US3219371A

US3219371A - Die post construction

Info

Publication number: US3219371A
Application number: US276799A
Authority: US
Inventors: James C Danly
Original assignee: Danly Machine Specialties Inc
Current assignee: Danly Machine Specialties Inc
Priority date: 1963-04-30
Filing date: 1963-04-30
Publication date: 1965-11-23
Anticipated expiration: 1982-11-23

Description

I 1965 J. c. DANLY 3,219,371

DIE POST CONSTRUCTION Filed April 50, 1963 2 Sheets-Sheet 1 144%, MMWI/VJWW A-rTvs.

United States Patent 3,219,371 DIE POST CDNSTRUCTION James C. Danly, River Forest, 111., assignor to Danly Machine Specialties, Inc., Chicago, 11]., a corporation of Delaware Filed Apr. 30, I963, Ser. No. 276,799 2 Claims. (Cl. 287-20) The present invention relates to guide posts for die sets and more particularly to posts of the readily insertable and readily removable type.

To insure precise spacing and parallelism, guide posts in the conventional die sets are press fitted into deep bores formed in the die shoe. Securing a deep interfering fit requires exerting high pressure during installation and removal, pressures which may be on the order of 3-15 tons so that an hydraulic press is usually employed. While efforts have been made in the past to provide for easy replacement of die posts, this has generally been accompanied by sacrificing the operating characteristics, specifically the ability of the post to Withstand high, unbalanced, i.e., cantilevered, load forces without acquiring a set. Where the posts acquire an angular set with respect to the die shoe, the die set surfaces are no longer perfectly parallel and difiiculty may be experienced in removing and installing the upper die set member.

Accordingly it is an object of the present invention to provide a guide post construction which is capable of quick and easy insertion and removal but which is nevertheless highly resistant to the effects of unbalanced loading so that the spacing and parallelism of adjacent die posts is maintained with a high degree of accuracy under all conditions which may be encountered in use. It is another object to provide a guide post construction in which the guide post may be almost fully inserted and fully withdrawn by hand and which has an interfering fit portion which occupies only a small portion of the total depth of the bore or socket. It is another object to provide a guide post construction having novel clamping means for insuring that reference surfaces are maintained in engagement and in which the clamping means may be employed to draw the post over the final portion of its seating movement.

In one of the aspects of the present invention it is an object to provide a guide post construction having a novel threaded arrangement for anchoring the post with respect to the die shoe which may be employed both for drawing the post into final seated position and for lifting the post when replacement becomes necessary or desirable. In this connection it is an object to provide a guide post construction which enables easy insertion and removal of the post, with removal being conveniently accomplished from the top of the die shoe in installations where the underside of the die shoe is blind or must remain seated.

Finally it is an object to provide a removable guide post which is economical, easy to install, and which is capable of many insertions and withdrawals without loss of effectiveness.

Other objects and advantages of the invention will become apparent upon reading the attached detailed description and upon reference to the drawings in which:

FIGURE 1 shows a guide post constructed in accordance with the present invention in its seated working position.

FIG. la is an enlarged fragmentary section with clearance fit shown exaggerated.

FIG. 2 is a top view corresponding to FIG. 1.

FIG. 3 shows initial insertion of the post.

FIG. 4 is a fragmentary view showing the use of the clamping bolts in drawing the post home.

FIG. 5 is a view similar to FIG. 1 but showing an alternate construction and taken on line 55 in FIG. 6.

FIG. 6 is a top view corresponding to FIG. 5.

FIG. 7 shows use of the clamping bolts for drawing the post into seated position.

FIG. 8 is a fragmentary view showing the nut turned to bottoming position prior to back-off.

FIG. 9 shows use of a flange for jacking the post from the hole in the die shoe.

FIG. 10 is a top view corresponding to FIG. 9.

While the invention has been described in connection with certain preferred embodiments, it will be understood that I do not intend to be limited to the embodiments shown but, on the contrary, I intend to cover the various alternative and equivalent constructions included within the spirit and scope of the apepnded claims.

Turning now to the drawings there is disclosed in FIG. 1 a die post 20 constructed in accordance with the present invention having an elongated cylindrical shank 21 and a relatively shorter cylindrical base 22. Integrally formed on the post is a flange 23 having a shoulder 24 and a seating or reference surface 25. The guide post is received in a die holder on shoe 30, only a portion of which is shown having a bore or socket 31 and an upper surface which includes an annular land 32 surrounding the bore.

In carrying out the present invention the base 22 of the guide post is so dimensioned with respect to the bore as to provide an interfering fit over a small, final portion of the axial insertion stroke while having a clearance fit over the remainder of its stroke enabling the post to be almost fully inserted by hand, or with only application of light pressure, and finally pressed into seated engagement. Further in accordance with the present invention, a threaded clamping means is provided for acting upon the flange for drawing it down into a final bottomed or seating position on the land and for maintaining contact between the flange and the land even in the face of high cantilevered loads applied to the shank of the post. Thus in the present instance I provide immediately adjacent the underside of the flange on interfering fit portion or band 35 having a diameter d which slightly exceeds that of the diameter d of the bore. This interfering fit distance 35 preferably extends for a distance which is short as compared to the diameter of the post. Preferably the length, indicated at L lies Within the range of about 0.10 to about 0.25 of the diameter d Thus in the case of a practical post having a base diameter of about 1%", the band of interfering fit may be approximately A to A1". The remainder of the base length has a clearance fit with respect to the bore, the clearance being indicated at 37 in FIG. 1:1. If desired, a slight undercut may be taken adjacent the seating surface 25 on the flange as indicated at 38.

For the purpose of maintaining the flange surface 25 seated on the land, and for use in drawing the members together after the post has been inserted as far as pos sible by hand, a threaded clamping means is provided having a suflicient take-up or throw so that an appreciable portion of the thread may be engaged, to develop strength, before the take-up or clamping pressures are exerted. Thus in the preferred embodiment I provide

toe clamps

41, 42, 43 (see FIG. 2) equally spaced about the posts fitted with

screws

45, 46, 47 engaging registering tapped holes 48 formed adjacent the land 32 on the die shoe. The holes are preferably equally spaced from one another and equally spaced from the post axis.

In a typical installation the post 20 is hand inserted as shown in FIG. 3 to the point, FIG. 4, where the interfering fit portion 35 begins to engage the bore. Following this, a pressure ring 56 having a central opening 51 and peripheral openings 52 is slipped over the guide post and the machine screws 45, 46, 47 are inserted, the screws being sufliciently long so as to engage at least a few of the threads in the tapped holes 48 in the shoe by the time the parts come into interference Subsequently the

screws

45, 46, 47 are rotated in sequence by a suitable wrench, a few turns at a time, drawing the post down until the surface 25 of the flange is firmly seated on the land 32 of the die shoe. The screws are then unscrewed and the pressure ring 50 is removed, to be replaced by the

toe clamps

41, 42, 43, following which the screws are inserted and retightened. It will be apparent that if desired the pressure ring 50 may be left permanently installed and used in lieu of the toe clamps. The toe clamps have the advantage of taking up less space.

While screws assisted insertion over the pressure fit portion of the fitting stroke has been described above, it will be apparent that as far as post insertion is concerned, a lead mallet or the like may be used to drive the post home, with the screws being utilized to subsequently hold it in place in spite of unbalanced loading. The holding or prestress force may be about 500 to 3000 lbs.

When the time comes to remove the post, the clamping screws are first removed, along with their toe clamps, the die shoe is inverted and the post is pounded or pressed out from the underside. Because of the small amount of total area in interfering engagement, relatively light forces are required for removal and the post need only be moved a short distance corresponding to the axial length of the interfering band.

The construction described above is preferred since it is inexpensive and takes up minimum space producing little or no conflict with the installed dies. However, where the underside of the die shoe is necessarily ob- Structed or blind the present invention may be applied to a somewhat modified construction shown in the remainder of the figures and which enables the posts to be easily pulled from, rather than driven from, the bores in the die shoe. Thus, in accordance with one of the aspects of the invention I provide a die post construction which includes a. nut having a threaded engagement with the flange which serves not only to maintain the flange seated in the face of unbalanced loading but which permits purchase of a suitable wrench so that when the nut is turned the post is jacked out of its seated position. Further in accordance with the present invention the axial throw of the thread between the nut and flange is made sufficiently long so as to exceed the axial distance of the interfering fit portion so that the post may thereafter be removed from the bore by hand. Because of the similarity of the two constructions the same reference numerals will be employed, where applicable, with a subscript a.

Thus, the guide post indicated at 20a includes an elongated shank portion 21a and a cylindrical base portion 22a with an integral flange 23a in between having a seating surface 25a on its underside. The die shoe a has a bore 31a surrounded by a land 32a which is precisely at right angles with respect to the bore. Formed on the base of the post is a band 35a of interfering fit, the remainder of the base having a free or clearance fit.

In carrying out the invention a nut 41a is provided having a threaded connection 42a with the outside surface of the flange, and registering holes are provided in the nut for reception of clamping

screws

45a, 46a, 47a. Operation may be understood by referring to FIGS. 7 and 8. Thus, with the nut 41a slightly unscrewed, as in FIG. 7, the clamping screws are inserted into the holes in the die shoe and turned in succession until the flange is firmly seated on the land. Following this, the screws are temporarily removed and the nut is turned until it is bottomed on the land as shown in FIG. 8. For the purpose of insuring that the force is concentrated at the flange, and not on the nut, the nut is then turned backward a portion of a turn until the holes in the nut register with the holes in the die shoe, following which the clamping screws are reinserted and turned tight as shown in FIG. 5. Thus the nut clearance, indicated at 43a in FIG. 5, is intentional, and the nut simply serves to apply axial force, all of which must be borne at the region of flange-to-land contact.

For the purpose of removing the post a wrench is provided in the form of a capstan tool 60 having dowels 61, 62 which register with the screw openings. The screws are removed and the wrench is inserted as shown in FIG. 10. Swinging the wrench clockwise causes the nut to crowd downwardly against the land surface with upward reaction against the thread on the post, lifting the post clear of the interference band while the threads are still in engagement. The post may be lifted by hand the rest of the way and the nuts removed.

Since the interference band is relatively narrow and concentrated at the top of the cylindrical base in both the versions described above, comparative tests were made with a conventional guide post having a flange and the usual, extensive interfering fit. The posts were cantilever loaded by a force of 1000 pounds applied near the ends, a loading which may be encountered during rough usage, and the amount of resulting angular set was measured. It was found that the present guide post construction suffered substantially less set than the conventional flanged post, an amount so small that it was not measurable. Thus, in the case of the conventional post, it was noted that after application of load a crack of light could be seen between the flange and the flange surface indicating poor recovery from load. The present construction, being distinguished by a flange which is prestressed against the land showed complete recovery. It will be apparent to one skilled in the art that before any separation can take place at the land surface of the present construction, the clamping force, or prestress, must be exceeded, which will not occur even in the face of substantial unbalanced loading. Thus it is seen that the present construction overcomes the disadvantages associated with the use of flanges on conventional guide posts. Because of the length of the base and the fact that primary reliance is placed upon the stressed flange to maintain perfect uprightness, any theoretical play over the major portion of length of the base does not involve any sacrifice of stability, recovery, or ability to withstand heavy off-center loads.

The exact tolerances to be employed to practice the present invention keeping the above description in mind will be apparent and a matter well within the skill of the art. In the case of a practical guide post having a base diameter of a nominal 1%", the tolerances may be as follows: The interfering portion may have a tolerance of 1.2512" to 1.2509", being ground to final dimension. The clearance fit portion may have a tolerance of 1.2502" to 1.2499". The bore in which the base is to be received may have a tolerance of 1.2510" to 1.2502" with the final dimension being achieved by broaching or the like.

It is found that hand start and clearance fit avoids the usual problem of cocking and initial line-up. Moreover, tests show that the present post may be repeatedly inserted and withdrawn, up to times or more, without sacrifice of holding power. It will be apparent that the construction is economical, considering the many advantages which it offers, and that a post may be constructed, particularly in the versions set forth in FIGS. 1-4 at a cost which is substantially the same as posts of conventional, nonreadily removable type.

The term maintained in contact used in the claims is intended to refer either to the ability to maintain contact during application of the unbalanced loading or to the ability to reestablish contact, i.e., to avoid set, after the load is released. Which of these two actions occurs depends upon the amount of clamping or prestress.

I claim as my invention:

1. Ina die set construction the combination comprising a die holder having an upper surface and a bore at right angles thereto, the upper surface forming an annular land about the periphery of the bore, a guide post having a flange formed integrally thereon serving to divide the post into an upper shank portion and a lower cylindrical base portion, the flange having a flat undersurface for seating against the land when the base portion of the post is fully inserted in the bore, the base portion of the post having clearance with respect to the bore over the major portion of the length of the base portion and having a narrow cylindrical collar surface of slightly greater diameter at the upper end of the base portion adjacent the flange so that the base portion may be almost fully inserted by hand into the bore up to the point where the collar surface engages the hore, and clamping means engaging said flange for applying clamping pressure to the flange at points distributed substantially equiangularly about the periphery thereof and including threaded elements engaging the die holder for drawing and pre-stressing the flange tightly against the land to insure maintenance of seating contact between the flange and the land even in the face of high unbalanced cantilever loading of the shank.

2. In a die set construction the combination comprising a die holder having an upper surface and a bore formed therein perpendicular to the upper surface and with the upper surface serving as an annular land surrounding the bore, a guide post having an integral flange projecting radially outward near the lower end thereof defining cylindrical base and shank portions, the flange having a flat undersurface which is perpendicular to the axis of the post for flatly seating on the land when the base portion of the post is fully inserted in the bore, clamping means for engaging the flange, said clamping means including threaded fasteners engaging the die holder at points spaced substantially equiangularly about the land, the base portion of the post having a clearance fit with respect to the bore over the major portion of the insertion stroke to permit hand insertion over such major portion but said base portion and said bore being relatively dimensioned to provide a narrow band of interference fit which is engaged during the final short portion of the insertion stroke, the axial throw of the threaded fasteners being in excess of the length of the short final portion of the stroke so that turning of the threaded fasteners causes axial pressure to be brought to bear upon the flange for moving the flange into seated engagement against the land and for pre-stressing the flange to insure maintenance of seating contact between the flange and the land even in the face of high unbalanced cantilever loading of the shank.

References Cited by the Examiner UNITED STATES PATENTS 2,322,422 6/ 1943 Danneman 287-20 2,356,387 8/ 1944 Danneman 28720 2,363,041 11/1944 Boye 287-20 2,714,422 8/ 1955 Janiszewski 287-203 3,058,764 10/ 1962 Scott et al. 287-203 CARL W. TOMLIN, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 219,371 November 23, 1965 James C. Danly It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the grant, line 3, and in the heading to the printed specification,

lines

4 and 5, for'a corporation of Delaware", each occurrence, read a corporation of Illinois Signed and sealed this 7th day of June 1966.

(SEAL) Attest:

ERNEST W. SW'IDER Attesting Officer Commissioner of Patents EDWARD J. BRENNER

Claims

1. IN A DIE SET CONSTRUCTION THE COMBINATION COMPRISING A DIE HOLDER HAVING AN UPPER SURFACE AND A BORE AT RIGHT ANGLES THERETO, THE UPPER SURFACE FORMING AN ANNULAR LAND ABOUT THE PERIPHERY OF THE BORE, A GUIDE POST HAVING A FLANGE FORMED INTEGRALLY THEREON SERVING TO DIVIDE THE POST INTO AN UPPER SHANK PORTION AND A LOWER CYLINDRICAL BASE PORTION, THE FLANGE HAVING A FLAT UNDERSURFACE FOR SEATING AGAINST THE LAND WHEN THE BASE PORTION OF THE POST IS FULLY INSERTED IN THE BORE, THE BASE PORTION OF THE POST HAVING CLEARANCE WITH RESPECT TO THE BORE OVER THE MAJOR PORTION OF THE LENGTH OF THE BASE PORTION AND HAVING A NARROW CYLINDRICAL COLLAR SURFACE OF SLIGHTLY GREATER DIAMETER AT THE UPPER END OF THE BASE PORTION ADJACENT THE FLANGE SO THAT THE BASE PORTION MAY BE ALMOST FULLY INSERTED BY HAND INTO THE BORE UP TO THE POINT WHERE THE COLLAR SURFACE ENGAGES THE BORE, AND CLAMPING MEANS ENGAGING SAID FLANGE FOR APPLYING CLAMPING PRESSURE TO THE FLANGE AT POINTS DISTRIBUTED SUBSTANTIALLY EQUIANGULARLY ABOUT THE PERIPHERY THEREOF AND INCLUDING THREADED ELEMENTS ENGAGING THE DIE HOLDER FOR DRAWING AND PRE-STRESSING THE FLANGE TIGHTLY AGAINST THE LAND TO INSURE MAINTENANCE OF SEATING CONTACT BETWEEN THE FLANGE AND THE LAND EVEN IN THE FACE OF HIGH UNBALANCED CANTILEVER LOADING OF THE SHANK.