US3466954A - Feeler lever for a hydraulic copying control - Google Patents

Description

Sefit. 16; 1969. A. SCHMID 3,466,954

FEELER LEVER FOR A HYDRAULIC COPYING CONTROL Filed April 12, 1967 5 Sheets-Sheet 1 INVENTOR 4/6 e=//- slwy av Sept. 16, 1969 A. SCHMID 3,466,954

FEELER LEVER FOR A HYDRAULIC COPYING CONTROL Filed April 12, 1967 5 Sheets-Sheet 2 22\ I H! i INVENTOR IAer/ Qr/nv a Sept. 16, 1969 A. SCHMID 3,

FEELER LEVER FOR A HYDRAULIC COPYING CONTROL Filed April 12, 1967 5 Sheets-Sheet 5 Fig. 5

United States Patent 3,466,954 FEELER LEVER FOR A HYDRAULIC CQPYING CONTROL Albert Schmid, Schaifhausen, Switzerland, assignor to Georg Fischer Aktiengesellschaft, Schaffhausen, Switzerland Filed Apr. 12, 1967. Ser. No. 630,295 Claims priority, application Switzerland, May 31, 1966, 7,856/ 66 Int. Cl. B23b 3/28; B23q 35/04 U.S. Cl. 32-44 Claims ABSTRACT OF THE DISCLOSURE Copying machine with a motor actuated copying carriage under the control of a template feeler which is mounted on the end of a pivoted arm with the arm connected to a motor control element, in which the plane containing the pivot axis of the arm and the point of connection of the arm to the control element is perpendicular to the feed direction of copying carriage, and the feeler is spaced from the plane on the side opposite the tool end of the copying carriage, and the point of connection of the arm to the control element is closer to the pivot axis of the arm than is the feeler.

The present invention relates to a feeler lever for a hydraulic copying control for machine tools, especially copying lathes, with a working piston fixedly connected to the basic carriage which carries out the longitudinal stroke and with a copying control valve member arranged on the copying carriage for controlling the latter in conformity with at least one templet. The copying feeler is arranged at the free end of the one-arm feeler lever which also has arranged thereon a transfer member for actuating the copying control valve member. The pivot axis of the feeler lever is perpendicular to a plane defined by two intersecting straight lines which are parallel to the feeding direction of the basic carriage and to the transverse direction of the copying carriage. The longitudinal axis of the feeler lever is approximately perpendicular to the axis of displacement of the copying carriage.

With hydraulic copying devices for copying lathes, feeler levers are employed for the transfer of the contour to be felt on a copying templet or on a pattern to the movements of the copying control valve member which controls the adjustments of the tool. Generally, the pivotal movements of the feeler lever and thus also the displacing movements of the copying control are extremely small.

Heretofore known copying controls employ feeler levers the pivot axis of which is parallel to the contour to be felt. With other known copying control devices, the pivot axis of the feeler lever is perpendicular to the contour to be felt. These last mentioned designs have the advantage over the first mentioned design that contours or curves can be felt up to self-locking inclinations without the danger of jamming.

Frequently it is desired to copy contours of work pieces which with heretofore known feeler lever arrangements could not be directly felt because on one hand jamming was unavoidable in the journalling of the feeler levers and on the other hand seizing at the copying templet occurred. With such steep feeler movements a proper functioning of the hydraulic controls is no longer assured.

It is, therefore, an object of the present invention to provide a feeler lever which will overcome the above mentioned drawbacks.

It is another object of this invention to provide a feeler lever which will permit the feeling of sieep curves without the danger that the lateral loads harmfully affect the feeler lever, and without the danger that the friction between the feeler tip and the templet exceeds permissible limits.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 diagrammatically illustrates a front view of a copying lathe.

FIG. 2 represents a side view of FIG. 1.

FIG. 3 is a partial view of FIG. 2 as seen in the direction of the arrow A.

FIG. 4 is a partial view of FIG. 3 as seen in the direction of the arrow B.

FIG. 5 represents a diagrammatic illustration of the arrangement of the feeler lever with regard to the copying templet and of the turning tool with regard to the work piece.

The problem underlying the present invention has been solved according to the present invention by an arrangement according to which the tip adapted to slide on the contour of the copying templet to be felt and pertaining to the copying feeler arranged on the feeler lever is, with regard to the longitudinal axis of the feeler lever, set back in a direction away from the turning tool, while the ratio of the distance from the pivot axis of the feeler lever to the feeler tip on one hand and to the vertical distance between the feeler tip and the longitudinal axis of the feeler on the other hand amounts to approximately 4.5: 1. Furthermore, the ratio of the lever arm extending from the pivot axis of the feeler lever to the feeler tip to the lever arm extending from the pivot axis of the feeler lever to the transfer member of the copying control member displaceable approximately parallel to the adjusting axis of the copying carriage is approximately 13:10.

Referring now to the drawing in detail, FIGS. 1 and 2 respectively show a front view and a side view of a copying turning machine with the feeler lever according to the present invention.

A turning machine bed 3 is mounted on a stand 1 provided with a headstock 2 and a lateral plate 5. The turning machine bed 3 is provided with a sliding track on which a basic carriage 7 is longitudinally displaceable parallel to the axis of rotation 10 of a work piece. This longitudinal displacement may be effected by any standard means not shown. The bed 3 is furthermore provided with a track 8 on which a tailstock 4 is longitudinally displaceable and is arrestable thereon by any standard means (not shown). Between the headstock 2 and the tailstock 4 theremay be clamped a work piece 9, for instance in a chuck 11 adapted to be driven. The basic carriage 7 is equipped with a track 12 for a copying carriage 13 which carries a turning pool 14. In any desired manner (not shown), a piston 15 or its piston rod 16 indicated in dotdash lines in FIG. 3 is fixedly connected to the basic carriage 7 and, accordingly, the copying carriage 13 forms a working cylinder (FIGS. 3 and 4) which is displaceable on the piston 15 in the direction of the double arrow 17 along an axis 18. Depending on the copying operation to be carried out on the copying turning machine, the axis 18 may be perpendicular to the axis of rotation 10 of the work piece or may form another angle therewith. In the particular embodiment illustrated in the drawing, the feeding angle 30 along the axis 18 with regard to the axis 10 of the work piece is approximately 60.

A copying templet 20 is in a maner known per se (but not illustrated) adjustable on a carrier 19 (not described in detail) above the stand 1 and the lateral plate 5. Instead of a copying templet 20, also a pattern may be used.

FIGS. 3 and 4 illustrate details concerning the arrangement of the feeler lever according to the invention. Fixedly arranged on the copying carriage 13 is a control valve housing 22 having a bore 24 in which a control column 23 by means not shown is longitudinally adjustable in a direction parallel to the direction of the working cylinder 13. The control column 23 is adapted to elfect corrections when adjusting the machine, for instance for adjusting the distance between the feeler and the contour of the templet on one hand and between the tool and the work piece on the other hand. Displaceably arranged in the control column 23 is a copying control valve member or spool 25 which is operatively connected to the feeler lever 21 by means of a transfer member in the form of a bar 26.

Fixedly arranged on control column 23 is an angular clamping member 27 with two bearing bolts 28, 29 forming the pivot for the feeler lever 21 which is adapted to pivot about the bearing bolts 28, 29 in order to carry out the small tilting movement necessary for the hydraulic control of the copying carriage 13.

An imaginary longitudinal axis 31 passing through the bearing bolts 28, 29 of the feeler lever 21 is approximately perpendicular to the displacement or feeding axis 18 of the copying carriage 13. Laterally on the feeler lever 21 (FIG. 4) in a feeler lever arm 32 there is held a feeler 33, for instance by means of clamping screws 34. In the illustrated embodiment of the invention, the feeler tip 35 pointing toward the side of the copying templet 20 and thereby also to the side of the tool 14 (FIGS. 1, 2 and is set back with regard to the longitudinal axis 31 of the feeler lever 21. The ratio of the distance 43 between the pivot bolts 28, 29 of the feeler lever 21 and the feeler tip 35 on one hand to the vertical distance 44 of the feeler tip 35 from the longitudinal axis 31 of the feeler lever 21 on the other hand amounts approximately to 4.5 :1 as optimum value, for instance 130:29 mm.

Arranged on the feeler lever 21 is a bar 26 forming a transfer member for the feeler lever movements to the copying control valve 25. The ratio of the lever arm 32 from the pivot axis 28, 29 of the feeler lever 21 to the feeler tip 35 on one hand to the lever arm 32 from the pivot axis 28, 29 to the transfer member 26 on the other hand amounts approximately to 13:10.

FIG. 5 diagrammatically illustrates the position of the feeler lever 21 with a feeler tip 35 and the contour of the copying templet 20 to be felt. Cutouts are illustrated of the contours of the non-machined work piece 40 and the finished contour 41 of the work piece 9 rotating about the work piece axis 10. The feeding angle 30 of the copying carriage 13 to the axis of rotation and thus-also of the copying turning tool 14 amounts to 60. The tip angle 36 of the feeler tip 35 amounts to 27.5. The copying turning tool 14 must have a tip angle of the same magnitude. In many instances it is desired at the transition area to merge the cylindrical portion of the work piece 9 with a collar 38 perpendicular thereto and thus to provide an undercut 39. This is of particular advantage in order to be able during a grinding operation which follows the turning operation to permit the grinding disc to run out when longitudinal grinding as well as when plane grinding.

As will be evident from FIG. 5, for instance on a raw work piece with the contour of the copying templet 20 at the transition to the collar 38 which originated with the preceding forging or pressing operation and comprises considerable additional material, the frequently irregular additional material is pre-machined by means of an additional tool 42. The contour with the undercut 39 on collar 38 can in a proper manner be produced by means of the copying tool 14 in conformity with the copying templet 20.

The operation of the hydraulic copying control as it is partially shown in FIG. 3 is known per se and disclosed for instance in German Patents 846,806; 848,289; Swiss 4 Patents 234,411; 258,652; 264,699 and Italian Patent 549,191.

The advantage of the hydraulic copying control with the feeler lever according to the present invention is seen primarily in that the copying of considerably steeper contour transition portions is made possible by the fact that the feeler tip is offset with regard to the feeler lever mounting. This was not possible with heretofore known copying controls. The lateral forces acting upon the feeler lever bearing remain in admissible limits, and also the friction inherent thereto and occurring between the feeler tip and the copying templet is within limits which permit a proper operation of the copying control.

It is, of course, to be understood that the present invention is, by no means, limited to the particular designs shown in the drawings but also comprises any modifications within the scope of the appended claims.

What is claimed is:

1. A copying machine having a frame with workpiece supporting means therein, a main carriage in the frame slidably guided therein for movement in the longitudinal direction of a workpiece in said workpiece supporting means, a copying carriage on the main carriage and having feed movement on the main carriage in a direction transverse to the workpiece and having tool means at the workpiece end for cutting the workpiece, a motor connected between the main carriage and the copying carriage for moving the latter in feed movement transverse to the workpiece, control means on the copying carriage for the motor, a feeler for following a template carried by said frame, an arm having said feeler supported thereon at one end and having its other end pivotally supported on said copying carriage on an axis extending perpendicular to both the direction of movement of said main carriage and the direction of feed movement of said copying carriage, a control element connected to said arm and to said control means to actuate the latter in response to movement of the arm about its pivotal support, the point of connection of said control element to said arm being substantially in the plane of the pivot axis of said arm which is perpendicular to the feed direction of said copying carriage, the tip of said feeler which engages the template accurately irrespective steepness being spaced offset from said plane a predetermined distance on the side of said plane opposite said cutting tool.

2. A copying machine according to claim 1, in which the point of connection of said control element to said arm is particularly closer to the pivot axis of said arm than is point of connection of said feeler.

3. A copying machine according to claim 2, in which the distance from said feeler to the pivot axis of said arm is about 4.5 times said predetermined distance of said feeler tip offset, the point of connection of said arm to said control element being closer to the pivot axis of said arm than is said feeler, and the distance from the pivot axis of said arm to said feeler being about 1.3 times the distance from said pivot axis of said arm to the point of connection of said arm to said control element.

4. A copying machine according to claim 1, in which said feeler arm extends from its pivot axis longitudinally with set back tip in the advancing direction of movement of said main carriage.

5. A copying machine according to claim 1, in which the distance from said feeler to the pivot axis of said arm is about 4.5 times said predetermined distance of said feeler tip offset.

References Cited UNITED STATES PATENTS GERALD A. DOST, Primary Examiner U.S. Cl. X.R. -62

Images