US1960565A - Feed variator for shapers - Google Patents

Description

May 29, 1934. w. F. ZIMMERMANN FEED VARIATOR FDR SHAPERS 2 Sheets-Sheet 1 Filed April 21' 1931 gnoemtoz y 1934. w, F. ZIMMERMAN'N 1,960,565

FEED VARIATOR FOR SHAPERS Filed April 21, 1931 2 Sheets-Sheet 2 avwewtoz 351 flame/1 A 774M441, 60 4mm Patented May 29, 1934 UNITED STATES PATENT OFFICE FEED VARIATOR FOR SHAPERS Application April 21, 1931, Serial No. 531,727

'7 Claims. ((31. 90-38) This invention deals with machine tools, and it relates more particularly to step-feed mechanisms such as are used intermittently to shift the work-table of a shaping machine, thereby to cause the reciprocating tool successively to take parallel cuts upon adjacent portions of a work-piece.

To meet the demands of the user of a machine tool of this type, it is desirable that the 10 feeding mechanism be so coordinated with the stroke of thetoolcarrying ram that thefeed will not be effected during the forward or cutting stroke thereof; that the feed mechanism be readily capable of adjustment, though be not affected by adjustments in 'the strokeof the ram; and that the mechanism be devoid of harsh mechanical actions so that it will operate quietly, efiiciently and with. a minimum: amount of wear on the parts.

From the standpoint'of the manufacturer, it is essential that the feeding mechanism be so designed :that the parts thereof may be built and assembled at a minimum of expense.

The primary object of this invention is to render available an improved step-feed mechanism for shaping machines which will meet all of the above mentioned desiderata.

This object has been attained by the provision of a feeding mechanism including a feed-nut-supported by the work-table and a feed-screw threaded through said nut and journaled in the-crossrail on which the table isslidingly mounted. An important feature of the inventionresides in the improved means'provided for giving to thefeedscrew step-by-step partial rotations during the return movements of the ram. As in conventional shaping machines, the tool-carrying-ram is given its relatively slow forward or cutting stroke and itsrelatively f-astreturn stroke by a suitable swinging lever journaled in the machine frame. This lever is actuated by a crank-pin adjustably carried by a continuously rotating bullwheel also located within the main frame of the machine. Rotation of the bull-wheel is utilized to actuate the improved mechanism which gives to the feed-screw itsstep-by-step rotary movements. A feed actuating cam, fixed to the hub of the bull-wheel, engages one arm of a two armed lever the other arm of which is connected to actuate, through a suitable ratchet-and-pawl mechanism, a forwardly extending shaft geared to the feed screw. Thus through rotation of the bull-wheel the table is given its feeding movements. The direction of table movement is controlledby a suitable clutch mechanism later to be described. The feed-actuating cam acts, upon each rotation, to shift thetwoarmed lever to predetermined extreme position. The amount of successive table feed movements is determined by the mean position to which said lever is permitted to move as the high point of the cam recedesfrom the lever. The'means for variably limiting the retractive movement of the lever, so that the operator readily may vary the feed, constitutes an important feature of this invention and will hereinafter be described in detail. 7

A feeding mechanism of this general nature is disclosed in my United States Patent No. 1,830,309 dated Nov. 3, 1931 of which the present invention is an improvement.

Other objects and advantages will be in part indicated in the following description and in part rendered apparent therefrom in connection with the annexed drawings.

To enable others skilled in the art so fully to apprehend the underlying features hereof that they may embody the same in the various ways contemplated by this invention, drawings depicting a preferred typical construction have been annexed as a part of this disclosure and, in such drawings, like characters of reference denote corresponding parts throughout all the views, of which:-

Figure 1 is a side elevation of a shaping machine embodying the present invention. Fig. 2 is a vertical section substantially on the line 2-2 of Fig. 1. Fig. 3 is a vertical section substantially on the line 33' of Fig. 4 and Fig. 4 is a horizontal sectionshowi-ng certain of the interiorelements of the assembled feedmechanism.

Referring more specifically to the drawings, the invention is disclosed as embodied in a shaping machine comprising a main frame formedof a base A and an upstanding closed housing B supported thereon. Reciprocably mounted on-guideways provided by the upper portion: of the main frame is a tool carrying ram C which carries, at its forward end, the usual cutting tool in a manner common to machine tools of this type. The work to be machined is usually supported upon a suitable table T translatably mounted on .a cross rail R adjustably secured upon the forward face of the main frame. Journaled lengthwise of the cross rail is a feed screw S which has a threaded engagement with a feed nutN non-rotatably carried by the work-table. Means later to be described is provided for giving to the feed screw intermittent rotary movev against the cone 21 by a spring 23. the bevel gear 22 to rotate as a unit with the ments thereby to effect step-by-step feed of the work-table.

Reciprocatory motion is given to the ram by means of conventional mechanism including a slotted lever L actuated by a crank-pin P carried by a bull-wheel D, which, in turn, derives motion from a shaft E through suitable change gears F. These elements being conventional, detailed illustration and description thereof is deemed unnecessary.

Fixed to the bull-wheel D and rotatably journaled in the main frame of the machine is a sleeve-like hub 1, the rotation of which is utilized to actuate the improved intermittent table feed.

To the hub 1 is secured, as by means of a flange 2, a feed actuating cam 3 the periphery of which is adapted to engage an arm a of a two-armed lever 4, fulcrumed on a rod 5, sup' ported by a sub-casing 6, secured upon the side of the main frame. A spring 7, having one end connected to the lever 4 and the other end connected to the main frame, tends to swing the lever counter-clockwise, as viewed in Fig. 3 to cause the arm a (or a roller a carried thereby) continuously to bear against the periphery of the cam. Thus it will be understood that in each rotation of the cam the high point thereof will swing the lever 4 clockwise to an extreme posi tion as shown in Fig. 3. Upon retraction of the high point of the cam, due to rotation thereof, the arm a of the lever 4 will (through the action of the spring) follow the receding periphery of the cam. From the foregoing it will be understood that unless some means is provided to limit the retractive movement of the lever it would be given the complete throw of the actuating cam.

Oscillatory motion of the lever 4 is utilized 'to effect, in the feed screw, step-by-step rotary motion and means is provided for limiting the movement of said lever thereby to vary the feed rate, as will now be described.

The arm b of the lever 4 is provided with a gear segment 8 in mesh with a gear 9 rotatably mounted, by means of a bushing 10, on a stub shaft 11 journaled in the sub-casing 6. Also journaled on the bushing 10 and keyed to the hub of the gear 9 is an oscillator 12 which carries a spring-pressed pawl 13 adapted to engage the teeth of a ratchet wheel 14 keyed to the shaft 11. Thus oscillation of the lever 4 effects, through the gear 9, oscillator 12 and pawl 10, step-by-step rotation of the ratchet wheel 14 and the shaft 11 upon which it is secured. To prevent the pawl 10 from pulling the ratchet wheel backwards by friction a pair of spring pressed stop pawls l5 and 16 are maintained in engagement with the ratchet and prevent retrograde rotation thereof.

Secured upon the forward end of the shaft 11 is a bevel gear 17 which meshes with and drives a similar gear 18 fixed upon one end of a sleeve 19 telescopically connected to the splined 05 end portion 20 of a shaft 20. This shaft has, at its forward end, a cone head 21. A bevel gear 22 loosely encircling the shaft 20 has a counter-cone socket which is spring-pressed This causes shaft 20 except in the event of abnormal strains during which slippage may take place to prevent breaking of the parts. The bevel gear 22 is simultaneously in mesh with reversing bevel gears "24 and 25, which, by means of the usual clutch sleeve 26, may be used to drive the feed screw S which intermittently feeds the table T. To protect the running shafts, a casing 27 is pivoted coaxially about the unthreaded end of the feed screw shaft and telescopes with a casing 28 which likewise pivots coaxial with the shaft 11, this arrangement accommodating the rise and fall of the cross rail at the front of the machine.

From the foregoing it will be seen that stepby-step rotation will be transmitted to the feed screw by rotations of the feed actuating cam 3.

As hereinbefore stated this invention provides novel means for varying the rate at which the table is fed under the actuation of the constant throw feed cam. This is effected by limiting, to any desired extent, the retractive movement of the lever 4 after it has been fully advanced by said cam. The improved means for accomplishing that purpose comprises an abutment wall 30 provided by a member 30, in the nature of a sector, pivotally mounted upon the shaft 5 adjacent the oscillating lever 4. The stop-wall 30 is adapted, during retractive movement of the lever 4, under the influence of the spring '7, to be engaged by a portion of said lever, or by a stud a carried thereby, to prevent the lever from partaking of the full throw of the feed cam. To regulate the feed to any desired rate, manual means is provided for adjusting the member 30 about the rod 5 thereby so to position the stopwall 30 as to arrest the lever 4 in its retraction at any desired position in its normal stroke. This means includes a gear 31 in mesh with the teeth of a gear segment 30 provided by the member 30. A dial 32, fitted with an actuating lever 33, is fixed to the hub 31 of the gear 31, exteriorly of the sub-casing 6 and serves as means to rotate the gear 31 thereby to vary the position of the abutment 30 The feed effected by any given adjustment of the dial may be determined by a scale of graduations 32 carried by the dial. A spring detent 84 carried by the sub-casing 6 maintains the dial and the parts connected therewith in adjusted positions.

Without further analysis, the foregoing will so fully reveal the gist of this invention that others can, by applying current knowledge, readily adapt it for various utilizations by retaining one or more of the features that, from the standpoint of the prior art, fairly constitute essential characteristics of either the generic or specific aspects of this invention and, therefore, such adaptations should be, and are intended to be, comprehended within the meaning and range of equivalency of the following claims:

Having thus revealed this invention, I claim as new and desire to secure the following combinations and elements, or equivalents thereof, by Letters Patent of United States:

1. In a shaping machine having a ram, an adjustable stroke reciprocator therefor, a table, and a table-feeding transmission; a one-way motion transmitter for actuating said transmission comprising an actuator synchronized with said reciprocator; a two-armed lever fulcrumed on an axis parallel to the axis of said reciprocator and adapted tobe oscillated thereby, one arm of said lever being adapted to be advanced by said actuator to a predetermined extreme position; a gear segment formed on the other arm of said lever; a, gear in engagement with and oscillated by said segment; a ratchet and pawl mechanism actuaated by said gear and operatively connected to operate said table feeding transmission; yielding means tending to hold said lever in'engagement with said actuator; and an adjustable abutment for limiting the retractive movement of said lever under the influence of said yielding means.

2. In a step-feed mechanism for machine tool tables having a rotatable screw and a non-rotatable nut carried by the table and having a threaded connection with said screw; means for intermittently giving rotary movements to said screw, said means comprising a shaft geared to said screw; a positive throw rotary element; a two-armed lever having one end maintained in the path of said rotary element and adapted to be advanced thereby to an extreme position; means to retract said lever after its advance by said rotary element; means comprising an adjustably mounted abutment for limiting the retractive movement of said lever; a gear segment carried by the other arm of said lever; a gear meshing with said segment and adapted to be oscillated thereby; and means actuated by said gear to give step-by-step rotary movements to said shaft.

3. In a shaping machine having a ram and means including a rotary bull-wheel and a lever actuated thereby for reciprocating said ram, a table, and a table-feeding mechanism; a oneway motion transmitter for actuating said table feeding mechanism comprising a cam rotatable with said bull-wheel; a two-armed lever fulcrumed intermediate its ends, one arm of said lever being adapted to be advanced by said cam to a predetermined extreme position; a gear segment formed on the other arm of said lever; a gear in engagement with said segment; a ratchet and pawl mechanism actuated by said gear and operatively connected with said table feeding mechanism; yielding means tending to hold said lever in engagement with said cam; an adjustable member affording an abutment for limiting the retractive movement of said lever under the influence of said yielding means; a gear segment formed on said member; a gear in mesh therewith; and manual means for rotating said gear to vary the position of said abutment.

4. In a step-feed mechanism for machine tool tables having a rotatable screw and a non-rotatable nut carried by the table and having a threaded connection with said screw; means for intermittently giving rotary movements to said screw, said means comprising a shaft geared to said screw; a rotating cam; a two-armed lever having one end maintained in the path of said cam and adapted to be advanced thereby to an extreme position; spring means to retract said lever after its advance by said cam; means comprising an adjustable element providing an abutment wall for limiting the retractive movement of said lever; a manually adjustable member; a gear connection between said member and said adjustable element for shifting said abutment wall by movement of said member; a gear segment carried by the other arm of said lever; a gear meshing with said segment and adapted to be oscillated thereby; and means actuated by said gear to give step-by-step rotary movements to said shaft.

5. In a table feed mechanism having a rotary screw and a cooperating nut carried by the table; a constant throw rotating feed actuating cam; means for giving to said feed screw step-by-step rotary motions of varying amplitude from said constant throw cam, said means including an oscillatory lever fulcrumed intermediate its ends and having one arm engaging the periphery of said cam and adapted to be shifted to a predetermined extreme position thereby; yielding means tending to hold said arm in engagement with said cam as the periphery thereof recedes from said arm; a segment formed on the other arm of said lever; a gear engaging said segment and adapted to be oscillated thereby; means for transmitting to said feed screw step-by-step rotary movements from the oscillatory movements of said gear; means for limiting the movement of said lever under the influence of said yielding means comprising a member pivoted adjacent the fulcrum of said lever and affording a stop wall adapted to engage said lever and obstruct the retracting movement thereof; a manually adjustable element; and a gear connection between said manually adjustable element and said member for shifting the latter about its pivot to vary the position of said stop: wall.

6. In a shaping machine having a ram and means including a rotary bull-wheel and a lever actuated thereby for reciprocating said ram, a table, and a table feeding mechanism; a oneway motion transmitter for actuating said table feeding mechanism comprising an actuator rotatable with said bull-wheel; a two-armed lever fulcrumed intermediate its ends, one arm of said lever being adapted to be advanced by said actuator to a predetermined extreme position; a gear segment formed on the other arm of said lever; a gear in engagement with said segment; a ratchet and pawl mechanism actuated by said gear and operatively connected with said table feeding mechanism; yielding means tending to hold said lever in engagement with said actuator; an adjustable member affording an abutment for limiting the retractive movement of said lever under the influence of said yielding means; a gear seg ment formed on said member; an adjusting gear mounted coaxial with the axis of said actuator and meshing with the gear segment on said adjustable member; and manual means also coaxial with said actuator for rotating said adjusting gear and thereby said adjustable member to vary the position of said abutment.

7. In a shaping machine having a ram and means including a rotary bull-wheel and a lever actuated thereby for reciprocating said ram, a table, and a table-feeding mechanism; a one-way motion transmitter for actuating said table-feed.- ing mechanism comprising a cam rotatable with said bull-wheel; a two-armed lever fulcrumed intermediate its ends, one arm of said lever being adapted to be advanced by said cam to a predetermined extreme position; a gear segment formed on the other arm of said lever; a gear in engagement with said segment; a ratchet and pawl mechanism actuated by said gear and operatively connected with said table feeding mechanism; yielding means tending to hold said lever in engagement with said cam; an adjustable member pivoted coaxial with the fulcrum of said lever and affording an abutment for limiting the retractive movement of said lever under the influence of said yielding means; a gear segment formed on said member; an adjusting gear mounted coaxial with the axis of said rotatable cam and meshing with the segment on said adjustable member; and a manually rotatable member arranged coaxial with said adjusting gear and operatively connected therewith to shift said gear and its engaged segment thereby to vary the position of said abutment.

WILLIAM F. ZIMMERMANN.

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