Die set with two-part leader pins and ball bearing guide

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure.
The scope of the invention is defined in the claims appended hereto.
The die set conventionally includes a punch holder 10 connected to a mounting lug 12, and a die shoe 14.
The punch holder 10 carries a punch or male die member 16, and a female die 18 is supported on the die shoe 14.
In accordance with the invention there are provided upper leader pin portions 20 which can have tapered shanks 22 in a press fit in apertures 24 in the punch holder 10.
The leader pin portions 20 are also provided with a tapered surface 26 which can be a continuation of tapered surface 22.
The lower leader pin portions 32 can have tapered surfaces 34 received in tapered apertures 36 in the die shoe 14.
Projecting above the die shoe is a lower leader pin shank portion 38.
The shank portions 38 are connected to sleeves 40.
Means are provided for adjustably securing the sleeve 40 to the lower leader pin portion 32.
In the construction disclosed in FIG.
1, the means comprises set screws 44.
The set screws 44 enable adjustment of the position of the sleeve 40 relative to the die 18 or material to be punched 39 to prevent penetration of the punch into the female die.
The sleeves 40 are provided with a bore 52 having an internal surface 54.
Located within the bore 52 is a ball bearing cage 56 containing a plurality of bearing balls 58.
The bearing balls 58 are supported in the cage 56 and provide a throat 60 which receives the upper leader pin portion 20.
The bearing balls 58 can be arranged in generally vertical rows 62 to provide uniform contact along the sleeve 50.
FIG.
2 shows a bearing cage 64 with 3 vertical rows of balls with the rows equally spaced at an angle C of 120.
degree.
about the vertical axis 66 of the cage.
Such a row orientation is believed to give maximum precision to the guided movement of the punch 16