U.S. patent number 3,707,303 [Application Number 05/122,947] was granted by the patent office on 1972-12-26 for means for securing an insert to a base piece.
This patent grant is currently assigned to Petri-Johnson, Inc.. Invention is credited to Nello J. Petri.
United States Patent |
3,707,303 |
Petri |
December 26, 1972 |
MEANS FOR SECURING AN INSERT TO A BASE PIECE
Abstract
Means for removably securing an insert element to a larger base
piece. The invention as disclosed solves the problem of securing an
insert element such as a punch to a larger base piece such as a
punch ring. The invention is particularly applicable to a rotary
punch of the type having a rotating punch ring with punch elements
removably secured around the periphery of said ring. In lieu of the
usual set screw method of securing the punches to the punch ring
quick releasable means is provided for fixedly but removably
securing the shank of a punch or the like within a bore in the
punch ring. The cross sectional contour of the shank or the bore is
formed so that the shank engages the bore at two points in cross
section. The shank is forced against said two points by means of a
spring pressed ball so that the insert is urged simultaneously
against the bottom of the bore and against the two points. The
"three point support" thus achieved insures not only optimum
stability of the insert with respect to the punch ring but also
permits extremely accurate positioning of the punch relative to the
punch ring.
Inventors: |
Petri; Nello J. (San Francisco,
CA) |
Assignee: |
Petri-Johnson, Inc. (San Jose,
CA)
|
Family
ID: |
22405829 |
Appl.
No.: |
05/122,947 |
Filed: |
March 10, 1971 |
Current U.S.
Class: |
403/328; 279/30;
403/361 |
Current CPC
Class: |
F16B
21/165 (20130101); F16B 2200/10 (20180801); Y10T
279/17196 (20150115); Y10T 403/604 (20150115) |
Current International
Class: |
F16B
21/16 (20060101); F16B 21/00 (20060101); F16b
001/00 () |
Field of
Search: |
;83/698 ;279/30,83,76
;287/52.08,20.3 ;299/92 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kundrat; Andrew V.
Claims
I claim:
1. In the combination that includes a base piece and an element
secured thereto:
said base piece being formed with a bore opening outwardly of one
face thereof,
said element including a shank adapted to be received in said bore
through the open end thereof,
spring urged force means on one side of said bore urging said shank
transversely of said bore toward the opposite side thereof,
said shank and bore being formed in cross section to provide two
spaced points of engagement between said shank and said bore at
said opposite side,
the cross sectional contour of said shank being smaller than the
cross sectional contour of said bore to provide clearance
therebetween whereby the periphery of said shank is engaged only by
said force means and said bore at said two points to provide
stability of said element relative to said base piece,
said bore being provided with a bottom rigid with said base piece
and said shank being provided with a camming surface acted upon by
said spring urged force means to urge said shank against said
bottom at the same time it is urged toward said opposite side,
said bore and shank being circular in cross section and said bore
being enlarged at the side opposite said force means to provide a
pair of junctures at said points extending axially of said
bore.
2. In the combination that includes a base piece and an element
secured thereto:
said base piece being formed with a bore opening outwardly of one
face thereof,
said element including a shank adapted to be received in said bore
through the open end thereof,
spring urged force means on one side of said bore urging said shank
transversely of said bore toward the opposite side thereof,
said shank and bore being formed in cross section to provide two
spaced points of engagement between said shank and said bore at
said opposite side,
the cross sectional contour of said shank being smaller than the
cross sectional contour of said bore to provide clearance
therebetween whereby the periphery of said shank is engaged only by
said force means and said bore at said two points to provide
stability of said element relative to said base piece,
said bore being provided with a bottom rigid with said base piece
and said shank being provided with a camming surface acted upon by
said spring urged force means to urge said shank against said
bottom at the same time it is urged toward said opposite side,
the radius of said bore being less than the distance from the
center of the bore to another face of said base piece whereby the
bore intersects said other face to provide said points of
engagement.
3. In the combination that includes a base piece and an element
secured thereto:
said base piece being formed with a bore opening outwardly of one
face thereof,
said element including shank adapted to be received in said bore
through the open end thereof,
spring urged force means having a substantially spherical camming
surface on one side of said bore urging said shank transversely of
said bore toward the opposite side thereof,
said shank and bore being formed in cross section to provide two
spaced points of engagement between said shank and said bore at
said opposite side,
the cross sectional contour of said shank being smaller than the
cross sectional contour of said bore to provide clearance
therebetween whereby the periphery of said shank is engaged only by
said force means and said bore at said two points to provide
stability of said element relative to said base piece,
said bore being provided with a bottom rigid with said base piece
and said shank being provided with an angled camming surface acted
upon by said spring urged force means to urge said shank against
said bottom at the same time it is urged against said opposite
side,
said camming surface being formed at such an angle so as to provide
a component of the force of said force means urging said shank
against said opposite side which is greater than the component
urging said shank against said bottom.
Description
This invention relates to means for accurately and firmly
positioning a replaceable element with respect to a larger member
or base piece. The invention will be described with respect to
replaceable punch elements which are inserted in the periphery of a
rotatable punch ring for the purpose of punching holes in a paper
strip or the like. However it will be apparent that the invention
herein disclosed is applicable to many other situations wherein it
is desired to fixedly secure an element with respect to a base
piece so that such element may be removed and a similar element
replaced with a minimum loss of time.
Heretofore paper punches of the type which include a ring rotatably
supported relative to a moving web of paper have been provided with
replaceable punches which are fixedly secured in radially outwardly
opening bores in the ring periphery. In order to fixedly secure
said punches relative to the ring the procedure in the past has
been to employ a set screw threadedly secured within the ring and
which screw may be tightened against the shank of the punch. Since
such punches must be replaced quite frequently it has been a time
consuming operation to release each one of the screws securing the
punch elements and then tighten such screws after the new punch
elements have been replaced. The reason for employing such screw
means for holding the punch elements is that a high degree of
accuracy is desired in punching apparatus and the set screws
provide means for not only holding the punch element in a fixed
position with reference to the punch ring bore but, since the punch
element is urged against one side of the bore a high degree of
accuracy is ensured.
The main object of the present invention is the provision of means
for fixedly securing punch elements within the periphery of a
rotatable punch ring without the use of set screws and similar
devices requiring manual loosening and tightening.
Another object of the invention is the provision of a relatively
simple holding device which not only secures the removable element
in place relative to the base piece but also insures a high degree
of accuracy in locating the element relative to the bore within
which it is received thus adding to the life of the punch.
Other objects and advantages will be apparent from the following
specification and from the drawings:
FIG. 1 is a fragmentary side view of a punch ring showing a
plurality of punch elements in the periphery thereof.
FIG. 2 is a greatly enlarged cross sectional view of the punch ring
showing the insert in place and the holding means therefor.
FIG. 3 is a transverse cross sectional view through the bore
showing the shank or the punch element received therein. The
clearance between the shank of the punch element and the bore in
which it is received is greatly exaggerated for clarity.
FIG. 4 is a view similar to FIG. 3 showing a modified form of the
invention.
FIG. 5 is a view similar to FIG. 3 showing another modified form of
the invention.
In detail, and first with reference to FIG. 1, the invention will
be disclosed with reference to a punching apparatus for punching
holes in a web of paper or the like. Such an apparatus includes a
punch ring generally designated 1 carried by a shaft 2 which is
rotatably supported in suitable bearings (not shown). Upon rotation
of the ring 1 over a moving web of paper the punches 3 on the
periphery thereof cooperate with dies on a die ring (not shown) to
punch holes in the paper at predetermined spaced points along the
length of the latter. After a period of use the punches 3 become
worn and must be replaced. Although such replaceable punches are
relatively inexpensive the operation of removing the old punches
and replacing them with new ones is a time consuming one since it
is required to release and tighten set screws for holding such
elements in place. The present invention is not concerned with the
punching operation itself but is concerned merely with the step of
removing the old punch elements and replacing them with new
ones.
As best seen in FIG. 2 the periphery of ring 1 is provided with a
plurality of radially extending outwardly opening bores 5 each of
which is provided with a bottom 6. The punch generally designated 3
is provided with an elongated shank portion 7 which may be a few
thousandths of an inch less in diameter than the diameter of bore
5. On one side of the bore 5 a transversely extending opening 9 is
drilled to receive a ball 10 and a strong compression spring 11.
All of the springs may be secured in place by a single annular
spring retainer 12 fixed to ring 1 by bolts (not shown). The spring
11 urges the ball 10 toward the adjacent side of the shank 7 and
the inner end of hole 9 may be made frustoconical or spherical as
indicated at 14 to retain the ball within the hole 9 when the shank
7 is removed.
The ball 10 cooperates with a V-shaped groove 15 extending around
the periphery of shank 7 and having a pair of straight intersecting
sides 16, 17. As seen in FIG. 2 the length of shank 7 and the
location of hole 9 is predetermined so that the ball 10 engages the
camming surface 17 thus urging the inner end of shank 7 against the
bottom 6 of the bore. The force of the spring 11 also urges the
shank 7 against the side of the bore 5 that is opposite the ball
10. As best seen in FIG. 3 said opposite side of the bore 5 is
enlarged, preferably by milling, as indicated at 19. The depth of
such enlargement 19 need not be very great but merely sufficient to
cause the shank 7 to engage the inner side of the bore 5 along
lines A and B (FIG. 3) extending longitudinally of the bore. By
this structure it will be apparent that the shank 7 is subjected to
a "three point support" in the sense that the ball 10 and the lines
of engagement A, B are the only external means in engagement with
the punch shank 7 (neglecting the effect of the bottom 6 of the
bore on the inner end of the shank). It will be understood that the
clearances between the shank 7 and the bore 5 and the enlargement
19 are exaggerated in FIG. 3 for clarity. Actually in practice only
a few thousandths of an inch clearance is required between the
shanks 7 and the bore 5 in order to simplify the insertion and
removal of the shank 7 relative to the bore 5.
It has been found that the desired stability of the shank 7
relative to the drum 1 cannot be achieved merely by urging the
shank against the opposite cylindrical side of the bore 5. In other
words if the lines of engagement indicated at A and B are not
clearly defined as by providing the enlargement 19 the shank 7
tends to rock within the bore 5 thus making it impossible to keep
the punch located with the desired degree of accuracy.
The inner end of the shank 7 may be tapered as indicated at 21 to
facilitate the insertion of the shank within the bore.
The "three point support" noted above is of course actually brought
about by the engagement of the shank 7 along two lines and the
point at which the ball 10 engages the camming surface 17. Thus the
term "three point support" as used herein is not exactly accurate
but describes the important principle that by engaging the shank 7
at three different locations optimum stability is achieved. The
efficacy of the structure is further enhanced by the presence of
groove 15 which divides each of the lines of engagements A, B into
two spaced parts so that there are, in effect, four lines of
engagement on one side and point engagement on the opposite
side.
Another form of the invention which also provides the so called
"three point support" is shown in FIG. 4 wherein the ring 1' is
provided with a side 30 spaced from the center line of the bore 5'
a distance less than the radius of the latter so that the bore
breaks out through said side 30. By this structure the shank 7
engages the inner side of the bore at points A' and B' thus
achieving a comparable stable support for the shank 7.
An analogous structure is shown in FIG. 5 wherein the ring 1" is
provided with a bore 5 of circular cross section and the shank 7'
is formed to provide a flat 32 along the side opposite the side
engaged by the ball 10. By this structure it will be apparent that
similar supporting lines A", B" are provided so as to effect a
situation analogous to that shown in FIG. 3.
The stability of the punch 3 relative to the ring 1 is further
enhanced by the fact that the ball 10 urges the shank 7 against the
bottom of the bore. Since the punching forces acting on the shank 7
tend to tilt it in a plane normal to the plane of the paper (FIG.
2) the cooperation of the inner end of the shank 7 with the bottom
6 also assists in resisting such tilting.
The very specific description of the invention herein disclosed
should not be taken as restrictive as it will be apparent that
various modifications in design may be resorted to by those skilled
in the art without departing from the scope of the following
claims.
* * * * *