Patent GB-332379-A (GB)
Title: Screw-stud setting machines
IPC: B25B23/147
Filed: 1929-06-28
Abstract: 332,379. Connell, E. L., and Schneider, F. June 28, 1929. Bolts, nuts, and screws, assembling and screwing-up tapping. - A stud-setting machine for screwing studs into automobile engine blocks, crank shafts &c., for setting bolts, nuts, &c. or for threading, tapping, and like operations is provided with an axially-movable tool-spindle 27 driven by an electric motor 3 through a clutch 6 controlled by an electromagnet associated with a relay device, which when a predetermined maximum motor current is reached de-energizes the electromagnet to release the clutch. The machine is mounted on an adjustable, arm 1. The clutch is of the multiple disc friction type, the driven discs being keyed on a hollow clutch member 7 carried by a spindle 8 connected through reducing gearing 9 - - 13 with a spindle 14 which is connected directly with a gear 16 on an upper quill 17 and indirectly through an idler 19 with a, gear 20 on a lower quill 21, the quills being thus rotated in opposite directions. The quills are axially connected by a member 22 having a ball bearing at 23, and carry toothed clutch members 24, 25. respectively, coacting with a double clutch member 26 keyed to the tool-spindle. The quills may be moved downwardly to start an operation by means of a collar 27a operated through a lerver from a handle 30 which also carries a button switch 31. The clutch 7 is operated by a thrust rod 33 either manually or through lever mechanism from an armature 38 actuated by a, solenoid 40. In performing a tapping operation, the clutch 7 is engaged and the tap brought down on to the work, whereupon it is moved axially to engage the clutch teeth 25, 26 for the forward drive. On completion of the operation the handle. 30 is raised, thus raising the quills and engaging the clutch teeth 24, 26 for the reverse movement. For stud setting, the control system shown in Fig. 4 may be employed. The leads of the three phase motor 3 include a switch 51 and the primary winding P of a transformer whose secondary S supplies current to an ammeter A with a movable, pointer 52 coacting with an adjustable contact 53. A control circuit 54 is connected to a solenoid 55 operating the switch 51 and also includes a starting button 56 and stop button 57. In cperation a stud-setting chuck is mounted in the spindle 27 and brought over a stud and the switch 56 depressed to start the motor, the switch 51 being kept in by a switch 58 in a maintaining circuit 59. The switch 31 is then closed, thus closing the circuit of the coil 40 and operating the friction clutch 7. When the stud is driven home the resistance, increases and the increased motor current causes the ammeter arm 52 to move on to the contact 53. This ener. gizes a coil 61 which pulls up the armature 63 and breaks the circuit of the coil 40 thus disengaging the clutch. The ammeter arm then moves back and breaks the coil circuit 61, whereupon the switch 63 closes slowly against a dash pot 64. The delay may be sufficient for the operator to raise the handle 30 to couple the reversing clutch member 24 so that when the clutch 7 is reengaged the chuck is backed off the work. In some cases the handle 30 may be left in its lowered position so that the opening and closing of the switch 63 cause the power to be applied intermittently to the tool spindle. For driving screws or screwing up nuts and bolts reverse rotation of the spindle is not required and the member 26 may then be maintained in permanent engagement with the forward clutch 25 by means of a split spacing collar 71 placed between a fixed collar 70 on the spindle and the quill 17.