US2378603A

US2378603A - Punching apparatus

Info

Publication number: US2378603A
Application number: US486629A
Authority: US
Inventors: George F Wales
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-05-12
Filing date: 1943-05-12
Publication date: 1945-06-19
Anticipated expiration: 1962-06-19

Description

June 19, 19 45. WALES 2,378,603

PUNCHING APPARATUS Filed May 12, 1945 2 Sheets-Sheet 1 ATTORNEY Patented June 19, 11945 UNITED STATES PATENT. OFFICE PUNCHING APPARATUS George F. Wales, Kenmore, N. Y.

Application May 12, 1943, Serial No'. 486,629

26 Claim.

This invention relates to an apparatus for punching holes at specified locations throughout the areas of sheets of material suchas sheet metal, and is particularly adapted for punching the numerous rivet holes required in the thin metal panels or sheets which are used in aircraft construction to form the outer surfaces of wings, fuselages, and the like, but the invention may be applied to other uses where relatively large numbers of holes are required in panels or sheets of materials.

The main object of my invention is to provide an improved apparatus and method for punching holes in sheet materials, which is simple in construction, economical to manufacture and use, and efficient in its purpose and which can be made to operate on work sheets of any desired size.

Another object of this invention is to provide punching apparatus which is constructed to be used on die sets of the kind commonly employed in connection with presses. Another object. is to provide apparatus of this type in which the punches, when the ram is in its upper position are spaced at a considerable distance from the dies so that the insertion of the work between the punches and dies is facilitated. A further object of this invention is to provide apparatus of this type in which die plates and punch plates can be readily supported in such a manner that these plates are not subjected to strains'before or during the punching operations, to avoid such deflection of the plates as would cause the punch units to be supported out of axial alinement with the die units.

Further objects and advantages of this invention will appear from the following description and claims.

In the accompanying drawings:

Fig. 1 is the front elevation, partly in section, of a press with punching apparatus embodying my invention mounted in it and showing the ram in an elevated position.

Fig. 2 is a plan view of the lower part thereof, taken on line 22, Fig. 1.

Fig. 3 is an enlarged fragmentary view thereof, with the ram in its lowest position and the punch penetrating the work.

Fig. 4 is a fragmentary view of the same punch and punch guide as shown in Fig. 3 in its nonoperative position.

Fig. 5 is a fragmentary elevation, partly in section, of a portion of my apparatus, showing a pilot locator pin cooperating with a prepunched locating hole in the workpiece for correctly positioning the workpiece with reference to the punches and dies.

Fig. 6 is a fragmentary sectional elevation, showing a sleeve used for aligning the punch and die elements when installing the assembled punch plate and its companion die plate to their respective holders? i Fig. 7 is a fragmentary sectional elevation of a punching apparatus of modified construction, the punch units being shown in the positions which they occupy when the rain has been moved downwardly through a part of its stroke.

Fig. 8 is a fragmentary plan view of the die plate and a die unit as seen along line 88, Fig. 7.

Fig. 9 is a fragmentary top plan view of one of the punch units shown in Fig. '7.

Fig. 10 is an elevation, on a reduced scale, of still another modified form of my invention'.

My improvedpunching apparatus may be used on a press or machine of any suitable construction, that shown including a stationary bed it having frame members I! on which. ram i2 is guided to reciprocate toward and away from the bed. Upon the bed, a bolster plate i3 is mounted as standard procedure in most stamping plants and upon this bolster is mounted a lower die shoe it. Bolster plate l3 isbolted firmly to bed It and die shoe i4 is in turn bolted firmly to the bolster plate. To the ram of'the press a punch holder or shoe is is firmly attached so that it moves toward and away from the die shoe it when the ram reciprocates In order to assure proper alignment between punch and die implements which are interchangeably mounted on punch holder I 5 and die shoe i i, conventionalmeans are provided for guiding these two members, including guide posts l6 which are mounted firmly in die shoe It and companion die bushings I! are mounted in punch holder 85. Thus upon being lowered, the openings in bushings l'i cooperate with guide posts it to assure proper alignment between the punch holder and die shoe.

In stamping plant practice the die shoe it, guide posts it, punch holder i5, and bushings I7, is referred to as a die set. While a die set is preferably employed to ensure accuracy of movement of the'punches relatively to the dies, yet my invention may be used without a die set if a press is available in which the ram moves accurately toward and from the bed, or if other-means are provided for ensuring accurate axial movement of the punches relatively to the dies. Consequently, in the claims, the bolster plate l3 and the die shoe I 4 of the die set, unless specifically mentioned, are considered as a part of the bed of the press, and the punch holder i5, unless specifically mentioned, is considered as part of the ram.

It is the purpose of this invention to place the master die set in the press as shown in Fig. 1 and allow it to remain in place while the punch and die implements are changed to perform different patterns of hole punching operations on different kinds of work.

In the preferred construction as shown in Fig.

1, I fasten securely to punch holder ll, spacer supports l8 which have tapped holes IQ for the accommodation of screws 20 which are used to hold punch plate 2| firmly attached to said spacer supports. When the workpieces are large and require large punch plates 2|, additional spacer supports l8a, which may be in the form of posts, may be provided at intermediate portions of the punch holder I and punch plate 2| to prevent sagging or deflection of the punch plate.

In die shoe I4, I provide tapped holes 22 for the accommodation of screws 23 which are used to hold die plate 24 firmly in position on die shoe l4.

In preparing to punch holes in various sizes and shapes of parts, the blank punch plate 2| is clamped to die plate 24 in such manner that holes may be formed in both plates in exact relation and alignment with one another, as shown in Figs. 2, 3, and 4 of my Patent No. 2,275,- 706 of March 10, 1942, these holes being formed according to the pattern of holes required in the work. The plates are then separated and prepared in any suitable manner for use in erforating the work. For example, the holes in one or other of the two plates may be enlarged to receive punch or die units. In the construction shown in Figs. 1 to 4, the holes 25 formed in die plate 24 may have die elements pressed into them in such manner that the lower end 21 will be in contact with the upper face of the die shoe l4 when in operation. Each die element 26 is provided with a die opening 28 which is slightly larger in size than its companion punch and which communicates with a cross passage 29 through which the punch-out slugs are cleared from the die element. As many of these die elements 26 as are required are pressed into die plate 24 and the die openings 28 may, of course, vary to suit con 'itions. The numeral 30 represents the workpiece. Various workpiece locating gages may be used, but in this particular instance, I show locating pins '3| having locating pilots 32 which enter into-pre-punched holes 33 in the workpieces when placed in the apparatus. At least two of these locating pins are required when anything but circular work is being operated upon. These locating pins may also be pressed into holes in the die plate, as shown in Fig. 5. Any other suitable stop gage means for correctly positioning the work relatively to the die elements may be employed.

To punch plate 2| I add punching devices or punch units comprising a punch bit 34, punch body 35, and head 36, said punch bit and body being guided in a punch sleeve 31 which has a sliding fit in the holes in punch plate 2|. Punch guide sleeve 31 is provided with a head 38 which limits its downward travel and prevents it from dropping out of the punch plate when in its inoperative position, as shown in Fig. 4.

Interposed between the guide sleeve head or flange 38 and punch head 36, is a stripper spring 39 of any suitable kind which is of sufflcient strength to withdraw the punch bit 34 from the workpiece after having penetrated same.

When the punch and die units have been correctly assembled on the punch and die plates, these plates are then mounted on punch holder I5 and the die holder or shoe H of the die set. In order to facilitate this assembly, the punch and die units are preferably aligned by means of an aligning sleeve 40 which fits snugly about the die 26 and the punch guide sleeve 31. When two or more such sleeves are used, the punch and die plates can readily be placed in such positions relatively to each other that all of the punches will be in axial alignment with their dies, and the plates are then secured in place by means of the screws 20 and 23.

The punch and die plates for each type of work can, consequently, be prepared and have the punch and die units mounted thereon while out of the press, and the press is, consequently, idle only while one set of plates is removed from the die set and another set of plates is secured to the die set. When a job has been completed by punching the required number of workpieces, the punch and die units can be removed from their plates and used on other plates for another job.

It is an important feature of this invention that the punch units are so supported on the punch plate 2| that none of the forces required for perforating and stripping are transmitted to or through the punch plate, since any deflection of the punch plate would cause the punches to move out of axial alignment with the dies, thus either producing defective work or breaking the punches. By means of the constructionshown, the punch plate merely supports its own weight and the weight of the punch units mounted thereon. Consequently, the punches are so mounted on the punch plate that the upper faces of the heads of the punches are either spaced from or just barely touch the lower face of the punch holder l5 of the die set, so that the punch units are out of pressure contact with the punch holder. When so arranged, the stripper springs are not,under compression and exert no force on the punch plate 2| other than their own weight. 01 course, if in some situations it were desirable to place springs 39 under a strong initial compression, longer springs than are shown in the drawings would be used. As plate 2| would be drawn against the faces of spacers l8, this result would be accomplished, and it is to be understood that this arrangement would also be Within the scope of this invention.

In the operation of the apparatus described, when the ram I2 of the press descends, the parts mounted thereon move with the ram without relative motion until the guide sleeves 3i engage the upper face of the work 30. Thereupon farther downward movement of the ram causes the punch units to remain stationary while the punch plate 2| and punch holder l5 descend. As soon as the heads of the punches engage the punch holder 5, the punches again move downwardly, the punch bits penetrating the work and entering the die openings to perforate the work. This movement of the punches relatively to the stationary punch guide sleeves compresses the stripper springs as shown in Fig. 3.

When the ram begins its upward movement, the stripper springs again expand, thus stripping the punches from the work while urging the guide sleeves 31 downwardly against the work. When the punches are withdrawn from the work, the stripper springs preferably withdraw the lower ends of the punches into their guide sleeves to a slight extent, as shown in Fig. 4, and the punch units then move by gravity in to the position shown in Fig. 4.

In order to align the various punching elements with their companion die elements, I provide sleeves 40 which are used when setting the pairs of plates into the apparatus before finally tightening the plates in their mountings. For this down in the hole.

' movement of the guide sleeve.

purpose, the die unit and the punch guide sleeve r re made of the same outside diameter so that the aligning sleeve will accurately align-apunch unit with adie unit. If two or more of these aligning sleeves are employed, then all of the punchesand dies of the apparatus will be in correct alignment,

and then the punch and die plates may be tightly bolted respectively to the punch holder and die shoe. Any other suitable alignment means may be used, if desired.

In Figs. '1 to 9, I have shown how my improvetion shown, the die is of similar cross sectional shape as the guide sleeve, and consequently, -the non-circular holes in the punch plate andzdie plate may be formed while the two plates are the upper end thereof threaded and is provided ments may be used in connection'with non-cir cular holes or with a plurality of holes spaced closely together in such a manner that a single punch unit and die unit may produce more than one hole. In these figures, a punch guide sleeve II is provided which is of non-circular shape in cross section, and this guide sleeve is arranged in a hole in the punch plate which is of similar shape, so that the guide sleeve may slide up and The guide sleeve is provided with a plurality of apertures to receive the

punches

52 and 83, three such punches being shown in the drawings. The guide sleeve has a head or flange 54 adapted to rest on the top surface of the punch plate to limit the downward Each punch may have an individual head, but if the punches are closely spaced, the punches have their upper ends arranged in a common head 56. This may be done in any suitable-or desired manner, and in the construction shown by way 01' example, the head 58 is provided with threaded holes and the upper ends of the punches are also threaded so that they can be screwed in the holes. The punches terminate short of the upper end of the head 56 and set screws are arranged in the upper ends of the threaded holes in the head 56 and preferably engage the upper ends of the punches so as to lock the punches against turning in their heads. This construction also has the further advantage that as the

punches

52 and 53 become shortened by grinding the ends of the same for sharpening the punches, the punches may be screwed into their heads 56 to a lesser extent, so that the lower ends of the punches can be maintained in the same relation to the lower ends of the guide sleeve as when the punches were longer.

when the punches are arranged so closely together that it is not practical to provide a stripper vided, which extend through the yoke plate GI and the head or flange 54 of the guide sleeve to hold the stripper springs in place. If desired, the screws 62 may be tightened so as to place the stripper springs under initial compression. I

The die 63 for cooperation with the punch unit shown in Fig. '7 may be of any suitable or desired form, and in the construction illustrated, this die is also of elongated cross section, as shown in Fig. 8, and is provided with die holes or

apertures

64 and 65 for the punches. The die may be provided with

inclined passages

66 and 61 which connect respectively with the die holes 64 and'65 to permit the slugs or punchings to be discharged from the die. I

The die 63 is pressed into a correspondingly with a head II which is internally threaded so that it may be screwed on the upper end of the month. A look nut ll serves to hold the head II from turning relatively to the punch. The guide sleeve 13 of the punch may be similar in construction to the guide sleeves shown in Figs. 1 to 4. It will be understood that thispunch. unit is interchangeable with the punch units described in connection with Figs. 1 to 4. The multiple punch. unitshown in Fig. "I may, of course, be used in combination with otherpunch units.

It is also possible to punch non-circular holes in connection with my improved punching apparatus, and when this is done, the punch and die units must be held against turning relatively to their punch and die plates. punching non-circular holes, punch sleeves of non-circular shape, such for example as the punch sleeve 50.- and die units of non-circular shape, such as the die unit 83, may be employed, which will be held against turning relatively to their punch and die plates.

In Fig. 10, I have shown a punching apparatus of slightly modified construction, in which the punch plate and the punch units supported thereon may be similar to those described in connection with Figs. 1 to 4, but in which the die plate may be of the type disclosed in my copending application Serial No. 479,749, filed March 19, 1943. In this construction, the die plate to is provided with apertures 8| therein which serve as the dies. This die plate is supported on the die shoe It of the die set in spaced relation thereto so that the slugs or punchin g's may drop into the space below the die plate 80. Consequently, the end portions of the die plate may be supported by means of pillars or standards 83 which may be secured tothe die shoe M in any suitable manner, for example, by means of angle-shaped clamping members 86 engaged by bolts 85 to hold the pillars 83 on the die shoe Hi. If the die plate 80 is of large size, one or more intermediate supports 86 nlilay be provided between the die plate and the die s oe.

' The perforating apparatus described has the advantage that it can be used in connection with die sets in which the upper and lower shoes of the die set are guided for accurate movement relatively to each other, so that the apparatus herein disclosed is particularly suitable for cases where" a relatively large opening is desired between the punch-and die units to facilitate the correct positioning'oi' the work in the apparatus. By the use of a die set, the upper or punch holder member of which is secured directly to the ram of the press, the punch and die units may be' R shaped hole in the die plate 88. In the construc- Consequently, for

I guide sleeve, and said sacrifice of accuracy in punching. Since the die,

plate 24, as shown in Figs. 1 to 9., is supported throughout its lower surface on the die shoe of the press, no deflection of the die plate will result. The die plate 80 in Fig. can also be held in flat position by use of the required number of pedestals or supports 83 and $8. The punch plate also may be of large'size, since it may be supported not only at the edge portions thereof, but also intermediate of the edges by means of. supports its so that saggin f this plate is reduced to a minimum. It is also of importance that the punch units are so mounted on the punch plate that none of the forces required for punching the work and stripping the punches from the work pass through the punch plate. This is accomplished by providing punch units which do not extend above the punch plate to a greater extent than the space between the punch plate 2| or BI and the punch holder it. Hence the punch plate will at all times be free from any stresses, except those which result from its own weight and the weight of the guide sleeves. Consequently, by preventing sagging or deflection of the punch and die plates, the several punches will remain vat all times in correct axial alinement with their dies. 1 I

I claim as my invention: l. Perforating apparatus for use in a press having a bed and a ram movable toward and from the bed, including a punch plate secured in spaced relation to said ram and having holes therein arranged in accordance with the pattern of holes required in the work, punch units each including a punch slidably arranged in a punch guide sleeve and having a part arranged to engage said ram for forcing the punch through the work, and a stripper spring normally holding the punch within the guide sleeve and arranged in the' space between said ram and said punch plate, said sleeves being slidably fitted in said holes, and a die for each punch and mounted on said bed, said sleeves engaging the work upon descent of the ram and being slid upwardly to compress said stripper springs while the punches are forced through the work by said ram.

2. Perforating apparatus for use in a press having a bed and a ram movable toward and from the bed, including a punch plate secured in spaced relation to said ram and having holes therein arranged in accordance with the pattern of holes required in the work, punch units each including a punch, a punch guide sleeve and a stripper spring, said punch being slidable in said guide sleeve being slidable in a hole in a punch plate, said punch having a head extending into proximity to said ram and said guide sleeve having a flange on its upper portion, said stripper spring being arranged between said head and flange, a die for each punch and from the bed, including a punch each including a punch guide sleeve slidably mounted in a hole in said plate and having a flange at its upper-"end to limit downward movement of said punch guide sleeve relatively to said punch plate, a punch slidable in said guide sleeve and having a head on the upper end thereof spaced above said flange, and a stripper spring arranged between said head and said flange, means for securing said punch plate to said punch holder of the die set in such spaced relation thereto that such springs will be substantially free from compression, a die plate secured to said die holder of said die set with die holes arranged in axial alignment with said punches, said sleeves upon downward movement of said punch plate and the punch holder of said die set being slid upwardly in their holes upon engagement with the work to compress said stripper springs while said punches are forced through the work, the pressure of said springs upon upward movement of said punch plate and punch holder stripping the work from said punches.

4. Perforating apparatus for use in a press having a bed and a ram movable toward and plate secured in spaced relation to said ram and having holes therein arranged in accordance with the pattern of holes required in the work, punch units each including a punch slidably arranged in a punch guide sleeve and having a part arranged to engage said ram for forcing the punch through the work, and a stripper spring normally holding the punch within the guide sleeve and arranged in the space between said ram and said punch plate, said sleeves being slidably fitted in said holes, a die plate having holes therein and secured to said bed and having a plurality of die units pressed into said holes and extending upwardly above mounted on said bed, saidsleeves, upon descent of said ram, engaging the work and being moved by the work upwardly to compress said springs while said punches are moved by said ram through the work.

3. Perforating apparatus for use in a press having a bed and a ram movable toward and from the bed, and having a die set mounted in said press with a die shoe secured to said bed and a punch holder secured to said ram, a punch plate having holes formed therein according to the pattern of holes required in the work, punch units arranged in said holes in said punch plate and said plate and having die openings in axial alignment with the punches, said sleeves upon descent of said ram engaging the work resting on said dies and being slid upwardly by contact with the work to compress said stripper springs while the punches are forced through the work by said ram.

5. Perforating aparat'us for use in a press having a bed and a ram movable toward'and from the bed, including a punch plate secured in spaced relation to said ram and having holes therein arranged in accordance with the pattern of holes required in the work, punch units each including a punch slidably arranged in a punch guide sleeve and having a part arranged to engage said ram for forcing the punch through the work, and a stripper spring normally holding the punch within the guide sleeve and arranged in the space between said ram and said punch plate, said sleeves being slida-bly fitted in said holes, and a die plate 'mounted in spaced relation to said bed and having die holes therein each of which is in axial alignment with a punch on said punch plate, said sleeves upon descent of the ram engaging the work and being slid upwardly to compress said stripper springs while the punches are forced through the work by the ram.

6. A punch plate for use on the ram of a press, said punch plate having a plurality of apertures formed therein in accordance with the pattern of holes required in the work, a punch guide sleeve slidably mounted in each aperture and having a flange at the upper end to limit the downward movement of the guide sleeve in its hole, a'punch slidably arranged in said guide sleeve and extending above the same, a head on said punch, and a stripper spring arranged to act on said head and said flange for holding the work penetrating end of the punch within said sleeve.

7. The combination of a punch plate for use on the ram of a press, said punch plate having a plurality of apertures formed therein in accordance with the pattern of holes required in the work, a punch guide sleeve slidably mounted in each aperture and having a flange at the upper end to limit the downward movement of the guide sleeve in its hole, a punch slidably arranged in said guide sleeve and extending above the same, a head on said punch, a stripper spring arranged to act on said head and said flange for holding the work penetrating end of the punch within said sleeve, and means for mounting said punch plate in spaced relation to the ram 01 the press with the heads of the punches clearing the ram the press to prevent compression ofsaid spri s and deflection of said punch plate.

8. The combination of a die plate for use on the bed of a press, said die plate having a plurality of apertures formed therein in accordance with the pattern of holes required in the work, die units having their lower portions formed to be pressed into said holes with their lower ends flush with the bottom of said die plate, said die units having apertures in the upper ends thereof and discharge openings connecting with said die apertures and terminating in the sides of said units above said plate for discharging punchings on said plate, and means for securing said die plate on the bed of a press.

9. A perforating apparatus, including a die set having a die shoe and a punch holder guided for accurate movement toward and from the die. shoe, a punch plate having apertures therein located according to the pattern of holes desired in the work, means for securing said punch plate in spaced r lation to said punch holder, and a plurality of punch units each including a guide sleeve slidable in an aperture in the punch plate, a punch slidable in said sleeve and extending above said sleeve, and a stripper spring acting on the up er portion of the punch and the guide sleeve, said punch units extending above said punch plate a distance not greater than the space between said punch plate and said punch holder to prevent said units from exerting pressure on said punch plate when the,same is secured to said Punch holder.

10. The combination with a die set having a die shoe and a punch holder guided for accurate movement toward and from the die shoe, of a punch plate having a plurality of punch and stripper units including punches, punch guide sleevesand stripper springs i-loatingly mounted on said punch plate, and means for supporting said plate in spaced relation to the punch holder of the die set with the punch and stripper units out of pressure contact with said punch holder, to p rmit the punches of said units to move into engagement with the punch holder when engaging the work.

11.'The combination with a die set having a die shoe and a punch holder guided for accurate movement toward and from the di shoe, of a punch plate having a plurality of punch and stripper units including a punch guide sleeve slidable vertically relatively to said plate, punches slidable in said sleeves, and stripper springs yieldingly holding the Work penetrating ends of said punches in said sleeves, and means for supporting said plate in spaced relation to the punch holder oi the die set with the punch and stripper units out of pressure contact with said punch holder, to permit the punches or said units to move into engagement with the punch holder whenengaging the work.

12. Perforating apparatus for use in a press said sleeves slide in said holes.

, 13. A perforating apparatus for use on a press including a, punch plate and a die plate, said plates having aligned non-circular holes therein, a guide sleeve of non-circular cross section slidably arranged in the hole in said punch plate and held against turning relatively to said punch plate, a punch slidable in said sleeve and having the upper end thereof extending above said sleeve, a stripper spring acting on said sleeve and said punch for urging the work engaging end of said punch into said sleeve, and a die oi noncircular cross section arranged in said hole in said die plate and having a punch receiving opening thereinarranged to receive said punch when said plates are arranged in operative relation to each other.

14. A perforating apparatus for use on a press including a punch plate and a die plate, said plates having aligned non-circular holes therein, a guide sleeve of non-circularcross sectionslidably arranged in the hole in said punch plat and held against turning relatively to said punch plate, a plurality of punches slidably arranged in said sleeve, stripper springs acting on said punches and sleeves and urging the work penetrating ends of said punches into said sleeves, and a die of non-circular cross section arranged in said hole in said die plate and having a plurality of apertures therein to receive said ends of said punches.

15. A perforating apparatus for use on a press including a punch plate and a die plate, said plates having aligned non-circular holes therein, a guide sleeve .of non-circular cross section slidably arranged in the hole in said punch plate and held against turning relatively to said punch plate and having a plurality of holes extending lengthwise through the same, punches slidably arranged in said holes, a head to which the upper ends of said punches are secured, resilient stripping means for the punches, which act on said head, and said sleeve to draw the work penetrating ends of the punches into said sleeve, and a die of non-circular cross section arranged in said hole in said die plate and having a plurality of apertures therein to receive said work penetrating ends of said punches.

16. A perforating apparatus for use on a press including a punch plate and a die plate, said plates having aligned non-circular holes therein, a guide sleeve of non-circular cross section slidably arranged in the hole in said punch plate and held against turning relatively to said punch plate and having a plurality of holes extending lengthwise through the same, punches slidably arranged in said holes, a head to which the upper ends of said punches are secured, a yok engaging said head, and stripper sp ings engaging said yoke and said sleeve to draw the work penetrating ends of said punches into said sleeve, and die means with which said punches cooperate to per-. forate the work.

1'7. A punch plate for use on the ram 01 a press, said punch plate mounted in spaced relation to said ram and having a hole therein, a

guide sleeve slidably arranged in said hole. a

punch slidably arranged in said sleeve and having a part extending above said sleeve for engagement with said ram and having a screw-threaded upper end, a head having a threaded hole and engaging said screw-threaded end of said punch, and a screw plug in the upper end 01 said screwthreaded hole and engaging said punch for locking said punch against turning relatively to its head.

18. A punch platefor use on the ram of a press, said punch plate mounted in spaced relation to said ram and having a hole therein, a

guide sleeve slidably arranged in said hole, a punch slidably arranged in said sleeve and having a part extending above said sleeve for engagement with said ram and having a screwthreaded upper end, a head having a threaded hole and engaging said screw-threaded end of said punch, and a lock nut on said punch and engaging said head to hold said punch against turning relatively to said head.

19. The combination with a die set having a die shoe and a punch holder guided for accurate movement toward and from the die shoe, of a punch plate having a plurality of punch and stripper units including punches, punch guide sleeves and stripper springs floatingly mounted on said punch plate, means for supporting said plate in spaced relation to the punch'holder of the die set with the punch and stripper units out'of pressure contacts with said punch holder, to permit the punches of said units to move into engage- ,ment with the punch holder when engagin the work, and a die plate having die apertures for cooperation with said punches and mounted in spaced relation to said die shoe.

20. The combination with a die set having a die shoe and a punch holder guided for accurate movement toward and from the die shoe, or a punch plate having a plurality of punch and stripper units includingpunches, punch guide sleeves and stripper springs floatingly mounted on said punch plate, means for supporting said plate in spaced relation to the punch holder of the die set with the punch and stripper units out of pressure contact with said punch holder, to permit the punches of said units .to move into engagement with the punch holder when engaging the work, a die plate having die apertures for cooperation with said punches, and a plurality of supporting members secured to said die shoe and said die plate for mounting said die plate in spaced relation to said die shoe.

21. The combination with a die set having a die shoe and a punch holder guided for accurate movement toward and from said die shoe, of a punch plate having a plurality of punch units mounted thereon including guide sleeves extending below the lower face thereof, a die plate having a plurality of die units mounted thereon and extending above said die plate, and a plurality of aligning sleeves with which some of the guide sleeves and their corresponding die units may telescope to hold said plate in positions in which each of said punch units is in axial alignment .punch plate having a plurality of punch units mounted thereon including guide sleeves extending below the lower face thereof, a die plate having a plurality of die units mounted thereon and having cylindrical outer surfaces of the same diameter as said sleeves and extending above said die plate, and a plurality of cylindrical aligning sleeves into which said guide sleeves and die units may telescope to hold said plates in positions in which each of said punch units is in axial alignment with its die unit, while said plates are secured to said die set.

23. The combination of a die plate for use on the bed-of a press, said die plate having a plurality of dies arranged thereon in accordance with the pattern of holes required in the work, pilot means on said die plate, including pins formed to enter into preformed holes in the work, for locating the Work in correct relation to the dies of said die plate, and a punch plate having punches mounted thereon arranged for cooperation with said dies said pilot means being positioned within the area under said punch plate.

24. The combination of a die plate for use on the bed of a press, said die plate having a plurality of dies arranged thereon in accordance with the pattern of holes required in the work, die units having their lower portions formed to be pressed into said holes of said die plate, and locating units having shank portions formed to be pressed into some of said holes and having locating pins at their upper ends formed to enter into preformed holes in the work, and means for securing said die plate on the bed of the press said locating units being positioned within the area under a punch plate which carries die cooperating punches.

25. The combination of a die plate for use on the bed'of a press, said plate having a plurality of apertures formed therein in accordance with the pattern of holes required in the work, die units of substantially uniform cross section throughout their length having their lower portions formed to 'be pressed. into said holes of said die plate with their lower ends flush with the bottom of said die plate, said die units having die apertures formed axially in the upper ends of said die units and having slug discharge apertures in which said die apertures terminate, said discharge apertures terminating in the sides of said units above said plate, and means for securing said die plate to the bed of the press.

26. The combination of a die plate for use on the bed of a press, said die plate having a plurality of apertures formed therein in accordance with the pattern of holes required in the work, die units having their lower portions formed to be pressed into said holes with their lower ends flush with the bottom end of said die plate and their upper portions being provided with a lateral slugclearing aperture for emitting slugs above said die plate, and means for securing said die plate on the bed of the press.

GEORGE F. WALES.