US3842633A

US3842633A - Resiliently biased starter blade supporting arm for thread roller

Info

Publication number: US3842633A
Application number: US00424664A
Authority: US
Inventors: R Morton; E Grohoski
Original assignee: Hartford Special Machinery Co
Current assignee: National Machinery Co
Priority date: 1973-12-14
Filing date: 1973-12-14
Publication date: 1974-10-22
Anticipated expiration: 1991-10-22
Also published as: BR7408997A; JPS5412106B2; JPS5093253A; DE2453088A1; GB1426149A

Abstract

A thread roller starter mechanism has a starter blade assembly which is paced for operation by a one-way actuating drive which effects retraction of the starter blade assembly from a starting position. The assembly includes a cantilever mounted arm with a starter blade supported on a free end of the blade supporting arm which is resiliently biased to urge the starter assembly to return toward the starting position and to provide a preselected work blank starting force independent of the actuating drive.

Description

United States Patent [191 Morton et a1.

[4 act. 22, 1974 Edward G. Grohoski, Litchfield, both of Conn.

[73] Assignee: The Hartford Special Machinery Company, Simsbury, Conn.

[22] Filed:

Dec. 14, 1973 [21] Appl. No.: 424,664

52 us. Cl. 72/90 [51] Int. Cl B2111 3/06 [58] Field of Search 72/90, 88; 10/2, 10; 221/21 [56] References Cited UNITED STATES PATENTS 3,139,776 7/1964 Friedman 72/90 3,371.820 3/1968 Grohoski et a1. 72/90 X Primary Examiner-Milton S. Mehr Attorney, Agent, or Firm-Prutzman, Hayes, Kalb & Chilton [5 7] ABSTRACT A thread roller starter mechanism has a starter blade assembly which is paced for operation by a one-way actuating drive which effects retraction of the starter blade assembly from a starting position. The assembly includes a cantilever mounted arm with a starter blade supported on a free end of the blade supporting arm which is resiliently biased to urge the starter assembly to return toward the starting position and to provide a preselected work blank starting force independent of the actuating drive.

7 Claims, 2 Drawing Figures RESILIENTLY BIASED STARTER BLADE SUPPORTING ARM FOR THREAD ROLLER This invention generally relates to thread rollers and specifically concerns an improved starter mechanism for such machines of a type generally described in our US. Pat. No. 3,371,820 entitled Starter Mechanism for Thread Rolling Machine issued Mar. 5, 1968 and assigned to the assignee of this invention.

A principal object of this invention is to provide an improved starter mechanism having a starter blade assembly the weight and inertia of which is reduced to a minimum for rolling threads on exceptionally lightweight blanks at normal high speed operation.

Another object of this invention is to provide an improved starter mechanism of an overload release type wherein the starter blade return is independent of its drive which is a one-way operating drive for pacing operation of the starter blade.

A further object of this invention is to provide an improved starter mechanism wherein the stroke length of the starter blade is adjustable for blanks of different diameter size without requiring any change in the feed control contour of a drive actuating cam.

Still another object of this invention is to provide an improved starter mechanism which is suited particularly for feeding exceptionally lightweight blanks at a high machine production rate exactly the way it does when the machine is being turned over manually during slow speed adjustment to insure that the thread rolling dies of the machine are in match.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

A better understanding of the objects, advantages, features, properties and relationships of the invention will be obtained from the detailed description and accompanying drawings which set forth an illustrative embodiment and is indicative of a way in which the principle of the invention is employed.

In the drawings:

FIG. 1 is a partial plan view of a thread rolling machine showing a starter mechanism which is the subject of this invention; and

FIG. 2 is an enlarged side elevational view, partly broken away and partly in section, showing certain component parts of a starter blade assembly.

Referring to the drawings in detail, a thread rolling machine is illustrated in FIG. 1. The machine 10 includes an elongated frame on table 12 on which is mounted a feed chute or guide track 14 for conveying blanks 15 in line from a hopper, not shown, to a pair of cooperating stationary and reciprocable dies 16 and 18 respectively. The stationary die 16 is mounted on a stationary die block 20, and the reciprocable die is mounted to a slide 22 by an adjustable clamp assembly 24.

Slide 22 is supported for reciprocable movement on a slide block 26 which can be adjusted on table 12 by suitable fasteners 28 for insuring alignment of the spacing between the stationary and reciprocable dies 16 and 18. A suitable clamp assembly 30 is provided for also making fine adjustment of the stationary die 16 to permit an operator to eliminate undesired clearances. Such adjustment of the stationary die 16 is not normally provided for, but in this machine it is desirable in an effort to optimize all aspects of blank handling in view of the exceptionally small blanks which are being rolled, and if desired, suitable means including fasteners 31 may be provided to effect adjustment of stationary die 16 parallel to guide track 14.

Guide track 14 will be understood'to be downwardly inclined so that blanks are fed between rails 34 of track 14. A combination gate and starter blade 36 is mounted adjacent an open end of track 14 for reciprocable movement between stationary and reciprocable dies 16 and 18. Blade 36 is driven for successively feeding each end blank from track 14 to between the starting ends of dies 16, 18. The feeding of each blank is initiated and timed to cooperate with reciprocable movement of slide 22 by a cam 38 attached to and rotating with crank wheel 40.

To reciprocate slide 22 and therefore the driven reciprocable die 18, crank wheel 40 has one end of a pitman arm 42 eccentrically pivotally mounted on a crank wheel 40, and the other end of pitman arm 42 is pivotally connected to slide 22 by pivot pin 44. For each revolution of crank wheel 40, reciprocable die 18 is driven through one complete cycle with the stroke of die 18 being dependent upon the eccentricity of the pivotal mounting of pitman arm 42 to crank wheel 40. To pace operation of starter blade 36, a drive mechanism 46 is provided which serves to retract starter blade 36 in one linear direction to open the end of track 14 and to remain open long enough for the single end work blank to be admitted from track 14 into position between the starting end of each die 16, 18. The end blank is to be positioned against the face of the moving die 18 at least by the time the moving die 18 comes to position at the completion of its backstroke andreverses direction. Then the work blank is wedged between the starting ends of the dies 16, 18 by blade 36 to be accurately provided with a thread rolled onto the periphery of the-blank upon movement of the reciprocable die 18 relative to the fixed die 16. The feeding of each blank is timed to cooperate with the reciprocable movement of slide 22.

Drive mechanism 46 includes a bell crank 48 mounted on a pivot pin 50 secured to the table 12. Bell crank 48 has an arm 52 suitably connected by pivot pin 54 to a rod end 56 of turnbuckle 58. Its opposite ends are threadably connected to rod end 56 and to a similar rod end 60 pivotally connected by pin 62 to a cam roll lever 64 pivotally mounted at 66 on a starter engage lever 68 supported for pivotal movement on table 12 on a rotary support unit 70. Spring 72 is connected between a post 74 fixed to table 12 and point 75 on arm 76 of the starter engage lever 68 to urge cam roll 78, pivotally supported on lever 64, toward a disengaged position relative to a feed control contour formed on the outer periphery of cam 38.

Cam roll 78 may be disengaged from cam 38 under the force of spring 72 upon retraction of a positive adjustment stop 80 from its illustrated position in FIG. 1. Stop 80 is shown having an actuator rod 82 which is connected to a hand operated knob 84. Knob 84 controls the position of the stop 80 and, therefore, the position of pivot point 66 which will be understood to be fixed during normal operation to establish the pivot point for cam roll lever 64 for an operating cycle of the machine 10 with cam roll 78 engaging cam 38.

Cam roll 78 is maintained in constant contact with cam 38 during operation by a drive return spring 88 (FIG. 2) housed within drive block 90. One end of spring 88 is seated against a spring adjustment plug 92,

received in a threaded end of bore 94 of block 90. An opposite end of spring 88 surrounds a reduced end portion 95 of a drive plunger 96 against which spring 88 seats to urge plunger 96 into engagement with lug 98 of bell crank 48 which is part of the drive mechanism 46. Accordingly, bell crank 48 is urged counterclockwise as viewed in FIG. 1 by spring 88 to bias cam roll lever 64 clockwise, via turnbuckle 58, to maintain cam roll 78 in engagement with cam 38.

A high point or position of maximum radius 100 on the contour of cam 38 forces cam roll lever 64 counterclockwise about its pivot point 66 as viewed in FIG. 1 to drive bell crank 48 in one angular direction (clockwise) about its pivot pin 50 against the bias of the drive return spring 88 to retract blade 36 from its illustrated starting position and open the discharge end of feed rails 34 of track 14, for discharging an end work blank onto the starting ends of dies 16, 18. Such action is achieved by a starter blade actuating post 104 of bell crank arm 102 which is in one-way driving engagement with an L shaped mounting'plate 106 for blade 36 to cause blade 36 to be retracted in one direction from its starting position (from right to left as viewed in FIG. 1) to open the end of track 14 to permit blank discharge. Subsequent to discharging the blank, cam roll 78 passes high point 100 of cam 38 to permit drive return spring 88 to move lug 98 of bell crank 48 in a counterclockwise direction as shown in FIG. 1, thereby returning the starter blade actuating post 104 to its illustrated start position and permitting return of starter blade 36 to its illustrated starting position.

Drive mechanism 46, specifically its bell crank 48 and starter blade actuating post 104, provides asole connection and drive for starter blade 36. In accordance with this invention, a simple and lightweight starter blade assembly of improved responsiveness and minimal weight and inertia is provided wherein each end blank is subjected to an exceptionally low starting force limited to only a spring return during insertion of the blank between the rolling dies 16, 18 to insure that each blank is not driven beyond the match point of the dies, i.e., when they are matched with the thread crests opposite the thread roots to ensure accurate thread tracking without shaving the thread flanks. As will be readily recognized by those skilled in the art, exacting requirements as to the resultant work blank starting force are absolutely essential to roll threads on exceedingly small blanks, e.g., small diameter size ranges from approximately 0.045 to 0.125 diameter blanks.

To accomplish the foregoing purposes, a starter blade supporting arm 110 is shown as being preferably formed of a flat strip of spring steel cantilever mounted by a suitable fastener 112 on block 90 to extend in overlying relation to pivot pin 50 of bell crank 48 toward the work station. A free end of arm 110 is secured to leg 114 of the mounting plate 106 by machine screws 108 with leg 116 projecting perpendicular to leg 114 and serving as a support for blade 36 which is secured thereto by any suitable means. A movable adjustment stop 118 is shown extending through arm 110 and plate 106 with a protruding end portion engageable with a fixed stop l20on block 90, a lock nut 122 serving to secure stop 118 in adjusted position. The disclosed construction serves to provide a fine adjustment feature. Normally during set up, the drive mechanism 46 is disengaged to shift pivot point 66 to the right of its illustrated position in FIG. 1, and the starting position of blade 36 is established by the stop 118. The turnbuckle 58 is then adjusted to bring post 104 into contact with the plate 106 to precisely locate the extreme position of blade 36 in a blank feeding direction during operation. This feature is also particularly useful in limiting blade position to close the feed track 14 when drive mechanism 46 is disengaged.

Arm 110 not only supports blade 36, but the resiliency of the spring material itself supplies a propelling force to apply a following motion tostarter blade 36 in a blank feeding direction in response to a return movement of bell crank actuating post 104 and a work blank starting force to wedge each end blank between starting ends of dies 16, 18. The spring force which the blank is subjected to accordingly may be designed to be exceptionally low, being only enough to cause arm 110, blade 36 and its mounting plate 106 and the work blank to follow the return motion of post 104 effected by the cam 38 on cam roll lever 64. An additional advantage will be seen wherein the exceptionally light starting force supplied by arm 110 is insufficient normally to initiate movement of blade 36 upon occurrence of an abnormal condition as in the case of a jammed blank obstructing normal feeding of the machine 10, while bell crank 48 will be permitted to continue to oscillate responsive to the drive mechanism 46.

In the specifically illustrated embodiment, a flat strip of spring material is shown at 124 having one end mounted on block by fastener 112 in lapping relation to arm and positioned to coextend therewith in supporting relation along a substantial length of arm 110. Spring 124 serves to effect a desired additional spring loading to arm 110 upon its being strained when retracted by bell crank 48 while further serving to stabilize arm 110 to minimize undesired oscillation during high speed operation.

Another feature of the disclosed construction resides in the provision for timing control and stroke length adjustment of the end position of the retracting extreme limit position of starter blade 36. For this purpose, an arcuate slot 126 is formed in cam roll lever 64 along an arc equidistant from pivot pin 54 connecting bell crank arm 52 to turnbuckle 58. When cam roll 78 is on the low point of the periphery of cam 38 as illustrated in FIG. 1, the starting position of blade 36 as depicted in FIG. 1 will remain constant while the retraction of blade 36 from the starting position may be adjusted by varying the position of pivot pin 62 within its slot 126 between a maximum at one end of the slot 126, as illustrated, and a minimum at the opposite end of the slot. A maximum stroke length may be achieved, e.g., of about three-sixteenths inch travel, while a minimum stroke length is achieved, e.g., of about three thirtyseconds inch travel for finished diameter screw blanks ranging between 0.125 and 0.045 inches at machine production rates of 1,000 pieces per minute. Accordingly, the length of starter blade travel can be tailored by this adjustment to suit the spacing of the guide track 14 as required for feeding blanks of varying diameters.

In view of the disclosed construction, the only force exerted on starter blade 36 is that effected by the resil ient biasing force of the starter blade assembly itself which produces a following movement relative to the actuating post 104 of bell crank 48 in a blank feeding direction upon return movement of the drive mechanism 46. In addition, starter blade stroke length control is effected by the disclosed stroke adjustment means in the cam follower linkage of the drive mechanism without any need whatsoever of changing the throw of the drive actuating cam 38.

As will be apparent to persons skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the teachings of the present invention.

We claim:

1. A starter mechanism for high speed gating and feeding of individual lightweight work blanks from a feed chute of a thread rolling machine to a work station between relatively movable thread rolling dies and comprising a frame, a starter mechanism operatively mounted on the frame and including drive means and a starter assembly, the starter assembly having a movable starter blade for movement in opposite directions toward and away from a starting position at the work station, the drive means including a pivotable crank rotatably supported on the frame and engageable with the starter assembly for pacing movement of its starter blade, the pivotable crank providing a one-way drive to retract the starter blade away from its starting position upon rotation of the crank in one angular direction, the starter assembly further including a starter blade supporting arm cantilever mounted at one end on the frame with an opposite free end supporting the starter blade for movement toward and away from its starting position at the work station, the arm being resiliently biased to urge the starter assembly toward engagement with the pivotable crank for effecting a following return motion of the blade toward its starting position, upon rotation of the pivotable crank in the opposite angular direction, and for providing a preselected starting force on each work blank to wedge it between the thread rolling dies.

2. The starter mechanism of claim 1 wherein the drive means includes a drive actuating cam and cam follower linkage mounted on the frame, the cam follower linkage connecting the cam to the pivotable crank, and adjustment means in the cam follower link- '6 age for varying the extent of retraction of the starter blade from its starting position without varying the throw of the drive actuating cam.

'3. The starter mechanism of claim 1 wherein the bladesupporting arm is formed of a flat strip of spring material, and wherein the resiliency of the spring material itself urges the starter blade toward its starting position and supplies the preselected work blank starting force.

4. The starter mechanism of claim 3 wherein the starter blade is mounted on one surface of the blade supporting. arm, and wherein the starter assembly further includes a spring member engaging a surface of the blade supporting arm opposite its surface on which the starter blade is mounted to provide a desired spring loading, for effecting the preselected work blank starting force urging the starter blade toward its starting position, upon straining the blade supporting arm when driven by the pivotable crank in a direction away from the work station.

5. The starter mechanism of claim 4 wherein the spring member is a flat strip of spring material having one end mounted on the frame in lapping relation to said one end of the blade supporting arm and disposed in coextensive supporting relation along at least a portion of the length of the blade supporting arm.

6. The starter mechanism of claim 3 wherein the starter assembly further includes an L shaped mounting plate having first and second legs in substantially perpendicular relation to one another, the first leg being fixed on the free end of the blade supporting arm in generally parallel relation thereto, the second leg projecting toward the work station, the starter blade being secured to the second leg of the mounting plate.

engagement therebetween.

Claims

2. The starter mechanism of claim 1 wherein the drive means includes a drive actuating cam and cam follower linkage mounted on the frame, the cam follower linkage connecting the cam to the pivotable crank, and adjustment means in the cam follower linkage for varying the extent of retraction of the starter blade from its starting position without varying the throw of the drive actuating cam.

3. The starter mechanism of claim 1 wherein the blade supporting arm is formed of a flat strip of spring material, and wherein the resiliency of the spring material itself urges the starter blade toward its starting position and supplies the preselected work blank starting force.

4. The starter mechanism of claim 3 wherein the starter blade is mounted on one surface of the blade supporting arm, and wherein the starter assembly further includes a spring member engaging a surface of the blade supporting arm opposite its surface on which the starter blade is mounted to provide a desired spring loading, for effecting the preselected work blank starting force urging the starter blade toward its starting position, upon straining the blade supporting arm when driven by the pivotable crank in a direction away from the work station.

6. The starter mechanism of claim 3 wherein the starter assembly further includes an ''''L'''' shaped mounting plate having first and second legs in substantially perpendicular relation to one another, the first leg being fixed on the free end of the blade supporting arm in generally parallel relation thereto, the second leg projecting toward the work station, the starter blade being secured to the second leg of the mounting plate.

7. The starter mechanism of claim 1 wherein the frame provides a fixed stop, wherein the free end of the arm carries a movable stop thereon engageable with the fixed stop, and wherein adjustment means is provided for one of the fixed and movable stops to vary the engagement therebetween.