shown). Indicating circuits. Fig. 5 shows one form of circuit in which the output of transducer 35 unbalances valves T1a and T1b to operate contact-making galvo M1 when the transducer output rises to a sufficiently high level due to tool bluntness. Closing of the galvo contacts 160, 162 operates self-holding relay R1 which via contacts R1b operates an alarm device. An alternative arrangement is shown in Fig. 6 and comprises two similar circuits operating relays R2 and R3 which are adjusted to have different operating points, R2 operating, self-holding and igniting neon indicator 41 to give an indication that tool failure is approaching while operation of relay R3 indicates that tool replacement is essential. The contacts R3a, Fig. 6B, of relay R3 may be paralleled with contacts Rna and Rma of relays connected in similar alarm circuits of machine-tools on a production line to operate a self-holding alarm relay R4 to indicate that the production will have to shut down. While the line is shut down inspection of the neons 41 will indicate which tools should be replaced to prevent a further shut down in a relatively short time. In a further embodiment, Figs. 7A and 7B (not shown), a relay counting circuit is utilized so that the alarm circuit is energized only if two or more indications of tool dullness are received within a predetermined time, thus eliminating false indication due to hard spots encountered when machining for example cast iron. Specification 753,916 is referred to. |
