US1921421A - Removable guide pin - Google Patents

Description

Aug- 8, 1933. 5 us 1,921,421

REMOVABLE GU IDE P I N Filed Dec. 12. 1931 Ja 5 28 29 A 25 26 I 29 INVENTOR.

MzwmanM..Marsil ius BY A TTORNE Y 25mm) MM P'atentecl Aug. 1933 UNITED STATES PAT REMdVABLE GUIDE PIN Newman Marsilius, Bridgeport, Conn, assigner to The Producto Machine Company, Bridgeport, Conn., a Corporation of Connecticut Application December 12,1931. Serial No. 580,724

r 4 Claims. (01. zen-20 sets, to grind, the dies secured in the die-sets,-

which necessitates the removal of the dies from the die-sets and the. consequent detachment of the guide or liner pins, so these pins necessarily have to be made detachable'and adapted 'to be again positioned in the die-set bed when the dies have been sharpened andplaced back in the die-sets. It is obviously important .that a convenient and firm means of detachably securing these pins in the die-set base be provided so that the pins will remain, in position; 7

I have therefore provided-an improved pin fastening means that may obviously be used to advantage for detachably fastening pins in parts other than the sets and which-comprises a pin having an expandible cylindrical lower split end portion for insertion in the hole of the base of the die-set, whichis hollowed out and split in three like sections to insure a uniform bearing of the'pin on all sides of the hole in the-bed, and to employ a hardened taper camin this split cylindrical end of the'pin forexpanding the sections and to keep them inplace. This floating camis looselyheld in the hollow end of the pin in a way to engage the walls of the pin when rotated therein. This cam hasthree longitudinal high points to engage three corresponding longitudinal lobes formed on the inner walls of the expanding sections, and includes a shouldered socket to receive awrench whereby the cammay be turned within the expanding sections. Whatever pressure is exerted to bind the pin in the die holder will be the necessary binding action'induced by thegenerated movement of the cam. Wherever the cam binds it will positively hold at that position becauseof the rise in the cam surface.

.A further and important object of the invention isto provide means for causing a more uniform engagement of that much of the surfaces of the expandible sections as is positioned within the hole of the die-set, in a manner to prevent the pin from shaking loose, with the operation of the dieset as is frequently the case when but a limited area of the connected parts are engaged. This more complete engagement is obtained by forming the engaging surfacesof the pin and hole of varying diameters, and tapering the cam to operpointed out in the claims.

ate therein, that is, making one slightly larger at one end than the other.

- Withthe above and other objects in view, an embodiment of the invention is shown in the accompanying drawing, and this embodiment will be hereinafter more fully described with reference thereto and the invention will be finally In the drawing:--' A Fig. 1 shows a perspective View of a die-set provided with two guide pins constructed in accordance with the shown in Fig. 2; the spring retaining ring being removed;

- Fig. 4 shows a detached plan view of an ex- ENT OFFICE] present embodiment of my invention;

pandible spring member employed'for retaining the rotatable cam within the cylindrical split end of the pin;

Fig.5 shows abottoin end view of the cam shown vin'li igs. 2, 3 and 6; and v Fig. 6 shows' a detached side elevation of the rotatable floating camemployed in the cylindrical split end of thepin, as shown in Fig. 2. The die-set'shown in Fig.1 comprisesa bed 10 to whichthe die, notshovvn, is attached. 11 represents the reciprocatable' and removable punch holderwhich carries the punches, not shown, to operate"in-the dies. 12 represents the guide pins two. of which are shown in this particular figure, secured in holes 130i the die bed for the purpose of'guiding the punch holder in its vertical reciprocatory movements with respect to the die bed in the operation of the die-set. The pins shown are obviously alike in construction and perform a like purpose; therefore the illustrations shown in the other figures of the drawing are representative of the two-pins shown. The guide. pin 12, see Fig. 2, is provided with a central longitudinal hole 14 designed in part to form an oil reservoir 15 for lubrication of the vertical reciprocatory movements of the punch holder member of the die-set. This upper or lubricant containing portion 15 of the central longitudinal hole is provided with an upper tapped end portion 16- and a lower tapped end portion 17, the former to receive an adjusting screw 18 and the latter to receive an adjusting screw 19 whereby the supply of lubricant 20 contained within the reservoir 15 is compressed and caused structure of each of the to work out through the lateral holes 21 and into the spiral groove 22 in the outer surface of the pin. A piston 23 is preferably used intermediate of one of these screws and the lubricant, and is provided with a spring 24 between it and the screw so that the lubricant can be retained under pressure owing to the yieldability of the spring and the adjustability of the screws. In this connection it will be understood that as the punch holder reciprocates up and down on the pins, heat is frictionally generated, causing the lubricant to warm up and expand through the small angular holes.

Several means are now employed for securing guide pins to the bed of die-sets which consist in part in forming a central pocket or opening in the lower end portion of the and splitting this hollowed end longitudinally, forming of it several expandible sections employing in connection therewith means for spreading these sections of the guide pin for engagement in the hole of a die bed. All or" these means, with which applicant is familiar, have the effect of spreading the lower end portion of such split end sections first, and in fact more than any other part of the sections, with the result that the pin engages the wall of the lower end or" the hole only, leaving that portion of the pin within the upper end of the hole more or less free and leaving the pin more liable to shake loose than if the engagement. were more uniform and extended throughout the depth. of the hole.

Therefore as a result of considerable experimenting, I have found that it is possible to obtain this uniform engagement of the split end of a guide pin with the hole of the bed, first by forming an elongated opening 25 in the lower end of the pin, which may be in alignment with the in bricant reservoir, and then splitting the said end longitudinally in three sections 26 and forming a longitudinal lobe 27 upon the inner wall of each section, and then employing in connection therewith a cylindrical form of rotatable floating cam 28 having correspondingly longitudinally disposed high cam surfaces 29 for engagement with the lobes, and to make this cam, including its high places, larger through its inner end 30 than its outer end portion so that the engagement and pressure of the cam, when rotated, will be first exerted against the upper or inner portions 31 of the sections where the resistance against expansion is naturally greatest. In order to facilitate this expansion and to irisure a 'uniform engagement, I have reduced the thickness of the upper portions of the walls of the sections just above the engaging pointsof the cam by forming an annular enlargement 32 of the opening 25, which is to insure greater flexibility.

In the illustrations of this application, I have exaggerated the amount of longitudinal taper of the cam since in practice but a few thousandths is necessary to accomplish my purpose, it being understood of course that the larger the pins the more taper required. This cam is cylindrical in form in that it has a central shouldered hole 33 to receive a wrench for tightening and loosening the cam which is purely a floating element that is retained within the opening when not in a tightened position by means of the spring ring 34 retained within the annular recess 35 formed in the inner wall of the lower portions of the sections.

I find that in practice it is equally practicable to obtain the desired results of my invention by longitudinally tapering the lobes on the inner walls of the sections instead of tapering the cam, and forming the cylindrical surface of the cam of a uniform diameter. In this case, the opening would be larger through its outer end portion than its inner end portion so as to insure engagement first of the inner end or the cam with the inner end portions of the lobes of the sections, as would be the case with the parts shown in the drawing.

Having thus described my invention what I claim and desire to secure by Letters Patent is:

1. The combination with a member having a cylindrical hole therein, a pin having a cylindrical end portion to iit said hole and a central opening in said end portion, radial slots also formed in said end portion and extending out from the opening forming flexible sections each having a longitudinal raised lobe formed on its inner surface, the upper end portions of the walls of said sections being thinner than the lower end portions, 'a rotatable floating cam in said opening having a series of longitudinally tapered ribs on its face to engage the length of said lobes, and means for rotatably supporting the cam within the opening;

2. A die-set for power presses including a bed having a cylindrical hole therein, a leader pin having a cylindrical end portion to fit said hole and having a central longitudinal cylindrical opening therein, radial slots also formed in said end portion, there being an enlargement of said opening above said slots forming flexible sections each having a longitudinal raised lobe formed on its inner surface, and a rotatable cam in said opening of substantially the length of said raised lobes and having a series of ribs on its face, higher on one end than the other. 7 V

3. A die-set'for power presses including a bed having a cylindrical hole therein, a leader pin having a cylindrical end portion to fit said hole and a longitudinal cylindrical opening therein,

and radial slots also formed in said end portion forming flexible sections each having a raised longitudinal lobe formed on its inner surface, an elongated expanding cam positioned in the opening and having awider inner end portion and an outer end portion, and adapted to be rotated within the open end of the pin in a way to spread the said sections to uniformly engage the walls of the hole.

4. A die-set for punching and forming presses, including a set member formed with cylindrical orifices, a cylindrical leader pin to fit one of said orifices and having a central bore and radial slots in the wall of its end portion forming flexible sections, each section having a longitudinal raised lobe on its inner face, an adjustable screw closing one portion of said bore above the sections, a rotatable floating cam positioned in said enlarged portion of the bore against said lobes and having a central longitudinal shouldered hole there'- through in 'line with said adjustable screw, whereby the expanding cam member may be engaged for rotation. l

NEWMAN M. MARSILIUS.

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