US2913807A - Drilling and tapping attachment on automatic lathe - Google Patents

Description

A. BECHLER' v 45 11 16a 15 I8 I6 11 43 DRILLING AND TAPPING ATTACHMENT ON AUTOMATIC LATHE Nov. 24; 1959 Filed Nov. 19, 1957 Nov. 24, 1959 DRILLING AND TAPPING ATTACHMENT ON AUTOMATIC LATHE Filed NOV. 19, 1957 2 Sheets-Sheet 2 United States PatentO DRILLING AND TAPPING ATTACHlVIENT ON AUTOMATIC LATHE Andr Bechler, Moutier, Switzerland Application November 19, 1957, Serial No. 697,379

Claims priority, application Switzerland June 25, 1957 2 Claims. (Cl. 2941) My present invention relates to a drilling and tapping attachment on an automatic lathe, in which a gang of working spindles are mounted on a swing rest in a rotary and longitudinally movable relation and are rotatable by means of a jack shaft which is coaxial with the swivel axis of said rest.

In such attachments, space is very limited so that in known constructions, in which on the jack-shaft rear portion are mounted two pulleys rotating in opposite sense and a clutching device for clutching the jack shaft to one or the other of said pulleys, the space in the rear of said spindles is blocked. The means for longitudinally moving the working spindle which is in the operative position, thus have to engage same laterally and, therefore, exert an eccentric force. In view of the play which never can be entirely avoided, there readily arise changes in position and vibrations which render it impossible to satisfy the steadily growing requirements as to accuracy and quiet run.

My invention aims to overcome said disadvantages of known constructions by mounting a drive shaft, which is superposed to said jack shaft and parallel thereto, rotatably about a stationary axis, on a bearing bracket affixed to the lathe bed and carrying the swing rest, said axis being situated beyond said jack shaft with respect to the work spindle which is in operative position, and further by providing, on a portion of said bracket situated above the drive shaft, a guide track for a ram disposed in the continuation of said spindle, said ram acting directly on to the latters rear end which projects from the swing rest, for the purpose of moving said spindle. I attain this and related objects by the arrangement shown, in one form and by way of example, in the drawing, in which:

Fig. 1 is a longitudinal section,

Fig. 2 shows a cross-section on the line II--II of Fig. 1, and

Fig. 3 is a side view.

A bearing bracket 2 is affixed to the rear portion 1 of the bed of an automatic lathe. In a crosswall 2a of said bracket is fixedly seated a bushing 5 by means of an intermediate ring 3 and a threaded pin 4. Another bushing 8 is seated by means of a threaded pin 7 in a plate 6 secured to thefront face of bracket 2. On these two bushings 5, 8 of which the common axis is parallel to the main axis of the lathe, a swing rest 9 and a jack shaft 10 are mounted rotatable but otherwise immovable. In three pairs of bores of rest 9, which are equidistant from the axis of the bushings 5 and 8, i.e. from the pivotal axis of said rest, bushings 12 and 13 are located by means of threaded pins 11. In each bushing pair is mounted a working spindle 14 in rotatable and longitudinally movable relation but is prevented by a slide key 15 from rotation in a sleeve 16 which surrounds the spindle and is axially locked between the respective bearing bushings. Sleeve 16 has a rim gear 16a which in any position of swing of rest 9 meshes with a spur gear 17 fixed to jack shaft 10. Between spindle 14 and sleeve 16 is inserted a compression spring 18 which is supported on a ring r 2,913,807 Patented Nov. 24, 1959 tension of pin 11 engaged in the spindle keyway. Such gearless working spindle would be provided with a common drill, while the rotating working spindles mostly carry a tap such as 20.

A rear crosswall 2b of bracket 2 is provided with a bore of which the axis is situated in the vertical plane of the bushings 5, 8 but below the latter and in which is seated a bearing bushing 21. To the rear face of a rearward tunnel-like extension 20 of rest 2 is secured by screws 22 a plate 23 in which is fixed a bearing bushing 24 coaxially to bushing 21. In the bushings 21, 24 is rotatable an axially immovable drive shaft 25 to the forward end of which is fixed a spur gear 26 which meshes with a spur gear 27 fixed to the rear end of jack shaft 10. On shaft 25, further, are mounted loosely rotatable two pulleys 25a, 25b which are driven in opposite senses by means of an electric motor, a gearing unit and two belts 28, 29. Between the latter is fastly mounted a clutch plate 30 on shaft 25, which coacts mechanically or electromagnetically with either pulley.

Actuation of swing rest 9 for the purpose of aligning I one or the other of the working spindles 14 with the lathe main axis is effected, in a manner known, by acam 31, which is fixedly mounted on a control cam shaft 32 of the lathe, through a bell crank 33 pivoted on an arm 2d of bracket 2, and through a link 34 pivoted on a threaded pin 35 to rest 9. A spring 36 tends to draw the follower 37 carried by bell crank 33 into abutment against cam 31.

The tunnel-like portion 2c of bracket 2 is provided on top with a guide track 38 for a ram 39 aligned with the lathe main axis, i.e. with the working spindle 14 which at the time is in operative position. In a recess 39a is engaged the enlarged end of a two-arm lever 40 of which the other end abuts against the control face of a bell cam 41 fixedly mounted on' shaft 32. Lever 40 is pivoted on a vertical stud 42 to an arm 2e of bracket 2. Between lever 40 and a set collar 47 fixed to the upper end of stud 42 is coiled a compression spring 43 against the action of which lever 40 is raisable. When lever 40 is in the raised position, ram 39 may be readily moved rearwardly out of track 38 so as to very materially facilitate the interchange of the spindles 14. For such interchange, a cover 45 of swing rest 9 is removed by loosening screws 44, and the working spindle which occupies the operating position is withdrawn rearwardly after loosening the screw of an appurtenant set collar 46, whereupon another spindle 14 is inserted from the rear.

When the drilling and tapping attachment is in operation, the arrangement described of ram 39 affords the advantage that the force required for feeding the working spindle 14 is acting on to the latter along the axis of rotation thereof and has no radial component.

The particular arrangement of ram 39 has been rendered possible by arranging the drive elements 26, 27 and 30 on a drive shaft 25 of which the axis is situated, with respect to the working spindle in the operative position, beyond, i.e. below, jack shaft 10. Aside of the advantages mentioned, I attain further a very compact construction of the entire attachment.

What I claim is:

1. In an automatic lathea drilling and tapping attachment having a rotatably mounted tool-holding, multiplespindle carrier having a plurality of rotatable working spindles, and angularly rotatable for selectively positioning the working spindles separately and individually in a common work position corresponding to a work station for effecting work on a workpiece, said carrier having an axis of rotation, a jack shaft coaxial with said axis and operably connected to at least one of said working spindles, the improvement which comprises, a bearing block pivotally mounting the carrier, a plunger disposed coaxially with said spindles when they are in said work position and movable axially into out of engagement with said spindles for moving the spindles in a direction corresponding to a direction for effecting work on said workpiece, a guide track slidably mounting said plunger in said coaxial position, said block having a portion supporting said guide track, a drive shaft, operably connected to the jack shaft disposed in fixed position and rotatably mounted on said block below said plunger at a distance therefrom, the pivotal axis of the carrier being disposed in a horizontal plane intermediate the plunger and the drive shaft.

2. In an automatic lathe a drilling and tapping attachment according to claim 1, including a post on said block, a two-arm lever pivotally mounted on said post for angular, upward and downward movement thereon, said plunger having a recess for releasably receiving one of said arms, a spring constantly biasing said lever downwardly into a position engaging the recess, a driven bell cam cooperative with the other arm of said lever for angularly displacing the lever to displace said plunger 10 longitudinally.

References Cited in the file of this patent UNITED STATES PATENTS Bechler July 29, 1952 2,618,841 Bechler Nov. 25, 1952

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