Патент USA US2387582код для вставки
BROACHING APPARATUS Filed Maich las;` v1945 YDRILL ` I8 Y Flsfs ' , "IN1/Enron; w. HA ~ Patented Oct. 23, 1945 ' UNITED 2,387,582 STATES PATENT OFFICE BROACHING APPARATUS >Fred W. Helmîng, Waterbury, Conn.„assignor to The Bristol Company, Waterbury, Conn., a cor poration of Connecticut application March 18, 1943,.serial No. 479,545 44 Claims. (c1. 90-33) This invention relates to broaching operations, ing the broaching operation. Since this involves and is more particularly concerned with a novel apparatus adapted for use in connection with a screw machine wherein a breaching action forms one of a number of successive operations, of no actuation of clutches or other starting and stopping devices, the mechanism may be very materially simplified, the wear and tear of opera tion greatly reduced, and the breaching time re which the majority require rotary motion of the work with respect to the processing tool. In the duced to a minimum. In the drawing: manufacture of set screws and the like on a pro- I ~ I Fig. 1 is a top elevation of a portion of an automatic screw machine including a device em duction basis, it is customary for the material upon which operations are being performed to be bodying the principles oi the invention. carried in a rotating spindle and rto have pre- v Fig. 2 is a side elevation partly in sectionV of a sented theretothe tools necessary to the several broach mounting embodying the principles of in forming operations in the production of a fin ished unit. It is obvious that if the successive Feb. 3 is a front elevation of the same. operations can be carried out without bringing to 154 Figs. 4 and 5 are a side and front elevation vention. I , rest the rotating spindle which carries the mate respectively of a spindle adapted to the purposes rial, there will be effected a saving in time and of the invention. also a decided reduction in wear and tear on the In some methods of production of screws hav ing a recessed or splined head, it is necessary ‘ In Fig. 1 is shown a top `view of a screw ma chine or turret lathe adapted to the purposes of the invention. Mounted upon a lathe bed I0, is` a headstock II havingtherein a rotatable spin that certain operations be performed by a broach or similar tool whose motion relative to the workpiece is purely axial or longitudinal. Since it is frequently expedient that said axial com ponent of the forming process be performed be die I2 adapted to be rotated about its axis by means of a pulley I3. Carried by the spindle I2 is a chuck I_4 adapted to grip a workpiece I5 which is to be subjected to certain formi?gproc esses. Slidably mounted upon the lathebed I0, machinery. »tween two operations involving rotary motion, it becomes necessary that the workpiece be tem porarily brought to a state where it will have no rotary motion with respect to the broach. In the conventional method for performing such op erations, it has been customary to make use of a broach rigidly fixed to the tailstock or turret head of the machine, and to present this tool to the workpiece only after the latter has been brought to rest by stopping the motion of the spindle in the headstock. , It is an object of the present invention te pro vide a means for `carrying out the breaching ac and adapted for motion therealong in a sense O . parallel to the axis of the spindle I2, is an. apron I6 carrying a turret head Il, which may be r0 tated with respect to said apron about an axis perpendicular `to that of the’ spindle I2. Mounted upon the turret head I 'I is a plu rality of tools or forming elements adapted to perform in a predetermined succession a series In the , of operations upon the workpiece I5. drawing are indicated three such tools, viz., a drill I8, a broach I 9, and a threading die 20. The turret head I1 may, of course, carry other tools, but the three which have been mentioned tion as one of a series of successive operations 4.o are suiiîcient to illustrate the purposes and prin without the need for bringing the spindle to rest or in any way altering its velocity. ciple of the invention. The mechanism for ro tating the turret head Il with respect to the In the present invention it is proposed to pro apron I6, and for advancing said apron together vide a rotatable mounting for the breaching tool, with the turret head carried thereby, in order 45 and further to provide means whereby said to present to the workpiece I5 such forming ele mounting will automatically be caused to rotate ments as may be borne by the turret head, con coaxially with, and at the same speed as, the stitutes no part of the present invention, and, spindle at the time of being presented to the being well known to those familiar with this class workpiece to carry out the breaching operation. of machinery, herein requires no further de Thus, instead of it being necessary to provide 50 scription means for bringing the spindle to rest during the As an example of a process in which each of broaching operation, it is only required to leave these tools forms a part, consideration may be the breaching tool mounting free to rotate as given to certain elements in the machining of a much as may be necessary to maintain the broach recessed head set screw from a length of bar stock. 55 at the same angular velocity as the spindle dur The stock is represented by the workpiece I5, Pr . _ 2,387,582 which is ñrmly gripped in the rotating chuck I4 for the purpose of having the several de sired operations performed thereon. The fol chuck and a bevelled surface 38, and lso disposed that as the breaching element is juxtaposed thereto the extremity of one or other of the lowing operations represent normal practice in springs `32, 33, will be engaged by the surface 31, causing the collet 28 to assume the rotation of the chuck I4 and the broach thus to be rotated The turret head I1 being first so positioned that at the same velocity as the workpiece I5. As .the the drill I8 lies on the axis of the machine, the broach is farther advanced it will engage the apron I6 is advanced toward the headstock I1, workpieceV I5 and will enter the previously drilled presenting the drill I8 to the workpiece I5 and causing a hole of the proper depth to be centrally 10 hole in the end thereof, and will carry out its breaching operation in the same manner as drilled in the projecting end thereof. The apron though both the workpiece and the broach were I6 is then withdrawn, and the turret head I1 devoid of angular rotation. As the broach is rotated to such a position that the broach I9 forced >to the bottom of the recess, the springs lies on the axis of the machine. In the art as heretofore practiced, it would now be necessary 15 32, 33 will yield sufficiently to permit free axial motion of the broaching tool; and as said tool is to bring the chuck I4 to rest, after which the withdrawn, said springs will assist in clearing the apron I5 carrying the turret head I1 would be broach from the workpiece. advanced, and the broach I9 forced into the hole , While the springs 32 and 33 provide means for which had been drilled in the extremity of the workpiece I5. This broach being shaped to a 20 bringing the rotating collet 28 up to the same 'speed as the chuck I4 before any stress is ap suitable contour (as for example that Shown in plied to the broach I9, it has been found in the the set screw fully described and set forth in U. S. smaller sizes of the device, where the inertia of Letters Patent 1,075,710, issued to D. S. Goodwin, the movable parts is relatively low, that these October 14, 1913), the interior of the recess will thus be given a nuted or splined conformation, 25 springs may be omitted, and that upon its first adapted for engagement by a similarly conformed engagement with the recess in the workpiece I5 the broach I9, together with the collet 28 and wrench. The apron I6 Yis again retracted, and associated parts, will assume the angular Velocity the broach I9 withdrawn from the recess in the of the chuck I4 without damage or objectionable screw, after which iït is necessary that the spin die I2 carrying the workpiece I5 again be 30 strain. Upon withdrawal of the broach I9 from the workpiece I5, the turret head I1 will be ad brought into rotation. The turret head I1 is vanced to a new position, and the threading oper rotated toA such a position that the die 20 is ation carried out by the die 20 as hereinbefore caused to lie on the axis of the machine, after described. „ which the turret head is again advanced and the die presented to the projecting portion of the .35 The terms and expression whichl I have em ployed are used as terms of' description, and not rotating'workpiece I5 to form thereon a suitable of limitation, and I have no intention, in the screw thread. use of such »terms and expressions, of excluding As hereinbefore noted, my invention enables any equivalents of the features shown and de the broaching action to be accomplished with out bringing the spindle I2 to rest or in any way 40 scribed or portions thereof, but recognize that various modifications are possible within the altering its velocity. This may be effected by scope of the invention claimed. means ysuch as illustrated in Figs. 2-5 of the the forming of a set screw having a recessed head: drawing. I claim: . - 1. Broaching apparatus comprising holding More particularly, -in Fig. 2 is shown a side elevation, partly in section, of a mounting which 45 means for a workpiece, means for rotating said holding means, a breaching tool holding means permits free rotation of the broach I9. A base adapted to be rotated about the axis of said portion 22, having a projecting cylindrical shank workpiece and simultaneously advanced along 23 adapted to be ñxed within the turret head I1 said axis with respect to said workpiece, and of the screw machine, is provided with a recess 2li and a clamping plate 25 adapted to be secured 50 means cooperating with the first mentioned hold ing means for transmitting to said broaching tool 'to :the base portion 22 by means of suitable bolts rotary movement about only the axis of said 23, and to form therewith a housing for a ball workpiece, said transmitting means comprising a A bearing men1ber21 of a type especially adapted to helically conformed spring extending from one resist thrust or axial.stresses. Carried within the ball-bearing 21, and free to rotate with the 55 of said holding means and Aadapted to engage one of its ends with a portion of the other of said inner portion thereof is a collet 28 secured to said holding means prior to engagement of said bearing by means of a nut 29 freely rotatable broach with said workpiece and thereby to act as with said collet in the recess 24. Centrally fitted a driving member for said broach in a circum- , within the collet 23 and secured therein by a set screw or other suitable clamping means, not ’ 60 ferential sense while remaining resilient in an axial sense. shown in the drawing, is a bushing 38 adapted to 2. Broaching apparatus comprising holding support the broach I9 by engagement with a means for a workpiece, means for rotating said suitably threaded screw 3| abutting upon the holding means, a broaching tool holding means rearward end of said broach. » Secured to the front end of the collet 28 is a 65 adapted to be rotated about the axis of said work piece and simultaneously advanced along said pair of- helically formed semi-circular springs axis with respect to said workpiece, and means 32 and 33, normally projecting a slight distance cooperating with the ñrst mentioned holding axially from the surface 0f said collet, but adapt means for transmitting to said broaching tool ro ed to be compressed into substantial engage ment therewith under the action of a longitudi 70 tary movement about only the axis of said work piece, said transmitting means comprising a leaf nal force. spring extending from one of said holding means Secured to the chuck I4 is a ring 35, shown in and adapted to engage a portion of the other of Figs. 4 and 5, and having in the surface thereof said holding means prior to» engagement of said a notch 38 formed by the intersection of a plane surface 31 parallel to the axis of rotation of the 75 broach with said workpiece and thereby to relieve 3 2,387,582 said broach of undesirable torsional stresses in init'iating said rotation thereof. 3. Broaching apparatus comprising holding means for a workpiece, means for rotating said holding means, a breaching tool holding means adapted to be> rotated about the axis of said Work piece and simultaneously advanced along said axis with respect to said work piece, and means cooperating with the ñrst mentioned holding while remaining axially resilient and relieving said tool of undesirable stresses in initiating said y rotation thereof. _ 4. Broaching apparatus comprising holding means for a workpiece, means for rotating said holding means, a broaching tool holding means movable axially of said workpiece and also free for rotation with said workpiece for forming rec tilinear surfaces on said workpiece, and means means for transmitting to said broaching tool ro 10 interposed between the last mentioned holding tary motion about only the axis of said work means and the means for rotating said workpiece piece, said transmitting means comprising a for transmitting rotary movement from said ro spring extending from one of said holding means tating means to said breaching tool, said trans towards the other and of such length as to en mitting means comprising a spring of such length gage a portion of the other of said holding means 15 as to transmit rotation to said broaching tool prior to engagement of said broaching tool with said workpiece for driving said broaching tool while remaining axially resilient. FRED W. HELMING.