US2987348A - Bearing retainer-indexing means for antifriction die sets - Google Patents

Description

June 6, 1961 w. J. BLAZEK 2,987,348

BEARING RETAINER-INDEXING MEANS FOR ANTIFRICTION DIE SETS Filed Feb. 26, 1959 WILLIAM J. BLAZEK BY-CORBETT. MAHONEY,

MILLER & RAMBO,ATT Y5.

United States Patent Ohio Filed Feb. 26, 1959, Ser. No. 795,803

' 2 Claims. (Cl. 308-6) This invention relates to bearing-retainer indexing means for antifriction die sets. More particularly, it relates to indexing means for the relatively axially movable bearing retainer, guide post, and guide bushing of the die sets of punch presses and other reciprocating machine tools.

The present invention is an improvement over the structure disclosed in the patent to Blazek et al. No. 2,846,278 which issued August 5, 1958, and especially over the structure disclosed in FIGURE 7 of such patent.

The present invention aims primarily to provide position-maintaining means for the movable bearing retainers of antifriction die set guiding and aligning devices. Such devices are formed customarily so that apunch-carrying movable holder of a die set is provided with guide posts which are axially receivable for relative longitudinal movement in longitudinal holes or bores of stationary bushings carried by a complemental die holder of the set. In association with these parts, tubular ball-bearing retainers of the movable floating type are arranged and held so that ball elements carried thereby are disposed in annular receiving spaces provided between the outer wall surfaces of the posts and the adjacent inner wall surfaces of the bushing bores, the ball elements being disposed in simultaneous contact with post and bushing surfaces.

This construction is such as to provide for accurately guided and confined reciprocatory movement on the part of the die and punch-supporting holders of a die set. The construction eliminates undesired lateral motion between parts and enables the punch and die members of the set to be brought into and out of true forming contact with work pieces positioned between the same in the press. Such alignment of the relatively movable die and punch members is made possible through the use of said ball element guide devices, and results in prolonging the working life of the punch and die members, as well as enabling the same to produce more rapidly and accurately forming operations on work pieces. Such pressure-loaded ballbearing guiding devices for die sets are disclosed, for example, in the prior patent to Conner No. 2,422,774 granted June 24, 1947.

In this type of die set guide apparatus, upon the movement of the posts into the adjacent ends of the bushing bores, the outer cylindrical surfaces of the posts engage the ball elements of the retainers and force the same against the complemental inner cylindrical walls of the associated bushing bores. Since the diameter of each ball element of the bearing retainers is such that it exceeds slightly the width of the annular spaces which the retainers occupy, each ball element so positioned is placed under compression by its confined engagement with adjoining post and bushing surfaces. Such loaded or pressure engagement of the ball elements causes the retainers to move linearly with the associated movable posts but at a relatively reduced or lower rate of travel. It is important, therefore, in the proper functioning of each guide that the floating bearing-retainers move at a controlled rate concomitantly with the posts in providing antifriction guidance, whereby to minimize wear and maintain positive alignment between the relatively movable die set parts. r

Because of the floating characteristics of the ballbearing retainers, that is, the absence of any direct physiice cal connection between the retainers and associated posts and bushings, it has been somewhat diflicult for machinists to so assemble each guide and dispose the retainers so that the bearing elements thereof will maintain their pre-loaded positions throughout full back and forth stroke movements of the guide assembly. If, for example, a retainer should fail to move with its reciprocatory posts, excessive friction, part wear and looseness would develop rapidly and impairment and loss of guiding function of the guide assembly would take place.

According to said Patent No. 2,846,278, there was provided-positioning means for use in association with such antifriction guide appliances for die sets, whereby in assembling the parts thereof it was necessary to arrange the parts of the guide assembly in their proper or required relative order in the resulting assembly. Furthermore, this positioning means maintained the retainers properly interposed between the posts and bushings in all their working positions and served during active cooperation thereof to preclude movement on the part of said re-- tainers to positions in which all the antifriction bearing elements positioned therein would be removed from simultaneous pressure engagement of associated posts and bushings. 1

The present invention relates particularly to a structure in which the guide bushings are disposed on the upper die holder and the guide posts are located on the lower die holder with the posts and bushings movable relative verti-- cally during the working stroke of the die members, as disclosed in FIGURE 7 of said Patent No. 2,846,278. However, the indexing and retaining means of this present invention is an improvement over the means for fioatingly suspending the retainer in an initial predetermined posi-.-

tion from the associated bushing of each antifriction guide assembly. 1

- Additional objects, advantages, structural and operational features will be apparent from the following tie-=- along line 2-2 of FIGURE 1 through one of the guide assemblies. I

FIGURE 3 is a horizontal or transverse sectional view taken alongline 33 of FIGURE 2.

With reference to the drawing, relatively movable dieholders 10 and 11 of a die set are shown and are provided with one or more antifriction guide assemblies 12, two being shown as an example. Theassemblies 12 are employed for maintaining the holders 10 and 11, and parts carried thereby, in proper alignment or position of relative registry during working movements of a punch press, or other machine tool, on which such a die set is mounted.

Each assembly 12, according to this invention, comprises a cylindrical bushing 13 rigidly carried by and depending from an opening formed in the die holder 10 of the die set. The bushing provides an internal cylindrical mensional limits by machining and otherwise finishing and hardening the same to a true cylindrical contour. 'Ih e member 19 is illustrated as a downwardly movable memher and the member 11 is illustrated as a stationary member but this relationship may be reversed or, in fact, both Patented June 6,1961,

members may be movable since it is the relative movement that is important.

Mounted for axial movement in each guide assembly is a tubular, sleeve-like, bearing retainer 16. Each retainer I6 -is' formed witha plurality of" transve'r'se'- relatively spaced openings- 17 constituting sockets-for therotatable' retention of -a plurality of ball-bearing elements 18, these openings being shown arranged invertically-spacedhorizontal rows but otherarrangements are possible} The wall thickness of each retainer 16is1es's than theradial' width of an annular space 19 formed between each inter fitting set of guide bushings 13 andjpo'sts 15 (FIGURES) when they are disposed in' relatively telescoped relationship. Each bearing element 18; however, possesses adiameter slightly greater than the'radial width of the space 19 receivingthe same; This enlarged diameter is important'in'theoperation of a guide assembly of this'nature,

in that when abushing-13'and "a post 15 move axially into telescoping relationship and an associated retainer 16 simultaneously moves axially therebetween, the ball-bear ing= elements will'becrowded between the'post'15 and the bushing 13 to place the engaged ball elements 18 under compressive forces. The ball elements 18 so engagedare" rotated, with the resultthat the retainer 16 moves axially concomitantly with the relatively moving post 15 and'th'e bushing 13 but at a lower rate of linear travel. Such relativeaxial motion of the'post 15, the bushing 13, and the retainer 16, is continued as the ball elements 18 are progressively engaged between the post and bushing producing a positive guiding. action wherein lateral motion is eliminated and accuracy thereby obtained in punch-and die registry;

According to the present invention, there is provided the indexing and positioning means illustrated best in FIG- URES 2"and' 3.

the=lowerend of the bushing audits other-half depending from the'bushing, at the time the post 15 and the bushing 13 are out of operative relationship prior to the beginning of the working stroke of the press; as shown in'FIGURE 2. However, other indexedrelative positions are possible. Thi'smeans comprises rneans-for splining the retainer to thebushing-and includes a grooved keyway or'slot 25 which is formed in the inner-surface of thebore -14of thebushingISand extends the full length thereof being open at-eachend at the corresponding extremity of the-bushing. For cooperating with this keyway slot 25, a keyis pro vided and may be in the foi'm-of a'suitable stopdevice-but is shown as a stud 26 which is-fixed inan opening 27 ad jacent the upper end' of 'the'retainer'16 and-extends radially outwardlyinto theslot -25 with-clearance-between"its;

c. a a 55 Figure 3, clearance isprovided at the sides of the stud and theadjacent sides of the slot by having the studof outer end the bottom" of ftheslot. Also,-'as indieatedin less diameter than the slot; To limit downward movementor dropping of the retainer 16 out of the bushing 13,

an abutmentof suitable form is provided and is shown as'a stop pin or stud 28 in thekeyway slot 25 at a suitable location. This'stud 28 isfixed in an opening 29 in the bushing 13 which communicates with the'slot 25 and the stud'28 extends radially inwardly into the groove but terminates short-of the-inner surface of the bore 14. As

the retainer 16 is moved downwardly in the bushing 13 by gravity, the stud 26 will'engage the stud 28 and 'fl'oating'ly'" suspend the-retainer from'the lower end of the bushing'13;

However, the 'retainer'will be so'suspended that it can'pbe moved upwardly within'the bushing 13.

V In the initial assembling'oftheretainer 16 withinthe bushing 13, in the example shown, the studf28fwill be located to suspend the re'tainer16'with about half its lengthfdepending from the bushing 13am its other half l telescoping'upwardly'thereinj However, one orm'ore I drop the retainer 16 into the bushing 13 and to thereby 4 t additional openings 29a may be provided in bushing 13 to position the stud 28 at a difierent location along the bushing and one or more additional openings 27a may be provided in the retainer 16 to position the stud 26 at a different location, to index the bushing 13 and post 15 as desired. The retainer 16'can-be' dropped within the bush ing 13' until the" stud"26carried'thereby engages-thestop pin 28 carried "by thebushin g' 13 This relationship will be maintained until" the" die or punch" holder'10 moves downwardlysuificiently to cause the post 15 of each assembly 12 totelescope the'lower end of the bushing of that assembly. Continued'downward movement of the bushing 13 in the working stroke of the press, in the example' sh'own; w'illcaus'e' thebushing 13 and the post 15 to tel'escope beyondthe relative position shown in FIG- URE '2 and the balls '18 of the retainer which are therebetween will be positively rotated and placed under compres sion 'by the relatively axiailyrmoving bushing and post.

The positive rotation thus imparted to the compres sively loaded ball elements 18 causes the retainer 16 to descend 'v'v'itlfthe bushing- 13 and move downwardly along the post' 15but 'ata lower rate of travel, which will, in

fact, be substantially one half the rate of-the'downward movement ofthe bushing 13 over the post 15 During upward movement' 'ofthe bushing 13; a reverse action will take place 'untiI'the position shown" in' FIGURE 2"is' reached atwhichtime; the retainer'16 willagain be floatin'g'ly suspendedf from *the bushing" 13 'by means of"en-' agenient of thepin 28 with the pin 27.

' Through the u'se' 'of'the indexing and positioning means describei the vertically movable ball bearing-carrying retainerorsleeve"'member 16 ofan antiirictiondie set guide assembly is supported or retained against downward movement in 'a' redetermined position relative to the as sociated movabl'e b'iishing 13 and "stationary 'post' 15' of thegu'ide assembly. "Furthermore, the construction of the positioning mean's' ot-the-"present invention is such that the retaine supporting function'of the -bu'shing"13 is re leased' or e ved '-aut'omatic'ally' with the descent of the bushingbn r V w be caus'ed POSIfiV'QlY to move linearly with the associated movable bushing at a controlled relative rate of travel throughout the full working stroke of the movable die holder-10 'Whenthe-Iafter'returns to its normal 'or starting-positlon' and re'turns the-bushing lli to such position, the retainer member-M returns with it and occupies a predetermined position'relative thereto.- At this time, the ball el'einritsj'lS 'of'the'ret'ainer'me'mber 16 are relieved of the compres ive'rorce's' resulting from their simultaneouscontact with contiguous surfaces of the movable and stationary guid members --13 Y and 15 "during a working stroke" and the interposition of the retainer member;16- with its'ball elemefit's 18} enables the "retainer member 16' to be'movably positioned-in its establishdrelation'with'said 'guide mem bars." The re'ta'iner '16, itwill be observed, moves in unison withtheassociated bushing 13'when' the bearing elernnts '18 are' unloadeidg but when said'elernents are loaded or pressure 'confiried b e'twe'en the post" 15 and the bushing 13; "the bushirig carriedretfiner holding or indexing means isrereased td admit ofindependentr'elative movement of thefret'ain'r 16 with rspect'td'theb1ishing- 13. i

. The indeiii'lg means" extreme1y"=sim 1e and inexpensiv'e niea n very ene'ctiv in themamteriinqica ed:above." sincenie eyway orator zsextends 'thefull-lengtli of the bushing F13, it ma y be refined therein by simple and inexpensivejoperation'si' Furthermore, the stopmembers or devices26 and 2'8 providef ;simplebut positive stop means for "suspe'r'rding' the retainer 16finlfa predetermined positi'on relative to the bushing 13. Iris simple to locate the stop'meninerszeandzsjinpredetenninedfixed ldbfations on the respective membe'r'sls 'and'l6 and to'thenfiirely' working stroke; "so that the retainer 16"will' embers 13 'and 15; res ectively; of the as-" sembly' 12? The telescopie relation between the "guide ment of the stop 26 with the stop 28. Furthermore, as pointed out above, the positions of these stops may be varied as desired to selectively position the bushing 13 and the retainer 16.

According to the provisions of the patent statutes, the principles of this invention have been explained and have been illustrated and described in what is now considered to represent the best embodiment. However, it is to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

Having thus described this invention, what is claimed is:

i. In a die set; upper and lower die-supporting members relatively movable toward and from one another; a tubular bushing carried by the upper of said members and having an inner surface formed with a longitudinally disposed groove; a guide pin carried by the lower of said members in telescoping, axial alignment with said bushing; a ball-bearing retainer positioned between said pin and bushing; a stop device carried by and projecting outwardly from said retainer and into the groove of said bushing, said stop device being slidable longitudinally within the groove of said bushing; and abutment means carried by said bushing and engageable with said stop device for indexing said retainer in a preselected position with respect to said bushing, said stop device being adjustable to difterent, axially spaced positions on said retainer so as to vary the indexed position of said retainer with respect to said bushing.

2. In a die set; upper and lower die-supporting members relatively movable toward and from one another; a tubular bushing carried by and depending from the upper of said members and having an inner wall surface formed with a longitudinally extending key way; a guide pin carried by and projecting upwardly from the lower of said members in telescoping, axial alignment with said bushing; a ball-bearing retainer movably carried between said pin and bushing; and a pair of relatively engageable stop devices carried respectively by said bushing and said retainer and extending into the key way of said bushing and operable upon relative engagement to maintain said retainer in a preselected position relative to said bushing and to preclude withdrawal of said retainer from the lower end of said bushing, said stop devices being relatively adjustable longitudinally of said key way to vary the preselected position between said bushing and said retainer.

References Cited in the file of this patent UNITED STATES PATENTS 2,422,775 Conner June 24, 1947 2,774,430 Blazek Dec. 18, 1956 2,846,278 Blazek Aug. 5, 1958

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