Cutting – With product handling means – Means to move – guide – or permit free fall or flight of product
Reexamination Certificate
1998-12-28
2001-11-06
Rachuba, M. (Department: 3724)
Cutting
With product handling means
Means to move, guide, or permit free fall or flight of product
C083S139000, C083S684000, C083S686000, C083S698910
Reexamination Certificate
active
06311594
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a punch guiding apparatus which composes a portion of a punch metal mold to be used for punch press and relates to a stripper plate to be used therefor, further relates to a method of punching a punch guide hole in a blank holder of a punch assembly which is used in a state of being attached to a punch holder in a punch press such as a turret punch press, a punch assembly and a blank holder.
2. Description of the Related Art
A punch assembly in the related art has disclosed the construction that it comprises a punch body having a punching portion at its lower end portion being vertically movably housed in a punch guide which is vertically movably supported onto a turret-like punch holder of a turret punch press, and a plastic blank holder being removably fitted into a fitting groove formed in a lower end portion of the punch guide.
In the aforesaid related art, a cylindrical projecting portion of the blank holder is fitted into the fitting groove of the punch guide, and thereafter, the punch body is inserted into the punch guide. And then, the punching portion of the punch body is subjected to punching so as to punch a punch guide hole in the blank holder.
More specifically, according to the related art, in the case where the blank holder is attached to the punch guide, there is a need of previously removing the punch body from the punch guide so that the punching portion does not become obstructive. For this reason, there has arisen a problem that an attachment of the blank holder is considerably troublesome.
Moreover, in the case where the plastic blank holder is replaced with a new blank holder due to a deterioration or damage caused therein, there has arisen a problem that it is very difficult to remove the blank holder from the punch guide because the blank holder is fixedly fitted so as not to come off therefrom due to vibration, etc.
In the related art construction, in the case where the blank holder is made of a rigid plastic, there is a problem that a great pressing force is required when the blank holder is fitted into the groove of the punch guide. As the case may be, there has arisen a problem that an annular stopper convex portion which projects from an outer peripheral face of the projecting portion is chipped off therefrom.
Furthermore, in the case where the blank holder is made of a relatively soft material, there is a problem that the blank holder does not act and not exhibit its function and is lack of durability.
SUMMARY OF THE INVENTION
The present invention has been achieved with such points in mind.
It therefore is an object of the present invention to provide a punch guiding apparatus and a stripper plate to be used therefor which improve the durability when the stripper plate is mounted to and detached from a punch guide and strengthen a mounting force of the stripper plate.
It is another object of the present invention to provide a punch assembly in which removal of the blank holder can be readily achieved.
It is still another object of the present invention to provide a blank holder which can be readily fitted into the groove formed in the punch guide.
It is further object of the present invention to provide a method of punching a punch guide hole in a blank holder in which attachment of the blank holder to the punch guide and punching of the punch guide hole of the blank holder can be readily achieved.
To achieve the object, according to a first aspect of the present invention, there is provided a method of punching a punch guide hole in a blank holder while attaching the blank holder to a lower end portion of a punch guide in a punch assembly constructed in a manner that a punch body having a punching portion at its lower end portion is vertically movably housed in the punch guide vertically movably supported onto a punch holder, comprising the steps of: fitting lightly a distal end portion of a cylindrical projecting portion of the blank holder into a fitting groove formed in the lower end portion of the punch guide so that the distal end portion is momentarily held in the blank holder; and fitting forcedly the projecting portion of the blank holder into the fitting groove formed in the punch guide and punching the punch guide hole in the blank holder by pressing a punch head of a punch body of the punch assembly so that the punch guide descends and presses the blank holder against a die provided opposite to the blank holder.
Thus, the blank holder is fitted into the fitting groove by taking use of a downward pressing force of a striker, etc., so that attachment of the blank holder to the punch guide and punching of the punch guide hole of the blank holder can be readily achieved.
According to a second aspect of the present invention, there is provided a punch assembly, comprising: a punch guide vertically movably supported onto a punch holder; a punch body having a punching portion at its lower end portion vertically movably housed in the punch guide; and a blank holder is removably fitted into a fitting groove formed in a lower end portion of the punch guide, wherein the punch guide or the blank holder being formed with an inclined plane constructed so that a distance between the punch guide and the blank holder is widened toward the outside thereof, at part of an outer peripheral face on a lower end portion of the punch guide or part of an upper face of a flange of the blank holder.
With the above construction, by forcing pawls of a removal tool to bite into the inclined plane so as to abut against the inclined plane, a component in a direction of removing the blank holder from the punch guide acts thereon, so that the removal of the blank holder can be readily achieved.
According to a third aspect of the present invention, as it depends from the second aspect, wherein the inclined plane is formed on the outer peripheral face on a lower end portion of the punch guide or on the upper face of the flange of the blank holder so as to gradually guide the pawls of the removal tool between the lower end portion of the punch guide and the flange of the blank holder.
Thus, a component in a direction of removing the blank holder from the punch guide acts thereon, so that the removal of the blank holder can be readily achieved, as described above.
According to a fourth aspect of the present invention, as it depends from the second or third aspect, the punch assembly further comprises an elastic member is interposed between the punch guide and the blank holder, wherein the blank holder is retained onto the punch guide by means of the elastic member.
Thus, attachment of the blank holder to the punch guide can be readily achieved regardless of material quality of the blank holder. Also, there is no problem such that protrusions of the blank holder is not chipped off when attaching the blank holder to the punch guide.
According to a fifth aspect of the present invention, as it depends from the second, third or fourth aspect, wherein the blank holder is made of a rigid resin or metal, and the lower end face of the punch guide and the flange of the blank holder face each other.
Thus, the blank holder sufficiently acts or exhibits its function in operating.
According to a sixth aspect of the present invention, as it depends from the second, third, fourth or fifth aspect, wherein the flange of the blank holder has a thickness thicker than a bottom portion on an inside of the projecting portion formed on the blank holder.
Thus, the projecting portion of the blank holder is securely fitted into a fitting groove formed in the punch guide while punching of a punch guide hole being carried out. Therefore, the punch guide hole can be accurately punched in the blank holder.
According to a seventh aspect of the present invention, there is provided a blank holder attached to a lower end portion of a punch guide of a punch assembly, comprising: a blank holder being formed with a fitting projecting portion being capable of fitting into a fitting groove formed in the lower end portion of t
Amada Company Limited
Blank Rome Comisky & McCauley LLP
Rachuba M.
LandOfFree
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