Patent GB-157965-A (GB)
Title: Improvements in driving mechanism for metal-planing machines
IPC: F16H48/14
Filed: 1921-01-10
Abstract: 157,965. Jung, K. T. F. May 9, 1917, [Convention date]. Planing.-Driving mechanism for planing- machine tables comprises means whereby the table is accelerated to the normal cutting or return speed during the first portion of the stroke and retarded during the latter portion, thus permitting the tool to enter and leave the work without shock, and rendering it possible to use high cutting and return speeds. Fig. 3 shows the velocity diagram produced by one form of the invention. AD represents the stroke of the table and v, v<1> the cutting and return speeds respectively. The tool enters the work near the point A and leaves i @near the point D. A driving-shaft 17 having a fly-wheel 2 carries loose spur-wheels 3, 5, 8 which may be respectively locked on the shaft by clutches K<2>, K<1>, K. The rack 15 on the table is driven at the normal cutting speed from the wheel 5 through spur gearing 6, 7, 12, 13, 14. The normal return speed is obtained from the wheel 3 through gearing 4, 12, 13, 14. The wheel 8 engages a spur wheel 9 mounted on a shaft 20 and carrying a pin 16 engaging a slot in a toothed sector 10 pivoted at 21 and engaging a wheel 11 on the shaft 18. During the portion AB of the cutting stroke, the clutch K is engaged and the pin 16 moves from I to II, Fig. 4, thus driving the table through the sector 10 and gears 11, 12, 13, 14 with an acceleration as shown in Fig, 3. The clutch K<1> is then engaged to give the normal cutting speed, and at the point C the clutch K is re-engaged while the pin 16 moves from II to III to retard the table and from III to IV to accelerate the table to a higher return speed. The clutch K<2> is then engaged to give the uniform return speed from E to F, and at the latter point the clutch K is again engaged to retard the table during the portion FA of the stroke while the pin 16 moves from IV to I. The engagements of the clutch K at the points C and F may be conveniently effected by dogs on the table and the engagements at points B, E by dogs on the wheel 9 or sector 10. In a modification, Fig. 8, the speed curve may be given any desired form so that a number of work pieces may be operated upon. The driving shaft 25 carries a spur wheel 3 engaging a wheel 4 integral with the inner wheel of a planetary gear carrier, the outer wheel 5 of which drives the table through the gearing shown, the reversal being controlled by a clutch K. The planet wheels 7, 8 rotate on pins carried in a loose disc 11 driven through worm gearing 12, 13 from a friction disc 14 driven by a sliding wheel 16 on the driving shaft. The latter wheel is moved radially over the friction disc 14 by suit- .able dogs 20 on the table to vary the speed of the disc 11. The arrangement is such that when the member 16 is in the position III the outer member 5 of the planetary gearing is at rest. In the position II the cutting speed v is communicated to the table, and in position I the return speed v<1> is obtained. Thus by suitably choosing the form and disposition of the dogs 20, the speed curve of the table may be modified at will. In a further modification, the curved portions of a speed curve similar to that shown in Fig. 3 are obtained by means of elliptical wheels.